2025, 39(5): 633-638.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0570
Abstract:
The investigation of deeply-buried long tunnels is currently a world-class challenge encountered in engineering construction. This article introduces the development history and current status of China’s major water transfer projects, and analyzes the significant engineering geological problems faced during the construction of deep-buried long tunnels, such as large deformations in soft rocks, water inrushes with muddy debris, high external water pressure, rock bursts, and toxic and harmful gases etc. In response to the theoretical, technical, and environmental constraints currently faced in the exploration of deep-buried long tunnels, the article proposes countermeasures such as conducting thorough preliminary exploration work, avoiding geological risks as much as possible through scheme comparison and selection, selecting appropriate construction methods, establishing geological risk mitigation plans in advance, conducting advanced geological predictions during the construction period, and promptly addressing any issues discovered.
The investigation of deeply-buried long tunnels is currently a world-class challenge encountered in engineering construction. This article introduces the development history and current status of China’s major water transfer projects, and analyzes the significant engineering geological problems faced during the construction of deep-buried long tunnels, such as large deformations in soft rocks, water inrushes with muddy debris, high external water pressure, rock bursts, and toxic and harmful gases etc. In response to the theoretical, technical, and environmental constraints currently faced in the exploration of deep-buried long tunnels, the article proposes countermeasures such as conducting thorough preliminary exploration work, avoiding geological risks as much as possible through scheme comparison and selection, selecting appropriate construction methods, establishing geological risk mitigation plans in advance, conducting advanced geological predictions during the construction period, and promptly addressing any issues discovered.
2025, 39(5): 639-647.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0287
Abstract:
Pipe jacking has a significant impact on the stability of river embankments due to its small working surface and high stacking load. The early prediction of river embankment deformation is of great significance for safe construction. The Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) method was employed to decompose the nonlinear and unstable monitoring data into trend and periodic terms, and an intelligent prediction model (CTG) suitable for river embankment deformation was proposed. The model used a polynomial function to predict the trend item, and a time convolution network-gated recurrent unit hybrid model combined with a particle swarm optimization algorithm (i.e., PSO-TCN-GRU algorithm) was used to predict the periodic term. It was found that the intelligent algorithm proposed is superior to other classical neural network prediction methods, and has a certain promotional value, which can provide reference for the deformation prediction of similar projects. In addition, it is suggested that data decomposition and feature extraction should be carried out before monitoring data prediction, which is conducive to improving the prediction results of the model.
Pipe jacking has a significant impact on the stability of river embankments due to its small working surface and high stacking load. The early prediction of river embankment deformation is of great significance for safe construction. The Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) method was employed to decompose the nonlinear and unstable monitoring data into trend and periodic terms, and an intelligent prediction model (CTG) suitable for river embankment deformation was proposed. The model used a polynomial function to predict the trend item, and a time convolution network-gated recurrent unit hybrid model combined with a particle swarm optimization algorithm (i.e., PSO-TCN-GRU algorithm) was used to predict the periodic term. It was found that the intelligent algorithm proposed is superior to other classical neural network prediction methods, and has a certain promotional value, which can provide reference for the deformation prediction of similar projects. In addition, it is suggested that data decomposition and feature extraction should be carried out before monitoring data prediction, which is conducive to improving the prediction results of the model.
2025, 39(5): 648-655.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0168
Abstract:
Reliable prediction of excavation deformation contributes to improved construction safety. The existing adaptive exponential smoothing method has been improved by abandoning the traditional approach of solving for the optimal smoothing coefficient α through exhaustive search. Instead, mean squared error (MSE) was used as the loss function, and the gradient expressions of MSE with respect to α for single, double, and triple exponential smoothing models were derived. Subsequently, the gradient descent method is applied to solve for the optimal α value. Compared to the original method, the improved method demonstrates comparable performance in optimal model selection and coefficient optimization, and significantly enhances optimization efficiency with appropriate hyper-parameter (especially learning rate) settings. Based on the application to 1900 sets of excavation deformation sequences, the applicability and reliability of the improved adaptive exponential smoothing method in deformation prediction have been systematically evaluated, and the effects of prediction step size and training sequence length on prediction performance have been explored. Consequently, an optimized scheme for excavation deformation prediction is proposed.
Reliable prediction of excavation deformation contributes to improved construction safety. The existing adaptive exponential smoothing method has been improved by abandoning the traditional approach of solving for the optimal smoothing coefficient α through exhaustive search. Instead, mean squared error (MSE) was used as the loss function, and the gradient expressions of MSE with respect to α for single, double, and triple exponential smoothing models were derived. Subsequently, the gradient descent method is applied to solve for the optimal α value. Compared to the original method, the improved method demonstrates comparable performance in optimal model selection and coefficient optimization, and significantly enhances optimization efficiency with appropriate hyper-parameter (especially learning rate) settings. Based on the application to 1900 sets of excavation deformation sequences, the applicability and reliability of the improved adaptive exponential smoothing method in deformation prediction have been systematically evaluated, and the effects of prediction step size and training sequence length on prediction performance have been explored. Consequently, an optimized scheme for excavation deformation prediction is proposed.
2025, 39(5): 656-666.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0165
Abstract:
Stratigraphic classification and soil type identification are the basis for the application of static cone penetrate test results. To achieve accurate stratigraphic classification based on static cone penetrate test data, a prediction method based on eXtreme Gradient Boosting (XGBoost) and Bayesian optimization (BO) was proposed. Using the XGBoost method, a dataset is constructed based on the static cone penetrate test data of a project in South China, the hyperparameters of the XGBoost model were optimised using Bayesian optimisation, and the optimal XGBoost model was constructed to classify and predict the stratigraphic categories. The classification prediction accuracies of the constructed XGBoost model on the training set and the test set are 100% and 96.46%, respectively. The prediction accuracies of the Bayesian-optimised support vector machine (SVM), k-nearest neighbor (KNN) and random forest (RF) models on the test set are 93.34%, 92.99% and 95.89%, respectively, which are lower than those of the XGBoost, proving the superior prediction performances of the XGBoost model. The constructed XGBoost model was used to predict the stratigraphic classification of two boreholes in a geotechnical engineering exploration project in South China, and the prediction accuracy reaches more than 95%, which indicates that the model has a very reliable application value for the stratigraphic classification of static cone penetrate test in the actual geotechnical engineering exploration practice.
Stratigraphic classification and soil type identification are the basis for the application of static cone penetrate test results. To achieve accurate stratigraphic classification based on static cone penetrate test data, a prediction method based on eXtreme Gradient Boosting (XGBoost) and Bayesian optimization (BO) was proposed. Using the XGBoost method, a dataset is constructed based on the static cone penetrate test data of a project in South China, the hyperparameters of the XGBoost model were optimised using Bayesian optimisation, and the optimal XGBoost model was constructed to classify and predict the stratigraphic categories. The classification prediction accuracies of the constructed XGBoost model on the training set and the test set are 100% and 96.46%, respectively. The prediction accuracies of the Bayesian-optimised support vector machine (SVM), k-nearest neighbor (KNN) and random forest (RF) models on the test set are 93.34%, 92.99% and 95.89%, respectively, which are lower than those of the XGBoost, proving the superior prediction performances of the XGBoost model. The constructed XGBoost model was used to predict the stratigraphic classification of two boreholes in a geotechnical engineering exploration project in South China, and the prediction accuracy reaches more than 95%, which indicates that the model has a very reliable application value for the stratigraphic classification of static cone penetrate test in the actual geotechnical engineering exploration practice.
2025, 39(5): 667-673.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0092
Abstract:
The stability of anchor foundation pit is the main control factor affecting the safety of suspension-bridge engineering. A suspension-bridge in Sichuan is located in a high-intensity earthquake area, which anchorage foundation pit is located in thick accumulation. The maximum slope height of the foundation pit slope is 110 meters. Taking the anchorage foundation pit project as an example, research is conducted on the long-term stability of a foundation pit over 100 meters deep on a thick accumulation. By conducting in-situ density tests, on-site shear tests, and deformation tests, the strength and deformation characteristics of the foundation pit soil were studied, and the physical and mechanical parameters of the foundation pit soil were obtained. The application of finite difference software for seismic simulation calculation of anchor foundation pit shows that deep accumulation foundation pit is prone to deformation and even sliding instability and failure under strong earthquakes. The maximum displacement of the slope is about 20 m, and the thickness of the slope instability range is about 15~23 m. Based on this, the two-level requirements for bridge foundation pit protection and comprehensive treatment measures of excavation pre-reinforcement, step-by-step excavation, and zoning protection are proposed. The dynamic and time-historical analysis method was used to verify the stability of the foundation pit under this treatment measure. The results show that the maximum displacement of the reinforced slope after 30 seconds of Wenchuan earthquake wave input was only 0.223 m. The monitoring data for 36 consecutive months after the excavation and support of the foundation pit show that the maximum displacement of the slope was less than 9.05 mm, which was basically consistent with the numerical calculation results, verifying the effectiveness of the reinforcement measures and numerical calculation methods.
The stability of anchor foundation pit is the main control factor affecting the safety of suspension-bridge engineering. A suspension-bridge in Sichuan is located in a high-intensity earthquake area, which anchorage foundation pit is located in thick accumulation. The maximum slope height of the foundation pit slope is 110 meters. Taking the anchorage foundation pit project as an example, research is conducted on the long-term stability of a foundation pit over 100 meters deep on a thick accumulation. By conducting in-situ density tests, on-site shear tests, and deformation tests, the strength and deformation characteristics of the foundation pit soil were studied, and the physical and mechanical parameters of the foundation pit soil were obtained. The application of finite difference software for seismic simulation calculation of anchor foundation pit shows that deep accumulation foundation pit is prone to deformation and even sliding instability and failure under strong earthquakes. The maximum displacement of the slope is about 20 m, and the thickness of the slope instability range is about 15~23 m. Based on this, the two-level requirements for bridge foundation pit protection and comprehensive treatment measures of excavation pre-reinforcement, step-by-step excavation, and zoning protection are proposed. The dynamic and time-historical analysis method was used to verify the stability of the foundation pit under this treatment measure. The results show that the maximum displacement of the reinforced slope after 30 seconds of Wenchuan earthquake wave input was only 0.223 m. The monitoring data for 36 consecutive months after the excavation and support of the foundation pit show that the maximum displacement of the slope was less than 9.05 mm, which was basically consistent with the numerical calculation results, verifying the effectiveness of the reinforcement measures and numerical calculation methods.
2025, 39(5): 674-679.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0170
Abstract:
The design of the support system of the deep foundation pit in the soft soil area is directly related to the safety and efficiency of the project. In the design of a deep and large foundation pit support in the soft soil area of Ningbo, the horizontal support adopts a super-large circular concrete support with a diameter of 180 m, and the vertical support uses the static drilling rooted pile as the column pile, which realizes the prefabrication of the factory. Compared with the conventional foundation pit support system, the innovative support system can reduce the support coverage area by up to 20%, and greatly reduce the impact of the support on the construction operation under the premise of ensuring the safety of the foundation pit. The application of special column pile greatly reduces the project cost. The comparative analysis of the numerical simulation results and the engineering measurement results shows that the three-dimensional finite element method can reasonably predict the deformation of the super-large diameter annular brace foundation pit, and the super-large diameter annular brace can meet the deformation control requirements of deep and large foundation pits in soft soil areas.
The design of the support system of the deep foundation pit in the soft soil area is directly related to the safety and efficiency of the project. In the design of a deep and large foundation pit support in the soft soil area of Ningbo, the horizontal support adopts a super-large circular concrete support with a diameter of 180 m, and the vertical support uses the static drilling rooted pile as the column pile, which realizes the prefabrication of the factory. Compared with the conventional foundation pit support system, the innovative support system can reduce the support coverage area by up to 20%, and greatly reduce the impact of the support on the construction operation under the premise of ensuring the safety of the foundation pit. The application of special column pile greatly reduces the project cost. The comparative analysis of the numerical simulation results and the engineering measurement results shows that the three-dimensional finite element method can reasonably predict the deformation of the super-large diameter annular brace foundation pit, and the super-large diameter annular brace can meet the deformation control requirements of deep and large foundation pits in soft soil areas.
2025, 39(5): 680-687.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0164
Abstract:
Due to space limitations, a slope project in Guiyang requires vertical excavation. Because the slope is adjacent to the original water plant buildings and structures, the slope deformation needs to be strictly controlled. Therefore, the inclined chair pile-anchor support system was proposed. Through numerical simulation, the stability of the slope after supporting, the displacement control during construction, and the stress characteristics of the support structure were discussed. The results show that the supporting system has reasonable stress and a good deformation control effect. The monitoring results show that the maximum cumulative displacement of each measuring point of the slope section is in a small range, the deformation is gradually stable, the inclinometer curve tends to converge, and the field treatment measures have obvious effects. After the completion of the slope project of the Eastern Water Plant, the operation status was good. On the premise of ensuring the site space, it effectively protected the safety of the existing water plant at the top of the slope. The inclined chair pile anchor support scheme adopted can be used as a reference for similar projects.
Due to space limitations, a slope project in Guiyang requires vertical excavation. Because the slope is adjacent to the original water plant buildings and structures, the slope deformation needs to be strictly controlled. Therefore, the inclined chair pile-anchor support system was proposed. Through numerical simulation, the stability of the slope after supporting, the displacement control during construction, and the stress characteristics of the support structure were discussed. The results show that the supporting system has reasonable stress and a good deformation control effect. The monitoring results show that the maximum cumulative displacement of each measuring point of the slope section is in a small range, the deformation is gradually stable, the inclinometer curve tends to converge, and the field treatment measures have obvious effects. After the completion of the slope project of the Eastern Water Plant, the operation status was good. On the premise of ensuring the site space, it effectively protected the safety of the existing water plant at the top of the slope. The inclined chair pile anchor support scheme adopted can be used as a reference for similar projects.
2025, 39(5): 688-692.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0210
Abstract:
The number of cross-project constructions where new subway lines undercross existing railways using shield tunneling is increasing with the urban comprehensive transportation construction. Previous studies have analyzed the impact of shield tunneling on railway deformation through numerical simulation and on-site monitoring, with tunnel depths generally below 20 m. Due to the time-space effect during tunnel construction, the influence of tunneling at depths exceeding 20 m on railway deformation characteristics remains unclear. This research takes the example of a highway shield tunnel undercrossing the Beijing-Guangzhou Railway in Wuhan city and uses automated monitoring methods to analyze the influence of deep-buried shield tunneling construction on the settlement of existing railway tracks, subgrades, and the inclination of the railway catenary system. The study revealed that for deep-buried shield tunneling construction, the deformations of the railway subgrades, tracks, and overhead contact system have a certain lag. The settlement troughs of the railway tracks and subgrades exhibit a V-shaped or U-shaped pattern, with an affected width of approximately 75 m, which is significantly larger than that of ordinary shallow-buried shield tunnels. The research findings can provide data support and reference for similar deep-buried shield tunneling projects that undercross existing railways.
The number of cross-project constructions where new subway lines undercross existing railways using shield tunneling is increasing with the urban comprehensive transportation construction. Previous studies have analyzed the impact of shield tunneling on railway deformation through numerical simulation and on-site monitoring, with tunnel depths generally below 20 m. Due to the time-space effect during tunnel construction, the influence of tunneling at depths exceeding 20 m on railway deformation characteristics remains unclear. This research takes the example of a highway shield tunnel undercrossing the Beijing-Guangzhou Railway in Wuhan city and uses automated monitoring methods to analyze the influence of deep-buried shield tunneling construction on the settlement of existing railway tracks, subgrades, and the inclination of the railway catenary system. The study revealed that for deep-buried shield tunneling construction, the deformations of the railway subgrades, tracks, and overhead contact system have a certain lag. The settlement troughs of the railway tracks and subgrades exhibit a V-shaped or U-shaped pattern, with an affected width of approximately 75 m, which is significantly larger than that of ordinary shallow-buried shield tunnels. The research findings can provide data support and reference for similar deep-buried shield tunneling projects that undercross existing railways.
2025, 39(5): 693-698.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0310
Abstract:
Combined with the engineering example of soft rock socketed pile in a high-rise building, the vertical bearing capacity of a single pile determined by rock uniaxial compressive strength test, in-situ plate load test, and single pile static load test was compared and analyzed. The results show that the standard value of the vertical ultimate bearing capacity of a single pile determined by the plate load test method is 1.51 times that of the rock uniaxial compressive strength method. According to the current local standard safety factor K, the characteristic value of the bearing capacity of a single pile determined by the plate load test has not been improved; The characteristic value of single pile bearing capacity obtained by the single pile static load method is 3.12 times that obtained by the rock uniaxial compressive strength method. According to the analysis results, the bearing capacity of a single pile determined by the rock uniaxial compressive strength method is conservative, and it is suggested to consider the influence of the confining pressure constraint effect. When the rock foundation load test method is used for calculation, it is suggested to adjust the value of the Chongqing local standard safety factor K.
Combined with the engineering example of soft rock socketed pile in a high-rise building, the vertical bearing capacity of a single pile determined by rock uniaxial compressive strength test, in-situ plate load test, and single pile static load test was compared and analyzed. The results show that the standard value of the vertical ultimate bearing capacity of a single pile determined by the plate load test method is 1.51 times that of the rock uniaxial compressive strength method. According to the current local standard safety factor K, the characteristic value of the bearing capacity of a single pile determined by the plate load test has not been improved; The characteristic value of single pile bearing capacity obtained by the single pile static load method is 3.12 times that obtained by the rock uniaxial compressive strength method. According to the analysis results, the bearing capacity of a single pile determined by the rock uniaxial compressive strength method is conservative, and it is suggested to consider the influence of the confining pressure constraint effect. When the rock foundation load test method is used for calculation, it is suggested to adjust the value of the Chongqing local standard safety factor K.
2025, 39(5): 699-708.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0336
Abstract:
To explore the applicability of the "bored pile+jet grouting pile" composite structure in the construction of PBA tunnel and reveal its mechanical effect, based on the engineering example of the underground excavation section of Dongsanlu Station to Tiantongyuan East Station of Beijing Rail Transit Line 13, the numerical simulation of the whole construction process of PBA tunnel under the support of the composite structure in confined water rich strata was carried out. The internal force and deformation of the composite structure under the key construction steps and the influence of its construction process on the surface settlement and formation of the plastic zone were analyzed, and the effects of pile diameter, pile insertion ratio, and pile interlocking on its mechanical performance were discussed. The results show that: (1) The construction stage of the composite structure has little effect on the surface settlement trough and formation plastic zone; (2) The composite structure mainly appears horizontal lateral displacement towards the inner side of the tunnel during the construction of the tunnel. The overall lateral displacement is in the form of a quadratic curve along the depth direction. The maximum lateral displacement occurs in the middle of the jet grouting pile and the upper part of the bored pile, and the lateral displacement below the bottom plate is small; (3) After the excavation of the main tunnel, the axial forces of bored piles and jet grouting piles are evenly distributed in the free section of the excavation of the main tunnel, the axial forces and bending moments are sharply reduced below the bottom plate, and the maximum axial forces and bending moments are located near the bottom plate.
To explore the applicability of the "bored pile+jet grouting pile" composite structure in the construction of PBA tunnel and reveal its mechanical effect, based on the engineering example of the underground excavation section of Dongsanlu Station to Tiantongyuan East Station of Beijing Rail Transit Line 13, the numerical simulation of the whole construction process of PBA tunnel under the support of the composite structure in confined water rich strata was carried out. The internal force and deformation of the composite structure under the key construction steps and the influence of its construction process on the surface settlement and formation of the plastic zone were analyzed, and the effects of pile diameter, pile insertion ratio, and pile interlocking on its mechanical performance were discussed. The results show that: (1) The construction stage of the composite structure has little effect on the surface settlement trough and formation plastic zone; (2) The composite structure mainly appears horizontal lateral displacement towards the inner side of the tunnel during the construction of the tunnel. The overall lateral displacement is in the form of a quadratic curve along the depth direction. The maximum lateral displacement occurs in the middle of the jet grouting pile and the upper part of the bored pile, and the lateral displacement below the bottom plate is small; (3) After the excavation of the main tunnel, the axial forces of bored piles and jet grouting piles are evenly distributed in the free section of the excavation of the main tunnel, the axial forces and bending moments are sharply reduced below the bottom plate, and the maximum axial forces and bending moments are located near the bottom plate.
2025, 39(5): 709-715.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0338
Abstract:
With the continuous growth of the economy, some existing tunnels are no longer able to meet the current transportation needs. To ensure smooth and safe traffic, it is necessary to carry out reasonable renovation and expansion projects on the tunnel. This research is based on the ABAQUS finite element software to establish a three-dimensional model of the tunnel surrounding rock lining. The excavation process of the tunnel was simulated using the life and death element method. The stress-strain cloud map of the surrounding rock and the distribution characteristics of the plastic zone of the lining were obtained for each step, and the results before and after were compared and analyzed. The weak stress areas of the tunnel structure were determined, and the mechanical behavior of the structure during the excavation process was predicted in advance. The results revealed that the construction process adopted in this project is safe and reasonable, the tunnel structure performs well in mechanical properties, and the safety and economy of the project are guaranteed.
With the continuous growth of the economy, some existing tunnels are no longer able to meet the current transportation needs. To ensure smooth and safe traffic, it is necessary to carry out reasonable renovation and expansion projects on the tunnel. This research is based on the ABAQUS finite element software to establish a three-dimensional model of the tunnel surrounding rock lining. The excavation process of the tunnel was simulated using the life and death element method. The stress-strain cloud map of the surrounding rock and the distribution characteristics of the plastic zone of the lining were obtained for each step, and the results before and after were compared and analyzed. The weak stress areas of the tunnel structure were determined, and the mechanical behavior of the structure during the excavation process was predicted in advance. The results revealed that the construction process adopted in this project is safe and reasonable, the tunnel structure performs well in mechanical properties, and the safety and economy of the project are guaranteed.
2025, 39(5): 716-723.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0344
Abstract:
Based on the reconstruction and expansion project of the existing Danjiashao tunnel, and considering the actual distribution law of the defects after the lining of the existing tunnel, the influence of different distribution positions and sizes of the cavities behind the lining on the response law of structural blasting vibration under various surrounding rock conditions was studied. The results show that the influence of the cavity behind the lining on the vibration response of the existing tunnel lining is different under different distribution positions, various sizes, and surrounding rock conditions. From the analysis of the distribution position of the cavity, the amplification effect of the cavity behind the vault lining on the vibration velocity and stress is greater than that of the arch waist cavity; from the analysis of the distribution size of the cavity, the larger the cavity is, the greater the amplification effect on the vibration velocity is, and the amplification effect on the stress is the opposite. From the analysis of the existence of voids behind the lining under different surrounding rock levels, the worse the surrounding rock (the higher the surrounding rock level), the more significant the amplification effect of the cavity on the vibration velocity and stress. The comprehensive analysis suggests that when the vibration velocity is used as the safety control reference value of the adjacent cavity tunnel during the blasting construction of the new tunnel, the vibration velocity control value at the cavity should be appropriately reduced according to the location, size, and surrounding rock condition of the cavity.
Based on the reconstruction and expansion project of the existing Danjiashao tunnel, and considering the actual distribution law of the defects after the lining of the existing tunnel, the influence of different distribution positions and sizes of the cavities behind the lining on the response law of structural blasting vibration under various surrounding rock conditions was studied. The results show that the influence of the cavity behind the lining on the vibration response of the existing tunnel lining is different under different distribution positions, various sizes, and surrounding rock conditions. From the analysis of the distribution position of the cavity, the amplification effect of the cavity behind the vault lining on the vibration velocity and stress is greater than that of the arch waist cavity; from the analysis of the distribution size of the cavity, the larger the cavity is, the greater the amplification effect on the vibration velocity is, and the amplification effect on the stress is the opposite. From the analysis of the existence of voids behind the lining under different surrounding rock levels, the worse the surrounding rock (the higher the surrounding rock level), the more significant the amplification effect of the cavity on the vibration velocity and stress. The comprehensive analysis suggests that when the vibration velocity is used as the safety control reference value of the adjacent cavity tunnel during the blasting construction of the new tunnel, the vibration velocity control value at the cavity should be appropriately reduced according to the location, size, and surrounding rock condition of the cavity.
2025, 39(5): 724-730.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0430
Abstract:
Karst breccia is a special type of sedimentary rock with a unique diagenetic environment and characteristics. Especially the karst breccia located on the slope of the canyon bank, under favorable groundwater discharge conditions, the later karst process will further deteriorate the mechanical properties of the rock mass and affect the stability of the foundation and the overall stability of the bank slope. Therefore, the suitability evaluation of the foundation of canyon bank slope composed of karst breccia for super large bridges is particularly crucial and important, which determines the type and scale of bridge structure based on this in engineering construction. This article takes the bank slope of the Lishui Grand Bridge Canyon on the Zhangjiajie Huayuan Expressway as the engineering background, and the structural characteristics and karst development characteristics of karst breccia have been revealed through adits and drilling surveys. Through overall slope reliability analysis, it has been demonstrated that the probability of deformation and failure of the bank slope under design loads exceeds 20%. According to a comprehensive engineering geological analysis, the karst breccia on the Zhangjiajie shore is not suitable as the foundation for the suspension bridge tower. Thus, a geological decision was made to adjust the cable bent tower to a dolomite conglomerate with better mechanical properties. This research has ensured the completion and opening of the Lishui Extra Large Bridge and provided new important references for the survey and design of super large bridges crossing canyons.
Karst breccia is a special type of sedimentary rock with a unique diagenetic environment and characteristics. Especially the karst breccia located on the slope of the canyon bank, under favorable groundwater discharge conditions, the later karst process will further deteriorate the mechanical properties of the rock mass and affect the stability of the foundation and the overall stability of the bank slope. Therefore, the suitability evaluation of the foundation of canyon bank slope composed of karst breccia for super large bridges is particularly crucial and important, which determines the type and scale of bridge structure based on this in engineering construction. This article takes the bank slope of the Lishui Grand Bridge Canyon on the Zhangjiajie Huayuan Expressway as the engineering background, and the structural characteristics and karst development characteristics of karst breccia have been revealed through adits and drilling surveys. Through overall slope reliability analysis, it has been demonstrated that the probability of deformation and failure of the bank slope under design loads exceeds 20%. According to a comprehensive engineering geological analysis, the karst breccia on the Zhangjiajie shore is not suitable as the foundation for the suspension bridge tower. Thus, a geological decision was made to adjust the cable bent tower to a dolomite conglomerate with better mechanical properties. This research has ensured the completion and opening of the Lishui Extra Large Bridge and provided new important references for the survey and design of super large bridges crossing canyons.
2025, 39(5): 731-736.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0478
Abstract:
The dynamic compaction method is widely used in coastal soft soil areas because of its convenient construction and low cost. In Beijing, affected by the heavy rainfall on July 31, 2023, some residential buildings in mountainous areas were seriously damaged by water. The newly built houses are two-story western-style houses with low bearing capacity demand. The project site is a terrace site at the front of the mountain. The dynamic compaction method was selected for foundation treatment, and the effect of dynamic compaction in the gravel-filled area was analyzed. Relying on the water-damaged reconstruction project of Yanhekou village, Zhaitang town, Mentougou District, the effect of dynamic compaction is simulated by using numerical calculation software. Combined with the actual engineering construction and testing data, the factors such as filling depth, rammer spacing, rammer size, and tamping times were analyzed, and the correction coefficient of dynamic compaction influence depth corresponding to the gravel filling stratum and the optimal location of tamping points in the stepped site were obtained. The numerical model calculation results are consistent with the field test results.
The dynamic compaction method is widely used in coastal soft soil areas because of its convenient construction and low cost. In Beijing, affected by the heavy rainfall on July 31, 2023, some residential buildings in mountainous areas were seriously damaged by water. The newly built houses are two-story western-style houses with low bearing capacity demand. The project site is a terrace site at the front of the mountain. The dynamic compaction method was selected for foundation treatment, and the effect of dynamic compaction in the gravel-filled area was analyzed. Relying on the water-damaged reconstruction project of Yanhekou village, Zhaitang town, Mentougou District, the effect of dynamic compaction is simulated by using numerical calculation software. Combined with the actual engineering construction and testing data, the factors such as filling depth, rammer spacing, rammer size, and tamping times were analyzed, and the correction coefficient of dynamic compaction influence depth corresponding to the gravel filling stratum and the optimal location of tamping points in the stepped site were obtained. The numerical model calculation results are consistent with the field test results.
2025, 39(5): 737-743.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0232
Abstract:
The anti-sliding bearing capacity, shear-slip failure characteristics, and mechanism of cantilever retaining walls placed on the protective layer of three waterproofing practices were studied through indoor large-scale shear tests and creep-stress relaxation coupled tests. Experimental results revealed that shear deformation, obvious deformation, and failure occur at the contact between the base plate of the cantilever retaining wall structure and the waterproof layer, and two forms mainly occur: slip failure and peeling failure. The shear deformation failure process of the cantilever retaining wall structure includes three stages: deformation, slippage, and peeling. The influence of different waterproof layers on the horizontal displacement and anti-slip bearing capacity of the upper retaining wall is obvious. The basement friction coefficient of the retaining wall on the waterproof layer is between 0.1 and 0.2, and compared with the conventional rock foundation retaining wall, the basement friction coefficient of the retaining wall is significantly smaller, and the horizontal displacement is large.
The anti-sliding bearing capacity, shear-slip failure characteristics, and mechanism of cantilever retaining walls placed on the protective layer of three waterproofing practices were studied through indoor large-scale shear tests and creep-stress relaxation coupled tests. Experimental results revealed that shear deformation, obvious deformation, and failure occur at the contact between the base plate of the cantilever retaining wall structure and the waterproof layer, and two forms mainly occur: slip failure and peeling failure. The shear deformation failure process of the cantilever retaining wall structure includes three stages: deformation, slippage, and peeling. The influence of different waterproof layers on the horizontal displacement and anti-slip bearing capacity of the upper retaining wall is obvious. The basement friction coefficient of the retaining wall on the waterproof layer is between 0.1 and 0.2, and compared with the conventional rock foundation retaining wall, the basement friction coefficient of the retaining wall is significantly smaller, and the horizontal displacement is large.
2025, 39(5): 744-751.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0289
Abstract:
Reinforcement materials were usually used in the structure to ensure the foundation's stability and improve the tensile strength of the soil. The scrap tire grille was proposed as a new material for foundation reinforcement based on tensile resistance and interface roughness. The influence of different overburden loads, packing compaction degree, tire strip width, and mesh size on the bearing capacity of reinforced tire silt was studied by drawing test. The results show that the bearing capacity of reinforced tire silt increases with the overlying load. The denser the fine-grained soil filler is, the greater the peak pulling force of the tire strip is. Strip width has the most obvious effect on the reinforcement effect of silt soil foundation. When strip width increases by 2 cm, the peak pulling force increases by nearly 50%. The bearing capacity decreases with the mesh size increases. The results show that the scrap tire grille can improve the bearing capacity of silt soil foundation effectively and enhance the tensile strength of soil. The research provides a reference for further theoretical research and technical application.
Reinforcement materials were usually used in the structure to ensure the foundation's stability and improve the tensile strength of the soil. The scrap tire grille was proposed as a new material for foundation reinforcement based on tensile resistance and interface roughness. The influence of different overburden loads, packing compaction degree, tire strip width, and mesh size on the bearing capacity of reinforced tire silt was studied by drawing test. The results show that the bearing capacity of reinforced tire silt increases with the overlying load. The denser the fine-grained soil filler is, the greater the peak pulling force of the tire strip is. Strip width has the most obvious effect on the reinforcement effect of silt soil foundation. When strip width increases by 2 cm, the peak pulling force increases by nearly 50%. The bearing capacity decreases with the mesh size increases. The results show that the scrap tire grille can improve the bearing capacity of silt soil foundation effectively and enhance the tensile strength of soil. The research provides a reference for further theoretical research and technical application.
2025, 39(5): 752-759.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0308
Abstract:
Post-grouting is a widely used pile foundation reinforcement technology in high-rise and large-span buildings. Many engineering practices have verified that this technology can effectively improve the bearing capacity of pile foundations. According to the construction needs of a project in Chengdu, Sichuan, two sets of static load tests were conducted on four post-grouting rotary drilled piles. Based on the test results, numerical simulations were used to study the stress and displacement distributions of the test piles under different grouting conditions, and the effects of the amount of grout injected into the pile side and pile end on the bearing capacity of the foundation were further investigated. The results show that the rotary drilled pile reinforced by post grouting technology has high bearing capacity and safety reserves. The side grouting of the pile mainly drives a larger range of rock mass on the pile side to participate in bearing the load through side resistance and the compression effect at the bottom of the grouting body, reducing the deformation and settlement of the pile body; Grouting at the pile tip can form a high-strength grouting body, improving the stress transmission state at the pile end, thereby preventing the rock mass at the pile end from yielding under compression and reducing its deformation; Changing the length of grouting at the pile side and the thickness of grouting at the pile end can affect the ultimate bearing capacity of the foundation, and the effect of the thickness at the pile end is more significant.
Post-grouting is a widely used pile foundation reinforcement technology in high-rise and large-span buildings. Many engineering practices have verified that this technology can effectively improve the bearing capacity of pile foundations. According to the construction needs of a project in Chengdu, Sichuan, two sets of static load tests were conducted on four post-grouting rotary drilled piles. Based on the test results, numerical simulations were used to study the stress and displacement distributions of the test piles under different grouting conditions, and the effects of the amount of grout injected into the pile side and pile end on the bearing capacity of the foundation were further investigated. The results show that the rotary drilled pile reinforced by post grouting technology has high bearing capacity and safety reserves. The side grouting of the pile mainly drives a larger range of rock mass on the pile side to participate in bearing the load through side resistance and the compression effect at the bottom of the grouting body, reducing the deformation and settlement of the pile body; Grouting at the pile tip can form a high-strength grouting body, improving the stress transmission state at the pile end, thereby preventing the rock mass at the pile end from yielding under compression and reducing its deformation; Changing the length of grouting at the pile side and the thickness of grouting at the pile end can affect the ultimate bearing capacity of the foundation, and the effect of the thickness at the pile end is more significant.
2025, 39(5): 760-765.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0312
Abstract:
The ϕ50 drill pipe is increasingly being used in standard penetration tests. However, there is no clear guidance in the specifications on whether and how to convert the blow count N value of the standard penetration tests obtained by the ϕ50 drill pipe when distinguishing the characteristics of rock and soil engineering. A comparative study was conducted on standard penetration tests with different drill pipe diameters at a site in Zhanjiang City. Statistical analysis was conducted on the relevant data, and the results showed that there was a significant correlation between the blow count of standard penetration tests and the drill pipe diameter, and the ratio of blow counts between different drill pipe diameters was related to the soil type and test depth. The blow counts of the ϕ42 drill pipe in sandy soil formations is less than that of the ϕ50 drill pipe, with an overall ratio of 0.89. The ratio of the two at different depths ranges from 0.83 to 1.01. As the test depth increases, the ratio of the blow counts shows a trend of first increasing and then decreasing. The blow counts of the ϕ42 drill pipe in the cohesive soil layer is greater than that of the ϕ50 drill pipe, and the overall ratio of the two is 1.14. The ratio of the two at different depths is 1.11~1.20. As the test depth increases, the ratio of the blow counts remains basically unchanged. The research results can provide reference for regional experience accumulation and engineering practice.
The ϕ50 drill pipe is increasingly being used in standard penetration tests. However, there is no clear guidance in the specifications on whether and how to convert the blow count N value of the standard penetration tests obtained by the ϕ50 drill pipe when distinguishing the characteristics of rock and soil engineering. A comparative study was conducted on standard penetration tests with different drill pipe diameters at a site in Zhanjiang City. Statistical analysis was conducted on the relevant data, and the results showed that there was a significant correlation between the blow count of standard penetration tests and the drill pipe diameter, and the ratio of blow counts between different drill pipe diameters was related to the soil type and test depth. The blow counts of the ϕ42 drill pipe in sandy soil formations is less than that of the ϕ50 drill pipe, with an overall ratio of 0.89. The ratio of the two at different depths ranges from 0.83 to 1.01. As the test depth increases, the ratio of the blow counts shows a trend of first increasing and then decreasing. The blow counts of the ϕ42 drill pipe in the cohesive soil layer is greater than that of the ϕ50 drill pipe, and the overall ratio of the two is 1.14. The ratio of the two at different depths is 1.11~1.20. As the test depth increases, the ratio of the blow counts remains basically unchanged. The research results can provide reference for regional experience accumulation and engineering practice.
2025, 39(5): 766-774.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0399
Abstract:
To further improve the energy absorption and shock absorption effects of foam light soil and enhance engineering safety, a novel Highly Elastic Polymer Fiber (HEPF) fluid-solidified lightweight soil material was developed. A series of tests were conducted to analyze its water stability, impermeability, freeze-thaw resistance, and fatigue loading characteristics. The test results show that HEPF fluid-solidified light soil, containing high elastic polymer and fiber, offers significant advantages in improving water stability, water permeability resistance, and frost resistance compared to common foam light soil. When the content of high-elastic polymer is 10% and the fiber content is 0.2%, the water stability coefficient exceeds 0.98, the seepage pressure increases by 50% to 150% compared to the control group, and the frost resistance coefficient significantly improves. Additionally, the material demonstrated good durability and crack resistance in fatigue loading tests, effectively extending its service life. The research findings validate the superior performance of HEPF fluid-solidified light soil in engineering applications, confirming its good durability and environmental adaptability under harsh conditions, such as traffic loads and cyclic vibrations.
To further improve the energy absorption and shock absorption effects of foam light soil and enhance engineering safety, a novel Highly Elastic Polymer Fiber (HEPF) fluid-solidified lightweight soil material was developed. A series of tests were conducted to analyze its water stability, impermeability, freeze-thaw resistance, and fatigue loading characteristics. The test results show that HEPF fluid-solidified light soil, containing high elastic polymer and fiber, offers significant advantages in improving water stability, water permeability resistance, and frost resistance compared to common foam light soil. When the content of high-elastic polymer is 10% and the fiber content is 0.2%, the water stability coefficient exceeds 0.98, the seepage pressure increases by 50% to 150% compared to the control group, and the frost resistance coefficient significantly improves. Additionally, the material demonstrated good durability and crack resistance in fatigue loading tests, effectively extending its service life. The research findings validate the superior performance of HEPF fluid-solidified light soil in engineering applications, confirming its good durability and environmental adaptability under harsh conditions, such as traffic loads and cyclic vibrations.
2025, 39(5): 775-781.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0340
Abstract:
A series of cyclic triaxial tests were conducted on Zhoushan undrained marine soft clay with dynamic triaxial instrument to analyze the effects of cyclic loads such as wind and waves on the stiffness degradation characteristics of normally consolidated soft clay. The test results show that the weakening law of soil dynamic modulus closely correlates with CSR. Before the critical cyclic stress ratio CSR is reached, the double-amplitude axial strain$ \varepsilon\mathrm{_{DA}} $ increases linearly with the number of cycles. When the CSR is greater than the critical CSR, the stiffness of the sample degrades significantly with the increase of the number of cycles, so that the soil sample was destroyed. It was found that the influence of different confining pressures on the cyclic weakening of dynamic modulus was effectively captured by CSR. Based on the experimental rules, an empirical formula for soil stiffness variation with the number of cycles, cyclic stress amplitude and confining pressure was established. The stiffness attenuation model of marine soft clay was implemented in the numerical model by using ABAQUS subroutine USDFLD. The research results can provide a reference for the numerical simulation of the bearing performance of offshore wind turbines under long-term cyclic load conditions.
A series of cyclic triaxial tests were conducted on Zhoushan undrained marine soft clay with dynamic triaxial instrument to analyze the effects of cyclic loads such as wind and waves on the stiffness degradation characteristics of normally consolidated soft clay. The test results show that the weakening law of soil dynamic modulus closely correlates with CSR. Before the critical cyclic stress ratio CSR is reached, the double-amplitude axial strain
2025, 39(5): 782-790.
doi: 10.20265/j.cnki.issn.1007-2993.2024-0402
Abstract:
To study the influence of pore spacing and pore diameter on the deformation and failure of rocks with uniformly distributed pores, a set of microscopic parameters was determined by using the indoor uniaxial compression test data of complete sandstone specimens and sandstone specimens with prefabricated single cracks and discrete element particle flow software simulation, and the uniaxial compression simulation test of sandstone specimens with uniformly distributed pores was carried out based on the microscopic parameters. The research results indicate that when the pore diameter is kept constant, the peak stress, crack initiation stress and elastic modulus of the specimen all show a decreasing trend with the decrease of pore spacing, and the failure form of the specimen changes from shear failure to splitting failure; when the pore spacing is kept constant, the peak stress, crack initiation stress and elastic modulus of the specimen show a decreasing trend with the increase of pore diameter, and the failure form of the specimen changes from splitting shear composite failure to shear failure; the failure of the specimen starts from the stress concentration around the pore, and finally, the cracks extend and penetrate due to the fracture of particle bonding. Notably, the tensile cracks of the specimen are significantly more than the shear cracks.
To study the influence of pore spacing and pore diameter on the deformation and failure of rocks with uniformly distributed pores, a set of microscopic parameters was determined by using the indoor uniaxial compression test data of complete sandstone specimens and sandstone specimens with prefabricated single cracks and discrete element particle flow software simulation, and the uniaxial compression simulation test of sandstone specimens with uniformly distributed pores was carried out based on the microscopic parameters. The research results indicate that when the pore diameter is kept constant, the peak stress, crack initiation stress and elastic modulus of the specimen all show a decreasing trend with the decrease of pore spacing, and the failure form of the specimen changes from shear failure to splitting failure; when the pore spacing is kept constant, the peak stress, crack initiation stress and elastic modulus of the specimen show a decreasing trend with the increase of pore diameter, and the failure form of the specimen changes from splitting shear composite failure to shear failure; the failure of the specimen starts from the stress concentration around the pore, and finally, the cracks extend and penetrate due to the fracture of particle bonding. Notably, the tensile cracks of the specimen are significantly more than the shear cracks.
2017, 31(3): 153-159,163.
doi: 10.3969/j.issn.1007-2993.2017.03.010
摘要：
将边坡稳定性分析的方法分为确定性分析方法(以瑞典圆弧法、简化Bishop法等为代表的极限平衡法和以有限元法、有限差分法等为代表的数值分析方法)和非确定性方法(可靠度法、模糊综合判断法、灰色系统法、人工智能法等),详述了各分析方法的原理、优缺点以及适用性,并对其中一些方法进行了比较分析,提出了岩土边坡系统稳定性评价的发展方向。
将边坡稳定性分析的方法分为确定性分析方法(以瑞典圆弧法、简化Bishop法等为代表的极限平衡法和以有限元法、有限差分法等为代表的数值分析方法)和非确定性方法(可靠度法、模糊综合判断法、灰色系统法、人工智能法等),详述了各分析方法的原理、优缺点以及适用性,并对其中一些方法进行了比较分析,提出了岩土边坡系统稳定性评价的发展方向。
2020, 34(3): 143-149.
doi: 10.3969/j.issn.1007-2993.2020.03.005
摘要：
有限元软件数值模拟是现在从业人员分析敏感环境下基坑工程的重要手段，选择合适的本构模型是其关键。为了解工程中常用的三种土的本构模型适宜性，运用三维有限元软件Midas GTS NX模拟了某大型深基坑开挖过程，将采用不同本构模型的数值模拟结果与基坑监测结果进行对比，进而分析本构模型的适用性。可为本区类似工程进行有限元数值模拟分析时提供参考和借鉴。
有限元软件数值模拟是现在从业人员分析敏感环境下基坑工程的重要手段，选择合适的本构模型是其关键。为了解工程中常用的三种土的本构模型适宜性，运用三维有限元软件Midas GTS NX模拟了某大型深基坑开挖过程，将采用不同本构模型的数值模拟结果与基坑监测结果进行对比，进而分析本构模型的适用性。可为本区类似工程进行有限元数值模拟分析时提供参考和借鉴。
2016, 30(2): 85-88.
doi: 10.3969/j.issn.1007-2993.2016.02.007
摘要：
BIM技术具有三维可视化、碰撞检测、工程信息管理等众多特点,极大地提升了工程质量与效率,在建筑领域得到迅猛发展,然而在岩土工程中因为收费机制、软件功能限制、应用局限性等原因导致其发展的严重滞后。随着设计可视化、信息化发展进程,BIM也将在岩土中得到立足。对BIM在岩土中的应用现状进行了剖析,并对发展前景展望。以武汉亚洲医院基坑项目为依托,进行了BIM的完整实施,探讨了模型建立方式与施工应用方法,对今后BIM在岩土工程中的应用推广具有一定指导意义。
BIM技术具有三维可视化、碰撞检测、工程信息管理等众多特点,极大地提升了工程质量与效率,在建筑领域得到迅猛发展,然而在岩土工程中因为收费机制、软件功能限制、应用局限性等原因导致其发展的严重滞后。随着设计可视化、信息化发展进程,BIM也将在岩土中得到立足。对BIM在岩土中的应用现状进行了剖析,并对发展前景展望。以武汉亚洲医院基坑项目为依托,进行了BIM的完整实施,探讨了模型建立方式与施工应用方法,对今后BIM在岩土工程中的应用推广具有一定指导意义。
2016, 30(1): 6-11.
doi: 10.3969/j.issn.1007-2993.2016.01.002
摘要：
探讨了BIM在岩土工程勘察领域应用的可行性,根据多年的研究和工程实践,提出了BIM技术应用于岩土工程勘察领域的目标、实现途径和分阶段的解决方案。
探讨了BIM在岩土工程勘察领域应用的可行性,根据多年的研究和工程实践,提出了BIM技术应用于岩土工程勘察领域的目标、实现途径和分阶段的解决方案。
2018, 32(4): 189-193,198.
doi: 10.3969/j.issn.1007-2993.2018.04.006
摘要：
上海市城市道路发生的地面塌陷主要原因为浅部砂层分布区域地下排水管线渗漏引发流砂,导致地下土体流失,地表硬壳层承载力下降。将有限元和离散元二者进行耦合,从管线渗漏位置和对邻近管线影响两个方面诱发地下空洞机理进行数值模拟研究。研究结果表明,管道表面顶部局部渗漏引起地表以下土体流失量最大,底部渗漏造成的影响范围较小;管道断裂渗漏引起的地面塌陷范围比管道局部渗漏大得多,但深度较管道顶部局部渗漏引起的塌陷深度小;邻近管道埋深越大,地表以下土体流失量越大,引起塌陷影响区域范围越大,而埋深较浅时,其所受邻近渗漏管道的影响较大;在对地面塌陷进行监测与预防时,不应仅关注地表沉降变形,关注管道周边的土体变形是一种更加及时有效的方法。
上海市城市道路发生的地面塌陷主要原因为浅部砂层分布区域地下排水管线渗漏引发流砂,导致地下土体流失,地表硬壳层承载力下降。将有限元和离散元二者进行耦合,从管线渗漏位置和对邻近管线影响两个方面诱发地下空洞机理进行数值模拟研究。研究结果表明,管道表面顶部局部渗漏引起地表以下土体流失量最大,底部渗漏造成的影响范围较小;管道断裂渗漏引起的地面塌陷范围比管道局部渗漏大得多,但深度较管道顶部局部渗漏引起的塌陷深度小;邻近管道埋深越大,地表以下土体流失量越大,引起塌陷影响区域范围越大,而埋深较浅时,其所受邻近渗漏管道的影响较大;在对地面塌陷进行监测与预防时,不应仅关注地表沉降变形,关注管道周边的土体变形是一种更加及时有效的方法。
2016, 30(1): 12-19,38.
doi: 10.3969/j.issn.1007-2993.2016.01.003
摘要：
黄土丘陵沟壑区高填方工程的地形地貌和地质环境复杂,场地内常分布有大面积湿陷性黄土和淤积土,且具有土方量大、影响因素多、施工工期紧、沉降控制要求高等特点,建设过程面临着填方体的稳定、变形、排水、湿化变形控制及边坡防护等问题。以国内几处典型黄土高填方工程为例,介绍了通过场地综合地质条件评价、土方平衡优化、地下盲沟排水、原地基强夯加固处理、填筑体压(夯)实处理、填挖边坡防护处理、施工质量立体式监控、岩土工程全程监测等多种手段有效组合,解决黄土高填方工程问题的实践工作,相关经验可供类似工程借鉴。
黄土丘陵沟壑区高填方工程的地形地貌和地质环境复杂,场地内常分布有大面积湿陷性黄土和淤积土,且具有土方量大、影响因素多、施工工期紧、沉降控制要求高等特点,建设过程面临着填方体的稳定、变形、排水、湿化变形控制及边坡防护等问题。以国内几处典型黄土高填方工程为例,介绍了通过场地综合地质条件评价、土方平衡优化、地下盲沟排水、原地基强夯加固处理、填筑体压(夯)实处理、填挖边坡防护处理、施工质量立体式监控、岩土工程全程监测等多种手段有效组合,解决黄土高填方工程问题的实践工作,相关经验可供类似工程借鉴。
2019, 33(2): 84-88.
doi: 10.3969/j.issn.1007-2993.2019.02.006
摘要：
总结分析了建筑工程肥槽回填土质量不良引发的常见工程问题，以及肥槽回填土不易施工密实的几个主要原因，并总结提出了各种肥槽回填土处理方法，以及它们主要的适用条件。
总结分析了建筑工程肥槽回填土质量不良引发的常见工程问题，以及肥槽回填土不易施工密实的几个主要原因，并总结提出了各种肥槽回填土处理方法，以及它们主要的适用条件。
3D Laser Scanning Technology and BIM Technology in Ancient Building Protection Surveying and Mapping
2019, 33(4): 222-225.
doi: 10.3969/j.issn.1007-2993.2019.04.008
摘要：
结合北京市密云区古北口村文物建筑群工程实例介绍了三维激光扫描技术、BIM（建筑信息模型）在古建筑测绘中的应用。通过对比传统测绘方法，证明其在测绘及文物保护方面应用的优势。
结合北京市密云区古北口村文物建筑群工程实例介绍了三维激光扫描技术、BIM（建筑信息模型）在古建筑测绘中的应用。通过对比传统测绘方法，证明其在测绘及文物保护方面应用的优势。
2019, 33(2): 115-120.
doi: 10.3969/j.issn.1007-2993.2019.02.013
摘要：
针对珠海地区的深厚软基，采用真空联合堆载预压法进行加固处理。在施工过程中对软基的地表沉降、膜下真空度、孔隙水压力、深层水平位移等进行监测，得到了真空预压加固软土地基的随时间变化曲线。软基处理完成后对原状土进行原位十字板剪切试验和载荷试验，并取土进行室内土工试验。监测和检测试验分析表明：加固后土的物理力学性质有了明显提高，地基加固效果较好，其影响深度达到25～30 m，在15～20 m范围内加固效果最为显著; 但真空预压并未改变软土的触变性，加固后的软土仍应避免扰动。
针对珠海地区的深厚软基，采用真空联合堆载预压法进行加固处理。在施工过程中对软基的地表沉降、膜下真空度、孔隙水压力、深层水平位移等进行监测，得到了真空预压加固软土地基的随时间变化曲线。软基处理完成后对原状土进行原位十字板剪切试验和载荷试验，并取土进行室内土工试验。监测和检测试验分析表明：加固后土的物理力学性质有了明显提高，地基加固效果较好，其影响深度达到25～30 m，在15～20 m范围内加固效果最为显著; 但真空预压并未改变软土的触变性，加固后的软土仍应避免扰动。
2017, 31(1): 49-54.
doi: 10.3969/j.issn.1007-2993.2017.01.012
摘要：
为了研究邕江北岸Ⅱ级阶地地区浅埋大断面(6.9 m×4.9 m)矩形顶管在复杂环境下长距离掘进过程中的地表沉降规律及控制措施,依托南宁地铁1号线金湖广场站Ⅲ号出入口工程,采用三维有限差分软件FLAC3D模拟顶管施工过程,并与实际监测结果作对比验证,结果表明:①在顶进过程中顶管机前方土体的主要扰动范围为两倍洞宽;②地表横向沉降曲线以顶管轴线为中心呈正态分布,地表沉降的横向影响范围为三倍洞宽;③通过顶管机头上抬、加设注浆套板、管节减摩注浆以及合理的顶进参数,确保地表隆起和沉降量均在合理控制的范围内。
为了研究邕江北岸Ⅱ级阶地地区浅埋大断面(6.9 m×4.9 m)矩形顶管在复杂环境下长距离掘进过程中的地表沉降规律及控制措施,依托南宁地铁1号线金湖广场站Ⅲ号出入口工程,采用三维有限差分软件FLAC3D模拟顶管施工过程,并与实际监测结果作对比验证,结果表明:①在顶进过程中顶管机前方土体的主要扰动范围为两倍洞宽;②地表横向沉降曲线以顶管轴线为中心呈正态分布,地表沉降的横向影响范围为三倍洞宽;③通过顶管机头上抬、加设注浆套板、管节减摩注浆以及合理的顶进参数,确保地表隆起和沉降量均在合理控制的范围内。
2021, 35(4): 269-274.
doi: 10.3969/j.issn.1007-2993.2021.04.012
Abstract:
2023, 37(5): 505-517.
doi: 10.3969/j.issn.1007-2993.2023.05.001
Abstract:
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ISSN：1007-2993
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