岩土工程技术

2025, 39(2): 1-1.

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2025, 39(2): 1-3.

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Digital management platform for marine survey based on GIS+BIM+digital twin technology

Wang Xiaowei, Wang Zhang, Xu Siyi

2025, 39(2): 159-166. doi: 10.20265/j.cnki.issn.1007-2993.2024-0243

[Abstract](146) [FullText HTML] (23) [PDF 2232KB](30)

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Given the problems of wide scope, high risk, difficult scheduling, mixed information, and difficult understanding of marine engineering, GIS (geographic information System), BIM (building information model), digital twin, IoT (Internet of Things), and other technologies were used to study the use of information technology to enable survey management, develop digital management platforms for marine survey, and optimize management modes. It significantly improved the efficiency of survey operation management and results application, achieved digital results delivery, and was well applied in the Yangtze River estuary region.

Modified model of moisture content distribution of loess profile for loess paleosoil interlayer

He Haichao, Nan Yalin, Yao Miao, Xue Junhao, Wang Zhongyi, Guo Jianhui, Li Jing, Guo Dongxin, Luo Dong

2025, 39(2): 167-176. doi: 10.20265/j.cnki.issn.1007-2993.2024-0575

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To accurately measure the saturation levels of individual soil layers in loess-paleosol interbedded strata and revise the moisture content distribution in loess profiles, the pressure plate method were employed to obtain soil-water characteristic curves for both loess and paleosol in Tongchuan area. Unsaturated seepage numerical simulations were conducted using Midas GTS NX software. Based on simulation data, a moisture content correction model was established and validated against field immersion test measurements. The results of this model were then compared with the measurements from the in-situ immersion test. The study shows that in the same geological age, the influence of different ancient soil on water infiltration is relatively consistent, but in different geological periods, the difference of this influence becomes obvious. The calculated value and measured value of the constructed moisture content correction model are basically consistent with the upward and downward trend in the key nodes such as the junction of loess ancient soil, which can prove the accuracy and scientificity of the moisture content model calculation of multi-layer ancient soil. This study provides a reference for the moisture content correction in the loess areas with the ancient soil layer, which can improve the accuracy of the collapsibility evaluation in the loess-ancient soil reciprocal layer.

Impact of longitudinal cracks on the structural deformation and safety characteristics of tunnel lining

Yang Zhijun, Wang Yonggang, Liu Jingtang, Hu Jinxin

2025, 39(2): 177-184. doi: 10.20265/j.cnki.issn.1007-2993.2024-0099

[Abstract](84) [FullText HTML] (20) [PDF 1425KB](22)

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To investigate the influence of longitudinal crack development on the mechanics and deformation characteristics of the secondary lining structure, a load-structure calculation model was established based on tunnel crack investigation. Stress deformation analysis was conducted for the cracked lining structure. The results indicate that cracking in the lining leads to a decrease in stress (absolute bending moment) in the supporting structure (excluding invert). Moreover, an increase in crack depth causes two changes in bending moment within the structure, resulting in instantaneous local stress loss. However, an increase in lining thickness mitigates this stress loss to some extent. Severe structural deformations occur near cracks at both arch and spinner locations, significantly compromising structural safety. When crack depth accounts for approximately 70% of the lining thickness (around 40% for arch cracks), the safety factor of the lining structure decreases to zero and overall safety linearly declines with an increasing number of cracks. It is evident that when cracking reaches a certain extent, overall safety falls below design specification limits, therefore timely verification and control measures should be implemented for cracks above the arch line to effectively manage their associated deformations. Cracks below this line are prone to crushing damage; hence reinforcement support should be promptly applied to withstand downward pressure from above-the-arch footlining structures. It has theoretical guidance significance for the treatment of lining diseases in operating tunnels.

Construction scheme comparison of tunnel structure simulation comprehensive test platform

Niu Fusheng, Wei Xinyi, Cui Zhen, Lin Chungang

2025, 39(2): 185-191. doi: 10.20265/j.cnki.issn.1007-2993.2024-0188

[Abstract](45) [FullText HTML] (14) [PDF 1587KB](3)

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To build a comprehensive test platform for tunnel structure simulation with more consideration for tunnel disease simulation and treatment, a composite structure of pipe segment and cast-in-place concrete segment was invented. Two specific construction schemes were designed for the pipe segment and cast-in-place concrete segment respectively, and the construction scheme was determined by comparing and selecting according to the calculation of time limit, price, and quantity of machinery required, as well as the site condition and demand priority. The results show that the staggered splicing construction scheme of the pipe segment is tightly bonded and has reasonable structural force. The construction scheme of scaffold + wood formwork in cast-in-place concrete segment has the best price and convenient transportation. The construction scheme of the tunnel structure simulation comprehensive test platform can provide a reference for the construction of other test platforms.

Prediction of road settlement caused by LGWO top pipe tunnel construction

Wang Sai, Zhang Yahui, Wang Yuncheng, Fan Haobo

2025, 39(2): 192-199. doi: 10.20265/j.cnki.issn.1007-2993.2024-0187

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To accurately predict the deformation and settlement caused by a large cross-section pipe tunnel passing through the existing highway, a settlement prediction model based on the adaptive Grey Wolf optimization algorithm was proposed in conjunction with the actual project. Logistic mapping was introduced to generate the initial value, and the convergence factor A in the Grey Wolf algorithm is decomposed into decision factor and attenuation factor to improve the lack of ability of the convergence factor in global and local search. Through the Cangzhou Jiuhe Road Passage human security project for example verification, and with the traditional Grey Wolf algorithm, particle swarm algorithm to compare the prediction accuracy, the analysis results show that the accuracy of Grey Wolf algorithm prediction optimized by Logistic mapping is higher. The accuracy increased by 6.9% compared with the Grey Wolf algorithm without optimization and increased by 2.3% compared with the particle swarm algorithm. The new model has a high degree of practicality and accuracy.

Mechanized matching construction and enclosed rock stability monitoring technology of subsea tunnel

Guo Yongjian, Dai Zhenyang

2025, 39(2): 200-206. doi: 10.20265/j.cnki.issn.1007-2993.2023-0941

[Abstract](43) [FullText HTML] (9) [PDF 1107KB](7)

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To improve the construction efficiency and safety of the ultra-long subsea tunnel, there has been a gradual shift from traditional tunneling methods towards adopting large-scale mechanized integrated construction techniques. To promote the application of mechanized supporting construction methods, relying on the two-way six-lane mainline tunnel of the Jiaozhou Bay second subsea tunnel, a comprehensive analysis of the mechanized supporting construction test section of the ultra-long subsea tunnel was conducted from the aspects of equipment selection, reasonable construction space planning, and tunnel safety evaluation. The full-section construction was adopted in the north tunnel Ⅲ-level surrounding rock, and the bench method was adopted in the Ⅲ-level surrounding rock in the south tunnel and all Ⅳ-level safety surrounding rock. The field monitoring measurement results show that the primary support deformation with the mechanized construction is less than 16 mm, and the surrounding rock and the primary support structure are stable. It is suggested to promote the application on the whole project.

Engineering analysis on the mechanisms of buckling and toppling of bedding rock slope

Xing Qian, Hong Zhaoyuan, Liu Chengzhang, Xie Xinchun, Liu Jian

2025, 39(2): 207-215. doi: 10.20265/j.cnki.issn.1007-2993.2023-0945

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A large number of engineering practices show that the deformation and damage mechanisms of toppling and buckling may exist in the non-sliding damaged bedding slopes. To study the generation mechanism and support scheme of two special mechanisms, the basic conditions, deformation, and failure laws of bedding slopes were studied through discrete element numerical simulation method and relevant data analysis of typical engineering projects, combined with failure tests of layered rock masses. The results show that: for high-rise slopes, when the slope angle is the same or close to the dip angle of the rock layer, the foot of the slope may yield and shallow collapse under the self-weight of the surface layered rock mass, leading to the buckling failuare of the slope; when the slope angle is smaller than the dip angle of the rock layer, the slope may undergo toppling deformation; the toppling deformation and subsequent failure modes of layered slopes need to be viewed separately, and the final failure form is influenced by the evolution of slope deformation and undergoes dynamic changes. For layered rock slopes with mechanisms of buckling and toppling deformation, it is recommended to install high-stiffness support structures at the foot of the slope for support.

Degradation of surrounding rock parameters in deep buried caverns: experimental and numerical simulation study

Yang Chaoshuai, Li Daqiang

2025, 39(2): 216-224. doi: 10.20265/j.cnki.issn.1007-2993.2023-0906

[Abstract](49) [FullText HTML] (12) [PDF 3036KB](15)

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Tunnel excavation can lead to degradation of the stiffness and strength parameters of the surrounding rock, while the degradation law of the surrounding rock parameters during deep buried tunnel excavation is still unclear. Therefore, by conducting cross hole acoustic testing on the surrounding rock of the Muzhailing Tunnel, the spatial distribution pattern of parameter degradation during the excavation process of the tunnel cavern was revealed. At the same time, a parameter degradation model (CSS model) considering the effects of confining pressure and plastic strain was established and applied to the numerical simulation of the project. The results showed that the wave velocity of the surrounding rock decreased during the excavation process, and the degradation pattern of the surrounding rock parameters can be inferred. The use of CSS models can better reflect this parameter degradation phenomenon. The spatial distribution pattern of the deterioration of surrounding rock parameters can be represented by zones. The closer it is to the tunnel wall, the higher the degree of parameter degradation. In areas outside the plastic zone, parameter strengthening may also occur under sufficient confining pressure.

Distribution pattern and cause analysis of loess sinkholes along Pengyang section of Yinchuan-Kunming Expressway

Li Tao, Liu Mingzhao, Yang Yang, Liu Jiayi, Wu Huanjun, Chang Liang

2025, 39(2): 225-231. doi: 10.20265/j.cnki.issn.1007-2993.2024-0018

[Abstract](45) [FullText HTML] (12) [PDF 2757KB](9)

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The Yinchuan-Kunming Expressway section in Pengyang is marked by an exceptional development of loess sinkholes, which significantly compromise the stability of the roadbed and other structural elements. In particular, sinkholes near the roadbed and bridge abutments are susceptible to triggering landslides and collapse, thereby jeopardizing the integrity of the engineering project. A comprehensive analysis of the distribution patterns, causes, and expansion mechanisms of these sinkholes along the expressway was conducted. The findings indicate that sinkholes predominantly occur along the edges of plateaus, on both sides of gullies, at the heads of gullies, and behind landslide or collapse bodies, exhibiting forms such as vertical shafts, funnels, disc shapes, bead-like arrangements, and honeycomb patterns. The loess in Pengyang County, characterized by its loose structure, high porosity, well-developed vertical joints, strong collapsibility, and susceptibility to dissolution and erosion, constitutes the intrinsic factors facilitating sinkhole formation. Additionally, the region’s concentrated precipitation and terrain conditions are conducive to rainwater collection, infiltration, and erosion of slopes, and water plays a role in transportation and dissolution, representing the extrinsic factors. The synergistic effect of these intrinsic and extrinsic factors leads to the exceptional development of loess sinkholes in the Pengyang area.

Optimization design of foundation pit support replacement based on the structural characteristics of rainwater pump station

Huang Xuegang, Zhao Wei, Ma Junying

2025, 39(2): 232-238. doi: 10.20265/j.cnki.issn.1007-2993.2024-0031

[Abstract](58) [FullText HTML] (9) [PDF 2849KB](22)

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The foundation pit of a rainwater pump station is 16.16 meters deep and is supported by retaining piles and 4 steel pipes. The underground second floor of the pump station has a height of 8.9 meters. The original design plan did not include an effective replacement of the third support when it was removed. The removal of the third support will cause the side walls of the underground second floor to be in a cantilever state, seriously affecting the safety of the foundation pit and pump station structure. Based on the structural characteristics of the rainwater pump station, a permanent and temporary support replacement scheme was adopted. A hidden beam and a permanent concrete beam were installed 1 meter below the third support on the side walls of axes ② - ⑤ as replacement supports, which not only solves the problem of replacement supports in the foundation pit but also does not affect the use function of the pump station, avoiding the safety risks of dismantling and replacing supports in limited space. Based on the monitoring data during the excavation stage of the foundation pit, a three-dimensional numerical model of the foundation pit construction process was established using the finite element software Midas GTS. The rationality of the three-dimensional numerical model was verified from the aspects of deep horizontal displacement of support piles, steel support axial force, and column settlement. Then, the validated model was used to simulate the dismantling and support conditions of the foundation pit and predict the deformation of the foundation pit. The analysis results indicate that the optimized design scheme for replacing supports in foundation pits is safe, reliable, reasonable, and feasible, and can serve as a reference for similar engineering projects.

Horizontal bearing characteristics of inclined pile in soft soil foundation

Du Ye, Guo Shengzhong, Liu Yongchao, Wei Chaoqun, Wang Song, Lu Hongyu

2025, 39(2): 239-246. doi: 10.20265/j.cnki.issn.1007-2993.2023-0899

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A field horizontal load test of the inclined pile on a soft soil foundation in Tianjin was carried out, and ABAQUS numerical software was used to analyze the deformation characteristics of the inclined pile. The results show that the horizontal bearing capacity of negative inclined piles is better than that of positive inclined piles. The horizontal bearing capacity of negative inclined piles is proportional to the inclination angle, while that of positive inclined piles is the opposite; Under the action of horizontal load, the main displacement area of the inclined pile body is within the range of 0～12 diameter, and the maximum of the bending moment and axial force of the pile body are located in the range of about 6～8 diameter from the pile top. Compared with positive inclined piles, the bearing performance of negative inclined piles is more significantly affected by the change of inclination angle; The direction of the resultant force of the lateral frictional resistance of the negative inclined pile is opposite to that of the positive inclined pile, and the positive frictional resistance generated is conducive to the bearing performance of the pile body.

Field test on dynamic compaction treatment of large area high-fill red clay foundation

Wang Bangtuan, Yang Long, Liu Wenlian, Xiao Haidong, Sui Sugang, Zhou Yanfei, Xu Pengfei

2025, 39(2): 247-253. doi: 10.20265/j.cnki.issn.1007-2993.2023-0940

[Abstract](63) [FullText HTML] (16) [PDF 1318KB](19)

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Taking the large-scale high-fill engineering of the infrastructure construction project of Yunnan Carbon Neutral Demonstration Industrial Park as the research background, experimental research was conducted on the filling process and dynamic compaction treatment effect of the red clay backfill foundation. The experimental results show that under the energy level of 5000 kN·m, the dynamic compaction method has significant effects on treating the red clay soil-rock layered fill foundation. Among the four filling conditions, condition 2 (using soil-rock layered fill with stone particle size ≤300 mm and soil-rock volume ratio of 5∶5) has the best dynamic compaction reinforcement effect on the foundation, with a characteristic value of foundation bearing capacity of over 240 kPa and a deformation modulus of more than 14 MPa. Based on the test results of this experiment and combined with the experience in Yunnan, specific suggestions for the construction of red clay backfill foundation dynamic compaction treatment in this region are proposed. The experimental research results can provide a reference for the design and construction of similar large-scale high-fill red clay backfill foundations.

Reinforcement effect and construction process of rapid impact compaction for highway reconstruction and expansion

Lyu Bin, Fang Yanhong, Gong Haixia, Liu Yazhen, Chen Jian, Zhang Hongbo, Sun Zhaoyun

2025, 39(2): 254-263. doi: 10.20265/j.cnki.issn.1007-2993.2023-0902

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With the uncertainty in the technology of rapid impact compaction (RIC) for highway reconstruction and expansion, relying on the Ji-Guang Expressway project, the reinforcement effect and construction technology of RIC on loess foundations were studied by adjusting construction parameters such as compaction energy, compaction frequency, and compaction spacing. Meanwhile, the application effect and technical feasibility were verified. The study shows that the RIC can effectively improve the strength depth and compactness of the foundation. The compaction energy and frequency are the main construction parameters that affect the reinforcement effect. The reinforcement effect of the compacted soil shows a linear increase trend with the increase of compaction frequency and compaction energy. The lateral displacement of the soil after compaction shows a parabolic trend with depth, and reaches its peak at a burial depth of 3-4 meters under various compaction spacing conditions. The optimal spacing between compaction points for high-speed hydraulic compaction of loess foundation is 1.5 meters, with a maximum effective reinforcement depth of about 6 meters and a maximum effective reinforcement radius of about 1.6 meters. Based on comprehensive experimental data and theoretical analysis, a calculation formula for the reinforcement range of RIC treatment of loess foundation has been established.

Deformation of surrounding environment caused by vacuum precompression and its prevention

Miao Dan, He Chushao

2025, 39(2): 264-270. doi: 10.20265/j.cnki.issn.1007-2993.2023-0847

[Abstract](53) [FullText HTML] (14) [PDF 1338KB](13)

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Vacuum preloading is a commonly used method for soft soil foundation treatment. To study the influence of vacuum preloading on surrounding soil and corresponding deformation prevention technology, a field test of vacuum preloading reinforced foundation was conducted. Through analysis of monitoring data, the deformation patterns of the surrounding environment were revealed, and the effectiveness of prevention measures was evaluated. Research results show that: (1) vacuum preloading caused a decrease in groundwater levels and pore water pressure in the surrounding area, leading to lateral displacement and settlement; (2) the impact range of vacuum preloading on the surrounding environment was found to be related to soil conditions; (3) in this project, a combination of sand piles and cement-soil mixing piles was adopted as a deformation prevention technology, effectively reducing both horizontal displacement and settlement around the reinforced area by approximately 40%.

Effect of ground fissure activity on groundwater level migration

Zhang Miaozhi, Wang Yahui, Li Qingqing

2025, 39(2): 271-278. doi: 10.20265/j.cnki.issn.1007-2993.2023-0932

[Abstract](54) [FullText HTML] (15) [PDF 4615KB](10)

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To study the influence of ground fissure activity on groundwater migration, hydrogeological pumping tests were conducted at the cross-ground fissure test site on Laodong Road in Xi’an, and a cross-ground fissure hydrogeological test model was established using Geo-Studio software for seepage analysis. The results show that the water inflow of the pumping well on the ground fissure zone is the largest, and the water inflow after the stability of the lower side of the ground fissure is roughly three times that after the stability of the hanging wall. The thickness of the aquifer in the ground fissure zone is the largest and the permeability of the ground fissure zone is the strongest, the footwall is in the middle, and the hanging wall has the smallest thickness and the worst permeability. For the same pumping well, the vertical displacement generated by the combined pumping action and load action is about 4 times that of the single pumping action. For a group of wells, the vertical displacement generated by the combined action of the two is about twice that of the single pumping action. Under the action of water pumping, due to the difference between the hanging wall and footwall of the ground fissure, the increase of effective stress caused by the decrease of pore water pressure will lead to the uneven compression of the soil on both sides and aggravate the development of the ground fissure. When there is no ground fissure, the recharge effect of each pumping well is similar; when there are ground fissures, according to different soil conditions, the ground fissures will show water resistance and permeability.

Comparative model study on test of underground diaphragm wall and cross plate joint under transverse bending

Li Shuaike, Gan Wenju, Zhang Qingyun

2025, 39(2): 279-284. doi: 10.20265/j.cnki.issn.1007-2993.2024-0039

[Abstract](46) [FullText HTML] (11) [PDF 1674KB](2)

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Underground diaphragm walls are common support structures for deep foundation pits. With the widespread application of lattice ground connecting walls in port and wharf engineering in recent years, the research significance of its out-of-plane force has become more prominent. The joint section of the underground diaphragm wall, being its weakest part, has been extensively studied under transverse bending. However, there has been less research on its bending behavior under horizontal loads. Model tests were conducted to compare the bending failure process and shape of the ground wall with the non-joint part and the cross-plate joint. Results reveal that the bending bearing capacity of the diaphragm wall with the cross plate joint is low, and the tensile side is prone to cracking. When approaching the ultimate load, brittle failure occurs at the interface between the steel plate and concrete. The phenomenon shows that the cross plate joint should be regarded as hinge point because of its low bending ability outside the plane, and its application range is limited.

Collapsibility evaluation of thick Malan loess based on field immersion tests

Zhang Sen’an, Wang Xiaolong, Zhang Qinqi, Shi Yilei

2025, 39(2): 285-289. doi: 10.20265/j.cnki.issn.1007-2993.2024-0024

[Abstract](45) [FullText HTML] (11) [PDF 461KB](10)

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According to urban construction in Lanzhou, engineering construction sites are expanding to loess hilly and mound area with thick and collapsible loess. The research results on the collapsible characteristics of loess in Lanzhou are mainly focused on the loess silt with more low terrace engineering construction. Loess(Q₃^eol) in loess hilly and mound area is different from loess silt in low terrace area. To reasonably evaluate the collapsibility characteristics of loess hilly and mound area Malan loess, Malan loess (Q₃^eol) in Lanzhou was taken as the object, based on the field immersion test results and laboratory test results, the collapsibility change characteristics of Malan loess(Q₃^eol) of loess hilly and mound in Lanzhou were discussed. The difference between the field immersion test and the laboratory test were compared, and the β₀ of loess(Q₃^eol) of hilly and mound area in Lanzhou can be modified by 1.0 were put forward, which provides reference for the collapsibility evaluation and foundation treatment design of Malan loess(Q₃^eol) in Lanzhou.

Slump-based soil conditioning of EPB shield in gravelly sand and its prediction study

Li Hui, Tong Fangshuo, Li Bin, Pei Bozheng

2025, 39(2): 290-296. doi: 10.20265/j.cnki.issn.1007-2993.2024-0013

[Abstract](40) [FullText HTML] (10) [PDF 1594KB](5)

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The impact of soil conditioning is a critical factor influencing shield tunneling efficiency in strata of gravelly sand. Through a slump test, the impacts of foam, bentonite slurry, and polymer on the enhanced soil’s flow plasticity were examined. A prediction model of soil slump was provided using machine learning techniques like SVR, KNR, RFR, and BPNN, utilizing the test results as the data sample set. The predicted and real values were then compared and examined. The study indicates that: (1) Foam has a greater impact on enhancing the gravelly sandy soil’s flow flexibility. (2) High-viscosity bentonite slurry or PAM solution should be applied over gravelly sandy stratum with high water content to retain water, improve viscosity, and prevent blowout. (3) The RFR model outperforms the SVR, KNR, and BPNN models regarding prediction accuracy. It can also forecast the slump of the improved waste soil with greater precision. The model’s interpretability was examined as well.

Influence factors of the maximum impact force on the protective structure under rockfall

Chang Li’an, Ai Yan, Liu Hongyan

2025, 39(2): 297-304. doi: 10.20265/j.cnki.issn.1007-2993.2024-0058

[Abstract](51) [FullText HTML] (8) [PDF 2112KB](18)

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The maximum impact force caused by the rockfall on protective structures is the premise and basis for the design of protective structures, so it is of great engineering significance to accurately predict it. Therefore, to explore the influence factors of the maximum impact force caused by the rockfall on the protective structure under different rockfall parameters and protective structure characteristics, a set of rockfall impact test device was designed. The maximum impact of the rockfall of three different shapes, such as spherical, cylindrical and irregular, on the protective structure under different the following conditions, such as rockfall mass, rockfall height, slope gradient, protective structure angle and buffer layer thickness, was studied. The test results show that the maximum impact force of the rockfall on the protective structure increases linearly with the increase of the mass and height of the rockfall, increases rapidly with the increase of the slope gradient and the angle of the protective structure, and decreases linearly with the increase of the buffer thickness. In addition, it is found that the maximum impact of the shape and height of the rockfall on the protective structure will cause greater dispersion, and the maximum impact of the irregular shape of the rockfall on the protective structure is mainly due to the complexity of the rockfall motion process and the uncertainty of the impact blocking process caused by the irregular shape of the rockfall. It is concluded that the impact attitude of the rockfall and its contact mode with the protective structure have a very important influence on the maximum impact force of the protective structure. The research results can provide reference for the prevention and control of rockfall disasters and the design of protective structures.

Comparative experimental study on grouting of fine cement and ordinary cement in underground engineering

Jing Shaodong, Ding Changdong, Jia Chunlei, Zhang Yihu, Zhu Yujie

2025, 39(2): 305-310. doi: 10.20265/j.cnki.issn.1007-2993.2024-0174

[Abstract](59) [FullText HTML] (12) [PDF 909KB](16)

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Underground projects such as water-sealed caverns, gas storages, and diversion tunnels have strict requirements for the control of regional seepage fields. Grouting is an important way to control the seepage field in the engineering area. The groutability under different geological conditions is different, and the sensitivity to the particle size of grouting material is different. It is necessary to carry out relevant experimental demonstrations to provide a scientific basis for engineering construction. Based on the grouting construction of a water-sealed cavern, and by conducting comparative experiments of ultra-fine cement, wet grinding fine cement, and ordinary cement grouting, the applicability of different types of grouting materials was studied in the project. The test results show that when the rock permeability is high, there is no obvious difference in the seepage control effect of the three grouting materials. Under the condition of the same permeability of rock mass, different materials were used for grouting, and the unit ash consumption was generally the same. With the increase in grouting pressure, the unit ash consumption of the grouting hole increased significantly, and the effect of grouting was significantly improved. When the rock permeability is very low, using ultra-fine cement or wet-grinding fine cement can further reduce the seepage of the surrounding rock. Therefore, there is no need to use ultra-fine cement and wet grinding fine cement for grouting on a large scale in this project. In special cases where the groutability of ordinary cement is not good, it is recommended to use ultra-fine cement and wet-ground fine cement and to reasonably adjust the grouting pressure to significantly improve the grouting effect.

Monitoring andanalysis of water and soil pressure on diaphragm wall during excavation of deep foundation pit

Zhai Tianqi

2025, 39(2): 311-316. doi: 10.20265/j.cnki.issn.1007-2993.2024-0443

[Abstract](102) [FullText HTML] (18) [PDF 796KB](25)

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Aiming at the safety problem of deep foundation pit engineering in the development of urban underground space, the change of water and soil stress caused by the construction of underground continuous walls is taken as the research object. Through theoretical analysis and field monitoring data comparison, the calculation method and actual deformation law of soil pressure of foundation pit retaining structure are discussed. It is found that the monitoring value of water and soil pressure of the diaphragm wall can effectively reflect the actual stress state of the foundation pit retaining structure. In this deep foundation pit project, the use of shovel-shaped stratum stress monitoring devices enables the observation of soil and water pressure variations both within and outside the pit during the excavation process. This data is then evaluated against the values calculated during the design phase for comparison. The results show that the designed earth pressure of the foundation pit under the static state is consistent with the measured value, and the monitoring value of the earth pressure during the excavation process is smaller than the theoretical calculation value, which is related to the wall displacement and groundwater seepage. This study has certain guiding significance for studying the deformation law of foundation pit based on field monitoring data, to optimize the design scheme.

Current Issue 2025, Volume 39, Issue 2

Current Issue
2025, Volume 39, Issue 2