岩土工程技术

2023, 37(4)

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2023, 37(4): 1-3.

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Review of Design and Application of Geotechnical Centrifuge

Wen Jiwei, Chen Haotian, Zeng Xianen, Xiang Tian

2023, 37(4): 379-385. doi: 10.3969/j.issn.1007-2993.2023.04.001

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In the civil engineering, geological engineering and other related fields, in order to analyze the prototype conditions of rock and soil mass or structure in the laboratory, the geotechnical centrifuge is often used to carry out scale simulation experimental research. A variety of science and technology has developed rapidly in recent years, including hydraulic transmission, electrical control, micro-sensors and observation technology, etc., and the geotechnical centrifuge model test has transitioned from the initial qualitative analysis to quantitative analysis. It can provide an effective technical approach to solve many complex engineering problems such as landslide disaster, underground structure excavation and stability, foundation failure, site liquefaction, pile foundation destruction and so on, and a lot of research achievements have been obtained. Taking the arm type geotechnical centrifuge as the main object of discussion and research, through the principle, development situation, structure composition and existing main problems of the geotechnical centrifuge, the improvement scheme of the centrifuge design was put forward. Combined with the development process and application field of the current geotechnical centrifuge, the future research and application direction of this technology is prospected, which can provide a certain reference for the research and application.

A Reservoir Protection Engineering Case of Navigation and Power Junction Project

Hou Junwei, Zuo Libing, Xu Wenteng

2023, 37(4): 386-391. doi: 10.3969/j.issn.1007-2993.2023.04.002

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The right side of the hub project reservoir area is adjacent to an abandoned coal mine. There are abandoned goafs and coal tunnels within the inundation line of the storage area. After impoundment of navigation power junction, the reservoir water may leak into the goafs through exposed coal tunnels and bank slope rock fractures, affecting the normal water storage in the area. Through various engineering survey methods such as surveying and mapping, geological drilling, and geophysical exploration (high-density electrical method), the distribution positions of coal seams, goafs, and coal tunnels were identified. A protection plan combining grouting and sealing of abandoned coal tunnels, anti-seepage curtains, and anti-seepage retaining walls was developed and implemented. The effectiveness of anti-seepage engineering has been verified through experiments, ensuring the safety of normal water storage in the reservoir area, which has certain reference significance for similar projects.

Combined Prediction of Foundation Pit Deformation under the Condition of Data Filtering

Han Guofeng

2023, 37(4): 392-396. doi: 10.3969/j.issn.1007-2993.2023.04.003

[Abstract](87) [FullText HTML] (41) [PDF 606KB](20)

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In order to evaluate the deformation law of foundation pit construction process reasonably, based on the deformation monitoring results, the filtering of deformation data was realized by double tree complex wavelet, and then the sub-combination prediction was realized by GWO RVM model, ARIMA model and chaos theory. The analysis of the example shows that the deformation data of foundation pit can be effectively decomposed into trend and error components by double tree complex wavelet. The decomposition effect can be further improved by optimizing the model parameters, which is more powerful than traditional wavelet. At the same time, the applicability of various sub item prediction models in different deformation components is also strong. The average relative error of the combined prediction results is about 2%, which is obviously better than the traditional prediction model. It verifies the applicability of the combined prediction method in the deformation prediction of foundation pit, and provides a new way for the research of deformation development law of foundation pit.

Calculation Method of Unsaturated Loess Matrix Suction by In-situ Soaking Test

Peng Min, Guo Jianhui, Guo Dongxin, Ma Jianxun, Luo Dong

2023, 37(4): 397-402. doi: 10.3969/j.issn.1007-2993.2023.04.004

[Abstract](85) [FullText HTML] (17) [PDF 1291KB](18)

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When the permeability coefficient of unsaturated soil is calculated by a relatively accurate algorithm considering the suction head value of the soil matrix in the project, it is difficult to accurately measure the suction head value of the matrix, and the measurement results of the laboratory test are quite different from the head value measured in the field. A new algorithm was used to calculate the soil matrix suction by using the in-situ water immersion test data. It is different from various traditional testing methods such as the indoor tensiometer method. Instead, it uses the Green-Ampt infiltration model combined with the immersion pit. The suction head value of the formation matrix is calculated from the difference between the water surface falling rate and the water infiltration rate measured by the moisture sensor. Select a loess paleosol interlayer site for in-situ immersion testing. The suction head value of the first layer of loess matrix with a thickness of 4 meters is 233 cm, and the value of the second layer of paleosol with a thickness of 2 meters is 124 cm. Using this algorithm, the suction head value of each layer of soil matrix can be predicted and calculated, and finally it is predicted that the suction of the stratum matrix will decrease to zero at 8.4 m below the immersion pit. This is a new attempt to calculate the suction of soil matrix in loess strata.

Method and Application of Determining Ultimate Bearing Capacity of Existing Piles Based on Catastrophe Theory and Specific Energy Comparison Method

Liu Jianfei, Gao Chao, Zhou Yongming

2023, 37(4): 403-407. doi: 10.3969/j.issn.1007-2993.2023.04.005

[Abstract](96) [FullText HTML] (18) [PDF 1060KB](11)

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In order to further excavate the vertical bearing capacity of existing pile, the load displacement curve equation of the test pile was derived by using the principle of the least square method according to the load displacement curve of the test pile and the bearing behavior of the foundation pile, and the extension of the load displacement curve was fitted. On this basis, in order to predict the vertical ultimate bearing capacity of the pile, the catastrophe point method and the specific energy comparison method were used. The specific energy of the pile-soil system was used as a catastrophe criterion. The load-displacement curve equation of the test pile was used to obtain the cusp catastrophe specific energy curve and the catastrophe point specific energy, and the average shear strength of the pile side soil layer was compared to determine the critical failure state of the pile and soil. The research shows that the curve of pile top deformation-graded loading value is formed through the specific energy function equation of pile foundation, and the catastrophe theory is used to deduce the vertical ultimate bearing capacity of pile. The physical meaning is clear, which can provide a theoretical basis for the prediction of the actual vertical ultimate bearing capacity of existing pile foundation and the determination of the maximum loading value of engineering test pile.

Application of Mindlin Solution in Calculation of Ground Settlement in Composite Stratum Shield Tunnel Construction

Chen Junsheng, Xu Chengkai, Gao Qiang

2023, 37(4): 408-414. doi: 10.3969/j.issn.1007-2993.2023.04.006

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In the coastal areas of South China, Southeast China and North China, it is common that the upper part of the tunnel body is a soft soil layer, and the lower part is a hard rock stratum with high strength. The problem of land subsidence caused by shield tunneling has not been studied at present. To address this situation, the idea of using Mindlin solution to solve for surface subsidence was continued. In order to overcome the limitations of extended Mindlin solution for non-uniform strata, the layer state vector was introduced, and the integral transformation and matrix derivation were used to solve the relationship between displacement and stress at different layers. An extended Mindlin solution for composite formations was established. Finally, the adaptability of the Mindlin solution and the extended Mindlin solution to the surface subsidence of shield tunnels in composite strata were compared and compared with the actual engineering monitoring data. The derivation process shows that using the Mindlin solution or the extended Mindlin solution to solve the surface subsidence faces difficulties and needs to be simplified to a certain extent, while the engineering monitoring data show that the calculation results of the Mindlin solution are large, which can be used as a reference for engineering design. The method of extended Mindlin solution for calculating surface subsidence has certain accuracy.

Damage Characteristics of Prefabricated Fractured Granite after High Temperature

Wang Fuchun, Huang Shouguo, Huang Cong

2023, 37(4): 415-421. doi: 10.3969/j.issn.1007-2993.2023.04.007

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Temperature is one of the important factors affecting the physical and mechanical properties of rock. The study of the influence of high temperature on the evolution of rock mechanical properties and damage mechanism is of great significance in the construction of deep rock mass engineering. Based on the PFC particle flow numerical simulation method, the uniaxial compression experiments of pre-existing flaws granite treated at different temperatures (20 ℃,200 ℃,400 ℃,600 ℃,800 ℃) were simulated. The results show that the peak strength and elastic modulus of granite decrease significantly with the increase of heat treatment temperature, while the peak strain increases. The degree of thermal damage caused by different heat treatment temperatures varies, leading to differences in macroscopic failure modes of prefabricated fractured granite. When the heat treatment temperature does not exceed 600 ℃, the granite undergoes failure along both ends of the prefabricated crack; When the heat treatment temperature reaches 800 ℃, thermal damage becomes the dominant factor in the mechanical failure mode of granite, and the degree of fragmentation significantly increases. The research results contribute to understanding the mechanism of rock damage evolution under high temperature, and can provide reference for deep underground engineering.

Highway Tunnel Vertical Filling Type Cave Roof Caving and the Treatment of Catastrophic Impact Factor Analysis

Liu Dingqing, Xie Wo, Jia Yanling

2023, 37(4): 422-427. doi: 10.3969/j.issn.1007-2993.2023.04.008

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Based on a highway tunnel in the area in guangxi karst cave roof collapse case, according to the treatment design of karst disaster, the finite element software was used to simulate the treatment effect, and the deformation law of the vertical developed filling cave with tunnel crossing was obtained. On this basis, in order to prove the effectiveness and rationality of the disaster treatment scheme design, the three major disaster control factors of pipe shed support, initial support thickness and geological characteristics were studied by using the control variable method, and the influence of each factor on the stability of the tunnel structure was analyzed. The engineering treatment effect, model calculation result and monitoring measurement result prove that the design of disaster treatment scheme is reasonable, safe and reliable. The relevant research results have certain reference significance for the design and construction of similar karst tunnel engineering.

Discussion on Identification of Hidden Ground Fissures in Type Ⅲ Typical Loess Terrace Sites

Wang Xin, Li Xiaogang, Ding Xiaoqiang, Wang Yahui

2023, 37(4): 428-432. doi: 10.3969/j.issn.1007-2993.2023.04.009

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Xi'an ground fissures are developed due to excessive exploitation of groundwater and uneven settlement. Among them, the type Ⅲ site belong to the development area of hidden ground fissures. The existence of hidden ground fissures in type Ⅲ site in typical loess stratum was investigated and identified by means of geological survey, engineering geological drilling and other means, and the location and trend of ground fissures were determined. The results show that the ground fissure in this section matches the F₃ ground fissure that has been proved in Xi'an area. It is suggested that the avoidance distance should be reasonably selected to prevent economic losses. Through the investigation of the ground fissures and the study of the engineering geological characteristics, it can provide a reference for the investigation and exploration of the ground fissures in type Ⅲ typical loess sites in Xi'an area in the future.

Estimating the Bearing Capacity of Bored Pile Based on the Data of Static Cone Penetration

Liu Dan, Zhou Yufeng

2023, 37(4): 433-437. doi: 10.3969/j.issn.1007-2993.2023.04.010

[Abstract](144) [FullText HTML] (22) [PDF 898KB](38)

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According to the current specifications such as "Technical Specification for Building Pile Foundations" (JGJ 94—2008) and "Specifications of Foundation of Highway Bridges and Culverts" (JTG 3363—2019), the standard values of vertical ultimate bearing capacity of single pile calculated by static cone penetration test are all for precast pile, and there is still no formula for bored cast-in-place pile. In this study, based on the actual situation in Beijing and the relationship between the empirical values of the concrete precast pile and the bored pile with slurry wall protection in the current code, an empirical formula is established to estimate the standard value of the vertical ultimate bearing capacity of the bored pile by the static penetration method. Combined with engineering examples, it shows that the value of estimating the bearing capacity of bored pile by static cone penetration test is much higher than the traditional look-up table method in deep sand layer.

Experimental Study on Compressive and Tensile Failure Characteristics of Different Rocks

Luo Guitao

2023, 37(4): 438-442. doi: 10.3969/j.issn.1007-2993.2023.04.011

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The acoustic emission (AE) monitoring system is used to monitor the Brazilian splitting and uniaxial compression of the marble, granite, limestone, and sandstone in order to investigate the evolution pattern of different rocks during fracture. The results show that the stress changes are non-linear and linear and different rocks produce secondary damage in Brazilian splitting tests. The uniaxial compression conditions present typical full stress-strain curve characteristics when damage occurs in different rock samples, and the changes in AE parameters are more consistent with stress changes, but there are differences in the response of different lithologies to AE parameters. The AE counts and AE hits are more sensitive to the rock damage, and the harder the rock is, the more energy is released.

Response Difference of Aeolian Sand and Gravel Soil Low Embankment under Vehicle Loading

Liu Dapeng, Wang Jing, Cheng Qiangqiang, Liu Mengxi

2023, 37(4): 443-448. doi: 10.3969/j.issn.1007-2993.2023.04.012

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Aeolian sand and gravel soil are commonly used as subgrade fillers in oasis-desert area of Xinjiang. In order to find out the difference of stress and strain response of low embankment of aeolian sand and gravel soil under vehicle loading, 1:1 full scale models of low embankment were established by using aeolian sand and gravel soil as subgrade fillers, and the model tests of low embankment under static load, short-term dynamic load and long-term dynamic load were carried out with the foundation moisture content of 18%, 23% and 28% respectively. The test results show that the stress and strain of low embankment are the largest under long-term dynamic load, and the minimum under short-term dynamic load. Under static load, short-term dynamic load and long-term dynamic load, the stress of gravel soil and aeolian sand low embankment decreases with the increase of depth, and the attenuation speed of gravel soil low embankment is faster. There is a dividing point in the stress response at 0.6~1.0 m from the top of the subgrade. The stress of the gravel soil low embankment from the top of the subgrade to the dividing point is greater than that of the aeolian sand low embankment, and the stress of the aeolian sand low embankment below the dividing point is greater than that of the gravel soil low embankment. The strain of each structural layer of gravel soil low embankment is smaller than that of aeolian sand low embankment. With the increase of foundation moisture content, the strain of aeolian sand low embankment foundation increases greatly.

Experimental Study on the Stick-slip Phenomenon in Granular Materials and Its Physical Mechanism

Liu Jiansheng, Xiong Wenyong, Deng Xianghao, Fu Li, Tong Lihong

2023, 37(4): 449-454. doi: 10.3969/j.issn.1007-2993.2023.04.013

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In order to explore the internal relationship between the macro mechanical response of granular materials in the shear process and their micro parameters, the stick-slip behavior of granular materials under compression and shear was studied through indoor direct shear test. Glass beads were used as granular materials to conduct direct shear test under different normal stresses, and the rate state friction model (RSF) was introduced to quantitatively analyze the test results, and the relevant parameters of the rate state friction model were obtained through the strength step test. The experimental results show that: (1) the variation trend of the stick-slip curve under different normal stresses is basically the same and shows a periodic pattern, but the stress drop and period caused by stick-slip decrease with the decrease of normal stress; (2) within the applied pressure range, the stiffness ratio κ is calculated to be less than 1, and κ decreases with the increase of normal stress. This indicates that the granular material meets the instability criterion, and the experimental phenomenon is consistent with theoretical predictions. This provides ideas for studying the mechanism of earthquake occurrence, and based on this, it can be inferred that the stick-slip instability of faults and the cause of earthquakes are caused by the instantaneous change of slip velocity at the fault plane. The smaller the κ value, the greater the peak stick-slip rate, and the greater the stress drop and stick-slip period generated.

Study on Environmental Durability of Solidified Lake-bottom Sediment

Wang Kuangshan, Pang Long, Dai Zhenxin, Zhang Hui, Zhang Xinjun

2023, 37(4): 455-460. doi: 10.3969/j.issn.1007-2993.2023.04.014

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In order to evaluate the environmental durability of solidified lake-bottom sediment, alkali activated cementing material of slag system (slag powder, metakaolin, lime and sodium silicate) and traditional cement were used as curing agent. Through unconfined compression, freezing-thawing cycle, Na₂SO₄ and NaCl erosion leaching, scanning electron microscopy and EDS-Mappingtests, the typical hydrates, strength evolution, mass loss rate and microstructure characteristics of solidified sediment in erosion environment were analyzed. The results show that a large amount of hydrated sodium silicate aluminate gel（N-A-S-H）was formed in the alkali-excited solidified sediment. The freezing-thawing cycle and erosion leaching can lead to the deterioration of the strength of solidified sediment. The development of ettringite led to expansion and cracking when the cement-solidified sediment was eroded by sulfate, which resulted in the decrease of strength. The alkali-activated curing agent has better chloride ion resistance than sulfate ion and better comprehensive environmental durability than conventional Portland cement.

Experimental Study on Dry Shrinkage Cracks of Expansive Soil Modified by Polypropylene Fiber

Huang Furong, Fang Yarong, Tan Mengjuan, Wang Zhuo, Li Jia, Wang Liang, Guo Hong

2023, 37(4): 461-464. doi: 10.3969/j.issn.1007-2993.2023.04.015

[Abstract](64) [FullText HTML] (36) [PDF 724KB](20)

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To explore the inhibition effect of polypropylene fiber on shrinkage cracks of expansive soil, the development, evolution and characteristics of surface cracks of expansive soil samples with and without fibers were qualitatively described and quantitatively analyzed at the same evaporation temperature. The results show that the polypropylene fiber has a significant inhibition effect on the cracks of expansive soil during the process of water evaporation, and the ratio γ of the number of cracks to the joint of cracks can reflect the penetration degree of cracks. The smaller the value, the stronger the penetration degree of cracks. This physical improvement method can make the polypropylene fiber connect with expansive soil as a whole, and then spread the dry shrinkage stress into expansive soil, effectively slowing down the speed of crack development, so the results can be generalized and applied in the treatment of roadbed in the area of dry shrinkage crack expansive soil.

Research of In-situ Borehole Shear Test of Loess

Huang Xiaowei, Liu Zijun, Yang Zhenrong, Zheng Jianguo

2023, 37(4): 465-469. doi: 10.3969/j.issn.1007-2993.2023.04.016

[Abstract](88) [FullText HTML] (16) [PDF 942KB](16)

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It is very important to accurately obtain the in-situ shear strength parameters of loess for loess engineering. In this study, borehole shear test (BST) was applied to test the shear strength parameters of loess on a loess landslide in Xi'an. The suitable drilling method in loess site was proposed, and a micro displacement-shear strength measurement system was added on the basis of the original Iowa borehole shear test to accurately measure the normal displacement and shear stress. The results of BST and direct shear test were compared. The results show that the improved equipment is more visible and controllable; the normal stress is proportional to displacement, which indicates that the soil is in the stage of quasi elastic deformation. To ensure the reliability of the results, the time for consolidation under the first stage of normal stress needs 10 min while 5 min meet the requirement in the subsequent stages. Compared with the direct shear test, the internal friction angle measured is larger for 40.8% on average while cohesion is 12.7% smaller. The borehole shear test shows a good performance on the test of the shear strength parameters of loess in-situ.

Direct Shear Behavior of Three-dimensional Geogrids-soil Interface with Different Square Apertures under Various Shear Rates

Xiong Bo, Tong Yanguang, He Jianghui

2023, 37(4): 470-474. doi: 10.3969/j.issn.1007-2993.2023.04.017

[Abstract](73) [FullText HTML] (21) [PDF 1198KB](12)

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For reaching the influence of the aperture of the three-dimensional geogrids with enhanced transverse ribs on the interface behavior, three geogrids with different square apertures were made by 3D printing technology. Effect of the square apertures (25 mm×25 mm, 35 mm×35 mm, 45 mm×45 mm), vertical stresses (20, 40, 60 kPa), shear rates (0.5, 1, 2 mm/min) were investigated by large scale direct shear test. The results show that the peak shear stress and friction angle of the interface between the geogrid with aperture of size 35 mm×35 mm and soil are greater than others; as the shear rate increases doubly, the peak shear stress changes less, and the rate of peak shear stress change at different shear rates is between −4% and 11%; the greater the vertical stress, the greater the peak shear stress, and the rate of peak shear stress change is greater than 20%, indicating that the vertical stress has obvious effect on the shear character of the interface of reinforced soil.

Design and Evaluation of Internal Support and Anchor Support in Complex Environment for Deep Foundation Pit

Ji Xiaopeng, Ji Fanji

2023, 37(4): 475-480. doi: 10.3969/j.issn.1007-2993.2023.04.018

[Abstract](119) [FullText HTML] (33) [PDF 1848KB](44)

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By taking an ultra-deep foundation pit project in the central area of Beijing as an example, according to the different surrounding environment of the foundation pit, the supporting systems of diaphragm wall+ reinforced concrete internal support and diaphragm wall + upper prestressed anchor and lower reinforced concrete internal support were respectively adopted in this project. It effectively controls the deformation of the foundation pit itself and surrounding buildings, and ensures the safety and stability of the foundation pit supporting system and surrounding buildings. At the same time, if the surrounding space conditions match, the upper prestressed anchor could be used to replace partial internal support. It can save the construction period and reduce the cost, and has reference value for similar projects.

Influence of Open Dewatering on the Deformation of Deep Foundation Pit in Saturated Soft Loess Area

Zhang Xiaohui, Wang Yonghua, Yang Lina, Bu Chongpeng, Wang Mingjiao

2023, 37(4): 481-485. doi: 10.3969/j.issn.1007-2993.2023.04.019

[Abstract](101) [FullText HTML] (27) [PDF 1476KB](21)

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Saturated soft loess is a special stratum different from collapsible loess and saturated compacted loess. In order to analyze the influence of open dewatering on the deformation of deep foundation pits in strata rich in saturated soft loess, a typical deep foundation pit in Xi'an was selected for analysis. The changes of soil physical and mechanical properties before and after dewatering were analyzed in detail, the bond strength of saturated soft loess strata before and after dewatering was discussed, and the measured and calculated values of deformation of deep foundation pits before and after dewatering were compared. The research results provide a reference for the selection of design parameters for deep foundation pits in layers rich in saturated soft loess in terms of changes in physical and mechanical properties, bond strength improvement and deformation control, and provide regional experience for similar projects.

Application of Solid Concealed Bracing in Deep and Large Foundation Pit Engineering in Soft Soil

Quan Wei, Zhu Pudong

2023, 37(4): 486-491. doi: 10.3969/j.issn.1007-2993.2023.04.020

[Abstract](89) [FullText HTML] (43) [PDF 4077KB](26)

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Taking a project near Yangtze River and railway in Wuhan as an example, the mixing pile reinforcement was used as concealed bracing for supporting in foundation pit engineering under the conditions of deep and weak stratum, limited surrounding environment and strict deformation control. This supporting measure can effectively improve the deformation resistance of the support structure, reduce the pile diameter and reinforcement ratio of the support pile, facilitate the outward transportation of earthwork and protect the engineering pile. The finite element simulation calculation and measured data show that the horizontal displacement of the pillar pile is obviously restricted by the concealed bracing at the bottom of the pit, and the pile deformation and ground settlement meet the corresponding requirements. This research could provide reference for the application of similar foundation pit projects.

Impact Analysis of Foundation Pit Excavation Near the Existing Metro Station Auxiliary Structure

Zhang Xu, Wang Jiejie

2023, 37(4): 492-498. doi: 10.3969/j.issn.1007-2993.2023.04.021

[Abstract](124) [FullText HTML] (23) [PDF 4985KB](46)

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The foundation pit excavation near the existing metro station auxiliary structure is expected to have impact on the metro station auxiliary structure and the safe operation. Taking the construction of the deep foundation pit of a Sunken Plaza in Shijiazhuang as the background, by dividing different construction stages, MIDAS software was used to simulate and analyze the impact of the construction on the horizontal and vertical displacements attached to the neighboring stations, and the results were compared with the monitoring results. The calculated displacement is superimposed on the interval tunnel to check its reinforcement and cracks. The results show that: with the construction of the sunken square, the metro station auxiliary structure will produce horizontal and vertical displacement. The displacement of the metro station auxiliary structure reaches the maximum when the excavation reaches the bottom of the foundation pit, and the vertical displacement is mainly. After checking the displacement superposition of the metro station auxiliary structure, the reinforcement and cracks of the interval tunnel meet the requirements of the specification. By comparing the calculated results with the measured results, the deformation law of the calculated results and the measured results under various construction conditions is generally consistent, which proves that the numerical simulation results are reasonable and feasible.

Design and Monitoring Analysis of a Deep Foundation Pit in Beijing

Jin Xu, Miao Xiaopeng, Lv Shenglan, Liu Tianyang, Shao Lei

2023, 37(4): 499-504. doi: 10.3969/j.issn.1007-2993.2023.04.022

[Abstract](221) [FullText HTML] (26) [PDF 2002KB](53)

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Based on the geotechnical investigation and monitoring data of Jishuitan Hospital project of deep foundation pit supporting, a three-dimensional excavation model by MIDAS GTS was used to simulate the deformation of adjacent buildings caused by deep excavation during construction. To verify the reliability of MIDAS GTS software applied in engineering, earth pressure, horizontal displacement of support structures, and settlement of surrounding buildings were monitored. The reliability of the numerical simulation analysis and calculation results was verified by comparing the data obtained from the 3D model simulation with actual monitoring data. The research results indicate that numerical simulation analysis can serve as an auxiliary means for the design and scheme comparison of foundation pit support, and can provide reference for the layout of foundation pit monitoring points.

2023 Vol. 37, No. 4