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28 February 2025, Volume 39 Issue 1 Previous Issue    Next Issue

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Impact of a New Shielded Tunnel Underpasses the Existing Operating Tunnel GU Kai, ZHANG Xiangxiang, CHEN Bigang 2025, 39 (1):  1-04.  Abstract ( 292 )   Save To obtain the influence pattern of a new shield tunnel underpass the existing operating tunnel, the construction case history of the Xiamen Metro Line No. 4 underpasses an existing operating highway tunnel is presented in this paper. The commercial software Midas GTS NX to simulate the whole process of the shield tunnel under passing the existing operating tunnel in the left and right lines respectively, and to investigate the influence of the under passing tunnel angle and other factors on the mechanical behavior of the operating tunnel, the research results show that: as the shield tunnel continues to excavate, the results show that the existing tunnel settlement increases as the shield tunnel is excavated, but the existing tunnel settlement only changes significantly when the shield tunnel is excavated directly below the operating tunnel; the final settlement of the existing tunnel increases as the angle of the underpass tunnel decreases. The results of the study can provide a scientific reference for similar projects. Related Articles | Metrics

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Engineering Application of an In-Situ Solidification Method HUANG He 2025, 39 (1):  5-07.  Abstract ( 254 )   Save With the construction of new rural areas, the concept of “Highway Beautification” is being fully integrated into the construction process, and the principles of “no damage is the greatest protection” and “resource conservation, lowcarbon cycle” are creatively followed to optimize the better utilization of land resources. The selected project is to be built into a harmonious and unified with “highway, nature, and humanity”, with green, environmental protection, and local characteristics. The implementation of the in-situ solidification technology has improved the efficiency of the soft soil improvement and reduced the pollution caused by the waste soil and contaminated soil to other land resources and rivers. The soft soil is solidified on site, reducing the utilization of sands and gravels, and allowing zero discharge of the engineering soil waste, reducing the environmental impact of waste earthwork transportation and piling, improving the water and soil environment of the construction site, saving land resources, and reducing treatment costs. The in-situ solidification technology can provide effective support for soft foundation treatment. Related Articles | Metrics

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Emergency Mitigation and of High-Pressure Artesian Water Inrush a Large Deep Excavation Project in Yangtze Floodplains at Jiangbei New District of Nanjing FANG Qing, MA Shiqiang 2025, 39 (1):  8-12.  Abstract ( 278 )   Save As the Nanjing Jiangbei New District is designated as a state-level new district, the development and construction of Yongjiang new Jiangbei main city has become one of the major projects in Nanjing’s urban development. The Linjiang stratum is a typical Yangtze River floodplain dual structure stratum, with the upper part of 20 m~30 m soft silty soil and the lower part of deeply deposited saturated fine sand, medium coarse sand and gravel sand with artesian high groundwater head, which has a great influence on the deep excavation projects. The high-pressure artesian groundwater is easily inducing the water intrusion hazard in deep excavation projects, which results in great economic losses to owners and the society. Based on a successful case history of mitigating a deep and large excavation intrusion in Jiangbei New District, different emergency treatment methods are adopted according to the different volumes of the intrusions in the excavated area. The mitigation results are summarized to provide technical reference for the similar engineering projects, especially in the Yangtze River floodplain areas. Related Articles | Metrics

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Safety Impact of New Roadway and River Excavation Construction on a Rail Transit Tunnel TIAN Shuai, WEI Bang 2025, 39 (1):  13-16.  Abstract ( 180 )   Save Based on the construction of the new roadway and river excavation across the shielded tunnel section from Qingshuwan Station to Huagang Station of Suzhou Rail Transit Line No. 4, and based on the relative positional relationship among the roadway, the river and the shielded tunnel section, as well as the structural characteristics of the shield tunnel section, a three-dimensional numerical analysis model is established to simulate and analyze the impact of the new roadway and river excavation on the stress and deformation of the existing shielded tunnel section structure. The results show that the river excavation and the unloading can cause uplift and deformation of the shielded tunnel section below. It is necessary to reasonably arrange the excavation sequence of the river above the rail transit project to minimize the unloading exposure time; Roadway construction and subsequent roadway traffic operations may cause settlement and deformation of the shielded tunnel section below. The construction surcharge load and the heavy machinery should be kept away from the track control protection zone. The research results provide a reference for the construction design of adjacent rail transit roads and river courses. Related Articles | Metrics

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Mechanical Characteristics of a H-Type Double-Row Pile Retaining Structure in Chengdu MENG Baohua, MA Jingjing, ZHANG Ning, DENG Yu 2025, 39 (1):  17-23.  Abstract ( 170 )   Save Combined with the monitoring data of the deep excavation and surrounding buildings during the construction, the numerical simulation of the H-type double row pile + ground anchor support was performed by using the FLAC3D to verify the validation of the model. Furthermore, the optimization is carried out from the aspects of double row pile row spacing, pile top height difference and pile bottom height difference, and reasonable advice are proposed to provide a reference for the design and construction of the composite support structure. Related Articles | Metrics

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Stability Analysis and Reinforcement Effect of a Slope in Qinglong Mountain GAO Rui, ZHANG Zhenbi, LI Lichen, GUAN Peng 2025, 39 (1):  24-28.  Abstract ( 167 )   Save A slope of Qinglong Mountain in Wuhan City is presented in this paper as case history of the slope stability analysis. The factor of safety of the slope is analyzed. The deformation, the damage mechanism, and the damage mode of the slope are evaluated. The slope management plan of “slope shaping + lattice beamed ground anchors + drainage measures + slope vegetation + monitoring” was utilized based on the analytical results. The actual conditions of the slope, the management plan and the slope remediation plan are introduced in detail in this paper. The factor of safety against the mitigation slope stability is estimated. The results showed that the treated slope is in a stable state under heavy rainfall conditions. The slope monitoring results show that the vertical accumulated settlement and settlement rate of the slope are within the tolerable range. After the treatment, the stability of the slope has been greatly improved. This study can provide a reference for the reinforcement design of similar slopes. Related Articles | Metrics

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Impact of a Large Deep and Large Excavation on the Adjacent Subway Shielded Tunnel Section ZHANG Hongzhang, FAN Weiqin, XIE Zhaoyu, XIONG Zonghai, XIE Wujun 2025, 39 (1):  29-34.  Abstract ( 172 )   Save A deep excavation is adjacent to the planned subway section and is supported by soldier piles and double row cement mixing columns outside the soldier piles. By using MIDAS/GTS NX, the numerical analysis was conducted to study the impact of the deep excavation on subway sections and the impact of the subway section construction on existing building structures. The analytical results indicated that, when the proposed project is started after the completion of the subway section construction, the maximum horizontal displacement of the subway section structure towards the deep excavation direction is 8.8mm and the maximum settlement is 6.6mm; When the proposed project is completed before the subway section, the tunnel construction causes minimal deformation of the deep excavation support structure and surface. In both cases, the tunnel structure is safe, but in the first case, the displacement of the subway structure is close to the warning threshold value. To reduce the impact of the excavation on the subway structure, the excavation of the foundation must be constructed before the interval structure of the rail transit line construction, otherwise the supporting method should be changed. Before the construction of the deep excavation, numerical simulations can be used to analyze the impact between the deep excavation support and the adjacent subway shield interval, in order to evaluate the adequacy of the design and construction plan. Related Articles | Metrics

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Application of Grouting Method in Highway Bridge Tunnel Construction CHEN Huanmei, SU Wenxuan, YE Mulang 2025, 39 (1):  35-38.  Abstract ( 144 )   Save As an important transportation component, the construction of highway bridges and tunnels plays an important role in the country’s socio-economic development. With the construction of bridges and tunnels, while the number of projects has significantly increased, there have also been situations of uneven settlement, cracks and other hazards after the operation. These potential safety hazards greatly affect the normal use of highway bridges and tunnels. In order to improve the construction technology level and ensure construction quality, grouting method has played an important role in the prevention and control of diseases in bridge and tunnel engineering. This article analyzes the technical content and specific measures of the grouting method commonly used in the construction of highway bridges and tunnels from multiple perspectives. It summarizes the theory and experience of grouting method under different working conditions, providing reference for improving the quality of bridges and tunnels. Related Articles | Metrics

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Construction Measures for Overlapped Shielded Tunnels in Submerged Sand and Gravel Strata DENG Ruyong 2025, 39 (1):  39-42.  Abstract ( 168 )   Save Currently, studies on the construction control of overlapped tunnels passing through complex urban environments in China are mainly focused on demonstrating the effectiveness of construction measures in controlling the surface subsidence. There is relatively little research on the control of overlapped tunnel construction from the source system such as equipment improvement. This paper presents the construction of the overlapped shield tunnel section between the Huancheng South Road Station and the Kunming Railway Station of Kunming Metro Line No. 2. This case history introduces the experience of construction measures for small distance overlapped and shielded tunnel construction under complex geological conditions. The specific auxiliary construction measures include shielded shell thickness reduction, improvement of the shielded cutter-head and the support arm, optimization of the grouting mode behind the wall, strengthening of waterproof sealing at the shielded tail, setting up temporary support in the first construction tunnel. Improving the engineering properties of the soil within the influence range of two tunnels through grouting reinforcement measures. The implementation of the relevant auxiliary construction measures ensures the safety of overlapped shielded tunnel construction in this project. The relevant engineering measures and the implementation experience can provide references and guidelines for similar projects in complex geological conditions. Related Articles | Metrics

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Deformation Impact on Existing Subway with Deep Excavation Construction on Both Sides CHEN Feimin 2025, 39 (1):  43-47.  Abstract ( 173 )   Save The deep excavation construction can cause deformation and accessory stress near existing tunnels, affecting the safe operation of tunnels. This article is based on the deep excavation engineering and establishes excavation models for two working conditions by using a numerical software. The influence of the distance between the excavation and the tunnel on the vertical and horizontal displacement of the existing tunnel is analyzed, and the safe distance between the excavation and the tunnel is estimated. In response to the difficulty of existing subway tunnels passing through deep excavations on both sides, a zoning and block based asymmetric excavation scheme is proposed, following the principle of zoning and block division. Through the onsite monitoring, the deformation curves of the existing tunnel’s vertical deformation and clearance convergence along the tunnel axis were obtained after the deep excavation was completed. Research has shown that as the distance between the deep excavation and the tunnel increases, both the vertical and horizontal displacements of tunnels on both sides decrease to varying degrees, especially during the process of increasing the distance from 10m to 12m. The safe distance between the deep excavation and the tunnel in this project is 12m; The impact of the excavation construction on the deformation of curved tunnels is greater than that of the straight tunnels. The research content of this article can provide a reference for similar projects. Related Articles | Metrics

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Application of Vacuum-covering Combined Prepressing Method in Deep Foundation Treatment of a Sewage Treatment Plant HE Lihong, WANG Xiaonan, LIU Yanling 2025, 39 (1):  48-52.  Abstract ( 156 )   Save The vacuum surcharge method is an economical, environmentally friendly, low carbon emission soil improvement method. This method is carried out through the vacuum pump out the air in the soil, the negative pressure formed in the vacuumed soil can suck the gravity water out through prefabricated plastic drains, sand drains and other vertical drainage system, as well as sand cushions and other horizontal drainage system. Therefore, the soft soil will be consolidated, and compression settlement will occur. In order to accelerate the construction progress, the combined prepressing of covering loading and vacuum loading is often used, namely the vacuum-covering combined surcharge method. The case history of the deep soil improvement in a wastewater treatment plant in Wuhan is presented in this paper. The vacuum-covering joint surcharging method in a deep soil improvement is introduced. The engineering and geological conditions, the design aspects of soil improvement partition, drainage system and construction process, as well as the construction monitoring, are also presented in the paper. Related Articles | Metrics

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Significance Analysis of Influencing Factors on Shear Strength of Steel-Silty Clay CHENG Wenxin, ZHANG Qingyao, ZHANG Qingxin, GUO Jukun, MA Yongming, WANG Rui 2025, 39 (1):  53-57.  Abstract ( 189 )   Save The influence of surface roughness and interface moisture content on the interface shear strength are investigated throughout the interfacial shear test of steel plate and silty clay samples. The significance of factors was compared by using the standardized regression coefficient method. The results show that the greater the roughness, the greater the interface shear strength and its index. With the increase of water content, the interface shear strength and interfacial friction angle gradually decrease, and the interface cohesion first increases and then decreases. The relationship between the interface shear strength and the three independent variables of normal stress, roughness and moisture content conforms to multiple linear regression. Roughness and moisture content have significant effects on the interface shear strength, but the influence of moisture content is greater. The research results can provide a reference value for the interaction between steel piles and silty clay.  Related Articles | Metrics

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CASE Damping Coefficient for the Bearing Stratum at Pipe Pile Tip in a Project Area YUAN Chang, WANG Weize, YIN Huajun, LIU Yongming 2025, 39 (1):  58-62.  Abstract ( 198 )   Save Due to the regional differences in the properties in geomaterials, as well as the influence of pile type, dimension and installation methods, the empirical values for the CASE damping coefficient recommended by major research institutes and instrument manufacturers are lack of precision for geomaterials in some regions.  A typical bearing stratum for the pipe pile (strongly weathered argillaceous siltstone) in a project area was selected to conduct the dynamic and static axial load tests of three pipe piles with different diameters. The CASE damping coefficient of the bearing stratum at the pipe pile tip is back-analyzed, and the influence of the pile diameter on the damping coefficient is analyzed. The results show that the CASE damping coefficient is 0.35~0.55 when the strongly weathered argillaceous siltstone is used as the bearing layer of the pile tip in this area. But the Jc value range of strongly weathered argillaceous siltstone in the same site is more than 30% of the average value, and the data are too discrete, it is shown that the larger the pile diameter is, the smaller the Jc value is. Related Articles | Metrics

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The Foundation Settlement Analysis and Suggestion of a Deep End-Dump Backfill Site in Mountainous Area ZHAO Yunchuan, RAO Chuanyou, Liu Jie, ZHOU Xin 2025, 39 (1):  63-66.  Abstract ( 162 )   Save With the development of urbanization, the methods of mountain cutting, and trench filling are more common in the southwest mountainous area, which is bound to form many landfilling sites. The settlement performance of landfilling sites is an engineering construction concern. In this paper, the site settlement was estimated through drilling, acoustic wave velocity testing and other in-situ testing means as well as using a large number of engineering analogy analysis. At the same time, the deformation modulus of the engineering site and the later possible deformation were also estimated and compared with the actual monitoring results. Although the estimation results are greater than the monitoring results, but it does not affect the overall judgment of the project. After comprehensive analysis, it is concluded that stone cast-fill with good uniformity can be used as the foundation site of power line tower after proper treatment of the shallow surface foundation soil when the filling life is more than 5 years. The estimation and analysis methods of this paper can be used as a reference for the estimation and analysis of similar engineering. Related Articles | Metrics

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Criterion for the Piping of Gravely Soils YAN Jiajie, LIU Tonghui 2025, 39 (1):  67-72.  Abstract ( 163 )   Save At present, the judgment criteria for the stability of the cohesionless soil are too broad, and the applicability to gravelly soil is still to be discussed. Therefore, based on the gravely soil seepage stability test data, the applicability of three commonly used judgment criteria for the cohesionless soil piping (H/F criterion, Wan & Fell criterion, and fine particle content criterion) to the determination of gravely soil piping is analyzed, and the main control factors affecting gravely soil piping are determined by combining data statistics and theoretical analysis. The commonly used criteria are improved and the criteria applicable to the determination of the gravely soil piping are proposed. The research results show that the common judgment criteria for cohesionless soil have a high rate of misjudgment for gravelly soil. The judgment criteria are affected by a variety of soil structure factors, and the main factors that affect the piping of the gravely soil are the nonuniformity coefficient, porosity, the proportion of particle size range, etc. When the nonuniformity coefficient of the gravely soil is greater than 80 and less than 20, the nonuniformity coefficient is the dominant factor that affects the piping of gravely soil. When the nonuniformity coefficient of soil is between 20 and 80, the proportion of different particle size ranges is the main influencing factor. The particle size distribution characteristic parameters used to calculate the boundary particle size of the judgment criteria change with the nonuniformity coefficient and the proportion of different particle size ranges. Related Articles | Metrics

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Numerical Simulation of Settlement Deformation and Stability of Asymmetric Multi-Layers Soldier Piles in Deep Excavation CHENG Feng, LI Qingwang, YANG Dehuan, HE Hui, YANG Bai 2025, 39 (1):  73-77.  Abstract ( 173 )   Save The settlement and deformation in the asymmetric excavation of multilayer deep excavations are important factors affecting the stability of the excavation supporting structures. Numerical simulation of support stability can effectively predict possible problems in the deep excavations. The supporting soldier piles of a subway multi-layer asymmetrical excavation system are analyzed by using the PLAXIS 3D finite element software to construct a wedge-shaped analytical unit. The excavation process of the multi-layer asymmetric excavation is simulated, and the ground settlement, pile top settlement, the horizontal displacement of the soldier pile and the settlement of adjacent buildings and other indicators change are predicted. The deformation monitoring and safety control of the asymmetrical multi-layer excavation are studied. The results show that the horizontal displacement of the pile shaft and the surface settlement increase with the increase of the excavation depth. The settlement of the pile top decreases with the increase of the excavation depth, and the settlement of the adjacent existing buildings decreases with the increase of the distance from the excavation. Numerical simulation results show that the deformation of the excavation is greatly affected by the superstructure, the settlement of the soil near the side of the excavation is about 14% higher than that at the far end, and the horizontal displacement of the soil on the side of the bearing building is about 11% higher than that of the other sides; The comparison results of on-site monitoring and numerical simulation show that the actual deformation process of the excavation is basically consistent with the simulation process, and there is only a slight difference in the stage excavation construction, which shows that the pile-brace joint support method can effectively restrain the deformation of the excavation and make the deformation of the excavation. The index is within the controllable range, and the research results have good engineering guidance for deformation monitoring and safety control during the excavation of asymmetric foundation pits. Related Articles | Metrics

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Analysis of Deep Excavation Influence on the Nearby Operating Metro ZHAO Xing 2025, 39 (1):  78-85.  Abstract ( 156 )   Save The risk of deep excavation near the subway station is high, the in-situ stress will be changed induced by the deep excavation. The hazards are mainly reflected in the deformation and leakage, and further affect the safety and structural durability of subway lines. A three dimensional integrated geotechnical-structural model is established by using finite element method. The effect of the excavation of the deep excavation in newly-built metro station is analyzed. The analysis results show that, although the subway station far from the excavation, the structure of subway station is greatly affected by the excavation, because the foundation structure is more adjacent. Although, the accessory structure of the subway station near the excavation, the structure is less affected by the excavation, because it is far from the deep excavation. The horizontal and vertical displacement of subway station is caused by the deep excavation, due to the ground wall and reinforcement, the displacement of subway station is controlled. Related Articles | Metrics

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Study on the Response of Landslide Stability to Rainfall Infiltration ZHANG Desheng, JIAN Wenbin, XIA Chang 2025, 39 (1):  86-92.  Abstract ( 163 )   Save Rainfall induced landslides frequently occurred in Fujian Province, and it is important to reveal the evolution of landslides triggered by rainfall and its patterns to study the formation mechanism of geological hazards and risk warning criteria in Fujian Province. A numerical model for the Houting landslide in Yongtai County, Fuzhou City, Fujian Province is established and calibrated with field monitoring data to study the changes of landslide seepage field and its stability response under the rainfall effect. The study shows that: (1) the landslide forms a local high negative pore pressure zone under strong rainfall, and causes the water flow to converge to this area, and the response of soil moisture content is positively correlated with rainfall, and the response is timely; (2) the stability coefficient of the landslide decreases rapidly under strong rainfall, and recovers after rainfall, but the recovery rate is much smaller than the decline rate, and cannot recover to the initial value; (3) the strength of the soil decreases after wet and dry cycles, which causes the landslide under the same conditions to stability decreases, so after several rainfall cycles, its stability may decrease resulting in landslides; (4) under strong rainfall, the surface displacement grows steadily and there is still some growth after the rain due to water infiltration. Related Articles | Metrics

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Characteristic Analysis of Negative Friction Resistance of Pile Shaft Caused by Slope Fill DAI Xianyao, WANG Guobin, YE Zhongwen, LU Jie 2025, 39 (1):  93-96.  Abstract ( 147 )   Save To study the mechanical deformation characteristics of pile foundations in slope filled areas, a numerical simulation method was used to study the effects of fill interface slope on negative frictional resistance, neutral point depth, fill surface settlement, and horizontal displacement of piles. The results show that as the slope of the fill interface increases, the negative frictional resistance decreases, the neutral point depth remains basically unchanged, and the surface settlement of the fill before the pile decreases, while the surface settlement of the fill after the pile increases; Therefore, when designing pile foundations, it is necessary to consider the impact of the slope of the fill interface on the axial force and horizontal deformation of the pile foundation. A composite loaded pile with side roots has been developed. The inverted conical plastic film can effectively reduce or even eliminate the impact of negative frictional resistance. The installation of side roots can reduce the settlement of underconsolidated soil, while also improving the ability of the pile foundation to resist horizontal deformation. The research results can provide theoretical support and technical reference for similar engineering design and construction. Related Articles | Metrics

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Impact of Thixotropic on Compression Characteristics of Soft Soils in the Delta from Microstructure View ZHAO Yongfeng, YU Song, YAN Xiaoling, HUANG Juehao, 2025, 39 (1):  97-100.  Abstract ( 187 )   Save The thixotropic property of the soft clay is more significant. The studying in the compressive characteristics of the soft clay under the influence of thixotropic behavior is of great significance for in-depth analysis of the stability of soft soil foundations. The one-dimensional compression tests were conducted on the undisturbed and remolded samples in the Pearl River Delta, then the Scanning Electronic Microscopic (SEM) tests were performed on the samples after the one-dimensional compression tests. The influence of the thixotropy on the compressibility of the soft clay under different standing time and moisture content was analyzed from the perspective of microstructure. The experimental results show that as the standing time increases, the compression curve of the remolded sample gradually approaches that of the undisturbed sample, and the stiffness of the sample gradually increases. The structural shape of remolded specimens gradually tends towards the undisturbed specimens; The microstructure porosity of the sample shows a linear increasing trend with the increase of standing days and water content. When the standing days reach 120 days, the microstructure porosity of the reshaped sample is equal to that of the original sample. Besides that, the particle orientation gradually becomes mainly arranged vertically as the standing days increase. And the distribution intensity gradually increases. The above research results can provide experimental basis for revealing the mechanism of the influence of thixotropy on compression characteristics in soft clay. Related Articles | Metrics

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Investigation and Mechanism Analysis of Deep Karst Collapse in Ping Tang, Qian Nan, China#br# LIAO Youbin, LIU Hong, WU Yuhang 2025, 39 (1):  101-107.  Abstract ( 336 )   Save A well-developed karst development area in Qian Nan Prefecture, Guizhou Province was selected as the research background. A total of eight known collapse sites in the study area were investigated and analyzed. By investigating the relationship between the underground dark river and the distribution of karstic rock caves near the collapse sites, the scale of the collapse body, the lithology of the top plate of the caves and the structure of the rock body, etc., we s〖HJ*4/9〗ummarize the development characteristics of the deep karst bedrock collapse and the mechanism of the collapse. The results show that: (1) the deep karst subsidence in the study area occurs mostly in the area of fracture tectonic development, the subsidence area is more developed in the dissolution fissure and subducting cavern, and the subsidence location is affected by the underground dark river and the subsidence scale is controlled by the structural surface; (2) according to the lithology of the cavern roof plate and the structure of the rock body, this kind of subsidence mode can be summarized into the gravity collapse of the crushing type of the karst roof plate and the gravity collapse of the penetration type of the karst roof structural surface; (3) the subsidence mechanism of the deep karst bedrock is summarized as follows. The depth of the subducted cavern determines the depth of collapse, the degree of fragmentation of the rock body and the development of the structural surface of the cavern roof affects the stability of the roof, and the low stability of the cavern roof is easy to induce the karst collapse when the deep-cut dissolution structural surface is developed. Through the study of this kind of collapse, we have a deeper understanding of the development characteristics and collapse mechanism of deep karst collapse, which will provide some reference for the subsequent collapse early warning work. Related Articles | Metrics

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Research on the Bearing Capacity Characteristics of Steel Pile in Offshore Wind Power Based on Numerical Simulation Method ZOU Changxi, ZHANG Mingjun, WANG Wei, XU Yanbing, XIA Jianguo 2025, 39 (1):  108-112.  Abstract ( 135 )   Save The application of prefabricated steel pipe piles in offshore wind power construction is highly prevalent. The numerical simulation method is employed to investigate the bearing capacity of steel pipe piles and predict the penetration depth during pile driving. A steel pipe pile in an offshore wind power project was selected as an example to establish the numerical model throughout the proper selection of analytical parameters, and determination of the hammering load. The dynamic measurement data of the axial capacity of the steel pipe pile during the construction process was compared with the numerical simulation results to study the axial capacity performance of the pile during the pile driving process. The research indicates that: (1) During the hammer penetration process, the tip resistance and lateral resistance of the pile gradually increase, the penetration rate gradually decreases, the displacement of the pile oscillates, and the tip resistance increases slowly in a "fluctuating" manner. (2) The axial capacity and penetration depth predicted by the numerical simulation method are highly consistent with the measured results, and the simulation accuracy is high. Related Articles | Metrics

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Study on Settlement and Deformation Control of New and Existing Roadbeds in Urban Roads Using Geogrids and Foamed Lightweight Soil ZHANG Zhuo, HUANG Jinsheng, ZHANG Jinhong, ZHOU Shudong, WANG Chengwei, ZHANG Yi 2025, 39 (1):  113-117.  Abstract ( 162 )   Save This study evaluates the effectiveness of different roadbed treatment methods regarding the settlement and deformation of new and existing roadbeds during urban road construction. Using a municipal road project in Huadu District, Guangzhou as an example, a roadbed model including geogrid reinforcement and foam lightweight soil filler was established. The finite element analysis using ABAQUS software was used to conduct simulation with the roadbed construction improved with geogrid and foamed light weight soils. The effect of materials such as lightweight soil in controlling the settlement deformation of new and old roadbeds. Research results indicate that the application of the geogrids at the joints of the existing and new subgrades can significantly improve the stability of the subgrade. However, after reaching a certain number of laying layers, simply increasing the number of the geogrid laying layers has limited effect on improving displacement control. The foamed lightweight soil is used as a lightweight filler. As the filling thickness increases, its control effect on the settlement deformation of the new and old roadbed also becomes significant. Combining the advantages of the two treatment methods and considering the project cost factors, this study proposes a geogrid-foam lightweight soil joint treatment method by laying 3 layers of geogrids in the middle and lower parts of the old and new roadbed and filling the upper part. Foam lightweight soil with a thickness of 2m can effectively control the settlement deformation of new and old roadbeds and improve the overall stability and service life of the roadbed. Related Articles | Metrics

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Review of the Application of Resource Utilization of Red Mud LIU Chang, RAO Junying, MEI Shilong, CUI Hongchao 2025, 39 (1):  118-121.  Abstract ( 258 )   Save Red mud is one of the typical industrial solid wastes, and due to its high alkalinity and potential environmental and social issues during storage or landfill, the industry urgently needs to explore the path of resource utilization of red mud. This article summarizes the research results on the resource utilization of red mud both domestically and internationally: (1) recovering valuable metals such as scandium, titanium, aluminum, etc. from red mud, using methods such as direct physical separation and reduced magnetic separation; (2) Using red mud to prepare building materials, such as road base materials, cement, and asphalt; (3) Using red mud for environmental protection, such as absorbing heavy metal ions and radioactive substances from wastewater, treating waste gases such as SO2, CO2, and sulfuric acid mist in the atmosphere, and adsorbing heavy metal ions from soil. Summarized and analyzed the characteristics of different recycling and utilization technologies for red mud, pointed out some of the problems, and put forward some suggestions. The future direction of resource utilization of red mud has been clarified, and scientific research should be carried out with the goal of reducing, harmless, and industrialized utilization of red mud. Related Articles | Metrics

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Curvature Effect of Curved Surface Shear Strength for Coarse Grained Soils FENG Haihua, LU Yong, HUANG Hui 2025, 39 (1):  122-126.  Abstract ( 175 )   Save In practical geotechnical field, failure planes are always 3D curved sliding surface. Their mechanical characteristics are different from the typical flat failure plane. Curved surface shear test is taken to consider the effects of failure plane’s curvature to the shear strength of coarse-grained soils. The results show that the shear strength grows nonlinearly with the curvature radius’ growth of shearing surface, this phenomenon is defined as the effect of curvature to curved surface shear strength. The results also show that the effect of curvature is obvious in a certain range of vertical stress, and the effect will be weakened and eventually disappeared as the vertical stress increasing. Finally, the ideal sphere model is used for qualitatively analyzing the mechanism of curvature effect and the relationship between effect and grain size and particle crushing under high pressure. It also points out the prediction of the disappearance of curvature effect in fine-grained soil and under high pressure.  Related Articles | Metrics

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Study on Impermeability of a Modified Calcium Carbide Slag BIAN Xiaoran, HUANG Shufu 2025, 39 (1):  127-130.  Abstract ( 145 )   Save Using the calcium carbide slag to construct soil overburden to realize waste treatment has important engineering application value. To explore the feasibility of modified calcium carbide slag as a covering material, the saturated permeability coefficient, gas diffusion coefficient and permeability coefficient of bentonite samples mixed with calcium carbide slag of a certain mass were measured by a variable head permeability test device combined with a gas diffusion permeability coefficient tester. The results showed that as the bentonite content increased from 5% to 15% (mass fraction), The saturated permeability coefficient of the sample decreases gradually. When the bentonite content is more than 10%, the saturated permeability coefficient is less than 1×10-9 m/s, which meets the requirements of the impermeable layer of the covering layer. When the bentonite content is 10%, the gas and diffusion permeability coefficients of the sample decrease significantly with the increase of saturation. When the saturation is more than 85%, the sample has good gas retention performance. Related Articles | Metrics

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Application of High-Density Electrical Method in Urban Underground Piping Investigation ZHANG Zhaobin, SONG Pengbo, HAN Wenyong, ZHAO Haichao, LI Huili, WANG Kun 2025, 39 (1):  131-133.  Abstract ( 167 )   Save Through the analysis of geological and geophysical characteristics, geophysical forward numerical simulation and actual electrical structure analysis, it is concluded that the electrical structure characteristics of urban underground “piping” are resistivity cascade zone fusion area, low resistance area is inferred to be filled water "piping" channel, high resistance area is inferred to be dry or unfilled water “piping” channel. The resistivity cascade zone with slow variation, low resistance zone and high resistance zone are inferred as potential “surge” channels. Because the inversion estimation of geophysical results has multiple solutions, it is suggested to combine geological data for comprehensive analysis. Therefore, the application of high-density electrical method to investigate the spatial distribution of urban underground “piping” has great guiding significance for solving the existing safety problems in advance, as well as for the development, management and comprehensive utilization of urban underground space. Related Articles | Metrics

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Application of Testing and Evaluation Method for Existing Foundations LEI Yongyu 2025, 39 (1):  134-138.  Abstract ( 154 )   Save The Gansu Tianshui Qilidun 110 kV substation was completed and was in operation in 1984. It is located in Qilidun, Qinzhou District, Tianshui City, Gansu Province. The substation is mainly responsible for the power supply of three traction transformers on the electrified railway of the Longhai Line in Qinzhou District, Maiji District, and some areas of Longnan City. In combination with the expansion project of the main transformer of the Gansu Tianshui Qilidun 110 kV substation, this article mainly introduces the comprehensive application of existing foundation testing and evaluation methods that have a long history and no clear design data; In the face of complex situations such as surrounding environment, high voltage lines in the air, and environmental electric fields, traditional, economical, and safe testing methods such as dynamic cone penetration test (DCPT), real-time kinematic measurement technology, and rebound method concrete compressive strength test are selected to analyze and evaluate the later reuse performance of existing foundation; And explained the technical characteristics and advantages and disadvantages of the three testing methods, which have good application effects. Related Articles | Metrics

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Experimental Study on the Shear Strength of Tea Tree Root-Soil Composite XU Shaohong, CHEN Lingqi 2025, 39 (1):  139-143.  Abstract ( 164 )   Save In this paper, the effect of different root content, root diameter and root distribution patterns on the shear strength of the root-soil complex was investigated, and the changes in cohesion and internal friction angle were quantified. The test results show that the interaction between tea tree roots and soil is stronger than that between bare soil, and the soil forms a stronger composite. The shear strength of the soil increased with the increase of root content, and the increase of internal friction angle was significantly higher than that of cohesion, when the root content was 1.0%, the increase of shear strength was about 29%, and the increase of internal friction angle was as high as 31.8%; as the root diameter increases, the shear strength of the soil gradually increases; the differences in root distribution patterns lead to different patterns of shear strength increase, with mixed rooting increasing the shear strength of the specimen by approximately 10% compared to horizontal rooting, and vertical rooting increasing the shear strength by approximately 4% compared to horizontal rooting. Related Articles | Metrics

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Shear Strength Characteristics of Unsaturated Expansive Soil Improved by the Weathered Sand WANG Yangsheng 2025, 39 (1):  144-149.  Abstract ( 159 )   Save The engineering background of this article is the subgrade construction of a highway in Hefei, where the soil category is expansive soil. To get closer to the real environment of the soil mass and clarify the change rule of the shear strength of the soil mass after the improvement of weathered sand, the matrix suction, initial dry density and confining pressure are taken as the control parameters to conduct triaxial shear test on the improved soil, and analyze the shear strength parameters, and study the change rule. The test results show that: ① the stress-strain curve of the improved unsaturated expansive soil presents a hyperbolic hardening model, and the tangent slope of the stress-strain curve, that is, the growth rate of the linear elastic modulus, is negatively correlated with the confining pressure; ② The effect of initial dry density on shear strength is less than that of the confining pressure change; ③ The improvement effect of weathered sand on expansive soil mainly comes from the improvement of its internal friction angle; The matrix suction has an effect on the apparent cohesion of the structure, but has little effect on the internal friction angle; Under this specific engineering background, the formula of double stress shear strength of unsaturated soil is simplified to facilitate practical application; ④ The linear regression of the failure strength of improved soil under the joint action of three parameters, namely initial dry density, matrix suction and net confining pressure, has a good effect, providing technical parameter reference and stability basis for subgrade slope engineering improvement in expansive soil area. Related Articles | Metrics

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Monitoring and Analysis of Seepage Flow in a Reservoir in Ganyu County ZHANG Yuting, QU Shengjun, ZHANG Bohang 2025, 39 (1):  150-153.  Abstract ( 249 )   Save One of the major objectives of the reservoir project is to provide domestic and industrial water for Shiqiao Town, Zhawang Town and Zhawang Lingang industrial area of Ganyu County as well as considering the regional flood control and the farmland irrigation. The reservoir is in the water related environment for a long time, subjecting to the action of highwater head, the dam body is seriously damaged. It is of great significance to understand the seepage state inside the dam structure. Therefore, it is particularly important to monitor the seepage stability of reservoir by using the pressure measuring pipe. The pressure measuring pipe is an old and common seepage monitoring instrument, which depends on the height of the water column in the pipe to indicate the magnitude of the osmotic pressure. It can be used to monitor the seepage line, osmotic pressure, groundwater level and the seepage around the dam. This instrument is widely used in the water conservancy, petroleum, chemical industry, construction machinery manufacturing, coal mining and other industries. This paper describes the buried and sensitivity test of the pressure measuring pipe, observes the water level of the pressure measuring pipe, and judges the safety of the reservoir by analyzing the wetting line.  Related Articles | Metrics

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Model Test of Axial Capacity and Deformation of Pile-Net Composite Foundation Under Traffic Load CAI Yonghao, XUE Kairen, LIU Kaifu 2025, 39 (1):  154-158.  Abstract ( 150 )   Save To study the axial deformation characteristics of pile-net composite foundation under the traffic load, a model tests of the pile-net composite foundation were performed under the cyclic loading. The influence of the load frequency on the normalized cumulative settlement of the pile-net composite foundation, pile strain and pile-soil load sharing ratio are analyzed. The results show that the normalized cumulative settlement, the pile strain and the pile load sharing ratio of the pile-net composite foundation increased with the increase of the number of cyclic cycles. The normalized cumulative settlement and the pile strain of pile-net composite foundation is mainly concentrated in the early stage, and the increase slowly in the later period. With the increase of the load frequency, the normalized cumulative settlement and the pile strain of pile-net composite foundation increased, and the load transferred from soil between piles to the pile top. The research results can provide a basis for the design and construction of the pile-net composite foundation under the traffic load. Related Articles | Metrics