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30 April 2025, Volume 39 Issue 2 Previous Issue    Next Issue

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Deformation Characteristics of Large Sized Foundation Excavations with Various Types of Support in Soft Soil Areas#br# ZHANG Wei, XU Shengjun, ZHANG Zhenyu, ZHANG Bailiang, WU Xi, SUN Miaomiao, 2025, 39 (2):  159-165.  Abstract ( 191 )   Save The deformation characteristics of the long and large sized foundation excavation with various types of excavation supports in soft soil areas are analyzed in this paper. The construction monitoring data of the soil settlement, the retaining structure deformation, and the axial force of the bracing system are collected for a project in Hangzhou. The long and large sized foundation excavation retaining structure under different support types was comprehensively analyzed and evaluated. The results show that both bored piles and the SMW method columns can effectively control the deformation of the excavation. The deformation control capability of the enclosure structure under the combined application of different foundation support types presents a strong uniformity and the deformation of the enclosure structure on both sides of the junctions is continuous. The combined application of different foundation excavation support types can meet the design and construction requirements, and the structural deformation of the foundation excavation can be controlled within the scope of the code requirements. The engineering practice can provide a construction experience and the practical basis for similar projects in the future. Related Articles | Metrics

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Deformation Mechanism Analysis and Reinforcement Design of the Left Abutment Slope of Yangfanggou Hydropower Station PAN Bing, ZHOU Yong, CHU Weijiang, YIN Liang 2025, 39 (2):  166-171.  Abstract ( 220 )   Save The geological conditions of the left abutment slope of Yangfanggou Hydropower Station are complex, and the unloading effect in the rock mass developing with slope-oriented steep-gentle-dipped fractures is strong. During the excavation of the slope, the deformation and the cracking response in the rock mass on the upstream side of the arch dam foundation are observed, the stability of the slope and personnel safety have been significantly affected. Based on the engineering geological survey and monitoring data analysis, a discrete element simulation model is established for the deformation mechanism and the crack cause analysis of the left abutment slope. The numerical analysis results show that: the fault f27 and the slope-oriented structural plane with gentle dip are the main factors that influencing the deformation response during excavating the slope. During the excavation of the slope above E.L.2000 m, the f27 has an obvious influence on the local stress at the toe of the slope. The stress will be concentrated in the upper part of f27 firstly and then unloading and relaxed under the combined action of the slope-oriented structural plane. The shear deformation happens along with the fault f27, and the subsidence of its hanging wall caused the crack of the rock mass. The slope stability will be significantly reduced with the f27 exposed on the excavation face, there is a large risk of slip and instability. The pre-stressed ground anchors are used to establish the toe and strengthen the middle of the slope, which can effectively improve the stability of the slope and control the shear deformation of f27. After the prestressed ground anchors are applied, the safety factor of the slope is increased from 0.98 to 1.20, and the monitoring data show that the deformation is controlled successfully. Related Articles | Metrics

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Analysis and Mitigation Measures of Subgrade Instability in Soft Soils Adjacent to Mountain ZHANG Yinqiu, HU Zhikang, HU Chengbao, CHEN Jiawang 2025, 39 (2):  172-176.  Abstract ( 139 )   Save Stabilizing soft soil roadbeds in mountainous areas is a difficult problem in highway engineering. The pavement cracks on a coastal expressway soft soil section along the mountain side are observed. Combining with the relevant engineering data, the stability of the soft soil roadway is back analyzed at a critical section by using the Plaxis finite element method and the influence of different soft soil treatment measures on the subgrade stability is evaluated. The results show that the geological conditions of the soft soil section near the mountain are not uniform in longitudinal and transverse directions, and the potential sliding surface is more easily induced by the climate and the rainfall, which causes the phenomenon of subgrade destabilization. For the secondary reinforcement of the soft soil subgrade with complicated geological conditions, mitigation measures such as cement mixing columns, anti-slide caissons and high-pressure jet grouting columns can avoid and minimize the subgrade sliding hazards. The method of anti-slide caisson plus high-pressure jet grouting columns can effectively reduce the settlement of the subgrade and improve the stability of subgrade with the limited land use, which can provide reference for the future mitigations of the soft soil subgrade. Related Articles | Metrics

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Dimension Design Optimization Analysis of the Rectangular Soil Improvement Zone in the Passive Resistance Area of Deep Excavation YU Fan 2025, 39 (2):  177-180.  Abstract ( 130 )   Save The Soil improvement in the passive resistance zone of deep excavations can improve the embedded conditions of the supporting structures in the passive area, strengthen the control of the horizontal displacement of the support structure as well as the subsidence of the surface soil after the excavation, which is a common reinforcement measure for the deep excavations in thick, soft soils. The soil improvement design in the passive resistance zone of a deep excavation in the thick and soft soil area in Jingzhou City is presented in this paper. The commercial finite element analysis software of geotechnical engineering is used to analyze the improvement effect of the passive resistance zone under different improvement sizes. The results show that using the maximum displacement of the soldier pile as the control indicator, the width and the depth of the rectangular improvement of the soil in the passive resistance zone have the optimal design range values. When the improvement width and depth are not in the optimal design range values, the required improvement volume increases significantly, which can play a valuable reference for the design of the improvement of the passive resistance zone of the deep excavations in soft soils. Related Articles | Metrics

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Design and Application of Pile Anchor Support System in Deep Foundation Pit Support Near Massif LU Junsen, CHU Wei, PENG Peng, DAI Ye 2025, 39 (2):  181-187.  Abstract ( 168 )   Save A deep excavation supporting structure is location in the Donghu High-Tech Economic Development Zone of Wuhan City. The proposed excavation is close to a permanent slope with a height of 20 meters and the proposed excavation depth varies from 15 to 20 meters. When the excavation is completed, there is a 40 meters elevation difference between the crest of the slope and the bottom of the excavation. Therefore, the safety of the supporting structure and the excavation sequence area critically important. This paper presents a combined design of the excavation supporting structure combined with the high slope stability mitigations. The slope near the excavation is stabilized with the retaining wall and ground anchors and the excavation supporting structure is designed to use the prefabricated concrete soldier piles with ho rolled steel beams with ground anchors. The ground anchor design considers the impact of nearby high slope. During the construction. The deformation of the excavation supporting system and the adjacent soils are monitored and compared with the design values. The monitoring results indicate that the measured data are consistent with the predicted values. It is concluded that the design approach is reasonable and the project can provide a valuable reference for the future similar projects. Related Articles | Metrics

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The Application of ABAQUS in an Existing Structure Tilting Mitigation Project ZHU Sixiang, WEI Xiaojing 2025, 39 (2):  188-191.  Abstract ( 198 )   Save The structural rehabilitation and the tilting mitigation of a seven-story residential building are presented in this paper. The application of commercial finite element software ABAQUS in the designing of the tilting mitigation program and how ABAQUS software achieved the design optimization of program are also discussed in detail. The reasonable pile space and the optimal length of pile are determined from the numerical analysis. Under the background of the national “two-carbon minimization” strategy, through the optimization design of the structural rehabilitation and building tilting mitigation, the overall carbon emissions are effectively reduced while the purpose of the rehabilitation and the tilting mitigation are achieved. After the project, the tilting value of the existing structure is reduced from the maximum of 125mm to 10 mm, and the final tilting ratio satisfies the requirement of national code. The implementation of this project can provide a valuable project case history and a technical reference for the design and mitigation of similar projects. Related Articles | Metrics

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Evaluate the Improvement Effect of Soft Soils Using On-Site Monitoring Data LIU Kelun 2025, 39 (2):  192-195.  Abstract ( 107 )   Save The improvement effect of using the prefabricated vertical drains with surcharge preloading method to treat the soft soils are presented in this paper. Combined with a soft soil improvement project in Jiangmen City, the monitoring data of surface settlement, extensometer results, pore water pressure and other monitoring information were analyzed. The research results show that: (1) It is unreasonable to use a single settlement rate to determine the results of the improvement, and it is necessary to comprehensively consider a variety of deformation indicators. (2) In the range of 2~12 meters below the ground surface, the compression rate of each soil layer is 6.36~9.56%, and the compression amount accounts for 62.4% of the total settlement. The maximum compression rate is 6 meters below the ground, not at the ground surface. (3) At the end of preloading stage, the dissipation rate of excess pore pressure is close to zero, but there is still residual pore pressure at a deeper level. The research results of this paper can provide a valuable reference basis for the design of regional soft foundation. Related Articles | Metrics

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Influence of the Deep Excavation Construction of a Commercial Complex on the Adjacent Subway Tunnels ZHAO Yue 2025, 39 (2):  196-199.  Abstract ( 168 )   Save The urban subway is one of the important means to mitigate the traffic congestion, and the number of subway lines also represents the development status of the city. However, subway tunnels are more sensitive to changes in the surrounding environment, so it is crucial to study the impact of deep excavation construction on nearby subways. This article is based on the TOD Tianjie deep excavation project of Longhu New East Station. The excavation process is simulated using commercial software MIDAS/GTS, and the deformation of the tunnel structure during the deep excavation process is evaluated. The stress of the tunnel structure is checked and predicted. The results indicate that there is a significant change in the surface settlement during the installation of the third and fourth layers of ground anchors at the supporting structure. Special attention should be paid to the deformation of the excavated area and the tunnel structure during this construction phase; The maximum settlement and the maximum horizontal deformation of the tunnel structure are linearly related to the number of excavation steps, but the maximum horizontal displacement deformation is more obvious. To meet the design requirements, the internal force of the tunnel segments during the excavation process meets the original design requirements for the ultimate bearing capacity. The research results provide a basis for the construction of deep excavation adjacent to existing subways and reduce the impact of deep excavation construction on the surrounding environment. Related Articles | Metrics

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Stabilization of Steep and High Rock Slopes with Hard and Soft Strata Interbedded YANG Tao, YANG Zhijiang, YAN Yonghui 2025, 39 (2):  200-202.  Abstract ( 166 )   Save The soft hard alternating bedded rock slopes often experience sliding failures along the soft rock layer due to the formation of weak structural planes induced by the weathering or the softening of soft rock in contact with water. A high and steep rock slope was formed by excavation at a cement plant in Jinan. The rock type of the slope is mainly composed of shale and limestone from the Gushan Formation of the Jiulong Group. The shale is in a thin layer, severely weathered, and prone to degrade to soils when encountering water. It is a weak layer, and the inclination of the rock layer is similar to that of the slope, with an inclination angle smaller than that of the slope. The current stability status of the slope is investigated and analyzed. Hazards such as the falling blocks on the slope surface, cracks at the top of the slope, and water leakage during the rainy season are addressed. The mitigation measures include vertical beams, ground anchor with shotcrete support, and interception and drainage measures to comprehensively mitigate the slope stability issue. After one year of operation, the slope deformation meets the specifications and design requirements, and the treatment effect is satisfactory, which has a reference significance for similar projects. Related Articles | Metrics

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Measures for Mining Method Construction of Subway Turnback Line in Complex Environment WANG Wenhui 2025, 39 (2):  203-207.  Abstract ( 129 )   Save The Changsha Metro Line No. 3 is a subway line that has in operation. The underground excavation and turnaround section of the Dongtang Station is a double track large-span length section constructed by mining method. Along the tunnel alignment, there are dense distributed buildings in the surrounding area, and there is no convenient site to set up vertical shafts to create working faces. The top of the tunnel is close to highly permeable pebble formations, and the geological conditions are poor. After a detailed on-site survey, the vertical shaft was finally chosen to be in the middle of the road, avoiding roadside trees. The enclosed area is narrow and small, making construction difficult. The side is adjacent to a parallel synchronous excavated and shielded tunnel, which belongs to a high-risk tunnel project in the bustling area of the city center. The vertical shaft half rode over the mining method excavated tunnel, carefully optimizing the excavation and backfilling plan of the tunnel vertical shaft, handling measures for the parallel excavation operations adjacent to the shielded tunnel and briefly describing the emergency of the water leakage risks in the vertical shaft and underground excavation. Finally, overcoming difficulties, the implementation of the underground excavation tunnel was successfully completed, providing a good reference for the similar construction projects in the future. Related Articles | Metrics

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Risk Prediction and Control of TBM Machine Crossing A Fault Zone JIAN Yilin, LIU Xialin, PENG Wenbo 2025, 39 (2):  208-212.  Abstract ( 165 )   Save The risk prediction and emergency mitigations of the TBM excavation jamming have become the key control points for an efficient tunneling project. The service tunnel of the Tianshan Shengli Tunnel uses an open-type TBM for the excavation, and the tunnel passes through 16 faults, which poses a high risk of jamming the TBM. For the fault zones with potential jamming risks in the Tianshan Shengli Tunnel, a jamming prediction method based on the deformation prediction of fault zones and the TBM enlargement volume was established, and it was applied to the jamming prediction of the Tianshan Shengli Tunnel to analyze the degree of jamming risk in each fault. The effect of the grouting consolidation of fault zones was studied, it provides advanced reinforcement technology for the TBM tunnel. When the TBM needs to be released, chemical grouting, bracing with grouting pipes, detour tunnel, and tunnel excavation and unloading measures can take together to ensure a safe construction. By conducting the risk prediction before the TBM construction, take specific measures to the fractured zone of fault in tunnel, provide reinforcement measures during the construction. After the TBM is jammed, take reasonable mitigation measures, so that the TBM construction in the tunnel is safe and efficient. Related Articles | Metrics

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Impact of Navigation Channel in Deep Soft Soil Sites on the Stability of Adjacent Bridge Pile Foundations and Surrounding Soils LI Feng, DING Wanpeng, CHEN Zhaoyu, WU Zhijian, 2025, 39 (2):  213-217.  Abstract ( 143 )   Save To investigate the impact of the navigation channel on the stability of the adjacent pile foundations and surrounding soils, a typical bridge project of the second channel of the Beijing Hangzhou Grand Canal was taken as the research object. Numerical analysis methods were used to investigate the influence of the soil excavation and the channel water injection on the deformation of the adjacent bridge pile foundations and the water pressure of the surrounding soils. The results indicate that excavation of the soil will lead to a decrease in the soil water pressure, and the deeper the soil is buried, the more significant the change in the water pressure caused by the excavation. The excavation of the channel soil will cause the horizontal displacement of the pile foundation towards the channel side, affecting the stability of the pile foundations. As the water injection height of the channel increases, the water pressure of the soil inside the channel gradually increases, and the water pressure of the soil outside the channel shows a trend of first decreasing and then increasing. Moreover, there is a lag effect of the water injection on the water pressure supplement of the soil in the channel. The water injection into the channel will significantly affect the horizontal displacement of the pile foundation of the overpass bridge. The smaller the pile depth, the greater the impact of the water injection into the channel on the horizontal displacement. Related Articles | Metrics

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Stability Analysis of a Slope in a Large Earthwork Disposal Site in Guangxi Province FANG Guoqiang 2025, 39 (2):  218-221.  Abstract ( 127 )   Save The stability of the slope at a large earthwork disposal site in Guangxi Province is analyzed through the on-site investigation and the preliminary geological data. The lithology and geological structure of the disposal site are identified. The laboratory direct shear tests provide the mechanical properties and strength parameters of the soil in both natural and saturated states. Based on all above information, the drainage capacity of the ditches in the disposal area and the stability of the slope under different operational conditions are studied using standard verification and limit equilibrium methods. The results show that the surface drainage capacity of the ditches in the disposal area is 15.93 m3·s-1, slightly higher than the calculated peak flood flow of 14.31 m3·s-1 in the catchment area, with a safety margin of about 13%. It is recommended to plant grass for vegetating in the disposal site and regularly inspect the integrity of the drainage ditches. The minimum safety factor values for the slope under the normal operating conditions, special operating conditions I, and special operating conditions II are 1.56, which is higher than the standard value. This indicates that there will be no local or overall deformation failure in the waste disposal area, nor will there be overall failure along the original ground surface interface. The potential sliding surfaces of the slope mostly appear at the top of the first-level platform and the retaining wall. Daily inspections should pay special attention to deformation and cracks at the top of the retaining wall and the first-level platform. Related Articles | Metrics

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Simulation of Foundation Improvement Using Cemented Soil Constitutive Model ZHU Yongkang, ZHOU Ya, HU Xiaozhu, FENG Haihua 2025, 39 (2):  222-227.  Abstract ( 144 )   Save In the geotechnical engineering, to ensure the safety and stability of soil mass, the Portland cement is often added into soil to form artificially cemented structured soil (improved soil), which is widely used in the improvement of mechanical properties of poor soils. In this paper, the finite element program using the cemented soil constitutive model is used to simulate the soil improvement process. Although the cementation at the bottom of the footing area can improve the bearing capacity of the foundation soils, the stress concentration phenomenon will occur, and the safety of the foundation system cannot be well guaranteed. The effect of the cementation in the distance away from the footing is limited. The suitable area under the bottom of footing is selected for cementation improvement. The soil layer between the footing and the cementation reinforcement area can act as a “cushion”. This cushion transfers the footing pressure to the cementation improvement area more evenly. In this way, the cementation within the improved area can be maximized. The bearing capacity of the foundation can be significantly improved. The safety of the footing is warranted even if the foundation is more deep embedded. Related Articles | Metrics

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Stability Analysis of River Revetments in Urban Complex Environment HUANG Xiaojuan, XIA Chang, JIAN Wenbin, FAN Xiufeng 2025, 39 (2):  228-233.  Abstract ( 151 )   Save As a building (structure) that protects the riverbank below the ground along the river, the revetment is also an important support for the river to function, and the city river’s bank slope is safeguarded by its stability. There are many inland rivers in Fuzhou, and the instability of the revetment has occurred in recent years due to the complex hydrological and environmental influences such as typhoon and rainstorm, inland water diversion, and urban environment. In this paper, the influence of main factors on the stability of the revetments is analyzed by investigating the depth of river dredging, the variation of the inland water level, and the height of stacking on top of the revetment retaining wall and establish a geological model of revetments. The results of the study can provide a basis for the stability risk evaluation and the improvement of the revetments in urban inland rivers. Related Articles | Metrics

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Stability Evaluation of Disposal Slope by Three-Dimensional Limit Equilibrium Method TANG Zhijun, WANG Yan, LV Bowen 2025, 39 (2):  235-240.  Abstract ( 140 )   Save Most of the mountain highway waste soil disposal sites are in the valleys with complex terrain. If these disposal slopes are not handled properly, they will not only destroy the ecological environment but also threaten the life and property safety of downstream residents. Therefore, their stability needs to be evaluated. The “Y” shaped disposal slope of an expressway is selected for the evaluation. In order to overcome the deficiency of the conventional two-dimensional profile analysis in the evaluation of the global stability of the slope, a triangular prism solid model is constructed with the original surface as the potential sliding surface. The stability is analyzed by the three-dimensional limit equilibrium Hovland method. The results show that the topographic distribution characteristics such as the slope and the slope direction at different parts of the sliding surface of the “Y” shaped disposal site and the spatial relationship between the slope direction and the main sliding direction cause the stability of the triangular prism units at different positions on the sliding surface to be different. The distribution patterns of the triangular prism units with different safety factors constitute the sliding area and anti-sliding area. According to the characteristics of the valley waste soil on both sides of the “Y” shaped disposal site squeezing towards the middle, the global safety factor of the disposal site under the natural and rainfall conditions is further analyzed. The results can meet the requirements of the specification. Compared with the conventional two-dimensional limit equilibrium and the finite element numerical analysis methods, this method can intuitively obtain the global stability coefficient of the “Y” shaped disposal slope, provide a basis for the subsequent hazard mitigation. Related Articles | Metrics

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Key and Difficult Issues in Engineering Land Reclamation Practice in Hilly and Gully Loess Areas DONG Chenfan, ZHANG Ruisong, HE Jiandong, TANG Hui 2025, 39 (2):  241-245.  Abstract ( 178 )   Save In the early planning stage of land reclamation in Yan’an New Area, some geotechnical engineering experts proposed suggestions on the engineering geological hazards that Yan’an New Area will face. Currently, the first phase of the earthwork construction in Yan’an New Area has been completed for about 7 years. Based on the initial suggestions and monitoring results after the construction completion, the Pingshan land reclamation project in Yan’an New Area has achieved success. This article summarizes the theoretical and practical experience of loess high fill. At the same time, a review and an analysis were conducted on the handling of key and difficult issues in various stages of the earthwork. Experience was summarized on the key and difficult issues of geotechnical engineering that have received great attention from several aspects, such as quality control of the backfill operation, design of the high slope treatment, design of the underground drainage body, the treatment of collapsible loess, and the foundation treatment of the gully bank slopes. This provides a guidance and a reference for similar projects in the future. Related Articles | Metrics

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Stability Simulation of a Slope Using Strength Reduction Method and Comparison LOU Yueyue, HUANG Hui, LU Yong, CAO Meng 2025, 39 (2):  246-250.  Abstract ( 154 )   Save There are many natural hazards caused by the slope instability, in this paper, the stability simulation of a clayey slope using the strength reduction method is compared with the theoretical method. A better way to predict and to prevent hazards caused by the slope instability in advance are obtained through the numerical analysis. In this paper, the numerical simulation software ABAQUS is used to establish the prediction model. Then, the theoretical method includes Sweden slice method and the Bishop’s slice method are used to evaluate the model. Through the comparative analysis, the results of ABAQUS numerical simulation software are very close to the theoretical methods, but the numerical simulation is more convenient and fast, and the stability and the safety factor of the slope can be obtained directly without assuming the position of the sliding surface in advance, and the displacement, stress and plastic zone of each point of slope at different times can be obtained. Related Articles | Metrics

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Influence of Silty Soil Layer Thickness and Soldier Pile Insertion Ratio on Deep Excavation Deformation ZHU Jinbing 2025, 39 (2):  251-255.  Abstract ( 195 )   Save Due to the different thickness, the silty and peaty soil layer can have a significant impact on surface settlement and deformation of the supporting structure. The different insertion ratios of soldier piles can also affect the stability and safety of the excavation. Therefore, to understand the influence of the thickness of the silty and peaty soil layer and the insertion ratio of the soldier piles on the horizontal deformation and surface settlement of the supporting structure, a numerical model was established for the analysis and compared with the measured results. The research results showed that the maximum horizontal deformation of the supporting structure increased with the increase of the thickness of the silty and peaty layer, and the maximum deformation of the supporting structure reached 41.3 mm when the thickness of the silty and peaty soil layer was 20 meters; The horizontal deformation of the supporting structure under each thickness of the silty and peaty soil layer shows a trend of first increasing and then decreasing with the increase of depth. The larger the thickness of the silt layer, the more obvious the trend of deformation increasing or decreasing; The amount of surface settlement increases with the thickness of the silty and peaty soil layer, reaching a maximum of 31.33 mm when the thickness of the silty and peaty soil layer is 20 meters; The horizontal deformation value of the supporting structure gradually decreases with the increase of insertion ratio; When the insertion ratio is below 0.51, reducing the insertion ratio will greatly increase the horizontal deformation value of the enclosure structure; When the insertion ratio does not exceed 0.511, the increase in the maximum settlement gradually becomes apparent. The maximum surface settlement increased by 15.08 mm when the insertion ratio decreased from 0.384 to 0.256, with an increase of nearly 28.6%. Related Articles | Metrics

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Study of the Influence of Continuous Karst Rock Cavities on the Subway Tunnel Construction GUO Shulan, YAN Changhong, YU Liangchen, WANG Pengbin, PENG Chaolin, YAN Chao 2025, 39 (2):  256-261.  Abstract ( 151 )   Save The urban traffic congestion is becoming more and more serious, and the rail transit has become an important development trend to relieve the pressure of the urban traffic. In recent years, a series of shallow buried continuous karst rock cavities have been encountered in the urban subway construction in southern Jiangsu Province. Based on the summarizing of a large amount of geological exploration data, it is found that there are four types of shallow buried continuous karst rock cavities. Combined with the development characteristics of the continuous karst rock cavities and the buried depth range of the subway shielded tunnel in southern Jiangsu Province, the mechanical characteristics of the tunnel excavation and the karst rock cavity stability are analyzed by the numerical simulation method. It is found that with the excavation of the tunnel, the displacement of the vault and the arch bottom of the tunnel increases obviously, and the slope of the displacement curve gradually becomes steep, which indicates that the displacement release rate will increase by the excavation of the karst rock cavities. The deformation caused by the development of the continuous karst rock cavity at the bottom of the tunnel is far greater than that caused by the development of the karst rock cavity at the top of the tunnel; the deformation is the largest when the type IV continuous karst rock cavity is developed at the bottom of the tunnel; when the karst rock cavity is developed at the top of the tunnel, the influence of type III continuous karst rock cavity on the deformation of the tunnel and surrounding rock mass is the greatest; when the karst rock cavity is located at the bottom of the tunnel, the maximum value of the maximum principal stress appears in the tunnel shoulder and waist, which is an asymmetric distribution; when the karst rock cavity is located at the bottom of the tunnel, the maximum value of the principal stress appears at the top of the tunnel, and the stress is concentrated and distributed symmetrically. At the same time, the targeted mitigation measures are proposed for the four types of continuous karst rock cavities in southern Jiangsu Province. The research results can provide the necessary technical support for the tunnel construction in the shallow buried continuous karst rock cavity area, and have a direct significance for the scientific and the quantitative design and the construction of the tunnel. Related Articles | Metrics

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Study on the Basic Evaluation Index System of Photovoltaic Supports Using Analytic Hierarchy Process ZHENG Chuan, GUO Jingcong, ZHANG Zeyu, DENG Xinliang, ZHANG Xiangxiang 2025, 39 (2):  262-266.  Abstract ( 143 )   Save The photovoltaic industry has developed rapidly, but the research on the basic selection of the photovoltaic brackets is relatively small. The assessment index system is not perfect. This article summarizes the main factors that affecting the foundation of photovoltaic stents, establishing comprehensive aspects of the basic assessment index system to help decision making during the basic selection process of the bracket. The use of hierarchical analysis to quantify the indicator system, to analysis the impact of each evaluation indicator on the basic selection of the bracket are evaluated. The results of this study show that, at the primary level of assessment, “basic stability”, “cost”, and “constructability” hold the most significance. When the decision making regarding the selection of the bracket foundation, these three aspects should be given the utmost considerations. Among them, the “stability of the load”, the “stability of conventional loads”, “construction technology cost” and the “construction period quality” carry the greatest weight, making them the most influential factors in the bracket foundation selection. The results fulfill the research gap in the field of basic selection of photovoltaic brackets, provide useful tools and methods for related fields, and are expected to improve the basic quality and economic benefits of photovoltaic power station projects. Related Articles | Metrics

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Slope Classification Method Based on the Deformation Evolution Process ZHAO Kaiyi, LI Cong, CAI Weizhen, ZHANG Xinzhou, WU Liangliang, XIE Tian 2025, 39 (2):  267-271.  Abstract ( 139 )   Save A systematic classification system has been established in the slope engineering, and corresponding standards and literatures have been published. However, the existing slope classification is focused on the slope stability analysis and the reinforcement methods. There is no classification system based on the landslide early-warning system. Different slope deformation evolution processes will directly affect the methods and results of landslide warning. It is of great significance to establish slope classification methods based on the deformation evolution processes and to establish slope classification system focusing on the landslide early-warning. Through the investigation and the analysis, it is pointed out that the deformation evolution process of the slope failure is different, and the induced factors and failure modes are the main factors affecting the deformation evolution process of the slope failure. The deformation evolution characteristics of the rainfall-induced landslide, the earthquake-induced landslide, the artificially induced landslide and the reservoir water-induced landslide were summarized. On this basis, a slope classification method based on the deformation evolution process is proposed. A slope classification system focusing on the landslide warning can be established by using the proposed classification method. The research results can be used as a reference for the slope stability research and the landslide prediction and the warning system. Related Articles | Metrics

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Evaluation on the Stability of Excavated Slope for a Waste Rock Storage Yard Using Strength Reduction Method in Phase 2 Software ZHANG Haoran, ZHANG Jintao, 2025, 39 (2):  272-279.  Abstract ( 181 )   Save Obtaining the useful rock material from a waste rock storage yard that has been operated for an extended period is a crucial method for the utilizing waste resources. The stability of excavated waste rock storage yards is a significant factor to consider. This study focuses on the excavation and the transportation project of a waste rock storage yard in Ningbo City. The stability of conditions of slopes under three different excavation schemes: slope rate 1H:3.0V, slope rate 1H:2.0V, and stepped slope are evaluated. The strength reduction method in Phase2 software is utilized for this assessment. A comparison is conducted between the stability evaluation results of slopes with and without excavation unloading effects. The study demonstrates that the Phase2 software can effectively capture the rebound deformation and the stress redistribution behavior of slopes post-excavation of the waste rock storage yards. The stability factors increase by 10% when disregarding the excavation unloading effect, compared to when accounting for it. Hence, when evaluating the stability of excavation slopes in the waste rock storage yards, failing to consider the excavation unloading effect may result in an overestimation of the safety margins or reserves, potentially posing a risk hazard. Related Articles | Metrics

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Analysis of Double-Row Pile Frame as a Deep Excavation Supporting System Using FLAC-PFC Coupled Method YUAN Qihang, TAN Yihong, 2025, 39 (2):  280-284.  Abstract ( 157 )   Save The double-row pile supporting structure has been widely used in deep excavations, but current theoretical models for the load bearing and the deformation estimations have limitations in addressing the real-world engineering challenges. This study focuses on the double-row pile frame system and combines the FLAC3D and the PFC3D to create a continuous-discrete coupled analytical model. By incorporating both the double-row pile system and the surrounding soil, information is exchanged between the continuous and discrete media using PFC3D wall elements. Numerical simulations are performed to evaluate the stress and deformation characteristics. Results from the literatures show that the proposed method effectively captures the stress and deformation of double-row pile frame system, addressing the issue of rear pile bottom ‘kicking’ often observed with the standard design specifications and following the load transfer path of the system. With the increasing use of innovative double-row pile supporting structures in practical applications, this method proves to be of significant practical value.  Related Articles | Metrics

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Factors Influencing the Axial Capacity of Prestressed Prefabricated Pipe Piles WANG Fei, ZHANG Yan 2025, 39 (2):  285-292.  Abstract ( 141 )   Save Combining the horizontal load tests and the numerical simulation results of prestressed prefabricated pipe piles at a construction site, the working mechanism of the prestressed prefabricated pipe piles under the horizontal load was analyzed. And the influence factors on the lateral load capacity characteristic of the prestressed prefabricated pipe piles were determined and selected. The numerical simulation was carried out specifically using the finite element method to study the influence of these factors on the lateral load capacity. The simulation results show that the hardened thin layer of soil, pile length, pile diameter, vertical load at the pile top, and pile cap at the pile top all affect the magnitude of the pile’s bending moment. Among them, the hardened thin layer will increase the bending moment value at the pile joint, and the pile length will increase the maximum lateral load capacity within a certain length. The increase in the pile diameter will increase the maximum bending moment value under the same horizontal load, and the increase in vertical load at the pile top will reduce the bending moment value at each position along the pile. In order to explore the influence of pile cap to the bending moment of the pile, the anchorage effect of the pile cap is analyzed, negative bending moments are distributed at the top of the pile and the upper side of the pile, and the larger the lateral soil constraint force at the pile cap, the larger the maximum negative bending moment value, and the pile displacement distribution pattern tends to the “retaining wall” pattern.  Related Articles | Metrics

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Vulnerability Assessment of Landslide Hazard Duhe River Basin Using Analytic Hierarchy Process YANG Xin, TIAN Jingjing 2025, 39 (2):  293-299.  Abstract ( 135 )   Save Due to the widespread distribution of metamorphic rocks with high porosity and easy softening when exposed to water along the banks of the Duhe River Basin in northwest Hubei, landslides are easily induced in areas with developed water systems due to factors such as rainfall and human engineering activities. Therefore, guided by the typical metamorphic rock mountain reservoir bank in the Duhe River Basin, a regional landslide vulnerability assessment was performed. The population density, age structure, risk prevention awareness, gender ratio, building type, transportation facility type, and land use type are selected as vulnerability assessment indicators for the study area. By using the Analytic Hierarchy Process to determine the weights of various vulnerability assessment indicators and combining the weights of each indicator with the quantified vulnerability assessment indicators through the construction of a linear weighted model, the vulnerability assessment of landslide disasters in the study area is completed, providing a basic basis and technological support for local disaster prevention and control management. Related Articles | Metrics

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Numerical Analysis of the Anti-Slip Mechanism of H-Type Composite Anti-Sliding Structure WANG Fuqiang, ZHANG Ruidong, SHANGGUAN Jinxing, WANG Dan 2025, 39 (2):  300-304.  Abstract ( 109 )   Save Landslide related hazards occur frequently in our country. The H-type composite anti-sliding structure is one of the common methods for mitigating large landslides. To explore the anti-sliding mechanism and reinforcement effect of H-type composite anti-sliding structure. Now, the FLAC3D program is used to simulate the working state of the landslide rock mass with and without the h-type composite anti-sliding structure. Through the comparative analysis, the results show that after setting the H-type compound anti-sliding structure, the stability and the safety factor of the landslide has been obviously improved. The stability and the safety factor of the landslide increased from 1.02 when not set to 1.31. The shear strain increment of the rock and soil mass along the slip zone is reduced by more than 75% on average, and the plastic deformation zone is reduced by nearly 50%. The average reduction of the horizontal displacement of the rock and soil mass in the sliding body area is more than two-thirds. The strengthening effect of the h-type composite anti-sliding structure is very significant. This shows that the anti-sliding mechanism of the H-type composite anti-sliding structure is that its setting can effectively reduce the shear deformation degree of the rock and soil mass in the sliding plane, reduce the development degree of the plastic deformation zone of the rock and soil mass in sliding zone, and narrow the horizontal displacement of the rock and soil mass in sliding zone. The overall stability of the landslide has been significantly improved. Related Articles | Metrics

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Application of COMSOL in the Development of Soil Cavity under Water Level Fluctuation TANG Yunfeng, LIU Hong, XIANG Xiqiong, WANG Wenjun, LI Linwei 2025, 39 (2):  305-310.  Abstract ( 141 )   Save The karst sinkholes induced by pumping results from several changes in water levels, with each fluctuation reducing the strength of the overburden soil, similar to that of the fatigue effect. Consequently, the influence of fatigue is articulated by delineating the strength attenuation function of the covering soil layer; the water level fluctuation condition is conceptualized as the air pressure fluctuation, and the basic air pressure fluctuation function corresponding to the water level variation is established. The COMSOL solid mechanics and laminar flow modules are utilized in response to the collapse of Yanyu Village in Zhenfeng County, Guizhou Province. The numerical modeling of the fluid-solid coupling in the formation of the soil cavities due to the karst sinkhole induced by the pumping is conducted. The findings indicate that: 1. No plastic zone exists directly above the soil cavity; 2. The orientation of the plastic zone’s development transitions from the failure angle to a vertical alignment; 3. An annular plastic zone manifests on the surface, potentially contributing to the formation of the collapse annular crack; 4. Displacement increases as proximity to the soil hole diminishes. Related Articles | Metrics

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Shear Strength Characteristics and Foundation Bearing Capacity of Coral Sands CHANG Kai, SHI Huanhuan, SUN Liuliu 2025, 39 (2):  310-315.  Abstract ( 214 )   Save Coral sand is widely distributed in the South China Sea, and its mechanical properties are very different from terrigenous sand. To study the effect of average particle size and water content on the shear strength of coral sand, triaxial shear tests were carried out on coral sand samples under different working conditions by using laboratory triaxial tests. On this basis, the influence of the ultimate bearing capacity of foundation on coral sand samples was studied. The test results show that the coral sand exhibits obvious dilatancy and stress softening under low pressure. The peak shear strength and the peak strain increase with the increase of average particle size. With the change of the water content, the cohesion of the soil sample increases first and then decreases and the internal friction angle decreases. Through the analysis and the comparison of the ultimate bearing capacity, the main difference of the bearing capacity coefficient is concentrated in Nγ, in that the coefficient of Terzaghi formula is significantly larger than the other three formulas. The influence of the cohesion on the bearing capacity of Maislav formula is higher than other formulas. Related Articles | Metrics

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Effect of Dry Density on the Coefficient of At-Rest Earth Pressure in Phyllite Residual Soils GONG Huan, XIE Chengpei 2025, 39 (2):  316-320.  Abstract ( 170 )   Save As a special soil, the initial dry density of the phyllite residual soil can have a significant influence on the coefficient of the at-rest earth pressure. This paper focuses on the influence of the initial dry density on the coefficient of the at-rest earth pressure through the K0 consolidation test and the Nuclear Magnetic Resonance (NMR) test. The research results show that the specimen with the smaller initial dry density has a larger pore structure and a greater compressibility. During the loading stage, with the influence of the cementation, the coefficient of at-rest earth pressure first decreases, then increases and then becomes stable. The increases with the increase of initial dry density. In the unloading stage, the at-rest earth pressure coefficient increases with the decrease of vertical stress, and the initial dry density has little influence on the at-rest earth pressure coefficient, which mainly depends on the stress history. Finally, the expression of the at-rest earth pressure coefficient considering the effect of the dry density during the loading and the unloading is analyzed. Related Articles | Metrics

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Study on the Content and Distribution of Unfrozen Water in Frozen Soil Using on Nuclear Magnetic Resonance GE Hongxiao, WU Jiajia, LI Xiaopeng, XIE Haojue 2025, 39 (2):  321-326.  Abstract ( 117 )   Save Frozen soil is a special soil which is different from other general soils. Due to the limitations of the experimental equipment, means and other aspects, current research on the frozen soil is mostly limited to the macro perspective, but the analysis of the content and distribution of the unfrozen water in the frozen soil from the micro perspective is rarely conducted by combining nuclear magnetic resonance technology. In other words, the nuclear magnetic resonance technology is used to test the soil with the constant temperature and the different initial water content as well as the different temperature during freeze-thawing process, and the T2 curve is combined to analyze the occurrence of pores of the unfrozen water from a microscopic perspective. The freezing process includes three stages, namely, the subcooling stage, the rapid decline stage and the stable stage. The influence of the initial water content on the unfrozen water content at the same temperature of the same soil quality in the freeze-thaw cycle is analyzed, and the influence of the initial water content unchanged and the temperature on the unfrozen water content is also analyzed. Then the distribution of the unfrozen water is analyzed according to the change of the content of the unfrozen water, which provides ideas and methods for the later research combining the nuclear magnetic resonance technology with the frozen soils. Related Articles | Metrics

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Experimental Study on Disintegration Characteristics of a Granite Residual Soil ZHOU Baogui, ZHONG Huabin, LIN Kaiyan, YANG Xueqiang, CAI Chifeng 2025, 39 (2):  327-332.  Abstract ( 167 )   Save In the humid and rainy coastal areas of Fujian, the granite residual soil is easy to disintegrate in water, resulting in geological hazards such as landslides, which has a great impact on the slope stability and the road engineering. Therefore, it is necessary to pay close attention to its disintegration characteristics and the occurrence mechanism. In this paper, a granite residual soil in Sanming City, Fujian Province is taken as the research object, and a series of the disintegration test devices are designed. The disintegration tests of the granite residual soil samples under three conditions of the undisturbed soil, the remolded compaction and the cement improvement are performed. The disintegration failure mechanism of the residual soil is explored from the perspective of the soil structure and the composition. The results show that the disintegration process of the granite residual soil samples can be divided into three stages: the surface disintegration stage, the structural failure disintegration stage and the cement dissolution disintegration stage. The disintegration phenomenon of the undisturbed soil sample is obvious, and the disintegration rate is the fastest, followed by the compacted sample, and finally improved sample. The variation of the disintegration rate of the granite residual soil with time is mainly that the disintegration rate of the soil increases first, reaches the peak, and then decreases. The compaction and the cement curing agent can improve the disintegration resistance of the granite residual soil, and the complete disintegration time can be extended to 3~8 times of undisturbed soil. The disintegration failure of the granite residual soil is mainly affected by soil structure, the composition, and the saturation. The combination of the three factors makes the granite residual soil have the characteristics of easy disintegration in water. The research results reveal the disintegration characteristics and the disintegration mechanism of the granite residual soil, which can provide a theoretical basis for the treatment of the granite residual soil in related projects. Related Articles | Metrics

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Analysis of Frost Heaving Deformation Characteristics and Influencing Factors of Railway Subgrade in Seasonal Frozen Regions MA Tao, ZHANG Yonggang, HUANG Shiguang 2025, 39 (2):  333-337.  Abstract ( 189 )   Save In seasonally frozen regions, the frost heave and thaw settlement of high-speed railway embankments play a decisive role in the safety and stability of railways. Using the frost heave deformation monitoring of a specific railway embankment in a seasonally frozen area as the research subject, the deformation monitoring and data analysis were conducted throughout the entire freeze-thaw process. The study obtained the variations in the embankment’s temperature field, freezing depth, and frost heave over time and space. Detailed surveys were also carried out in key areas of frost heave deformation, obtaining the moisture content and fine particle content at different interfaces of the embankment. Through the in-depth analysis of the monitoring data, the study revealed that the primary factors influencing the freeze-thaw deformation of this railway embankment in the seasonally frozen area are water content and fine particle content. It was found that areas with higher water content and greater fine particle content exhibit significantly increased frost heave. Based on the research results, specific recommendations for improving embankment design and reinforcement measures were proposed. The findings of this study provide a scientific basis for the construction and maintenance of high-speed railways in seasonally frozen areas, contributing to enhanced railway safety and stability. Related Articles | Metrics

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Discussion on the Impact of Sonic Tube Installation on the Integrity Testing of Pile by Ultrasonic Transmission Method ZHANG Leibiao, LI Shuchang, MENG Xinqiu 2025, 39 (2):  338-342.  Abstract ( 172 )   Save The integrity of piles is paramount important to the safety of building structures. The ultrasonic transmission method, a well-established technique for assessing pile integrity, involves the use of embedded ultrasonic testing tubes to detect the pile shaft’s condition with a high precision and without causing damage. However, this method’s accuracy is heavily dependent on the quality of the ultrasonic testing tube installation, an aspect that is often overlooked during the construction, potentially compromising the accuracy of the pile integrity assessment. This paper analyzes issues that may affect the ultrasonic transmission method’s effectiveness in pile integrity testing during the design and construction phases. It scrutinizes the verification process of the construction and testing pile lengths at the testing site, identifying reasons for errors or deviations in the installation position of ultrasonic testing tubes during the design and construction. These inaccuracies can significantly impact the reliability of the testing results. By presenting the real-world engineering case studies, the paper highlights the importance of pile length verification during on-site pile testing. It recommends that when discrepancies are found, such as when the tested pile length is shorter than the constructed length, alternative testing methods should be employed for the validation to ensure the scientific rigor and accuracy of the testing process. In conclusion, the paper underscores the necessity for meticulous attention to the installation and verification of ultrasonic testing pipes to ensure reliable pile integrity testing. It stresses the importance of adhering to strict quality control measures during construction to prevent errors that could lead to unreliable test outcomes, ultimately contributing to the overall safety and stability of building structures. Related Articles | Metrics

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Application of Borehole Radar and Sonar Technology in the Investigation of Karst in Underwater Tunnel Projects CHEN Qiang, WANG Qiao, HUANG Zhengyi 2025, 39 (2):  343-348.  Abstract ( 194 )   Save The development of karst features in offshore areas has a significant impact on the construction of underwater tunnels. Therefore, it is critical to determine the distribution limits and morphological characteristics of the karst features before the construction. This article presents the preliminary survey data from a shielded tunneling section of the Dalian Metro Line No. 5 located underwater. By employing the ground penetrating radar (GPR) and the borehole sonar technology for an actual surveying in the well-developed karst area, the study investigates the applications of the borehole radar and the borehole sonar technology in the offshore karst surveys. The results demonstrate the effective application, successfully clarifying the limits of the karst development and the spatial morphological characteristics within the work area, thus obtaining the accurate data related to the degrees of the karst development. The application results from the engineering case history indicate that these two technologies possess high accuracy and reliability in the practical application of the offshore karst engineering surveys. The GPR can determine the depth and undulations of the bedrock surface, the distribution of karst rock cavities, and the development range of the dissolution fractures, while the borehole sonar can analyze the development limits and the spatial morphological characteristics of the karst cavities. The rational and the integrated use of borehole and these two down-the-hole detection methods can effectively clarify the limits and the spatial morphological characteristics of the offshore karst terrain, providing accurate data on the karst development within the impact range of the underwater tunnel design. This information guides the construction of the shielded tunneling machine, ensuring a smooth crossing of the underwater karst area for the metro tunnel project. Related Articles | Metrics