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25 June 2017, Volume 31 Issue 3 Previous Issue    Next Issue

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Effect of Compaction Column in Collapsible Loess Soils in Yan’an MA Haineng1， ZHU Fengjun2 2017, 31 (3):  249-251.  Abstract ( 1040 )   Save The compaction column is a common soil improvement method for the collapsible loess soils and the verification of the soil improvement effect of the compaction columns can improve the understanding of this method. A trail site was selected before the soil improvement project. Laboratory tests, field plate loading tests and the geophysical surface wave methods were used to examine the effect of the trail compaction columns. The soil physical and mechanical properties of before and after the improvement were compared. The results indicate that the collapsibility of the loess soils within the foundation influence zone can be eliminated and the bearing capacity of the composite ground is also satisfactory. Related Articles | Metrics

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Foundation Type Selection and Design of a Commercial Complex LV Hengzhu 2017, 31 (3):  252-255.  Abstract ( 1179 )   Save A foundation type selection comparison was performed during the design for the main structure of a commercial complex. Various factors, such as, structural loading distribution, structural story arrangement, subsurface soil stratigraphy, and physical and mechanical properties of subsurface soils, constructability of different pile types and their cost, are compared. The optimized foundation type, which meets the axial bearing capacity and also is the most cost effective solution, is selected. Related Articles | Metrics

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Application of Grid Formed Soil-Cement Mixing Columns in Both Soil Improvement and Strengthening of the Passive Zone of the Deep Excavation Supporting System of a Municipal Engineering Project YU Dunmeng 2017, 31 (3):  256-258.  Abstract ( 1316 )   Save The subsurface condition of a municipal engineering project consists of thick soft cohesive soil of the first terrace of Yangtze River. Both the deep excavation and the soil improvements are required for the project. A high construction cost and extended construction period were expected if the soil improvement and the deep excavation supporting system were designed and constructed separately. Using the grid formed soilcement mixing columns as the soil improvement and the strengthening of the passive zone of the excavation supporting zone has the advantages in both cost and the construction schedule. Related Articles | Metrics

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Foundation Design of a Heavy Punching and Pressing Equipment for an Automobile Factory WANG Kaili 2017, 31 (3):  259-263.  Abstract ( 1168 )   Save It has a practical importance for the systematic research on the design approaches of the punching and pressing machine foundations due their large earth work quantity, high equipment and installation cost and high requirements on the very small differential settlement as well as the restrictive installation alignment tolerance. This paper presents a case history of design of a heavy punching and pressing machine foundation in Guangzhou. The design details of the machine foundations and ground treatment of the heavy foundation are introduced and the approaches of determining the thickness of the side wall and the bottom slab of the foundation pit are demonstrated. The stress in the side walls are estimated using a special software. The subsurface conditions and the equipment requirement indicated that the prefabricated prestressed reinforced concrete pipe piles are used to support the machine foundation. Related Articles | Metrics

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The Design of the Supporting Structure and the Main Structure of a Metro Station Rail Shaft JIA Zhaoping 2017, 31 (3):  264-268.  Abstract ( 1315 )   Save Rail shaft is a vertical rectangular opening from the ground surface to the metro level and is necessary in some of the metro stations in order to lift the rail tracks to the metro elevation. The rail shaft requires that no internal support can be installed during the metro track installation. Large cantilever arm is required and the stress concentration is also identified in this opening. Different from the supporting structure for the rail shafts for the conventional double story metro stations, the supporting structure for the rail shaft for the single layer has large cantilever arm and higher pore pressure. In order to ensure the safety of the rail shaft and the adjacent structures, the supporting structure utilized double row of HP piles in cased in the castinplace concrete columns based on the subsurface conditions. The stiffener beam was installed at both sides of the opening. Further, the sizes of the structures are determined throughout the three dimensional numerical analysis models since the three dimensional model has a better results in the safety and cost aspects over the two dimensional model. Both the numerical analysis and the construction monitoring results demonstrated that both the supporting structure and the main structure design were successful Related Articles | Metrics

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Application of the Double-Circle Internal Support on a Deep Excavation near the Metro Alignment MO Jinfeng1,2， ZHANG Yu1,2, QIU Jianjin1,2 2017, 31 (3):  269-272.  Abstract ( 1235 )   Save The internal support system has a wide applications in various deep excavation engineering projects. This paper presents the deep excavation support case history of the Shenzhen Headquarter Building of China National Offshore Oil Co. (CNOOC).  The design approaches of deep excavation near the metro alignment are presented. The secant pile combined with the doublecircle internal supporting system is adopted in this project. Using the popular geotechnical commercial software PLAXIS, the mechanical behaviors and the deformation characteristics of the retaining structure and internal supports are thoroughly investigated. In comparison of the computational and the construction monitoring results, it is demonstrated that the design approach of the 'doublecircle internal supporting system' can not only meet the retaining structure safety requirements and cost effectiveness but also satisfy the demanding requirements of the adjacent surrounding structures and facilities. Related Articles | Metrics

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Stability Analysis and Mitigation Measures of the Mined-out Areas beneath the Transformer Substation of a Photovoltaic Power Generation Station CUI Feng 2017, 31 (3):  273-277.  Abstract ( 1280 )   Save With the shortage of land resources, the reuse of lands in the coalmining subsidence areas has increasingly drawn the attention of the public. As a result, the innovative use of these minedout areas, such as, photovoltaic power generation stations, has been proposed. However, the site overall stability of these areas might seriously affects the construction of these facilities, especially, foundations that supporting the transformer substations. Throughout the case study of a specific transformer substation over a minedout area, this paper estimates the loading influence zone above the cavity, the depth of the caving zone and fractured zone. The movement deformation and the stability of site are analyzed and the grouting method treating the cavity areas that can effectively minimize the deformation of the pooling structures are also recommended in the paper. Related Articles | Metrics

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Groundwater and Mud Rush Remediation and Geohazards Prediction in Beilingshan Tunnel Excavation CHEN Lei 2017, 31 (3):  278-281.  Abstract ( 1245 )   Save The groundwater  and mud rush are the frequently encountered geohazards in the excavation of Beilingshan Tunnel. The common reasons that resulting in these geohazards are summarized. Conventional mitigation measures, such as, debris retaining dike, reinforcement by grouting, cavity backfill, small perforated pilot pipe grouting are also introduced in the paper. For the Beilingshan Tunnel project. The site specific geohazards prediction method was proposed for the site geologic condition with rich groundwater and broken rock mass. Related Articles | Metrics

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Numerical Analysis of the Construction Sequence of the Shallow Buried Large Cross Section Tunnel and the Field Monitoring of Ground Movement SUN Xingliang1， CHEN Zhihui2 2017, 31 (3):  282-286.  Abstract ( 1229 )   Save This paper presents a case history of the design and construction of a Luoyang Zhoushan shallow buried large cross section tunnel in loess soil strata. A three dimensional numerical analysis model was established to simulate the soil deformation and the stress in the supporting structures during the tunnel excavation. The results indicate that, the magnitude of the horizontal movement in the soil mass is smaller than the vertical subsidence value. The majority of the soil movements occurred before the supporting structures are engaged. The deformations at the tunnel crest and the ground surface subsidence before the engaging of the supporting structures are 81.5% and 70.5%, respectively. The maximum stress in supporting structure is at the tunnel crest and the stress was rapidly stable after the engaging of the supporting structure. The vertical and horizontal deformation monitoring results are consistent with the predicted values. Related Articles | Metrics

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Application of Slide and FLAC3D in the Stability Analysis of a High Slope near the River Bank XIE Wujun1, WEI Shihao2, YANG Ming1, WANG Lei1 2017, 31 (3):  287-291.  Abstract ( 1335 )   Save The stability aspect of a high slope near the river bank was evaluated with commercial software SLIDE. The slide plane with the minimum factor of safety is located. This slope is also numerically analyzed with the commercial software FLAC3D under the river scoured as well as the heavy precipitation conditions. The effect of the slope deformation on the adjacent building structure is investigated. The deformation influence line of the slope can be plotted based on the displacement vectors and the plastic zones. The slope stability analysis results demonstrate that the most probable sliding plane is within the fill and silty soils. The river scour has impact on the slope movement and the movement increase under the heavy precipitation conditions and might result in the adverse effect on the adjacent building. The site monitoring results are consistent with the analytical results. Related Articles | Metrics

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Shallow Surface Geophysical Exploration Methods and Challenges in the Geotechnical Engineering HU Yijie， HUANG Wen 2017, 31 (3):  292-294.  Abstract ( 974 )   Save This paper discusses the stateoftheart progress of the application of the shallow geophysical exploration methods in the geotechnical engineering. These methods include walking speed strata tomography; resistivity strata tomography and multichannel instant surface wave method. The challenges of the following aspects are discussed:  nonuniqueness of the geophysical exploration methods; back analysis basic assumptions that contradicting with the site conditions, exploration depth versus accuracy and the relationship between the physical properties and the engineering properties. The objective of these discussions is to apply the geophysical method in more and wider engineering practices. Related Articles | Metrics

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State-of-the-Art Progress in the Microscopic Testing Methods and Analysis Methods on Expansive Soils YI Yuan, WANG Weiwei 2017, 31 (3):  295-298.  Abstract ( 999 )   Save Researches on the microscopic aspects of expansive soil are divided into qualitative researches and quantitative researches. In this paper, the microscopic measurement methods of the expansive soil are also divided into the qualitative testing methods and the quantitative testing methods. On the basis of the introduction of the electrical scanning microscope method as well as the other microscopic testing techniques are summarized. The stateoftheart progress of the microscopic study of expansive soils are also discussed in this paper. Finally, various conventional analytical methods are summarized in the paper. The following conclusions are obtained: (1) Although many quantitative testing methods are available, the researches on the microscopic structure of the expansive soil still stays in the qualitative description stage; (2) The depth of the research on the microscopic structure of the expansive is also closely related to the observation method used. Summarized from the observation approaches, it is concluded that a research trend of moving from the individual qualitative study to a combination of qualitative and quantitative approach. The quantitative approach to the soil microscopic structure might be developed in the future; (3) The method of combining with the electrical scanning microscope, mercury intrusion method and fractal theory is an effective method to study the microstructure of the expansive soils. Related Articles | Metrics

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Geological Hazard Risk Assessment Based on the Information Method: A Case Study of Chongyi County of Jiangxi Province LENG Congde 2017, 31 (3):  299-303.  Abstract ( 1661 )   Save In this paper, the geological hazard investigation results of Chongyi County, Jiangxi Province are compiled with Arc GIS based on the information method of Geological Hazard Risk Assessment and the results are presented on a 1:50,000 geological hazard map. The relevance between the various factors and the geological hazard are investigated.  These potential factors that might triggering the geological hazards are: elevation and slope grade of the target object; watershed characteristics; engineering geology, lithology and tectonic structure; locations of residential communities and highways. These factors are grid computed based on the geohazard locations and the geohazard probability distribution and the segmental contribution of each factor and its information value are obtained. The information value of each factor is superimposed and the information distribution map of the target location can be obtained. Based on the probability of information of the each geological hazard point, the potential geohazard within the study area can be divided into high, medium, low, very low levels. The evaluation results and the predicted events are consistent with each other indicating that the proposed method could be useful. Related Articles | Metrics

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Modelling of the Regional Groundwater Flow of in a Potential Disposal-Site of Low and Intermediate Level Radioactive Waste in South China FANG Jiangfeng, LI Xiaoqiang 2017, 31 (3):  304-307.  Abstract ( 1198 )   Save The disposal of the radioactive wastes are the key factor for sustainable development of nuclear energy. The research of groundwater flow field in the has an immediate guidance in the selection of Low and Intermediate Level Radio Active Waste (LILW) disposal site, environmental impact assessment, site arrangement, engineering construction cost and schedule, operation as well as maintenance, etc.. The numerical model was established to simulate the groundwater flow in the potential LILW disposal site. The model verification and calibration were achieved by the analysis of the long term groundwater observation data at the site. The calibrated model was used to groundwater flow field of the site after the filling operation. The results indicate that, after the site earthwork, the low valley areas were filled. The prevailing groundwater flow direction gradually turns from the east to the west with time. The groundwater gradient generally decreases after the earthwork. Related Articles | Metrics

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Influence Factors on the Secondary Consolidation Properties of a Clay Tailings Mine CHEN Feng1, HU Xiaoming1, WU Shangwei2 2017, 31 (3):  308-312.  Abstract ( 1017 )   Save The consolidation related concerns were raised during a height increase of a tailing dam for its capacity expansion. Asa a result, one dimensional consolidation tests were conducted on the cohesive tailing dam materials. The objective of the tests is to investigate various impact of potential influence factors on the secondary consolidation properties of the cohesive tailing dam materials. These factors are: loading ratio, dry unit weight, magnitude of preloading and duration. The results indicate that, the loading ratio has some effect on the coefficient of secondary consolidation when the confining pressure is less than 600 KPa; The coefficient of secondary consolidation does not change when the confining pressure is greater than 600 KPa. The coefficient of secondary consolidation increases with the dry unit weight of the sample, after the preloading, the settlement is significantly less than samples without preloading. The influence of the preloading on the coefficient of the secondary consolidation has effect when the confining pressure is within the range of 100 KPa to 800 KPa. The preloading effect is not obvious when the confining pressure is greater than 800 KPa. The preloading duration has effect on the coefficient of the secondary consolidation when the time is less than a threshold value. After this value, the preloading effect is not obvious. It is also concluded that the relationship between the coefficient of secondary consolidation and the compression index can be statistically represented by a linear regression formula. Related Articles | Metrics

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Role of Tectonic Structure in Bridge Sites Screening for the Jinsha River Crossing at Tiger Leap Gorge WEN Hai1, SUO Peisi1, QIN Yuqiao2 2017, 31 (3):  313-316.  Abstract ( 1215 )   Save Jinsha River Bridge located at the XiangLi highway is across the Tiger Leap Gorge deep canyons. The topography condition and geologic structure as well as the formation lithology are very complicated. In addition, the topography and weathering zone as well as the unloading belts on both sides of the bridge site are unsymmetrically developed with unfavorable geological conditions. The complicated geological conditions result in the extreme difficulties for the bridge site selections. Filtering the key geological factors from various potential affecting factors is critical to the bridge site screening. Results from the comprehensive exploration program indicate that the key factor is the tectonic structure. It is related to the topography, stratigraphy and lithology, adverse geological conditions, geological structures at both banks, weathering zones and unloading belt. Related Articles | Metrics

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Influences of the Slope Surface Strip Load on the Slope Stability HOU Wencui 2017, 31 (3):  317-321.  Abstract ( 1262 )   Save The influence of the slope surface loaded strip load on the slope stability is numerically investigated. The strength reduction method was used in the commercial finite element software PLAXIS. The global factors of safety, location of shape of the potential slip planes under various loading conditions are obtained. The influence of the magnitude as well as the direction of finite strip loads acting at the slope surface on the slope stability are investigated. The results indicate that, when the loading angle is relatively gentle, the role of surface loads can improve the slope stability; when the loading angle increases, the slip direction turns to upward. The shape of the potential slip plane turns from the circular to linear shape when the loading magnitude increases. When the loading angle is relatively small, the area of slope instability zone increases first with the increase of the loading magnitude and then gradually decreases. When the loading angle becomes larger, the area of the potential slope instability zone increase with the loading magnitude and then decreases. As a conclusion, the surface loaded surcharge with a smaller loading angle can actually improves the slope stability. Related Articles | Metrics

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Numerical Analysis of the Soil-Pile Interaction in a Single Pile PAN Chengjin1, PAN Chenggang2 2017, 31 (3):  322-324.  Abstract ( 1028 )   Save The soil-pile interaction of a laterally loaded pile is practically simplified as a plane strain problem. The various loading conditions are numerically simulated with FLAC3D and the results are compared with analytical solutions of active pile and passive pile conditions. The analytical results are summarized in tables that can be potentially used. Related Articles | Metrics

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Analysis of Influence Factors on the Seismic Response of a Tunnel in Fills XIANG Xiaohui 2017, 31 (3):  325-329.  Abstract ( 1064 )   Save The seismic response of a tunnel in fills is numerically simulated. The effect of the seismic loadings in the high earthquake intensity zones on the stress in the tunnel lining structure in fills are modeled under different lining thicknesses, concrete strength values and fill thicknesses. The results indicate that, under the seismic loading, lining and fill thicknesses are the two major factors that are affecting the bending moment and shear force in the tunnel, especially, at the joint of the bottom slab and the mid wall. When the strength of the lining concrete is greater than 30MPa, the influence of the concrete strength on the stress in the tunnel is minimal. Unbalanced fill above the tunnel should be avoided and the horizontal internal support should be added to improve the stress state in the tunnel. Related Articles | Metrics

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Application of PHC Pipe Piles in Liquefied Soils WEN Jiao 2017, 31 (3):  330-334.  Abstract ( 1189 )   Save This paper presents a case history of the application of Prefabricated High strength Concrete (PHC) pipe piles in the improvement of liquefiable soils. The performance of the PHC pipe pile composite ground under the seismic loading is numerically simulated by the commercial software FLAC3D. Results are also compared with castinplace reinforced concrete piles. The results indicate that, the PHC pipe pile can improvement the performance of the composite ground. The degree of liquefaction is 0.20 for the composite ground and 0.48 for the ground without treatment. The dynamic analysis indicate that the PHC pipe pile has a better performance in the liquefiable soils over that of the castinplace reinforced concrete piles. Related Articles | Metrics

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Information Method for the Geohazard Risk Assessment of Yinjiang County of Guizhou Province CAI Qing 2017, 31 (3):  335-340.  Abstract ( 1003 )   Save Geohazards are frequently occurred in the mountain areas of western part of the country. This paper presents the pilot study results on the Yinjiang County of Guizhou Province.  Both the geological hazard inducing factors, such as, ground elevation, grade and direction of the target slope, lithology and the tectonic structures and the environmental hazard inducing factors, such as, annual precipitation and highway engineering, are used in the evaluation by the Arc GIS with information method. The results indicate that areas with high geohazard risk and extremely high geohazard risk in Yinjiang County account for 27.33% and 5.40% of total area, respectively. These areas are mainly distributed in northwestern and southwestern of Yinjiang County. Areas with extremely high geohazard risks are mainly distributed in Eling Town, the south of Banxi Town, Shanshu Village and Zhongba Village. Related Articles | Metrics

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Comparison and Application of Different Shield Segment Analysis Software ZHANG Yixin 2017, 31 (3):  341-344.  Abstract ( 1145 )   Save With the rapid development of urban rail transit, the shielded tunneling technology is widely used in the construction of rail transit. It has become the primary choice of tunnel construction. However, the generally accepted opinion is not identified in selection of an appropriate analysis method as well as the analysis software for the shielded tunnel segment. In this paper, two different shielded segment analysis software for predicting the internal forces in the shielded segment are compared in a practical project. This paper also presents the appropriate recommendations of the analysis in the shielded segment based on the comparison and analysis of the two different software in modeling methods, the load conditions and the results. Related Articles | Metrics

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Optimization Methods for the Tunnel Excavations in Soft Rock with High Geo-stress LEI Wanxiong, LI Qugang 2017, 31 (3):  344-349.  Abstract ( 1092 )   Save During the highway tunnel construction, soft rock tunnels under the condition of high geostresses are prone to having large deformation problems. Huangjiazhai Tunnel of Mazhu Expressway Project was selected as a typical tunnel in the highly geostressed soft rock mass. The construction deformation monitoring data indicate that the deformation rate of the excavated rock mass is fast with a large accumulated total deformation over a long observation period. An obvious creep deformation can be identified form the data. In this paper, the limits of the plastic zone and deformations in the soft rock mass from the numerical analysis results for the four different excavation sequences are presented. These four excavation sequences are: No support and excavation at twosteps; excavation at twosteps with support; excavation around the core support and threestep excavation with support. The results indicate that the initial support can effectively reduce the areas of the plastic zone and minimize the deformation. After the support, the maximum deformation in the surrounding soft rock mass due to the excavation transferred from the top of the arch to the bottom of the tunnel. The maximum deformation as well as the area of the plastic zone in the excavation around the core support are obviously smaller than those in other twostep excavation sequences. When use the threestep exaction with support, the deformation in the surrounding rock mass is the smallest among all other excavation sequences but the subsidence in the top of the arch is the largest. Since horizontal convergence in the excavated tunnel, it is suggested that the threestep excavation with support be used in the Huangjiazhai Tunnel excavation. Related Articles | Metrics

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Stability Evaluation of High Cut Slopes with Coal Lenses in Southern Hunan ZHENG Yichen1, ZHANG Keneng2 2017, 31 (3):  350-355.  Abstract ( 1256 )   Save Geohazards, such as, landslides, have plagued the urban development of Chenzhou City for years. Most of the potentially unstable slopes usually contain coal layers. Soil layers that containing coal lenses have the characteristics of uneven stiffness and compressibility; weak connections between the soil and coal layers; poorly structured; fast weathering after exposed in the ambient environment and fast slaking when adding water; extremely variable engineering properties and prone to significantly reducing the strength when their structure are disturbed. Project experience indicated that the conventional design and construction measures in mitigating the slope related geohazards by applying the current code are not completely satisfactory.  This paper presents a case history of the stability evaluation of a typical high cut slope with coal lenses in Chenzhou City. The progressive failure of a slope is three dimensional numerically investigated by using FLAC3D. The correlations among various construction sequences and the various degrees of stability are investigated. Mitigation measures for the landslides are proposed. The results indicate that the stability of the potential landslide area was improved. Related Articles | Metrics

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Risk Assessment of a High Cut Slope ZHAO Jianxiong 2017, 31 (3):  356-358.  Abstract ( 1026 )   Save Various factors, such as, geological, climate environmental, topographical and design and construction conditions, which might affecting the stability of a high cut slope are analyzed in this paper. The weight of these factors in the cut slope stability are assigned and the risk assessment approach, model and criteria are established based on the global risk evaluation system. This system was applied to the stability assessment of a high cut slope and the results are satisfactory. Related Articles | Metrics

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Statistical Analysis of Mucky Soil Indices of Fuzhou Rail Transit Line No. 2 CHENG Yuanyuan1, FAN Xiufeng1,2， WU Zhenxiang1,2 2017, 31 (3):  359-363.  Abstract ( 1038 )   Save A statistical analysis of mucky soil properties is performed on the laboratory test result of samples from Fuzhou Rail Transit Line No. 2 Project. The variabilities and correlations among various physical and mechanical properties are examined. The correlations between the physical indices and the mechanical properties are established for the preliminary design of future preliminary design of Fuzhou underground engineering projects. The results indicate that the Fuzhou mucky soils have the following characteristics: high moisture content; low dry unit weight; high void ratio; high liquid limit, large compressibility and low shear strength. The variability of the mechanical properties are found to be large and the sample differences should be considered in the future preliminary design. High correlations are found in following parameters: void ratio and moisture content; liquid limit and moisture content; plastic limit and liquid limit; plastic limit and void ratio. Lower correlations can be identified in following parameters: physical properties of moisture content, natural unit weight, void are correlated with mechanical properties: compressibility, compression modulus, shear strength parameters of cohesion and internal friction angle. Related Articles | Metrics

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Combination of Geophysical and Conventional Boring Methods for the Investigation of an Industrial Building over Abandoned Mining Areas in Zhangqiu JIANG Wenfu 2017, 31 (3):  364-368.  Abstract ( 1182 )   Save There are numerous small scale and unregulated abandoned coal and clay mineral mines in Zhangqiu City of Jinan. The backfill shafts were identified within the footprint of the proposed industrial building after the foundation excavation. The geophysical instigation using direct current induced polarization sounding was used to estimate the limits of the abandoned mine areas. The geophysical exploration results were verified by the conventional boring method. Based on the geophysical and geotechnical drilling results, the abandoned mining voids were compaction grout treated. Related Articles | Metrics

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Experimental Study on the Compaction Effect of Hollow Prestressed Reinforced Concrete Square Piles in Soils XI Wenyong1, Qin Xiujuan2, LIN Hongrui1 2017, 31 (3):  369-371.  Abstract ( 1115 )   Save This paper presents a case study of the effect of the compactive efforts in soil induced by hollow prestressed reinforced concrete piles. The physical and mechanical properties of soils and Standard Penetration Test (SPT) numbers before and after the pile installations are compared. The test results indicate that the installation of these piles can effectively eliminate the liquefaction potential and improve the engineering properties of the soil among piles. The strength of the soil and the SPT N values increase and the compressibility decreases after the pile installation. The results also show that more compactive effects can be found in silty and sandy soils than that of clayey soils. The compactive effective is also reversely correlated with the clay content in soils, plastic indices. Related Articles | Metrics

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Application Integrated Geophysical Exploration in Detection of Rock Mass LIU Quanwei 2017, 31 (3):  372-377.  Abstract ( 880 )   Save The geophysical exploration methods are currently applied in the prediction of the geohazards in the tunnel excavations. This paper introduces the application of three different geophysical exploration methods, which are surface high density resistivity method, induced polarization method, and threedimensional seismic method, in the rock mass characterization in front of the tunnel excavation area. The integrity of the surrounding rock mass and the groundwater fracture zones and be reasonably identified and the remediation measures such as, grouting and supporting can be applied. The surrounding rock mass features predicted by the integrated geophysical methods were verified by the subsequent tunnel excavation. These methods are proven to be a reliable way to reveal the source of potential hazard and can ensure the construction safety. Related Articles | Metrics

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Geohazards Advanced Prediction System in TBM Excavation of Neelum-Jhelum Hydroelectricity Project in Pakistan XIONG Haosen， ZHU Bin 2017, 31 (3):  378-382.  Abstract ( 1364 )   Save The geohazards, such as, groundwater rush, collapse and excessive deformation, are frequently encountered in the tunnel excavation by Tunnel Boring Machine (TBM). These hazards might result in jam, burry and even the completely loss of TBM equipment. In order to minimize the potential risks, an advanced prediction system can be introduced in the TBM excavation to predict these adverse geological conditions and to prepare the mitigation measures. As the first application of TBM excavated tunnel in Pakistan, the tunnel for the NeelumJhelum hydroelectricity project is located at southern side of Himalaya Mountains and no previous long distance tunnel was constructed. In order to control the potential risks and geohazards, three independent advanced prediction systems, namely, Integrated Seismic Imaging System (ISIS), Tunnel Seismic Tomography (TST) and a conventional advanced prediction system, were installed in the tunnel excavation. The results demonstrated that these systems provided a large amount of useful information regarding the rock mass conditions and facilitated the tunnel excavation. Related Articles | Metrics