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20 February 2018, Volume 32 Issue 1 Previous Issue    Next Issue

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Secant Pile Slurry Wall Construction in Soft Soils with Stone Fills JIAN Wancheng1, ZHOU Xueliang1, GONG Lei2, XI Yongjun2 2018, 32 (1):  1-3.  Abstract ( 1636 )   Save This paper presents a case study of a secant pile slurry wall construction for the deep excavation of Shekou Cruise Center in Shenzhen. In the thick stone fills in near shore soft cohesive layers, the slurry walls are usually installed by using high or regular pressure jet grouts and secant piles. Compared with different wall types, it is concluded that the combination of castinplace lean concrete pile with the reinforced concrete piles could meet the design requirements. This paper presents the unique construction procedure in the subsurface conditions of thick stone fills and the brackish groundwater. The results indicate that the second pile is a reliable and efficient slurry wall type. Related Articles | Metrics

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Soil Mixing Optimization Design of Utility Culverts in Soft Soils ZHOU Heng1, FAN Xiang2, DU Chao2, XIE Dehu3, CHE Hongbo3 2018, 32 (1):  4-9.  Abstract ( 1323 )   Save The Pukou Central Business District (CBD) is in the soft soil zone Yangtze River of alluvium zone. The soilcement mixing column is the major soil improvement method for the combined utility culverts. A doublecell culvert cross section was used in area underneath Linjiang Road. The soilcement mixing column had a diameter of 500 mm, spacing in the longitudinal direction was 1.5 meters and 1.2 meters in the transverse direction. The performance of the soil mixing columns with various column stiffness, spacing and column length were parametric studied through the threedimensional finite element analysis. The soil improvement design for the utility culverts was able to be optimized from these numerical investigations. Related Articles | Metrics

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An Improved Design Method for Deep Excavation in Soft Soil by Steep Pipe Raking Supports XIAO Rongjun 2018, 32 (1):  10-12.  Abstract ( 1091 )   Save In the deep excavations with very large area, if the depth of excavation is not excessive, the common excavation support method is the raking support utilizing the bottom structure as supporting points. An improved supporting method by using the additional platform without compromise the construction schedule is proposed to resist the axial force of the raking supports. The improved supporting method was verified by the analytical design method for the axial force, commercial excavation design software, and the monitoring results. It is concluded that the stress and strain in the pile are similar with three different method. Related Articles | Metrics

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Slope Stability Options for a Waste Soil Site YAN Yuqi， HOU Longqing 2018, 32 (1):  13-16.  Abstract ( 882 )   Save The waste soil sites have a large amount of new nonhomogeneous uncompact soil fills. These soils have the characteristics of low bearing capacity, prone to collapse and sliding. With the increase of the human activities, the appropriate sites for the engineering projects in the urban area becomes more and more demanding. The utilization of the waste soil sites is a viable solution. The slope stability measures that are feasible for the waste soil sites are discussed in the paper. Related Articles | Metrics

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Supporting Design of Deep Excavation Near an Existing Basement PENG Ying 2018, 32 (1):  17-19.  Abstract ( 1046 )   Save This paper presents a case history of the supporting design of a deep excavation with a distance of 20.6 meters to the existing basement. The net spacing between the piles of two adjacent excavations was only 13.2 meters and the ground anchor option was not feasible. The improved method value engineered the original design of double pile option with the combination of soil unloading and sloping. The improved method was proved to be a safe and costeffective method. Related Articles | Metrics

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Piping Remediation and Prevention in Dongting Lake Area LIU Chuang, WU Nengjie, ZHANG Yihua, ZHU Ping， HE Kechao 2018, 32 (1):  20-22.  Abstract ( 872 )   Save Geohazard occurrence frequency increases with the social economic development and engineering activities. Geohazards could seriously affect the properties, human safety as well as social sustainable development. This paper presents the 1:50,000 scale geological investigation results of 54 piping locations in Nanxian and Ziyang, Yiyang City. Soil samples were collected from the two piping locations with each at Nanxian and Ziyang and laboratory tested. It is concluded that the piping preventive measures should be within 15H away from the toe for levees in Dongting area. These investigation results can provide information in minimizing the piping hazards in Dongting area. Related Articles | Metrics

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Analysis of Debris Flow Hazard Remediation Methods of Xueshan River Basin JIANG Xuhui, LI Xieneng, ZHOU Lianyi 2018, 32 (1):  23-26.  Abstract ( 780 )   Save Debris flow hazards are frequently occurred in Xueshan River Basin recently. Remediation measures were applied at various locations in different time. A comprehensive analysis of the results of existing debris mitigation projects can provide indepth understanding for the future engineering applications. Xueshan River is in Yangbi County of Dali City at the west side of Diancang Mountain. The tectonic structure of the area is complicated with broken rock mass and it also has a large amount of colluvium material derived from the collapse of the rock mass due to the intense precipitations in a short period time. The authors conducted a geological investigation in the Xueshan River watershed and evaluated the results of various debris flow mitigation measures. It is concluded that the mitigation method with the idea of cutoff and stabilizing are not very effective. The more effective mitigation measures should have an idea of mainly diversion plus some of engineering stabilization, bioengineering as well as monitoring measures. Related Articles | Metrics

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Environmental Impact Analysis of Jinkou Landfill Site in Wuhan ZHU Fanji1, SHU Wutang2, LIU Youxiang3, DENG Qingjun1 2018, 32 (1):  27-30.  Abstract ( 1283 )   Save Landfill is a major municipal trash treatment measure but the adverse impact on the adjacent environment is increasingly obvious. This paper presents the study of Jinkou landfill on the adjacent environment. The chemical components and other indices of the landfill leachate on the adjacent groundwater and soil were investigated. Throughout the monitoring results of soil and groundwater, it is concluded that the perched water at the upper and middle layer was moderately contaminated and soil and ambient atmosphere were relatively unaffected. The landfill leached liquid with heavily contaminated is a major impact to the adjacent environment and it should be properly treated for the environmental improvement.  Related Articles | Metrics

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Quality Assurance and Controlling Factors for the Construction of High Fills JIN Chun1, XU Bangshu1, YANG Laihua2, LIAN Yanwu2 2018, 32 (1):  31-34.  Abstract ( 842 )   Save The quality assurance and quality control of high fills are very important for the construction of airport in mountain areas. In a case study, the correlations between various quality control criteria and index properties, such as, dry density, degree of compaction and porosity, are discussed and the optimum quality control criteria are recommended. In the east side of the project area where the fill thickness exceeded 100 meters, the controlling factors were: degree of compaction, maximum loose layer thickness, and tolerable leveling fills. The trial fill blocks were tested by using impact and vibratory compaction methods respectively. The thickness of the fills, number of compactions and optimum moisture contents were obtained through the trial test blocks. Related Articles | Metrics

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Spectral Characteristics and Comparative Analysis Vibrations of the Transition Zone of High-Speed Rail Embankment and Viaduct DING Kunpeng 2018, 32 (1):  35-41.  Abstract ( 1190 )   Save While the highspeed rail provides a new and efficient travel experience to the public, the impact of the vibrations induced by the operational highspeed rail on the adjacent residents and buildings require detailed investigation. The vibration spectrum and dissipation characteristics in the soft soils underneath the rail alignment is critical to the evaluation of the adjacent environmental quality. In this paper, the highspeed rail segment between Qingsheng station and Shiziyang tunnel in GuangzhouShenzhen passenger rail line is used for the vibration study, the vibrations in the embankment zone, embankment and viaduct transition zone and viaduct zone, especially, the vibration characteristics of the transition zone which received less attention previously, were field monitored and studied. The time and spectrum distribution characteristics, intensity as well as dissipations are statistically analyzed. The dissipation formula of vibration in the transition zone was developed. The time and frequency differences among the vibrations in embankment zone, transition zone and viaduct zone are discussed and the possible factor that could result in these differences are explored. \= 〖WTHZ〗Key words\ 〖WTBZ〗 〖WT〗〖ST〗〖HT〗 Related Articles | Metrics

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Numerical Analysis of the Effect of a Pipe Jacking Closely Above an Active Subway Tunnel CAI Wulin 2018, 32 (1):  42-45.  Abstract ( 1091 )   Save With the rapid development of urban rail transit, the pipe jacking over the active subway tunnel becomes more and more frequently, especially, within the densely populated urban area with many subway tunnels. Comparing with other construction methods, the pipe jacking method over the active subway tunnel is more cost effective. However, the soil disturbance during the jacking might have an adverse effect on the adjacent tunnel. Both the subsidence and the heave of the ground surface, as well as the “float” of the subway tunnel under the pipe jacking area should be well monitored and controlled. This paper presents the threedimensional numerical analysis results of a pipe jacking installation over Subway Line No. 1 in Suzhou City using commercial finite element software ABAQUS. The deformation of the subway tunnel during the jacking operation are simulated and simulation results are compared with field monitoring results. Related Articles | Metrics

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Some Considerations of Applying Digital Images in the Expansive Soil Crack Analyses ZENG Xianyun1, LIU Guanshi2, CHEN Yonggui1， CHEN Ruyi3 2018, 32 (1):  46-49.  Abstract ( 898 )   Save The photographic image is a new method for  study  soil crack. There are many factors that affect the quantitative analysis of crack characteristics in the data acquisition and processing of the digital image. Common problems encountered in the expansive soil analysis are explored. The effect of factors, such as, light source, resolution of the image and threshold values in the digital processing, on the digital processing are discussed and improving suggestions are proposed in the paper. Related Articles | Metrics

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Rheological Properties of the Compacted Red Clay in Kunming Region SUN Xiwang1, LI Liangji2, YANG Guoyue2, XU Yunlong2 2018, 32 (1):  50-54.  Abstract ( 1023 )   Save The engineering characteristics of red clay soils vary significantly in different regions. This paper presents a case history of the rheological properties of the compacted Red Clay under high fill in Kunming area. The longterm rheological tests were performed on samples with different degrees of compaction and different moisture contents. The following conclusions can be obtained from the test results: when the degrees of compaction are greater than 92%, the creep properties are not affected by the degrees of compaction. Under the same degree of compaction, when the moisture content is lower than 21.26%, the creep decreases with the increase of moisture content. The secondary consolidation coefficient is introduced in the study to further characterize the effect of moisture content on the rheological properties of the Red Clay. Under the same degree of compaction, a moisture content for the minimum settlement exists between 15.83% and 21.26%. A post construction settlement analysis model was developed considering the creep effect. It was found that the moisture content for the minimum post construction was 18.33%, whereas, the optimum moisture content for the compaction was 20.77%. Related Articles | Metrics

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Finite Element Analysis of the Behavior of the Upper Portion of Pile in the SelfBalanced Loading Test LIU Yuan, JIANG Yuchuan 2018, 32 (1):  55-58.  Abstract ( 931 )   Save The load transfer mechanism in the upper portion of the pile during the load tests is analyzed in this paper. A threedimensional numerical analysis model is developed by considering the pilesoil interface properties. The actual load transfer, vertical displacement and stress in the upper portion of the tested pile are obtained. The effect of pile stiffness on the deflection of the pile section and the side friction are also investigated. Related Articles | Metrics

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Rigid-Flexible Composite Column and Axial Capacity Estimation Method DONG Kaipo 2018, 32 (1):  59-63.  Abstract ( 868 )   Save The rigidflexible composite column is a soft soil improvement method by inserting a rigid column into the center of the flexible column. The rigidflexible composite columns could be the same length or different lengths for different subsurface soil conditions. For two or more layers of subsurface soil strata, the flexible columns could be placed at shallow layer and the rigid columns could be installed in the deeper layer. Different column lengths could be used for different subsurface soil conditions for the total and differential settlement control and axial capacity improvement. This composite column could effective minimize the “bump” at the bridge approaches. Based on load transfer mechanism study, an improved Berezantzev Method for axial capacity estimation method is proposed. Using the pile foundation code for buildings, this new method considers the roadway surcharge load and effective stress induced by the side frictions for the prediction of the tip resistance and side frictions. Related Articles | Metrics

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Effect of NaCl Solution on Shrinkage Properties of Kaolin Soil HE Jintang1， YAN Rongtao1， NIU Geng1， ZHANG Min1， YU Mingbo2 2018, 32 (1):  64-68.  Abstract ( 893 )   Save The effect of the solution concentration on the shrinkage properties of the Kaolin soils are investigated in this paper. The shrinkage limit of a total of six (6) series of samples saturated with NaCl solution of various concentrations were laboratory tested for the shrinkage curves. The salt concentrations in the soil pores would increase with the decrease of the moisture contents. The threedimensional graphs among the moisture content, solution concentration in soil and void ration were plotted by the TableCurve 3D software. A function with three variables were statistically developed through the curve fitting. By using his function, the relationship between the void ratio and the moisture content under different salt concentrations were obtained and the sample shrinkage characteristics are able to be analyzed. The results indicate that, with the increase of the salt concentration in the soil, the shrinkage range increases. The coefficient of the shrinkage, axial, radial and volume strains are also increasing with the increase of the salt concentrations. However, the effect of salt concentration on the Kaolin soil is limited. Related Articles | Metrics

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Analysis of Deformation-Failure Mechanism of Clastic Rock Slopes in Tropical Humid Environments HE Feng1， XIANG Rui2 2018, 32 (1):  69-74.  Abstract ( 1173 )   Save The frequent occurred landslides in the clastic rock is a common geohazard in Guangxi’s tropical humid environment. Based on the site geological investigation and geotechnical exploration results, a longterm slope deformation monitoring was developed by installing the inclinometers, magnetic extensometers and groundwater monitoring device at various locations of a sliding slope. The sliding surface was identified throughout the deformation of the inclinometers. The deformationfailure mechanism was able to be developed. It is recognized that the landslide in the clastic rock slopes is strongly affected by the heavy precipitation and human activities. The tectonic structure of the slope is also contributed to the landslide hazards. Related Articles | Metrics

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State-of-the-Art Review of Moisture and Solution Transporting in Red Clay CHENG Guodeng1， JIANG Yi2 2018, 32 (1):  74-77.  Abstract ( 1136 )   Save The transporting of the moisture and solute in the soil has received an increasing research attention since the increasing water and soil pollution concerns. As a widely distributed regional special soil in southern China, researches on the moisture and solute transporting in the Red Clay have the significant meaning. This paper presents the stateoftheart review of the moisture and solute transporting in soils. Researches results on the Red Clay soils are also reviewed. Related Articles | Metrics

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Laboratory Investigations of Guilin Red Clay Improved with Sand and Fly-ash ZHU Shouzeng1，2， LIU Huiqiang1，2， LIANG Puyuan2 2018, 32 (1):  78-80.  Abstract ( 1071 )   Save Both physical properties and mineral composition of Guilin red clays are unique. To investigation the effect of the sand and flayash mixing on the Guilin red clay improvement, a series of laboratory tests, such as Atterberg limits, direct shear tests and Proctor tests, were performed on soils mixed with various amounts of sand and flyashes. It is concluded that the optimum sand content is 20% and flyash content is 10%. Related Articles | Metrics

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Nonlinear ElastoPlastic Analysis of a Large Span Columnless Subway Station MA Shuwei 2018, 32 (1):  81-83.  Abstract ( 922 )   Save Recently, the columnless subway stations become more and more popular with the development of urban rail transit system. Since the width of the platform in the subway station could be more than 11 meters wide, the crosssection type and stress distributions in the structures need to be investigated. The nonlinear elastoplastic finite element analysis studies were performed for the strcture elements of the subway station. The plastic and cracking zones were identified for the appropriately arranging the steel reinforce bars. Based on the analysis results, the uplift piles were installed at the bottom of the platform and arches were placed at the roof of the subway station. Related Articles | Metrics

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Karst Terrain Investigation and Groundwater Inflow Prediction in Zijingshan Tunnel Excavation LI Fanghua 2018, 32 (1):  84-87.  Abstract ( 1472 )   Save This paper presents the comprehensive investigation using conventional test borings, geophysical exploration results of the quality of the rock mass with various degrees of weathering, broken zones, potential karst cavity location & filling materials and groundwater inflow location and quantity predictions in the Zijingshan Tunnel in DaqingGuangzhou Expressway Project. The geophysical exploration method used in the investigations are: remote sensing, ground acoustic frequency electric magnetic waves as well as shallow seismic reflection wave methods. The maximum and normal amounts of groundwater inflow were predicted using different modelling methods. The monitoring results indicated that the different with the predicted way only 19.4%.    Related Articles | Metrics

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3D Modeling of the Seismic Wave CT Karst Rock CharacteristicsUsing Voxler Platform LI Zuneng 2018, 32 (1):  88-92.  Abstract ( 998 )   Save The seismic wave CT exploration results on the karst terrain investigation were processed by using Voxler digital threedimensional visualization platform. Some graphical processes such as slicing, volume and surface rendering were applied to the 3D numerical modeling of the seismic wave velocity. Throughout analyzing of the seismic wave velocities, the quality of rock mass in the surveyed field was characterized and boundaries with strong Karst development zones were developed. The spatial distributions of the karstic rock zones were also modeled so that the spatial interpretationsof seismic wave CT data were improved by the visualization software. Related Articles | Metrics

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Parameter Optimization of an Long Diagonal Cutting in the Tunnel Blasting Excavation ZHAI Weijie1， ZHAO Qidalatu2， WU jie2， CHENG Kang1， MA Yongbin1 2018, 32 (1):  93-94.  Abstract ( 868 )   Save The long diagonal cutting has been widely used in the tunnel blasting excavations. The angle and length are the key parameters for a successful excavation. Throughout computer simulations and field tests, the optimized cutting angle of 70 degrees was obtained and it was verified to be an appropriate cutting parameter. Related Articles | Metrics

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Effects of Sampling Methods on the Shear Strength of Ningming Expansive Soils HUANG Xuanzhang, CHEN Yongjian， WEN Songsong 2018, 32 (1):  95-98.  Abstract ( 807 )   Save The effect of sample preparation methods on the shear strength of Ningming expansive soils is investigated by using direct shear tests. Three different sample preparation methods were explored: fresh water prepared submerged in salt water; salt water prepared sample submerged in salt water and fresh water prepared sample leached by salt water. The effect of different concentration of the salt water are also investigated. The results indicate that, the concentration of fluid in the soil as well as the sample preparation methods have effects on the shear strength. With the increase of the salt concentration, the cohesion as well as internal friction angle decrease in samples prepared by all three different methods. The shear strength values are different in samples prepared with different methods. Sample prepared by the salt water leaching has the largest influence on the shear strength. Related Articles | Metrics

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Application of High Density Resistivity Method in the Bauxite Deposit in the Goaf Area ZHANG Kaiwei1, YUAN Pengju1， MA Qingzhou1， DENG Zongren2 2018, 32 (1):  99-102.  Abstract ( 990 )   Save This paper presents a case history of the application of the highdensityresistivity method to the exploration of Shanxi bauxite deposit in the goaf area. The vertical and horizontal limits of the bauxite mine were determined from back analysis of the abnormal effect of the high and low resistance values. The deposit limits determined by the highdensity resistivity method were also verified by the exploratory borings. The results indicate that the geophysical exploration method is a reliable method in the exploring the bauxite mine deposit in the goaf area. Related Articles | Metrics

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Self-balanced Load Test of Deeply Embedded Tensile Piles ZHU Jianmin， JIN Pengliu， XIE Lifei 2018, 32 (1):  103-105.  Abstract ( 1203 )   Save The head of the uplift piles in the deep excavation of the T2 Shenzhen Qianhai integrated transportation hub are embedded 29 meters below the ground. The tensile capacity of these piles was tested by using a selfbalanced load testing device. The strain gages were installed at the reinforcement bars near the pile head so that effect of the overburden soil above pile on the uplifting capacity could be eliminated. A total of six piles were load tested and the Q-s curves (upliftingdeformation curves) had a shape of gradual change and met the design requirement. It is concluded that the selfbalanced load test has the advantage of simple equipment, no reactions at the ground surface and short testing duration. Related Articles | Metrics

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Study of Optimized Mixing Ratio of High Pressure Prefabricated Cement-Soil Columns GUO Yukui1， CHEN Dafen2， DAI Ye3， FENG Lei2 2018, 32 (1):  106-110.  Abstract ( 1114 )   Save The development of a new prefabricated high pressure formed cement mixing soil column equipment is introduced in this paper. Under a pressure of 25 MPa, the relationship between the cement ratios and the compressive strength of prefabricated cementsoil columns are investigated. The cementsoil block samples with different mixing ratios and the unconfined compressive strength correlations are obtained throughout the regression analysis. The amount of cement, lime and water in the prefabricated high pressure formed cementsoil columns are optimized and the appropriate cementwater ratio range is between 0.4 and 0.7. Related Articles | Metrics