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20 August 2012, Volume 26 Issue 4 Previous Issue    Next Issue

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Metro Construction Using Shielded Tunneling in Unweathered Granite Boulder Zones HUANG Liping 2012, 26 (4):  1-4.  Abstract ( 2510 )   Save This case history introduces the typical construction practice of shielded tunneling in Shenzhen. The construction means and methods of shielded tunneling in unweathered boulder zones of granite formations are discussed. Related Articles | Metrics

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Field Monitoring of a Deep Excavation Supporting Program NIU Muwei, JING Lijun, TONG Xing 2012, 26 (4):  5-8.  Abstract ( 2224 )   Save This paper presents field observation results of a deep excavation for construction of a metro in Beijing. During construction, the horizontal displacement of the supporting structure, the stress in the steel strut, and the earth pressures on the soldier piles are monitored. From the monitoring results, it is concluded that the horizontal displacements of the soldier piles are very small; the stress in the steel strut is much smaller than the threshold stress of 80% of yield stress of steel. Both the stresses and the earth pressures acting on the soldier piles are within the safety limits. These results could serve as a reference for the design and construction of similar deep excavation supports. Related Articles | Metrics

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Vacuum Combined with Water Covered Preloading for Soft Soil Improvements for Residential Buildings GONG Lifei，ZHU Fangfang，ZHANG Hong, CHEN Wanzhao 2012, 26 (4):  9-11.  Abstract ( 3117 )   Save It is a common practice for soil improvement methods in residential areas to strengthen only soils under the buildings. Therefore, differential settlement after construction might occur and even result in the cracking and/or tilting of buildings. This paper presents the results of a Vacuum Combined with Water Covered Preloading method for the entire site of a proposed residential development. Both theoretical and practical aspects of this technique are discussed in the paper. It is concluded that this method is successful in minimizing potential differential settlement. Related Articles | Metrics

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Design and Construction of a Large Deep Excavation Support in Peat Soils in Kunming WANG Congming1, XU Yangqing2 2012, 26 (4):  12-15.  Abstract ( 2599 )   Save The characteristics and challenges of the design and construction of a deep excavation supporting system in peat soils in Kunming are introduced in this paper. Using field monitoring data, it is concluded that the circular internal supporting system has advantages over other shoring methods for deep excavations in peat soils. Related Articles | Metrics

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Improvement of Railway Tracks for the Underpass Tunnel HOU Xingping, WANG Chunlan 2012, 26 (4):  16-17.  Abstract ( 2110 )   Save This paper presents a cost effective railway track improvement technique prior to the construction of an underpass tunnel. By utilizing this track reinforcement technique, safe operation of the railway is ensured during tunnel construction. Related Articles | Metrics

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Study of the Instability of Expansive Soil Slopes and Their Improvement Techniques ZHOU Dali, YANG Shuhua, YAO Shengpeng 2012, 26 (4):  18-20.  Abstract ( 2678 )   Save This case history presents the treatment of expansive soil slope instability hazards near a bridge construction site. From the soil stratigraphy within the affected slopes, physical and mechanical properties of various soil strata as well as the hydrogeological conditions, it is identified that the initiation and the development of the fissures are the main factors that cause adverse movement of the slope in expansive soils.  The limits of the weak zone can be estimated from the locations of the cracks near the bridge piers and the transverse tension cracks near the abutment pavement. The stability of the affected zones is evaluated by the software GEOSLOPE. Based on the failed slopes at the bridge site, the shear strength parameters are backanalyzed using the limit equilibrium theory. The rehabilitation program includes antislope piers with a rectangular crosssection, local unloading, as well surface drainage improvements. Related Articles | Metrics

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Application of  Geogrid Material in Slope Reinforcements YU Yuan, TAN Jinghe 2012, 26 (4):  21-23.  Abstract ( 2088 )   Save Retaining walls constructed with geogrid are a new and flexible retaining structure system. They result in fast construction, a cost effective solution, and strong adaptability to different foundation types. Aspects of  design and construction of this wall type are briefly introduced in this paper and selected case histories are provided. Compared with the conventional retaining wall types , the geogrid reinforced retaining walls can reduce the cost of the initial investment by one quarter. Related Articles | Metrics

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Techniques Improving Soft Soils at Greater Depths ZHANG Peng, XIONG Xi, CAO Hui 2012, 26 (4):  24-26.  Abstract ( 2167 )   Save Two sections of typical geotechnical instrumentation monitoring results for vacuum preloading improvements of thick soft soils at an expressway construction site in Guangdong are presented in this paper. The monitoring data indicate that the patterns of the drainage path have a large effect on the improvement results of soft soils at deep depths. Further studies demonstrate that the degree of vacuum has a different transfer pattern in various vertical prefabricated drains. A new vertical drain pattern that can effectively reduce the vacuum loss is proposed. Better soil improvement results for soft soils at greater depths can therefore be achieved. Related Articles | Metrics

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The Application of Bell Ended Piers for Transmission Lines in the Gobi Desert ZHAO Huaiyu1，LI Zhanling1， WEI Penghui2 2012, 26 (4):  27-30.  Abstract ( 2277 )   Save This paper recommends an uplift capacity formula for bell ended piers in cobblegravel sized materials in the Gobi Desert. The uplift capacity is established based on the influence zone of the soil shear failure plane parameter, n; and the influence zone of the uplift shear failure mode. The axial compressive capacity of the bell ended pier is also recommended. The foundation dimensions of 800 kV transmission lines are optimized using a generic algorithm. The results indicate that an overall cost saving of 25% can be achieved when compared to the recommended method with the code specified formula (n=1.5). Related Articles | Metrics

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Collapse and Remediation of a Shallow Buried Tunnel during Construction XU Qinghui 2012, 26 (4):  31-33.  Abstract ( 2876 )   Save Potential for collapse, both small and large, are inevitable in urban metro construction. However, the consequence of metro collapse in urban areas could be far greater than the consequence of tunnel collapse in remote areas and might have a significant adverse effect of on urban residents. Therefore, fast and effective remediation after an accident should focus on resuming the traffic and ensuring the safety of the adjacent structures and facilities. If the collapse resulted from water leakage, the water removal measures should be the first priority over other remediation measures. Fill materials over the collapsed zone should be lightweight and high strength. Overall monitoring and survey measures should be accurate and on time so that the feedback from the site can be provided to facilitate the decision make process. Related Articles | Metrics

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Construction Techniques in the Transitional Zones in ShenDan Passenger Rail Lines CHEN Yanru, YANG Bo 2012, 26 (4):  34-35.  Abstract ( 2517 )   Save This paper introduces structural characteristics and construction techniques of the subgrade transition zones in the ShenDan passenger rail lines. These subgrade transition zones include: embankmentbridge; embankmentculvert; fill and cutembankment. The paper recommends key construction techniques and differential settlement control criteria. Related Articles | Metrics

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Tunnel Excavations in Expansive Shale Rock Mass Using TBM WANG Yanxia, XING Fengmao， ZHANG Yueling 2012, 26 (4):  36-39.  Abstract ( 2365 )   Save Expansive shale rock masses have low strength, high weathering, and low resistance to the water and moisture. When the tunnel is excavated in this rock mass using a Tunnel Boring Machine (TBM), large deformations will occur in the tunnel cross sections. In addition, if the humidity in the excavation changes rapidly, expansion and contraction will occur in the expansive shale. Along the proposed tunnel excavation alignment, the rock mass is severely folded due to rapid change of dip directions. The broken zones along the daylighting joint direction are very well developed. The jointed rock mass is usually discontinuous. When a tunnel is excavated using TBM, various collapses might occur at the working surface due to stress relief and re-distribution. In order to reduce this disturbance to the rock mass, the excavation technique should be: "Three Lows and One Continuous": Low Thrust Force, Low Drill Bit Rotation; Low Penetration and Quick Continuous Forward. The side blade of the TBM should be adjusted so that a larger tunnel cross section can be created. The exposed rock mass needs to be quickly sealed off and the water consumption during the penetration should be strictly controlled. During construction, the TBM excavation guidance documents were improved and modified, i. e., longitudinal and radial pilot grouting holes were created at the proposed shielded zones so that the rock mass stability could be improved by chemical grouting. These techniques were successfully utilized in argillaceous soft rock masses with a total linear excavated length of 13,532 meters. This length consists of 67% of the total tunnel excavated in the project. Related Articles | Metrics

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Application of Soldier Pile with Prestressed Ground Anchors in the Landslide Remediation FENG Jun 2012, 26 (4):  40-43.  Abstract ( 2177 )   Save This case history presents the characteristics and the applications of a soldier pile with a prestressed ground anchor system in landslide remediation. The advantages of this system have been verified in the stressstrain behavior in the soldier pile, system design principles and the construction. The field monitoring results are also presented in this paper. Related Articles | Metrics

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Soil Parameter Sensitivity Analysis Soil Slopes Using Strength Reduction Method XU Yanbing1, WANG Xinzhi2 2012, 26 (4):  44-47.  Abstract ( 2587 )   Save The factor of safety of soil slopes is studied in finite difference analysis (FDA) based on the strength reduction approach. This paper introduces a new finite difference method and a strength reduction approach in a soil slope stability analyses. In a verification analysis, the effect of the dilatant angle, cohesion and the internal friction angle of soils on the stability of the soil slopes are studied. The results indicate that the factor of safety increases with the increase of dilatant angle, cohesion and internal friction angle, respectively. Related Articles | Metrics

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Strength Reduction Method in the FEA of Slope Stability Using ANSYS BAO Lei1, LEI Jinsheng1, JIN Zhengtao1，QIN Yanfu2 2012, 26 (4):  48-51.  Abstract ( 3070 )   Save The strength reduction method is used in the finite element analysis (FEA) of a slope stability problem. The basic principles of the strength reduction method, physical meaning of the factor of safety, yielding criteria, selection of flow rules as well as the criteria for the slope failure are introduced in this paper. As an example of applying this method, the soil strength parameters used in the FEA for the slope stability problem are progressively reduced until the FEA cannot converge. The strength reduction factor that caused the divergence of the FEA is the factor of safety of the slope analysis. When a slope reaches equilibrium, the plastic strain, which is initialized at the toe of the slope, approaches the top of the slope. The reduction factor used in the analysis when a continuous plastic zone is developed can be treated as the factor of safety. Related Articles | Metrics

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Uplift Capacity of the Underream Ended Anchors Formed by Jet Grout GUO Wenlong，LI Chongyang，GONG Xing，LI Jin， XIONG Zhuang 2012, 26 (4):  52-55.  Abstract ( 2119 )   Save The uplift capacity of the underream ended anchors formed by jet grout is simulated by FLAC3D.  The Q~S curve is developed from the parametric study.  Parametric studies on effect of the dimension of the enlarged end and properties of adjacent soils on the uplift capacity are also performed. The group effect of anchor spacing is also investigated in this paper. Related Articles | Metrics

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Numerical Simulation for the Progressive Failure in Soil Slopes Using ABAQUS ZHOU Rongfang1, LEI Xuewen1, MENG Qingshan2， LIN Cong1 2012, 26 (4):  56-59.  Abstract ( 3510 )   Save The progressive failure mechanism should be considered in the stability analysis of soil slopes with fissures and expansioncontraction characteristics. This paper presents the numerical analysis results of slope stability analyses using the strength reduction method. Local deformations as well as the development of the failure planes can be numerically simulated by ABAQUS. As a result, the factor of safety and the effects of the slope angle and the soil dilatant angle on the slope stability can be observed. Related Articles | Metrics

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Finite Element Analysis of Sand Drain Consolidations TONG Shuai, SHI Hongyan, ZHAO Qingqiang 2012, 26 (4):  60-63.  Abstract ( 2388 )   Save This paper presents finite element analysis results using ABAQUS. The equivalent planestrain method is used to numerically simulate the vertical settlement, lateral deflection and pore water pressure distribution in soft soils improved by preloading using sand drains. The difference between the measured values and the simulated values are discussed. In general, numerical simulation can satisfactorily predict vertical settlement and the pore water pressure distribution. Related Articles | Metrics

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Revised CamClay Model Based on g(θσ) Method ZHEN Wenzhan 2012, 26 (4):  64-68.  Abstract ( 2820 )   Save Apexes of the MohrCoulomb yield locus in the πplane might result in unexpected singularities in numerical analyses. A shape function, g(θσ), which smoothens the angular hexagon in the MohrCoulomb criterion, is adopted. The revised yield locus becomes a rounded hexagon in the πplane. The paper also compares the differences of the locus in the πplane using the proposed g(θσ) method and the Spatially Mobilized Plane (SMP) criterion. The Lode angle is considered in a new CamClay model modified by the g(θσ) method. A finite element analysis using this constitutive model is performed on an instrumented experimental embankment in Australia. The vertical and lateral deflection of the soils and the pore water pressure dissipations are discussed in the paper. Related Articles | Metrics

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TwoDimensional Discrete Element Simulations of Largescale Direct Shear Tests of Coarse Grained Soils ZHOU Jiehui1, FENG Chunhui2 2012, 26 (4):  69-71.  Abstract ( 2306 )   Save Coarsegrained soils are extensively used as roadbed embankment material for highway construction in the mountainous areas. To obtain the strength and deformation parameters of coarsegrained soils from highly weathered basalts, a series of laboratory largescale direct shear tests were conducted. Based on the particle discrete element software PFC2D, a twodimensional direct shear numerical model was established with soil particles modeled as disks. In the model, the particles size distribution and the parallel bonding contact model (PBM) effects were considered. The direct shear tests were simulated under different vertical pressures. Results indicate that: Under a 1.9×107 N/m of normal and shear stiffness, a magnitude of 8.0×105 N/m for the bond normal and shear stiffness, and 0.39 for the bonding radius multiplier factor, the resulting shear strength indices are 98.33kPa for the cohesion and 27.02° for the internal friction angle, respectively. The shear stress and shear displacement have a good agreement in simulated and tested results. During initial testing, the simulated and tested vertical displacementshear displacements were different. From parameter calibration, it is noted that the friction coefficient among disks increases when the vertical pressure increases from 0.15 to 0.60. Due to the rotation and the stress concentration of the contact pressure, irregular rotational movements of the disks near the shear band were observed. Related Articles | Metrics

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Damage of Petroleum Pipelines by the Geological Hazards in Mountain Areas WU Wenping1,2，HUANG Peng1,2，ZHAO Jiewei1,2， KONG Jiming3 2012, 26 (4):  72-75.  Abstract ( 2358 )   Save With the development of pipeline construction and operations in mountainous areas, more attention has been paid to the effect of adverse geological hazards on pipelines. The geological hazards in mountainous areas cause different types of pipeline damage: unintended exposure and hanging over; excessive deformation and bending, and even fracture that causes leakage and explosion of petroleum products. It is imperative to understand the geological hazards in the mountainous areas in order to provide appropriate preventive measures for the construction of petroleum product pipelines. This paper introduces different geological hazards, such as landslides, debris flows and sinkhole collapses, that are commonly encountered in pipeline construction and operations in the mountainous areas. The effect of these hazards on pipeline alignments is also discussed. The engineering and bioengineering measures that could minimize geological hazards are recommended in this paper. Related Articles | Metrics

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Design of Small Diameter AntiLandslide Bored Piles with Ground Anchor System YANG Chaofa 2012, 26 (4):  76-77.  Abstract ( 2385 )   Save The large diameter antilandslide bored pile is a conventional measure in a landslide remediation design. Under the influence of various industrial design codes, technical documents, as well as construction experience, the diameters of these piles are between 2 and 3 meters with a embedment depth of 1/3 to 1/2 of the pile length below the potential slip surface. With the recent development of ground anchor systems, discussions have been raised regarding the required bored pile diameter and the embedment depth. This paper presents a case history of a remediation using small diameter antilandslide bored piles and ground anchors. Design principles of the remediation work are also introduced. Related Articles | Metrics

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Horizontal Displacement Monitoring of a Deep Excavation with PileAnchor Bracing System ZHANG Qinxi1,2, YIN Wenbiao1,2, YU Fengying3 2012, 26 (4):  78-80.  Abstract ( 2661 )   Save With an increasing utilization of underground space, deep excavation technology is developing rapidly. Monitoring of deep excavation becomes particularly important. Throughout the analysis of slope inclinometers in a deep excavation site in Beijing, the horizontal movements of the supported system are monitored and discussed. Related Articles | Metrics

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Effect of Ash Content on the Mechanical Properties of Red Mud CHEN Jiaqiong 2012, 26 (4):  81-84.  Abstract ( 1826 )   Save Red mud belongs to the alumina tailings. Base on the different chemical process, red mud is subdivided into Sintering Red Mud and Bayer Process Red Mud. It is noted that the mechanical properties of red mud will be altered with the addition of ashes. This paper presents the laboratory test results of two red mud mixtures with different ash contents. Related Articles | Metrics

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Application of BP Neural Network in the Dynamic Calculation of Flyash Dam CHEN Jianbin1, HE Gangyan2, FAN Wei1 2012, 26 (4):  85-87.  Abstract ( 2279 )   Save Considering the uncertainty and complexity of dynamic parameters of a computational model used in the flyash dam simulation, a predictive model of the dynamic parameters of ash dam simulation is established. The sampling pool used in the predictive model is obtained from laboratory tested soil parameters. The model also adopts the predictability of the Back Propagation (BP) neural network. The dynamic response of a flyash dam of a power plant was analyzed and the numerical results were compared with the measured results. This analytical approach provides useful recommendations for the response of a flyash dam under a seismic condition. Related Articles | Metrics

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Analysis of the Relationship between Grade and Deformation of Rock Surrounding in Dabie Mountains Tunnel Mawu Highway ZHANG Guitao1，CAO Chunsheng2, CHENG Kang3, Fu Hai3 2012, 26 (4):  88-90.  Abstract ( 2397 )   Save In this paper, a classification method of rock mass for tunnel engineering in Dabiesan is summarized. Based on the monitored data, three different relationships between the Rock Mass Class and the tunnel deformation are obtained. First, hard and massive rock mass with a Class of II ~ III has a smooth deformation curve. The Class III-V rock mass has a deformation curve similar to the square root symbol. The weak and fractured rock mass has complete elasticplastic perfect deformation characteristics. In tunnel excavation in these rock masses, if the deformation rate has a sudden change, more frequent monitoring is necessary to ensure construction safety. Related Articles | Metrics

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Correlation Analysis of SPTN Values and Cohesion and International Angle of a Clay CHENG Jianguo 2012, 26 (4):  91-93.  Abstract ( 13149 )   Save This paper presents the correlation analysis between Standard Penetration Test (SPT), blow count (N) value, and shear strength parameters of residual cohesive soils from Huanggang Eroded Ridge formations. The data used in the analyses are from the geotechnical exploration of nine (9) projects. A empirical relationship between the SPTN value and the strength parameters, cohesion c and internal friction angle,  φ, are obtained through the regression analysis of 99 N values and 102 tested samples. Related Articles | Metrics

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Influence of Slipped Soil on the Stability of Landslides in Eastern Sichuan Province LI Rui1 ，YU Xiaomin2， WANG Zhentao3 2012, 26 (4):  94-97.  Abstract ( 2263 )   Save Currently, researches on the mechanism of landslides in red gently inclined formations in the Eastern Sichuan Province mainly focus on the change of seepage fields induced by the rainfall. This paper selects the Tiantai Landslide in Xuanhan County, Sichuan Province to study the influence of the slipped soil zone on the stability of the landslide in the area. The shear strength of the samples from the slipped soil zone of the Tiantai Landslide under both natural moisture and saturated conditions are laboratory tested. The test results show that the shear strength of saturated soil samples is significantly less than the strength of the samples under the natural moisture conditions. The Geostudio software is used to model the seepage field change induced by rainfall. The factor of safety for slope stability is computed using shear strength of the slipped soil zones under both natural moisture and saturated moisture conditions. The computational results show that shear strength of the slipped soil has a significant influence on the stability of the landslide. The existing research indicates that the landslide occurred due to the combined effect of both the stress field change and the shear strength reduction in the slipped soil zones induced by the rainfall. Related Articles | Metrics

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Risk Management in Highway Bridge and Tunnel Constructions DING Zhongshan 2012, 26 (4):  98-101.  Abstract ( 2580 )   Save This paper introduces the experiences in risk management and control during the construction of substructures and superstructures of high bridges and culverts, as well as tunnels. Related Articles | Metrics

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Quantitative Evaluation of Uniformity of SoilCement Mixing Columns CHEN Dingan 2012, 26 (4):  102-105.  Abstract ( 3272 )   Save This paper introduces a method of quantitative evaluation of the uniformity of soilcement mixing columns. Related Articles | Metrics

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StressStrain Behavior of the Structured Loess ZHOU Dongliang， HUANG Da 2012, 26 (4):  106-108.  Abstract ( 2368 )   Save Loess is a typical structured soil. It is believed that the characteristics of the microstructure and the fabric of the loess could be reflected in its stressstrain relationship. Both conventional strain controlled isotropic and anisotropic consolidation undrained shear testes on undisturbed loess samples were initially conducted by the GDS triaxial testing system. A series of stressstrain relationships on the were obtained. It is observed that a typical stressstrain curve first demonstrated a steady state for a short period of time followed by a strong strainsoftening behavior. To further explore the behavior of this structured loess, a series of stresscontrolled triaxial compression tests were conducted. It is founded that the stresscontrolled triaxial tests had a better characterization of the microstructure of the loess. The structural strength of the soil is observed at the point of stress failure. Whereas, in the conventional straincontrolled triaxial tests, the constant strain rate usually could not capture the structural strength of the loess. Related Articles | Metrics

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True Triaxial Undrained Shear Tests of a Coarse Sand YAN Quanhui, YANG Xueqiang， Yang guili 2012, 26 (4):  109-111.  Abstract ( 2263 )   Save A series of true triaxial compression tests of Fujian Standard Sand under different cell pressures and intermediate principal stress coefficients are performed on a true triaxial testing apparatus. The stressstrain characteristics of the coarse sand under the undrained conditions are obtained. The effect of the intermediate principal stress coefficient on the deviatoric stress, pore water pressure, stress ratio, and effective principal stress ratio with the coefficient of variation of principal stress is also discussed in this paper. Related Articles | Metrics

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Field Measurements of PileAnchor Supporting Structures in Sandy Cobble Soils in Chengdu LI Hongmei, QIAN Xiao, ZHAO Xiaoqing 2012, 26 (4):  112-115.  Abstract ( 2577 )   Save The case history of a deep excavation using a pileanchor supporting system is presented in this paper. The excavation support system was constructed in sandy cobble soils and was instrumented. The earth pressures, the stress in the piles and the tension force in the anchors were monitored during the excavation. The results indicated that the earth pressures acting on the piles were only 1/6 to 1/10 of the atrest earth pressure. The excavation depth had minor impact on the steel wales. The stress recorded in the pile rebar was only 16.8% of the design strength. The stress loss in the prestressed anchors was observed immediately after the pretension. These data provide valuable information for similar deep excavations in the Chengdu area. Related Articles | Metrics

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Experimental Studies on the Effect of the Low Amplitude Vibrations on the Permeability of Saturated Fine Grained Soils XU Qingjun 2012, 26 (4):  116-118.  Abstract ( 2237 )   Save The saturated fine grained soils are prone to liquefy under low amplitude vibrations. The normal operations of highways constructed over these soils might be seriously affected. In order to minimize the adverse liquefaction effect of fine grained soils during the construction, the impact of low amplitude vibration on the soil permeability is studied using laboratory and field tests. It is concluded that, as the number of vibrations increases, the measured coefficient of permeability tends to first decrease and then decrease for different types of soils. The grain size, gradation and the void ratio of the soils have the significant effect on the soil permeability. References | Related Articles | Metrics

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Studies of Post Grout on the Axial Capacity of Large Diameter Long Bored Piles LU Kunhua 2012, 26 (4):  119-122.  Abstract ( 2452 )   Save The comparative studies on the large diameter, long bored piles in soft soils with and without post grouting are presented in this paper. Based on the instrumented static load test results on both types of piles, it is concluded that the post grouting can effectively improve interaction between pile and adjacent soils. Therefore, the capacity of both end bearing and side friction is obviously increased. Related Articles | Metrics

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Insitu Permeability Tests in Guizhou Basalt Residual Soils TIAN Xiaobo1, LIU Xin2 2012, 26 (4):  123-125.  Abstract ( 2309 )   Save Insitu permeability tests in the basalt residual soils were required in the Biwei Expressway in Guizhou. The doublering permeability method was selected for the basalt saprolite soils with different degrees of weathering. The test results demonstrate that the coefficient of permeability of the reddish brown residual soil is greater than that of yellowish brown soil. The colluvial soils with large degrees of weathering at both sides of the natural slope are slightly more permeable than soils with less degrees of weathering in the middle. The permeability decreases with the increase of the unit weight of the residual soils. Related Articles | Metrics

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Settlement Monitoring of ColumnLoad Transfer Mat System at Shenzhen Airport Parking Apron ZHAN Jianhua1， HU Shenggang2 2012, 26 (4):  126-128.  Abstract ( 2420 )   Save The thick soft and highly compressible marine peaty soils are under the Shenzhen Airport. The columnload transfer mat system was successfully applied in the soil improvement of the parking apron of the airport expansion project. This paper presents the construction aspects of the columnload transfer mat system and the settlement monitoring results. Related Articles | Metrics

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Geological Condition Prediction and Construction Monitoring in Tunnel Excavations PAN Jiangpeng1, ZHU Jianqun1, MENG Qingsheng2, LI Kai1 2012, 26 (4):  129-131.  Abstract ( 2519 )   Save Many geological hazards might be encountered in tunnel excavations and some might adversely affect construction safety. This case history presents the prediction of geological conditions by using ground penetrating radar. Throughout construction, it is concluded that this method could reasonably detect the joints and groundwater in the rock mass in front of the excavation. This information provides bases for the excavation and support. Combining the prediction and the construction monitoring results can provide an effective way to justify the stability of the rock mass and ensure a safe tunnel construction. Related Articles | Metrics

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TSP Advanced Geological Forecast for Unfavorable Geology of Changshan Tunnel WU Bo1, JIANG Dekuan1，JIA Shanpo2, WU Guojun3 2012, 26 (4):  132-134.  Abstract ( 2197 )   Save The geological conditions encountered in the construction of the Changshan Tunnel of Huashan Boulevard in Wuhan are characterized by Karst Geology and a fractured rock mass. These unfavorable geological conditions might adversely affect construction. This paper presents the application of a geological condition prediction technology: Tunnel Seismic Prediction (TSP) in the tunnel excavation. The TSP successfully predicted the karst rock cavities with groundwater between Station K3+180 and K3+144; the fractured rock mass zone between Station K3+144 and K3+114 is also detected before the excavation. Related Articles | Metrics