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20 August 2017, Volume 31 Issue 4 Previous Issue    Next Issue

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Settlement Patterns and Deformation Control of a Subway Tunnel beneath a Highway LIU Jianmei, LIU Yang 2017, 31 (4):  383-386.  Abstract ( 932 )   Save An excessive deformation is often occurred when a tunnel underpass the existing highway. This paper presents a case history of Shenzhen Metro No. 7 Line crossing the GuangzhouShenzhen Expressway. The tunnel excavation was numerically simulated and the deformation results were compared with the construction observation data. The observed settlement data indicate that the ground settlement has a normal distribution. For the double tunnel excavations, when the net spacing between the tunnels is smaller than one diameter of the tunnel diameter, the settlement through on the ground surface has a single V shaped other than W shaped. When the tunnel at the highway is not perpendicular, the eccentric pressure might influence the tunnel liners. The results also indicate that the full section grout can have a better control of the ground subsidence but grouting might also cause ground heaving. Combining the numerical analysis and the construction observation the ground deformation can be effectively controlled. Related Articles | Metrics

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Design and Construction of a Deep Excavation Support under the High PlateauEnvironment CHEN Jinghe 2017, 31 (4):  387-389.  Abstract ( 1039 )   Save This paper presents a case history of a deep excavation supporting system that had the combination of sloped ground, soil nailing and soldier pile and lagging wall in Qinghai High Plateau. The groundwater level control was critical to the success of this project due to the excessively large thickness of the layer layers which has a high groundwater level, large permeability and high potential of occurring of quick sand during the construction. Methods that are feasible for the sealing, collecting water and dewatering were compared and the point well method was selected for this project. The design and construction aspects of the point well techniques are introduced in the paper. Related Articles | Metrics

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Deformation and Safety Evaluation of a Large Deep -Excavation in Nanchang Metro Project CAO Pengfei 2017, 31 (4):  390-393.  Abstract ( 1092 )   Save The safety of the deep excavation is one of the important factors in the urban construction. Conventional deep excavation support analysis methods are equivalent bean method; elastic beam method and finite element method. Elastic beam method has the advantage of reliable and is practically used in the engineering projects. The finite element method has the clear mechanical concept and has a relatively high accuracy. This paper presents a case history of large deep excavation in Nanchang. Both elastic beam and finite element methods are used in the analyses of the supporting system and the impact of the unsymmetrical loading on the safety of the supporting system is also evaluated. The results indicate that the supporting system used is technically sound and the safety requirements are met. The solider pile deformation controls the ground subsidence. Asymmetric loading has the impact on the deformation on the excavated area and ground subsidence and it has less impact on the stresses in the supporting support system. Related Articles | Metrics

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Impact of a Cut and Cover TunnelConstruction on the Adjacent NanningGuangzhou HighSpeed Rail JIA Shiping 2017, 31 (4):  394-396.  Abstract ( 1115 )   Save A segment of cut-and-cover tunnel is parallel to the existing Nanning-Guangzhou high speed rail which is under construction. The distance from the edge of the track to the edge of the excavation is 20.5 meters. It is concluded that impact of the cutandcover tunnel construction on the existing high speed rail should be evaluated. The safety evaluation criteria are established from the various design codes and existing construction practice. A typical section that represented the worst case scenario (distance between the excavation and the rail track, large excavation depth and unfavorable subsurface conditions) was selected for the finite element analysis. The influence of the active and inactive rail track on the cut-and-cover tunnel excavation were simulated. Related Articles | Metrics

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Selection and Design of Uplift Foundations foran Underground Parking Garage LV Hengzhu, LI Delin 2017, 31 (4):  397-401.  Abstract ( 1006 )   Save In the selection and design of the uplift foundation for an underground parking garage of a residential community, all feasible foundations were compared with both constructability and cost based on the site specific subsurface conditions. The optimized foundation type that can meet the bearing capacity requirements and also cost effective. The static loading tests were performed on two different pile types: prefabricated, prestressed reinforced concrete pipe piles and bored and castinpaced reinforced concrete piles. The testing under the natural ground and excavated conditions indicate that the uplift capacities are significantly different. Therefore, during the design stage, the pile testing conditions should be specified. Related Articles | Metrics

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Application of the Dynamic Compaction Method in Loess Soils CAI Ruifeng 2017, 31 (4):  402-405.  Abstract ( 894 )   Save The detailed subsurface geotechnical investigation results indicate the poor and heterogeneous conditions underneath the proposed coalburning boiler of No. 2 CoalSteam Converting Station of Fengcheng Oil Field. The subsurface soils could not meet the design requirement as well as a wetting collapse exists in the soils. The feasibility of the soil improvement analysis indicates that the dynamic compact is the most cost effective method for the strengthening the soil strength and eliminating the wetting induced collapse in loess soils. The third party insitu testing results before and after the improvement demonstrated the success of applying this method. Related Articles | Metrics

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The research about Secondary liner supporting time In soft rock highway tunnel WU Qingquan, LI Haohui, HUANG Jiahua， HUANG Baosheng 2017, 31 (4):  406-409.  Abstract ( 1140 )   Save In the process of construction of carbonaceous rock road tunnel, it is of great significance to determine the optimal timing of the second lining support, and the reference standard given in the highway specification is one-sided and not targeted. A highway tunnel in Guangxi Carbonaceous Area is the object of study Considering the characteristics of collapse, expansion and creep of surrounding rock, FALC3D software is used for numerical analysis, combined with on-site monitoring data to determine the best timing of the second lining support and guide the construction. Related Articles | Metrics

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Impact of an Underpass Excavation on the Underground Gas Pipelines CHEN Jun1, SUN Jizhu2 2017, 31 (4):  410-412.  Abstract ( 1031 )   Save The excavation of the urban pedestrian underpass often induces the undesired deformation and even damage to the underground utilities nearby. The pipeline is idealized as the beam on the elastic soil foundation and the longitudinal bending formula of the underground pipelines is derived. The failure criterion for the flexible pipelines with rigid joint is also proposed. Assuming that the settlement trough of the pedestrian underpass has the shape of the Gaussian normal distribution, the surface and subsurface settlement prediction formula and their relationships among parameters are presented. Based on the underpass construction monitoring data, the safety analysis case history of a gas line affected by the underpass excavation is presented. Related Articles | Metrics

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Analysis of Leaking in the Kubia Hydroelectricity Station GAO Xiaoyu 2017, 31 (4):  413-415.  Abstract ( 922 )   Save The underground spacing for the Kubia Hydroelectricity Project was experiencing the unexpected water leaking. The evaluation concluded that the confinement of the bedrock, differential settlement, temperature variation and improper design are the major factors that contributed to the unexpected water leaking. The cement and chemical grout and well as drainage design were applied at various locations based on the site conditions. Related Articles | Metrics

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Consolidating Grout Testing in a Basalt Bedrock with Columnar Joints for a Dam Foundation MA Feng 2017, 31 (4):  416-421.  Abstract ( 975 )   Save As a special rock mass, rock mass with columnar joints has a different geological structure with the conventional rock masses. The columnar joints are generally having irregular and variable joint plane and the cross section of the columnar joints are also irregular and have incomplete incision. Joints and fissures are well developed inside the columnar structures and these defects contribute to the relatively lower modulus and low shear strength. The concentrated split zones can also be observed in same rock mass. As the foundation of a concrete arch dam, the rock mass is required to have sufficient bearing capacity and stability. However, due to the unique tectonic structure of the columnar jointed rock mass with welldeveloped structural planes, it is necessary to evaluate the performance of the basalt bedrock with the columnar joints under the loading conditions as well as the impact of the consolidating grout at the faulted and broken zones on the integrity, strength and stiffness parameters. The consolidating grout reduced the deformation resistance, increased the shear strength and remediated the seepage at the structured plane of the rock mass. Related Articles | Metrics

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Embankment Fill Materials Design of Algeria 175 Railway Following French Standard YI Jia 2017, 31 (4):  422-427.  Abstract ( 1036 )   Save This paper presents a case history of the backfill design aspects for the Algeria Rail Line 175 embankments using French design specifications. The French design specifications requirements in the rail embankment construction are also introduced. The French code in the geotechnical material classifications, backfill types, location of the backfills, requirements on the compaction of the backfill materials are discussed. The French code and Chinese code are compared. The different and common points in both design specifications are presented. Related Articles | Metrics

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Impact of the Excavation of Pumping Station Pipeline on the Bridge Foundations of Yanjiang Expressway in Shenzhen XU Mingbin, CHENGuoguo 2017, 31 (4):  428-430.  Abstract ( 1032 )   Save The impact of engineering excavation on the adjacent foundations is more and more frequently encountered in the construction. In this paper, the influence of the pipeline excavation for a pumping station in Shenzhen on the nearby bridge foundations is numerically analyzed. The process of the excavation is simulated from the initial ground stress state to the final excavation and the stresses in soil as well as in the bridge foundations are obtained. The safety of the pile bridge foundation is evaluated in accordance with the current code and the results are satisfactory. Related Articles | Metrics

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Risk Evaluation of Under Sea Tunnel Excavation by Large Diameter TBM XIAO Guanping 2017, 31 (4):  431-434.  Abstract ( 1225 )   Save As an important pass way underneath the inner harbor of unban Shantou area, the SuAi Pass Project processes many potential hazards induced by the tunnel construction excavated by the large diameter Tunnel Boring Machine (TBM). Based on the project construction methods and sequences, the potential risks induced by the adverse engineering and hydrological geology conditions as well as construction techniques are identified. The risk levels of the shielded tunneling segment are quantified by using the risk level evaluation and expert system methods. The sources that might result in high risks are evaluated and the method of controlling these risks are also proposed. Related Articles | Metrics

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Design and 3D Analysis of the Supporting System of a Deep Excavation near the Subway Tunnel QIAO Liping1,2,3 2017, 31 (4):  435-439.  Abstract ( 1039 )   Save Very restrictive requirements are imposed on the excavations that are very close to the active operational subway. This paper presents a case history of the deep excavation of Rongchan Houhai Building, which is very close to a subway. The challenges in the design and construction as well as the approaches used to overcomes these difficulties. Three dimensional finite element analyses were used to simulate the entire excavation. The deformation results in the numerical analysis were compared to the field observed data. Related Articles | Metrics

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Application of Visual Modflow in Obtaining Seepage Parameters in a Steeply Inclined Heterogeneous Aquifer FENG Aiguo 2017, 31 (4):  440-442.  Abstract ( 1057 )   Save The bedrock underlying a subway station is steeply inclined and can be considered as an independent aquitard. The soil above the bedrock is a heterogeneous steeply inclined aquifer. The current analytical solution methods could not be readily applied. The Visual Modflow was used to establish the seepage model in this nonuniform aquifer. The seepage parameters can be obtained from the back analysis results. Related Articles | Metrics

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Numerical Analysis of the Effect of Blasting In Tunnel on the Vibration of the Ground Surface WANG Ju 2017, 31 (4):  443-448.  Abstract ( 851 )   Save With the development of tunnel construction of the expressway in mountains areas, the vibration of the ground surface caused by the blasting construction in the tunnel has been increasingly an engineering concern that to be addressed urgently. Focused on the safety issues of the impact of the blasting in the tunnel on the vibration at the ground surface, along with the subsurface conditions at the Tiaohuapo Tunnel of the Fifth Contract Section of the HuaxiAnshun Expressway, the numerical model is established by using the commercial finite element analysis software MIDAS/GTS NX. The ground vibration velocities are obtained at various conditions. The results indicate that, with the increase of the blasting action time, the resultant total particle vibration velocity, horizontal as well as vertical variation velocities demonstrate an increase before the degradation. The multi point Gaussian function can be used to fit the relationship between the peak vibration velocity and the distance to the center of the blasting. Related Articles | Metrics

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Expanded Shaft Piles for the Excavation Supporting and PLAXIS Analysis Results YU Peng1, LI Qimin1, CHEN Lulu2 2017, 31 (4):  449-452.  Abstract ( 1190 )   Save Theexpanded shaft pile is a new kindof supporting form.This paper presents application of the expanded shaft piles in the excavation supporting and the PLAXIS analysis results. The performance of this new supporting system under the lateral earth pressures are discussed. The numerical analysis using MohrCoulomb (MC) and Hardening Soil (HS) models. The paper provides suggestions of practical application of the expanded shaft pile and the constitutive model selections in the numerical analysis. Related Articles | Metrics

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Numerical Analysis of Soldier Piles in a Deep Excavation Supporting System ZHOU Yi, LI Hongmei 2017, 31 (4):  453-458.  Abstract ( 942 )   Save The need of high raised buildings and underground spaces increases with the urban development. As a result, the applications of deep excavation supporting systems are more and more popular. The cost effective and construction safety still required further research into the supporting system. The paper presents a case history of deep excavation of Beijing Sijiqing Drinking Water Emergency Center. The deformation of the excavation supporting system is evaluated throughout the theoretical analysis, laboratory testing and numerical simulations. The three dimensional FLAC3D analysis results indicate that, with the increasing of the excavation depth, the deformations in soil mass and the supporting system are also increasing. The ground anchors can effectively control the deformation in the supporting system. The excavation depth reaches the maximum depth and the deformations in the supporting system also become the maximum. Related Articles | Metrics

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The Characteristic of East Zhejiang Weakly Cemented Conglomerate OUYANG Taojian, CHENG Chunhong, LIANG Long 2017, 31 (4):  459-461.  Abstract ( 1397 )   Save The conglomerate in east Zhejiang is generally shallow deposited and has weak cementation.  The cored samples from the boreholes are usually in loose sand gravel shape. The geotechnical investigations are usually misclassified as sandy gravelly layer or completely weathered bedrock. This weakly cemented bedrock is usually assumed to have excessively low bearing capacity. The geotechnical properties of the weakly cemented conglomerate rock layer are evaluated and the axial capacity of piles into the type of bedrock is also studied. The results indicate that this cemented conglomerate can be classified as a soft rock. Although the cored samples are loose and have low recovery, the original strength of the rock could be high. The bedrock is moderately weathered and can be served as load bearing layer of the shallow foundations without strengthening. For the heavily loaded structures or structures with high deformation requirements, the post construction grouting or manually excavated enlarged base caisson can be used. Further, the construction technique should be improved and the rotary drilling machine is a better technique. Related Articles | Metrics

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Parameter Sensitivity Analysis of Mountainous Highway Slopes WEI Cui1,2,3, RUAN Hang2, WANG Bin2 2017, 31 (4):  462-464.  Abstract ( 1165 )   Save A left cut slope in ChangJi Expressway is evaluated in this project. The factors that might affect the slope stability are: slope angle, height of slope; cohesion, internal friction angle, and elastic modulus. The sensitivity of these factors to the slope stability are analyzed by using strength reduction method in the finite element analysis. The analytical results indicate that the sensitive parameters that sequentially listed as follow: slope angle, slope height; internal friction angle; cohesion and elastic modulus. The slope angle and slope height are the factors that are most affecting the slope stability. Related Articles | Metrics

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Shear Strength Characteristics of a Compacted Red Clay in Kunming Area SUN Xiwang1, XU Yunlong2, YANG Guoyue2, LI Liangji2 2017, 31 (4):  465-467.  Abstract ( 1104 )   Save Red clay is widely distributed in Southwest China. It has practical engineering importance to study the stressstrain characteristics of the compacted red clay. Both direct shear tests and triaxial shear tests were performed on a series of the compacted red clay samples with different moisture contents and degrees of compaction. Direct shear test results and triaxial shear test results on soils with the samples having the same degree of compaction were compared. The following conclusion can be summarized: The shear strength parameters increase with the degree of compaction and reduce with the moisture contents. Higher tested cohesion are occurred at higher moisture contents or higher degree of compaction. When the moisture content is lower than the optimum moisture content in the Proctor Test, it has more impact on the cohesion; whereas, when moisture content is higher than the optimum moisture content, it only has minor impact on the cohesion value. The shear strength of the compacted red clay is linearly proportional to the moisture content and the degree of compaction. Both direct shear test and triaxial shear test demonstrate similar trends with moisture content as well as the degree of compaction but the shear strength magnitudes are different. The cohesion value obtained from direction shear test is only 0.58 of the value obtained from triaxial shear test. The internal friction angle obtained from the direct shear test is 1.34 times of the value from the triaxial shear test. Related Articles | Metrics

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Fractal Approach on the Texture of the Reticulated Red Clay SONG Huijuan1,2, LI Jianzhong1,2 2017, 31 (4):  468-471.  Abstract ( 1165 )   Save The texture structure which includes the red and white textures is the most important characteristic of the reticulated red clay. The IPP image processing software is used to study the microstructures of the reticulated red clay in this paper. After the preprocessing which includes the image enhancement, image segmentation and the image binarization, the characteristic parameters that reflecting soil microstructures can be obtained. By studying the fractal dimensions of the reticulated red clay samples, the differences of fractal structure about reticulated red clay in red and white can be differentiated for the engineering applications. The results indicate that the size of the reticulated red clay has the fractal feature and the fractal dimension is between 1.06 and 1.39. The red textured samples have a higher selforganization, gradation and more complex than those of the white textures. Related Articles | Metrics

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Improving the Energy Utilization Rate in the Practical Application of Electro-Osmosis ZHU Junlin 2017, 31 (4):  472-475.  Abstract ( 848 )   Save The low energy utilization of the electroosmosis most is one of the major issues that limiting its practical applications. In order to improve the energy utilization rate, reduce the electrode corrosion and promote the application of the electroosmotic method in the practical engineering, this paper mainly discussed the causes of the huge energy consumption of the electroosmotic method. Based on the indexes of electrolyzed water reaction, interface resistance and soil water content, three methods of reversing electrode, intermittent energization and changing electrode materials were compared and the optimization scheme was put forward. At the same time, this paper explained the reasons why these three methods can improve the energy utilization rate based on the electrochemical theory. Related Articles | Metrics

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Monitoring and Analysis of the Ground Subsidence of a Natural Gas Storage Cavern in Salt Rock HE Chunhai1, YAO Wei1, LIU Yugang1, CHEN Feng2 2017, 31 (4):  476-478.  Abstract ( 1083 )   Save The underground spacing formed by the salt extractions can be reused as the natural gas storage facilities. During the operation of the natural gas storage facilities, the ground subsidence might occur as the creep of the salt rock mass and the contraction of the salt rock cavern. It is important to establish an observation network to capture these ground deformations. This paper presents the ground subsidence observation and evaluation results of China’s first natural gas storage facility in the salt rock caverns. The results indicates that the ground subsidence is closely correlated with the salt rock carven contraction. Related Articles | Metrics

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Comparative Analysis of Ground Vibration Parameters during the Dynamic Compaction LIU Jian 2017, 31 (4):  479-480.  Abstract ( 974 )   Save The measured vibration parameters during the dynamic compaction indicate that, with the increasing of compaction times, the peak particle velocity, and acceleration are first increasing, then gradually reach to a stable values, the vibration parameters finally reduce. The crater depth changes with the vibration parameters. Related Articles | Metrics

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Soil Stratigraphy Classification Based on the Geotechnical Statistic Analysis ZHOU Wenhai1， LI Yongdong2 2017, 31 (4):  481-485.  Abstract ( 1036 )   Save The soil stratigraphy and statistical analysis of the geotechnical engineering parameters are the important content of the geotechnical investigation. The accuracy of soil stratigraphy classification directly affect the site soil geotechnical engineering performance evaluation. In the conventional geotechnical investigation, the preliminary soil layers are classified based on the geological sediment conditions and soil parameters. The layers are finalized based on the laboratory test results and the soil layers can be adjusted. This paper presents a case history of the geotechnical investigation in Wangjing area of Beijing. The geotechnical engineering statistical works in areas with rich tested data are proposed. The soil parameters for major soil layers are summarized and the standard deviation, coefficient variations are also presented. Related Articles | Metrics

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Optimizing the Sheet Piles Embedment Depth Calculations TANG Shuyong, WANG Zeyun, ZHOU Tianyi, ZENG Wufeng， WANG Yifan 2017, 31 (4):  486-489.  Abstract ( 1149 )   Save The theoretical and basic assumptions in the application of equivalent beam method in the deep excavation supporting design are introduced in this paper in detail. A conversion formula is proposed based on the correlations in the active and passive earth pressures and this formula is then introduced in simplifying the embedment depth of cantilever walls. This new approach is also verified a practical deep excavation project. In the application, the embedment depth of the sheet piles can be adjusted based on the monotonic properties of the fitting function, as well as the soil properties and state. The effect of the zero earth pressure points from various methods on the supporting structures are also analyzed. Related Articles | Metrics

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The State of Practice of Green Construction in China WANG Hongbin, BAO Zhangmin, WANG Wenzhe, XU Youna 2017, 31 (4):  490-494.  Abstract ( 1201 )   Save This paper presents the review of the state of practice of the green construction in China. The current construction industry has the characteristics of having large scale, high value and rapid development. There is no regulatory rule and no actual data regarding the consumption of these materials. The current construction industry status is not ideal for the sustainable development and the goal of constructing a society of resource saving and environment friendly. Based on the “Green Construction Guidelines” issued by the Ministry of Construction, this paper introduces the concept of the green construction from aspects of environmental protection, material saving, water saving, and energy saving. The areas that can be improved in the industry are suggested. Related Articles | Metrics

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Seismic Active Earth Pressures on the Retaining Walls WANG Zixu, SUN Yong, SHANG Benfeng, FENG Hui, ZHAO Min 2017, 31 (4):  495-499.  Abstract ( 1230 )   Save An active seismic pressures acting on a retaining wall is derived with differential thin layer method. The retaining wall has vertical face and horizontal level, the backfill material is cohesive and the interface between the back of the wall and the backfill material follows cφ  soil relations. The vertical and horizontal seismic accelerations are acting on the failure plane. It is concluded that the conventional seismic and static active earth pressure formulas are this generic formula under special conditions. The force equilibrium method applying at the toe of the retaining wall (Rankine Earth Pressure), has the same total earth pressures as the value derived from the differential thin layer method. However, the point of acting obtained from the differential thin layer method is higher than the conventional method. Related Articles | Metrics

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Considerations on the Hydrogeological Reconnaissance in Geotechnical Investigations FANG Yuming 2017, 31 (4):  500-502.  Abstract ( 1189 )   Save The hydrogeological evaluation is an integrate part of the geotechnical investigations. Some commonly used hydrogeological related terminologies in the geotechnical investigations, such as, aquifer, water productivity, permeable layer, aquitard layer, are discussed in the paper. It is more reasonable to classify the groundwater that is trapped at the upper unsaturated layer as the perched water. Suggestions on the recommendation of hydrogeological parameters in the investigation as well as the aspects of the buoyancy design groundwater table are proposed. In order to accurately evaluate the site hydrogeological conditions, larger scale site evaluation work as well as experience are necessary. Related Articles | Metrics

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Measurement of the Hydraulic Conductivity of Soil-Cement Mixed Samples Using a Flexible Wall Permeameter with Double Drainage Lines WANG Wei 2017, 31 (4):  503-506.  Abstract ( 1152 )   Save Disadvantages existed in using the conventional seepage device for the measurement of the permeability of soilcement mixed soils, this paper presents an improved flexible wall permeameter utilizing the double drainage lines for the measurement of the hydraulic conductivity of soilcement mixed samples. A rubber membrane is introduced to wrap the side of the specimen and side seepage can be avoided under the confining water pressure. Four drainage lines are used to facilitate the sample saturation and eliminate the air bubbles in the sample. The improved device was used to measure the permeability of the soilcement mixed samples in an estuary reservoir project in Yangtze River under four different hydraulic gradients. The relationships between the seepage rate and the hydraulic gradient were obtained. The results indicate that the seepage within the tested soilcement soil samples is laminar flow following Darcy’s law. This improved device can also be used in simulating the insitu seepage conditions. Related Articles | Metrics

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Water Injection Test in the Collapsible Loess Soils WANG Hongyun, ZHOU Ren 2017, 31 (4):  507-512.  Abstract ( 990 )   Save The collapsible loess soil deposits underneath the Phase I Underground Utility Project of Lanzhou New District. In order to verify the effectiveness of the water injection method for the wetting collapse potential reduction, 9 different trial test zones were established. The impact of the water injection spacing, duration of the water injection, as well as the amount of water injected are evaluated and the settlement at the ground surface are correlated. Related Articles | Metrics

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Shear Strength of Compacted Granitic Residual Soils TANG Zhenghong 2017, 31 (4):  513-515.  Abstract ( 1140 )   Save In order to evaluated the shear strength characteristics of the remolded granitic residual soils with various degrees of compaction, extensive laboratory tests were conducted with samples under three different moisture contents and various degrees of compaction. The maximum dry density of the granitic residual soil was obtained through Proctor test. A series of consolidated direct shear tests were performed to evaluate the relationship between the shear strength and the degree of compaction. The results con lead to the following conclusions: 1) under the lower degree of compaction, the shear strength increase with the deformation value; at lower moisture content, with the increase of the degree of compaction, the shear strength demonstrates the reduction of the residual strength after the peak strength and the fragile failure mode can be observed. 2) Under the same moisture content, the internal friction angle and the apparent cohesion increase with the degree of compaction. 3) Under the same degree of compaction, the internal friction angle obtained from the consolidated direct shear tests is insensitive to the moistures content but the apparent cohesion is relatively sensitive to the moisture content. Related Articles | Metrics

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Factors Affecting the Shear Strength of Granite Residual Soils TANG Weiye1， JIAN Wenbin2 2017, 31 (4):  516-520.  Abstract ( 972 )   Save A serious of direct shear tests on granitic residual soil samples from Fuzhou Software Park Project with SDJI direct test device. This device is electrically powered and strain controlled and has three different shearing speed. The objective of this study was to establish the relationship among the shear strength and the various dry densities as well as different moisture contents. The test results indicate that, under the same dry density, the cohesion and internal friction angle are proportional to the moisture content when the moisture content is low. When the moisture content exceeds a threshold value, the shear strength parameters are inversely proportional to the moisture content. The threshold moisture content is close to the optimum moisture content in the Proctor Test. Under the same moisture content, the shear strength parameters are linearly proportional to the dry density. Related Articles | Metrics

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Size Effect on the Shear Strength of Granitic Residual Soils LIN Kongbin1,2,3， KE Guogui4 2017, 31 (4):  521-525.  Abstract ( 1076 )   Save To investigate the soil grain size as well as the sample size effect on the stressstrain characteristics of the granitic residual soils, consolidated undrained triaxial shear tests were performed on remolded granitic residual soils with grain sized greater than 5mm removed under three different sample diameters for the triaxial shear tests. The results indicate that the stressstrain curves from samples tested under different diameters are similar with different stress magnitudes; the presence of the large grain size in the sample will increase the tested effective cohesion and reduce the internal friction angle. When the large grain soils are removed from the samples, with the increase of the sample diameters, the tested effective cohesion increases and the effective internal friction angle reduces. However, the total cohesion reduces and total internal friction angle increases with the sample diameters. In general, the sample size has a larger impact on the effective cohesion and less impact on the effective internal friction angle. Related Articles | Metrics

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Self-Balanced Pile Loading Test Method in A Bridge Project WANG Ying1, WANG Jiayi2 2017, 31 (4):  526-528.  Abstract ( 887 )   Save The pile foundation of Leqing Bay Bridge in Zhejiang has the characteristics of high bearing capacity, large diameter and the piles are in the marine environment. The selfbalanced method was used to test the capacity of 5 piles. And the ultimate bearing capacity of the single pile was analyzed by the simplified equivalent conversion method and precise conversion method. The loading test results showed that the simplified equivalent conversion method can meet the engineering requirements. Further analysis is needed in order to obtain the reasonable value of the conversion coefficient K in different soils. Related Articles | Metrics

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Application of the Automatic Monitoring in the Rainfall-Induced Landslide MO Jinfeng1,2， ZHANG Yu1,2， QIU Jianjin1,2, LI Aiguo1 2017, 31 (4):  529-532.  Abstract ( 1029 )   Save A landslide occurred at the hotel and residential area constructed at along the natural slope was monitored with an automatic instrumentation system. Factors that leads to the rainfall induced landslide were investigated. The instrumentation system was consisted of soil moisture probes, tensiometers, piezometers, slope inclinometers and a rain gauge. These probes are interconnected and data acquisition was completely automatic. The monitoring program started at the dry season of 2011 till the landslide occurred in the rain season in 2012. This paper introduces the design and installation of the monitoring program. It is concluded that the significant reduction of the matrix suctions and increased moisture content in the soil due to the precipitation were the major factors that leading to the slope failure at shallow depth. Related Articles | Metrics

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Comparison Study between Cone Dynamic Penetration Test and Soil Sampling Test in Fills BAO Yanjun， WANG Zengchao 2017, 31 (4):  533-536.  Abstract ( 1276 )   Save This paper introduces the testing methods of cone penetration testing and conventional soil sampling. In the quality control of the site compaction, cone dynamic penetration test has the advantage of short testing period, low cost and continuous testing profile. A comparative study between the cone dynamic penetration testing and soil degree of compaction has been conducted at the same site. The nonlinear regression relationship can not only provide the uniformity of the back fill soil but also the degree of compaction of the backfill soils. It is concluded that the cone dynamic penetration test can be used to have an effective evaluation of the degree of compaction of backfill soils. Related Articles | Metrics