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20 December 2016, Volume 30 Issue 6 Previous Issue    Next Issue

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Highway High Cut Slope Construction Monitoring YU Jiewen 2016, 30 (6):  619-621.  Abstract ( 1019 )   Save The highway construction plays an important role in the transportation industry. Under the influence of topography and climate, the stability related problems of the high cut slopes are frequently encountered and some of them are severely affected the construction schedule. A high cut slope between Stations K4+700 and K4+985 was instrumented. The surface deformation, stress in the ground anchors, displacement are monitored and analyzed. These factored are beneficial to the cut slope stability. Related Articles | Metrics

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Application of Excavation Support System in a Very Large Deep Excavation BAO Huiming, LIU Wenbin, YU Lei 2016, 30 (6):  622-626.  Abstract ( 1002 )   Save A very large deep excavation project is located at the east and south sides of Fengshun Street and north side of the People’s Bank of China. The planned building area is approximately 91,040 square meters and the deepest excavation is approximately 19.5 meters below the proposed ground floor. Due to the high groundwater level, the excavation support is necessary otherwise the side soils would be collapsed under the seepage force. Based on the excavation requirements and the superstructure types, different excavation support systems are used: Segment AB was designed using combined soil nailed wall supporting system; Segment BCD used soil nailed wall plus soldier pile with ground anchor system; and Segment DEA utilized soldier pile with ground anchor as the primary support measure. The construction procedures, quality assurance and insitu monitoring at each segment are also presented in the paper. Related Articles | Metrics

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Application of Water Surcharge in Vacuum Preloading For the Marine Soft Mucky Soil Improvement LIU Baochen1, ZHENG Yuan1, XIE Yanhua2, ZHANG Binghui1, CHEN Ya1 2016, 30 (6):  627-630.  Abstract ( 1044 )   Save This article introduced construction techniques, construction process and specific parameters of marine soft mucky soil improvements by water surcharge and vacuum preloading method. The observed settlement data from the ground surface during the construction indicate that the settlement rate reduces with time and the primary consolidation settlement rate tends to converge. The paper also compares the results of laboratory tested physical index properties, cone penetration and standard penetration test before and after the surcharge. The results indicate that the soil properties improved by the surcharge operation. Further, the plate loading tests performed on the surcharged soil verifies effect of the soil improvement. Related Articles | Metrics

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Engineering Geology Challenges in the Sandaogou Forest Farm Hydropower Station Project LIU Xiubao, XING Xufei, ZHANG Wei, SU Qing 2016, 30 (6):  631-633.  Abstract ( 1292 )   Save The major geology challenges in the Sandaogou Forest Farm Hydropower Station Project are：low dip angle joints in the bedrock of dam foundations; stability of rock mass surrounding the intake water tunnel; pressurized water pipes and rock slope stability at the power house. This paper presents the results of the geotechnical investigations. The geological, lithological and topographical evaluations at the proposed site are systematically presented. The stability of the intake water tunnel is evaluated throughout the rock mass classification process. Finally, the stability of the rock slope is numerically investigated. The engineering mitigations and recommendations for the major issues encountered in the constructions are also presented in the paper. Related Articles | Metrics

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FLAC3D Study of the Effective Length of the Ground Anchors in Anchored Soldier Pile Reinforced Slope in Jishou under Seismic Conditions PENG Wenxiang, JI Qiang 2016, 30 (6):  634-636.  Abstract ( 1178 )   Save The theoretical aspects of the soldier piles with ground anchors in the landslide remediation, especially under the seismic conditions, are not explicitly explained and are left behind the practical applications. The current practice does not have a rational and reliable method for the determination for the required length of ground anchors. This paper present a method for selecting the length of the ground anchors under certain subsurface conditions for the landslide remediation projects. The numerical analysis under seismic conditions was performed using FLAC3D and the results were consistent with the observed data. Related Articles | Metrics

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Numerical Analysis of Piled Raft Foundations of a Very High Raised Building CHEN Ping 2016, 30 (6):  637-640.  Abstract ( 2289 )   Save The piled raft foundation of the structural core cylinder of a very high raised building is numerically analyzed from three different model approaches by using a commercial software YJK. These three models are: computational model that not considering the stiffness of the superstructure; computational model that considering the stiffness of the superstructure and the computational mode with variable adjusted stiffness. The results indicate that, the model that considers the stiffness of the superstructure and the compatibility of the foundation can effectively the steel reinforcement in the piled raft foundations. With the enough pile axial capacity, the deformation of the piled raft foundation can be controlled through the adjustment of the superstructure stiffness. Related Articles | Metrics

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Pull-out Test Monitoring Procedures and Their Engineering Applications LIN Canyang 2016, 30 (6):  641-644.  Abstract ( 1127 )   Save The pullout test is one of the important quality assurance measures in the installation of the ground anchors. The current engineering practice measures the ultimate load and its deformation. However, abnormal could be presented under various incremental loadings. Currently, no procedures are defined for the excessive elongation of the ground anchors. This paper presents a ground anchor pullout test control procedure by using the basic material properties. The deformation under the incremental loads can be calculated. The calculated values are found to be consistent with the observed values. Related Articles | Metrics

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Application of Ground Anchor with Lattice Beam in the Rehabilitation of a Tilted Wingwall of a Gravity Bridge Abutment XU Hongke1, CHENG Luping1, WANG Huajun2 2016, 30 (6):  645-647.  Abstract ( 1267 )   Save After years of service period, some of the gravity abutments demonstrate various degrees of performance issues that might be adversely affect the safe operation of highways. The lattice bean with ground anchor is a relatively popular and matured method and is widely applied in various mitigation projects. The tension ground anchor with lattice beams at both sides of abutment approach is rarely used. A tilted gravity abutment wingwall at Station K153+478 of YongTaiWen Expressway was rehabilitated by using this technique. The design and construction procedures of the tensioned ground anchor with lattice beam are introduced in this paper and the results are satisfactory. Related Articles | Metrics

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Energy Approaches of Earth Pressures Acting on the Double-Row Pile Excavation System LIU Hancheng, ZHANG Xiaoling， YOU Jinjian 2016, 30 (6):  648-650.  Abstract ( 1028 )   Save The earth pressures acting on the doublerow pile excavation system are deduced by using the energy approach and the earth pressure analysis parameters are recommended based on the characteristics of the doublerow excavation system. The results indicate that, with the increase of the excavation depth, the differences of calculation earth pressures between the energy theory and the Rankine theory are also larger and larger. The source of the earth pressure differences is mainly from Rankine theory assumptions of ignoring the friction and the space effect. Whereas, the earth pressures obtained from the energy approach is more reasonable. When the calculation coefficient is greater than 0.75, the abnormal results are obvious since the space effect in the doublerow excavation supporting system is significantly reduced. The rare row pile serves more like a ground anchor. At this situation, the accuracy of calculated earth pressures is not satisfactory. Related Articles | Metrics

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Modified Cam Clay Model Parameters in ABAQUS from Triaxial Tests LV Yang 2016, 30 (6):  651-657.  Abstract ( 3541 )   Save Numerical analysis has more and more applications in the practical geotechnical engineering projects and the Modified Cam Clay Model is a popular constitutive model in these analyses. A twodimensional axisymmetric model was established in commercial finite element software ABAQUS with both soilwater coupling effective stress and automatic time spacing approaches. The model parameters in the ABAQUS were validated in the triaxial tests on normally consolidated and overconsolidated soil samples under consolidated drained and undrained conditions. The parametric studies can be performed in the ABAQUS by using the validated parameters. Related Articles | Metrics

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A Time Domain Superposition Method for the Fitting of Response Spectrum with MultiDampings CHEN Sheng 2016, 30 (6):  658-661.  Abstract ( 1006 )   Save In nonlinear dynamic response analysis of structures, the time history of ground motion is often needed to fit the response spectrum. In this paper, the time domain adjustment of multidamping response spectrum fitting is studied. Based on the timedomain superposition wavelet function method which is widely used in single damping fitting, the simulation algorithm is extended to the multidamping fitting considering the interaction of each damping superposition function. Use a measured ground motion as an example, the ground motion was adjusted and fitted to the normalized response spectrum in accordance with both Chinese normalized response spectra and the European normalized response spectra. The results show that the fitting error can be controlled within allowable range using the proposed multidamping domain adjusting method. Related Articles | Metrics

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Three Dimensional Finite Element Analysis of Slope Stability Under Poole Water Level Fluctuation and Precipitations FANG Sifa 2016, 30 (6):  662-666.  Abstract ( 1159 )   Save The stability of Hujiapo landslide in the Three Gorges Reservation Area was performed by considering the pool level fluctuation and the precipitations. The progressive deformation of the slope induce by the pool level fluctuation was predicted. The landslide was simulated with three dimensional finite element analysis using MohrCoulomb constitutive model and tension failure criterion under the pool water level fluctuations and precipitation conditions. The extreme loading conditions were simulated in the numerical analysis. Related Articles | Metrics

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The Impact Study of Metro Construction Disturbance On Buildings Along The Metro XU Wenbo, YU Jian, WAN Zan 2016, 30 (6):  667-671.  Abstract ( 884 )   Save The building destress problems along the subway alignment due to the metro construction receive more and more attentions in recent years. The magnitude of the ground subsidence was quantified using Peck’s observational method and validated with the observed data for a site specific location. Using the settlement curve as the input, the three stories sing span and double spans frame structures were evaluated with a commercial software ANSYS. The cracking moment was used as an index in the structural safety evaluation. Therefore, the structural safety can be quantified with settlement magnitude. The site specific evaluation concluded that the building structures were safe under the input ground subsidence values. Related Articles | Metrics

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Review of Methods Predicting Tunnel Excavation Induced Ground Subsidence XIAN Jiaju, ZHANG Jianlong 2016, 30 (6):  672-676.  Abstract ( 948 )   Save The ground subsidence as well as the disturbance of soil around the large diameter pipe excavation might be induced by the pipe jacking construction. This paper provides a review of the development of the methods that predicting the ground subsidence and a review of the ground subsidence mechanism. The ground subsidence methods can be categorized as: empirical, theoretical, numerical and statistical from observed data. Current research topics and their solutions are also discussed in the paper. Related Articles | Metrics

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Classification and Coding of Deep Excavation Monitoring Information CHEN Cheng1, XU Bangshu1, CUI Yupeng1, ZHANG Haiping2, CUI Wei1 2016, 30 (6):  677-681.  Abstract ( 1060 )   Save Currently, the deep excavation monitored dada are not systematically catgorized and standardized, therefore, a large amount of monitored data are potentially wasted since the data cannot be shared. In order to form a standardized coding system for the deep excavation monitored data, the The current deep pit monitoring information has not form a certain standard yet, the data cannot be shared, which cause a lot of waste of monitoring data. In order to form a unified coding standard, on the basic of the current monitoring standards and the research of the previous, in the case of the monitoring data of Changzhutan railway Xiangfu road pit, the monitoring data has been classified, and the paper propose the standard of the monitoring classification and coding, utilizing the most advanced spatial geodatabase technology to manage the monitoring data and design of the database table. At last, based on the .NET framework and C# development language, and the ArcGIS Engine 10.2 is used as the development platform, the management system of the database is developed to achieve the information management of the monitoring data. Related Articles | Metrics

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Numerical Simulation of the Particle Breakage of Coarse Aggregates HE Yongrui 2016, 30 (6):  682-687.  Abstract ( 1086 )   Save The coarse aggregates could demonstrate a significant particle breakage characteristics under the external loading conditions and this particle breakage has a great influence on the mechanical properties of the coarse aggregates. In order to analysis the effect of particle breakage mechanism on macroscopic mechanical properties of coarse aggregate, and study the influence of different factors on particle breakage, the concept of “cluster” was introduced to simulate the characteristics of the particle breakage effect. Physical experiments and the corresponding numerical studies were performed in Gushui Rockfill Dam project. The particle breakage effect was verified with the PFC2D simulation software. The results indicate that, with the increase of axial stress, particle breakage gradually began to produce when the yield stress was reached. Then, the crushing rate had a sustained increase. The change of the contact stress is the main cause of the particle breakage. The confining pressure, particle shape, parameters can contribute some degrees of influence on the particle breakage. Related Articles | Metrics

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Study and Application of the Cement Stabilizer and its Corrosion Resistance Property ZHAO Yueqi 2016, 30 (6):  688-690.  Abstract ( 772 )   Save A grouting mix slurry with high sulfate resistant and retarding characteristics was specially developed for soils in a coastal area with high sulfate contents a complicated hydrological conditions. This grouting mix uses high sulfate resistant cement as a base matrix added with bentonite and bentonite, hydroxypropyl methyl cellulose, sodium hexametaphosphate as flyash in order to improve the stability, flowability, initial setting time as well as the sulfate resistance. The optimum mix design was obtained through the orthogonal experiments. Related Articles | Metrics

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Influence of Degree of Compaction on the Permeability and Shear Strength of Remolded Guilin Laterite Soils 2016, 30 (6):  691-695.  Abstract ( 1232 )   Save Laterite soil is a typical special soils and it is widely distributed in?Guilin area. In order to ensure the stability of laterite soil subgrade,?the remolded Guilin laterite soil samples under the optimum moisture content were prepared from the wet side and the permeability of the soil samples were tested with falling head method. An exponential reduction in the permeability magnitude with the increase of degree of compaction. Under triaxial test conditions, the tested cohesion value increases exponentially with the increase of degree of compaction. The internal friction angle, however, has a quadratic polynomial relationship with the degree of compaction: it increases and then reduces with the increase of the degree of compaction. The paper recommends the degree of compaction of Guilin laterite soil for the roadway subgrade should be greater than 94%. Related Articles | Metrics

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Mechanical Characteristic of Shallow Calcareous Sands from Coral Reefs LIU Jiang 2016, 30 (6):  696-698.  Abstract ( 1221 )   Save The shallow coral reefs are mainly deposited by the calcareous sands and gravels which somewhat special to the conventional geotechnical properties of quartz sands and gravels. The basic mechanical characteristics of the calcareous sands from the surficial part of a coral reef are investigated throughout the conventional consolidation tests and direct shear tests. The results indicate that the void ratios of the calcareous sand are much greater than sands from other origin. Under the increased confining pressures, the void ratios of the samples are slightly reduced with a magnitude less than 10%. A large compressibility of loose calcareous sands and the compression modulus increase with the sand deposition depth. Form a loose calcareous sand deposit in coral reefs, the unit weight usually increases with the depth; however, the shear strength of the calcareous sand is generally constant with depth. More test evident is necessary to verify that relationship between the density and shear strength. Related Articles | Metrics

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Impact of the Different Excavation Sequences for the Stability of Deep Excavation Adjacent to a Soil Covered Rock Slope XIONG Yifan 2016, 30 (6):  699-701.  Abstract ( 1032 )   Save The impact of different supporting systems for the deep excavation on the stability of an adjacent soil covered rock slope in Jingdezhen is presented in this paper. The stability of the slide resistant caisson with ground anchor supported deep excavation under four different excavation sequences was numerically evaluated. These four excavation sequences are: excavation at the entire site simultaneously; excavation area by area; excavation at alternate area; and excavation sequentially at alternate area. The movement at the soil covered slope were compared and it is concluded that the slide resistant caisson can effectively maintain the stability of the slope. It is also concluded that the excavation sequentially at alternate area method is more favorable to the slope stability. Related Articles | Metrics

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The optimization way of dual structure slope excavation under the complex environment conditions HUANG Wen, HU Yijie 2016, 30 (6):  702-704.  Abstract ( 1110 )   Save With the highspeed of the economic development, the urban construction is more and more concentrated.Highrise building foundation pit excavation is bound to be affected by the surrounding complex environment, therefore selecting the reasonable foundation pit excavation scheme has a higher request in the surrounding complex environment.Based on the case of the foundation pit excavation, this paper quantitatively analysis the reasonable slope excavation scheme with the cars dynamic loads around the binary structure.The stepbystep excavation and stepbystep jump dig methods are simulated by setting the model of slope excavation, and it is concluded that the most beneficial to maintain the stability of foundation pit excavation method is stepbystep jump dig. Related Articles | Metrics

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Overview of research on dynamic response of fiber-reinforced soil QIAN Yelin 1,2, GUO Panpan 2, WANG Jie 1, LV Weike 1, SHAN Shengbiao 2, WANG Yixian 2 2016, 30 (6):  705-713.  Abstract ( 1094 )   Save Soil reinforcement with randomly distributed discrete fibers is an efficient technology which can improve significantly the strength and deformation characteristics of soil subjected to static and dynamic loads. At present, existing studies are mainly concentrating on the responses of fiberreinforced soil to static load, while the behaviors of fiberreinforced soil under dynamic load are not well evaluated. Nevertheless, the dynamic responses of fiberreinforced soil are very important to the stability of engineering structures subjecting to various kinds of dynamic loads, such as earthquake, sea wave, machine vibration, etc. In this paper, the current situation of existing researches upon dynamic behavior of soil reinforced with randomly distributed fibers is reviewed, summarized, and evaluated, based on which, suggestions on the future research work for dynamic behavior of fiberreinforced soil are proposed, hoping for making a contribution to the subsequent researches and to better applying fiber reinforcement to geotechnical engineering. Related Articles | Metrics

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Physical and Mechanical Properties of Undisturbed Granite Residual Soils under High Stress CHEN Hongquan, CHEN Dingan, ZENG Zhiguo 2016, 30 (6):  714-717.  Abstract ( 906 )   Save The block undisturbed samples of colluvial residual soils from the granite parental bedrock were collected manually from the bottom of a proposed waste soil storage site. The undisturbed soil samples were performed for conventional consolidated drained and undrained direct shear tests, and consolidated undrained triaxial shear test under intermediate confining pressures. The moisture contents densities before and after the test as well as the stressstrain curves were monitored. The test results indicate that there are relationships exist among the confining pressure and sample density as well as moisture content. The statistic relationship between the shear strength parameters (cohesion and internal friction angle) and the confining pressures can be obtained. Based on the laboratory test results, the shear strength property (cohesion and internal friction angle) of the residual soils at different heights of overburden soils can be estimated from the unit weight, moisture as well as the proposed confining pressure. Related Articles | Metrics

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The Study of the Bearing Capacity of the Foundation Soils ZHAO Chong, LI Jian, TAI Jun 2016, 30 (6):  718-720.  Abstract ( 1131 )   Save In order to determine the bearing capacity of the foundation soils, different test methods were applied to different layers of soil strata in a train station of No. 3 Line of Suzhou Transit Project. The following testing methods were applied: laboratory testing of index and mechanical properties; pressuremeter tests; screw plate loading tests and cone penetration tests. The differences of the bearing capacity value obtained from different testing methods are compared. The results indicates that the bearing capacity values from these testing methods vary significantly. Usually, higher bearing capacity values can be obtained from laboratory test and cone penetration test; whereas, the bearing capacity values obtained from the pressuremeter test and screw plate loading test are more close the values used in the design. Related Articles | Metrics

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The Strength Properties of the Coarse Sand with Various Fine Sand Contents LI Jun, YANG Xueqiang 2016, 30 (6):  721-725.  Abstract ( 1025 )   Save Fine content is one of the main factors that affect the shear strength of the sand. A series of true triaxial shear tests of the fine sand mixed with various amounts coarse sand are conducted. Both the fine sand and coarse sand are selected form the Fujian standard sand. The sand mixtures are consolidated and drained tested confining pressures of 100kPa and 300kPa, respectively. The results show that the shear strength of the samples at the initial stage of shear is not quite different under both the low confining pressures and the high confining pressures. After a strain hardening process, both pure coarse sand and pure fine sand demonstrate a very high strength. But when the samples are the mixtures of coarse and fine sands, the fine particles at the edge of the coarse sand skeleton serve as a role of roller. The shear strength of coarsefine sand mixtures reduces with the increase amount of fine sand content. Related Articles | Metrics

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Impact of Freeze-Thaw Cycles on the Resilient Modulus of Silty Clay Soils LIU Fang, RAN Wuping 2016, 30 (6):  726-729.  Abstract ( 1009 )   Save The impact of moisture content, degree of compaction and freezethaw cycles on the resilient modulus of silty clay soils are extensively laboratory studied using silty clay soils from Urumqi. The sample preparation details, basic physical properties and relationship curves are obtained. The significance analysis of the test data were statistically analyzed using orthogonal method. The results indicate that the resilient modulus value of samples with the same soil type tend to be stable after 34 freeze thaw cycles. Among the three factors that might impact the resilient modulus, the sequences are: moisture contents, freezethaw cycles and degree of compaction. The moisture content is the largest impact factor and the degree of compact is the lowest. Related Articles | Metrics

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Influence of Freeze-Thaw Cycles on the Cohesion of a Silty Clay ZHANG Xiang, ZHAO Qun, WANG Hui, LI Xiaoquan 2016, 30 (6):  730-732.  Abstract ( 1158 )   Save The effect of the freeze and thaw cycles on the cohesion of a silty clay is studied throughout the triaxial shear tests. The test results indicate that the freezethaw cycles have strong influences on the cohesion of the silty clay tested. For samples that have a moisture content of 9% and degree of compaction of 90%, the cohesion reduction has the largest under the first cycles. With the increase of freezethaw cycles, the cohesion reduction magnitude is gradually reduced and the cohesion tends to be stable after 10 freezethaw cycles. Related Articles | Metrics

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Experimental Study of Shear Characters of Mucky Soils under Triaxial Impact Loading LAI Jiankun, GUO Lingfeng 2016, 30 (6):  733-736.  Abstract ( 922 )   Save The shear strength characters of mucky excessive soft soils were studied by using an improved true triaxial device SPAX200 under different a relative high impulse frequency (16Hz) with various confining pressures. The conclusions are presented in this paper: both the static and dynamic consolidation methods could have an obvious result of improving the soil shear strength. The results indicate that the soil samples with various impulse stress could have strength increase of 29%, 25% and 36%, respectively; 2) the strain softening effect was observed with intermediate or high confining pressures and the shear strength at the initial stage is higher than the samples under the conventional triaxial confining pressure. An optimum impulse frequency might exist for each sample under each overconsolidation ratio. Under this optimum impulse frequency, shear strength of the soil samples that under the same overconsolidation ratio can be improved throughout the dynamic and static consolidation action without strain softening effect. Related Articles | Metrics

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Influence of Moisture Content on the Parameters of Duncan-Chang Model of Chenzhou CoalBearing Soils YAN Yang 1,2, ZHANG Keneng 1,2, LIU Gaopeng 3 2016, 30 (6):  737-742.  Abstract ( 1141 )   Save The influence of moisture content on the parameters of Duncan-Chang Model of Chenzhou coal bearing soils was triaxial tested under consolidated undrained conditions. The typical remolded Xhenzhou coalbearing soil samples were prepared and tested with different moisture contents. Test results indicate that, failure pattern of all test samples were bulged and no obvious peak failure stress observed. The elastic deformations at the initial test stage were demonstrated and plastic deformations were appeared when the strain reached 3% ~5%. The influence of moisture content on parameters of Duncan-Chang Model parameters are different. The cohesion c is significantly affected by the moisture content. Values of parameters c, Ei, K and Kb decrease with the increase of moisture content, whereas, values of parameters of m, n, Rf increase with the increase of moisture content. The failure ratio Rf is greater than 0.9 when the moisture content of sample are within 15% -25%. The strain hardening characters are shown since no obvious shear failures were observed even if the Rf is greater than 0.9. Related Articles | Metrics