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Huang J.,Beijing Jiaotong University | Huang J.,China Highway Planning and Design Institute HPDI Consultants Inc. | Zou P.,Water Resources University | Jiang X.,Water Resources University | Zhang D.,Beijing Jiaotong University
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University | Year: 2012

The depth-decaying hydraulic conductivity is a widely observed phenomen on and has a great control on groundwater flow. However, due to the limitations of testing method and the high cost, it is always difficult to establish the relationship between hydraulic conductivity and depth. Sonic velocity has been widely applied to obtain mechanical properties of rock masses. Due to its high resolution, it is practical to establish the relationship between sonic velocity and depth. In this paper, a granite rock mass is used as an example to analyze the relationship between mean p-wave sonic velocity and mean hydraulic conductivity at different depths. A power law model and a negative exponential model are employed to fit their relation. This study indicates that the sonic velocity is a useful method to obtain the depth-decaying hydraulic conductivity. Source

Su J.,Beijing Jiaotong University | Zhang D.,Beijing Jiaotong University | Gao Z.,Beijing Jiaotong University | Huang J.,Beijing Jiaotong University | And 2 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

Taking the construction engineering of the Zoo Station of Line 4 in Beijing Metro for example, the research was made on the deformation laws and its control measures of the station constructed by cut and cover reverse method. Structural deformation of the station during the construction process was simulated by Midas finite element method, and then the mechanical dynamic response of the stratum and structure in the whole construction process by cut and cover reverse method was divided into five "unloading-loading" phases. So, based on the deformation distribution method, "the whole process and stage control method" was put forward. In pre-construction stage, according to the stress characteristics and damage form of the station structure, structural differential settlement control standard values of the main construction stage were determined by back analysis. At the same time, king-pile static load and internal force test were carried out to make it have enough carrying capacity and non-deformability. During the construction stage, according to the stratum coordination excavation, structural coordination construction, the construction process was optimized. "Pile-sinking technology control" and "Grouting reinforcement" were synthetically used and the information monitoring and feed-back technology were adopted to realize station structural control. Actual monitoring results show that all construction stages differential settlement of Zoo Station has been controlled within the proper range to make the station structure safe and stable. Source

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