白鹤滩水电站错动带非线性渗透参数的原位试验确定  

Determination of nonlinear permeability parameters for shear zones in Baihetan Hydropower Station by in-situ tests

作　　者：周志芳[1] 李思佳 王哲 郭巧娜[1] 石安池[2] 陈朦 沈琪 ZHOU Zhi-fang;LI Si-jia;WANG Zhe;GUO Qiao-na;SHI An-chi;CHEN Meng;SHEN Qi(School of Earth Science and Engineering,Hohai University,Nanjing 211100,China;East China Institute of Survey and Design,Hangzhou 311122,China)

机构地区：[1]河海大学地球科学与工程学院,江苏南京211100 [2]华东勘测设计研究院,浙江杭州311122

出　　处：《岩土工程学报》2020年第3期430-437,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金重大研究计划项目(91747204)。

摘　　要：基于广义非线性渗透的Forchheimer方程,提出了一种确定错动带非线性流渗透参数的原位试验方法。结合白鹤滩水电工程现场试验研究发现,非线性系数b、m的取值与稳定性和错动带的充填物类型、结构有关。C3、C4层间错动带m=2,非线性系数b值相对较为稳定,变化不大。C2层间错动带m=0.5,非线性系数b值相对稳定,但量级上远小于C3、C4层间错动带非线性系数b值;分析其原因认为高压压水试验过程中原来错动带连通性较差的孔隙,在高压水作用下形成了贯通的优势流通道,导致相同压力下的压水量大幅增加。依据试验获得非线性系数和非线性程度影响系数β判别,高压压水试验过程中压水孔和测试孔之间非线性项占绝对优势,地下水的运动状态均为非线性流,说明原位测试方法选择的压水孔和测试孔之间的距离、压力梯级变化是合适的。试验验证表明,错动带非线性渗透参数的原位试验方法不仅理论严密,而且具有试验过程简单、易操作,获取的参数齐全、精度高等优点,因此有很好的推广应用价值。Based on the Forchheimer equation of generalized nonlinear permeability, an in-situ test method for determining the permeability parameters of nonlinear flow in shear zones is proposed. Based on the field tests of Baihetan Hydropower Station, it is found that the values and stability of nonlinear coefficient b and m are related to the filling type and structure of the shear zone. In interlaminar shear zones of C3 and C4, m=2, and the value of nonlinear coefficient b is relatively stable with little change. In interlaminar shear zone of C2, m=0.5, the value of nonlinear coefficient b is relatively stable, but the order of magnitude is much smaller than that of interlaminar shear zones of C3 and C4. The reason is that the original pore with poor connectivity of shear zone forms a dominant flow channel under the action of high-pressure water, resulting in significant increase of water volume under the same pressure. Using the nonlinear coefficients obtained from experiments into Forchheimer equation for curves and judged by calculation of influence coefficient β of nonlinearity degree, the nonlinear terms between pressure holes and test holes are absolutely dominant in the process of high-pressure water tests. The movement state of groundwater is nonlinear flow. It is shown that the distance between pressure holes and test holes and the pressure gradient change selected by the in-situ test method are suitable. The test results show that the in-situ test method of nonlinear permeability parameters of shear zones is rigorous in theory and has the advantages of simple test process, easy operation, complete parameters and high accuracy, so it has good application value.

关 键 词：非线性流 渗透参数 白鹤滩水电站 原位试验 错动带 

分 类 号：TU433[建筑科学—岩土工程]