基于非稳定渗流理论的某土石坝坝肩岩体压水试验渗透系数确定方法  

Method for Determining Permeability Coefficient of Abutment Rock Mass Under Water Pressure Test of an Earth-rock Dam Based on Unsteady Seepage Theory

作　　者：袁博文 徐力群[2] 郭步天 聂柏松[2] 柴先墩 林文 YUAN Bowen;XU Liqun;GUO Butian;NIE Baisong;CHAI Xiandun;LIN Wen(Xinyang City Water Conservancy Bureau,Xinyang 464200.China;College of water Conservancy and Hydropower Engineering.Hohai Univ.,Nanjing 210098,China)

机构地区：[1]信阳市水利局,河南信阳464200 [2]河海大学水利水电学院,南京210098

出　　处：《三峡大学学报（自然科学版）》2022年第1期26-32,共7页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金/雅砻江联合基金项目(U1765205);国家重点研发计划(2019YFC1510802)。

摘　　要：不少水库工程地质条件复杂,岩体破碎、裂隙发育,透水性强,采用常规现场钻孔压水试验不能维持孔内压力稳定,因而不能采用规范推荐的计算方法获取岩体渗透系数.研究了采用非稳定渗流理论和有限元法反演分析技术,提出了钻孔压水试验非稳定渗流反演拟合法,通过拟合现场钻孔压水试验过程的非稳定渗流场,获取较为合理的岩体渗透系数.根据某工程实际情况,开展了现场钻孔压水试验,测得了坝址区岩体孔深8、12和16m的钻孔水位、流量随时间变化的关系.建立了各孔深条件下钻孔压水试验的三维有限元模型,应用非稳定渗流有限元法结合可变容差法,反演分析了各孔深试验的非稳定渗流场,得到了岩体的渗透系数.计算的渗透流量随时间变化过程与实际钻孔充水流量吻合良好,岩体的渗透系数符合实际情况.提出的钻孔压水试验非稳定渗流反演拟合法具有推广应用价值.The engineering geological conditions of many reservoirs are complex, the rock mass is broken, the fissure is developed, and the water permeability is strong. The conventional on-site drilling water pressure test cannot maintain the stability of the pressure in the borehole, so the calculation method recommended by the specification cannot be used to obtain the rock mass permeability coefficient. Based on the theory of unsteady seepage and the inversion analysis technology of finite element method, an inversion fitting method of unsteady seepage in borehole water pressure test was proposed. By fitting the unsteady seepage field in borehole water pressure test process, a reasonable permeability coefficient of rock mass was obtained. According to the actual situation of a project, the field borehole pressure test was carried out, and the relationship between borehole water level and flow rate with time was measured for rock mass borehole depths of 8 m 12 m and 16 m in the dam site area. The three-dimensional finite element model of borehole water pressure test under the condition of each hole depth was established, and the unsteady seepage field of each hole depth test was analyzed by using the unsteady seepage finite element method combined with the variable tolerance method, and the permeability coefficient of rock mass was obtained. The calculated process of seepage flow with time is in well agreement with the actual water filling flow of borehole, and the permeability coefficient of rock mass is in line with the actual situation. The proposed method of unsteady seepage inversion fitting for borehole water pressure test has the value of popularization and application.

关 键 词：压水试验 非稳定渗流 反演分析 渗透系数 

分 类 号：TU458[建筑科学—岩土工程]