摘要
从裂隙渗流的基本运动方程出发，反求岩体的渗透参数是工程控制论中一类典型的偏微分方程分布参数控制反问题，对于这类反问题常用数值法求解．考虑到结构面控水特点，依据岩体渗透系数张量与结构面产状的基本关系式，提出了一种结构面控制反演法．该方法不仅可以反算出岩体的渗透系数张量，而且可以反求出岩体控水结构面的当量渗透系数、渗透系数张量的主值和主方向，同时应用该方法计算的解具有较好的唯一性．以溪洛渡水电站工程为例介绍了这种数值反演方法在确定岩体渗透参数中的应用．
Permeability parameters of rock masses, such as hydraulic conductivity tensor, the equivalent permeablity coefficient of the discontinuities and the permeability coefficient of the discontinuities, are very improtant for solving the seepage problem in rock masses.Based on the partial equation of underground water flow in rock mass solving permeability parameters is a very typical inverse problem of distributed parameter systems of the partial equation in engineering cybernetics. It is a very effective means to determine the permeability parameters of medium by using numerical inverse analysis. Considering the characteristics of discontinuities in rock mass to control underground water flow and the basal connection between hydraulic conductivity tensor and discontinuity orientation in rock mass, this paper presented a discontinuities control inverse analytic method (DIAM). This method can not only solve the hydraulic conductivity tensor but also determine the equivalent permeability coefficient of the discontinuities, principal values and principal orientation of the hydraulic conductivity tensor in the rock mass. DIAM has the unique solution to determine the permeability parameters. The DIAM has two unique advantages: Firstly, the permeability coefficient of the discontinuities is obtained throught the DIAM.Moreover, the groups of the discontinuities that control underground water flow are generally three to four. And the hydraulic conductivity tensor has six independent components. So the numbers of unknown quantity can be cut down in the same zone. secondly, the orientation of the discontinuity that controls underground water flow in rock masses can be obtained trough field observation. And the every element in the matrix of the hydraulic conductivity tensor's experssion can be determined. So we can make good use of practical information of geological model, which can be transformed to physical model and mathematical model. The the results obtained from the DIAM are more reliable. As a case study, the DIAM is presented and applied to the inverse analysis for the permeability parameters in rock masses in the Xiluodu project. On the basis of analyzing geological and hydrogeological conditions of Xiluodu dam site, we take account of the characteristics of discontinuities in rock masses to control underground water flow and notice that flow field is under the influence of the groundwater basin. And then we take the difference between observation values and calculations of head as objective function. Conbined three dimensional finite element method with optimization, permeability coefficient of rock masses is obtained through inversion. As a result, it is effective to determine the hydraulic conductivity tensor of the complicated fracture rock masses and the karst media, the equivalent permeability coefficient of the discontinuities, principal values and principal orientation of the hydraulic conductivity tensor. It shows that not only the DIAM is simple and easy to apply, but also the calculated results are rational.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
1999年第3期316-322,共7页
Journal of Nanjing University（Natural Science）
基金
国家教委博士点基金
关键词
渗透参数
结构面
反演法
裂隙渗流
地下水
渗流
Permeability Parameters, Discontinuities, Inverse Analytic Method, Xiluodu Rock Masses
