大柳树水利枢纽坝区渗流场与应力场耦合分析

ANALYSIS OF COUPLED SEEPAGE AND STRESS FIELDS IN ROCK MASS AROUND THE DALIUSHU DAM

黄河大柳树水利枢纽坝区岩体大范围发生了松动,确定其渗透特性指标并进行渗流场与应力场耦合分析具有重要的现实意义。首先,根据坝区两岸平硐内测量的优势节理裂隙组资料和左岸固结灌浆试验资料,综合确定坝区岩体初始渗透系数张量;然后,应用多重裂隙网络模型,进行3个重要断面的渗流场与应力场耦合分析。可以看出,坝区工程范围内岩体渗透性很强,初始渗透系数张量量级达10^(-5)～10^(-4)m/s;绕坝渗流的两个断面(A-A,B-B)主要是渗流损失问题,通过坝基渗流的断面(C-C)在坝踵处出现了应力集中现象。

It is of practical value to determine the permeability of large-scale loose rock mass around the Daliushu dam on the Yellow River and to analyze the coupled seepage and stress fields. The permeability coefficient tensors of rock mass are calculated by the data of the dominant sets of joints or fractures and their distribution parameters statistically obtained from the many prospecting tunnels, and modified by the data of consolidation grouting test (including water pressuring test) in the left abutment. The analysis of coupled seepage and stress fields within three main sections are also carried out by means of the multiple-level fracture network model. It can be concluded that rock mass around the dam has great permeability with the magnitude of 10^(-5)—l0^(-4)m/s, and that the seepage discharge along section A-A and B-B should be large, the stress concentration occurs around the dam heel in section C-C.