应用蒙特卡洛法确定节理岩体的连通率和综合抗剪强度指标

本文提出了一种确定节理岩体连通率和岩体综合抗剪强度指标的新方法。该方法对传统的连通率的概念作了扩充,将连通率的确定归结为在岩体结构面网络图中寻找节理面和岩桥组合破坏路径的问题。在连通率的确定过程中,考虑了节理和岩桥的组合破坏机制。并应用动态规划原理,基本解决了岩体中存在多组节理面情况下的连通率确定问题,所得成果在漫湾电站左岸边坡稳定分析研究中获得了成功的应用。

DETERMINATION OF JOINT PERSISTENCE AND SHEAR STRENGTH PARAMETERS OF ROCK MASSES BY MONTE CARLO METHOD

Rock masses usually contain a number of joint sets. The shear strength of a jointed rock mass therefore depends not only on the discontinuity, but also on the rock bridge which is defined as the intact rock between two joints. An approach for evaluating the shear strength based on a rational determination of the joint persistence ratio k is presented in this paper. It includes four steps. (1) Find the probability distribution functions and associated statistical parameters of the joints geometry, including the dip, dip angle,spacing and trace length, based on the geological data collected in the field scanline survey. (2) Create a simulated rock joint network by the Monte Carlo method based on the above-mentioned statistical characteristics. (3) Caculate the k value in a certain direction of shear on the joint network by dynamic programming. The approaches of determining the shear strength of a joint given by Barton and shear strength of a rock bridge given by Lajtai are employed. (4) Caculate the shear strength of a rock mass a]ong that specific direction of shear based on the obtained k value. The approach has been successfully used in evaluating the k value and shear strength of jointed rock masses of the Manwan Hydropower development project.