直剪强度指标的可靠度统计方法

Reliability Method to Estimate Shear Strength Parameters

矩法和线性回归法能得到较为准确的岩土抗剪强度指标的均值,但是在统计标准差或变异系数时,矩法常常面临样本容量偏小而导致变异系数偏大的困难,而常规线性回归法无法给出实际所需的抗剪强度指标的标准差。本文从可靠度理论出发,利用正交标准化变量空间中原点到极限状态线最短距离为可靠指标的原理,提出了一种利用Excel"规划求解"功能求解抗剪强度参数的简便方法。将这一方法应用于91组404个水利水电岩土工程二类岩体与混凝土胶结面大型直剪试验结果的统计中,并将结果与其它方法进行了对比。

The moment method and linear regression method are main methods for estimating shear strength parameters of rock and soil.But the moment method is apt to overestimate the variation of strength parameters due to smaller sample size,and the conventional linear regression method cannot calculate the standard deviation to this paper,based on the reliability theory,a new method employed excel programming function is developed to estimate the shear strength parameters.The method is simplified by the principle that the shortest distance form origin point to limit state surface in the orthogonal normalization space is the reliability index.The results of 404 direct shear tests of the interface between second class rock mass and concrete from many large hydraulic projects are analyzed by the new method.The results from different methods are compared also.