岩石的复合型断裂实验及分析

EXPERIMENTS RESEARCH AND THEORETICAL ANALYSES IN BRITTLE FKACTUKE OF ROCK UNDER MIXED-MODE LOADS

当岩体内或边界上存在有Ⅰ－Ⅱ复合拉剪与压剪裂纹时（例如坝踵的裂纹），其临界载荷与初始开裂方向的确定是工程界十分关心的问题。本文用断裂力学理论，对大理岩进行了这方面较完整的实验与理论研究，且用四点弯试件实现了一定范围内的压剪断裂实验。研究结果表明，大理岩裂纹初始扩展所需的临界载荷值在很大程度上遵循最大拉应变ε＿（θｍａｘ）理论，而不是最大拉应力σ＿（θｍａｘ）理论，前者预示的载荷值远低于后者。两理论预示的初始开裂角相差不大，且与本文实验基本相符。

How to dertermine the critical load and initial propagation angle of a crack is a very important problem in engineering.A large number of Ⅰ-Ⅱ mixed mode fracture tests,including both tcnsion-shearingand compression-shearing tests, were conducted.Fracture critcrions are compared and analyzed based onthe experimental results.It is shown that the maximum strain theory is well supported by the experimentalresults of this paper.