围压对花岗岩强度特性与脆性的影响及其表征  

Influence of Confining Pressure on Strength Characteristics and Brittleness of Granite and Its Characterization

作　　者：李艳[1] 杨宇冰 梁文彪 翟越[1] 魏盛宇 Li Yan;Yang Yubing;Liang Wenbiao;Zhai Yue;Wei Shengyu(School of Geological Engineering and Geomatics,Chang an University,Xi'an 710061,P.R.China;School of Sciences,Chang an University,Xi'an 710061,P.R.China)

机构地区：[1]长安大学地质工程与测绘学院,西安710061 [2]长安大学理学院,西安710061

出　　处：《地下空间与工程学报》2024年第5期1528-1540,共13页Chinese Journal of Underground Space and Engineering

基　　金：陕西省博士后自然科学基金(2023BSHEDZZ211);咸阳市科技创新团队项目(L2023CXNLCXTD005);中央高校创新团队项目(300102262402)。

摘　　要：围压是影响岩石力学属性的主要因素之一。为了研究围压效应对花岗岩强度特性和脆性特征的影响效应及机理,以色季拉山花岗岩为研究对象,开展不同围压工况的室内三轴压缩试验,得到破坏形态、峰值应力等强度参数的变化规律,并在统一强度理论框架内构建考虑围压效应的三轴本构模型。基于全应力应变曲线建立采用断裂能表征的岩石脆性评价指标,确定围压与岩石脆性的定量关系。在此基础上,采用RPFA软件模拟花岗岩在不同围压下的破坏全过程及声发射演化特性,揭示花岗岩的损伤演化机制。结果表明:围压可有效限制花岗岩内部细观裂纹的产生和扩展,进而显著提高花岗岩的宏观强度及变形性能;本文建立的三轴本构模型和脆性评价指标可有效反映围压效应对岩石强度特性和脆性的影响规律。Confining pressure is one of the main factors affecting rock mechanical properties.In order to study the effect and mechanism of confining pressure effect on the strength and brittleness characteristics of granite,this paper takes Sejilashan granite as the research object,carries out indoor triaxial compression tests under different confining pressure conditions,obtains the variation rule of strength parameters such as failure form and peak stress,and constructs a triaxial constitutive model considering the confining pressure effect within the framework of unified strength theory.Based on the total stress-strain curve,an evaluation index of rock brittleness characterized by fracture energy was established to determine the quantitative relationship between confining pressure and rock brittleness.On this basis,RPFA software is used to simulate the whole process of failure and acoustic emission evolution characteristics of granite under different confining pressures,so as to reveal the damage evolution mechanism of granite.The results show that the confining pressure can effectively limit the formation and propagation of microcracks in granite,and then significantly improve the macroscopic strength and deformation properties of granite.The triaxial constitutive model and brittleness evaluation index established in this paper can effectively reflect the law of confining pressure effect on rock strength characteristics and brittleness.

关 键 词：花岗岩 围压效应 强度特性 岩石脆性 损伤演化机制 

分 类 号：TU45[建筑科学—岩土工程]