均质各向同性硬岩统一应变能强度准则的建立及验证

 在大量硬岩多轴加、卸荷强度试验成果分析基础上，研究硬岩强度及强度准则的基本特性，指出硬岩多轴加、卸荷强度均具有中间主应力效应、最小主应力效应、静水压力效应、应力Lode角效应和拉压异性效应。以强度准则的Zienkiewicz一般形式为基础，提出在Rankine型强度曲线和Drucker-Prager型强度曲线过渡的两参数表征的偏平面形函数，与有效应变能理论为基础的Wiebols-Cook强度准则的改进型子午面形函数相结合，建立均质各向同性硬岩统一应变能强度准则。大量硬岩加、卸荷试验数据验证了该强度准则能客观地反映各向同性硬岩强度基本特性和硬岩强度的非线性特征。通过参数调整，提出的统一强度准则将大量现有强度准则统一到同一强度理论框架下，极大地方便了强度理论的数值实现，适用于多种各向同性硬质岩类，进一步丰富了统一强度理论研究成果。

ESTABLISHMENT OF UNIFIED STRAIN ENERGY STRENGTH CRITERION OF HOMOGENEOUS AND ISOTROPIC HARD ROCKS AND ITS VALIDATION

The basic characteristics of strength and strength criterion of hard rock are studied based on the analysis of the results of multiaxial loading and unloading tests of hard rock；it is shown that the multiaxial loading and unloading strengths of hard rock have intermediate principal stress effect，minimum principal stress effect，hydrostatic pressure，stress Lode angle effect and difference effect under tension and compression. This paper presents a deviatoric plane shape function，characterized by two parameters transiting between Rankine type strength curve and Drucker-Prager type strength curve. Combined with modified meridian plane shape function of Wiebols-Cook strength criterion based on effective strain energy，an isotropic unified strength criterion of hard rock is constituted. Many loading and unloading test data of hard rocks have validated that the strength criterion can reflect objectively the basic characteristics of the strength of isotropic hard rock and the nonlinear characteristics of hard rock strength. Through parameter adjustment，the unified strain energy strength criterion presented in this paper unified many current strength criteria to one strength theory，which makes the numerical realization of strength theory more convenient. The unified strain energy strength criterion is applicable for various isotropic hard rocks，so as to further enrich the research achievements of unified strength theory.