和理论分析
(1. 东北大学 资源与土木工程学院,沈阳 110004;
2. 河南理工大学 能源科学与工程学院,焦作 454000)
摘 要: 用岩石破裂过程分析软件(RFPA2D),采用与常用的Kaiser效应测原岩应力过程相似的加载路径,对岩石试样进行数值模拟实验。基于统计损伤力学理论,对Kaiser效应的机理进行分析,并在理论上验证数值实验的结果。结果表明:Kaiser效应的本质是对岩石内部损伤程度的记忆,传统用Kaiser效应测原岩应力的方法测得的应力值往往比真实值要小,而且,岩样在原岩中受到的侧向应力越大,用该方法测得的轴向应力值与真实值相差越大。因此,要得到准确的原岩应力,必须根据岩石的损伤本构关系对单轴加载测得的Kaiser效应点应力值进行校正。
关键字: 原岩应力;数值模拟;Kaiser 效应;损伤
estimating in-situ stress by Kaiser effect
(1. School of Resource and Civil Engineering, Northeastern University, Shenyang 110004, China;
2. School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454100, China)
Abstract:Numerical test was carried out by using software of Rock Failure Process Analysis (RFPA2D) to simulate the stress that the rock specimens were suffered in the process of estimating the in-situ stress by Kaiser effect. Based on statistical damage mechanics theory, the mechanism of Kaiser effect was analyzed, and the numerical test result was verified by rock strength theory. The results show that the mechanism of Kaiser effect is the memorizing ability of damage level in rock. The traditional method of estimating in-situ stress by Kaiser effect is not appropriate, for the result is usually smaller than real value, furthermore, greater confining compression that the specimen suffered in the rock mass would result in greater difference between the Kaiser effect stress acquired from uniaxial loading in laboratory and real level of in-situ stress. Consequently, to estimate the in-situ stress more accurately, the adjustment based on the damage constitutive relation must be done to the Kaiser effect stress value acquired from uniaxial loading.
Key words: in-situ stress; numerical simulation; Kaiser effect; damage