干湿循环作用下泥质白云岩能量机制试验研究

为研究干湿循环作用下泥质白云岩力学特性和能量机制，利用MTS851.03岩石力学试验系统分别对干湿循环0次、40次及60次试样进行三轴压缩试验，分析了3种状态下泥质白云岩损伤破坏过程中的能量演化规律，并以可释放弹性应变能为统计分布变量，基于Weibull分布建立泥质白云岩的损伤统计本构模型。结果表明：3种状态下试样峰值强度与围压的回归关系符合主应力表达的Mohr-Coulomb准则特征；泥质白云岩试样能量实时演化过程具有阶段性；干湿循环作用使泥质白云岩的内部损伤和塑性变形加强；峰值点处试样各应变能随围压线性增大，储能极限随干湿循环次数逐步减小；以可释放弹性应变能为统计分布变量建立的损伤统计本构模型能较好模拟试样三维条件下的应力-应变关系。

Experimental Study on Energy Mechanism of Argillaceous Dolomite under Cyclic Wetting and Drying

In order to study the mechanical properties and energy mechanism of argillaceous dolomite under the action of dry and wet cycles, the MTS851.03 rock mechanics test system was used to perform triaxial compression tests on samples of 0, 40 and 60 dry and wet cycles, and analyzed three types The energy evolution law during the damage and failure process of argillaceous dolomite in the state, and the releasable elastic strain energy is used as the statistical distribution variable, and the damage statistical constitutive model of argillaceous dolomite is established based on the Weibull distribution. The results show that the regression relationship between the peak strength of the sample and the confining pressure in the three states conforms to the characteristics of the Mohr-Coulomb criterion expressed by the principal stress; the real-time evolution process of the energy of the argillaceous dolomite sample has phases; the dry-wet cycle makes the argillaceous dolomite. The internal damage and plastic deformation of the rock are strengthened; the strain energy of the sample at the peak point increases linearly with the confining pressure, and the energy storage limit gradually decreases with the number of dry and wet cycles; the damage statistics established with the releasable elastic strain energy as the statistical distribution variable. The constitutive model can simulate the stress-strain relationship of the specimen under three-dimensional conditions.