岩石化学风化力学特性的宏微观定量关联

Macro-micro Quantitative Relations of Rock Mechanical Properties Considering Chemical Weathering

摘要:

为了分析化学风化对岩石力学性能的影响机制，采用密集排列的颗粒集合体模拟岩石材料，将与化学风化时间相关的质量损失率引入颗粒刚度和胶结模型。基于均匀化方法和格构模型，推导获得了风化岩石弹性阶段应力?应变关系和强度准则以及宏观弹性和强度参数与微观参数（颗粒接触响应特性、风化损伤参数等）的定量关联，并探究了化学风化及其时效性对岩石力学性能的影响规律。结果表明，随着质量损失率的增大以及反应时间的增加，风化岩石的刚度和强度均呈负指数减小；当环境pH值较低时，岩石的峰值黏聚力和峰值内摩擦角随着反应时间的增大均显著降低；当环境pH值较高时，开始阶段岩石的峰值黏聚力显著降低，而峰值内摩擦角变化不大，峰值内摩擦角的显著降低需要更长的风化时间。

Abstract:

In order to analyze the effect mechanics of chemical weathering on the mechanical properties of rock， in this paper， the densely packed particle assembly is used to simulate rock materials， and the mass loss rate related to chemical weathering time is introduced into the particle stiffness and contact model. Through the homogenization method and lattice model， the stress-strain relation in elastic stage， strength criterion and macro and micro quantitative relations of elastic and strength parameters with microscopic parameters （e.g.， inter-particle contact properties， weathering damage parameters） of rock are obtained， and the effects of chemical weathering and aging are investigated. The results show that with the increase of mass loss rate and erosion time， the stiffness and strength negative exponentially decrease. For the lower environmental pH value， both of the peak cohesion and peak internal friction angle decrease significantly with reaction time； while for the higher environmental pH value， the peak cohesion reduces significantly and the peak internal friction angle almost keeps constant in a short time， and more environmental time is needed for the decrease of peak internal friction angle.