石灰岩损伤演化的化学热力学及动力学模型

隧道开挖排水后 ,地下水动力学及化学环境的改变可能使石灰岩围岩化学损伤的演进过程加速 ,为定量化评价此作用 ,引入了化学热力学和化学动力学的理论和方法 .建立化学热力学模型 ,通过吉布斯自由能变化判定隧道水化学损伤能否自发进行 ,为在工程中是否需要考虑化学损伤及进行损伤场的计算提供依据 .将轻微改造后的裂隙概化为平行板模型 ,采用Plummer Wigley Parkhurst方程建立定量评价化学损伤的化学动力学模型 .根据实际情况取定化学反应的阶数 ,通过质量守恒定律计算出裂纹在迹长及隙宽方向的变化 ,得到化学损伤定量演化的公式 .

Chemical Thermodynamic and Chemical Kinetic Model for Dissolution Damage Evolution in Limestone

After the excavation and drainage of groundwater,the evolution course of dissolution damage crack system of limestone may be accelerated because of the alteration of hydraulic and hydrochemical environment.To evaluate the course in quantity,the theories and methods of hydro-chemical thermodynamic and hydrochemical kinetic are introduced.Establishing hydrochemical thermodynamic model,whether the evolution will be accelerated can be determined by calculation in quantity,which will provide basis for the decisions whether considering the acceleration's affect to a tunnel.The slightly rebuilt damage crack system of limestone can be summarized as a system of parallel boards,and a simplified Plummer-Wigley-Parkhurst equation is introduced to establish the hydrochemical kinetic model.According to the hydro-chemical kinetic model and quality conversation law,the evolution equation of damage in limestone surrounding rock is obtained,which will provide theoretic support for the study of evolution of hydrochemical-hydraulic coupled damage under tensile and shear stresses.