应力对岩盐溶蚀机制的影响分析

ANALYSIS OF EFFECT OF STRESS ON DISSOLUTION MECHANISM OF SALT ROCK

结合地球化学、地质热力学、矿物岩石学、岩石弹塑性力学方面的知识,在理论上全面地分析应力对岩盐溶蚀机制的影响。研究结果表明,有无应力条件下岩盐的溶蚀机制在根本上是不同的,应力可在多个环节、多种方式面对岩盐的溶解产生影响,应力引起的应变能可以改变岩盐固体的物质活度、改变岩盐固体表面的生成物的浓度,直接对岩盐的溶蚀产生影响;应力还会通过改变岩盐外部溶液流态和水流速度u、固体表面边界层厚度h和有效水岩相互作用面积来间接地产生影响。应力作用下的岩盐溶解是一个"应力-溶解"耦合相互促进的正反馈循环;应力对溶解产生影响的内在关联在于应力引起的应变能会增大溶解反应的化学势能差,加速溶解反应,从而对岩盐的溶蚀产生影响。

Based on the theories of geochemistry,mineralogy,petrology,geo-thermodynamics,plastoelasticity,a comprehensive analysis of the effects of stress on dissolution mechanism of salt rock is carried out.And it reveals that stress has its effect at multi stages by many manners,and so the dissolution mechanism under stress is different from that without stress：（1） stress shows its influence directly by inducing additional free energy in the halite solid,which can increase the activity or concentration at the solid/liquid interface;（2） stress shows its indirect influences by changing the depth h of the bund layer at the surface of salt rock solid,velocity u and pattern of fluid water,and effective interaction area of dissolution between solid and water.It is found that the dissolution mechanism of salt rock under stress is a positive feedback loop owing to the coupling of stress-dissolution,and the essential relations between stress and dissolution are that strain energy can increase the chemical potential energy difference between water and solid at the solid/liquid interface,which can accelerate the reaction of dissolution progress and so shows its effects on the dissolution mechanism of salt rock.