动水压力作用下碳酸盐岩溶蚀作用模拟实验研究

为研究岩溶地区水库蓄水不同条件下动水压力驱动下的碳酸盐岩溶蚀作用机制。以乌江流域某水电站坝前地区碳酸盐岩为研究对象，利用自行研制的开放体系压力溶蚀实验系统，对不同动水压力（0～2.0 MPa）条件下CO2水溶液溶蚀碳酸盐岩的过程进行实验模拟，其结果显示，动水压力增大会引起碳酸盐岩的溶蚀作用加剧，溶解速率曲线随动水压力的变化而发生显著改变；随动水压力的增大，岩石的化学溶解量和机械破坏量同时增大，两者的比值随着压力增大逐渐趋于1：1，两者之间存在耦合关系。采用扫描电镜与压汞试验相结合的方法进行微观研究发现，动水压力对碳酸盐岩的溶蚀作用不仅发生于岩石表面，使表面溶孔增大并加深，产生次生孔隙和次生矿物，同时还改变着岩石的内部孔隙结构，降低其渗透性并弱化结构面的连接。

Study of simulation experiment for carbonate rocks dissolution under hydrodynamic pressure

For studying dissolution mechanism conditions of carbonate rocks driven by hydrodynamic pressure in different storage periods, the carbonate rocks in a hydropower station at Wujiang River was selected as a research object; and the simulation experiments by using self-developed pressure corrosion equipment in open system was proceeded which showed that with the hydrodynamic pressure rising (from 0 to 2.0 MPa), the dissolution rate of carbonate rocks are increased. The curve of dissolution rate is obviously changed. During the dissolution of the carbonate rocks, with the water pressure increasing, the chemical dissolution and the mechanism damage obviously as changing as the hydrodynamic increasing, the ratio tends to 1:1. The results show that there is a coupling relationship. Microcosmic research based on scanning electron microscope and mercury injection test, the dissolution not only affects on the surface of the rock produce secondary pore and secondary mineral, but also influences the inner pore structure, decreases the permeability and connection among the structural planes of rocks.