钙芒硝盐岩溶解渗透力学特性研究

溶解是盐类矿物的基本特性，渗透是流体在溶质浓度梯度、压力梯度及二者共同作用下经过多孔介质的运动。由于矿物组分溶解特性的差异，在一定渗透压力作用下，钙芒硝盐岩体内会产生溶解渗透交互促进作用，从而由低渗透介质变为高渗透的多孔介质，其渗透及力学特性受其矿物组分硫酸钠溶解程度的影响极大，这种特性称之为溶解渗透力学特性。实验结果表明，钙芒硝盐岩的渗透率为溶解渗透时间及渗透压的函数。在围压为2.0MPa、初始渗透压为1．0MPa的溶解渗透作用下，获得不同溶解渗透时间时渗透率与渗透压的关系。由于溶解渗透使得矿物组成及其结构的变化，钙芒硝盐岩在溶解渗透前后三轴力学特性差异也很大，在2．0MPa围压的作用条件下，溶解渗透49h之后，钙芒硝盐岩的强度由未溶解渗透时的46．53MPa，降低为溶解渗透后的11．42MPa：与此同时，弹性模量也由43．700MPa降低为0．834MPa。因此，溶解渗透对钙芒硝盐岩的力学特性有着极大的影响。

INVESTIGATION ON SOLUTION PERVASION AND MECHANICAL CHARACTERISTICS OF GLAUBERITE SALT ROCK

Solution is an essential character for salt rocks. Pervasion is a liquid movement through porous media under the actions of solute concentration gradients, pressure gradients, or the both. As the difference of solution characters for different mineral components in calcium thenardite, the solution and pervasion mutual actions can be found in the calcium thenardite rock salt body under the action of certain osmotic pressure. Thus the calcium thenardite becomes penetrable porous medium, holding the pervasion and mechanical characteristics that are called solution pervasion and mechanical characteristics, respectively. It is greatly affected by the solubility of sodium sulfate, and one of the components is calcium thenardite. Experiments illustrate that the permeability is the function of solution time and osmotic pressure of calcium thenardite salt rock. Meanwhile, the three-dimensional mechanical characteristics of calcium thenardite salt rock take great changes after a period of solution pervasion actions. The compression strength of calcium thenardite rock salt changes from 46.53 MPa to 11.42 MPa after 49 h solution pervasion with 2.0 MPa confining pressure. Accordingly, the elastic modulus changes from 43.700 MPa to 0.834 MPa. So, it can be concluded that solution pervasion has great effect on mechanical characteristics of calcium thenardite rock salt.