钙芒硝盐岩蠕变特性的研究

 在自然界中，纯钙芒硝是以一种化合物的形式出现的，其分子式为Na2Ca(SO4)2，但在试件内部钙芒硝盐岩与泥岩互相混合，以混合物的形式出现，这就决定了其力学性质的特殊性。在不同的应力水平下，进行了长达100多天的单轴压缩蠕变试验，发现钙芒硝盐岩高应力水平蠕变速率高于低应力水平的蠕变速率，其蠕变速率在初期和后期比较大，并随时间大致呈U形分布，与NaCl岩盐相比，钙芒硝盐岩蠕变速率及蠕变量均较小。回归出钙芒硝盐岩在不同应力水平下蠕变应变随时间变化的曲线方程。对钙芒硝盐岩的蠕变模型进行初步探讨，通过对蠕变曲线与理论曲线的对比，说明同时包含弹黏塑性的西原模型能较好地反映钙芒硝盐岩的蠕变规律，并对相关参数进行了拟合。

STUDY ON CREEP PROPERTY OF GLAUBERITE SALT ROCK

In nature，the pure glauberite appears in the form of compound with structural formula of Na2Ca(SO4)2，but in the sample it appears in the form of mixture by glauberite and claystone internally，which determines that its mechanical and creep properties are different from those of general salt rock. Uniaxial compression creep test over 100 days is carried out under different stress levels. It is found that the creep velocity under high stress level is larger than that under low stress level，and the creep velocity and creep deformation are lower than those of general rock salt. By regressive analyses，the creep curve equations of glauberite salt rock under different stress levels are obtained，and creep constitutive relation of glauberite rock salt by comparing the creep curves with the theoretical curves is discussed. It is found that the Nishihara model containing viscoelasto plastic unit can better reflect the glauberite creep rule，and the correlation parameters are fitted as well.