层状盐岩储库夹层垮塌的理论分析

Theoretical Analysis of the Interlayer Collapse in Solution Mining of the Salt Cavern

盐岩矿床中难溶泥质夹层的存在给水溶造腔施工带来了诸多不利影响,如何科学有效地对夹层的垮塌进行预测成为造腔施工中亟待解决的难题。提出了夹层的两种简化力学模型,在圆柱形储库弹性理论解的基础上,应用弹性板壳理论对直接顶板夹层和悬空型夹层分别进行了求解;结合材料的强度破坏准则和整体失稳准则,得到了夹层发生强度及失稳破坏的具体判别式;分别使用推导的公式和数值软件对造腔结束后作用在夹层上的最大径向压应力和最大径向拉应力进行了计算,理论解与数值解的计算误差在0~5%以内。针对国内某盐岩储库地质条件,应用推导出的判别式对造腔过程中夹层的垮塌进行了计算和判断。算例结果表明：推导的方法对难溶夹层的垮塌预测具有较好的实用性。

The existence of insolvable interlayers in the salt deposit leads to many negative iniluences in the process of building salt cavern by solution mining, it is an urgent problem to find the solution of predicting the col- lapse of interlayers during the process of solution mining. Two simplified models of the interlayers are proposed and solved the problems with the help of elastic theory of plate and shell, standing on the theory resolution of cylinder storage cavern. Combined with the criterions of strength failure and overall unstability, the description of discrimi- nant is obtained to predict the collapse of interlayers. The maximum radial compressive stress and maximum radial tensile stress of the interlayers after the cavern building finished are calculated, respectively by using the numerical software and the proposed description of discriminant, the calculation error between theoretical and numerical re- suits is less than 5%. Based on the mechanics experimental data of salt rock and mudstone and the dimension pa- pameters of the interlayers from the salt cavern, using the discriminant to calculate and estimate the collapse of in- terlayers during the solution mining. The results indicate that the estimation is pratical to the prediction of collapse of interlayers.