含夹层盐岩圆柱形储库力学特性的理论解析

THEORETICAL ANALYSIS OF MECHANICS BEHAVIOR OF CYLINDER STORAGE CAVERN IN ROCK SALT CONTAINING INTERLAYER

地下盐岩储库腔体一般采用水溶建腔方法,溶腔的径高比很小,可简化为圆柱形。截取储库中间部分为研究对象。结合我国盐岩矿含夹层的特点,通过接触面上不同岩层相对滑移与实际状态相等的方法,建立考虑夹层影响的力学特性等效计算模型。即先假定岩层与夹层接触面之间光滑,采用厚壁圆筒弹性解进行计算,再通过增减局部内压的方法使岩盐层和夹层间相对滑动与实际状态等效,推导出夹层附近储库围岩的应力分布函数。在存在夹层条件下,对储库力学特性进行数值分析。结果表明,考虑夹层影响的解析解与数值模拟计算的应力分布规律基本一致,其中腔壁上径向应力r误差最大为6.8%,环向应力最大误差为2.7%,满足储库设计分析要求。

Salt caverns are created by the method that circulating fresh water into the salt formation to dissolve the salt,so the cavern s ratio of radius to height is small and the cavern can be simplified into a hollow cylinder.The intermediate zone of the cavern was sectioned to take as research object.Considering the fact that the salt deposit in China is characterized by more interlayer,an equivalent calculation model was established to discuss the stress distribution function near the layer,based on the method of equivalent relative displacement on contact surface between rock salt and interlayer and actual state.Where assuming the contact surface is smooth,and thus the elasticity solutions of the thick-walled cylinder could be used to calculate stress distribution,then local internal pressure near the interlayer are increased and decreased to adjust the relative displacement until equivalent to actual state.The contrast between the numerical simulation and analytic solution shows that two results on stress distribution considering effect of interlayer is basically the same,in which maximum error of radial stress r and circumferential stress on cavity surface are less than 6.8% and 2.7% respectively.The analytic result meets require of storage cavern design analysis.