Analysis of lining force transmission coefficient and surrounding rock displacement in lined rock caverns for underground gas storage

Abstract Lined rock caverns (LRCs) used for underground gas storage experience issues related to the deformation and stability of the surrounding rock under high internal pressures. This study applies the method of complex variable functions to obtain closed‐form solutions for the displacements of both the surrounding rock and lining. An explicit expression for the lining force transmission coefficient, which is defined as the ratio of the normal stress at the lining–surrounding rock interface to the internal pressure, is derived. Based on the calculation results, the lining thickness is preliminarily determined by the 0.1% tensile strain criterion of surrounding rock. The lining force transmission coefficient and maximum radial displacement of the surrounding rock are then analyzed for different rock mass grades and cavern sizes. The research results indicate that the lining force transmission coefficient is related to the displacement release coefficient (), lateral pressure coefficient (), ratio of in situ stress to internal pressure (), ratio of the lining's outer to inner radius (), ratio of the shear modulus of the surrounding rock to that of the lining (), Poisson's ratio of the surrounding rock (), and Poisson's ratio of the lining (). The research findings suggest that the lining force transmission coefficients for surrounding rocks of Grades I and II are minimally affected by changes in the internal pressure and in situ stress, and range from 0.94 to 0.98. Most of the internal pressure is borne by the surrounding rock, with the lining primarily serving to transfer the load, thus requiring a relatively small lining thickness. In contrast, the lining force transmission coefficients for surrounding rocks of Grades III and IV are significantly sensitive to changes in the internal pressure and in situ stress, with values ranging from 0.19 to 0.91. The lower the grade of the surrounding rock is, the smaller the proportion of load it can bear. In such cases, most of the internal pressure is borne by the lining, which consequently demands a larger lining thickness. The research findings provide a theoretical basis and guidance for engineering applications involving the design of LRCs in underground gas storage.