Global stability analytical method of cavern group in salt rock based on energy criterion

摘要

In order to assess the global stability of underground cavern group for energy reserves, deformation stability theory which considers the strength reduction approach of finite element method (FEM) is developed. Global stability criterion of cavern group is established based on the K～u0001E relation, where K is the strength reduction factor and u0001E is the plastic complementary energy. For the state of instability, the unbalanced forces clearly exhibit the position and pattern of the local failure.We study the global stability and local failure of the single cavern, double cavern, multi-cavern and Jintan oil and gas storage cavern group in salt deposit. Multiple influencing factors such as cavern diameter, cavern spacing, weak intercalation, internal pressure, pressure loss and cavern layout were considered. As a result, the maximum cavern diameter, the minimum cavern spacing, the minimum stable internal pressure and the optimal layout mode of cavern group was determined.