衬砌-围岩完全光滑和常刚度滑移接触条件下压气储能洞室力学响应复变函数解

    Complex function solutions for mechanical response of compressed air energy storage caverns under full smooth contact and constant stiffness sliding contact conditions between lining and surrounding rock

    • 摘要: 针对非静水地应力场中压缩空气储能(CAES)洞室,本文基于复变函数理论和幂级数法建立了衬砌-围岩完全光滑接触与常刚度滑移接触条件下洞室力学响应解析计算方法。在力学解析过程中,引入位移释放系数η以考虑洞室施工时的支护延迟效应,并采用叠加法考虑了运行阶段的热应变作用。利用数值模拟验证了所提出的解析方法,并结合工程案例分析了不同影响因素下CAES洞室的应力分布与荷载传递规律。结果表明,衬砌-围岩接触条件对衬砌应力影响显著,但对围岩应力影响较小。相对于完全光滑接触,常刚度滑移接触时衬砌环向受拉区范围和拉应力量值均显著增大,而围岩环向拉应力略有降低。定义荷载传递比 为高内压作用下由衬砌向围岩传递的荷载占比, 随围岩与衬砌弹性模量比 增大而升高,随η增大而降低。增大 、减小η是提升围岩分担荷载比例、降低高内压引发衬砌环向拉应力的有效手段。降低衬砌-围岩界面滑移刚度可大幅降低衬砌内拉应力,而仅会引起小范围围岩拉应力小幅增加。

       

      Abstract: Based on the complex function theory and power series method, an analytical calculation method of mechanical responses for compressed air energy storage (CAES) caverns under non-hydrostatic ground stress fields are established under the full smooth contact and constant stiffness sliding contact conditions between lining and surrounding rock. A displacement release coefficient η is introduced to account for the support delay effect during cavern construction, and the superposition method is employed to consider the influence of thermal strain in the operational stage. Numerical simulations are conducted to validate the proposed analytical solutions, and the stress distribution and load transfer of CAES caverns under different influencing factors are analyzed with an engineering case study. Results show that the lining-surrounding rock contact condition exerts a significant influence on stress in lining, but has a relatively minor effect on stress in surrounding rock. Compared with full smooth contact, both the range of the circumferential tensile zone and the magnitude of tensile stress in the lining increase significantly under constant stiffness sliding contact, whereas the circumferential tensile stress in the surrounding rock decreases slightly. The load transfer ratio , defined as the proportion of the load transferred from lining to surrounding rock under high internal pressure, increases with the rise in the elastic modulus ratio of surrounding rock to lining, and decreases with the increase in η. Increasing and reducing η are effective approaches to enhance the load sharing ratio of the surrounding rock and mitigate the circumferential tensile stress in the lining induced by high internal pressure. Reducing the sliding stiffness at the lining-surrounding rock interface can substantially decrease the tensile stress within lining, with only a slight increase in the tensile stress of surrounding rock over a small zone.

       

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