压气储能地下储气库围岩累积损伤特性数值研究

压气储能电站地下岩穴储气库围岩在循环运行工况下累积损伤效应明显。为研究大规模地下储气库围岩的累积损伤特性,基于损伤理论和FLAC^3D软件平台,二次开发了适用于大规模地下储气库循环加卸载条件下的累积损伤分析程序,并对程序正确性进行了验证。在此基础上,研究了储气库截面型式、洞室埋深和运行下限压力等因素对储气库围岩累积损伤特性的影响。研究表明:①储气库截面型式、洞室埋深和运行下限压力都对储气库围岩变形参数损伤影响较显著,且储气库竖直方向损伤深度都大于水平方向损伤深度;②损伤区内围岩变形参数的损伤程度和损伤变量随着洞室埋深或运行下限压力的增加而减小;③对于相同截面型式的储气库,埋深和运行下限压力不同时,储气库围岩损伤区内同一测点位置的损伤变量或变形参数差值随着循环次数的增加逐渐增大。大规模地下储气库围岩累积损伤特性对全面分析储气库的安全稳定性不可以忽略。

Numerical study on accumulative damage characteristics of underground rock caverns for compressed air energy storage

The accumulative damage effects in the surrounding rock of underground caverns for compressed air energy storage (CAES) are obvious in cyclic operation cases. In order to explore the cumulative damage characteristics of the surrounding rock of large-scale rock caverns, based on the damaged theory and FLAC^3D software platform, a routine is developed for the cumulative damaged analysis of the large-scale CAES rock caverns under periodically loading and unloading conditions and validated by a given example. On this basis, the influences of cross-section type of caverns, buried depth and the minimum operating pressure on the cumulative damage characteristics of the surrounding rock are analyzed. The results show that: (1) The cross-section type of cavern, buried depth and the minimum operating pressure are the factors significantly influencing the deformation analysis parameters of the surrounding rock, and the damaged depth in vertical direction is greater than that in horizontal direction. (2) The damage degree of deformation parameters and damage variables of the surrounding rock in damage zone decrease with the increase of the buried depth or the minimum operating pressure. (3) For the cavern with the same cross-section, the difference of damage variables and deformation parameters at the same location in the damage zone of the surrounding rock increases with the numbers of cycles both in the conditions of different burial depths and minimum operation pressures. The accumulative damage characteristics of the surrounding rock of large-scale underground caverns can not be ignored for comprehensive analysis of safety and stability of underground caverns for CAES.