三种强度准则的盐穴应力弹塑性解及参数敏感性分析

Stress elastic-plastic solution for salt cavern based on three strength criteria and its parameters sensitivity analysis

为了更安全地建造地下盐穴储气库,采用Hoek-Brown(H-B),Mohr-Coulomb(M-C)及Drucker-Prager(D-P) 3种强度准则,推导了在内压作用下盐穴的塑性区应力解及塑性半径,讨论了各准则对塑性区半径的影响规律及各准则参数的估计方法。分别运用单因素分析法及多因素分析法,分析了塑性半径对H-B准则参数的敏感性。研究结果表明:同等条件下,H-B准则受岩性、造腔等因素影响时,微小内压的波动使得塑性半径的变化更剧烈,岩体质量较差时更显著。盐穴塑性应力与M-C,D-P相比偏小,更接近实际工程状况。围岩塑性半径受H-B准则参数影响程度的大小依次为:GSI,m_i,σ_(ci),D。各参数的互相关性对结果影响不大。其中,H-B准则参数GSI,m_i,σ_(ci)的增大会使塑性半径减小,参数D的增大使得塑性区半径增大。研究成果可为合理选择盐穴储库硐室的力学模型及优化参数提供参考价值。

In order to construct the underground salt cavern gas storage more safely,three plastic strength criteria,HoekBrown( H-B),Mohr-Coulomb( M-C) and Drucker-Prager( D-P) are used to derive the stress solution and plastic radius of the plastic zone of the salt cavern under internal pressure. The influence law of each criteria on the radius of plastic zone are studied and the estimation method of each criterion parameter are discussed. The sensitivity of plastic radius to H-B parameters is analysed by using single factor analysis and multi-factor analysis. The results show that under the same conditions,when H-B criterion is affected by lithology,cavity formation and other factors,the fluctuation of the micro internal pressure makes the plastic radius change more severe,and the rock mass is more significant. The plastic stress of salt caves is smaller than that of M-C and D-P,which is closer to the actual engineering conditions The influence degree of the plastic radius of the surrounding rock by the H-B criterion parameters is: GSI,mi,σci,D,while cross-correlation of each parameter has little influence on the results. Among them,the increase of the H-B criterion parameter GSI,mi or σciwill decrease the plastic radius,and the increase of the parameter D will increase the radius of the plastic zone.,mi or σci,while it increases with the increase of The research results can provide reference value for the rational selection of the mechanical model and optimization parameters of the salt cavern storage chamber.