考虑空间效应的地下洞室爆破开挖松动区参数场位移反分析

Displacement back analysis of parameter field of blasting excavation damaged zone around openings considering spatial effect

将地下洞室爆破开挖松动区视为一个随开挖过程演变的非均匀、非稳定三维扰动场,松动区内岩体力学参数则是一个具有时空演化特性的参数场。考虑爆破开挖扰动空间效应和岩体真实变形响应,提出了真实工作状态下开挖松动区岩体参数场辨识的位移反分析方法。基于局部监测变形空间插补得到的空间位移场,通过分析洞室爆破开挖围岩变形扰动机制,建立了开挖松动区岩体变形模量参数场数值演化模型,并进行了模型适用性和参数敏感性分析。在此基础上,以变形模量参数为例,结合围岩实测位移信息,提出了开挖松动区参数场位移反分析的动态实现过程。将该方法应用于溪洛渡地下洞室群施工期参数场反演和围岩稳定动态反馈评价及预测,结果表明,该方法合理有效,在大型地下洞群施工开挖与快速监测反馈方面具有显著的工程适用性及实用性。

Blasting excavation damaged zone（EDZ） is regarded as a heterogeneous and unsteady three-dimensional disturbed field evolving with the excavation progress;and the mechanical parameters in EDZ are identified as a parameter field of time-space evolution characteristics.A displacement back analysis method is proposed for parameter field identification of the EDZ around openings in practical working state,considering the spatial effect of blasting disturbance and real deformation response of rock mass.Based on the spatial displacement field obtained by space interpolation of local monitoring displacements,by analyzing the deformation disturbance mechanism of the surrounding rock,a numerical model for parameter field of rock mass deformation modulus in EDZ is put forward;and the applicability and parameters sensibility are further analyzed.Taking the deformation modulus for instance and combining the measured displacement of surrounding rock,the dynamic implementation progress of the displacement back analysis for parameter field is introduced in detail.Finally,the method is applied to the parameter field identification and dynamic feedback analysis and prediction of stability assessment of the surrounding rock during construction of Xiluodu underground caverns.It is shown that the method is reasonable and effective and of significant engineering applicability and practicality for fast feedback analysis of monitoring and stability assessment during construction of large-scale underground caverns.