基于4D-LSM的隧道围岩爆破振动和损伤判定研究

Numerical modeling of vibration and damage of surrounding rock in tunnel blasting by using 4D-LSM

针对四维晶格弹簧模型(four-dimensional lattice spring model,4D-LSM)在岩石爆破中的应用进行研究,介绍4D-LSM在隧道围岩爆破方面的基本要素,包括动力学方程、无反射边界条件以及基于多体破坏准则的岩石破坏模型等。针对隧道围岩爆破问题,采用4D-LSM建立隧道爆破围岩振动分析模型、单炮孔爆破模型以及围岩损伤模型等。在不同隧道爆破设计方案的基础上,通过几何简化和边界条件简化处理这些模型实现对给定爆破方案的隧道爆破围岩关键点峰值荷载速度的量化分析。针对单孔自由面爆破问题,对比离散晶格弹簧模型(distinct lattice spring model,DLSM)和4D-LSM模拟效果,展示了4D-LSM在处理岩石动态大变形破坏方面的优势。采用4D-LSM实现不同爆破设计参数下围岩损伤区深度的数值分析,结合质点振动速度实现对不同爆破方案的安全性评价。基于数值仿真对爆破方案安全性的敏感性定量评价为实现隧道岩石爆破方案的智能优化提供了支持。

The application of 4 D-LSM in rock blasting was studied.The fundamental principles of 4 D-LSM in tunnel surrounding rock blasting were introduced,including system equations,non-reflective boundary conditions and rock fracturing model based on multi-body failure criterion.Aiming at the blasting of tunnel surrounding rock,4 D-LSM was used to establish the surrounding rock vibration analysis model,single hole blasting model and surrounding rock damage model under blasting.On the basis of different tunnel blasting design schemes,these models were processed through geometric simplification and boundary condition simplification to realize the quantitative analysis of the peak load velocity of the key points of the tunnel blasting surrounding rock for the given blasting scheme.Aiming at the problem of singlehole free-surface blasting,the simulation effects of DLSM and 4 D-LSM were compared,and the advantages of 4 DLSM in dealing with large dynamic deformation and failure of rocks were demonstrated.The numerical modelling of surrounding rock damage zone depth under different blasting design parameters was realized by 4 D-LSM.The safety classification and ranking of different blasting schemes were realized through the prediction and analysis of particle vibration velocity and damage zone depth predicted by 4 D-LSM.The optimization of the tunnel rock blasting design could be realized by quantitative sensitivity analysis and ranking of blasting safety based on numerical simulation by using 4 D-LSM.