基于弹性应变能特征的岩爆危险性预测研究

Prediction of Rockburst Dangerousness Based on Elastic Strain Energy Characteristics

深部岩体开挖会引起围岩弹性应变能释放,是岩体破坏的诱因之一。依托草果山隧道,开展多次地应力测试,采用基于最小二乘法的线性回归方法,考虑构造应力进行地应力反演,采用数值模拟手段,研究了隧道开挖过程中弹性应变能的分布特征,建立弹性应变能与岩爆等级的对应关系,并对现场岩爆进行预测。研究结果表明:隧道开挖会引起掌子面及其前方3 m范围内围岩弹性应变能下降,掌子面前方4~10 m范围内围岩弹性应变能增大;引起拱顶、拱脚和拱底区域弹性应变能增大,影响范围为1~2倍洞径;岩爆预测结果与实际开挖中岩爆发生情况基本相符,研究成果对深埋隧道设计和施工具有借鉴意义。

Excavation of deep rock mass will cause the release elastic strain energy of surrounding rock,which is one of the inducements of rock mass failure.For the Caoguoshan tunnel,a number of in-situ stress tests were carried out,and the in-situ stress inversion was carried out considering the tectonic stress by linear regression method based on least squares method.The distribution characteristics of elastic strain energy in the process of tunnel excavation were studied by using numerical simulation method,and the corresponding relationship between elastic strain energy and rock burst grade was established to predict.According to the relationship,the on-site rockburst is predicted.The research results show that the tunnel excavation will cause the elastic strain energy of surrounding rock in the tunnel face and its front within 3 m to decrease,and the elastic strain energy of surrounding rock within 4~10 m in front of the tunnel face will increase.The tunnel excavation will also increase the elastic strain energy of arch crown,arch foot and arch bottom,and the influence range is 1~2 times of tunnel diameter;the predicted results of rockburst are basically consistent with the actual occurrence of rockburst during excavation.The research results have reference significance for the design and construction of deep-buried tunnels.