周边孔外插角对隧道爆破超挖的影响:以巴岳山隧道工程为例

Influence of Surrounding Hole Angle on Tunnel Blasting Overbreak:Taking the Banyue Mountain Tunnel Project as an Example

为研究周边孔外插角对于隧道爆破开挖超挖的影响,依托铜安高速中的巴岳山隧道工程,采用ANSYS/LS-DYNA软件建立了隧道周边孔外插角为3°、4°、5°的三维数值模型,数值模拟计算得出结果后,分析围岩损伤以及有效应力与周边孔外插角大小的关系。结果表明:随着周边孔外插角的增大,超挖量也随之增大,外插角为4°和5°时岩体超挖超过了15 cm;当外插角大于4°和5°时,岩体的有效应力超过了岩体强度;基于对围岩损伤和有效应力的分析,周边孔的外插角不宜大于4°。

In order to study the influence of peripheral hole insertion angle on tunnel blasting excavation over-excavation,relying on the Tong an high-speed Banyue Mountain Tunnel Project,a three-dimensional numerical model with peripheral hole external insertion angles of 3°,4°,and 5°was established using ANSYS/LS-DYNA software.After numerical simulation calculation,the relationship between surrounding rock damage and effective stress and the size of peripheral hole external insertion angle was analyzed.The results show that with the increase of peripheral hole insertion angle,the amount of over-excavation also increases,and the over-excavation of the rock body exceeds 15 cm at the insertion angle of 4°and 5°.When the insertion angle is larger than 4°and 5°,the effective stress of the rock body exceeds the strength of the rock body.Based on the analysis of the damage to the surrounding rock and the effective stress,the insertion angle of the peripheral hole should not be larger than 4°.