隧道断层带注浆加固围岩体爆破动力损伤特征  

Damage characteristics of grouted tunnel rock mass in fault zones induced by blasting

作　　者：吕国鹏 周传波[1] LYU Guopeng;ZHOU Chuanbo(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China)

机构地区：[1]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《岩石力学与工程学报》2021年第10期2038-2047,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金面上项目(41972286)。

摘　　要：隧道穿越断层破碎带时为了避免突水、塌方等灾害发生,可以采用预注浆加固再爆破开挖的施工方案。明确注浆加固围岩的爆破动力损伤特性对隧道穿越断层破碎带安全施工具有重大意义。以赣深高铁龙南隧道穿越F8断层施工为例,采用双孔声波法测试得到隧道爆破后注浆加固围岩的声波波速随深度分布规律。基于应力判据和弹塑性本构模型,建立了岩体统计损伤模型,通过Fortran编译生成新的LS-DYNA求解器,采用完全重启动算法计算了10个循环爆破开挖作用下隧道注浆加固围岩的累积损伤演化和分布规律,与现场声波测试得到的围岩损伤分布基本吻合。数值分析结果表明,爆破后隧道注浆加固围岩的最大损伤深度位于仰拱底部,在需要锚杆锚固的拱顶、拱肩和拱腰等部位平均损伤深度均未超过2.5m;隧道上台阶和中台阶部位开挖面围岩上损伤程度最大,但损伤深度较浅,除拱脚外其他关键部位开挖面上围岩损伤程度较小但损伤深度较深。When a tunnel crosses a fault fracture zone,in order to avoid the occurrence of water inrush,collapse and other disasters,the construction plan of pre-grouting and then blasting excavation is often used. It is of great significance to clarify the blasting damage characteristics of grouting rock mass for the safe construction of the tunnels through faulted fracture zones. This paper takes the construction of Longnan tunnel of Ganzhou-Shenzhen high speed railway through fault 8 as an example. The distribution law of acoustic wave velocity with depth in the surrounding rock after tunnel blasting was obtained using the two-hole acoustic method test. Based on the stress criterion and the elastoplastic constitutive model,a statistical damage model of the rock mass was established,and a new LS-DYNA solver was generated by Fortran compilation. The cumulative damage evolution and distribution law of grouting reinforced surrounding rock of the tunnel under the effect of 10 cycles of blasting excavation was calculated by using the complete restart algorithm,which basically matched with the field acoustic testing results. Numerical analysis results show that the maximum damage depth of the surrounding rock is located at the bottom of the inverted arch after blasting,and the average damage depth does not exceed 2.5 m at the vault,the shoulder and the waist of the arch,which need anchor anchoring. The degree of damage to the surrounding rock in the arch foot of the upper and middle steps of the tunnel is the most serious,but the depth of damage to the surrounding rock is small. However,the degree of damage to the surrounding rock in other key areas besides the arch foot is small but the depth of damage is large.

关 键 词：隧道工程 隧道爆破 注浆加固围岩 爆破损伤 统计损伤模型 

分 类 号：U45[建筑科学—桥梁与隧道工程]