大相岭泥巴山隧道岩爆防治数值模拟分析

Numerical Simulation Analysis of Rockburst Prevention in the Nibashan Tunnel

大相岭泥巴山隧道为雅安—泸沽高速公路的控制性工程,由于隧道埋深大、地应力高、穿越的地层主要为硬脆性围岩,洞室开挖后岩爆时有发生。文章以该工程为背景,通过数值模拟分析了开挖中采用锚喷支护措施对减弱或防治岩爆的效果,并对不同锚杆长度和间距的防治效果进行了对比分析。结果表明:采用锚喷支护能够降低最大主应力、增大最小主应力、减少主应力差,可以有效降低岩爆的烈度;采用间距1m、长度3m的锚杆进行锚喷支护最经济有效。

The Nibashan tunnel is the key project on the Ya＇an - Lugu highway, and rockbursts occur frequently after excavation due to the depth, high geostress, and brittleness of the surrounding rock. Thus it is necessary to effectively prevent and treat rockburst in order to ensure the safety of personnel and equipment. Using this project as a background, this paper analyzes the effects of such preventive measures as sprayed concrete and rockbolts and compares different bolt lengths and spacings using a numerical model. The results indicate that the application of sprayed concrete and rock bolts can reduce the maximum principal stress, increase the minimum principal stress, reduce the difference of principal stress, and effectively reduce the intensity of rockbnrsts. It is very cost effective to use the 3m rock bolt with a spacing of 1m.