水平布局对双洞穿越岩堆边坡隧道的稳定性影响

Stability Effect of Horizontal Layout on Twin Tunnels Crossing Rock Mass Slope

以麻柳湾—昭通高速公路老营盘隧道工程施工为背景,在详细分析工程地质条件及断面的基础上,运用理论分析和数值模拟等方法,确定了岩体本构模型与力学参数,建立了双洞隧道模型并设定了监测点,结合隧道采用上下台阶法开挖实际情况,对水平间距分别为20,25,30m 3种工况进行了分析。结果表明,3种工况安全系数分别为1.57,1.59,1.67,随着水平间距的增大,安全系数逐渐增大,但水平间距超过一定距离后对边坡稳定性影响不再增加,发现双洞水平间距为25m时最优。

Taking the construction of Laoyingpan Tunnel of Maliuwan to Zhaotong highway as the background and based on the detailed analysis of engineering geological conditions and section,the theoretical analysis and numerical simulation method are used,the constitutive model and mechanical parameters of rock mass are determined,and then a twin tunnels model is set up and monitoring points are set. Combined with tunnel excavation method,the stabilities of the horizontal spacing 20 m,25m and30 m are analyzed. The results show that the three conditions of safety coefficient are 1. 57,1. 59,1. 67,and with the increase of the horizontal distance,the safety factor increases gradually but the influence on slope stability is no longer increased when the horizontal interval is beyond a certain distance. The horizontal interval with 25 meters of twin tunnels is optimal.