基于松动圈理论深埋黄土隧道围岩压力计算方法

为研究深埋黄土隧道的围岩压力计算方法,通过对深埋黄土隧道开挖后的围岩应力状态进行分析,明确了松动圈的定义,推导了松动圈的表达式,提出了基于松动圈理论的深埋黄土隧道围岩压力计算方法,并基于现场试验监测数据,与既有计算方法的计算结果进行了对比分析,验证了该方法的适用性,分析了含水率变化对老黄土的物理力学参数和围岩压力的影响...

A Method for Calculating Surrounding Rock Pressure of Deep Loess Tunnel Based on Loose Broken Rock Zone Theory

The determination of surrounding rock pressure has always been the focus in the structural design of tunnel engineering, and the engineering characteristics of loess tunnel cause the determination of its surrounding rock pressure to be significantly different from other rock tunnels, especially deep-buried loess tunnels. By analyzing the stress state of the surrounding rock after excavation in deep loess tunnels, the definition of loose broken rock zone is defined, and the calculation formula of the loose broken zone of the surrounding rock is deduced. A method for calculating the surrounding rock pressure of deep-buried loess tunnels based on the loose broken rock zone theory is put forward. Based on the field test data, the applicability of the method is verified by a comparative analysis with the existing calculation method.The results show that the loose broken rock zone is the inner part of the plastic zone, which is the part where the tangential stress in the plastic zone is less than the initial ground stress. The broken rock zone of loess tunnels is much larger than that of ordinary roadways and rock tunnels, indicating that the loess tunnel is more susceptible to tunnel excavation. The calculation results of the proposed method are closer to the measured value of loess tunnels than that of other calculation methods and it is able to provide better safe allowance to some degree. Thus, the calculation of the surrounding rock pressure of deep-buried loess tunnels with the broken rock zone theory is feasible. It is more suitable for the soft surrounding rock of deep buried loess tunnel with certain self stability.