基于压力拱理论的深埋节理岩体隧道围岩压力研究

Study on surrounding rock pressure of deep jointed rock tunnel based on pressure arch theory

为研究节理岩体隧道围岩压力计算方法,以隧道压力拱理论为基础,通过离散元数值模拟分析了岩体的坚硬程度、完整程度和结构面的抗剪强度对隧道压力拱的影响,应用多元线性回归拟合了多因素围岩压力公式,并结合依托工程对拟合公式进行了适用性分析。结果表明:节理岩体隧道压力拱范围为拱顶到最大主应力方向的偏转点,隧道压力拱高度随着节理间距和结构面的抗剪强度的增大而减小,岩体力学参数对压力拱高度的影响较小;与现场实测的围岩压力相比,计算误差在15%以内。所提围岩压力公式适用性良好,为节理岩体的围岩压力计算提供了新的思路。

To study the calculation method of rock pressure in jointed rock tunnels,based on the theory of tunnel pressure arch,the influence of rock hardness,integrity,and shear strength of structural planes on tunnel pressure arch was analyzed through discrete element numerical simulation.Multiple linear regression was applied to fit the multi factor rock pressure formula,and the applicability of the fitting formula was analyzed in combination with engineering support.The results indicate that the range of pressure arch in jointed rock tunnels is the deflection point from the arch crown to the direction of maximum principal stress;The height of tunnel pressure arch decreases with the increase of joint spacing and shear strength of structural planes,and the influence of rock mechanics parameters on the height of pressure arch is relatively small;Compared with the measured rock pressure on site,the calculation error is within 15%.The proposed formula for surrounding rock pressure has good applicability and provides a new approach for calculating the surrounding rock pressure of jointed rock.