块裂隧道围岩等效岩体变形参数研究

Study on Equivalent Deformation Parameters of Blocky Rock Mass for Tunnel

采用Voronoi离散单元方法建立块裂岩体隧道的随机DEM数值模型,通过大量随机数值计算结果验证采用岩体等效变形参数预测隧道收敛变形的可行性。在规则裂隙岩体等效变形参数计算方法的基础上,针对数值模拟揭示的深埋隧道变形特征提出改进的修正计算公式及相应的特征参数。通过与既有解答以及大量随机数值计算结果的对比和统计分析验证修正解的合理性,修正解较为合理改善既有规则裂隙岩体等效变形参数计算方法在反映随机块裂岩体在隧道卸荷条件下变形估算的较大误差。采用修正计算方法得到的岩体等效变形参数可以很好地预测随机块裂岩体中隧道开挖后收敛变形的数学期望值。提出的修正计算方法对当前深部岩体变形参数研究和隧道洞壁收敛位移的估算具有一定的参考价值。

A stochastic DEM numerical model of tunnel in blocky rock mass was established based on the Voronoi discretization method.The feasibility of using the equivalent deformation parameters of rock mass to predict the tunnel convergence deformation was verified by a large number of stochastic numerical calculation results.Based on the calculation method for equivalent deformation parameters of regular jointed rock mass,a modified calculation formula and corresponding characteristic parameters were proposed for the tunnel excavation in deep blocky rock mass.The reasonableness of the modified formula was verified by comparing with existing solutions and a large number of random numerical results.The modified formula was suitable to improve the calculation method of equivalent deformation parameters of regular jointed rock masses in reflecting the significant error in deformation estimation of randomly fractured blocky rock masses under tunnel unloading conditions.The equivalent deformation parameters of the rock mass obtained by the modified formula method can well predict the mean value of the tunnel convergence deformation after tunnel excavation in the randomly fractured blocky rock masses.The proposed modified formula can provide reference value for the current study of rock mass deformation parameters and the estimation of tunnel wall convergence displacement.