裂隙岩体注浆块体离散元方法模拟分析

Block-based DEM Modeling on Grout Penetration in Fractured Rock Masses

涌水是海底隧道建设面临的主要难题之一,注浆可以有效降低涌水并加固围岩,保障施工安全。采用块体离散元方法模拟研究了浆液裂隙耦合模型、裂隙剪胀等因素对裂隙岩体浆液扩散的影响规律。结果表明:(1)考虑浆液裂隙耦合作用对浆液最大扩散距离有显著影响,结合Barton-Bandis(BB)裂隙本构模型更能够反映裂隙变形的真实特征;(2)DEM数值模型表明偏应力导致裂隙发生的剪胀作用会增大裂隙开度,改变浆液扩散形态。依托青岛胶州湾海底隧道的施工设计及实测数据,采用块体离散元方法得到的注浆渗透规律与工程现场监测结果基本是符合的,误差在工程应用的允许范围内。

Water inflow is one of the main problems during the construction of subsea tunnels. Grouting can effectively reduce water inflow and reinforce surrounding rocks to ensure construction safety. Block-based discrete element method(DEM) is used to study the effects of fracture constitutive model and deviatoric stresses on grout penetration in fractured rock masses. The results show that:(1) Barton-Bandis(BB) fracture constitutive model can more accurately reflect the real characteristics of fracture deformation induced by grouting;(2)dilatancy caused by the deviatoric stress leads to significant changes in the patterns of grout penetration. Finally,block-based DEM is used to model grout penetration in fractured rock masses. The modeling results of Qingdao Jiaozhou Bay Subsea Tunnel are in agreement with the monitoring data.