基于离散裂隙网络的围岩注浆加固规律研究

Numerical Study on Grouting Reinforcement Effect on Fractured Rock Masses of Tunnels Based on Discrete Fracture Networks

基于输水隧洞裂隙围岩特征建立了二维离散裂隙网络模型,将宾汉姆流体在单一饱和裂隙中的两相流本构扩展到裂隙网络,模拟浆液在裂隙岩体中的流动扩散过程,得到不同注浆时间下注浆圈的形成范围;将注浆圈导入三维裂隙网络模型,基于水力耦合计算研究了在衬砌和注浆加固下,隧洞围岩的应力、变形与水压分布特性。结果表明:围岩注浆圈几何形态受裂隙分布特征的影响,呈各向异性分布;衬砌可有效控制围岩变形,相比无衬砌的工况隧道最大位移量减少了约50%,而注浆圈的形成可有效降低作用在衬砌上的围岩应力,缓解由外水压力引起的应力集中。本文成果可为富水岩体中隧道和地下洞室等深地工程的加固设计提供技术支撑。

A two-dimensional discrete fracture network model was established based on the characteristics of the fractured rock mass of a water conveyance tunnel.The constitutive law for two-phase flow of Bingham fluids in a single saturated fracture was extended to fracture networks to simulate the diffusion process of grouts in fractured rock masses.The obtained grouting zones with different grouting times were input into a three-dimensional discrete fracture network model taking into account the coupled hydro-mechanical effect,and the distribution characteristics of stress,deformation and hydraulic pressure in the rock mass were numerically calculated.The results show that the geometry of the grouting zone is anisotropic due to the distribution characteristics of the primary fracture set.The lining can effectively control the deformation of the rock mass,and the maximum displacement is reduced by around 50% compared with the case without lining.The formation of grouting zone can effectively reduce the compressive stress acting on the lining and relieve the stress concentration caused by the external water pressure.These results can provide technical support for the reinforcement design of underground engineering such as tunnels and caverns in water-rich rock masses.