坝基裂隙岩体三维灌浆数值模拟

摘要

坝基灌浆工程地质条件复杂且具有隐蔽性,如何建立能准确反映岩体内裂隙分布情况的三维随机裂隙网络模型,并进行浆液扩散特征的研究是灌浆数值模拟的关键和难点.现有研究大多通过岩体揭露面统计资料估计裂隙的几何参数,无法有效反映复杂裂隙真实特征,且灌浆模拟研究中多将裂隙简化为单一裂隙或规则裂隙网络.本文采用Monte Carlo法建立三维随机裂隙网络模型;提出三维裂隙宾汉姆流体灌浆数学模型,实现对随机裂隙内宾汉姆浆液扩散特征的研究;运用该模型对某水电站坝基裂隙岩体灌浆过程进行模拟,结果表明:浆液主要在与灌浆孔相交的裂隙内流动,灌浆压力在灌浆孔附近衰减速率最快且对浆液扩散的影响较为显著.同传统裂隙灌浆模拟相比,该方法能有效反映复杂裂隙的真实特征,获取更贴近实际工程的灌浆结果,为保障灌浆工程的安全建设和经济合理性提供了理论依据.%It is important to have a good understanding of the accuracy of 3D fracture network model and the spread process of the grouting.Current 3D geological model are not efficient and cost-effective in visualizing complex fracture distribution for grouting simulation.Researches on grouting simulation simplified the stochastic fracture as one planar fracture or regular fracture network.To solve the above problems,the Carlo Monte method is adopted and a 3D stochastic fracture network model is established.Considering Bingham fluid characteristic,a three-dimensional grouting model is proposed.The bedrock curtain grouting of a hydropower station is taken as a case.The results show that the grout almost flows in the fractures that pass through the borehole,and grouting pressure decreases the fastest near the borehole and affects the diffusion markedly.Compared with the traditional results,this method can not only reveal the actual fractures features,but also obtain more reliable simulation results,which provides a reliable theoretical basis for engineering safety and economic efficiency.