考虑变压变浆的三维精细裂隙网络灌浆数值模拟

Variable pressure and variable water cement ratio-considered 3-D numerical simulation of fine fissure-network grouting

针对目前常见的裂隙岩体灌浆数值模拟研究多采用固定灌浆压力和水灰比与现有的变压变浆施工工艺不符,且现有研究中裂隙网络建模精度较低,导致数值模拟与实际灌浆结果存在较大差异的问题,提出了考虑变压变浆的三维精细裂隙网络灌浆数值模拟方法。通过引入相关一致性准则对拉丁超立方抽样进行改进,降低裂隙参数模拟过程的随机性,以提高裂隙网络的精度;进一步地,提出一种考虑变压变浆多孔分序灌浆模拟方法,通过实时统计模拟过程中灌浆孔内流量和累计注浆量的变化,根据规范对灌浆压力和浆液水灰比进行动态调节,实现灌浆过程精细化模拟。以杨房沟水电站帷幕灌浆工程为例进行案例分析,结果表明:与传统灌浆数值模拟相比,本文提出的模拟方法得到的浆液扩散半径更大,最终形成的灌浆帷幕范围更大更完整,且注灰量预测精度更高。相较于传统多孔分序灌浆模拟,该方法精度提高一倍以上,表明所提方法更具优越性。

Aiming at the problems that the most of the conventional studies on the numerical simulation of the fractured-rock mass grouting are made with fixed grouting pressure and fixed water-cement ratio at present,which are inconsistent with the existing construction technology of the variable pressure and variable water-cement ratio grouting,and the fissure-network modeling accuracies are lower in the relevant existing studies,which leads to larger differences between the results of the numerical simulation and the actual grouting,a method of variable pressure and variable water cement ratio-considered 3-D numerical simulation of fine fissure-network grouting is proposed herein.Through introducing relevant consistency criteria to improve Latin hypercube sampling,the randomness of the fissure parameter during simulation is lowered,so as to enhance the accuracy of fissure-network.Furthermore,a variable pressure and variable water cement ratio-considered simulation method for multi-hole sequential grouting is put forward by which the grouting pressure and water-cement ratio of the grout are dynamically adjusted in accordance with the relevant specifications through the real-time statistics of the changes of both the flow rate inside the grouting hole and the accumulated grouting amount,so as to realize the fine simulation of the grouting process.The curtain grouting project of Yangfanggou Hydropower Station is taken as the study case for the case analysis and the result shows that compared with the conventional grouting numerical simulation,the grout diffusion radius obtained from the simulation method proposed herein is larger and the finally formed curtain grouting range is larger and more complete with a higher prediction accuracy of the cement amount for grouting.Comparing with the conventional simulation of multi-hole sequential grouting,the accuracy of this method is more than doubled,which indicates that the proposed method has more advantages.