大坝基岩帷幕宾汉姆浆液灌浆的三维数值模拟

由于灌浆工程的掩蔽性和地质条件的复杂性,如何准确地确定复杂地质条件下浆液的扩散规律是灌浆数值模拟分析的关键及难点。目前,在水利工程中灌浆数值模拟的相关研究未考虑宾汉姆浆液扩散过程中两相流特征和大坝基岩的复杂地质条件;且主要以单一裂隙或单个灌浆孔为研究对象,均未进一步涉及浆液锋面的模拟。针对上述问题,本文建立包含不同地层、不良地质体和帷幕孔的三维精细地质信息统一模型,在CFD商用软件STAR-CCM+中采用耦合VOF法的三维非稳态宾汉姆浆液气液两相流灌浆模型,实现了宾汉姆水泥浆液在大坝基岩中的多孔分序灌浆精细模拟,并分析了浆液的扩散规律和灌后帷幕搭接情况。运用该模型模拟某水电站的基岩帷幕灌浆过程,结果表明:在一定时间范围内,浆液扩散半径随灌注时间而增加,但其变化率呈递减趋势;各序孔灌注完成后,浆液锋面搭接良好;将灌浆量和灌浆时间的模拟值与现场实测值相比,平均误差分别为9.08%和6.32%,模拟值与现场实测值基本吻合,验证了该模型的可靠性。

Three-dimensional numerical simulation of curtain grouting in the dam bedrock based on binghamian grouts

Because of the grouting engineering of masking and the complexity of geological conditions, how to accurately determine the diffusion regularity of grout under complicated geological conditions is the key and difficult point of grouting numerical simulation analysis. Binghamian grouts two-phase flow characteristics in the process of grout diffusion and complex geological conditions of dam bedrock is not considered in the present numerical simulation research of grouting in the hydraulic engineering. These research objects mainly focus on a single fracture or a single grout hole, while the simulation of grout front has not involved. Aim at the above-mentioned problems,a three-dimensional refined geological information model,included different formations,unfavorable geological body, curtains, grouting holes, was firstly established in this paper. Then, coupled with the volume of fluid (VOF) method in the CFD commercial software STAR-CCM +, a three-dimensional grouting mathematical model of Binghamian grouts air-grout two-phase flow was developed to achieve the numerical simulation of the multiple holes and sequencing grouting in the dam bedrock,also analyzing the grout diffusion rule and curtain lap after grouting. Finally,a hydropower station of bedrock curtain grouting process was taken as a case. The results show that the grout diffusion radius increases with time in a certain time range,but its rate of change shows a decline trend. After grouting completion of each sequence hole,grout front laps well. Furthermore,comparing the simulation value with the actual measuring value of the grouting quantity and time, the average errors were 9.08% and 6.32% respectively,which verified the reliability of the method.