富水破碎带隧道的涌水常常会引起一系列地质灾害, 其中高黏性浆液作为一种治水材料, 在富水破碎带的治水过程中发挥了积极的作用. 实验测量得到了常用水泥浆液和高黏性浆液黏性随时间变化的规律, 并分析黏度变化对注浆治水的影响. 引入孔隙率、渗透率动态模型,建立了适用于富水破碎带注浆治水的流固耦合数学模型, 分析了高黏性浆液注浆过程中压力梯度、应变率和孔隙率变化, 确定高黏性浆液流动半径. 结合浅层填充挤压、深层高压挤密的注浆思路设置了排水减压孔, 参考计算结果设计试验方案. 通过监测隧道涌水量和检测钻孔取芯, 验证了数学模型和试验方案的合理性. 试验结果表明, 隧道涌水量下降了97%, 达到了封堵涌水的目的; 现场芯样充填饱满密实, 抗压强度较原始地层提高了2~4 倍, 围岩整体防渗性能和稳定性得到大幅提升. 该结果不仅验证了数学模型的合理性, 还为类似地层治水处理提供了新的思路.
关键词：
孔隙率; 黏性; 耦合; 压力梯度; 注浆
Gushing water causes many geological disasters in tunnel. High viscosity grout plays a positive role in water controlling under complex geological conditions. In this paper, time-varying viscosity of common cement grout and high viscosity grout are measured and analyzed with experiments. The principle of effective stress for porous medium is applied to analysis the fluid-structure coupling in grouting. Considering coupling physical variables, dynamic models of porosity and permeability are contained. The diffusion radius of grout thus can be defined by porosity and pressure gradient. By filling the shallow rock and compacting deep rock, holes are designed in the grout experiment to reduce static water pressure. The distance between grout holes is arranged referring to the calculation results. Then, rationality of the mathematical model and grout scheme is verified by water monitoring and strength testing. According to the results, gushing water reduces by 97%, and strength of rock increases by 200% to 400%, indicating that gushing water is stopped and the tunnel foundation enhanced.
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