速凝浆液裂隙动水注浆扩散数值模拟与试验验证

Numerical simulation of crack grouting process of quick setting slurry with running water and its experimental verification

针对动水注浆中常用的2种速凝浆液,水泥–水玻璃浆液与高聚物改性水泥浆液,考虑浆液黏度时变特性,应用有限元计算软件COMSOL Multiphysics建立动水条件下裂隙注浆扩散的数值模型,研究动水条件下裂隙注浆扩散规律并分析不同黏度时变特性、初始动水流速与注浆速率对注浆扩散过程的影响,并将数值模拟结果与模型试验进行对比,验证数值模拟方法的有效性。研究结果表明:浆液扩散形态在逆水方向和顺水方向表现出明显的差异性;进水边界处的压力逐渐趋近于远端的地下水压强,注浆初期在裂隙边界附近及绕流区内流速较高,注浆后期整个裂隙内的流速变化幅度不大;在试验条件下,初始动水流速与注浆速率的提高均会导致裂隙内压力及流速的增加,注浆速率对裂隙内压力分布的影响比初始动水流速显著;C-S浆液与GT–1浆液扩散规律类似,但由于两者黏度时变性的差异导致两者扩散规律稍有差别。

C-S slurry and GT - 1 slurry are two types of quick setting slurry which are frequently-used in dynamic grouting engineering. Considering time-dependent behaviour of viscosity, and using COMSOL Multiphysics as the finite element software, numerical model of crack grouting process in running water was established. The law of slurry diffusion and its influencing factors were studied. Comparing numerical simulation and test results, rationality of numerical simulation is verified. Results show that. Running water restricts the range of slurry diffusion, and significant differences exist between along the flow direction and against the flow direction. Pressure around inflow boundary is gradually approaching the distal groundwater pressure. In initial stages of grouting, velocity in regions near the no flow boundary and outflow boundary is higher than other regions. In later stages of grouting, velocity in different position changes gently. Under the present experimental conditions, initial hydrodynamic flow rate and grouting rate are positive correlated with vdocity and pressure in crack. Furthermore, grouting rate shows more effect on pressure in crack than initial hydrodynamic flow rate. Slurry diffusion law of C-S slurry and GT - 1 slurry are similar, however, difference of time-dependent behavior of viscosity leads to quantitative differences of diffusion.