基于有限体积法的动水砂层注浆扩散特性研究

Study on the Diffusion Characteristics of Grouting in Dynamic Water Sand Stratum Based on Finite Volume Method

基于多孔介质-流体体积(VOF)法,利用ANSYS-Fluent计算流体力学(CFD)软件,研究动水砂层注浆扩散特性。建立圆管渗流数值计算模型验证了ANSYS-Fluent多孔介质模型渗流问题数值计算方法的有效性。依据柱形扩散公式,推导出适用于多孔管注浆模型的粘性阻力系数修正公式。基于前人模型试验,建立一维注浆和二维注浆模型,研究浆液在动水砂层中的运移和扩散机制。结果表明:采用ANSYS-Fluent多孔介质模型得到的砂土渗流速度模拟值与采用达西定律得到的渗流速度理论值的最大误差为2%;浆液顺水扩散范围大于逆水扩散范围;粘性阻力系数经修正后,二维注浆模型浆液扩散范围数值模拟值与试验值最大误差为0.29%;动水砂土浆液扩散受挤压效应和冲刷效应共同作用;研究结果对于完善动水砂层注浆理论具有重要意义。

Based on the porous media-Volume of Fluid(VOF)method,ANSYS-Fluent computational fluid dynamics(CFD)software is used to study the diffusion characteristics of grouting in the dynamic water sand stratum.The numerical calculation model of circular pipe seepage was established to verify the effectiveness of the ANSYS-Fluent porous media model in the seepage problem.Based on the cylindrical diffusion formula,a modified equation for the coefficient of viscous resistance applicable to the porous pipe grouting model is derived.Based on previous model tests,one-dimensional grouting and two-dimensional grouting models are established to study the transport and diffusion mechanisms of slurry in dynamic water sand stratum.The results show that:The maximum error between the simulated values of seepage velocity of sandy soil obtained by using the ANSYS-Fluent porous media model and the theoretical values of seepage velocity obtained by using Darcy’s law is 2%.The slurry diffusion range downstream is greater than the diffusion range upstream.After the coefficient of viscous resistance is corrected,the maximum error between the numerical simulation value and the experimental value of the slurry diffusion range of the two-dimensional grouting model is 0.29%.The slurry diffusion in the dynamic water sand stratum is subject to the combined effect of the squeezing effect and washout effect.The results of this study are of great significance for improving the theory of grouting in dynamic water sand stratum.