基于“浆–土”界面应力耦合效应的劈裂注浆理论研究

Split grouting theory based on slurry-soil coupling effects

浆液与土体的界面应力耦合效应对土体劈裂注浆过程具有重要影响,劈裂通道宽度由注浆孔向浆液扩散锋面处衰减。基于此,将劈裂注浆扩散过程简化为平面辐射圆,推导了劈裂通道内牛顿流体浆液的扩散运动方程,引入了半无限空间体均匀受力模型并获得劈裂通道宽度控制方程,最终得到劈裂通道宽度及浆液压力的空间分布方程。分析了劈裂通道宽度与注浆压力的空间衰减规律及浆液黏度、土体弹性模量对注浆扩散过程的影响。研究结果表明:注浆压力与劈裂通道宽度的空间衰减趋势具有一致性且均呈现出明显的非线性特征,在注浆孔附近及靠近浆液扩散锋面区域衰减较快;浆液扩散半径与浆液黏度、土体弹性模量负相关。最后通过工程实例对浆脉厚度理论计算值进行了验证,浆脉厚度计算值比现场揭露浆脉厚度实测值大30%左右,计算误差处于可接受范围内,验证了理论的合理性。

The slurry-soil coupling effects have a great influence on the process of split grouting. The thickness of grouting vein has an attenuation from the region near grouting hole to the diffusion front. The process of split grouting is simplified into horizontal radiation circle. An equation for slurry motion in split channel is derived using the Newtonian fluid constitutive model. By introducing the force model of semi-infinite space, the governing equation for the thickness of grouting vein is derived. Finally, the spatial distribution equation for the grouting pressure and thickness of grouting vein is obtained. The spatial distribution response of the thickness of grouting vein and the grouting pressure is analyzed. The influence of slurry viscosity and elastic modulus of soil on process of split grouting is analyzed. The results show that the pressure attenuation trend in the radial direction is nonlinear, and that the change rate near the grouting hole and diffusion front is higher than that in other regions. The attenuation trend of thickness of grouting vein is similar to that of pressure. When the slurry viscosity and elastic modulus of soil are smaller, the grouting diffusion radius is larger. By comparing the theoretical model with the engineering example, the theoretical thickness of grouting vein is 1.3 times larger than that of the measured one.