土体劈裂注浆过程的数值模拟及浆脉形态影响因素分析

针对现有数值方法对土体劈裂注浆中裂缝产生和扩展过程模拟困难的现状,采用自主研发的基于有限元与流体体积函数的数值方法对劈裂注浆过程进行了模拟研究,再现了土体劈裂注浆过程中裂缝的产生以及浆脉扩展过程。数值模拟获得的劈裂注浆浆脉扩展过程与已有理论分析及试验所得规律基本一致,表明采用该方法模拟土体劈裂注浆问题是可行的。在此基础上分析了注浆深度和土体模量两个因素对浆脉形态的影响规律。结果表明:数值模拟可以呈现劈裂注浆过程的几个阶段,包含"浆泡"挤密、初始竖向劈裂、斜向二次劈裂等阶段;在二次劈裂发生之前的挤密阶段和竖向浆脉扩展阶段,地层竖向位移增加较小,而二次劈裂之后的斜向浆脉的产生和扩展是地层竖向位移增加的主要阶段;随着注浆深度的增加浆脉的分支越来越少而且方向性更加明显,浆脉宽度也越来越小;随着土体模量的增大,注浆孔周边"浆泡"体积减小,浆脉的宽度逐渐变窄。工程实例的模拟表明,该数值模型能很好的反映工程现象,对工程实践具有一定的指导意义。

Numerical simulation of fracture grouting and influencing factors for morphology of grout veins

Considering the difficulty of simulating the initiation and development of cracks during the process of fracture grouting by the conventional numerical methods, a new numerical method is used to simulate and visualize the whole process which contains initiation of cracks, slurry intrusion and propagation of grout. The whole process of fracture grouting simulated by this method fits well with the existing theoretical analyses and test results, so that it is a feasible method to simulate the fracture grouting in soils. Based on this method, the morphology of the grout veins is analyzed under different grout depths and soil moduli. The research results show that with the increase of grouting depth, the grout veins have less branches and are more directional. With the increase of soil modulus, the volume of "grout bulk" around the grouting hole decreases, and the width of the grout vein becomes narrower. The simulation of engineering examples shows that the numerical model can well reflect the engineering phenomena, and it has some guiding significance to engineering practice.