从细观力学角度着手研究岩土等离散介质的变形和受力特性是一种重要的方法，基于细观力学理论的PFC2D数值仿真试验技术，可以从细观角度揭示注浆过程中拉压应力场的分布、土颗粒的变形运动及其与浆液的耦合作用过程等注浆进程的发展动态，为软弱土、风化岩和破碎带等不良地质体的注浆加固分析研究提供了一种新的途径。基于流固耦合原理的PFC2D颗粒流数值模拟程序，运用其内置FISHTANK函数库和FISH语言，分别定义流体域的流动方程和压力方程，对注浆过程中浆液的扩散过程、形态及颗粒的位移情况进行了数值模拟计算。通过调节PFC命令流中的hist,n_bond,s_bond和measure等参数，实现了颗粒体位移变动的追踪，并揭示了不同深度土体浆液的扩散规律和地层孔隙率改变等细观机理。数值计算表明，注浆压力对地层结构的改变和破坏作用十分显著，黏结强度增加劈裂效果逐渐变差，孔隙率随注浆压力提高则显著增大。基于Mohr-Colomb准则的弹塑性理论对钻孔周围土体的应力场进行理论推导，指出环向受拉径向受压的力学机制是劈裂注浆作用方式出现的根本原因。浆液黏度增加有利于提高劈裂-压密注浆的注浆效果，摩擦因数增加则对注浆效果影响不大。实验室试验对比分析表明，PFC2D模拟注浆过程是可行的。

It is an important method to study the deformation and stress characteristics of discrete media such as geo- chemistry from the perspective of micromechanics. Based on the theory of micromechanics,PFC2D numerical simula- tion test technology is used. The development of the grouting process such as the distribution of tensile stress field,the deformation movement of soil particles and their coupling with slurry can be revealed from a microscopic point of view. It provides a new way for the study of grouting reinforcement of weak soils,weathered rocks and broken belts. In this paper,based on the principle of fluid-solid coupling,the numerical simulation program of PFC2D particle flow is used to define the flow equation and the pressure equation of the flow domain. The diffusion process,morphology and parti- cle displacement of the slurry during the grouting process were numerically simulated. By adjusting Hist,n_bond,s_ bond,and measure parameters in the PFC command flow,the particle displacement changes are tracked,and the diffu- sion laws and formation porosity changes in different depths are revealed. The numerical results show that the effect of grouting pressure on the formation structure is very significant,the cracking effect of the increase of adhesion strength is gradually reduced,and the porosity increases with the increase of grouting pressure. The ElastoPlastic theory based on Mohr-Colomb criterion is used to deduce the stress field of soil around the borehole. It is pointed out that the me- chanical mechanism of circular pull radial pressure is the fundamental reason for the occurrence of splitting grouting mode of action. The increase of viscosity of slurry is beneficial to improve the grouting effect of split-compacted grou- ting, and the increase of friction coefficient has little effect on grouting effect. The experimental results show that PFC2D simulation grouting process is feasible.