劈裂注浆加固土体的数值模拟和试验研究

Numerical simulation and experimental study on soil split grouting reinforcement mechanism

针对目前有关土体劈裂注浆加固机理方面的研究,并未区分注浆挤密作用、浆脉骨架作用对于土体强度影响的问题,通过三轴压缩数值分析与室内试验研究注浆挤密作用和浆脉骨架作用对被注土体黏聚力、内摩擦角及在不同围压条件下的压缩强度及变形的影响规律,获得土体劈裂注浆加固效果的主控因素。研究结果表明:浆脉嵌入土体内部,破坏了土体的完整性及非均质性,且土体与浆脉的力学性质差异性较大,当两者发生较大相对位移时,将导致显著的非协调变形;浆脉边缘存在应力集中,首先出现破坏并逐渐向土周边发展,最终相互搭接形成宏观破坏面;注浆挤密作用是提高土体强度的主控因素,限制液扩散范围,提高注浆压力,强化注浆挤密作用是保证注浆加固效果的关键。

Considering that current research of soil split grouting reinforcement mechanism does not clearly distinguish between grouting compaction effect and slurry vein skeleton effect on soil strength, the effects of grouting compaction and slurry vein skeleton on cohesion, internal friction angle, compressive strength and deformation properties of soil under different confining pressures were studied by numerical analysis and laboratory tests. Hereby, main controlling factor affecting split grouting reinforcement and calculation method of grouting quantity was obtained. The results show that the embedded slurry vein destroys the soil integrity and heterogeneity. Since the mechanical properties between soil and slurry vein are significantly different, a large non-coordinated deformation occurs when the relative displacement is large. Due to the stress concentration, the plastic deformations first appear on slurry vein edges, then extends to the soil gradually, and the macro shear surface is formed when plastic deformations overlap each other. Grouting compaction effect is the main controlling factor, and controlling the grouting slurry distance, reaching the grouting engineering quantity, strengthening the grouting compaction effect are key factors to ensure the effect of grouting reinforcement.