考虑中主应力时土体劈裂灌浆力学机制的大变形分析

在塑性力学和大变形理论的基础上分析土体在劈裂灌浆初始阶段的力学机制，将劈裂灌浆的初始阶段视为无限土体中的圆孔扩张问题，并将圆孔周围土体中的应力分布分为两个区域。在弹性区中土体服从小变形假设，在塑性区中服从大变形假设。假设初始劈裂灌浆压力是圆孔扩张到极限时极限扩孔压力；当土体在灌浆压力作用下，大小主应力正好换位时，则出现劈裂时的灌浆压力就为二次劈裂灌浆压力值，推导出塑性区半径、劈裂灌浆的竖向劈裂灌浆和水平向劈裂灌浆压力的理论解答，同时也获得了弹塑性区中的应力场分布规律。该理论的计算结果与工程实测结果比较接近，初步证实了该理论的可靠性。

Mechanism analysis of fracture grouting in soil with large strain considering intermediate principal Stress

On the bases of the plastic mechanical mechanism and the large strain, the early phase of fracture grouting is regarded as the question of cavity expansion in infinite soil. The stress distribution due to the cavity expansion in soil is considered as two zones. The deformation following little deformation in elastic zone and large-deformation in plastic zone is taken into consideration. The initial fracturing grouting pressure is the limited expansion pressure and the second fracture grouting take place when the large and small stress of soil is conversion. On the bases of the stress equilibrium equation and continuous boundary condition of stress and deformation, the stress distribution in the elastic-plastic zones, the terminal plastic zone radius and fracturing grouting pressure are obtained. According to the compassion, the result of the present theory is very near to that of the engineering practice.