多层土压密注浆抬升时上抬力计算分析

Calculation and analysis of uplifting force in multi-layer soil compaction grouting

建筑物注浆的关键是经过注浆后对既有建筑物的抬升效果进行动态控制和工后恢复,以此减小建筑物的不均匀沉降。考虑三维破坏机制,采用非线性Mohr-Coulomb破坏准则构建一个轴对称的土体破坏机制,对压密注浆的抬升作用进行力学分析。基于极限分析上限定理,通过变分计算求出单个土层地表隆起时上抬力的表达式,再将表达式推广到各个土层,得到多层土注浆抬升时上抬力的求解方程和土体破坏面的上限解,结合前人的计算结果对比分析来验证本文理论的正确性。

A key link in grouting construction is to dynamically control the lifting effect of existing buildings and recover after grouting,in order to reduce the uneven settlement of buildings.Considering the three-dimensional failure mechanism,this paper constructed an axisymmetric soil failure mechanism using nonlinear Mohr-Coulomb failure criterion,and analyzed the uplifting effect of compaction grouting.Based on the upper bound theorem of limit analysis,the expression of the uplift force on the surface of a single soil layer was obtained by variational calculation,and then the expression was extended to each soil layer,finally the uplift force of multi-layer soil grouting was obtained.The upper bound solution of the equation and the failure surface of the soil was combined with the previous analysis results to verify the correctness of the theory.