XING Haipeng1,2, WU Guanghua1,2, WANG Ge1, CHEN Kunyang1, LI Xiaolong1, ZHANG Bei1
Abstract:
The existing compaction grouting simulation method only can analyze the stress distribution after grouting, but cannot obtain the parameter information reflecting the compaction effect of grouting, such as the void ratio and density of soil after compaction. Therefore, a modified Cam-clay ( MCC ) model was introduced to describe the mechanical property of soil, and based on the elastic-plastic finite element theory, a simulation method was established to simulate the compaction grouting process of constant density slurry in soil. A more comprehensive and intuitive description of the formation compaction effect was achieved. The compaction grouting simulation analysis was carried out on clay, silty clay and other low permeability soil. Compared with the analytical solutioin and experimental results, the overall average relative errors of the simulated values and analytical solutions of radial stress and void ratio with different grouting pressures were 4. 04% and 0. 29%, respectively, and the average relative errors between the calculated void ratio and elastic modulus and the field test results were 5. 70% and 2. 85%, respectively, which proved the applicability of the proposed model. On this basis, the distribution characteristics of soil density, void ratio and elastic modulus around the grouting column after grouting reinforcement were analyzed. The results showed that when the grouting pressure increased from 0. 4 MPa to 1. 0 MPa at the grouting depth of 1. 5 m, the soil density, elastic modulus and void ratio at 0. 05 m from the center of the grouting hole approximated linear changes, and the average change rates werre 0. 148 g / ( cm 3·MPa) , 0. 808 and -0. 127 MPa - 1 , respectively. When the grouting pressure was 0. 4 MPa, the increase rates of soil density and elastic modulus and the decrease rate of void ratio at 0. 05 m from the center of the grouting hole gradually decreased with the increase of grouting depth. Overall, the density and elastic modulus of the soil around the grouting column were greatly increased after grouting reinforcement, and the void ratio was significantly reduced. The soil parameters changed less with the distance from the grouting hole, and gradually returned to the initial state. On the same grouting pressure condition, with the increase of grouting depth, the compaction effect gradually weakened.