Influence Of Consolidation Pressures And Bond Strength On Mechanical Performance Of Microbial-Induced Calcite Precipitation Sand Investigated By Discrete Element Method

The Microbial induced calcite precipitation(MICP)treatment is a new technique to improve the weak and soft clay soil.It has the advantages of environmentally friendly.Hence,over the years several studies have assessed the method of MICP treatment of soil.The MICP samples are usually prepared in a state of low stress and then tested under uniaxial or triaxial condition.However,the soil in-situ has different confined pressures before treatment by MICP.Few researches have been conducted to investigate the effect of consolidation pressure on the MICP sand with different bond strength.In this research,the discrete element method was mainly employed to simulate uniaxial and triaxial compression tests on MICP sand.The models were established by discrete element method and verified by the results from the uniaxial test.In the simulated uniaxial and triaxial tests,the MICP sand samples with different bond strengths were consolidated under various pressures.The peak strength,residual strength,peak strain,failure strain and secant modulus were chosen to index the characteristics of MICP sand.Moreover,the deformation modes of samples at the peak strain and failure strain were analyzed.It is found that the peak and residual strength increases almost linearly as the bond increases.The secant modulus of the MICP sand under uniaxial test decreases as the bond increases due to a significant increasing of peak strain.Moreover,The modulus of before peak are nearly the same despite of various bond strengths.The peak strength,residual strength,peak strain,failure strain and secant modulus all increases with the increasing of the consolidation pressure.Therefore,the effect of consolidation pressure can not be ignored in test of MICP samples.