Reserach On Application Of Fluid-solidified Soil In Subgrade Engineering

For the compaction degree of median lane replacement in road broadening engineering and bridge abutment back backfilling is insufficient because the space is too narrow to backfill compaction,this paper use " fluid-solidified soil " this new materials to solve the engineering problem,fluid-solidified soil with properties of high liquidity and self-compacting,is a good way to solve the construction problems and can make use of the local useless soil and it has good economic and environmental benefits.In this paper,the mix ratio study first discusses how to control the flow performance of fluid-solidified soil,and also explores the influence of fly ash and ZL soil stabilizer on the properties of fluid-solidified soil.Then,a series of laboratory tests were carried out about the mechanical properties and durability of the fluid-solidified soil based on the test results of the mix ratio study.Finally,the numerical simulation of the fluid-solidified soil in the roadbed engineering was carried out based on ABAQUS.The main research results are as follows:(1)The water solid ratio can better control the fluidity of fluid-solidified soil,while the cement soil ratio has no significant effect on the fluidity.Fly ash can improve the fluidity,but the strength of fluid-solidified soil will decrease if the amount of fly ash substitutes cement too much.The ZL soil stabilizer can increase the strength of the fluid-solidified soil.However,the strengthening effect of the stabilizer on the strength of fluid-solidified soil is weakened with the increase of the content of the ZL soil stabilizer.The effect of flow performance of fluid-solidified soil is not significant with the content of the ZL soil stabilizer.(2)In the unconfined compressive strength tes,discussing the influence of the strength of fluid-solidified soil with the curing age,liquid-solid ratio,the cement soil ratio,the experimental results showed that the strength increases with the increase of the curing age but strength growth rate slowed,fluid-solidified soil strength increases with the increase of the cement soil ratio,decreases with the increase of liquid-solid ratio;The relationship between unconfined compressive strength and the above three test indexes was investigated in CBR test,cracking test and modulus of reslience test.The results show that the unconfined compressive strength of fluid-solidified soil has a good correlation with CBR value,cracking strength and modulus of resilience.In the direct shear test,the effects of the cement soil ratio on the cohesion C value and the internal friction angle φ were investigated.The test results show that the linear correlation between the cement soil ratio and the cohesion C value of the four types of soil is good,but the rule of the effect of the the cement soil ratio on the internal friction angle φ is not obvious;The strength changes of fluid-solidified soil under different wetting and drying cycles and freezing-thawing effects were investigated in the wetting-drying resistance test and freezing-thawing resistance test,The test results showed that with the increase of the cement soil ratio,the ability of the four types of soil to resist wetting and drying cycles and freezing-thawing cycles was improved by varying degrees.In the dry-shrinkage test,the water loss rate,dry-shrinkage strain and dry-shrinkage coefficient of fluid-solidified soil were investigated.The test results showed that the water loss rate and dry-shrinkage strain all decreased with the increase of age,while the dry-shrinkage coefficient did not change significantly.(3)Through the numerical simulation study of fluid-solidified soil used in subgrade engineering coMPared with the traditional way of backfill coMPaction degree is insufficient,the application of fluid-solidified the raised modulus of reslience of subgrade soil,reduce the maximum tensile of stress in subbase.But in consideration of the constriction of fluid-solidified soil,it will increase the maximum tensile stress in subbase.If the shrinkage is too large,the contact between the old and new subgrade soil is not close,and the maximum tensile stress of the subbase will be increased.