Experimental Study On Improvement Of Low Limit Silt As The Material Of Subgrade

Based on subgrade engineering of G218 Qing-Yi highway in XinJiang province, the author conducted a systematic study on how to improve and stabilize the silty soil of low liquid limit as the material of roadbed,by a large number of laboratory tests and theoretical analysis method ,combining with finite element analysis simulation software,study the mechanism and the results of the different improved methods.This study ,fistly,carried out a series of lab tests to obtain the basic parameters of its physical ,mechanical and chemical properties of the silty soil. Secondly, explore the use of cement for subgrade stabilization, under the different cement dosage, analyze the changes law of the unconfined compression strength, modulus of resilience and CBR value of the soil, and analyze the mechanism and influencing factors of the cement stabilized silt, determine the appropriate cement-dose which can be used in the actual project. Thirdly, we studied the physical method which can improve the stability of silt, that is to use the local natural gravel to improve the performance of the silty soil, and study the different proportion of sand and gravel mixing, study the changes of the compression modulus and the CBR value, and determine the appropriate blending ratio.Finally , we use the MARC finite element analysis software to simulate the program ,and to estimate the post-construction settlement and the roadbed stability under the different improvement program of silt ,and analyze of the effectiveness of filling subgrade with the different improvement programs.