The Research On Deformation Characteristics And Filler Amelioration Treatment Technology Of Reconstruction And Expansion Of Highwaysubgrade In Lake Region

Dongting Lake region is one of the marketable grain bases in our country.The development of road traffic in this region has an important significance. With the development of economy, a lot of roads have been unable to meet the needs of local traffic.The roads are badly in need of expansion.Combined with the widening project of Nanxian-Maocaojie road, characteristics of subgrade’s deformation of road expansion project in lake region and improved treatment technology of filler in lake region are researched by methods of numerical simulation and indoor tests in this paper. The main work can be given as follows.(1)This paper selected the representative sections and studied the difference between properties of foundation soil under new and old subgrade by geological survey and laboratory soil tests. Investigation and experiment showed that, the physical and mechanical properties of foundation soil under new and old subgrade have a certain difference, especially the compression and strength index.(2)Characteristics of subgrade’s deformation in expansion project was studied through numerical analysis of finite element.It was studied that how modulus of elasticity,density, cohesion,internal friction angle of the new subgrade’s filler influence the deformationof new and old subgrade. Improving elastic modulus of new roadbed filler can effectively reduce the vertical deformation of new subgrade.The maximum vertical displacement of new subgrade increases with the increasing new roadbed filling density in a direct proportion.(3)Through the study on compaction test and CBR test of the lake region’s filling soil and lime modified soil,this paper found the law of effects of the different initial water content on the CBR of the filler,providing the humidity control standards for the construction of subgrade filling.This paper studied the compaction characteristics and the CBR characteristics of different doses of lime modified soil,providing a basis for the determination of the construction control parameters (water content, compactness, lime content). (4)Combined with actual project,new and old subgrade’s deformation was observed and validated with theoretical analysis. The observed results and the results of finite element analysis is consistent.