Research On Deformation Laws And Treatment Method Of Soft Soil Foundation In Zunchi Highway

With the rapid development of freeway construction, the designs and constructions of the roadbed projects with soft soil foundation conditions have been conducted in a wide range in China. The study on the deformation control of soft soil roadbed is an important subject during the construction of highway because of complexity of deformation mechanism and variety of influence factors. The deformation laws and treatment method of soft soil foundation in Zunchi highway are mainly studied. This abstract is introduced as follows.①The existing results are analyzed first, then the definition of the soft soil foundation, the distribution of the soft-soil in China and the significance of the soft soil foundation settlement are proposed.②Combined with soft soil foundation in Zunchi highway, geological characteris- tics and deformation features of the soft soil foundation are analyzed. The result of stability calculation and settlement calculation for the original fill couldn't meet the specifications, so fill subgrade are treated by dynamic compaction.③According to deformation features of soft soil foundation in Zunchi highway, effective reinforcement depth is determined, and the construction parameters about falling distance of rammer, tamping energy, tamping point arrangement and grid spacing are studied out. Besides, principle, features, technology, construction methods and construction control of dynamic compaction are introduced entirely, and dynamic compaction is applied to soft soil foundation in Zunchi highway.④Evaluation of treatment effects on soft soil foundation in Zunchi highway mainly contain the detection of foundation bearing capacity, settlement deformation of subgrade, lateral displacement of subgrade and pavement roughness. By in-situ test, including static load test, standard penetration test and cone penetration test, settlement deformation of subgrade and reinforcement depth achieves control index of the original design. From the result of settlement observation of subgrade, settlement velocity of previous period is great, but uneven and significant settlement don't happen for later observation in subgrade, and the settlement value is also controlled within 20mm. Finally pavement evenness is detected after construction, roughness index ofσand IRI could meet the specifications.