Study On High Liquid Limit Soil Foundation Treatment Technology Of Mountainous Freeway

China's southwest mountainous areas are widely distributed high liquid limit soil, with the rapid development of economic, more and more expressway had to be build on high liquid limit foundation, and high liquid limit foundation engineering problems have received increasing attention. Base on foundation treatment project of Chongqing Shizhong Expressway, this paper makes a systematic study on the high liquid limit soil foundation treatment technology, and achieved some positive results.According to the field exploration, reference material and laboratory test, this paper sums up the major features of high liquid limit soil: high water content, high compression, low permeability, high contractility, sensitive, uneven distribution and so on. Aimed at the complex geological and climatic conditions of mountainous areas, this paper presents using geogrid reinforced cushion and gravel pile composite foundation to improve high liquid soil foundation.By using elastic-plastic finite element analysis method, the mechanism and the influence factors of the geogrid reinforce cushion and the gravel pile are studied in this paper. The influence of interaction between geogrid (pile) and soil has been taken into consideration. Meanwhile, the centrifugal model test is used to estimate the effect of foundation treatment and provide revision for the theoretical analysis. Results show that the foundation treatment measures greatly reduced the deformation of high liquid foundation, and can also improve the foundation stability.This paper also makes a study on the construction technology, and presents construction control technology and quality standards.Base on the theoretical analysis, numerical simulation and model test, this paper makes a systematic study on the high liquid limit soil foundation treatment technology, draw some general conclusions. These conclusions provide a reliable theoretical basis for practical application and further research.This paper got supported by the project"Subgrade construction technology under complicated geological conditions of Shizhong Expressway".