Studies On The Experiment Of Ground Treatment And The Deformation Of Subgrade In Collapsible Loess Region

It is well known that the foundation as the carrier of the construction, so its intensity and stability can affect the normal use of the building directly. However, the relevant theoretical study lags behind the engineering practice. So in this dissertation, the subgrade of certain highway in Longxi was taken as an example. Firstly, the in-situ test was adopted to obtain the bearing capacity of loess foundation for the construction in the loess area. Then, the dynamic consolidation method was obtained to treat the loess. The bearing capacity experiment was executed on the treated subgrade. At last the consolidation deformation of the composite loess foundation was analyzed so as to provide some technical supports for the design of the practice engineering in loess area. The main original work includes:1. The experiment results of bearing capacity of loess foundation were obtained and analyzed by using many methods in-situ tests such as cone penetration test, pressuremeter test, and dynamic sounding test. The optimum method was ascertained to get the bearing capacity of loess foundation. Further more, the rank of loess collapse was ascertained to provide the foundation of ground treatment.2. The mechanism of dynamic consolidation method was analyzed firstly, and was used to treat the loess foundation. Then, the cone penetration test, pressuremeter test and dynamic sounding test were adopted to obtain the bearing capacity of the treated loess foundation and their effects were analyzed.3. Firstly, the treatment mechanisms of lime pile and granular pile were analyzed and the computational method of bearing capacity of the composite loess foundation was presented. Then the theory of consolidation of Biot's and the FEM were utilized to analyze and compare the character of consolidation and deformation of loess foundation treated by the lime pile and granular pile respectively. Further more, the numerical results are compared with the data of measurement.The mechanism and the engineering parameters of the loess foundation which were obtained through the in-situ test in this dissertation can be used for reference in the future similar ground improvement engineering.