The Experimental Study On Yan’an Improved Colluvial And Residual Soil And Subgrade Settlement Deformation

The loess that with the features of porosity, permeability, easy disintegration and poor water stability can cause many engineering problems such as ground fissures, uneven settlement. The paper makes a summing up of domestic and overseas current research situation, explains the change of physical and mechanical properties of improved soil and embankment settlement rule.Base on yan’an new district project, detailed investigate the engineering geological and collected a large number of soil samples. Using cement, lime as curing agent, this paper carry out a series of tests, include consolidation test, unconfined compressive strength test and so on, study the changes of improved soil engineering properties. The test result show that the curing agent slag increase, the engineering properties of improved soil more stable, strength increase, and can get the reasonable proportion. Different scanning electron micrograph show that with the curing agent slag increase, the bonding state between soil particles change significantly, soil particles become larger, the reunion sexual enhancement, debris content increase, lime to soil particles "sand" is obvious. Particles and pore characteristics parameters that get from the SEM pictures can be used to analysis the pore and particles fractal dimension changes, study the relationship between the microstructure and the engineering properties. Finally, using the FLAC3D and layered summation method respectively analysis the subsidence deformation that under the gravity stress. Compared the two methods of calculation results, the subgrade settlement deformation law are analyzed.