Similar Experimental Research On Bearing Deformation Characteristics Of The Loess-lime Soil Foundation

The loess-lime soil foundation is a widely used and effective manner to treat collapsible loess foundation, which uses lime soil replace some or all of the soil under the foundation to eliminate collapsible and improve the bearing capacity. That the nature of the lime soil and loess exists obvious differences determines the loess-lime soil foundation bearing performance not only depends on the strength of the upper part of lime soil cushion, but also influenced by stress and strain characteristics of the soil lager. Therefore, the double-layered foundation composed by loess-lime soil should be as a whole object to study. In summary of the results before, combining with the state grid project, a similar model experiment to study loess-lime soil foundation is conducted in this paper.After doing an extensive literature survey, the raw materials of soil similar material are selected, and analyzing the influences of each raw material on the nature of the mixed soil through laboratory conventional experiments. Selecting barite, loess, flying powder, diatomaceous earth to formulate lime-soil similar material; spar, flying powder, talc, diatomaceous earth to formulate loess similar material. After a large number of tests, the optimal combination ratio is determined. The artificial foundation is formed with lime soil and loess similar materials to conduct a static loading test. In addition, FLAC3D software is used to analyze the model experiment.The results show that the model test fit well with the numerical simulation analysis, which means that the simplified foundation model test can be used to simulate the loess-lime soil foundation, and the lime soil and loess similar materials used in the model test are appropriate. On the boundary of the loess-lime soil foundation, the vertical stress decreases with the increasing center distance and the thickness of cushion layer; the horizontal stress decreases with increasing thickness of cushion, first increases and then decreases with the increase of center distance. Under the load, the shear plastic zone of loess-lime soil foundation first appear on the soil lager in elastic deformation phase. After entered elastic-plastic deformation phase, shear deformation appears on edges of the foundation, and gradually to the interface. The breakdown mode of the loess-lime soil foundation is the comprehensive punching and shearing breakdown mode. The ultimate bearing capacity of the foundation increases with the increase of thickness of cushion layer, but the displacement decreases. When the thickness of cushion layer continues to be increased, the ultimate bearing capacity and the displacement variation decreases. When the thickness of cushion layer is over3meters, the failure surfaces are completely in lime soil cushion scope, the foundation bearing capacity has nothing to do with the soil lager. At this point, the breakdown mode of the loess-lime soil foundation is the comprehensive breakdown mode.