Study On The Effect Of Soil Component And Microstructure On Mechanical Strength Of Peat Soil In Dianchi Lake

The peat soil is also known as the turfy soil.It is formed by inadequate decomposition of plants under anaerobic conditions. Kunming is located in the Tien Lake watershed, Tien Lake in the south, and the other three sides are mountains.Tien Lake has many river branches, forming a relatively closed waters.And combined with the sunshine and moderate temperatures,there are plentiful wet plants. So the peat soil were distributed widely in the Tien Lake basin. In recent years,Kunming construction is developing in the surrounding area,so constructing high-rise buildings, roads on the peat soil foundation is hard to avoid.But the peat soil is special soil,with large void ratio, high water content, high compressibility,and high organic matter content, it’s engineering mechanics properties is poor.Buildings on the foundation are easy to be damaged due to uneven settlement.Therefore, the study of this paper has great theoretical significance and practical value.The basic physical and mechanical experiment was conducted on the soil,such as grain analysis,specific gravity test,consolidation test and shear test.Based on the mechanics test,microstructure detection means and component analysis test.We analyzed the microstructure, material composition and mechanical properties of Tien Lake peat soil.And we concluded the influence of microstructure on the strength mechanism.Through the analysis of test data,we can draw the following conclusions:(1) The Tien Lake peat soil is a special soil whose physical and mechanical properties are very poor, with small natural density, high natural moisture content, large porosity, low permeability, high compressibility and low shear strength.(2) The basic unit of the soil is the flocculation and coagulation block, overhead between the basic units, and it forms loose skeleton, shows frame structure.(3) Using matlab to turn the image into binary image, then calculate the binary image, it is concluded that the void ratio is2.2469.It can be seen that the pore is large, interlinked, and well developed.(4) The main structure of the soil is overhead structure composed of clay minerals with plant residues. Unit grain group is flocculation structure. So the soil have large pore ratio, high moisture content and high adsorption capacity, and it also determines that the engineering geological characteristic of peat soil is poor.