The Study On Micro-structure And Engineering Mechanical Model Of Dianchi Peat Soil In Kunming Basin

As a particularity soil, dianchi peat soil is characterized by large organic matter content, larger void ratio and water content, poor physical and mechanical properties. Prone to uneven settlement buildings built on peat soil, so there are important theoretical and practical value through statistical analysis of the physical and mechanical properties, the microscopic structure of the analysis and the constitutive model research about peat soil.In this article about Dianchi peat soil survey data collected from Kunming Rail Transit Line 1 and 2, and its statistical analysis. Dianchi peat combined SEM and component analysi s of experimental, on peat soil micro structure qualitative and quantitative analysis. By uniaxi al consolidation test and triaxial test to analyze the mechanical properties of peat, made in lin e with Dianchi peat soils improvements Duncan - Chang model combined with the above an alysis. The main findings are as follows:(1) Collection undisturbed soil samples physical and mechanical properties data of Dianchi peat of Kunming Rail Transit Line 1 and Line, statistical and analysis data, List ranges north of the Dianchi Lake Dianchi peat physical force indicators, It has some of the construction guidance. Secondly, study its physical mechanics relationship between the various indicators, The results show that the natural moisture associated with better void ratio, and severe and void ratio, The void ratio of Dianchi peat can be obtained by empirical formula; Organic matter content and physical and mechanical indexes have smaller relationship; Correlation between the shear strength index by direct shear and consolidation of fast shear test method is very small, discrete large.(2) Through EDS analysis and Microscopic scanning electron microscopy test, It showed Dianchi peat clay minerals are illite, chlorite, kaolinite containing part; Analysis of previous studies and multiple sets of SEM picture of the structural characteristics of peat is mainly divided into three categories: a honeycomb structure, mounted skeleton structure, flocculation-like structure; Using image processing software on the SEM image processing to obtain quantitative microscopic parameters.(3) Through consolidation and conventional triaxial compression test, indicating Dianchi peat has certain structural, The compression of undisturbed soil with remolded have some differences, and explan its the microscopic behavior. Dianchi peat soil stress-strain curve can be divided into three stages: the first stage there is no damage to soil structure, the deformation is mainly elastic deformation; the second phase of soil structural damage, the proportion accounted for more than its plastic deformation of elastic deformation; the three staget that soil structure is completely destroyed, the nature of the soil close remolded.(4) Introduction Duncan - Chang model of the basic theory and formula to solve the required parameters, While the introduction of the concept of damage ratio. Duncan - Chang model with three different initial elastic modulus, Such as the initial elastic modulus of soil full stage, the initial stage of the elastic modulus of structural damage, the structure is completely broken in the initial stages of the elastic modulus. The model for comparison, shows that the modified model is more better describe the actual stress-strain soil traits.