Deformation Features Under Seepage And Deformation Constitutive Model On Peat Soil In Kunming Basin

The peaty soil in Kunming basin is a special soil,its engineering mechanics properties is special because of it has high natural water content and low coefficient permeability and has Weak expansion. In order to understand the deformation characteristics of the peaty soil in Dianchi lake area.the paper choose the peaty soil at Dianchi lake area in Kunming basin first, and then according to field engineering test data, combination the data in model simulation test, to study the deformation characteristics of peaty soils at the soil under load and seepage. On the basis of the model test, to use mathematical analysis building the deformation constitutive model of peaty soil in seepage and under the load,to provides the theory basis for civil engineering construction.This paper use the model test to help study, the model scale about 1:6, and the model container is a rectangular parallelepiped box have specification is LxBxH=1.4mxlmx1.2m. Take the disturbed peaty soil sample in northern Dianchi lake the model box, at the same times, place the a certain amount of soil pressure gauge and pore wate pressure gauge and displacement meter and other instruments to measurement the Related parameters of peaty soil.Let the disturbed peaty soil sample and instruments inside it cross the natural spray settlement consolidation until 6 months leter, to make the soil volume close to undisturbed sample volume, then, its density and void ratio and other physical and mechanical properties of the disturbed peaty soil sample reached the level of undisturbed peaty soil.By loading and seepage test and monitoring, we collected a large number of test data. Through analyzing the test data, we can reached the following conclusions:(1) Use the vibrating string type soil pressure box and pore water pressure and multi-point displacement meter and other instruments to measure soil stress and displacement and other parameters is feasible. In which the multipoint displacement meter to measurement soil vertical displacement and deduction the derivation of its deformation is quite useful; soil pressure gauge and pore wate pressure gauge also has a high measuring accuracy and stability, it for the similar geotechnical tests provide a reference.(2) Kunming peaty soil is a special soil, it is an elastic-plastic object, has a certain expansion, which belongs to the weak expansive soil. In the absence of osmotic conditions, its has different deformation to general soft soil, the lateral deformation is greater than vertical deformation; In the process of Limited compressed, the porosity of the soil changed overall smaller, reflect the soft soil vertical mechanical strength is good, vertical joints is overall development, ballast effect on permeability the overall smaller. In the osmotic conditions, its has More complex deformation, pore water pressure rate of change show up from top to bottom, change of deformation rate is similar with the pore water pressure variation.(3) Based on Real-time monitoring the soil deformation and pore water pressure and soil pressure, according to the theory of The generalized Hooke's law and The Deformation theory and The principle of effective stress, the paper we discusses and establishes a stress and strain constitutive model. the model with the field test data combined and calculation, results fit well, it explain the model is basic fit for simulation of osmotic conditions of the Kunming basin peaty soil deformation law.This experimental study due to loading conditions was limited, not for under the higher loading intensity condition of seepage deformation conduct in-depth test, but the test results for what's next high intensity loading conditions of the seepage deformation test laid preliminary foundation. Initial deformation law for the further research and provides a new experimental design basis.