Constitutive Model Of Structure Loess

Loess is a kind of typical structural soil,which is widely distributed in China.And a large number of engineering activities are carried out in loess area.On the other hand,due to the special nature of loess,the geological environment conditions such as hydrology and climate in loess area and the influence of human engineering activities,the disaster in loess area is extremely developed.So it is particularly important that how to correct understand the structural mechanics properties of loess,and how to find a constitutive model which can accurately describe the mechanical behavior of structural loess.Through this,we can accurately describe and predict the mechanical behavior of structural loess.In this paper,we use natural structural loess as the research object,through basic test to get the basic physical and mechanical parameters of structural loess,On the basis of the concept of superloading Cam-Clay model,in view of structural loess,We improved the evolution of structural state change parameters and a modified constitutive model is proposed.Fortran programming was adopted to verify the model by comparing with the one-dimensional consolidation test and the three-axis consolidated drainage shear test data.The work carried out mainly includes the following aspects:(1)The basic properties of L5 loess were determined by geotechnical experiments.The static side pressure experiment,one-dimensional consolidation experiment and three axial consolidation test were carried out for L5 original and remolding samples respectively.Comparative study on the structure of loess.(2)According to the structural loess,on the basis of the superloading Cam-Clay model,we analyzed the overconsolidation and structure of loess from the e-lnp curve.We improved the evolution of structural state change parameters by using the concept of void ratio.So we can make the model can better describe the natural loess in different before and after the yield stress strain relationship,make the concept of the parameters is more clear,a constitutive equation of structural loess is proposed.(3)The parameters of L5 model were determined by experiment and simple test.(4)Through basic test to get parameters of model,and comparing the data of one-dimensional consolidation experiment with the data of triaxial consolidated-drained shear experiment by Fortran program,we are sure that our model can effectively depict stress-strain relationship of structural loess.