Research On Inversion Of Earth-rockill Dam Material Parameters Based On Cloud Theory

With the development of China 's western region and the implementation of the strategy of power transmission from west to east,the number of earth-rockfill dams in China has increased year by year.At present,more than 95% of the built reservoirs in China are earth-rockfill dams,so earth-rockfill dams have developed into a common dam type.However,during the construction or operation of earth-rockfill dams,problems such as dam foundation deformation,dam body settlement,and instability will inevitably occur,and serious dam failures will occur.It is necessary to analyze the deformation of earth-rockfill dam,because it is the basis and important way for safety diagnosis and analysis of dams,and also an important way.For accurate deformation analysis of earth-rockfill dams,the authenticity of the constitutive model parameters must be guaranteed.However,there are many uncertain factors during the construction of the dam,so that the constitutive model parameters of the dam after construction are no longer the actual model parameters.Therefore,the uncertainty of the earth-rock dam system should be fully considered in the parameter calculation.In this paper,the parameters of the constitutive model are determined through triaxial shear tests to study the deformation of earth-rockfill dam materials.Because the test pieces used in the test are affected by uncertain factors,the physical properties of the dam material are affected.Because the test piece is affected by various uncertain factors during the test,the parameter results measured in the test have a certain deviation compared with the actual project.These will directly affect the accuracy of the dam deformation analysis results.Therefore,this paper introduces the cloud theory that has obvious advantages in dealing with uncertainty into the constitutive model parameter inversion research,so as to obtain the constitutive model parameters that reflect the characteristics of the soil as closely as possible and are consistent with actual engineering.The main results are as follows:(1)According to the basic principle of Duncan-Chang E-v model,the parameters of Duncan-Chang E-v model are calculated through the basic data of triaxial shear test,and the parameters to be inverted are determined according to the actual project.(2)Firstly,I assume that the parameters of Duncan-Chang E-v model are pan normal cloud distribution,and determine the cloud digital interval index according to the calculated parameters.Then the basic knowledge of cloud theory is learned and the finite element coupled positive analysis is carried out.The cloud digital interval index is used as the reference to construct the training samples of dam material axial deformation,lateral deformation and model parameters;In the next step,the multi condition and multi rule cloud generator is used to train the nonlinear mapping between the axial deformation,lateral deformation of the earth-rockfill dam material and the E-v model parameters of the consequent,so as to establish the uncertain cloud reasoning model for the parameter inversion of Duncan-Chang E-v model.(3)The parameters of Duncan-Chang E-v model calculated by triaxial shear test data are taken into the finite element analysis to calculate the axial deformation and lateral deformation of the specimen,and compared with the measured deformation.The conclusion shows that this algorithm can invert the parameters of Duncan-Chang E-v model well,and the inversion result has high precision.