Construction Of Clay Creep Constitutive Model Of Water Relief Zone In Reservoir Operation Period And Its Secondary Development In FLAC3D

At present,in the study of the creep characteristics of rock and soil in the drawdown zone of the reservoir bank slope,most of Them only consider the influence of a single factor(such as the moisture content of rock and soil itself or the number of times of wet dry cycles)on the creep mechanical behavior of the rock and soil masses,while the joint action of the two factors is ignored.Few studies can accurately describe the accelerated creep stage in the creep process of rock and soil,this makes the displacement calculation results often have large errors,and it is unable to accurately reveal the influence of periodic changes of reservoir water level on the creep mechanical behavior of rock and soil in the drawdown zone of the reservoir bank slope during the operation of the reservoir.In order to solve the above problems,based on the creep test data of o Ther scholars,considering the influence of the initial moisture content and the number of wet dry cycles on the creep characteristics of clay,the time-dependent damage function is introduced to establish the creep constitutive model of the falling zone clay during the operation period of the reservoir;On the platform of FLAC3 D,the second development of the model is realized by VC++;the three-dimensional numerical network model of woshaxi landslide is established.Combined with the monitoring data of the landslide deformation for many years,the burgers constitutive model and the creep model established in this paper are respectively used to simulate the creep process of the landslide,and the correctness and applicability of the constitutive model in the numerical simulation of the clay creep in the falling zone are verified.the results are as follows:(1)According to the evolution relationship between the creep mechanical properties of clay and the number of wet dry cycles,the creep damage elements of water content,wet dry cycles and Their combined action are combined in series with the classical Burgers model elements to establish the creep constitutive model of clay in the drawdown zone during the reservoir operation period.the model is used to fit the creep test data under one-dimensional stress state,and the Fitting degrees are 99.9% and 99.7% respectively,which verifies the applicability of the model in describing the whole creep process curve of the falling zone clay.(2)the constitutive equation of the clay creep model of the fading zone is deduced in the difference format under three-dimensional stress conditions,and the secondary development in the FLAC3 D software is realized by using the VC++ secondary development interface and the built-in Fish language,through numerical experiments Verification of the constitutive model shows that the strain-time curve of the numerical test and the triaxial creep test are in good agreement,which verifies the correctness of the secondary development of the model.(3)Compared with the Burgers model,the settlement-time curve of the Woshaxi landslide calculated using the creep model established in this paper is closer to the landslide monitoring data for many years,and the results obtained are closer to the actual situation.