| Concrete faced rockfill dam has become the first choice for high dam.It plays an important role in the development process of domestic and foreign water conservancy and hydropower resources.Domestic and foreign experts and scholars have affirmed its good development prospect.In the past decades,it has significantly increased in both quantity and height.The main engineering problem of concrete faced rockfill dam is that the excessive stress and strain of the dam body and the excessive stress and strain will lead to the damage of the slab and joint watertight structure,which will lead to the excessive leakage,and even the problem of infiltration or erosion damage,which will affect the normal operation of the slab and the dam body.In addition,the application of the combination of reliability analysis and random finite element in the reliability of dam is the trend of the development of the reliability theory of dam.Therefore,by considering the spatial variability of material parameters,this paper introduces the stochastic finite element method(SFEM)into the stress and strain calculation of the concrete faced rockfill dam,and establishes the noninvasive stochastic finite element method(NSFEM)based on the secondary development of MSC.Marc.Combining the reliability and FEM method,a method for obtaining the reliability and failure probability of points in the dam based on random finite element stress and strain is realized,and the stochastic reliability method for dam slope reliability based on Geostudio is developed.The main research contents and results are as follows:(1)Development of NSFEM method for concrete faced rockfill dam based on MSC.Marc secondary developmentFirstly,based on MSC.Marc,the secondary development of E-B constitutive model of rockfill is developed,then static calculation is carried out to verify the correctness of the secondary development.Secondly,random field simulation of material parameters is carried out and "noninvasive" development is carried out.Finally,it is applied to an engineering example to analyze and compare the stress-strain law of the concrete faced rockfill dam considering the spatial variability of material parameters.(2)Study the influence law of material parameter variation coefficient on the settlement value of dam bodyBased on the settlement monitoring data of Gongboxia concrete faced rockfill dam,this paper studies the influence of the variation coefficient of the spatial variability of rockfill parameters on the settlement of the rockfill dam.(3)Point reliability calculation based on stress and strain by stochastic finite element methodIt is generally believed that when the stress level is greater than 1,the structure appears obvious failure.In this paper,the stress level greater than 1 is considered as“shear failure",and the stress level less than 1 is considered as"safety".The point reliability of the dam is calculated.(4)Develop the stochastic reliability method for dam slope reliability based on GeostudioThe stochastic field simulation method was combined with SLOPE module of Geostudio to calculate the safety factor K of dam slope,and K<1 was considered as“failure”,K>1 was considered as "safety".The Monte Carlo method based on Latin hypercube sampling was used to calculate the reliability and failure probability.(5)The relationship between variation coefficient of material parameters,safety coefficient and reliability index was studiedUnder the premise that other material parameter values and stochastic field eigenvalues of other regions remain unchanged,the influence law of material parameter variation coefficient on safety coefficient and reliability index is obtained.The related results obtained in this paper are of certain reference value to more accurately obtain the stress and strain value of rockfill dam,and the variation coefficient of rockfill material parameters can be determined through the safe dam response value by using the relationship curve of variation coefficient and dam response value obtained in this paper,so as to guide the selection of engineering materials,dam filling,operation and maintenance. |
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