Temperature Stress Research Of The Mass Concrete In Heterogeneity Of Rock

Mass concrete of civil and hydraulic engineering construction has a wide range of applications.However,the influence of the temperature rise of hydration heat leads to the large temperature difference of mass concrete.When the temperature of concrete is reduced,Cracks may occur in the concrete in the basic constraint parts,so the analysis and calculation of the basic restraint stress is an important basis for determining the temperature control measures of mass concrete.In the previous studies,it is assumed that the bedrock is homogeneous,and the bedrock is generally weak intercalated or cut by various structural planes,the actual bedrock is often uneven.Therefore,it is necessary to make a deep study on the influence of the uneven bedrock on the constraint stress of mass concrete.The finite element method for construction process and long duration temperature creep stress during operation are used to calculate the foundation restraint stress.In this paper,the APDL language of ANSYS is used to complete the calculation of the temperature field program,and considering the outside temperature,water temperature,surface water and other boundary conditions change process.It is difficult to solve the problem of long term creep calculation for common commercial software.By using UPFS(User Programmability)provided by ANSYS,the model of concrete creep exponential function is introduced,and the constitutive equation of elastic creep is established to realize the long time calculation of concrete creep stress.The influence of the heterogeneity of rock mass on the restraint stress of mass concrete is studied on the basis of the reliability of the program verified by a numerical example.In the study of the effect of inhomogeneous bedrock on the foundation restraint stress of mass concrete,it is considered that the weak bedrock is unevenly distributed,the weak bedrock is completely orthogonal to the normal bedrock,and this is an ideal model assumption.According to the study of this paper,the characteristics of the inhomogeneous bedrock on the basis of the temperature stress of mass concrete are mainly due to the following.Firstly,when the bedrock beneath the concrete is uneven,the first principal stress of the concrete at the base restraint site becomes larger and the bedrock cracks are more likely to occur,the greater the inhomogeneity,the greater the tensile stress of the concrete.Secondly,the maximum tensile stress position of concrete tends to change when it contains weak bedrock.Thirdly,in the concrete bedrock,even if the inhomogeneity is large,which has little effect on the tensile stress of the concrete at the foundation restraint,the temperature control can not be considered separately.Finally,the calculation of the elastic modulus of the bedrock is carried out,the results of the tensile stress of the concrete at the base restraint site are smaller and the results of the non-uniform stratigraphic modeling are actually considered,and this method is not suitable for the concrete temperature control calculation.The results of this paper have some guiding significance for the analysis of the foundation restraint stress of mass concrete.