Temperature Effect Research During Construction Period On Concrete Gravity Dam Of Garden Hydropower Station

In the hydraulic engineering,the concrete gravity dam is one of the most important hydraulic structures,which is widely used because of its simple structure,strong adaptability,convenient construction and so on.However,there are some defects in the concrete gravity dam,such as the large size of the pouring,the poor thermal conductivity of concrete,and so on,which lead to the formation of the internal heat accumulation,which is easy to form a larger temperature difference to make the dam temperature cracks.Especially in the construction of concrete gravity dam in the cold region,the influence of temperature load on dam safety is more obvious.Therefore,the reasonable temperature control measures in the construction period is an important content.This paper is located in the cold area of the garden in Diebu County Gansu Province Hydropower Station Dam non overflow section of numerical calculation of the temperature effect during the construction period.The simulation process with temperature field,the calculation theory of finite element method for stress field and cooling water pipes,collect the actual engineering geology,hydrological and meteorological data,the simplified selection and construction process through the similar projects to complete the basic parameters of the material,assuming four different temperature control measures of the construction scheme,and the establishment of a threedimensional finite element model the selected section using the finite element software Midas FEA.The temperature field and stress field of the dam under different temperature control measures are obtained by simulation.By comparison with the results of the temperature field and stress field show that in the absence of temperature control measures for casting,casting layer temperature is lost rapidly and easily form a large temperature difference between inside and outside surface,low temperature season after casting casting layer for heat preservation measures,the pouring temperature loss slows,inside and outside surface temperature decrease,low temperature season casting on the casting layer of internal water cooling temperature control measures can not only make casting layer of hydration heat dissipating time shorter,can very good reduce pouring temperature,but considering the temperature lower casting warehouse too easy to cause subsequent casting layer surface temperature is too low,is not conducive to subsequent casting,casting is put forward in the low temperature season,or layer of casting is cooled,and on its outer surface heat preservation board of casting solution,the temperature control measures,after pouring the lowest layer temperature difference and will not affect the subsequent casting.In low temperature construction of concrete gravity dam,the dam body internal concrete hydration heat temperature rise more common areas biggest,lower inside the dam and concrete hydration heat is lost rapidly and dam body temperature balance or quasi equilibrium time needed for short.Dam construction process,the maximum tensile stress is always appear in the downstream of the dam toe,relative to a,pouring scheme of temperature control measures are not taken to low temperature season casting surface heat preservation measures,the first principal stress slightly rise,rise by 0.27 MPa,the second principal stress also increased 0.15 MPa;The primary stress can be reduced by 0.51 MPa,and the second main stress can be reduced by 0.05 MPa.After two kinds of temperature control measures were adopted in the low temperature season,the primary stress could be reduced by 0.51 MPa and the second main stress could be reduced by 0.32 MPa.Four kinds of casting solution allows maximum tensile stress are beyond the concrete tensile strength,the reasonable temperature control measures after the tensile stress in the dam body the rest parts are less than concrete tensile strength.So,to the maximum tensile stress in the downstream of the dam toe is easy to occur the scope of reinforcement and so on ways to improve the tensile strength,to avoid the cracking of the temperature,and ensure the safety of the dam construction and normal operation.The construction of concrete gravity dam in this paper,the low temperature simulation analysis of temperature control measures,draws some conclusion on the effect of temperature,can provide reference for the construction of similar projects in the future.