Analysis Of Temperature Field And Stress Field During Construction Period Of Rock-filled Concrete Dam And Control Of Cracks

Rock-filled concrete is a new type of concrete construction technology developed on the basis of self-compacting concrete technology.Its construction process is to build self-compacting concrete after rock-filled and use self-compacting performance of self-compacting concrete to fill the gap between the rocks,thus forming a whole block.Rock-filled concrete with dense and sufficient performance.Rock-filled concrete dam belongs to the scope of mass concrete in terms of size.The cracking of conventional mass concrete is almost inevitable.Most of the cracks are caused by the high temperature of concrete.Therefore,the study of temperature field and stress field of rock-filled concrete structure can reduce the occurrence of cracks,which has extremely important academic value and application value.Through monitoring the temperature and strain of rock-filled concrete structure during the construction period,we can understand the structure state of the mass concrete during the construction period,and then reduce the cracking of concrete by adopting reasonable construction measures.But the current research experiments on Rock-filled concrete are basically laboratory tests and small pouring block tests,and the actual pouring process of rock-filled concrete has not been tested in the project.In actual engineering,the study of temperature change and stress change of rock-filled concrete under construction conditions is still in a blank state.In this paper,by measuring the continuous three block in a concrete dam,the temperature change and strain change of the rock-filled and self-compacting concrete during continuous pouring are measured,and the changes of the temperature field and the stress field of the rock-filled concrete dam are analyzed by the numerical simulation,and the concrete construction workers are combined with the concrete construction workers.The control measures for temperature cracks of rock-filled concrete are put forward.The main research results are as follows:(1)The law of temperature field development in the construction period of rock-filled concrete pouring block: from the surface of pouring,the highest temperature is located in the middle of the block.The temperature is lower than the center.From the height of the pouring,the highest temperature is located in the structure core,the bottom temperature of the pouring block is lower than the temperature of the surface of the block;After the pouring is completed,the temperature of the block point is reduced slowly,the cooling rate of the block floor layer > the cooling rate of the central layer > the cooling rate at the bottom of the block.(2)The law of development of stress field in the construction period of rock-filled concrete pouring block during the construction period: after the completion of the pouring,the concrete pressure stress of the central part of the pouring block increases slowly to the peak,and after the peak is reached,the compressive stress will slow down because of the effect of concrete shrinkage and so on,then it decreases slowly with the change of time and finally reaches the dynamic state.Balance,the development trend of concrete compressive stress at the edge of the pouring block is that the compressive stress reaches its peak value within a period of time and then slows down slowly.The stress in the Y direction(long side direction)will slowly develop to the tensile stress,but it is always in a safe state,and the compressive stress in the direction of X and Z decreases slowly,but it will always be under pressure.(3)The development law of rock temperature of rock-filled concrete: the development law of rock temperature is consistent with the temperature development of self-compacting concrete.The temperature of rock in the middle of the block is always lower than the temperature of self-compacting concrete.The temperature of the pile stone at the boundary position of the pouring block is a period of time(about 100h)after the completion of the pouring.The temperature of the rock is higher than the temperature of the self-compacting concrete.(4)Through this study,ANSYS software can be applied to the simulation of temperature field and temperature stress in the construction of similar rock-filled concrete.The approximate calculation of the distribution of the maximum temperature and the internal temperature stress of the concrete is obtained,and the temperature control method is selected to control the production of the temperature crack in combination with the field measurement and the construction technology of the rock-filled concrete.