Research On Temperature Effect Of Concrete Box Continuous Aqueduct

In recent decades,with the rapid development of China's society and economy,the construction of water conservancy projects has also developed rapidly,and many modern aqueducts have been built.In the early stage,the aqueduct is small flow pattern,mianly used for agricultural irrigation.While the modern water diversion project and water diversion project are increasing,and the construction of aqueduct tends to be large flow and large span.In the construction of this kind of large aqueduct,there are many places to learn from the mature experience and technology of bridge engineering,because there are many similarities between aqueduct and bridge engineering.However,the aqueduct and bridge have different engineering functions,and they have differences in the design section,the force characteristics,and so on.Taking the actual engineering as an example,this paper discussed and studied on the temperature effect of the new concrete box continuous aqueduct,providing reference for engineering practice.The three-dimensional solid model of the zero number block of the aqueduct is set up according to the engineering example.Through this model,the hydration heat of the zero block concrete structure is analyzed and compared with the two working conditions of the ordinary concrete and the fly ash concrete.It can be found that the change of trend of its temperature field is that the surface temperature of aqueduct fluctuates with the change of atmospheric temperature,and it is also influenced by the internal hydration heat,and it rises and then decreases after pouring concrete.The internal temperature is mainly affected by hydration heat.It rises first and then decreases with time.However,due to the poor thermal conductivity of concrete,the temperature inside the box roof fluctuates slightly with time.The web and bottom plate of the aqueduct have a slower heat dissipation,and the internal temperature changes in a smooth curve.The temperature stress is mainly influenced by the range of temperature,and the trend of the stress value of the structural surface increases first and then decreases,and it is fluctuating.When the fly ash concrete is used,the temperature field and temperature stress field of the zero block can be obviously improved,the peak value of the internal temperature will decrease,the temperature difference between inside and outside will decrease,and the surface temperature stress will be reduced,which is conducive to the temperature control in the construction period of the aqueduct.This paper also analyzes the temperature effect of the continuous box aqueduct under the action of sunshine in summer by establishing a two-dimensional finite element model.By analyzing the temperature field and temperature stress field of the section under sunshine,it can be seen that the influence of sunshine on the temperature field of the aqueduct is obvious,especially the temperature change at the roof is the largest and the duration is long.When theaqueduct is carrying water,the range of temperature and temperature stress of the section are both large.By analyzing the range of temperature and fitting the quadric curve,it is found that the coincidence is very high.In the two cases,the lateral temperature stress of the inner surface of the roof is larger than the tensile strength of concrete,and it is easy to produce cracks.The longitudinal temperature stress on the lower section of the section is analyzed.And compared with the stress results of the reference railway code and the temperature difference model in the highway code,it is found that the stress value of the cross section under the cross section is large,and attention should be paid to the design of the aqueduct in this form.