Control Of Casting Length Of Concrete Blocks And Discussion On Its Reason

With the rapid development of domestic economy,in order to meet the needs of water supply reservoir,construction of large pool also entered a peak period.At the same time,the problem of cracks in the pool concrete structure is also attracting more and more attention.Pool wall concrete structure is one of the most common and the most widely used form of construction in our country.The main function of fresh water pool is to regulate the peak water storage in the water supply system,but due to the weakness of the material itself(lower tensile strength)and the external environment,the emergence of cracks is inevitable of.Cracks mentioned here refers to the macro cracks visible in the project,the width of 0.25 mm or more.According to the causes of cracks,which can be divided into two categories,one is due to the load generated by the structure of the cracks,the cracks in the structure is under the action of the load,in some parts of the tensile stress exceeds the tensile strength of concrete materials Strength caused,also known as "load cracks";The other is due to shrinkage deformation of concrete materials,temperature changes and concrete corrosion caused by corrosion and other causes of cracks,also known as "non-load cracks".Although the cracks often appear in the project,which do not affect the safety of the structure temporarily,it will impair the normal function of the building such as heat preservation and waterproofing,and cause the user’s psychological discomfort.Moreover,from the long-term requirement of the structure,Will affect the durability and service life of the house,which will also affect the safety of the structure.At present,the calculation of crack width at home and abroad is mainly based on the calculation of the crack width based on the theoretical formula under the action of load,and there is seldom quantitative research and discussion on the reason of the "non-load" factors on the crack of the concrete structure of the pool structure.Therefore,in this paper,the causes of the "load cracks" and "non-load cracks" and the corresponding treatment methods are analyzed in this paper.Secondly,according to the engineering practice,through the standard manual calculation and the century Qiyun reservoir software simulation and calculation Finally,based on the optimal section length of the pool wall,Abaqus,a large-scale finite element analysis software,was used to simulate and analyze the causes of cracks in this project.The conclusions are as follows:(1)According to the conventional algorithm,calculate the maximum distance between pool expansion joints as 24.7518 m;(2)The finite element design software was used to model and calculate the width of concrete cracks under the conditions of temperature(wet)difference is 24.2m.Finally,through comparison,it is known that the length of the expansion joint of the tank pool wall of the project is calculated on the premise of satisfying the design specification,that is,the optimal length of the one-time pouring concrete is 24.2m;(3)Abaqus software was used to simulate and analyze the “ load action ” and“temperature(difference)action” that caused the deformation of the pool,and finally concluded that under the same conditions,the temperature(difference)effect on the overall deformation of the pool.The impact of the larger;(4)In view of the influence of temperature(difference)on the water pool,a series of measures such as shortening concrete transport time,accelerating the speed of concrete warehousing,shortening the exposure time of concrete,and applying thermal insulation and shade to concrete transportation tools were proposed.