Causes and Prevention of Cracks in Concrete Slab of Rockfill Dam During Construction

In order to solve the common problem of cracking in the concrete slab of the rockfill dams during the construction period.A corresponding temperature-humidity coupling calculation program considering the dry shrinkage was compiled and verified,which based on the previous main research on temperature stress.The temperature stress,drying shrinkage stress and temperature-humidity coupling stress of the concrete slab of the rockfill dam were simulated,from the aspects of the concrete slab length,the restraint strength of the transverse joints on both sides of the concrete slab,the environment relative humidity and the measures of heat and moisture preservation,and the temperature,humidity and stress were comprehensively compared and analyzed.The numerical results showed that when the ambient relative humidity was 0.3,the maximum value of temperature-humidity coupling stress was nearly 2.46 times that of temperature stress.When the ambient relative humidity was 0.6 and the relative humidity decreases by the same range of 5%,the increase of tensile stress of formwork removal on the 60th day was nearly 2.28 times of that on the 5th day.In addition,the transverse joint restraint would lead to the maximum increase of the maximum tensile stress of the the concrete slab by about 75%.This paper explains the causes of cracks in the concrete slab of the rockfill dam during the construction period,obtains the "semi-quantitative" relationship,and finally puts forward related prevention methods,which can provide references for similar projects during the construction period.