Research On Simulation Analysis Of Temperature Stress And Temperature Control Measures Of Rockfill Concrete Gravity Dams

Rockfill concrete is a new dam-building material that has appeared in the past ten years.Because of its use of large aggregates,good durability,low hydration heat temperature rise,and high construction speed,it has been used in hydraulic,railways and other fields.As of the end of 2020,104 rockfill concrete gravity dams have been built or are under construction nationwide.However,the current research results on temperature control measures of rockfill concrete dams are still very few and the study of temperature stress and temperature control measures of rockfill concrete gravity dams has great practical significance.This paper used the finite element software ANSYS as a platform and used parametric language to compile a set of analysis programs for analyzing the temperature field and stress field of rockfill concrete dams.Taking the non-overflow dam section of Wulongchong Rockfill Concrete Gravity Dam as the research object,a finite element simulation model is established for analysis;the temperature field and stress field without temperature control measures and five temperature control measures are simulated.The calculated results of control measures are compared with those without temperature control measures.The main research conclusions are as follows:(1)The temperature field of a rockfill concrete dam is determined by the adiabatic temperature rise of the concrete,the pouring temperature,the outside air temperature and the heat dissipation coefficient of the concrete surface.The highest temperature of rockfill concrete during the construction period is located inside the dam,and the highest temperature is closely related to the pouring season.The maximum temperature of the pouring block in summer can exceed 37℃,In this case,corresponding temperature control measures should be adopted.(2)The dam reaches a stable temperature about 3 years after the completion of the construction;the temperature field is distributed in layers during the operation period and the temperature of the water in front of the dam has a greater impact on the surface of the dam;after the temperature field stabilizes,the highest temperature in January is inside the dam body and the highest temperature in July is on the surface of the dam body.(3)Temperature has a certain effect on the first principal stress of the dam.The silo surface poured in the high temperature period will have a certain tensile stress after the pouring is completed;the main factor of the third principal stress is gravity;the tensile stress of the dam heel and dam toe during operation The pressure stress is relatively large,so geometric mutations at the heel and site of the dam should be avoided during construction,and more stress monitors should be arranged.(4)The implementation of temperature control measures can make the maximum temperature of the dam body drop below the allowable maximum temperature;Temperature control measures using surface running water in summer have a better effect than controlling pouring temperature;It is recommended to use them at the same time in the actual construction process;when the construction period permits,construction should be avoided during high temperature periods;In winter,insulation measures should be taken.