Research On The Anti-cracking Technical Measures Of Railway Bridge Pier Mass Concrete In Plateau Arid Region And Summer

Due to the dry climate, large temperature difference between day and night in thenorthwest plateau region, the obvious features of season, and the relatively large factors ofmass concrete temperature field and stress field under the influence of environment, and theless piers of special study of mass concrete, as a result of which the existing constructionmethod and experience cannot be fully applicable to the northwest plateau environment. Withthe comprehensive construction of high-speed railway in northwest China, a large number ofmass concrete piers and foundation appear in the construction of railway Bridges. However,the mass concrete structure in the process of construction and service to cracks.So, how totake effective measures to reduce the construction method and maintenance of the cracks ofthe hazard is an urgent need to solve the problem.In this paper, based on Xining super-large bridge pier mass concrete project of Xigesecond-line of Qinghai-Tibet railway, the finite element analysis software MIDAS/FEA iscarried on simulation analysis of the bridge pier and the temperature field and stress field ofthe pile caps. Starting from the Sensitive parameters of mass concrete temperature field andstress field, the anchorage technology countermeasures of Summer plateau railway bridge pieron the surface of mass concrete construction in arid regions is explored. The main researchcontent as this:（1）Summarizing and studying the theory knowledge of mass concrete temperature fieldand stress field, introduces the selection of concrete thermodynamics parameters, mainlyincluding coefficient of thermal conductivity, temperature conductivity, convectioncoefficient and the heat source function of concrete.（2）Using MIDAS/FEA to obtain the simulation analysis of temperature field and stressfield of summer28#pier to provide the temperature and stress time history curve of pierconcrete, and a analyze detailed of the temperature control indicators stipulated by Massconcrete construction technology procedures (GB50496-2009), including the peaktemperature of concrete, Inside and outside temperature difference, concrete temperaturedifference between the surface and the environment temperature, and the rate of temperaturedroping, etc.（3）Analyzing and finishing field experiment data, to summarize the mass concretetemperature rising curve in summer. And according to the measured data, estimate ontemperature field using the traditional empirical formula. Finally, estimate value withmeasured values, the fem results, verify the reliability and effectiveness of MIDAS/FEAsimulation analysis by means of comparing estimates and the finite element calculation resultswith the measured values. （4）Starting with the sensitive factors that influencing the temperature field and stressfield of the mass concrete and the characteristic that plateau arid regions and construct insummer, study the anti-cracking technical measures that appropriated for plateau is suitablefor the summer drought region of railway bridge pier crack of mass concrete the constructionof railway bridge pier mass concrete in plateau arid region and summer.