Research Of Temperature Crack In Mass Concrete Baseplate Restricted By Foundation Soil

With the appearance of high-rise buildings, large span structures, special structures and large equipment-based, mass concrete has been applied to more and more buildings, bridges, roads, water conservancy and other fields, and also of mass concrete baseplate is more common in the underground structures. On one hand, the stress in mass concrete baseplate is caused because of the temperature difference of center and surface. On the other hand, with the concrete hardening, the thermal stress will appear due to concrete's shrinkage restricted by foudation soil. Once the stress generated from both above exceeds the ultimate tensile strength of concrete at the same age, temperature crack of concrete is sure to appear. It is obvious for crack to destroy the completeness, anti-water and water-tolerant behavior of the structures, and cause safety crisis of structures.On the basis of consulting a large number of references, this paper simply expounded the temperature crack's classification, causes and control measures of the mass concrete baseplate; according to the basic principles of heat conduction equation and various boundary conditions, a mass concrete baseplate's temperature field is established; introducing the basic concepts of thermal stress, through theoretical analysis, this paper obtained thermal stress's basic formulas and crack rules of the mass concrete baseplate; to further explore the characteristics of mass concrete baseplate's thermal stress, using large finite element program ANSYS, this paper simulated its variation and investigated the influence of different foundation horizontal drag coefficient and baseplate's size to the baseplate thermal stress restricted by foundation soil, summed up the stress, strain, displacement's variation. In addition, based on the numerical calculation, this paper proposed to set the length of the sliding layer in mass concrete baseplate construction. Analysis showed that the thermal stress of the mass concrete baseplate restricted by foundation soil will add with the foundation horizontal drag coefficient and the baseplate's size increasing.All research work here can be referred by engineer and researcher in the field.