The Environment Temperature Stress Analysis And Crack Control Of Overlong Basement Wall

With the rapid economic development and continuous improvement of engineering technology, a large number of long concrete structure building emerge out.Due to the impact of seasonal temperature changes, cracks are very common, and underground construction has water requirements, once the wall cracks resulting in leakage,it would lead to great danger. Therefore, the problem of cracks control in the concrete structure, become the focus of attention today.This paper introduces the basic theory of long concrete structure temperature field and thermal stress. Secondly, with Shenyang ambient temperature background, this paper used ambient temperature stress analysis theory, with the ANSYS finite element software, used elastic finite element analysis model theory,and established long basement structure simplified model.While analysis the ambient temperature effect of long basement structure simplified model, temperature load applied mainly is the most unfavorable temperature difference between indoor and outdoor when temperatures plunged down, without regard to the impact of the contraction. Then analysis linear elastic finite element,work out the distribution of temperature stress of the wall. And further research and analysis the impact of the wall length,wall height, wall thickness, soil thickness, temperature difference and concrete changes in the scope and intensity distribution of the basement wall temperature stress.On the basis of the above work,the research results of this paper are:(1) to basement side wall, the wall has a larger temperature stress in the cross-section along the longitudinal direction of the wall, and gradually reduces to the two ends, and in the height direction temperature stress decreases upward, and the short wall temperature stress is small.The analysis was prone to temperature stress usually appears in the direction of the longer dimension. Stress concentrate at the center of the floor plate to spread around, usually as stress, less prone to cracks; (2) wall temperature stress increased with length, but in the end tends to a constant value. (3) temperature stress increases with the height of the wall, temperature stress decreases, so as to the wall height and maximum stress is inversely proportional; (4) while temperature stress decreases with increasing the thickness of the wall, the floor has the larger constraints to the thin walls, so the thinner,the wall has more sensitive to temperature stress. According to this law, you can take some insulation measures to the thin wall, thereby reducing the temperature tensile stress; (5) soil has the insulation effect on the basement wall, and can reduce the ambient temperature effects of stress on the structure; (6) while wall length is 30m, when change the temperature, the stress in the wall of the small temperature difference across the wall is not changed. When the temperature difference is greater,the maximum temperature of the wall is generally greater than the concrete tensile strength standard value. Therefore, it is important to control the temperature difference to the wall of the basement; (7) the higher strength of concrete structures,the more sensitive to the ambient temperature stress effects.Finally, starting from the analysis of the results, in terms of materials, design and construction of structural measures, this paper introduced a number of technical measures in control of long basement concrete structural cracks.