基于ANSYS的钢筋混凝土倒虹吸非线性有限元分析及优化设计

发布时间：2018-08-14 14:29

【摘要】：倒虹吸管作为应用广泛的交叉工程和重要的隐蔽工程,在国际上素有生命线工程之称,其结构的应力、变形与外形尺寸、填土厚度、填土性质、初始边界条件等因素之间存在着复杂的相互作用,而且除满足正常输水要求外,对结构进行合理的设计也十分必要。因此,为保证整个结构体系的稳定、安全和经济性,对倒虹吸结构和周围土体进行合理的分析和计算,进而对结构进行优化设计就显得尤为重要。本文基于数值模拟法,以黑龙江省依安农场河北灌区主干渠穿西太平川沟倒虹吸工程为研究对象,通过运用有限元分析软件ANSYS,首先对工程运行中遇到的5种工况,采用钢筋混凝土的整体式模式,建立原设计方案下的管身和周围土体的三维实体模型,分别分析管身和周围土体的应力和变形。其次结合分析得到的管身应力值,对倒虹吸的初始断面及配筋进行优化,并利用分离式的配筋形式,对优化后的倒虹吸管身进行两种较不利工况下的模拟分析,验证改进后设计方案的可靠性,对比优化前后的工程量和造价,分析其经济性。本文的主要研究内容和结论如下:(1)介绍有限元的基本原理及分析过程、ANSYS的求解步骤,分别总结概括混凝土、钢筋、土体三种材料的本构关系和破坏准则及钢筋混凝土有限元分析中钢筋的处理方式。(2)根据原设计方案中管身的有限元分析结果,可得出在工程运行的5种工况中,管身混凝土最大拉、压应力均远未超过其设计值且有较大的富余,管身较不利工况出现在管内无水的完建和检修工况。(3)根据原设计方案中管身周围土体的有限元分析结果,可得出在不同工况下,土体整体是稳定的,最大沉降量发生在完建期,位于管身两侧回填土的自由表面处,其值为16.2 mm。管身整体沉降均匀,最大下沉量约为10.3 mm,满足倒虹吸管对地基沉降量的设计要求。管身地基最大压应力值为114 k Pa,地基承载力较好,满足本工程地基承载力的设计要求。(4)结合ANSYS数值模拟得到的洞身应力值,对初始的倒虹吸结构进行优化设计,根据改进后结构的有限元分析结果,可以发现优化后的倒虹吸结构是安全的。通过对比优化前后的工程造价,发现改进后的设计方案可以使造价大幅降低。
[Abstract]:Inverted siphon, as a widely used cross-engineering and important concealed engineering, is known as lifeline engineering in the world. There are complex interactions among the stress, deformation and shape of the structure, fill thickness, fill properties, initial boundary conditions and other factors. Besides satisfying the normal water conveyance requirements, the structure is reasonable. Therefore, in order to ensure the stability, safety and economy of the whole structure system, it is very important to analyze and calculate the inverted siphon structure and surrounding soil reasonably, and then optimize the design of the structure. The inverted siphon ditch project is taken as the research object. Firstly, by using the finite element analysis software ANSYS, the three-dimensional solid model of the pipe body and the surrounding soil body under the original design scheme is established for the five working conditions encountered in the project operation. Then the stress and deformation of the pipe body and the surrounding soil body are analyzed respectively. The obtained stress value of the pipe body is used to optimize the initial section and reinforcement of the inverted siphon, and the optimized inverted siphon pipe body is simulated and analyzed under two unfavorable working conditions by using the separated reinforcement form. The reliability of the improved design scheme is verified, and the cost and quantity of the project before and after optimization are compared to analyze its economy. The research contents and conclusions are as follows: (1) Introduce the basic principle and analysis process of finite element method, and the solving steps of ANSYS, summarize the constitutive relation and failure criteria of concrete, steel bar and soil, and the treatment method of steel bar in the finite element analysis of reinforced concrete. (2) According to the finite element analysis results of pipe body in the original design scheme, It can be concluded that the maximum tensile and compressive stresses of the concrete in the pipe body are far from the design values and have greater redundancy in the five working conditions of the project. The unfavorable working conditions of the pipe body appear in the complete and maintenance conditions without water in the pipe. (3) According to the finite element analysis results of the soil around the pipe body in the original design, the soil integrity under different working conditions can be obtained. The maximum settlement occurs at the free surface of the backfill on both sides of the pipe body, and its value is 16.2 mm. The overall settlement of the pipe body is uniform. The maximum settlement is about 10.3 mm, which meets the design requirements of the inverted siphon for the settlement of the foundation. The design requirement of foundation bearing capacity. (4) Combining with the stress value of the cave body obtained by ANSYS numerical simulation, the initial inverted siphon structure is optimized. According to the finite element analysis results of the improved structure, it can be found that the optimized inverted siphon structure is safe. By comparing the engineering cost before and after optimization, it is found that the improved design scheme is feasible. So that the cost will be greatly reduced.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV672.5

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