内填植物纤维生土基砌块生态复合墙体斜截面极限承载力可靠度分析

发布时间：2018-09-12 05:09

【摘要】：针对提高传统生土房屋抗震能力的要求，实现传统生土房屋的生态节能，课题组将生态复合墙结构与传统生土房屋有机结合，相互取长补短、各汲优点，提出一种内填植物纤维生土基砌块生态复合墙结构。该结构体系既继承了生态复合墙结构良好的抗震性能，又具有生土材料因地制宜、节能环保的优良特点，实现了结构安全性、适宜性与良好经济性的统一。本文采取试验研究、理论分析和数值模拟相结合的方法，诠释内填植物纤维生土基砌块生态复合墙体受力机理，建立基于可靠度理论的墙体斜截面极限承载力的计算公式，为工程应用提供理论依据。本文着重研究以下问题：（1）介绍植物纤维生土基砌块的主要制备工艺及流程。通过力学性能试验，研究填充块材的受力特点，得到材料的基本物理、力学性能参数。用线性回归分析法拟合出材料的单轴受压本构方程，用两段直线构造出其单轴受拉应力-应变本构关系；对4榀1/2比例内填植物纤维生土基砌块生态复合墙体开展低周反复荷载试验研究，分析框格形式、高宽比对墙体的承载力、滞回特性、位移延性等抗震性能；试验结果表明：框格约束植物纤维生土基砌块，外框约束预制墙板，各组件分阶段释放能量，实现了墙体的功能分区，使墙体具有多道抗震防线；墙体XML-1、ECW-2发生合理的“强柱弱板”剪切型破坏，墙体ECW-3发生不利的“强板弱柱”弯曲型破坏，高宽比较大的ECW-4发生不利弯剪型破坏模式，工程中应注重墙板框格划分及高宽比控制；4榀墙体从屈服阶段到破坏阶段，墙体的延性较好、等效粘滞阻尼系数均有明显增大，均未出现倒塌，有效改善传统生土墙的抗震性能。（2）采用ANSYS建立的墙体数值模型，并对其进行静力弹塑性分析，计算结果与试验结果在荷载-位移曲线、钢筋应变等方面吻合较好；在此基础上，开展关键参数变化的墙体数值扩展分析，获得框柱配筋率、轴压比等关键因素对墙体弹性刚度、承载力的影响规律；基于试验研究及数值结果，分析墙体的抗剪机理，依据极限平衡理论，建立了内填植物纤维生土基砌块生态复合墙体斜截面极限承载力计算公式，并利用试验数据和数值结果验证式的适用性。（3）基于随机响应面基本理论，引入均匀设计表，提出基于改进的随机响应面法的内填植物纤维生土基砌块生态复合墙斜截面极限状态方程可靠指标计算公式；利用该方法建立了内填植物纤维生土基砌块生态复合基于可靠指标理论的斜截面极限承载力计算公式，，为实现工程应用提供了理论依据与安全储备。
[Abstract]:In order to improve the seismic capacity of the traditional raw soil houses and realize the ecological energy saving of the traditional raw soil houses, the research group organically combines the ecological composite wall structure with the traditional raw soil houses, and makes up for each other's weaknesses and takes advantage of each other. A kind of ecological composite wall structure of plant fiber raw soil block is put forward. The structure system not only inherits the good seismic performance of the ecological composite wall structure, but also has the excellent characteristics of raw soil materials according to local conditions, energy saving and environmental protection. It realizes the unity of structural safety, suitability and good economy. In this paper, by means of experimental study, theoretical analysis and numerical simulation, the stress mechanism of ecological composite wall with plant fiber raw soil block is explained, and the calculation formula of ultimate bearing capacity of inclined cross section of wall based on reliability theory is established. It provides theoretical basis for engineering application. This paper focuses on the following problems: (1) the main preparation process and process of vegetable fiber raw soil block are introduced. The mechanical properties of filling blocks were studied by mechanical properties test, and the basic physical and mechanical properties of the materials were obtained. The uniaxial compression constitutive equation of the material was fitted by linear regression analysis, and the uniaxial stress-strain constitutive relation was constructed by two straight lines. The low cycle repeated load test was carried out on 4 ecological composite walls with 1 / 2 ratio of plant fiber raw soil block. The seismic performance such as carrying capacity, hysteretic characteristics and displacement ductility of the wall were analyzed in terms of frame form, aspect ratio, and hysteretic property. The test results show that: the botanical fiber raw earth block is restrained by frame lattice, the precast wall panel is restrained by outer frame, and the energy is released by stages of each component, the functional partition of wall is realized, and the wall has multi-seismic defense line; The wall XML-1,ECW-2 has reasonable shear failure of "strong column and weak plate", the wall ECW-3 has unfavorable "strong plate and weak column" bending failure, and the ECW-4 with large height and width has unfavorable bending and shear failure mode. In the engineering, we should pay attention to the partition of the panel, frame and lattice and the aspect ratio control. From the yield stage to the failure stage, the ductility of the wall is better, the equivalent viscous damping coefficient is obviously increased, and none of the walls collapses. (2) the numerical model of the wall established by ANSYS is adopted, and the static elastoplastic analysis is carried out. The calculated results are in good agreement with the test results in the aspects of load-displacement curve and steel bar strain. On this basis, the numerical expansion analysis of the wall with the change of key parameters is carried out, and the influence of the key factors, such as the ratio of frame column reinforcement and axial compression ratio, on the elastic stiffness and bearing capacity of the wall is obtained, which is based on the experimental research and numerical results. On the basis of the ultimate equilibrium theory, the ultimate bearing capacity of the ecological composite wall with plant fiber and raw soil block is calculated, and the shear mechanism of the wall is analyzed, and the ultimate bearing capacity of the ecological composite wall is calculated. Using the experimental data and numerical results to verify the applicability of the formula. (3) based on the basic theory of random response surface, the uniform design table is introduced. Based on the improved random response surface method, a formula for calculating the reliability index of the limit state equation of the slope cross section of the ecological composite wall of the plant fiber raw soil block is presented. By using this method, a formula for calculating the ultimate bearing capacity of oblique sections based on the reliability index theory is established for the ecological composite of plant fiber raw soil blocks with inner filling, which provides a theoretical basis and a safe reserve for engineering application.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU311.2

【相似文献】