黄土基坑中旋喷锚索支护结构工作性状研究

发布时间：2018-05-09 19:12

本文选题：旋喷锚索 + 基坑　；参考：《西安建筑科技大学》2017年硕士论文

【摘要】：锚固技术广泛应用于岩土边坡加固、建筑基坑支护、地下工程等中,旋喷锚索是近年来发展起来的一种较新的锚固技术工艺。相对于普通锚索,旋喷锚索承载力高、单位长度锚固力大、适用于更广的土层、施工过程中质量更容易保证,具有其相对优势。但对其研究相对较少,表现出理论研究落后于工程实践的现状。本文主要工作如下:(1)选取合适的剪切-滑移模型,对等截面与变截面旋喷锚索的荷载传递机理及力学性状影响因素进行分析;此外,推导并提出规范提供的锚索刚度公式的不合理性,建立并验证旋喷锚索刚度公式并对其影响因素进行分析。(2)通过锚索现场拉拔试验,得到旋喷锚索的极限粘结强度标准值、单位长度锚固力、界面抗剪刚度系数、锚索刚度及峰值抗剪强度等参数,分析了塑性位移发展规律,验证了锚索拉拔荷载-位移公式的合理性,并对普通锚索与旋喷锚索的刚度进行对比,说明旋喷锚索并未具有刚度方面的优势。(3)采用现行基坑支护规范方法,结合工程实际,对旋喷锚索与普通锚索分别用于在基坑支护体系中的作用和效果进行对比设计,说明旋喷锚索的优势,同时,对旋喷锚索分别采用规范刚度公式及本文建立的刚度公式进行支护体系对比设计,说明对支护效果的差异性影响。(4)采用有限元数值分析方法,研究锚索直径、水泥土模量、预应力及预应力分配对支护效果的影响。
[Abstract]:Anchorage technology is widely used in geotechnical slope reinforcement, foundation pit support, underground engineering, etc. In recent years, jet anchor cable is a relatively new Anchorage technology developed in recent years. Compared with the common anchor cable, the screw jet anchor cable has high bearing capacity and large anchoring force per unit length, which is suitable for the wider soil layer, and the quality in the construction process is easier to guarantee and has its relative advantages. But its research is relatively few, showing that the theoretical research lags behind the status quo of engineering practice. The main work of this paper is as follows: (1) selecting appropriate shear-slip model to analyze the load transfer mechanism and the influence factors of mechanical properties of the equal-section and variable-cross-section spout Anchorage cables. This paper deduces and puts forward the irrationality of the formula of anchor cable stiffness provided by the code, establishes and verifies the formula of anchor cable stiffness and analyzes its influencing factors. 2) through the field drawing test of anchor cable, the standard value of ultimate bond strength of screw jet anchor cable is obtained. The parameters such as unit length anchoring force, interface shear stiffness coefficient, anchor cable stiffness and peak shear strength are analyzed. The development law of plastic displacement is analyzed, and the rationality of the load-displacement formula of anchor cable drawing is verified. By comparing the stiffness of the common anchor cable and the rotary shotcrete anchor cable, it is shown that the rotary shotcreting anchor cable does not have the advantage of stiffness. (3) the existing foundation pit support standard method is adopted and combined with the engineering practice. The function and effect of rotating shotcreting anchor cable and common anchor cable in foundation pit supporting system are compared and designed, which shows the advantages of rotary shotcreting anchor cable, at the same time, The standard stiffness formula and the stiffness formula established in this paper are used for the comparative design of the supporting system, which shows that the difference influence on the support effect is analyzed by finite element numerical analysis method, and the diameter of anchor cable and the modulus of cement soil are studied. The influence of prestress and prestress distribution on support effect.
【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】：2017
【分类号】：TU753

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