地下工程预应力锚索支护设计参数研究

发布时间：2018-05-19 04:15

本文选题：地下工程 + 预应力锚索　；参考：《重庆交通大学》2014年硕士论文

【摘要】：岩土锚固可使地下工程围岩由荷载变为支护结构的一部分，最大限度地发挥围岩自身承载能力，以较小的支护力维持洞室的稳定。目前，，对于地下工程预应力锚索支护，还没有系统的设计理论和计算方法。论文以地下工程预应力锚索支护为背景，研究地下工程中预应力锚索的锚固支护原理、设计理论、计算方法、关键设计参数的确定方法等，为地下洞室预应力锚索设计提供科学的理论依据。论文主要研究内容如下： ①结合软弱围岩、大跨径洞室、高地应力围岩的变形机理以及锚索主动锚固支护设计的作用机理，论文主要从地下工程洞室围岩的稳定性以及围岩的变形控制两个角度出发，对洞室围岩进行了弹塑性分析。 ②基于软弱破碎围岩的弹塑性分析以及锚索的主动锚固原理,研究分析了洞室围岩的弹塑性变形、变形区域、群锚机理、主动锚固的作用机理，为洞室围岩的稳定性分析评价、锚索的布置方法、锚索长度确定、锚固间距确定等提供了理论依据。 ③提出了软岩围岩中锚索设计外荷载、锚索设计锚固力的确定方法。基于围岩的弹塑性分析，通过围岩稳定性判据可得出洞室所需支护力、通过工程类比经验法可确定洞室围岩的最大允许收敛值，进而反算求得满足洞室围岩变形要求所需支护力，根据同时满足围岩稳定性、围岩变形控制要求的支护力作为锚索支护设计的外荷载。最后根据锚索主动锚固条件下围岩的变形影响深度应大于围岩松动区厚度，确定锚索的锚固力大小是否设计合理；根据锚索锚固力是否满足现有规范要求等条件，确定锚索的主要设计参数。 ④提出了地下工程中锚长的确定方法。锚长包含锚固段长度、自由段长度，其中锚索的锚固段长度通过胶结材料与洞室围岩的胶结强度、胶结材料与锚索筋材间的胶结强度、锚固段形式、安全系数、锚固体直径以及围岩地层力学性质等因素来确定；锚索自由段长度通过围岩弹塑性应力重分布特点、塑性区厚度、围岩抗剪强度、围岩构造特点等因素来确定。 ⑤以乌鞘岭隧道为例，介绍了高地应力软弱隧道采用预应力锚索作为初期支护的方案设计方法。
[Abstract]:Rock and soil anchoring can change the surrounding rock of underground engineering from load to part of supporting structure, exert the bearing capacity of surrounding rock itself to the maximum extent, and maintain the stability of cavern with smaller supporting force. At present, there is no systematic design theory and calculation method for prestressed cable support in underground engineering. Based on the background of prestressed anchor cable support in underground engineering, this paper studies the principle, design theory, calculation method and determination method of key design parameters of prestressed anchor cable in underground engineering. It provides a scientific theoretical basis for the design of prestressed Anchorage cables in underground caverns. The main contents of this thesis are as follows: The main contents are as follows: 1. Combining with the deformation mechanism of soft surrounding rock, large span tunnel, high ground stress surrounding rock and the action mechanism of anchoring cable active anchor support design, this paper mainly starts from two angles: the stability of surrounding rock and the deformation control of surrounding rock in underground engineering. The elastoplastic analysis of surrounding rock of cavern is carried out. 2 based on the elastic-plastic analysis of weak and broken rock and the principle of active anchoring of anchor cable, the elastoplastic deformation, deformation region, group anchor mechanism and active anchoring mechanism of surrounding rock of cavern are studied and analyzed, which is the stability analysis and evaluation of surrounding rock of cavern. The method of cable arrangement, the determination of cable length and the determination of anchoring distance provide theoretical basis. (3) the method of determining the external load of anchor cable and the anchor force in soft rock is put forward. Based on the elastoplastic analysis of surrounding rock, the supporting force required by the surrounding rock stability criterion can be obtained, and the maximum allowable convergence value of surrounding rock can be determined by the engineering analogy experience method. Then the supporting force needed to meet the requirements of surrounding rock deformation of the cavern is obtained. According to the support force which meets the stability of surrounding rock and the control requirement of surrounding rock deformation, it is regarded as the external load of anchor cable support design. Finally, according to the influence depth of surrounding rock deformation under the condition of active anchoring of anchor cable should be greater than the thickness of loose zone of surrounding rock, it is determined whether the anchoring force of anchor cable is reasonable or not, according to whether the anchor force of anchor cable meets the requirements of existing code, and so on. Determine the main design parameters of the anchor cable. 4. The method of determining anchor length in underground engineering is put forward. The anchoring length includes the length of the anchoring section and the length of the free section, in which the length of the anchoring section of the anchor cable passes through the cementing strength of the cemented material and surrounding rock of the cavern, the cementation strength between the cementing material and the cable reinforcement, the form of the anchoring section, the safety factor, The length of free section of anchor cable is determined by the characteristics of elastic-plastic stress redistribution of surrounding rock, thickness of plastic zone, shear strength of surrounding rock, structural characteristics of surrounding rock, etc. 5 taking Wushaoling tunnel as an example, this paper introduces the scheme design method of using prestressed anchor cable as initial support for soft tunnel with high ground stress.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.7

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