堆积层滑坡微型桩加固设计体系研究

发布时间：2018-01-06 15:04

本文关键词：堆积层滑坡微型桩加固设计体系研究　出处：《西安工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：微型桩是加固滑坡的一种小型支挡措施,其桩径一般不大于300mm。这种小直径桩与传统支挡结构相比具有非开挖施工、对桩身周围土体扰动较小、布设位置灵活、施工速度快和经济性好等许多优点,其在浅层堆积层滑坡中应用越来越多。但目前微型桩加固滑坡的理论研究远远滞后于其在实际工程中的应用,更没有得到大面积的推广,这是因为目前还没有学者针对微型桩提出详细的设计体系。所以,为了得出微型桩的加固机理和设计体系,本文针对浅层堆积层滑坡,主要进行以下研究工作并得出相应结论:1)根据弹塑性力学中桩-土变形相协调的原理,分析了土体在桩排间的传力机理,分析微型桩的加固机理,综合对比后采用传递系数法确定滑坡推力,结合普通抗滑桩计算方法、悬臂桩法及等效法进行微型桩内力计算,确定其水平承载力、抗弯承载力及抗剪能力。2)通过收集资料并整理,按照设计计算方法原理的不同,将微型桩设计体系分为极限平衡法、曲线法、等效截面法、软件法、等效抗弯刚度法以及不均匀系数法,并从优缺点、适用条件等角度对各方法进行了综合比较研究。通过已完成的模型试验,对比不同试验工况,提出了微型桩群的三种破坏形态,分别为群桩破坏、单桩破坏和局部破坏。3)结合弹塑性理论和模型试验结果分析,归纳出了微型桩的设计原则,即合理桩间距宜为8～12d,合理排间距宜为10d左右,此范围不仅能有效发挥自身抗滑力还能使桩间土拱发挥最优效应;桩体锚固深度以1/3～2/5桩长最佳;桩周土体较密实时,群桩宜采用排列形布设,土体较疏松时,群桩宜采用梅花形布设;群桩桩顶须设置连系梁,既限制桩顶位移又可使桩身受力更均匀饱满;依据实际降雨情况,设置相应排水系统。4)以陕西省勉县土关铺乡卓笔村的黄土滑坡为例,针对当地的自然环境状况,在分析滑坡工程地质环境条件、变形破坏模式、诱发因素、形成机制的基础上,确定了微型桩设计方案。并从环保性、安全性、适用性、经济性、工期及施工因素6大方面采用模糊层次分析法对设计方案做了综合评价,最终根据最大隶属度原则确定使用微型桩加固浅层堆积层滑坡的技术经济性良好。
[Abstract]:Micro pile is a kind of small supporting measure to reinforce landslide, its pile diameter is not more than 300mm. compared with traditional retaining structure, this kind of small diameter pile has no excavation construction and less disturbance to the soil around pile body. There are many advantages such as flexible location, fast construction speed and good economy. It is more and more used in shallow pile landslide. However, the theoretical research of micro-pile reinforcement landslide is lagging far behind its application in practical engineering, and has not been widely spread. This is because no scholars have proposed a detailed design system for micro-pile. Therefore, in order to obtain the reinforcement mechanism and design system of micro-pile, this paper aims at shallow pile landslide. According to the principle of the coordination of pile and soil deformation in elastoplastic mechanics, the mechanism of soil force transfer between piles and rows is analyzed, and the reinforcement mechanism of micro-pile is analyzed. After comprehensive comparison, the landslide thrust is determined by transfer coefficient method, combined with common anti-slide pile calculation method, cantilever pile method and equivalent method to calculate the internal force of micro-pile to determine its horizontal bearing capacity. According to the principle of design and calculation, the design system of micro-pile is divided into limit equilibrium method, curve method, equivalent section method and software method. The equivalent flexural stiffness method and the non-uniform coefficient method are compared and studied comprehensively from the point of view of the advantages and disadvantages and the applicable conditions. Through the completed model tests, the different test conditions are compared. In this paper, three kinds of failure modes of micro-pile group are put forward, which are group pile failure, single pile failure and local failure .3. the design principle of micro-pile is concluded by combining elastic-plastic theory and model test results. The reasonable spacing of piles should be 812 days, and the reasonable spacing of rows should be about 10 days. This range can not only give full play to its own anti-slide force, but also make the soil arch between piles play the optimal effect. The best anchoring depth is 1 / 3 / 2 / 5 pile length; When the soil around the pile is dense, the pile group should be arranged in the shape of arrangement, and when the soil is loose, the pile group should be arranged in the shape of plum blossom. Connecting beam should be set on the top of pile, which not only limits the displacement of pile top but also makes the force of pile body more uniform and full. According to the actual rainfall situation, set up the corresponding drainage system .4) take the loess landslide in Zhuobi Village, Tuguanpu Township, Mian County, Shaanxi Province as an example, analyze the landslide engineering geological environment condition in view of the local natural environment condition. On the basis of deformation failure mode, induced factors and formation mechanism, the design scheme of micro-pile is determined, and from the aspects of environmental protection, safety, applicability and economy. The fuzzy analytic hierarchy process (FAHP) is used to evaluate the design scheme in 6 aspects of construction time and construction factors. Finally, according to the principle of maximum membership degree, it is determined that the technique and economy of using micro-pile to reinforce shallow layer landslide is good.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1;P642.22

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