微型桩加固浅层堆积层滑坡桩身应力分布规律试验研究

发布时间：2018-03-11 02:32

本文选题：微型桩　切入点：浅层堆积层滑坡　出处：《西安工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国所有类型质灾害中,滑坡比例高达50%以上。陕西省境内滑坡在各种质灾害中更是达到了62.3%比重,而浅层堆积层滑坡在各种类型滑坡中达到了65%,因而开展针对浅层堆积层滑坡加固防止技术有着重大实际意义。随着滑坡灾害加固技术发展,微型桩因非开挖施工、对桩身周围土体扰动较小、桩布设位置灵活,施工速度快和良好经济性等特点,近年来在浅层堆积层滑坡中应用越来越多。但微型桩加固滑坡理论研究远远滞后于微型桩在加固滑坡实际工程中使用情况。本文针对这种现状,以相似原理为理论依据,以框架模型试验为研究手段,对微型桩加固浅层堆积层坡过程中桩身应力分布规律进行研究。试验中通过对单排桩、双排桩、梅花形布设三排微型桩加固浅层堆积层滑坡进行试验,探究合理桩间距、排间距以及微型桩桩顶布设连系梁条件,微型桩在抗滑过程中桩身应力分布规律。通过对5组模型试验实验数据分析,主要得到以下结论：(1)未布设微型桩时,坡顶加载5.6kpa后,滑坡就达到失稳破坏临界阶段,而合理布桩方式三排桩试验中,滑坡达到失稳破坏临滑阶段,坡顶需要施加24.7kpa,由此可以看出微型桩对滑坡稳定程度提高是非常明显,微型桩应用于浅层堆积层滑坡加固治理工程中是切实可行。(2)不同试验工况条件,微型桩最终破坏形态表现出一致性,即滑面附近,滑面以上受荷段桩身向滑体前缘弯曲变形,滑面一锚固段向滑床后缘弯曲变形,滑面上弯曲点之间桩身发生倾斜变形,其余部分桩身未有变形出现,保持为竖直状态。(3)浅层堆积层滑坡治理中,合理桩间距可取8-12d,合理排桩间距可在10d范围内选取,同时在桩顶布设连系梁对桩顶位移限制能起到明显作用。梅花形布设群桩试验中,布设桩顶连系梁分区桩顶位移比未布设连系梁分区桩顶位移降低了25.6%,同时桩身应力在桩身应力分布更加均匀饱满而非仅仅集中在滑面附近。(4)通过对比桩顶位移迅速增长、桩身应力快速增大、桩间土拱破坏桩间土压力开始减小加载时间以及对应坡顶竖向均布荷载,可知,这三种试验现象发展基本是同时发生,因而对于加固之后滑坡稳定性情况,可以通过对桩顶水平位移监测来实现。
[Abstract]:Of all types of natural disasters in China, the proportion of landslides is as high as more than 50%. In Shaanxi Province, the proportion of landslides in all kinds of natural disasters has reached 62.3%. However, the shallow layer landslide has reached 65% in all kinds of landslides, so it is of great practical significance to carry out the reinforcement and prevention technology for the shallow accumulation layer landslide. With the development of landslide disaster reinforcement technology, the micro-pile is constructed without excavation. It has the advantages of less disturbance to the soil around the pile body, flexible placement of the pile, fast construction speed and good economy, etc. In recent years, more and more applications have been made in shallow pile landslide. However, the theoretical study of micro-pile strengthening landslide is far behind the application of micro-pile in the practical engineering of landslide reinforcement. In view of this situation, this paper takes the similarity principle as the theoretical basis. By means of frame model test, the stress distribution law of pile body in the process of reinforcement of shallow accumulation slope by micro pile is studied. In the experiment, single row pile, double row pile, Three rows of miniature piles are arranged in plum blossom shape to reinforce shallow pile landslide. The reasonable pile spacing, row spacing and the condition of connecting beam at the top of micro pile are explored. By analyzing the experimental data of five groups of model tests, the following conclusions are obtained: when the micro-pile is not installed, the landslide reaches the critical stage of instability and failure after loading 5.6kpa at the top of the slope. However, in the test of three rows of piles in reasonable distribution mode, the landslide reaches the stage of instability and failure, and the top of the slope needs to be applied 24.7 kpa.Thus, it can be seen that the micro-pile is very obvious to improve the stability of the landslide. It is feasible to apply micro-pile in the engineering of shallow pile landslide reinforcement and treatment. (2) different test conditions are available. The ultimate failure pattern of micro-pile shows consistency, that is, near the sliding surface, above the sliding surface is subjected to bending deformation of the pile body towards the front edge of the sliding body in the section of pile. The slip surface-Anchorage section bends towards the back edge of the slide bed, the pile body is inclined to deformation between the bending points on the slip surface, and the other part of the pile body does not deform and remains in a vertical state. 3) during the treatment of the shallow accumulation layer landslide, Reasonable spacing of piles can be chosen within 10 days, reasonable spacing of piles can be chosen within 10 days, at the same time, the arrangement of connecting beams on the top of piles can play a significant role in limiting the displacement of the top of piles. The displacement of the top of the pile in the partition section of the connecting beam with the pile top is 25.6 lower than that of the section without the connected beam, and the stress distribution of the pile body is more uniform and full than the stress distribution of the pile body, which is not only concentrated near the sliding surface, but also increases rapidly by comparing the displacement of the top of the pile with that of the non-connected beam. The stress of pile body increases rapidly, and the soil pressure between piles begins to decrease the loading time and the vertical distribution load corresponding to the slope top. It can be seen that these three experimental phenomena basically occur at the same time, so the stability of the landslide after reinforcement occurs. It can be realized by monitoring the horizontal displacement of the pile top.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22;TU473.1

【引证文献】