差异化组合布锚支护方式对边坡稳定性影响及其工程应用

发布时间：2018-01-18 01:17

本文关键词：差异化组合布锚支护方式对边坡稳定性影响及其工程应用　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：为寻求边坡锚杆布设的优化形式,拟采用差异化锚长组合方式进行支护。首先探讨在边坡不同位置单独布锚,得出其对边坡整体稳定性的贡献存在显著差异,由此引出并强调边坡层位的作用。另外考虑到对锚杆长度进行差异组合在经济上更为合理,由此将边坡锚杆组布设成“长-中-短型”、“中-长-短型”、“短-长-中型”三种组合形式,通过分析安全系数差异、锚杆轴力比重和滑动面位置等变化情况,研究布置方式的变化对边坡稳定性的影响。然后采用坡顶超载这一特定布载形式来检验各组合加固边坡后的稳定性。最终,将前述内容所得结论应用至一三维锚杆(索)框格梁加固边坡的实例中。本文研究成果主要如下:1、在组合布锚情况下,存在整体最佳锚固角θopt与层位有效锚长Leff,安全系数差异与滑动面位置的主控因素均随锚固角在各层位间不断转移,边坡破坏模式随锚固角增大由深层滑动突变为浅层滑动;当各层锚杆组采用单层布锚下的最佳锚固角进行组合布设时,加固效果一般,存在“组合-群锚效应”,此时对各层锚杆组按小角度岔开布设为宜。2、在坡顶超载作用下,“短-长-中型”组合仍是最优组合形式。而其特殊性体现在超载施加于坡顶,与坡顶层布置锚杆类型(锚长)有关:坡顶层布置的锚杆越长,安全系数在超载值较大时下降幅值越小;主控边坡滑动面的层位(或锚杆组)的锚固角范围出现变动。3、采用锚杆(索)框格梁组合支护三维边坡的稳定性明显提高。框格梁liner单元能很好的反映预应力的施加,整体破坏形式基本不会发生,次级滑动面消失。预应力锚索具有反向锚固作用,充分发挥深部稳定岩层的自稳能力,在一定程度上达到抑制了坡面卸荷变形效果;开挖边坡支护与否稳定性差异大,支护边坡的剪应变增量比未支护时显著降低,大大地减小了剪切破坏的可能。4、边坡开挖与预应力锚索框格梁加固,实质上是一个应力释放-卸荷回弹、应力补偿的过程。
[Abstract]:In order to find the optimal form of the slope anchor placement, the differential anchor length combination is used to support the slope. Firstly, the individual anchor placement in different positions of the slope is discussed, and its contribution to the overall stability of the slope is found to be significantly different. In addition, considering that the difference of bolt length is more reasonable in economy, the bolt group of slope is arranged as "long, medium-short" and "medium-long-short". By analyzing the difference of safety factor, axial force specific gravity of anchor rod and the position of sliding surface, the three combination forms of "short, long and medium" are analyzed. The influence of the change of layout on the slope stability is studied. Then the overloading on the top of the slope is adopted to test the stability of the slope after the combined reinforcement. The above conclusions are applied to an example of reinforcement of slope with three dimensional anchor bar (cable) frame lattice beam. The main research results of this paper are as follows: 1, in the case of combined anchor placement. There exists the overall optimum anchoring angle 胃 opt and the effective anchor length Leff. the difference of safety factor and the main controlling factors of the sliding surface position are all transferred with the anchoring angle among the layers. The failure mode of slope changes from deep sliding to shallow sliding with the increase of anchoring angle. When the best Anchorage angle under single-layer anchor is adopted for each layer of anchor group, the reinforcement effect is general and there is "combination-group anchor effect". At this time, it is appropriate for each layer of anchor group to be arranged at a small angle. Under the action of slope top overload, "short-long-medium" combination is still the optimal combination form, and its particularity is that overload is applied to the top of the slope. It is related to the type of anchor (length of anchor) arranged at the top of the slope: the longer the anchor is arranged in the top of the slope, the smaller the decreasing amplitude of the safety factor is when the overload value is larger; The Anchorage angle range of the slide surface of the main control slope (or Anchorage group) varies by 3. 3. The stability of three-dimensional slope supported by bolting (cable) frame girder combination is obviously improved. The liner element of frame lattice beam can reflect the application of prestressing force, and the whole failure form will not occur. The secondary sliding surface disappears. The prestressed anchor cable has the function of reverse anchoring, fully exerts the self-stability ability of the deep stable rock, and to a certain extent, it can restrain the unloading deformation of the slope surface. The stability of excavation slope is different, the increment of shear strain is significantly lower than that without support, the possibility of shear failure is greatly reduced, the slope excavation and reinforcement of prestressed cable frame girder. Essentially, it is a process of stress release-unloading rebound and stress compensation.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU476;TU753

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