膨胀土滑坡形成机理及治理措施研究

发布时间：2018-07-15 16:49

【摘要】：近年来,滑坡在高速公路及高速铁路工程中所占的比例越来越大,因而诸多学者对滑坡形成机理及治理措施的研究越来越多,特别是对特殊土体滑坡稳定性的研究更是久盛不衰。本文以十天高速汉中西勉县检测站膨胀土滑坡为背景,对膨胀土多滑坡的治理进行分析研究,通过锚索抗滑桩的变形特点、测斜孔的变化特点以及地表位移的变化特点来制定该地区滑坡的治理措施。最后,利用Midas/GTS NX软件对该滑坡进行支护分析,通过支护结果分析优化模型,以便在最经济的条件下达到最好的防护效果。本文主要研究内容有如下几个方面:(1)查阅相关文献,了解有关膨胀土滑坡的研究现状,明确膨胀土自身的工程特性和影响膨胀土产生滑坡的因素以及膨胀土滑坡的失稳机理。(2)根据现场实际情况制定滑坡监测方案。现场选取两条主轴断面进行深孔位移监测,预设监测钻孔6个,孔深40m,通过监测数据绘制S-W-T图,对比分析各钻孔孔口位移和水位埋深随时间的变化规律以及各钻孔水平位移随深度的变化规律。在锚索抗滑桩桩背一侧布设土压力盒,测出抗滑桩桩后土压力值;在抗滑桩受拉和受压侧主筋上对称设置钢筋计测出抗滑桩主筋内力,从而可以反算出抗滑桩桩身弯矩。(3)根据现场实际土层及支护情况用MIDAS GTS建立二维有限元模型,得出抗滑桩在单排桩、双排桩、三排桩支护情况下桩身水平位移分别为4.71cm、4.48cm、4.20cm。同时也得出桩身弯矩随深度的分布规律,以及潜在滑裂面的位置和加固后的滑坡安全系数。将计算得到的抗滑桩桩身水平位移和桩身弯矩与现场实测结果进行对比,两者结果基本一致,可见合理的有限元模型可以有效的描述现场滑坡在施工过程中内力和变形机理。(4)最后通过改变抗滑桩的排数,研究了在不同抗滑桩设计方案下,滑坡在施工过程中的受力及变形机理。最后得比各抗滑桩设计方案下的安全系数分别为1.1、1.15、1.35、1.61,得知不设抗滑桩时的安全系数最低,设置三排桩的安全系数最高,考虑到实际的经济性,设置两排桩最为合理。
[Abstract]:In recent years, the proportion of landslide in expressway and high-speed railway projects is increasing, so many scholars have studied more and more landslide formation mechanism and treatment measures. Especially the study on the stability of special soil landslide is even more prosperous. In this paper, based on the landslide of expansive soil at the test station in Mian County, Hanzhong County, ten days high speed, the treatment of multiple landslide of expansive soil is analyzed and studied, and the deformation characteristics of anti-slide pile with anchor cable are analyzed and studied in this paper. The change characteristics of slanting hole and the change of surface displacement are used to make the treatment measures of landslide in this area. Finally, Midas / GTS NX software is used to analyze the landslide support, and the model is optimized by analyzing the supporting results, so as to achieve the best protective effect under the most economical conditions. The main contents of this paper are as follows: (1) referring to the relevant literature, to understand the research status of expansive soil landslide, The engineering characteristics of expansive soil itself, the factors influencing the landslide of expansive soil and the instability mechanism of expansive soil landslide are clarified. (2) according to the actual situation on the spot, the landslide monitoring scheme is established. Two main shaft sections were selected to monitor the displacement of deep hole. Six holes were preset monitored, and the hole depth was 40m. The S-W-T map was drawn by monitoring data. The variation law of hole displacement and water level depth with time and horizontal displacement with depth of borehole are compared and analyzed. The earth pressure box is arranged on the back side of the anchor cable anti-slide pile to measure the value of the earth pressure after the anti-slide pile, and the internal force of the main reinforcement of the anti-slide pile is measured by symmetrically setting the reinforcing bar on the tension and compression side of the anti-slide pile. Therefore, the bending moment of anti-slide pile can be calculated back. (3) according to the actual soil layer and supporting condition, the two-dimensional finite element model of anti-slide pile is established by Midas GTS, and the horizontal displacement of anti-slide pile in single row pile, double row pile and three row pile support is 4.71 cm ~ 4.48 cm ~ (-1) ~ 4.20 cm ~ (-1) respectively. At the same time, the distribution law of pile bending moment with depth, the location of potential slip surface and the safety factor of reinforced landslide are also obtained. The calculated horizontal displacement and bending moment of anti-slide pile body are compared with the measured results, and the results are basically the same. It can be seen that the reasonable finite element model can effectively describe the internal force and deformation mechanism of the landslide in the construction process. (4) finally, by changing the number of anti-slide piles, the different anti-slide pile design schemes are studied. Stress and deformation mechanism of landslide during construction. Finally, the safety factor of each design scheme is 1.1l / 1.15 / 1.35 / 1.61respectively. It is known that the safety coefficient is the lowest when the anti-slide pile is not set, and the safety coefficient of the three rows of piles is the highest. Considering the actual economy, it is most reasonable to set up two rows of piles.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U418.55

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