边坡治理的桩位问题及在重庆疏港大道中的应用

发布时间：2018-10-05 15:47

【摘要】：随着国家经济的迅速增长，公共设施和基础设施建设蓬勃兴起，边坡稳定性分析及治理显得越来越重要。边坡稳定性分析方法有很多，不同的分析方法得出不同的结果。在边坡的治理中，采用抗滑桩治理是常用方法之一。但抗滑桩的纵向位置及桩间距的确定，目前还没一个统一的计算方法。因此对边坡稳定性分析研究及抗滑桩位置的优化布置具有重要意义。边坡稳定性分析方法的研究，国内外在这方面已取得不小成绩。本文针对岩石土体边坡的特性，采用预应力锚索抗滑桩加固边坡，通过比较分析强度折减有限元法和极限平衡法的优缺点，表明强度折减有限元法分析边坡稳定性更合理。针对目前有关土拱效应的研究，桩的间距至今还没有统一的计算方法，本文在前人研究的基础上，对抗滑桩位置的布置进行了深入研究，主要研究成果如下： ①对强度折减有限元法和极限平衡法的优缺点对比分析，结合重庆疏港大道自身的特点，选用强度折减有限元法分析边坡稳定性。 ②采用强度折减法，计算出了抗滑桩纵向最佳位置。通过对土体参数折减计算，得出边坡临界值（安全系数为1）时位移最大区域。在边坡位移最大区域的中部、位移最大区域的底部以及坡脚设置相同的抗滑桩，经比较分析，，得出在位移最大区域的底部打抗滑桩既经济，又安全，施工也方便，效果最好。 ③提出了桩间距与土拱效应的关系，针对抗滑桩间距对土拱影响，提出抗桩间距计算模型。推导了抗滑桩间距计算公式，并分析了抗滑桩间距L，拱高h，内摩擦角，桩宽a、粘聚力c、桩后荷载q之间的相互关系。通过分析计算，在其它因素不变的情况下，桩间距L与a、c成正比例关系，与q成反比例。土拱效应和桩间距的关系为：当桩净间距小于3倍桩宽或大于7倍桩宽时，土拱效应不明显，或者不存在土拱效应；当桩净间距大于3倍桩宽且小于7倍桩宽时，土拱效应明显，且桩间距越大，土拱效应越小。 ④利用自己推导的抗滑桩桩间距计算公式，最终确定抗滑桩位置。 ⑤利用本文确定方法开展了重疏港大道公路边坡稳定性计算，并对比单排桩和双排桩两种设计方案，从安全、经济、施工便利等因素综合分析比较，建议优先选择单排抗滑桩处理边坡。
[Abstract]:With the rapid growth of national economy, public facilities and infrastructure construction flourish, slope stability analysis and management becomes more and more important. There are many methods for slope stability analysis. In slope treatment, anti-slide pile treatment is one of the common methods. However, there is no unified calculation method for determining the longitudinal position and spacing of anti-slide pile. Therefore, it is of great significance to analyze the slope stability and optimize the position of anti-slide pile. The research of slope stability analysis method has made great achievements at home and abroad. According to the characteristics of rock and soil slope, the prestressed anchor cable anti-slide pile is used to reinforce the slope. By comparing and analyzing the advantages and disadvantages of the strength reduction finite element method and the limit equilibrium method, it is shown that the strength reduction finite element method is more reasonable to analyze the slope stability. In view of the current research on soil arch effect, there is no uniform calculation method of pile spacing up to now. Based on the previous studies, this paper makes a deep study on the location of anti-slide piles. The main research results are as follows: 1 comparing and analyzing the advantages and disadvantages of the strength reduction finite element method and the limit equilibrium method, combining the characteristics of Chongqing Shugang Avenue, the strength reduction finite element method is selected to analyze the slope stability. 2 the optimum longitudinal position of anti-slide pile is calculated by strength reduction method. By calculating the soil parameters, the maximum displacement area is obtained when the slope critical value (safety factor is 1). In the middle of the maximum displacement region of the slope, the same anti-slide pile is set at the bottom of the maximum displacement area and at the foot of the slope. By comparison and analysis, it is concluded that the anti-slide pile at the bottom of the maximum displacement area is economical, safe, convenient for construction and the best in effect. (3) the relationship between pile spacing and soil arch effect is put forward, and the calculation model of anti-pile spacing is put forward in view of the influence of anti-slide pile spacing on soil arch. The formula for calculating the distance between anti-slide piles is derived, and the relations among the spacing of anti-slide piles L, the height of arch h, the angle of internal friction, the width of pile a, the cohesion c and the load Q behind the pile are analyzed. Through analysis and calculation, under the condition that other factors are not changed, the pile spacing L is proportional to AGC and inversely proportional to Q. The relationship between soil arch effect and pile spacing is as follows: when the net spacing of piles is less than 3 times of pile width or greater than 7 times of pile width, the soil arch effect is not obvious or there is no soil arch effect, and when the net spacing of piles is more than 3 times of pile width and less than 7 times of pile width, The soil arch effect is obvious, and the larger the pile spacing is, the smaller the soil arch effect is. Finally, the position of anti-slide pile is determined by the formula of pile spacing derived by ourselves. 5. The stability calculation of the highway slope is carried out by using the method determined in this paper, and compared with the two design schemes of single row pile and double row pile, comprehensive analysis and comparison are made from the factors of safety, economy, construction convenience and so on. It is suggested that single row anti-slide pile should be selected as a priority for slope treatment.
【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】：U416.14

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