基于桩土相互作用的抗滑桩改进模式三维数值模拟研究

发布时间：2018-05-07 12:48

本文选题：滑坡 + 抗滑桩　；参考：《天津大学》2014年博士论文

【摘要】：鉴于山体滑坡造成的巨大经济损失和人员伤害,采用抗滑桩来加固边坡为工程界常用的工程对策,同时不断出现新的抗滑桩类型。本文总结了滑坡灾害发生的危险性与危害性及抗滑桩在滑坡灾害治理中的研究进展,提出并研究了目前抗滑桩设计及计算中存在的几个问题。鉴于抗滑桩与土相互作用的复杂性,针对目前抗滑桩工程常用的极限平衡计算方法难以考虑抗滑桩与土相互作用的问题,本文借助ABAQUS有限元软件,通过结合工程实例,对不同型式的抗滑桩对边坡的加固效果进行了相关三维数值模拟,对抗滑桩作用下边坡及桩身的应力应变规律进行了归纳分析,在此基础上探讨了不同桩型的抗滑机理和加固效果,得出了一些创新性的有益的结论,为抗滑桩工程设计提供了理论依据及应力应变参考规律。本文的主要研究内容及创新点如下:1、常规抗滑桩设计计算难以考虑桩土相互作用,因此做了一些简化的假定。本文考虑桩土相互作用,以实际工程中常见的1.5m×2m的抗滑桩(对应的等代截面面积的圆截面桩桩径为1.96m)为例,通过三维数值分析,详细探讨了边坡加固工程中的桩身土压力分布型式、桩周土体位移等值线特点及边坡稳定系数与桩间距的关系、桩顶脱开变形、边坡塑性变形、桩身内力、桩身位移等设计中的关键因素。2、遇到大型、深层、下滑力大的滑坡,常规抗滑桩往往抗弯、抗剪承载力不足。当抗滑桩加固范围内有桥梁等对于工后位移有严格要求的结构物,而常规“抗滑桩一般允许有较大的变形”,即使桩身承载能力达到要求也难以满足工后位移的容许要求。本文针对这两个问题,以实际工程实例为依托,在寻求更大承载能力、更小桩身位移的抗滑桩型式方面做出了尝试和努力。通过三维数值模拟算例,详细探讨了门型桩的适用优点、适用的工程环境、门型桩前后桩距与边坡稳定系数的关系、门型桩前后桩距与桩身应力应变的关系以及联系梁结构刚度对于桩身内力的影响等。3、微型桩有常规大尺寸的抗滑桩不可比拟的某些优势,在工程实践中有较好的发展,但是对于微型抗滑桩的作用机理缺乏系统全面的认识,还没有形成一种较为成熟的、广为认可的设计计算理论。本文通过详细的三维数值算例,探讨了微型桩群的桩径、桩与潜在滑动面的夹角、微型桩群的布置间距、布置方式等设计中的关键因素对于边坡加固的影响。然后通过一个管桩加固运营中的高速公路的塌陷滑移边坡抢险工程实例验证了微型桩在施工场地受限、扰动受限、工期要求紧的特殊工点具有较好的使用效果。4、在结构工程上,预应力技术发展很成熟,而在岩土工程的支挡工程中,预应力技术的使用较少。采用竖向桩身预应力技术,提高抗滑桩抗弯能力同时减少桩身截面尺寸,在边坡抗滑桩设计工程中值得关注。此类研究文献非常少,本文通过详细的三维预应力钢筋混凝土数值模拟算例,按照工程设计惯用的配筋方法配筋,分析了预应力钢筋混凝土抗滑桩与常规钢筋混凝土抗滑桩在桩身、预应力钢筋、主体受拉钢筋、架立钢筋、受压侧钢筋的应力应变规律,以及两者对于边坡稳定贡献方面的差异。
[Abstract]:In view of the huge economic losses and personnel injuries caused by landslides, the use of anti slide piles to reinforce the slope is a commonly used engineering countermeasure, and new type of anti slide pile is constantly emerging. This paper summarizes the risk and harmfulness of the landslide disaster and the research progress of the anti slide pile in the treatment of landslide disaster, and puts forward and studies the present research. In view of the complexity of the design and calculation of anti slide pile, in view of the complexity of the interaction of anti slide pile and soil, it is difficult to consider the interaction between anti slide pile and soil for the common limit equilibrium calculation method commonly used in the anti slide pile engineering. In this paper, ABAQUS finite element software is applied to the slope of different types of anti slide piles to the slope. The three dimensional numerical simulation of the reinforcement effect is carried out. The stress and strain law of the slope and the pile body under the action of the sliding pile is summarized and analyzed. On this basis, the anti sliding mechanism and reinforcement effect of different pile types are discussed, and some innovative and useful conclusions are obtained, which provide the theoretical basis and stress and strain for the design of anti slide pile engineering. The main contents and innovation points of this paper are as follows: 1, it is difficult to consider the interaction between pile and soil in the design and calculation of conventional anti slide pile. Therefore, some simplified assumptions are made. In this paper, the interaction of pile and soil is considered, and the common 1.5m * 2m anti slide pile in practical engineering is taken as an example. After three dimensional numerical analysis, the distribution pattern of pile body pressure in the slope reinforcement project, the characteristics of the equivalent line of soil displacement and the relationship between the slope stability coefficient and the pile spacing, the key factors in the design of the pile top deforming, the plastic deformation of the slope, the internal force of the pile, the displacement of the pile body, and so on,.2, are encountered in the large, deep and gliding landslide. The conventional anti slide pile is often bent and has insufficient shear bearing capacity. There are bridges, such as bridges and other structures which have strict requirements for post work displacement in the scope of anti slide pile reinforcement, and the conventional "anti slide pile generally permits large deformation". Even if the bearing capacity of the pile is reached, it is difficult to meet the allowable requirements of post working displacement. This paper is aimed at these two problems. On the basis of practical engineering examples, a trial and effort has been made in the search for the type of anti slide pile with greater bearing capacity and smaller pile displacement. Through a three-dimensional numerical simulation example, the application advantages of the portal type pile, the applicable engineering environment, the relationship between the front and rear pile spacing of the gate type pile and the slope stability coefficient, the distance between the front and rear piles of the gate type pile and the pile are discussed in detail. The relationship between the stress and strain of the body and the influence of the stiffness of the connecting beam on the internal force of the pile, and so on,.3, the micro pile has some advantages unparalleled with the conventional large size anti slide pile, and has a good development in the engineering practice. However, the lack of a comprehensive understanding of the mechanism of the action mechanism of the micro anti slide pile has not formed a more mature and wide range. Through a detailed three-dimensional numerical example, this paper discusses the influence of the key factors in the design of the pile diameter, the angle between the pile and the potential sliding surface, the layout space of the micro pile group, the layout method and other key factors on the slope reinforcement. Then, the collapse slip of the highway in the operation is strengthened through a pipe pile. The example of the slope emergency project proves that the special work point of the mini pile is limited in the construction site, the disturbance is limited and the special work point required for the time limit has a good use effect.4. In the structural engineering, the development of the prestress technology is very mature, while in the retaining engineering of the geotechnical engineering, the prestress technology is less used. The vertical pile body prestress technology is adopted to improve the resistance. The anti bending capacity of the slide pile reduces the size of the cross section of the pile and is worthy of attention in the design of slope anti slide pile. The literature of this kind of research is very few. In this paper, a detailed numerical example of three-dimensional prestressed reinforced concrete is used to analyze the mixing of the prestressed concrete anti slide pile and the conventional steel bar in accordance with the reinforcement method used in the engineering design. The stress and strain law of the pile body, prestressed reinforcement, the main body of the reinforced bar, the stand bar, the reinforced bar, and the difference between the two sides to the slope stability.

【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU473.1

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