透水管桩承载性能研究

发布时间：2018-03-03 18:41

本文选题：透水管桩　切入点：开孔规律　出处：《南京工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：静压法沉桩会由于挤土效应,导致孔隙水压力的发挥,透水管桩是一种通过加速超静孔隙水压力消散而减轻挤土效应的新型管桩工艺。在工艺的推广运用过程中,透水管桩由于开孔后的强度降低就成为亟待解决的问题,本文针对透水管桩开孔后的桩身极限抗压能力以及抗弯性能进行研究,得出其具体影响规律,从而进一步指导透水管桩的生产推广。本文就透水管桩开孔后的桩身极限抗压性能以及抗弯性能进行试验研究和ABAQUS有限元数值模拟。主要研究内容和成果如下：(1)进行透水管桩开孔段竖向极限抗压承载性能试验,并建立ABAQUS有限元透水管桩开孔段模型进行试验模拟,研究不同开孔情况对桩体极限抗压强度的影响,归纳开孔后的透水管桩开孔段的桩身极限抗压强度变化规律。(2)进行全尺寸透水管桩与普通管桩抗弯试验,并进行有限元模拟。与普通管桩相比在相同荷载条件下,透水管桩跨中挠度变化较大,混凝土以及钢筋应力较大,混凝土塑性区域发展明显,开裂弯矩降低,但是各项性能差异与普通管桩相比并不明显,还均可以满足规范要求；透水管桩达到极限状态的标志与普通管桩相同,都是裂缝宽度达到1.5mm,此时除了裂缝超过极限状态外管桩并未发生其他破坏,还具有承载能力。透水管桩开孔后其自身均匀产生多个薄弱面,以致裂缝发展可以在其附近发展,而这也分散了应力在普通管桩随着裂缝产生的单一薄弱面的发展,使得其同等荷载下的缝宽小于普通管桩,这就使得在裂缝宽度衡量下,透水管桩的极限弯矩大于普通管桩。(3)对工程实例的分析研究,利用规范对其中桩身竖向承载力标准值和特征值进行计算,与透水管桩降低后的桩身极限抗压强度对比,可以发现,虽然开孔对桩身极限抗压强度有一定的影响,但还是可以满足桩身竖向承载力标准值和特征值发挥。
[Abstract]:Static pressure piling will cause pore water pressure to play due to the compaction effect. Permeable pipe pile is a new type of pipe pile technology, which can reduce the soil squeezing effect by accelerating the dissipation of excess pore water pressure. In the process of popularizing and applying the technology, It is urgent to solve the problem that the strength of permeable pipe pile decreases after opening. In this paper, the ultimate compressive capacity and flexural behavior of the pile body after perforation are studied, and the concrete influence law is obtained. In this paper, the ultimate compressive and flexural properties of the perforated pile are tested and simulated by ABAQUS finite element method. The main research contents and results are as follows: 1). The vertical ultimate compressive bearing capacity test of the perforated section of the permeable pipe pile was carried out. The ABAQUS finite element model of perforated pile is established to study the influence of different hole opening conditions on the ultimate compressive strength of the pile. The ultimate compressive strength variation law of the perforated section of the permeable pipe pile after opening is summarized. The bending tests of the full-size permeable pipe pile and the ordinary pipe pile are carried out, and the finite element simulation is carried out. Compared with the common pipe pile, under the same load conditions, The deflection of permeable pipe pile in the span is changed greatly, the stress of concrete and steel bar is larger, the plastic zone of concrete develops obviously, the cracking moment is reduced, but the performance difference is not obvious compared with the ordinary pipe pile, and all of them can meet the requirements of the code. The mark of reaching the limit state of the permeable pipe pile is the same as that of the ordinary pipe pile. The width of the crack is 1.5 mm. There is no other damage to the pipe pile except that the crack exceeds the limit state. There is also bearing capacity. After the perforation of the permeable pipe pile, it produces a number of weak surfaces evenly, so that the crack development can develop near it, which also distributes the stress in the development of the single weak surface of the common pipe pile with the crack. The joint width under the same load is smaller than that of the common pipe pile, which makes the ultimate bending moment of the permeable pipe pile greater than that of the ordinary pipe pile under the measurement of crack width. The standard value and characteristic value of vertical bearing capacity of pile body are calculated by using the code, and compared with the ultimate compressive strength of pile body after the reduction of permeable pipe pile, it can be found that although the hole has certain influence on the ultimate compressive strength of pile body, But it can satisfy the standard value and characteristic value of vertical bearing capacity of pile body.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU473.1

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