吸入式组合桩模型试验和分析

发布时间：2018-05-06 12:42

本文选题：吸入式组合桩 + 大尺度模型试验　；参考：《太原理工大学》2017年硕士论文

【摘要】：随着海洋开发不断向深海进行,各种深海浮式结构的安全、稳定、高效的运行都离不开安全经济的系泊系统,而锚泊系统的安全运行离不开牢固可靠的深水锚固结构。吸入式组合桩是针对单体桩稳定性、可调性较差这些缺点而应运而生,吸入式组合桩具备了单体桩所不具有的整体承载能力高的特点,还使组合桩的几何尺寸变得符合施工原理,减少耗费的材料和桩体重量,最终提高运输的可行性,降低工程的成本。吸入式组合桩的经济性和适应性将使其具有相对较高的工程应用上的可行性。本文将对不同的长径比和桩间距在饱和砂质土壤中吸入式组合桩的荷载性质进行大尺度试验分析,同时通过改变荷载作用角度,并结合了单桩的相关试验,为今后的吸入式组合桩作为深水锚固结构的设计和施工提供理论上的一些依据和技术上的相关支持。本文的试验研究结果如下:在沉桩过程中,桩体受到的阻力随着沉桩深度的增加呈现非线性增长,且贯入阻力增长速度也逐渐增大;组合桩受到的阻力与桩间距呈现负相关。在沉桩过程中,组合桩阻力与单桩阻力的比值随着深度的增加而增加。本文根据沉桩过程地试验数据,并参考相关文献提出单桩和组合桩沉桩阻力拟合计算方法。在本文中,将传递荷载的钢索与水平面的夹角作为施加到桩体上的斜向荷载的荷载角。通过对斜向荷载作用下的组合桩的简化力学模型分析得到的结论有:当施加到荷载点的荷载的角度较小时,组合桩在斜向荷载作用下主要表现处在水平方向上的位移,后仰效果不是很明显。当荷载角度逐渐变大时,施加到组合桩上的力偶效果逐渐增强,组合桩在荷载作用下的后仰效果逐渐变得明显;组合桩上任意点的位移是整体位移和组合桩变形的综合结果,在计算组合桩局部点的位移时需要分析桩体的整体位移和桩体的局部变形,并且两者之间存在相互影响的耦合作用。通过对试验数据的分析得到的结论有:对组合桩简化力学模型的分析结论得到了验证;在不同的荷载角度的作用下,只通过单一点的位移监测无法准确的判断桩体是否达到极限荷载,因此在制定桩体基础破坏时位移标准时应该将荷载角度因素考虑在内;组合桩受到极限荷载时的位移比较小,但是随着荷载角度的增大,极限荷载时的位移量会逐渐增大;当组合桩的荷载作用点位于桩前腿2/3埋深时,且斜向荷载小于45°时,荷载角度越小,组合桩的极限荷载越大。试验表明,通过测量记录SAA系统各测量点的位置变化数据来计算桩体的位移变形,使的本试验在试验过程中能够计算出除了露出土体表面的桩头的位移变形,还能计算出埋入土体的桩体的位移变形,因此使试验能够计算得到更为全面的关于桩体位移变形的试验数据,为将来类似的相关研究提供借鉴依据。
[Abstract]:With the continuous development of the ocean to the deep sea, the safety, stability and efficient operation of various deep-sea floating structures can not be separated from the safe and economical mooring system, while the safe operation of the mooring system can not be separated from the solid and reliable deep-water anchoring structure. The suction composite pile comes into being in view of the shortcomings of single pile stability and poor adjustability. The suction composite pile has the characteristics of high overall bearing capacity which the single pile does not have. It also makes the geometric dimension of the composite pile conform to the construction principle, reduces the material and pile weight, improves the feasibility of transportation and reduces the cost of the project. The economy and adaptability of suction composite pile will make it more feasible in engineering application. In this paper, the load properties of inhaled composite piles with different ratio of length to diameter and pile spacing in saturated sandy soil are analyzed on a large scale. At the same time, by changing the loading angle and combining with the related tests of single pile, It provides some theoretical basis and technical support for the design and construction of suction composite pile as a deep water Anchorage structure in the future. The experimental results are as follows: in the process of pile-sinking, the resistance of pile body increases non-linear with the increase of pile-sinking depth, and the growth rate of penetration resistance increases gradually, and the resistance of composite pile is negatively correlated with pile spacing. In the process of pile sinking, the ratio of composite pile resistance to single pile resistance increases with the increase of depth. Based on the ground test data of pile-sinking process and referring to relevant literatures, a method for calculating the resistance of single pile and composite pile is proposed in this paper. In this paper, the angle between the transfer cable and the horizontal plane is taken as the load angle of the oblique load applied to the pile. Through the analysis of the simplified mechanical model of composite pile under oblique load, the conclusions are as follows: when the load angle applied to the load point is small, the displacement of composite pile under oblique load is mainly in horizontal direction. Backward effect is not very obvious. When the load angle becomes larger, the effect of couple applied to the composite pile is gradually enhanced, and the displacement of any point on the composite pile is the comprehensive result of the whole displacement and the deformation of the composite pile. It is necessary to analyze the global displacement of the pile and the local deformation of the pile when calculating the displacement of the local point of the composite pile, and there is a coupling effect between the two. The conclusions obtained from the analysis of the test data are as follows: the conclusion of simplified mechanical model of composite pile is verified, and under the action of different load angles, The displacement monitoring of a single point can not accurately judge whether the pile reaches the ultimate load or not, so the load angle factor should be taken into account in the formulation of the displacement standard when the pile foundation is destroyed, and the displacement of the composite pile subjected to the ultimate load is relatively small. However, with the increase of the load angle, the displacement of the ultimate load will gradually increase. When the load point of the composite pile is 2 / 3 of the buried depth of the pile front leg, and the oblique load is less than 45 掳, the smaller the load angle is, the greater the ultimate load of the composite pile is. The experiment shows that the displacement and deformation of pile body can be calculated by measuring and recording the position change data of each measuring point in SAA system, so that the displacement and deformation of pile head except the exposed soil surface can be calculated in this experiment. The displacement and deformation of pile embedded in soil can also be calculated, so that more comprehensive experimental data on displacement and deformation of pile can be obtained by the experiment, which provides a reference basis for similar related research in the future.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1;P75

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