双排桩梁、板联系结构的模型试验研究

发布时间：2018-10-23 20:17

【摘要】：双排桩作为一种新型的深基坑支护体系最早出现于上个世纪80年代末期,由于研究起步较晚,目前对双排桩的受力机理国内外还没有统一的计算模式,仍处于半理论半经验状态。本人在前人的的研究基础上,将双排桩的研究范围扩大,结合工程实例,将现场双排桩按比例缩小至室内模型试验,通过模型试验及有限元模拟对采用梁和板两种不同联系结构的双排桩进行了较系统,较深入的研究,分析得出哪种联系结构综合效益更高,主要研究成果如下： (1)通过室内模型试验,分析研究在前后排桩间距分别取4d、5d、6d的条件下,对于采用梁、板两种联系结构形式的双排桩支护结构在桩顶位移、桩身变形及土压力分布方面的不同变化情况。试验结果表明：梁、板联系结构形式的双排桩桩顶位移累计变化值都随着基坑开挖深度的增加而增加；采用板联系结构的双排桩桩顶位移累计变化值略小于梁联系结构的双排桩桩顶位移累计变化值；两种联系结构桩顶位移累计变化值均随着前后排桩间距的增大而减小。开挖至坑底标高时,梁联系结构的前排桩桩身正负弯矩值均小于板联系结构；后排桩则相反,梁联系结构大于板联系结构；两种联系结构形式的双排桩桩身弯矩均随前后排桩间距增大而增大；前后排桩间的土压力,由于受桩的影响较大,实测土压力分布规律不好,试验中实测桩间土压力随开挖深度的增加呈递减趋势。 (2)结合工程实例,采用大型有限元软件ABAQUS结合工程实例对模型试验及工程现场基坑开挖过程进行计算模拟,分析两种联系结构的双排桩支护结构体系在桩顶位移、桩身弯矩及土压力分布的不同情况,模拟得出结论与室内模型试验结论基本一致,通过工程实测数据与数值模拟成果进行分析对比,验证了本文结果的合理性。
[Abstract]:As a new type of deep foundation pit supporting system, double-row pile was first found in the late 1980s. Due to the late start of the research, there is no unified calculation model for the stress mechanism of double-row pile at home and abroad. It is still in a semi-theoretical and semi-empirical state. On the basis of previous research, I expand the research scope of double-row pile, combining with engineering example, reduce the field double-row pile proportionally to indoor model test. Through the model test and finite element simulation, the double row piles with two different connection structures of beam and plate are studied systematically and deeply, and it is concluded that which kind of connection structure has better comprehensive benefit. The main research results are as follows: (1) through indoor model test, the displacement of double-row pile supporting structure with beam and plate on the top of pile is analyzed and studied under the condition that the distance between front and rear piles is 4 days or 5 days or 6 days, respectively. Different variation of pile deformation and earth pressure distribution. The experimental results show that the accumulative variation values of the displacement of double-row piles in the form of beam-plate connection structure increase with the increase of excavation depth. The accumulative variation value of the displacement at the top of the double-row pile with plate connection structure is slightly smaller than that of the double-row pile structure with the beam connection structure, and the accumulative variation value of the pile top displacement of the two kinds of connection structure decreases with the increase of the distance between the two rows of piles. When excavated to the bottom elevation, the positive and negative moment values of the front row pile body are smaller than that of the plate connection structure, while the back row pile is opposite, the beam connection structure is larger than the plate connection structure. The bending moment of double row piles with two kinds of connection structures increases with the increase of the distance between the two rows of piles, and the earth pressure between the two rows of piles is influenced greatly by the piles, so the distribution law of the measured earth pressure is not good. The measured soil pressure between piles decreases with the increase of excavation depth. (2) combined with engineering example, the model test and excavation process of foundation pit on site are calculated and simulated by using large-scale finite element software ABAQUS and engineering example. By analyzing the different distribution of pile top displacement, pile bending moment and earth pressure between two kinds of double row piles supporting structure, the simulation results are basically consistent with the conclusion of indoor model test. The rationality of the results is verified by the analysis and comparison between the measured data and the numerical simulation results.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU473.1

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