椅式桩支挡结构离心模型试验研究

发布时间：2018-06-29 03:06

本文选题：椅式桩支挡结构 + 土工离心模型试验　；参考：《西南交通大学》2015年硕士论文

【摘要】：目前国内外关于陡坡路基的研究十分活跃,陡坡路基支挡结构也向轻型化和组合化方向发展。组合式支挡结构正是在这种形势下出现的,椅式桩支挡结构是具有代表性的组合式支挡结构之一。椅式桩支挡结构由长桩、短桩、横梁及挡板组成,兼有承重和支挡功能。椅式桩支挡结构的受力同其他支挡结构相比差别明显,桩土相互作用较为复杂,在进行结构设计时许多参数是依据经验来选取,难以满足工程设计要求。鉴于此,本文采用理论分析、土工离心模型试验和数值模拟相结合的方法,对椅式桩支挡结构的结构-岩土相互作用、变形和内力分布等进行了较为全面的分析。论文的主要研究成果如下：(1)悬臂段土压力采用库伦主动土压力计算,短桩后土压力为矩形分布的滑坡推力,桩间土压力可简化成静止土压力,短桩前土压力取剩余抗滑力或者被动土压力的1/3,横梁上土压力取纵向跨度范围内土体自重,不考虑横梁下岩土体的作用；(2)椅式桩简化为平面刚架,分解为主桩悬臂段、中部门型区段和桩基锚固段三部分进行考虑,采用结构力学方法进行计算；(3)椅式桩支挡结构内力分布的危险截面分别为长桩悬臂段底部、长桩横梁以下临界处、长桩锚固段中央、横梁最左侧、横梁最右侧、短桩横梁以下临界处和短桩锚固段中央,结构设计中主要针对这七个截面进行计算；(4)数值分析表明,理论计算中采取的土压力计算方法及分布型式是合理并偏于安全的,椅式桩内力的数值分析结果和理论计算结果的分布规律一致,总体上理论值大于数值分析值；(5)土工离心模型试验结果同理论计算和数值分析结果进行对比分析,结果表明结构的土压力分布规律和内力分布规律同理论计算一致,从而理论计算方法的适用性得到验证。
[Abstract]:At present, the research on steep embankment is very active at home and abroad. It is in this situation that the combined retaining structure appears, and the chair pile retaining structure is one of the representative composite retaining structures. Chair pile retaining structure is composed of long pile, short pile, cross beam and baffle. Compared with other retaining structures, the stress of chair pile retaining structure is obviously different, and the pile-soil interaction is more complex. Many parameters are selected according to experience in structural design, so it is difficult to meet the requirements of engineering design. In this paper, the structure-rock soil interaction, deformation and internal force distribution of chair pile retaining structure are analyzed comprehensively by means of theoretical analysis, geo-centrifugal model test and numerical simulation. The main research results are as follows: (1) the earth pressure in the cantilever section is calculated by Coulomb active earth pressure. The earth pressure behind the short pile is a rectangular distribution of landslide thrust, and the earth pressure between piles can be simplified to static earth pressure. The earth pressure in front of the short pile is about 1 / 3 of the residual anti-slide force or the passive earth pressure, and the earth pressure on the beam takes the soil mass in the longitudinal span range without considering the role of the rock and soil under the beam. (2) the chair pile is simplified as a plane rigid frame, which decomposes the cantilever section of the main pile. Considering the three parts of the middle section and the anchor section of pile foundation, the method of structural mechanics is used to calculate. (3) the dangerous sections of the distribution of the internal force of the chair pile retaining structure are respectively the bottom of the cantilever section of the long pile and the critical position below the beam of the long pile. At the center of the long pile Anchorage section, the left side of the crossbeam, the right side of the beam, the critical point below the short pile beam and the center of the short pile Anchorage section, the structural design mainly focuses on the calculation of these seven sections. (4) numerical analysis shows that, The calculation method and distribution pattern of earth pressure adopted in the theoretical calculation are reasonable and safe. The results of numerical analysis of the internal forces of chair pile are consistent with the distribution law of the results of theoretical calculation, and the theoretical value is larger than the value of numerical analysis in general. (5) the results of geotechnical centrifugal model test are compared with those of theoretical calculation and numerical analysis. The results show that the distribution law of earth pressure and internal force of the structure is consistent with the theoretical calculation, thus the applicability of the theoretical calculation method is verified.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U213.1;U416.1

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