软土地区主动受荷下桥梁群桩基础桩土相互作用研究

发布时间：2018-06-06 17:21

本文选题：软土 + 桩基础　；参考：《西南交通大学》2014年硕士论文

【摘要】：由于软土具有低强度、高压缩性的特点,在软土地区修建高铁一般选用桩基础,但水平荷载下桩基础的承载性能是一个非常复杂的桩土相互作用过程。同时,规范中的m法受众多因素影响,对软土地区横向受荷桩基础进行设计并不能达到预期的效果,存在一定的优化空间。因此本论文针对以上不足综合考虑,采用ABAQUS数值分析手段分别对影响单桩、群桩基础水平承载性能的主要因素进行分析,对比其水平受力特性规律,包括桩长、桩径、桩间距等,并通过m值反演和数理统计分析,得到如下主要结论： 1.无论是单桩还是群桩基础,桩身水平位移和桩身弯矩都随水平荷载的增大而增大；对于群桩基础,各排桩桩身水平位移随水平力的变化基本一致,前排桩最大弯矩大于中、后桩的最大弯矩,中、后排桩的最大弯矩基本相同。 2.无论是单桩还是群桩基础,桩身刚度对桩身水平位移、桩身弯矩和各排桩的桩身最大弯矩分担比例均影响较小。 3.无论是单桩还是群桩基础,桩径增大,桩身水平位移减小,同时桩身弯矩增大：对于群桩基础,增大桩径,中、后排桩的桩身最大弯矩分担比例有所提高。 4.无论是单桩还是群桩基础,桩长增大对桩身水平位移和桩身弯矩均影响很小；对于群桩基础,桩长增大,中、后排桩的桩身最大弯矩分担比例有所提高。 5.群桩基础中,纵向桩间距增大,桩身水平位移明显减小,同时桩身最大弯矩减小,且中、后排桩的桩身最大弯矩分担比例降低较多,平均降低了13%；横向桩间距增大,桩身水平位移减小,桩身最大弯矩增大,中、后排桩的桩身最大弯矩分担比例有所降低,分别降低了2%和9%。 6.群桩基础中,针对沪通高铁工程三个典型软土地层,中排桩桩身最大弯矩占前排桩桩身最大弯矩的比例为65%～74%；后排桩桩身最大弯矩占前排桩桩身最大弯矩的比例为55%-73%。 7.对m值进行反演分析和统计分析,得到该地区更精确的m值范围以及m与主要影响参数之间的关系式。
[Abstract]:Because the soft soil has the characteristics of low strength and high pressure shrinkage, the pile foundation is generally chosen in the soft soil area, but the bearing capacity of the pile foundation under the horizontal load is a very complicated process of pile soil interaction. At the same time, the m method in the standard is influenced by many factors, and the design of the lateral bearing pile foundation in the soft soil area can't be achieved. In this paper, the main factors affecting the horizontal bearing performance of single pile and pile foundation are analyzed with ABAQUS numerical analysis method, and the horizontal loading characteristics are compared, including pile length, pile diameter and pile spacing, and the m value inversion and mathematical statistics are used. The main conclusions are as follows:
1. both the single pile and the group pile foundation, the horizontal displacement and the pile bending moment of the pile increase with the increase of the horizontal load; for the group pile foundation, the horizontal displacement of each pile pile body is basically consistent with the horizontal force, the maximum bending moment of the front pile is greater than that in the middle, the maximum bending moment of the post pile, the maximum bending moment of the back row pile is basically the same.
2. whether it is single pile or group pile foundation, pile stiffness has little effect on the horizontal displacement of pile, the moment of pile and the maximum moment share of piles.
3. whether single pile or group pile foundation, pile diameter increases, pile body horizontal displacement decreases, and pile body bending moment increases. For group pile foundation, increasing pile diameter, and the maximum bending moment sharing ratio of pile body in back row pile increases.
4. no matter the single pile or the group pile foundation, the pile length increase has little influence on the horizontal displacement of the pile body and the pile body bending moment. For the group pile foundation, the pile length increases, and the maximum bending moment sharing ratio of the pile body in the back row pile increases.
In the 5. group pile foundation, the vertical pile spacing increases, the horizontal displacement of pile body decreases obviously, and the maximum bending moment of pile body decreases. In addition, the proportion of maximum bending moment of pile body in back row pile is reduced more, the average decrease of 13%, the horizontal displacement of pile body and the maximum bending moment of pile body increase, and the maximum bending moment of pile body is shared in the back row pile. The ratio is reduced by 2% and 9%., respectively.
In the 6. group pile foundation, according to the three typical soft soil strata of Hutong high speed rail project, the maximum bending moment of the middle row pile pile body is 65% ~ 74%, the maximum bending moment of the rear pile pile body is 55%-73%.
7. inverse analysis and statistical analysis of the m value, get the more accurate m range in this area and the relationship between M and main influence parameters.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.15

【参考文献】