高速铁路大直径桩基础水平承载力机理研究

结合连镇铁路新沂河特大桥试桩工程,通过单向多循环加载法对桩端自由的PHC管桩和钻孔灌注桩进行水平承载力试验得出地基土水平抗力系数的比例系数m值;采用有限元软件对钻孔灌注桩进行数值模拟得出沿桩长范围的剪力、弯矩、位移和桩侧土抗力分布曲线。研究表明,同类地质条件下,两种桩基础工程特性不同,实际工程中可结合具体工程要求合理选择桩基础结构形式;钻孔灌注桩弯矩最大值主要分布在自桩顶1/4桩长范围内,桩身水平位移和桩侧土抗力最大值主要分布在自桩顶桩长1/8和自桩底部1/4桩长范围内。

Study on the Horizontal Bearing Capacity Mechanism of Large-diameter Pile Foundation of High-speed Railway

Combined with the trial pile project of Xinyi River Bridge on Lianzhen Railway,this study is launched.The horizontal load-bearing capacity test of PHC pipe piles and bored piles with free ends by the unidirectional multi-cycle loading method obtains the proportional coefficient of the horizontal resistance coefficient of the foundation soil,that is,the m value;through the use of finite element software to simulate the bored pile,the distribution curves of shear force,bending moment,displacement and pile side soil resistance along the pile length are obtained.The research shows that under the same geological conditions,the engineering characteristics of the two types of pile foundations are different,and the structure of the pile foundation can be reasonably selected according to the specific engineering requirements in the actual project;the maximum bending moment of bored piles is mainly distributed within the 1/4 pile length from the top of the pile.The maximum values of the horizontal displacement of the pile and the soil resistance of the pile side are mainly distributed in the range of 1/8 of the pile length from the top of the pile and 1/4 of the pile length from the bottom of the pile.