黄土冲沟斜坡桥梁桩基竖向承载特性模型试验研究

为了探明黄土冲沟地形条件对桥梁桩基础承载力的影响,首次基于自主研发的能充分反映黄土冲沟区域桩基础特点与工作性能的模型试验平台,分析不同冲沟坡度、不同桩长桩基的竖向承载力,桩身轴力及桩侧摩阻力的变化规律,并结合试验结果提出相关的工程技术建议。研究结果表明:1随着坡度的增大,相同桩长的桩基承载力呈降低趋势,承载力影响度逐渐增大,变化范围在7%~35%之间;2在一定范围内,桩基承载力随桩长增加增幅越大,桩长增加到一定程度时,承载力增幅逐渐变缓;3随着坡度增加,相同入土深度下的有效桩长逐渐减小;4黄土冲沟斜坡区域桥梁桩基设计应充分考虑防止桩周土体流失的工程技术。

Model tests on vertical bearing performance of bridge pile foundation in loess gulch slope area

In order to ascertain the effect of loess gulch on the bearing capacity of bridge pile foundation, for the first time, based on the self-developed platform model test, the model tests can fully reflect the characteristics and work performance of pile foundation in loess gulch area. The change rules of vertical bearing capacity, pile axial force and lateral friction force of the pile foundation with different slopes and pile lengths are analyzed, and some engineering technical advices are given based on test results. The results show that: (1) With the increase of slope, the bearing capacity of piles with the same pile length decreases, the influence degree of bearing capacity increases gradually, and the range varies from 7% to 35%. (2) The pile bearing capacity increases with the increase of pile length to some extent; when the pile length increases to a certain length, the rate of increase becomes slow. (3) The effective pile length with the same buried depth decreases with the increase of slope. (4) The design of bridge pile foundation should fully consider the engineering technology of preventing the soil around piles being eroded in the loess gulch area.