论文部分内容阅读
PHC(prestressed high-strength concrete)管桩近年来被广泛应用。PHC管桩为挤土沉桩模式,沉桩过程引起的挤土效应对周围环境产生不利影响并对其可打性和承载特性有重要影响。结合广-清(广州至清远)高速公路扩建工程,通过现场监测超静孔隙水压力和土体水平位移,进行PHC管桩挤土效应研究。水平位移利用固定式测斜仪测量,孔隙水压力使用振弦式孔压计测量,并使用自动系统进行数据采集。研究发现,沉桩过程中引起的超静孔隙水压力变化随深度增加近似呈线性增长,水平方向随距离的增加而减小;挤土效应产生的土体水平位移随距离的增大而减小,随深度增加而减小;挤土效应滞后现象明显,可导致成桩后的桩体倾斜;拓宽地基场地上管桩施工对老路地基影响小,场地条件对沉桩挤土效应影响大,老路路堤对垂直于路基方向的水平位移有约束作用。
PHC (prestressed high-strength concrete) pipe pile is widely used in recent years. The PHC pipe pile is a mode of soil compaction and pile sinking. The soil compaction effect caused by pile driving has an adverse effect on the surrounding environment and has an important influence on its accessibility and bearing characteristics. Combined with Guang-Qing (Guangzhou to Qingyuan) expressway expansion project, through the on-site monitoring of excess pore water pressure and horizontal displacement of soil, PHC pipe pile crowding effect. Horizontal displacement was measured using a stationary inclinometer, pore water pressure was measured using a vibrating wire piezometer, and data was collected using an automated system. It is found that the change of excess pore water pressure caused by pile sinking increases linearly with the increase of depth and the horizontal direction decreases with the increase of distance. The horizontal displacement of soil mass produced by squeezing effect decreases with the increase of distance , Which decreases with the increase of depth. The hysteresis of squeezing effect is obvious, which can lead to the tilting of piles after piling. The widening of the foundation pile on the foundation has little influence on the groundwork of the old road, and the site conditions have a great influence on the effect of pile- The embankment has a constraining effect on the horizontal displacement perpendicular to the embankment.