Wang Yonghong, Liu Xueying, Zhang Mingyi, Yang Suchun, Sang Songkui
College of Civil Engineering, Qingdao University of Technology, Qingdao 266033, China.
Collaborative Innovation Center of Engineering Construction and Safety in Shandong Blue Economic Zone, Qingdao University of Technology, Qingdao 266033, China.
Sensors (Basel). 2020 May 16;20(10):2829. doi: 10.3390/s20102829.
Prestressed high-strength concrete (PHC) pipe pile with the static press-in method has been widely used in recent years. The generation and dissipation of excess pore water pressure at the pile-soil interface during pile jacking have an important influence on the pile's mechanical characteristics and bearing capacity. In addition, this can cause uncontrolled concrete damage. Monitoring the change in excess pore water pressure at the pile-soil interface during pile jacking is a plan that many researchers hope to implement. In this paper, field tests of two full-footjacked piles were carried out in a viscous soil foundation, the laws of generation and dissipation of excess pore water pressure at the pile-soil interface during pile jacking were monitored in real time, and the laws of variation in excess pore water pressure at the pile-soil interface with the burial depth and time were analyzed. As can be seen from the test results, the excess pore water pressure at the pile-soil interface increased to the peak and then began to decline, but the excess pore water pressure after the decline was still relatively large. Test pile S1 decreased from 201.4 to 86.3 kPa, while test pile S2 decreased from 374.1 to 114.3 kPa after pile jacking. The excess pore water pressure at the pile-soil interface rose first at the initial stage of consolidation and dissipated only after the hydraulic gradient between the pile-soil interface and the soil surrounding the pile disappeared. The dissipation degree of excess pore water pressure reached about 75-85%. The excess pore water pressure at the pile-soil interface increased with the increase in buried depth and finally tended to stabilize.
近年来，静压法预应力高强混凝土（PHC）管桩得到了广泛应用。沉桩过程中桩土界面超孔隙水压力的产生与消散对桩的力学特性和承载能力有重要影响。此外，这还可能导致混凝土出现不可控损伤。监测沉桩过程中桩土界面超孔隙水压力的变化是许多研究人员希望实施的一项计划。本文在黏性土地基中进行了两根全桩长静压桩的现场试验，实时监测了沉桩过程中桩土界面超孔隙水压力的产生与消散规律，并分析了桩土界面超孔隙水压力随埋深和时间的变化规律。从试验结果可以看出，桩土界面超孔隙水压力先升高至峰值然后开始下降，但下降后的超孔隙水压力仍相对较大。沉桩后，试验桩S1从201.4 kPa降至86.3 kPa，试验桩S2从374.1 kPa降至114.3 kPa。桩土界面超孔隙水压力在固结初期先上升，仅在桩土界面与桩周土体之间的水力梯度消失后才消散。超孔隙水压力的消散程度达到了75% - 85%左右。桩土界面超孔隙水压力随埋深增加而增大，最终趋于稳定。
