Monitoring of internal force characteristics of uplift piles of excavated foundation pit in soft soils
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摘要: 软土地区地下抗浮设计通常采用设置抗拔桩法,但由于场地条件的复杂性,施工完成后抗拔桩内力的发挥情况及坑底孔隙水压力不够明了。采用普通钢筋计和光纤光栅钢筋计对宁波轨道交通1号线福明路站抗拔桩长期内力和底板下孔隙水压力进行监测。结果表明：由于光纤光栅钢筋计可剔除温度应力的影响,应用于抗拔桩内力测试比较合理；抗拔桩内力先表现为拉力,后期表现为压力,说明在前期抗拔桩能发挥其抗拔作用,后期则作为抗压桩来抵抗上部结构的压力作用；坑底孔隙水压力随时间的增加呈增大趋势,但增速较缓,水土压力比较稳定。Abstract: Uplift piles are usually used in the anti-floating design of underground engineering in soft soil areas, but due to the complexity of the site conditions, the play of internal force after construction and the recovery of pore-water pressure are not yet clear. Therefore, the common reinforced meter and fibre grating reinforced meter are used to monitor the long-term internal forces of uplift piles at Fuming Road station, line 1 of Ningbo rail transit traffic, and the tests on the pore-water pressure are also performed. The measured results indicate that the fibre grating reinforced meter is reasonable for monitoring the internal forces of anti-pulled piles because it can remove the produced prestressed effect of temperature changes. The internal force in uplift piles performs as pulling force firstly, then displays as pressure later, and the uplift piles play its anti-pulled role in early, and later as a superstructure of compressive pile to resist pressure. In addition, the pore-water pressure increases with time at the end of the hole, but the rate of growth is slow, and the soil water pressure under all conditions is steady.
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Keywords:
- excavation /
- uplift pile /
- internal force /
- monitoring
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