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采用泥浆护壁的钻孔灌注桩,在施工过程中,由于泥浆循环时间的不同,会在桩身表面形成一层不同厚度的泥皮,导致桩侧阻力降低,影响单桩的承载特性。通过对4根泥浆循环时间不同的钻孔灌注桩进行室内模型试验,对比分析了砂土中泥浆循环时间对模型桩受力性状的影响。试验结果表明:在相同条件下,泥浆循环时间的增加会导致桩顶沉降的增大,模型桩S2,S3和S4的桩顶沉降分别较S1增加了14.0%,26.2%和53.8%;泥浆循环时间的长短,会对桩身轴力的分布造成一定影响,且随着泥浆循环时间的增加,桩身轴力递减幅度变小,桩端阻力逐渐增大,总的桩侧阻力逐渐降低,但不同埋深段的桩侧阻力变化规律有所差异;在相同的桩土相对位移下,各模型桩不同埋深段的桩侧阻力随埋深的增加而增大;随着泥浆循环时间的增加,桩侧阻力完全发挥所需的极限桩土相对位移量逐渐增大。
In the process of construction, bored piles with slurry retaining walls form a layer of mud with different thicknesses on the surface of the pile due to the different mud circulation time, which leads to the decrease of the resistance on the pile side and the bearing capacity of single pile. Through the indoor model test of four bored piles with different mud circulation times, the influence of the mud circulation time on the behavior of the model pile is analyzed. The experimental results show that under the same conditions, the increase of mud circulation time will lead to the increase of pile top settlement, and the pile top settlement of model piles S2, S3 and S4 increases by 14.0%, 26.2% and 53.8% respectively compared with S1; The length of time will affect the axial force distribution of the pile. With the increase of the mud circulation time, the decrease of the axial force of the pile becomes smaller and the resistance of the pile end gradually increases, while the resistance of the pile side gradually decreases. The variation of pile-side resistance in different depth sections is different. With the same relative displacement of pile-soil, the pile-side resistance at different depths increases with the increase of buried depth. With the increase of mud circulation time , The relative displacement of the limit pile and soil needed for full pile side resistance to fully develop gradually increases.