Abstract: In order to explore the distribution of soil pressure on the side of the pile, bending moment of pile shaft and horizontal displacement of the pile top during the excavation and pile loading stages of the H-shaped prestressed concrete piles,three groups of indoor scaled model tests with prestressed rectangular piles and with or without prestressed H-shaped piles are carried out. And the test results show that the lateral earth pressure on both sides of the sheet pile has the same trend as the static earth pressure calculation value when it is not excavated, but the measured earth pressure at different depths is always lower than the static earth pressure calculation value. In the excavation stage,the lateral earth pressure on the excavation side of prestressed H-shaped piles is smaller than that of rectangular sheet piles and non-prestressed H-shaped piles. The ultimate bearing capacity of H-shaped piles under prestressed condition is about 1.33 times of that of rectangular sheet piles,taking the stacking weight at the critical displacement value as the bearing capacity index. The results show that the prestressed H-type piles have the optimal comprehensive performance, which can effectively improve the mechanical behavior of the pile shaft and significantly enhance the bearing capacity, thus possessing great engineering application value.

Key words: H-typed, prestress, model test, earth pressure, bending moment of pile shaft

摘要： 为探究H型预应力混凝土桩在开挖和堆载阶段的桩侧土压力分布、桩身弯矩和桩顶水平位移,进行预应力矩形桩和H型桩、无预应力H型桩3组室内缩尺模型试验。试验结果表明:未开挖时,板桩两侧侧向土压力与静止土压力理论计算值的趋势相同,但实测土压力小于静止土压力计算值;在开挖阶段,施加预应力H型桩开挖侧的侧向土压力小于矩形板桩和无预应力H型桩;以达到临界位移值时的堆载重量作为承载力指标,加预应力工况下H型桩的极限承载力约为矩形板桩的1.33倍。结果显示,预应力H型桩综合性能最优,能有效改善桩身受力并显著提高承载能力,工程应用价值较大。

关键词: H型, 预应力, 模型试验, 土压力, 桩身弯矩