路堤荷载下塑料套管桩荷载传递机制的现场试验研究

用于公路软基处理的塑料套管桩是由预先打设在地基中的塑料套管内浇注混凝土组成的。通过在塑料套管桩身埋设钢筋应力计，完整测试了路堤填筑荷载过程及预压期内路堤荷载作用下塑料套管桩的荷载传递机制，同时提出了钢筋应力计的修正方法。试验结果表明：单桩静载下塑料套管桩身轴力沿深度逐渐减小且无负摩阻力；在路堤荷载作用下塑料套管桩桩身轴力沿深度先增大后减小，负摩阻力分布在桩长上部3/5范围内，且随着填土荷载的增加，负摩阻力和正摩阻力都逐步增加，但在监测期内负摩擦力中性点位置保持不变。

Field test study of load transfer mechanism of plastic tube pile under embankment loading

The plastic tube pile applied to soft ground treatment of highway, is comprised of pre-driven plastic tube filled with concrete. According to the steel stress gauges embedded in plastic tube pile, the load transfer mechanism of plastic tube pile under embankment load is completely measured during the periods of construction and precompression. And the modified method of steel stress gauge is proposed. The test results show that under the static load of single pile, the axial load of plastic tube pile decreases with the depth increasing, and there is no negative skin friction; under the embankment load, the axial load of plastic tube pile increases first and then decreases, and the distribution of negative skin friction is in the upper 3/5 of pile length; with the increasing of embankment load, the negative and positive skin frictions are gradually increased; however, the location of neutral point of negative skin friction stay the same during the observation period.