塑料套管混凝土桩加固公路软土地基现场试验研究

根据某一高速公路塑料套管混凝土桩加固软土地基工程实例，对桩土应力、地表沉降、横向位移、不同深度孔隙水压力进行观测，讨论了塑料套管混凝土桩桩承式路堤的工作机理。结果表明：塑料套管桩加筋路堤的临界高度约为1.26倍桩净距，观测期末，荷载分担比接近89%；桩帽和桩间土最大差异沉降为30 mm左右，且应力集中比随着差异沉降的增大而线性增大；路堤堤脚附近不同深处横向位移随着路堤填筑高度的增加而增加，施工结束时，地表以下2.5 m处横向位移最大，为12.86 mm；横向位移-沉降比和横向位移增加率随着路堤填筑高度的增加逐步减小并趋于稳定，塑料套管混凝土桩加筋路堤系统能够有效防止路堤横向位移的发展和改善路堤的整体稳定性。

Field tests on plastic tube cast-in-place concrete piles for reinforcing soft ground of highways

Based on a case of plastic tube cast-in-place concrete piles for reinforcing soft ground of a highway, the characteristics of the plastic tube cast-in-place concrete pile supported embankment system are studied by measuring the pile-soil stress, surface settlement, horizontal displacement, and pore water pressure at different depths. The test results show that the critical height of the plastic tube cast-in-place pile-supported embankment is about 1.26 times the net pile space. The load-sharing ratio approaches 89% at the end of monitoring. The settlements of piles and soils and the differential settlements between piles and soils mainly occur during the period of embankment construction. The measured maximum differential settlement between piles and soils is about 30 mm; and the stress concentration ratio linearly increases with the differential settlement between piles and soil. The lateral displacements at different depths near the embankment toe increase with the increasing embankment height. The maximum lateral displacement is 12.86 mm and located 2.5 m in depth under the surface at the end of embankment construction. The lateral displacement-settlement ratio and the increment ratio of lateral displacement are reduced and stabilized with the increase of the embankment height, which indicates that the plastic tube cast-in-place concrete pile-supported embankment system can prevent the development of lateral displacement and improve the whole stability of embankment effectively.