先张法预应力抗拔桩截桩时桩顶处理分析

Analysis on pile head treatment of pre-tension-pre-stressed uplift pile when cutting pile

先张法预应力桩由于桩身的有效预压应力,耐久性较好。工作状态时桩顶受拉荷载最大,若需要截桩,桩顶一定长度范围内有效预压应力不足,如何保证桩顶承载力及耐久性尤为重要。目前可选用的大部分先张法预应力抗拔桩图集中,未提供抗拔桩截桩节点大样或大样中的处理方法不全面。结合预应力抗拔桩桩顶截桩后的耐久性验算实例,提出预应力抗拔桩截桩后不能满足耐久性要求时,应在桩顶一定长度内采取加强措施。

Pre-tension-pre-stressed piles have better durability due to the effective pre-compressive stress of the pile body.The tensile load on the top of pile is the largest under working condition.If cutting pile is needed,effective precompressive stress within a certain length range of pile top is insufficient,and how to ensure the bearing capacity and durability of the pile top is particularly important.In most of the currently available pre-tension-stressed uplift pile maps,large samples of the uplift pile are not provided or the processing methods in the large samples are not comprehensive.Based on the example of durability check calculation of the pre-tension-stressed uplift pile which top is cut off,it is proposed that strengthening measures should be taken within a certain length of the pile top,when pre-tension-stressed uplift pile can not meet the durability requirements after the pile top is cut off.