塑料套管混凝土桩的承载力时间效应研究

Time effect of bearing capacity of plastic tube cast-in-place concrete piles

在塑料套管混凝土桩（TC桩）成桩机理的基础上,采用圆柱扩孔回缩理论和径向固结理论预测TC桩施工引起的桩周土超净孔压的消散,建立了TC桩承载时效的理论计算方法。通过开展现场试验,对比研究了TC桩承载时效理论的合理性。结果表明：考虑桩周土的回缩的承载时效计算结果及其随时间变化的规律与实测值相吻合;而不考虑回缩时,不同休止期对应的承载力将被高估160%~300%。

Based on the installation mechanism of plastic tube cast-in-place concrete piles （TC pile）, the method for time effect of bearing capacity of TC pile was established by employing both of the theories of cylindrical cavity expansion and contraction and radial consolidation. According to the field tests, the rationality of the time-effect theory for TC pile was comparatively studied. The results show that the calculated values of bearing capacities with time by considering the contraction of soils surrounding the TC pile shaft are consistent with the measured ones. However, the calculated values in different rest periods will be overestimated by 160%~300% compared with the measured ones as the contraction of soils is ignored.