【摘要】 为了更好地研究一种新的施工工艺下微型桩的承载性状,选用两根微型桩做现场静载试验,每根桩中12个振弦式钢筋应力计被均匀布置于微型桩中.通过静载试验的结果发现,微型桩在承受抗压及抗拔时最终呈刺入破坏或桩身被拔出.土层性状和桩土相对位移对微型桩侧阻的发挥有很大关系,桩身侧阻随桩土相对位移变化呈应变硬化关系.不同土层及同一土层受力状态不同时,桩的临界侧阻和临界位移各不相同.通过将微型桩实测单位侧阻与静力触探试验结果对比分析发现,抗压时实测单位侧阻为静力触探试验的锥尖侧阻平均值的0.57~0.99倍,抗拔时实测单位侧阻为静力触探试验的锥尖侧阻平均值的0.37~0.72倍.抗压桩实测单位锥尖端阻为静力触探试验结果的0.38倍.更多还原

【Abstract】 In order to give a better insight into the behavior of a new type of micropile under compression and tension load,a load test program comprising two micropiles was conducted. Each pile was instrumented with 12 vibratingwire strain gauges. The results show that failure occurs in plugging and pull-out manners under compression and tension conditions,respectively. The soil properties and pile-soil relative displacement have great influence on the mobilization of shaft resistance. The relationship between shaft resistance and pile-soil relative displacement resembles the strain hardening model. Meanwhile,the critical displacement and the corresponding shaft resistance vary with soil profile and local stress state. Through a comparison with the average CPT sleeve friction,the measured shaft resistance is found to be 0.57—0.99 times the average CPT sleeve friction in compression and 0.37—0.72 times in tension,and the measured toe resistance is 0.38 times the average of CPT toe resistance.更多还原