大直径超长灌注桩侧阻力深度效应研究  

Study on depth effect of lateral friction for large-diameter and super-long bored piles

作　　者：张慧海 石怀清 张浩[3] 万再新 王东红 Zhang Huihai;Shi Huaiqing;Zhang Hao;Wan Zaixin;Wang Donghong(China JK Institute of Engineering Investigation and Design Co.,Ltd.,Xi＇ an 710043,China;Shaanxi Key Laboratory of Engineering Behavior and Foundation Treatment for Special Soil,Xi＇ an 710043,China;Northwest University,Xi＇ an 710069,China)

机构地区：[1]机械工业勘察设计研究院有限公司,西安710043 [2]陕西省特殊岩土性质与处理重点实验室,西安710043 [3]西北大学,西安710069

出　　处：《工程勘察》2018年第8期9-13,73,共6页Geotechnical Investigation & Surveying

基　　金：陕西省科技统筹创新工程计划(S2016TNSF0056)

摘　　要：为了研究黄土地区低阶地地基中超长灌注桩的承载性能、桩侧阻力分布规律及影响因素,对西安地区3根大直径超长灌注桩进行了单桩竖向承载力载荷试验,采用滑动测微计测试了桩身内力变化。试验结果显示:桩周以砂土为主的大直径超长灌注桩的Q-s曲线呈缓变型,单桩竖向抗压承载力大幅度高于规范经验参数法计算结果,大部分桩侧范围内的桩侧阻力均大于规范给出的经验标准值;存在临界桩土相对位移,在其两侧区间随着桩土相对位移的增加桩侧阻力表现出不同的变化规律;桩深对桩侧阻力影响明显,在同一地层中桩侧阻力随桩深的增加而增大,但增速逐渐降低,两者相关性较强。In order to study the bearing capacity behavior,the distribution of lateral friction and the affecting factors for the large-diameter and super-long bored piles at low terrace in loess,the vertical static loading tests are adopted for three piles in Xi＇an area,in which the variation of axis forces in piles is tested by using sliding micrometers.The test results show that the Q-s curves of the bored piles in sand soil are slowly varying,the real vertical compressive bearing capacity are far larger than the standard values from the specification experience parameter method,and the lateral friction of the most of the bored piles are larger than the standard values from the specification.There is a critical relative displacement of soilbored piles on the both sides where the change rule of lateral friction is different.In the same formation the lateral friction will increase with the increasing of the pile depth,but the increasing rate is reduced.

关 键 词：大直径超长灌注桩 单桩抗压承载力 桩侧阻力 相对位移 桩深 

分 类 号：TU413[建筑科学—岩土工程]