作　　者： (朱小军）; (孔伟阳）; (李文帅）;

机构地区： 东南大学土木工程学院,南京市210096 扬州大学建筑科学与工程学院,扬州市225127

出　　处： 《公路》 2017年第8期1-7,共7页

摘　　要： 为了研究高置换率挤密砂桩复合地基加固体系的沉降、破坏机理及承载特性,通过自行研发的可视化模型试验装置,进行了单桩、普通置换率与高置换率挤密砂桩复合地基对比模型试验,获得了高置换率挤密砂桩复合地基的荷载-沉降、桩土应力比、沉降-时间及桩土应力比-时间数据。试验结果分析表明:砂桩单桩与群桩复合地基相比,其承载力低,沉降量大;当置换率达到55%以上时,砂桩复合地基承载力提高幅度较大,沉降及桩土应力比随时间效应显著,表明高置换率下砂桩置换作用较明显,可以充分发挥桩间土的承载特性。根据挤密砂桩的承载特性及国内外相关资料,总结了挤密砂桩承载力的计算方法,并采用70%高置换率挤密砂桩室内模型试验进行验证,对比承载力的各种计算方法,为实际工程设计应用提供参考。 To study the settlement, failure mode mechanism and bearing characteristic of compositefoundation with high replacement ratio sand compacted piles, single and regular replacement ratio sand piles composite foundations contrast model tests on composite foundation with high replacement ratio sand compacted piles are conducted by means of laboratory visualization model testing devices. The data about the load-settlement, pile-soil stress ratio, settlement-time and pile-soil stress ratio-time of composite foundation with high replacement ratio sand compacted piles are obtained. The results show that compared with group pile composition foundation, the bearing capacity of the single sand pile is lower, and the settlement is larger~ when the replacement ratio is above 55%, the increase of bearing capacity about sand pile composite foundation is more larger, significant time effect of settlement and pile-soil stress ratio, obvious sand pile replacement under high replacement ratio and full improvement of the bearing capacity of the soils between piles. According to the bearing characteristics of sand compaction piles and related data at home and abroad, the calculation method about the bearing capacity of sand compaction pile is summarized, and the model test of 70% high replacement ratio sand compaction piles is verified, various calculation methods of bearing capacity are compared which can provide preliminary design reference for practical engineering projects.

关 键 词： 高置换率 挤密砂桩 复合地基 模型试验 承载力