滨海相软土地基沉井承载性能试验研究  

Field Experimental Study on Bearing Capacity of Open Caisson in Coastal Soft Soil

作　　者：祁昊 张金龙 崔强 吴昊 程澍 曹巍 QI Hao;ZHANG Jinlong;CUI Qiang;WU Hao;CHEN Shu;CAO Wei(States Grid Lianyungang Power Supply Company,Lianyungang 222000,China;China Electric Power Research Institute,Beijing102401,China)

机构地区：[1]国网连云港供电公司,江苏连云港222000 [2]中国电力科学研究院有限公司,北京102401

出　　处：《三峡大学学报（自然科学版）》2023年第1期67-73,共7页Journal of China Three Gorges University：Natural Sciences

基　　金：国网江苏省电力公司科技项目(J2020036)。

摘　　要：以连云港地区滨海相软土地基中的复合沉井基础为研究对象,分别开展了上拔、下压、水平3种荷载工况下的真型基础现场承载性能试验,对比分析了不同荷载工况下复合式沉井基础的荷载位移曲线、极限承载力及影响因素、地基破坏模式.结果表明:3种荷载工况下复合式沉井基础的荷载位移曲线整体呈“直线-曲线-直线”的缓变型特征,由于沉井侧面及基底以下原状土体固结作用的影响,水平、下压荷载工况下试验基础的弹塑性变形性状较上拔荷载工况更为明显;3种荷载工况下复合式沉井基础的极限承载力由大到小依次为下压、上拔、水平;由于下部沉井的影响,复合式沉井基础柱侧及基底处的土体压力进行了重新分配,更加符合水平荷载作用下刚性短桩的受力模式;上拔荷载作用下的复合式沉井基础,其周围土体经历了“土体受拉破坏-局部剪切破坏-整体剪切破坏”的破坏过程,破坏面形状可等效为自底板上表面起裂,以57°的上拔角一直延伸至地表面的倒锥体.In this paper,the composite open caisson foundation for transmission line in coastal soft soil located in Lianyungang area is taken as the research object,and the field test of bearing capacity of foundation under uplift load,vertical load and horizontal load are carried out respectively.The load-displacement curve,ultimate bearing capacity and soil failure mode of the tested foundation under different load cases are compared and analyzed.The results show that the load-displacement curves of the composite open caisson foundation under the three load cases are of“straight line-curve-straight line”and the elastic-plastic deformation behavior of the test foundation under horizontal and vertical downward load cases is more obvious than that under uplift load cases due to the influence of the consolidation of undisturbed soil at the side of the open caisson and below the foundation base.The ultimate bearing capacity of the composite open caisson foundation under the three load cases is vertical load,uplift load and horizontal load respectively.Due to the influence of the lower open caisson,the soil pressure at the column side and base of the composite open caisson foundation is redistributed,which better conforms to the stress mode of the rigid short pile under the horizontal load.For the composite open caisson foundation under uplift load,the surrounding soil has undergone a failure process of“soil tensile failure-local shear failure-overall shear failure”,and the shape of the failure surface can be equivalent to an inverted cone that cracks from the upper surface of the bottom plate and extends to the ground surface with an uplift angle of 57°.

关 键 词：滨海相软土 复合沉井基础 输电线路 现场试验 承载特性 

分 类 号：TU43[建筑科学—岩土工程]