长短桩复合地基的受力特性及其影响因素分析  

Analysis on the Stress Characteristics and Influencing Factors of Long-Short Pile Composite Foundation

作　　者：张义伟 ZHANG Yiwei(Suizhou Urban Planning Survey and Design Research Institute,Suizhou 441300,Hubei,China)

机构地区：[1]随州市城市规划勘测设计研究院,湖北随州441300

出　　处：《工程技术研究》2023年第22期20-23,共4页Engineering and Technological Research

摘　　要：针对在实际工程中单一短桩或长桩无法满足工程需求的问题,文章通过将短桩和长桩相组合,提出了长短桩复合地基。其中,柔性短桩能够优化浅层软土特性,刚性长桩可以减小土体沉降,褥垫层能够合理分配桩间土和桩体间的荷载。文章以随州市文化公园片区公园三号小区项目为依托,通过建立数值模型,分析了桩间距、桩长、褥垫层厚度等因素对复合地基受力情况的影响,研究结果表明:桩间土应力会随褥垫层刚度和桩身长度的增加而逐渐降低,但持续增大褥垫层刚度并不能大幅度减小桩间土的应力;桩间土应力随着桩间距与褥垫层厚度的增大而增大,但较大的桩间距会导致桩间土受力面积比例增大,作用在桩体上的荷载比例减小,不利于控制地基沉降。通过综合考虑场区地质情况、工程特点和工程成本后,确定褥垫层刚度为40 MPa,厚0.4 m,桩间距为4倍桩径,桩长18 m。文章研究成果可为类似地基处理工程提供借鉴和参考。In view of the problem that a single short pile or long pile can not meet the engineering requirements in practical engineering,this paper proposes a long-short pile composite foundation by combining short piles and long piles.Among them,the flexible short pile can optimize the characteristics of shallow soft soil,the rigid long pile can reduce the settlement of soil,and the cushion layer can reasonably distribute the load between piles and soil.Based on the project of Park No.3 Community in Suizhou Cultural Park area,this paper analyzes the influence of factors such as pile spacing,pile length,cushion layer thickness on the stress of composite foundation by establishing a numerical model.The results show that the stress of soil between piles gradually decreases with the increase of cushion layer stiffness and pile length,but the continuous increase of cushion layer stiffness can not greatly reduce the stress of soil between piles;the soil stress between piles increases with the increase of pile spacing and cushion layer thickness,but the larger pile spacing will lead to the increase of the stress area ratio of the soil between piles,and the decrease of the load ratio on the pile,which is not conducive to the control of foundation settlement.By comprehensively considering the geological conditions,engineering characteristics and engineering costs of the site,the cushion layer stiffness is determined to be 40 MPa,the thickness is 0.4 m,the pile spacing is 4 times as long as the pile diameter,and the pile length is 18 m.The research results of this paper can provide reference for similar foundation treatment engineering.

关 键 词：长短复合桩基础 柔性短桩 刚性长桩 桩间土应力 

分 类 号：TU473.1[建筑科学—结构工程]