沉井基础竖向承载特性的离心模型试验研究  

Centrifugal Model Test on Vertical Bearing Properties of Open Caisson Foundation

作　　者：胡中波[1] 马建林[1] 徐力[2] 梅新咏[2] 王钦科 HU Zhong-bo MA Jian-lin XU Li MEI Xin-yong WANG Qin-ke(Southw est Jiaotong U niversity, C hengdu 6 1 0 0 3 1 ,C h in a C hina Railw ay M ajor BridgeR econnaissance ＆ D esign Group Co. ,L td ., W uhan 4 3 0 0 5 6 ,C h in a)

机构地区：[1]西南交通大学,成都610031 [2]中铁大桥勘测设计院集团有限公司,武汉430056

出　　处：《铁道标准设计》2016年第12期80-84,共5页Railway Standard Design

基　　金：中国铁路总公司科技研究开发计划(2013G001-A-2)

摘　　要：基于离心模型试验对饱和砂土地基中沉井基础在竖向荷载作用下的承载特性进行研究,初步掌握地基极限承载力随基础埋深和基础宽度变化的规律,并对试验结果进行对比分析,结果表明:(1)基础埋深不大于5 m时,荷载-沉降曲线为陡降型,有明显的拐点出现,可取拐点对应的荷载作为极限承载力;基础埋深不小于10 m时,荷载-沉降曲线为缓变型,未出现明显的拐点,建议取相对沉降量(基础的实测沉降量与基础宽度的比值)对应的荷载作为极限承载力。(2)在均质地基环境中,极限承载力随基础相对埋深的增加近似呈指数型曲线增长。(3)进一步推求沉井基础极限承载力随基础宽度和相对埋深变化的函数表达式,其成果可用于估算砂土地基中沉井基础的地基极限承载力。Based on centrifuge model test,the bearing properties of open caisson foundation in saturatedsand under vertical load are studied, the variation law of the ultimate bearing capacity of soil with thechange of the embedded depth and foundation are identified,and contrastive analysis of the test resultsare conducted. The results show that （1） when the embedded depth of foundation is less than 5 meters,the curve shape of load-settlement is steep and there is a clear inflection point and the desirable inflectionpoint corresponding to the load is the ultimate bearing capacity; when the embedded depth of foundationis not less than 10 meters,the curve shape of load-settlement is flat and no clear inflection point showedin the curve,and it is suggested the loading with relative settlement S/B = 0. 07 ？0. 08 be regarded asthe ultimate bearing capacity; （2） in homogeneous foundation, the ultimate bearing capacity increasesexponentially with the increase of the relative embedded depth of foundation; （3） the expression functionon the ultimate bearing capacity of open caisson foundation is further derived in view of the influence ofthe relative depth and foundation width,which can be used to estimate the ultimate bearing capacity ofthe open caisson foundation in sand soil.

关 键 词：沉井基础 离心模型试验 极限承载力 基础埋深 基础宽度 

分 类 号：TU473.2[建筑科学—结构工程]