高速公路改扩建旧桥加宽桩基础差异沉降控制离心模型试验  

Centrifugal model test on differential settlement control of widened pile foundation of old bridge in reconstruction and extension of expressway

作　　者：冯忠居[1] 陈锦华 刘星越 王富春[1] 徐浩 FENG Zhong-ju;CHEN Jin-hua;LIU Xing-yue;WANG Fu-chun;XU Hao(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064

出　　处：《长安大学学报（自然科学版）》2022年第2期1-9,共9页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51708040);中央高校基本科研业务费专项资金项目(300102218115)。

摘　　要：为解决高速公路改扩建工程旧桥加宽中新旧桩基的差异沉降问题,依托北河崖大桥加宽工程,通过室内离心模型试验,分别研究了新桩不同桩长、不同桩径下单桩承载特性和新旧桩基差异沉降变化规律,并结合敏感性分析方法,得出北河崖大桥新桩桩长、桩径合理增量范围,提出了高速公路改扩建旧桥加宽桩基础差异沉降控制技术参数。结果表明:新桥桩基施工会明显降低旧桩承载力;新桩沉降量比旧桩沉降量高15.4%,新旧桩共同作用时,旧桩沉降量比单桩沉降量高11.2%;当新桩桩长增加3、5、7、10 m时,差异沉降减幅分别为24.5%、37.4%、45.7%、53.8%;当新桩桩径增大0.3、0.5、0.7、1.0 m时,差异沉降减幅分别为24.7%、36.3%、44.1%、50.4%,但当桩长、桩径继续增大后,差异沉降控制效果将趋于稳定;新桩桩长、桩径合理增量范围分别为3~7 m和0.3~0.7 m;新桩采用桩长15 m、桩径1.8 m或桩长18 m、桩径1.5 m方案,可较好控制新旧桩基差异沉降,研究方法和结果可为类似工程提供参考。In order to solve the problem of differential settlement of new and old pile foundation in the widening project of old bridge of expressway reconstruction and expansion project,relying on the widening project of Beiheya Bridge,through indoor centrifugal model test,the bearing characteristics of new piles with different pile lengths,diameters,and the variation law of differential settlement between new and old piles were studied respectively,and then combined with the sensitivity analysis method,the reasonable increment range of new pile length and pile diameter of Beiheya Bridge was obtained.The differential settlement control technology of widening pile foundation of old bridge in expressway reconstruction and expansion was put forward.The results show that the pile foundation construction of the new bridge will obviously reduce the bearing capacity of the old pile,the settlement of the new pile was 15.4% higher than that of the old pile,and the settlement of the old pile was 11.2% higher than that of the single pile when the length of the new pile increases by 3,5,7 and 10 m,the differential settlement decreases by 24.5%,37.4%,45.7% and 53.8%,respectively.When the diameter of new pile increases by 0.3,0.5,0.7 and 1.0 m,the differential settlement decreases by 24.7%,36.3%,44.1% and 50.4%,respectively,but when the pile length and pile diameter continue to increase,the control effect of differential settlement will tend to be stable.The reasonable increment range of the length and diameter of the new pile is 3 to 7 m and 0.3 to 0.7 m,respectively.The new pile adopts the scheme of pile length 15 m,pile diameter 1.8 m or pile length 18 m and pile diameter 1.5 m,which can better control the differential settlement of new and old pile foundations.The research methods and results can provide reference for similar projects.5 tabs,11 figs,35 refs.

关 键 词：道路工程 差异沉降 离心模型试验 旧桥加宽 敏感性分析 控制参数 

分 类 号：U418.8[交通运输工程—道路与铁道工程]