广州地铁盾构下穿对近接高架桥桩基的影响分析

运用MIDAS/GTS三维有限元分析软件,模拟了盾构隧道动态施工对近接高架桥桩基的影响,重点分析了桩基水平位移及沉降的发展规律,为盾构安全通过提供依据。研究表明:两侧桩基水平位移在隧道范围内呈现明显"凹槽";盾构推力是影响桩基水平位移的重要因素,对沿隧道方向水平位移的影响较沿垂直隧道方向大,对桩基沉降影响较小;工程拟定袖阀管注浆加固措施将引起桩基产生附加沉降,对桩基水平位移控制无明显效果。分析结果认为,在不采取袖阀管注浆加固措施情况下,合理选取盾构推力,可完成盾构隧道对近接高架桥桩基的安全穿越。

Analysis of influence of adjacent viaduct pile foundation by Guangzhou metro tunnel shield driving under passing

This paper simulated influence of staged shield tunnel construction on adjacent viaduct pile foundations by using MIDAS/GTS 3D finite element analysis software,analyzed the development rule of horizontal displacement and settlement of pile foundations which provides the basis for the safe-passing of shield.The research indicated that horizontal deformation of bilateral pile foundations presents obvious "groove" on the range of tunnel,shield thrust is an important factor which affects the horizontal displacement of pile foundations,influence of which on horizontal displacement along tunnel direction is stronger than that along vertical tunnel direction,and has smaller effect on settlement of pile foundations.The sleeve valve barrel grouting reinforcement measure drafted by engineering will cause additional settlement of pile foundations,and has no significant effect on the horizontal displacement controlling of pile foundations.Combining with the obtained results,this paper concluded that the shield tunnel under-passing though viaduct pile foundations would be completed safely with no sleeve valve barrel grouting reinforcement measure if selecting the reasonable shield thrust.