摘要
港珠澳大桥沉管隧道上覆回淤厚度多达22 m,导致原先的节段式管节结构的失效概率大。为了降低风险,提出"半刚性管节结构"概念。通过不剪断原先节段式管节方案的临时预应力,来确保节段接头端面的摩擦力,从而用摩擦力与剪力键一同抵抗剪力,同时维持节段之间的相对转动能力;即令管节结构的健壮性得到提高。文章结合足尺物模试验对这个新结构优势进行了论证。对其中的关键问题预应力体系的设置进行了详述,并且报告了港珠澳大桥沉管隧道半刚性管节的应用案例。半刚性管节,相比节段式管节,在一些情况下,只是将临时预应力转变为永久预应力,施工费用未增加很多,但是管节的整体性与健壮性显著提高,因此半刚性管节是一种性价比较高的结构形式;特别对于水下基础施工质量控制困难,基础差异沉降不确定性大的工程,半刚性管节是值得考虑的一种管节纵向结构形式。
The overlying sediment on top of the immersed tunnel of Hong Kong-Zhuhai-Macao Bridge is up to 22 m,which leads to the high probability of failure of the structure of segmented type tunnel element. In order to reduce the risk,the concept of 'semi-rigid tunnel element'was proposed,The temporary pre-stressing tendon in the original segmented element scheme is not cut in order to secure the friction at connecting interface between segmented joints so the friction can work with the shear keys to resist the shear force,while the rotational abilities between segments are still ensured. In this way the robustness of element structure increases. This paper discusses the advantage of the new structure with the support of the full-scale physical model test. The critical issue the setting of prestressing system is discussed. Further more,the case of application of semi-rigid elements in the immersed tunnel of Hong Kong-Zhuhai-Macao Bridge is elaborated. Compared with the segmented type,in normal cases,in semi-rigid elements the temporary prestress tendons are changed into the permanent without considerable increase of cost but with considerably increased the integrity and robustness of the element,therefore,semi-rigid element is a cost effective structural form. In particular,for the project in which the submarine foundation works quality is difficult to control and differential settlement of foundation is of great uncertainty,semi-rigid element is worth considering as a type of longitudinal structural form of tunnel elements.
作者
林鸣
刘晓东
林巍
尹海卿
李毅
LIN Ming;LIU Xiao-dong;LIN Wei;YIN Hai-qing;LI Yi(CCCC HZMB Island and Tunnel Project General Management Office,Zhuhai 519015,China;CCCC HZMB Island and Tunnel Project General Office Design Division,Zhuhai 519015,China)
出处
《水道港口》
2018年第S2期1-13,共13页
Journal of Waterway and Harbor
关键词
沉管隧道
预应力
结构
回淤
深埋
摩擦力
immersed tunnel
prestress
structure
sedimentation
deep-buried
friction
