【摘要】 以港珠澳沉管隧道天然地基段某一横断面为研究对象,对垫层厚度1 m及1.5 m的工况分别进行了模拟整个施工过程的离心模型试验及有限元计算研究,揭示了不同垫层厚度地基回弹再压缩应力应变特性、沉管结构的应变特征,为沉管隧道的施工及地基处理方案设计提供依据。结果表明,开挖卸荷基底产生拱形回弹;回填后基底应力及沉管底板应变均呈马鞍形分布;随时间及回淤增加,仅基底中部应力增大。垫层薄,基底应力分布匀化效果差,再压缩量及工后沉降增大。更多还原

【Abstract】 Taking one cross-section of the natural foundation in Hong Kong-Zhuhai-Macao immersed tube tunnel as research object,centrifugal model test and finite element simulation of the whole construction process in 1 m and 1. 5 m cushion layer thicknesses are carried out. The rebound and recompression stressstrain characteristics of foundation,strain characteristics of immersed tube structure with different cushion layer thicknesses are revealed to provides a basis for the design of construction and foundation treatment of immersed tube tunnel. The results show that( 1) excavation unloading makes basement produce arch distribution rebound;( 2) the stress distribution of base and the strain distribution of immersed tube bottom plate are the shape of a saddle after backfill;( 3) only the stress in the middle of base increased with time and silting;( 4) a thin cushion layer not only makes smoothing effect on basal stress distribution poor,but also increased the recompression quantity and post-construction settlement.更多还原