离岸人工岛岛隧结合部沉管隧道基础沉降控制研究

Foundation Settlement Control Analysis of Immersed Tunnel at Connection between Offshore Artificial Island and Tunnel

为防止深中通道岛隧结合部暗埋段、E1管节、E2管节差异沉降过大,进而导致管节接头剪力键剪力及管节内力过大,通过对岛隧结合部沉管基础采取预加固措施,研究不同段落地基与基础参数,分析计算出E1管节预抬量合理值。通过室内试验及现场试验获取关键参数并开展大型三维有限元分析,研究管节应力及沉降特性。根据室内试验确定考虑预压30k Pa的1.0m厚碎石垫层变形模量取值为:0~30k Pa段为25.4MPa,30~110k Pa段为8.9MPa。根据现场试验确定块石垫层变形模量取值为50MPa。依据上述参数开展有限元分析,最终确定岛隧结合部沉管基础加固措施及管节的预抬量值为70mm。

To avoid overlarge difference settlement of the buried section,pipe E1,and pipe E2 at connection between island and tunnel of Shenzhen-Zhongshan link,and overlarge excessive shear of the shear key and the excessive internal force of the pipe joint,pre-reinforcement measures for the immersed tube foundation of the connection between island and tunnel are conducted,the foundation parameters of different sections are studied,and the rational pre-lift value of pipe E1 is analyzed and calculated.The key parameters are obtained through laboratory and field tests and large-scale three-dimensional finite element analysis is carried out to study the stress and settlement characteristics of the pipe.According to the laboratory test,the deformation modulus of 1.0 m thick crushed stone cushion with 30 k Pa preloading is determined to be 25.4 MPa in 0~30 k Pa section and 8.9 MPa in 30~110 k Pa section,respectively.According to the field test,the deformation modulus of the block rock cushion is 50 MPa.Based on the above parameters,the finite element analysis is conducted,and finally the reinforcement measures for the immersed pipe foundation are determined and the pre-lift value of the pipe is determined to be 70 mm.