超大直径水下盾构隧道近接施工力学行为分析

为探明海域复合地层条件下,水下超大直径盾构公路隧道近距离开挖对既有隧道的影响,文中以珠海横琴马骝洲交通隧道为研究背景,采用数值计算和现场试验相结合的方法,得到了由盾构施工引起的既有隧道附加内力及变形变化规律。分析数据可知:盾构施工会引起管片的二次附加内力,拱顶弯矩和拱底轴力受隧道开挖的影响程度较大;由开挖引起地表沉降影响范围约为5倍隧道洞径,盾构在近距离施工产生的荷载对既有隧道有挤压变形的效果,两侧拱腰会随着隧道掘进而逐渐向内产生二次收敛变形。

Analysis on Mechanical Behaviors of Proximity Construction of Super Large Diameter Underwater Shield Tunnel

In order to ascertain the impact of short-distance excavation of an underwater super-largediameter shield highway tunnel on an existing tunnel under the condition of composite stratum in the sea area,in this paper the Zhuhai Hengqin Maweizhou transport tunnel is taken as the research background,and a combination of numerical calculation and field tests are used to obtain the law of additional internal force and deformation of the existing tunnel caused by shield construction.According to the analysis data,the shield construction cause the secondary additional internal force of the segment,the arch moment and the axial force at the bottom of the arch are greatly affected by the tunnel excavation.The surface settlement range caused by the excavation is about 5 times of the tunnel diameter,the load generated by the shield construction at a short distance has the effect of squeezing deformation on the existing tunnel,and the arch waist on both sides gradually deform inwards along with the excavation of the tunnel.