列车振动对基底存在空洞的盾构隧道全装配式内部结构的影响

Influences of Train Vibration on Integrated Assembled Internal Structures of Shield Tunnels Foundations on Cavities

盾构隧道内部结构的全预制化对于提高施工工效、保障建造质量具有重要意义。然而,由于装配构件的连接强度和质量存在差异,在隧底存在注浆空洞时铁路列车通行引起的振动响应将对装配式内部结构的受力和变形造成不利影响。以甬舟铁路金塘海底隧道为背景,提出全拼装内部结构与管片的两种连接方式(两端固接,一端固接一端水平铰接)及非封闭二衬部分拼装式内部结构,并对不同内部结构形式在列车振动下基底空洞对其基底累积沉降及内力的影响进行研究。研究表明:1)基底空洞导致基底累积沉降增大,但全装配式内部结构与管片在两端固接时盾构隧道累积沉降最小,表明内部结构与管片连接的加强能减小列车往复荷载作用下的累积变形;2)基底空洞会造成管片和结构内力的增大,造成该区域衬砌应力集中,阻碍振动能量往管片传递,造成全装配式内部结构的连接螺栓剪力幅值激增,并引起隧道拱底振动能量积聚,使振动的累积响应加剧。

The integrated prefabrication for internal structures of shield tunnels is of great significance to improve construction efficiency and guarantee construction quality.However,due to the difference in connection strength and quality of assembled components,the vibration response caused by the passage of the railway trains on shield tunnel foundations on cavities in tunnel basement will have negative effect on the force and deformation of the assembled internal structure.In view of this,taking the Against the background of Jintang Submarine Tunnel of Yongzhou Railway,two connection methods with segments(fixed at both ends,fixed at one end and horizontally hinged at the other end)of integrated assembled internal structures with shield segments and partially assembled internal structures with unclosedly secondary linings were proposed,we studied the influence of basal cavities in foundation under different internal structures on the cumulatively basal basement settlement and internal forces structural stress and deformation under vibration in operation of trains was studied.The research indicated that:1)Cavities under foundations would increase the cumuletively basal settlement,but the cumulatively basal settlement of the integrated assembled internal structure fixed with shield segments at both ends was minimum,it showed that the strengthening of the connection between the internal structure and the segments could reduce cumulative deformation under reciprocating loads by trains;2)Basal cavity causes the cumulative settlement of basement to increase,the integral assembled internal structure tied at both ends with segments can effectively reduce the cumulative basement settlement caused by basement cavity;2)Cavities under founndations would increase internal forces in shield segments and internal structures,and produce stress concentration in the lining in the corresponding area.internal forces in increase internal forces in segments and internal structures and produce stress concentration in Iinings in the corresponding area.Cavities would hinder transfer of vibration energy to segments,resulting in the sharp increase of shear amplitude in connecting bolts in the integrated assembled internal structure and the accumulation of vibration energy at the arch bottom,which would intensify the cumulative response of vibration.