超大断面箱形明挖隧道施工监测与力学特性分析  

Construction monitoring and mechanical property analysis for open-excavated box tunnel with super large cross-section

作　　者：欧孝夺[1,2] 吴红营[1,2] 黄颂扬[1,2] 唐迎春[1,2] 

机构地区：[1]广西大学,广西南宁530004 [2]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004

出　　处：《土木工程学报》2013年第7期133-140,共8页China Civil Engineering Journal

基　　金：国家自然科学基金(51168004);广西自然科学基金重点项目(2010GXNSFD013002)

摘　　要：结合超大断面四孔箱形明挖隧道(宽49.5m×高9.1m)的施工过程,选择典型断面布设混凝土应变计、沉降变形观测点等设备,开展隧道结构内力、结构沉降及变形等指标的监测。监测结果表明,超大断面箱形明挖隧道的主体结构,在两侧土压力的作用下,顶部荷载变化时,顶板和底板的混凝土应力均有变化,但底板变化的速度比顶板要慢且幅度比顶板小,而侧墙处于拉弯受力的不利状态,每节段纵向两端部位强度较薄弱。节段纵向墙体的共同特点为中间段混凝土受拉应力最大,其次是上段,下段受拉小;中墙混凝土应力较大,侧墙因受两侧土体约束影响应力较小。两侧不对称回填和上部不均匀覆土将造成墙体支座处混凝土拉压状况处于往复变化的不利状态。该研究结果对同类隧道结构施工力学及变形特性等研究具有参考价值。During the construction of open-excavated box tunnel with super large cross-section （width 49.5m×height 9.1 m） , lots of strain gauges and settlement observation points were installed on the typical sections of the structure, and some indexes, such asthe structural internal forces, the structural settlement and deformation were monitored. The results show that both the stress of concrete roof and floor change with the upside loads, but the change rate of the floor is smaller than that of the roof under the action of earth pressure on both sides. The side walls are under the composite actions of bending and tension stress and the intensity of each segment at the both ends of longitudinal section is weaker. The common characteristic of walls is that concrete strain in the middle is biggest, followed by upper, and the lower minimum. The concrete tensile strain is the bigger in the mid-walls and smaller in the side walls. The asymmetric backfill of both sides and non-uniform filling on top can lead to a disadvantage status, in which the tension and compression of supports reciprocate. The experiences and conclusions can provide reference for the study of construction mechanics and deformation properties of similar tunnels.

关 键 词：箱形隧道 超大断面 施工力学 覆土回填 

分 类 号：U456.3[建筑科学—桥梁与隧道工程]