大断面过江隧道运营期受力变形健康监测分析

Monitoring and analysis of force and deformation of large section crossing-river tunnel during operation period

在采用国外的精密监测设备,对杭州庆春路过江隧道这一大直径的过江隧道结构进行长期健康监测的基础上,得到穿越砂性土层大断面隧道在运营期的横断面的受力和变形特性,分析隧道上部潮位变化和河床冲刷对隧道钢筋内力、界面压力、隧底沉降等的影响.实测数据表明:在运营期车辆荷载和潮水荷载作用下,由于施工期土体扰动影响,隧道纵断面沉降及管片与土体界面压力随着时间的推移而逐渐累增,大约半年后达到稳定;内外弧钢筋的受力变化情况和隧道直径变形基本不变.隧道沿线的沉降量受下卧层的性质影响较大.短时间内的钱塘江涌潮作用对过江隧道粉砂性土层段拱底沉降有一定的影响,直径变形、钢筋内力、界面压力等的变化不太明显.

The foreign precision monitoring equipment was used for long term health monitoring in the large diameter tunnel of Hangzhou Qingchun-road. The force and deformation of the large section tunnel which was lying in the sandy strata during operation period were analyzed and summarized based on field monitoring data from Qingchun-road crossing-river tunnel in Hangzhou. The effect of tidal and scour on the tunnel reinforced internal force, the interface force and tunnel settlement was analyzed. Data show accumulations of both longitudinal settlement of tunnel segments and the earth pressure distribution around the tunnel lining under the loads of both traffic and tide which result in soil disturbance in the construction period. The settlement becomes stable after about six months. However, the force on the steel bars and the deformation of the tunnel diameter remain unchanged. The substratum greatly influences on the longitudinal settlement of tunnel segments. The settlement of tunnel invert in sandy substratum is obviously affected by the tide of Qiantang River for short time, while slight changes appear in the deformation of tunnel diameter, stress of steel bar and earth pressure distribution.