地铁双隧道施工诱发地表沉降预测研究与应用

Prediction for GroundSubsidence Induced by Subway Double Tube Tunneling

地铁施工诱发地层沉降与环境损伤的预测与控制是亟待深入研究的重要课题.地铁区间隧道多是同一埋深建造的两条近距离平行隧道,两隧道开挖对地层沉降的影响往往相互叠加,沉降预测更加困难.本文研究了双孔平行隧道施工诱发地表横向及纵向变形的修正Peck法与随机介质法计算公式;对于地铁双孔平行隧道开挖,基于部分实测沉降数据的Powell最优化理论方法,实现了Peck法与随机介质法各自的多参数反分析预测;开发出了地铁隧道施工诱发地层环境损伤预测评价与控制设计的STEAD系统;对多处双孔平行隧道工程实进行了理论预测和验证,实测沉降证明了理论方法与STEAD程序系统的科学性和有效性.

The prediction and control of the ground surface subsidence are ones of the most crucial problems in all environmental damages induced by subway tunneling excavation. The subway tunnels are usually excavated and constructed as double parallel tube tunnels at the same buried depth. The space between the double tunnels is generally short distance. The ground subsidence-lnduced by two staged tunneling is usually overlapped and is also hard to predict consequently. On the basis of stochastic medium model and revised Peck ground volume-loss model, this paper presents the analytical formulation for cross sectional and longitudinal ground subsidence prediction for double parallel tube tunneling. The Powell optimization theory was employed for subsidence back-analysls for double tube tunneling using fractional field measured settlement results. The multi-parameters back-analysis for both stochastic medium model and Peck model can be fulfilled easily. Furthermore, a subway tunneling induced ground-envirdnment damage assessment and controlling design （STEAD） software code was developed and in troduced. Finally, two case studies for the double parallel tube tunneling projects were carried out to verify the validity and reliability of the proposed theory approaches and software system.