Control Measures and Corresponding Effectiveness for Tunnel Heave Induced by Long Collinear Overlying Excavation
Overlying excavation causes stress relief in the soil above an underlying tunnel,which easily induces tunnel heave and affects the serviceability of the tunnel.Based on the reconstruction project of Guimiao Road in Shenzhen,this paper proposes differential countermeasures for the underlying tunnel heave subjected to overlying excavation in different sections and verifies the effectiveness of the measures via field measurements.The results showed that as the distance to the excavation center decreases,the heave of the underlying tunnel and the unloading rate of the soil increase.When the excavation area is more than 30 m away from the tunnel,the excavation-induced soil stress relief does not significantly affect the tunnel deformation.In various excavation areas,longitudinal segmentation + vertical stratification + separate excavation for left and right side;longitudinal segmentation + vertical stratification + separate excavation for left and right side + reinforcement of high-pressure jetting piles,and spaced shaft excavation + anti-heave frame were adopted.Furthermore,the measured data showed that the maximum unloading rate of soil mass was 0.52,and the maximum uplift of the tunnel was 13.4 mm.This indicated that the effectiveness of these measures was generally satisfactory.This study offers valuable insights into similar projects.
NETL
NSTL
万方数据
维普
