Підсилення збірної залізобетонної оправи тунелю метрополітену для запобігання осіданню у слабких вміщувальних ґрунтах

Abstract

The effect of metro tunnel settlement on the opening of joints between segments of a precast reinforced concrete lining without tension ties is studied. An equation for estimating the joint opening width from surveying monitoring data is obtained: for a settlement of 25 mm the joints open by 0.55 … 0.70 mm, which exceeds the size of fine sand particles and explains soil washout into the tunnel. Strengthening by longitudinal reinforced concrete beams placed within the track concrete and anchored to the invert block is proposed. FEM analysis shows that it reduces settlement 1.55 times and internal forces in the lining 1.18 … 2.83 times without reducing the tunnel clearance.