STUDY ON DEFORMATION INDUCED BY CRD METRO TUNNEL WITH LARGE CROSS-SECTION

A Changchun No.1 Metro Line station tunnel was constructed by CRD method with the character of large cross-section, shallow-buried. It's necessary to study the deformation of the stratum and the tunnel structure. Therefore, the numerical model founded by FLAC3D based on the geological conditions and construction conditions is contrasted with the monitoring data to study the deformation regularity. The result shows, the settlement curves of cross section and vertical section are fitted in Gauss formula well. The settlement of the ground surface is approximate to be elliptical funneled in three dimensional space, and the location of the largest ground settlement is near to the horsehead in the projection of the tunnel. During the excavation, the upmost pilot tunnels have made great influence to the final settlement, and it accounts about the half of the final settlement. Due to the median lamella reduces the tunnel convergence, monitoring the settlement of the ground surface and the vault is the predominant way to judge the stability of the tunnel. The above analysis conclusions have practical guiding significance for the construction of metro tunnel with large cross-section in the future.