Influence of Interior Column on the Behaviour of Quasi-Rectangular Tunnel

Abstract

The growing population in major cities around the world requires significant development of transportation infrastructure, especially underground system. It requires the construction of more subway lines, and larger tunnel cross-sections. In underground construction, a cross-sectional shape which is a combination of circular and rectangular tunnels is an advanced trend. This shape incorporates the advantages of both forms. There are two terminologies used to classify these shapes, including sub-rectangular and quasi-rectangular tunnels. While the sub-rectangular tunnel lacks an interior column, the quasi-rectangular tunnel includes an interior column located at the center of tunnel. Recent studies focus on separately investigating the behavior of sub-rectangular and quasi-rectangular tunnels using various methods such as numerical methods, analytical methods, and experimental methods. The present study conducted a numerical comparison of these two types of tunnels. The results indicated that the presence of an interior column help to increase the stability of the lining structure. The internal forces within the quasi-rectangular tunnel with an interior column are smaller than those of the sub-rectangular tunnel and quasi-rectangular tunnel without an interior column.