Numerical Analysis of Tunnels in Expansive Soils

Abstract

The change of volume of expansive soil due to moisture content variations can lead to failure of structures built in it or on it. Numerical methods for analysis, e.g., finite element method have been widely used in analysis and design of tunnels. This research deals with the numerical analysis of tunnels erected in expansive soils to compute stresses and displacements by a viscoplastic finite element program (VISCOPLAST). Some modifications were made to this program to occupy the tunnel problems. The program applied for two cases of tunnels: without lining and with concrete lining. In addition to the above, the program managed to study the effects of many parameters of soil on the swelling process. The results obtained gave a good simulation to development of swelling process with time and its effects on the tunnel structures. The numerical technique adopted can predict the future behavior of swelling and its effects on underground opening.