THREE DIMENSIONAL NUMERICAL INVESTIGATION OF BAGHDAD METRO PASSING UNDER TIGRIS

Because of increased public concern regarding the impact of tunnelling on surface waterways under which tunnel passes and on surrounding environments, the effect of interaction between tunnelling and ground water on the soil around boring tunnel and ground surface has become an essential part of the planning, design, and construction of tunnelling project. In this paper, the commercially available finite element package, Abaqus 2016, is used to simulate the behaviour of the proposed Baghdad metro passing under Tigris before and after tunnel excavation by using a fully coupled three dimensional stress-pore pressure finite element model to realistically capture the mechanical and hydrological interaction between the tunnelling and ground water. It is found that maximum vertical displacement occurs at the crown with value equal to 4.25 m approximately to the downward after one year of liners installation. It is shown that there are significant differences in pore water pressures for soil surrounding around tunnel before, during, and after tunnel excavation. It is also shown that the head of water in river has significant difference before, during, and after tunnel excavation.