トンネル掘削における地下水位低下の効果に関する研究

抄録

For the shallow tunnel in sandy ground, an effect of drawing down of the ground water level for tunnel face stability is discussed in this paper. The effect was analyzed by means of rigid plastic FEA and Dupuit assumption. Using the numerical analysis, critical load factor was obtained and tunnel stability was evaluated. Drawing down of the ground water level makes relative gravity greater. In case of friction angle of ground material is greater than zero, the method is effective to increase the tunnel stability. Especially, it was confirmed that descending of ground water level from tunnel crown to spring line is the most effective to the stability.