Abstract
This paper aims to analyze stability of parallel tunnels on each stage of tunneling, to make clear the relations between stability and various physical values of ground and support. The stability of parallel tunnels is descussed from the point of distortional strain energy by stress function of bipolar coordinates. The preliminaly design method of parallel tunnels supported by shotcrete and rock bolts is presented. The results are applied to actual data of parallel tunnels, and then the relations between elastic constant of ground at the front tunnel excavation and that at the rear one is proposed.
