SIMPLE METHODS TO EVALUATE FACE STABILITY FOR SAND STRATA WITH CLAY LAYERS

Abstract

This paper describes simple methods to evaluate the conditions of tunnel face stability in sand strata that contain a clay layers by simulation of the model tests and the practice. As results, the followings were made clear: 1. The simple method (with friction) and the rigid-plastic finite element method can express the actual condition of face stability. 2. Murayama's Method and the simple method (with no friction) show the condition on the fairly safe side. 3. Simple methods can be applied to the practice if used properly.