Study for planing and effects of vertical forepoling bolt method on the slope with thin overburden

Abstract

This paper shows the decision making and the planing of the vertical forepoling bolt method in auxiliary methods for tunneling under thin overburden with unsymmetrical earth pressure. Auxiliary methods are applied to avoid the ground settlement, collapse at the cutting face and landslide. It is important to decide proper supporting at the site with imperfect arch action or low bedrock strength such as tunnel portal or shallow overburden. As a guide to control those problems, the vertical forepoling mechanism is evaluated through the monitoring system for slope stability by using back analysis with field measurement data in this paper.