EFFECT OF THE NEW FORE PILING METHOD WITH MIDDLE LENGTH PIPES

Abstract

With regard to the current practice of tunnelling construction for railways and roads it is desired that a more practical method be developed so as to save time and cost as well as more safety. Lecentry, long forepiling method has been used widely so that the tunnel crown settlement in soil ground, can be restrained. On the other hand, cost by such method is generally high in case special technique or machine must be adopted. In addition, the effect by reinforcement using forepiling method is difficult to be made clear theoretically.
We developed a new forepiling method using middle length steel gas pipes for the purpose of lowering the construction cost with enough reinforcement effect. These reinforcement can be easily installed by conventional tunnelling machine. This paper reports the technical features and construction procedure. Next, the practical measuring results are shown. As a result, it is proved that the new forepiling method is effective in cost and reinforcement.