SHIELD MACHINE FOR GRAVEL

摘要

PROBLEM TO BE SOLVED: To provide a shield machine for gravel capable of efficiently carrying out jacking work execution without blocking of clay in a chamber even in the case when the shield machine for gravel encounters a clay under ground a jacking method to construct a sewage pipe, etc., underground. SOLUTION: This is a shield machine for gravel furnished with a cutter surface plate 3 set on a head end of the shield machine free to rotate, a conical cone guide 4 arranged on the inside of an outer shell of the shield machine and an inside diameter of which becomes smaller backward from the rear of the cutter surface plate, a conical inner cone 6 arranged on the inside of the cone guide free to rotate to the rear of the cutter surface plate and an outer diameter of which becomes larger backward and a plural number of extension means 7 in the vertical direction against an inner peripheral surface and an outer peripheral surface with a specified interval at least on either one of the inner peripheral surface of the cone guide and the outer peripheral surface of the inner cone.