Method for injecting lubricant or back-filling material into a space between the outside of double-wall pipes and the ground in the pipe-jacking method and an apparatus therefor

A method of injecting lubricant or back-filling material into a space between the outside of double-wall pipes and the ground in a pipe-jacking process in which the double-wall pipes are propelled by a pipe-jacking machine,

• wherein a conduit comprised of double-wall pipes, each of which comprises an inner pipe and an outer pipe, is laid between a start vertical shaft and an arrival vertical shaft by propelling a tunneling machine followed by double-wall pipes by a pipe-jacking machine, the method comprising the steps of:
• providing each double-wall pipe with a sheath pipe between an inner pipe and an outer pipe of each double-wall pipe and with an intermediate layer which is filled in a space between the inner pipe and the outer pipe in such a manner that ends of the inner pipe are not covered with the intermediate layer, and mounting a check valve in an end of the outer pipe;
• propelling a double-wall pipe to such a position that a backward end of the double-wall pipe is protruded into the start vertical shaft with the inner pipe projecting further rearwardly than the outer pipe, and thereafter disposing a new double-wall pipe in the start vertical shaft, said new double-wall pipe initially having ends of its inner and outer pipes disposed axially from one another so that the ends of the inner and outer pipes are initially spaced axially from one another, connecting an end of the inner pipe of the double-wall pipe which has been propelled with a projecting end of the inner pipe of the new double-wall pipe;
• covering a space formed between an end of the inner pipe of the double-wall pipe which has been propelled and an end of the inner pipe of the new double-wall pipe, by propelling axially an outer pipe of the new double-wall pipe which is provided with the check valve until it contacts the outer pipe of said double-walled pipe which has been propelled;
• inserting an injecting member into the sheath pipe of the new double-wall pipe, and thereafter moving appropriately the injecting member in the sheath pipe, and injecting lubricant through the injecting member and the check valve into a space between the outside of the outer pipes and the ground, while propelling the tunneling machine followed by double-wall pipes;
• and
• after having laid a conduit comprised of double-wall pipes, inserting an injecting member into the sheath pipe and injecting back-filling material into a space between the outside of the double-wall pipes and the ground through the check valve.

A method of injecting lubricant or back-filling material into a space between the outside of double-wall pipes and the ground by laying a conduit comprised of double-wall pipes in the ground by a pipe-jacking method in which the double-wall pipes are propelled by a pipe-jacking machine, each of said double-wall pipes comprising an inner pipe and an outer pipe and being provided with a sheath pipe into which a lubricant or back-filling material supply pipe is inserted, between the inner pipe and the outer pipe and with a check valve through which lubricant or back-filling material is injected into a space between the outside of the double-wall pipes and the ground in the outer pipe, the method comprising the steps of:

• inserting a wire into the sheath pipe from one end thereof toward the other end thereof and the wire being connected with the lubricant or back-filling material supply pipe;
• thereafter, putting the lubricant or back-filling material supply pipe in the sheath pipe by drawing the wire so that an outlet of the lubricant or back-filling material supply pipe is opposed to the check valve;
• and
• sending lubricant or back-filling material to the check valve through the sheath pipe and injecting lubricant or back-filling material through the check valve into a space between the outside of the double-wall pipes and the ground.

A method of injecting back-filling material into a space between the outside of double-wall pipes and the ground in laying a conduit comprised of double-wall pipes in the ground by a pipe-jacking method in which the double-wall pipes are propelled by a pipe-jacking machine, wherein a conduit comprised of double-wall pipes, each of which comprises an inner pipe and an outer pipe, is laid between a start vertical shaft and an arrival vertical shaft by propelling a tunneling machine followed by double-wall pipes by a pipe-jacking machine, the conduit is provided with plural check valves which are disposed at intervals, the method comprising the steps of:

• inserting a back-filling material supply pipe provided with a back-filling material injecting member at the forward end thereof into a sheath pipe disposed between the inner pipe and outer pipe of the double-wall pipe, from one of the vertical shafts until an outlet of the back-filling material supply pipe arrives at a position at which the outlet of the back-filling material supply pipe is opposed to a central check valve disposed at about a center of the conduit;
• injecting back-filling material through the central check valve into a space between the outside of the double-wall pipes and the ground;
• thereafter moving toward another of the vertical shafts the back-filling material supply pipe until the back-filling material supply pipe reaches the next position at which the outlet of the back-filling material supply pipe is opposed to a next check valve adjoining the central check valve;
• injecting back-filling material through the next check valve into a space between the outside of the double-wall pipes and the ground;
• thereafter further moving toward the other vertical shaft the back-filling material supply pipe until the back-filling material supply pipe reaches other positions at which the outlet of the back-filling material supply pipe is opposed to other check valves while injecting back-filling material through said other check valves opposed to the outlet of the back-filling material supply pipe, and into a space between the outside of the double-wall pipes and the ground by which a space between the outside of the double-wall pipes and the ground is filled with back-filling material over about the half length of the conduit;
• thereafter inserting the back-filling material supply pipe from the side of the other vertical shaft into the sheath pipe until an outlet of the back-filling material supply pipe reaches a position at which the outlet of the back-filling material supply pipe is opposed to an inner most check valve which is disposed at a farthest position from the center of the conduit in a part of the conduit wherein a space between the outside of the double-wall pipe and the ground is not yet filled with back-filling material;
• injecting back-filling material through the inner most check valve into a space between the outside of the double-wall pipes and the ground;
• thereafter moving toward one vertical shaft the back-filling material supply pipe in the sheath pipe until the back-filling material supply pipe reaches the next position at which the outlet of the back-filling material supply pipe is opposed to next check valve adjoining the inner most check valve;
• injecting back-filling material through the next check valve into a space between the outside of the double-wall pipes and the ground;
• thereafter further moving toward another of the vertical shafts the back-filling material supply pipe until the back-filling material supply pipe reaches positions at which the outlet of the back-filling material supply pipe is opposed to check valves disposed adjacent the next check valve, injecting back-filling material through the check valve opposed to the outlet of the back-filling material supply pipe into a space between the outside of the double-wall pipes and the ground by which a space between the outside of the double-wall pipes and the ground is filled with back-filling material over the full length of the conduit.