Pipes and tubular conduits – Repairing – Patches
Reexamination Certificate
2002-10-31
2004-09-28
Hook, James (Department: 3752)
Pipes and tubular conduits
Repairing
Patches
C138S108000, C138S120000, C138S155000, C138S175000, C405S150100, C405S150200
Reexamination Certificate
active
06796334
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a conduit repairing material, a repairing structure and a repairing method using the same, and particularly relates to a repairing material for repairing degraded existing conduits such as sewer pipes, storm water pipes, and tunnels for various transportation modes, a repairing structure constructed by laying the repairing material, and a repairing method for installing the repairing material in an existing conduit.
BACKGROUND ART
When an existing conduit such as a sewer pipe, a storm water pipe, and a tunnel for various transportation modes is deteriorated, its repair is required depending on the degree of deterioration. When the deterioration of a conduit is minor, it is possible to repair it by applying mortar or other materials partly on the surface. However, when the deterioration is severe or widespread, the whole of a deteriorated conduit needs to be repaired with a repairing material.
Especially for repairing an existing conduit with a large diameter, it is effective to repair the entire conduit with a repairing material; and therefore such a repairing material and a repairing method for repairing an entire conduit are desired.
So far, several methods for repairing existing conduits such as a large diameter sewer pipe have been known.
For example, JP, A,8-277992 discloses a repairing method comprising: preparing a resilient reinforcing steel such as piano wire to be wound in a spiral form along the inner surface of an existing conduit, forming a tubular liner by winding a strip-like plastic plate over the reinforcing steel, and injecting a curable infilling (grouting material) such as mortar between the liner and the inner surface of the existing conduit. In this method, however, the reinforcing steel such as piano wire is not engaged with the plastic plate, and therefore the plastic plate itself is not reinforced. Therefore, when it is applied to repairing of a buried pipe, the curable infilling such as a mortar layer would be subject to cracks caused by vibrations due to vehicle passage or earthquakes. Thus, underground water will permeate through the cracks thereby directly applying water pressure against the plastic plate, and this may cause the plastic plate to bulge into the conduit at positions where the adhesion strength between the curable infilling such as mortar and the plastic plate is insufficient.
JP, A, 10-166444 discloses a repairing method which comprises: preparing a resilient strip-like plastic plate, which is to be formed into a liner by spirally winding it in an existing conduit, to bring it into engagement with a long reinforcing body containing a reinforcing steel, forming a liner by spirally winding the plastic plate along the inner surface of the existing conduit, and injecting a grouting material such as mortar between the liner and the inner surface of the existing conduit. In this method, although the plastic plate is reinforced by being integrated with a reinforcing body containing reinforcing steel in advance, it is not possible to employ a reinforcing body having a sufficient rigidity because the plastic plate needs to be spirally wound in the existing conduit. Therefore, when the existing conduit does not have enough strength, the reinforcement against the earth loads will not be sufficient.
In each of the above described conventional repairing methods for existing conduits, a reinforcing steel is utilized to raise the strength of the conduit after it is repaired; however, it is hardly assured that the plastic plate be reinforced to a sufficient level. Furthermore, when injecting mortar or the like between the existing conduit and the liner, it is necessary to place a supporting on the inner surface of the liner or to perform grouting with mortar or the like in several split operations adding one after another to prevent the deformation of the spirally wound plastic plate due to the pressure of the injection. And this would make the execution of the laying operation complex and time consuming.
On one hand, conventionally, there is known a construction method in which a lining material is laid along the inner surface of an existing conduit, and a grouting material such as mortar and cement milk is injected into a gap between the lining material and the inner surface of the existing conduit to be cured.
This type of construction methods, as disclosed, for example, in JP, A, 63-88388, typically utilizes a repairing method which comprises: preparing an injection hose to be inserted into a tubular gap formed between the inner surface of an existing conduit and the lining material, filling the opening parts of the tubular gap at its both ends in the lengthwise direction with mortar for sealing, and in that state, injecting a grouting material into the tubular gap through the injection hose.
However, in the conventional method in which a grouting material is injected in a state that the opening parts at both ends of the gap between the inner surface of an existing conduit and the lining material are sealed up with mortar, it was impossible to start injecting the grouting material until the sealing mortar is cured, and also it was required to conduct the injection of the grouting material at a low pressure since the sealing by the mortar may be destroyed due to the pressure during the injection of the grouting material. Moreover, when water is flowing inside the existing conduit, it is difficult to apply complete sealing with mortar, and thus the grouting material may flow out through part of the sealing. For these reasons, the conventional construction method in which both ends of the gap are sealed up with mortar had a problem in that the operation of injecting the grouting material is inefficient and time consuming.
DISCLOSURE OF THE INVENTION
In order to solve the above described problems, it is an object of the present invention to provide a repairing method for an existing conduit, in which the inner face bar such as a plastic plate forming the inner surface of the repaired conduit will not be directly subject to exterior water pressure, the existing conduit will be reinforced even when it has a low strength, and repairing work can be easily carried out without need of counter measures such as placing a supporting when injecting a curable infilling (grouting material) such as mortar, and also to provide a repairing material to be used for the method and the repairing structure obtained by the repairing method.
It is another object of the present invention to provide a grouting structure for the end parts of a repairing material for a conduit, whereby the end parts of the gap into which the grouting material is injected can be securely sealed up without being affected by the surface conditions of the existing conduit such as running water, the injection of the grouting material can be performed stably at a high pressure, and moreover a high quality of the grouting material after curing can be secured.
To achieve the above described objective, the present invention provides a repairing method for an existing conduit, characterized by comprising: preparing a plurality of reinforcing members capable of being carried into the existing conduit, assembling the reinforcing members into a hollow skeleton-like reinforcing body extending substantially along the inner surface of the existing conduit, attaching a plurality of inner face bars to the inside of the reinforcing body to assemble then into a tubular form along the length of the existing conduit, and thereafter injecting a curable infilling into a gap between the inner face bar and the inner surface of the existing conduit.
In the repairing method for an existing conduit according to the present invention, it is possible to adopt a method in which a plurality of fixing bars are attached to the inside of the above described reinforcing body, and the above described inner face bars are fitted into the fixing bars. When using such fixing bars to attach the inner face bars onto the reinforcing body, the fixing bar is preferably a long member conti
Ishikawa Masatoshi
Makimoto Futoshi
Saito Hitoshi
Ashimori Industry Co. Ltd.
Hook James
Wolf Greenfield & Sacks P.C.
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