JP2000282479A - Construction method for repairing existing catchment pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method for repairing an existing catchment pile which can be constructed efficiently, is excellent in economy, relatively excellent in safety, shortens the term of construction work, and gentle with natural environment. SOLUTION: Steel segments 3 obtained when a cylinder whose assembled form has an outside diameter slightly smaller than the interior wall of an existing water collecting pile is circumferentially and axially divided into plural portions, and a setting member (positioning and bearing member) 5 for use when the segments 3 are formed into a cylinder unit 4 and installed are prepared. These members are formed into the cylinder unit 4 on the ground with the setting member 5 located above, and are sequentially hung down whereby a cylinder made of steel plates is installed for use in repair.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing an aging existing drainage pit installed in a landslide area.

[0002]

2. Description of the Related Art An existing water collection pit has a shaft with an inner diameter of about 3 to 4 m and a depth of 20 to 30 m underground in a landslide area, and radially protrudes a water collection pipe into the surrounding ground, and at the bottom of the shaft. It has a structure with drain holes. The shaft is 0.7-1.5m in circumferential direction and 50cm in height, manufactured by bending a corrugated steel plate with a thickness of several mm into a curved surface.
Adjacent end flanges of a member called a liner plate are bolted to each other and protected by a cylindrically assembled wall material.

[0003] The existing drainage pit has been installed since the 1970s, and the old one has been deteriorated due to corrosion of the liner plate and the joining bolts, so that repair measures are required. As shown in FIG. 7, the repair method currently being carried out is such that, once the earth and sand 16 are put into the catchment pit 1 and backfilled, excavation is performed again from the upper side at a constant depth as in the case of the new construction. A method of dismantling and removing the old liner plate 2a that has deteriorated and replacing it with a new liner plate, and providing a new water collecting pipe 11 by horizontal boring is adopted. In this conventional method, the backfilled soil 16 is used as a work scaffold for preventing collapse of a collecting pit during operation.

[0004]

According to the above-mentioned conventional method, the existing drainage pit 1 is backfilled and re-drilled while the liner plate 2
In order to replace a, a large amount of earth and sand for backfilling is required, and there is a problem that digging, transporting / injecting and re-digging of backfilling earth require a great deal of labor and cost, and the construction period becomes long.
In addition, since most repair work is underground work, it is important to ensure safety against falling objects from above.

Further, the liner plate removed and collected
I was having trouble disposing of the remaining material in 2a. In addition, when using the surrounding soil excavated at the time of constructing the existing catchment pit 1 etc. as the backfill soil 16, the surrounding area has been several decades old, the vegetation has grown and the natural environment has been regenerated It will destroy the environment. The present invention solves the above-mentioned problems of the prior art, and provides a method for repairing an existing catchment pit that can be constructed efficiently, is economical, is relatively safe, can shorten the construction period, and is friendly to the natural environment. Aim.

[0006]

The method of repairing an existing catchment pit according to the present invention that achieves the above object is as follows. A steel segment 3 obtained by dividing a cylinder having an outer diameter slightly smaller than the inner wall 2a of the existing water collection pit 1 into a plurality of pieces in a circumferential direction and an axial direction, and forming the segment 3 into a cylindrical unit 4. In this method, a set member (that is, a positioning support member) 5 to be used for installation is prepared, and the existing drainage pit is repaired using these members in the following procedure. (1) Dismantle and remove the accessories in the existing drainage pit 1. (2) Assemble the segment 3 into a cylindrical shape on the ground, join it in the axial direction, and attach a set member (positioning support member) 5 in the circumferential direction at the upper end to form the cylindrical unit 4. (3) The first-stage cylindrical unit 4 is suspended and set on the water collecting basin 6 provided at the bottom of the existing water collecting pit 1 with the set member (positioning support member) 5 facing upward. (4) Hereinafter, the operation of forming the cylindrical unit 4 in the same manner, suspending the cylindrical unit 4 in the catchment pit 1, and installing the cylindrical unit 4 on the set member (positioning support member) 5 of the cylindrical unit previously installed. Repeat until the last stage. (5) Each time the cylindrical unit 4 of each stage is installed, or after all the cylindrical units 4 are installed, the backfill material 8 is filled in the gap 7 between the inner wall 2 of the existing collecting pit and the outer peripheral surface of the cylinder. (6) After installing the cylindrical unit 4 at the last stage, the boring device 9 is arranged at a predetermined position in the cylinder, horizontal boring is performed in the ground 10 outside the water collecting pit, and the water collecting pipe 11 is set.

The segment 3 to be used is manufactured by bending a flat steel plate having a thickness set according to the installation depth. The segment 3 may be provided with a number of small holes 12 in advance.

A set member (positioning support member) 5
Is a curved receiving material 5 for receiving the lower end 4b of the cylindrical unit 4
It is preferable that the mounting member 5a to be fixed to the end of the segment is formed in a T-shape, and the cushioning material 13 be sandwiched between the receiving member 5a and the lower end 4b of the cylindrical unit.

The gist of the present invention is as follows. Liner plate 2a of existing drainage pit 1 and existing drainage pipe 1 underground
1a is left as it is and is buried, and the existing water collecting pipe 11a is formed in the trap 14 in the existing water collecting pit 1 and in a portion protruding into the pit.
And the like, in which only the accessories that are arranged to protrude inside the existing collection pit 1 are dismantled and removed, and after securing the space inside the pit, the segments 3 are assembled on the ground outside the collection pit to form a cylindrical unit 4. Are sequentially suspended in the pit, and the existing drainage pit 1
Install a steel cylinder inside. And the existing collection pit inner wall 2
After filling the backing material 8 in the gap 7 between the and the cylinder, a boring device 9 is arranged at a predetermined position in the pit to pierce the ground 10 outside the pit, and a new water collecting pipe 11 is protruded and installed to repair the existing water collecting pit. Is what you do. In other words, since the cylindrical unit 4 formed by assembling the segments 3 has an outer diameter slightly smaller than the inner diameter of the inner wall 2 of the existing water collection pit, a decrease in space in the pit after repair can be reduced, and a reduction in water collection capacity is small. In addition, since the underground space can be widened, there is no hindrance to the insertion and arrangement of the boring device 9 for installing the water collecting pipe 11. In particular, when a flat steel plate segment is used, there is no uneven portion compared to a corrugated steel plate. In the present invention, if a large number of small holes 12 are provided in advance in the segment 3, permeated water can be collected from the outer periphery of the water collection pit 1. Further, since the set member (that is, the positioning support member) 5 is provided on the upper part of the cylindrical unit 4, the cylindrical unit 4 can be easily installed in the downhole.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of a drainage pit repaired by the method of repairing an existing drainage pit according to the present invention. The existing drainage pit 1 has a large number of liner plates 2a made of corrugated steel plates arranged in a staggered manner, and these are joined to form a cylinder, and the interior is a space. The bottom of the existing collecting pit (cylindrical) is connected to a concrete collecting basin 6 and a drain pipe 6a. A liner plate 2 is located in the middle of the existing drainage pit 1.
a through a plurality of existing collecting pipes 1 toward the underground ground 10.
1a (dotted line) is projected radially. The existing water collecting pipe 11a may be provided around the water collecting pit 1 in addition to being installed on one side as shown in the figure.

Since the existing drainage pit 1 has been built for several decades, a metal liner plate 2a holding the pit wall 2
And the existing water collecting pipe 11a is corroded, and the water collecting pipe is clogged and deteriorated. The present invention is carried out in the above-mentioned existing collecting pit 1 by leaving (filling) the deteriorated liner plate 2a and the existing collecting pipe 11a in the outer ground 10 as it is. A cylindrical unit 4 composed of a plurality of steel segments 3 having an outer diameter slightly smaller than the inner diameter is inserted into a pit, and is arranged in series in the vertical direction. Then, a back of sand, crushed stone, mortar, etc. The filling material 8 is filled, and a new water collecting pipe 11 is provided at a predetermined position for repair.

The segment 3 is divided into the above-mentioned cylindrical shape after assembly. The segment 3 is divided into two to four in the circumferential direction and a curved plate (arc-shaped plate in cross section) with several meters in the axial direction. The size is easy to handle and can be transported efficiently. When the number of segments in the circumferential direction of the segment 3 is made as small as possible,
It is desirable to divide into two (semicircle) to reduce welding and bolting work, but if the weight becomes heavy, it may be divided into three or four. When the segment 3 is formed by bending a flat steel plate, the amount of narrowing the underground space after the repair can be reduced, and the decrease in the water collecting capacity can be reduced.
Do not interfere with boring work when installing In this case, it is more economical to increase the plate thickness at a depth where the design external force is large and to reduce the thickness at a shallow portion. In addition,
If there is sufficient room for the collection capacity of the existing drainage pit and the installation work of perforated boring, the use of corrugated steel sheets can reduce the weight.

If a large number of small holes 12 are provided in the segment 3, it is possible to directly collect permeated water from the surrounding ground.
The small holes 12 need to be sized to prevent earth and sand from leaking. Further, it is desirable that the segment 3 be subjected to anticorrosion coating with a resin or the like. In this case, it is preferable that the outer surface be a tar epoxy coating containing glass flakes having good abrasion resistance and the inner surface be a tar epoxy coating.

When the water collecting pipe 11 is installed, a through hole may be made directly in the cylinder by the boring device 9.
If the arrangement of 1 is known in advance, it is better to make a hole 3a larger than the bore diameter of the boring or the outer diameter of the water collecting pipe 11 in the segment 3 in advance.

Each cylindrical unit 4 is vertically arranged in series via a set member 5. The set member (that is, the positioning support member) 5 allows the cylindrical unit 4 to be supported in a state where the cylindrical unit 4 is easily positioned while allowing the error to occur when the cylindrical unit 4 is mounted on the cylindrical unit 4 that is previously installed by hanging the unit in the downhole. The cylindrical unit 4 is provided at the upper end 4a of the cylindrical unit 4 to enable the work. As shown in FIG. 2, the receiving member 5a of the curved (annular) strip receiving the lower end 4b of the cylindrical unit and the segment 3 are provided. An attachment member 5b to be fixed to the end with bolts is fixed by welding to form a substantially T-shape. The set member 5 is fixed by bolts 5e inserted through bolt holes 4c provided at the upper end of the cylindrical unit 4 and bolt insertion holes 5d provided in the mounting member 5b of the set member 5. In addition, an upwardly projecting piece 5c is integrally provided on an inner peripheral end and an outer peripheral end of the receiving member 5a to facilitate installation of the cylindrical unit lower end 4b, and a cushioning material such as a rubber plate is annularly provided between the upper and lower cylindrical units 4. 13 so as not to form a gap. The set member 5 is manufactured by being divided into a circular arc shape in the circumferential direction or formed into a ring shape, and is manufactured by a steel plate or the like.

In the design of the water collecting pit 1, only the horizontal earth pressure applied to the outer peripheral surface of the cylinder is considered as the external force, and the bending moment and the horizontal shearing force in the height direction are not considered. However, the set members 5 may be provided at the upper and lower ends 4a and 4b of the cylindrical unit, and the set members 5 may be connected to each other by bolts. Backfill sand 8 is provided in the gap 7 between the liner plate 2a of the existing drainage pit 1 and the repair cylinder.
To keep the cylinder stable.

FIGS. 3 to 6 show the working procedure of the method of repairing the existing catchment pit according to the present invention and the members to be used. (1) First, as a preparatory work, a ramp 1 in the existing drainage pit 1
4. Dismantle and remove accessories such as the underground projecting part of the existing water collection pipe 11a (see a in FIG. 3). In addition, the aforementioned segment 3
Then, the set member 5 (see FIG. 3B) is carried to the site. (2) The segment 3 is assembled into a cylindrical shape on the ground, and a vertical edge of the end of the segment 3, that is, an axial dividing line 3b
The cylindrical unit 4 is formed by welding and joining each other (FIG. 4a).
reference). The segments 3 may be provided with bolted flanges along the axial dividing line 3b, and the flanges may be bolted to each other. Next, a set member (that is, a positioning support member) is provided in the circumferential direction of the upper end of the cylindrical unit 4.
5 (see FIG. 3b) is attached with bolts 5e (see FIGS. 4b and 2). (3) Assembling the tower 15 above the water collection pit 1 and installing a hanging device using a pulley (not shown) and a winch to set the first cylindrical unit 4 so that the set member 5 is on the upper side, and the water collection pit. 1 and is installed using a level adjusting material 20 on the catchment basin 6 provided at the bottom.

(4) Similarly, the second and subsequent cylindrical units 4 are formed on the ground in the same manner, suspended in the catchment pit 1, and installed on the set member 5 of the cylindrical unit 4 previously installed. Repeat the operation (see Fig. 5). (5) Each time the cylindrical unit 4 of each stage is installed, or after all the cylindrical units 4 are installed, the backfill material 8 is filled into the gap 7 between the existing collecting pit inner wall 2 and the outer periphery of the cylinder using a chute or the like. (See FIG. 6a). (6) After installing the cylindrical unit 4 at the last stage, a boring device 9 is arranged at a predetermined position in the cylinder, and horizontal boring is performed in the ground 10 outside the collecting pit to bore the hole. The water pipe 11 is installed. The boring device 9 may be installed on a temporary mounting as a working scaffold in the water collection pit, or use a table mounting 17 which is supported by engaging with the projecting portions (5a, 5c) of the set member 5. (See FIG. 6b). According to the above-described operation procedure, the above-described repair structure of the catchment pit shown in FIG. 1 is obtained.

[0019]

Embodiments of the present invention will be described below. Inner diameter 3.5
A specific example in which the repair method of the present invention is applied to an aging existing drainage pit having a depth of 30 m, a depth of 30 m and a diameter of a drainage pipe of 60 mm is as follows. The cylinder to be inserted and installed in the drainage pit 1 has an outer diameter of 3.3 m to ensure a gap of about 10 cm with the existing drainage pit wall for smooth insertion work.
Then, this is divided into segments 3 divided into two parts in the circumferential direction and ten parts in the depth direction, carried into the site, and assembled. That is, each segment 3 is manufactured by bending a rectangular flat steel plate having a circumferential direction of 5.2 m and a height direction of 3 m into a semicircular shape using a bending machine or the like. The bending may be performed in a factory, and the semicircular segments 3 may be stacked and transported to the site by truck transportation, or may be bent by a bending machine in which a flat steel plate carried in a plate shape is brought to the site. The plate thickness of the segment 3 is determined by the design external force set according to the installation depth, but about 25 mm is used for deep places and about 10 mm for shallow places. In each segment, a hole for a water collecting pipe having a diameter of about 80 mm is formed in advance at a position where the water collecting pipe 11 is installed. The segments are formed in the cylindrical unit 4 in the above-described procedure, installed in the catchment pit, and filled with the backfill material, and then the boring device 9 is directed toward the catchment pipe hole.
Is placed and a water collecting pipe is installed after drilling in the ground 10 outside the collecting pit.

According to the above embodiment, the capacity after the repair is reduced by only about 10% with respect to the water collection capacity of the catchment pit before the repair. In addition, since the underground space can be widened, drilling work for installing the water collecting pipe 11 becomes easy, and a boring device to be used
9 can also be used without special size.

[0021]

According to the method of repairing an existing catchment pit according to the present invention, segments formed on the ground outside the catchment pit and formed into a cylindrical unit are sequentially suspended in the pit, and a steel plate is placed in the existing catchment pit. Installation and repair, the underground work can be significantly reduced, work efficiency is good, and the construction period can be shortened.
In addition, since the underground work such as assembly is replaced with ground work, safety is easily ensured, and safety is further improved.

Further, since the outer diameter of the cylinder formed by assembling the segments used in the present invention is slightly smaller than the inner wall of the existing water collection pit, the reduction of the space inside the pit after repair can be reduced, and the reduction of the water collection capacity is small. In addition, the drilling work when installing the water collecting pipe is also facilitated. Furthermore, it can be said that the construction method is friendly to the natural environment without damaging the surrounding natural environment due to mining of a large amount of earth and sand.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of an existing drainage pit repaired by the repair method of the present invention.

FIG. 2 is a longitudinal sectional front view showing a state where a set member is attached.

3A and 3B are diagrams showing work procedures and members used in the repair method according to the present invention, wherein FIG. 3A is a partially longitudinal front view showing an existing catchment pit (attachment such as a ramp), and FIG. FIG. 4 is a perspective view showing a segment and a set member.

FIG. 4 is a perspective view illustrating a work procedure of the repair method according to the present invention, in which (a) is a perspective view illustrating a state of manufacturing a cylindrical unit, and (b) is a perspective view illustrating a state of attachment of a set member.

FIG. 5 shows a work procedure of the repair method according to the present invention, and is a partially cut-away longitudinal front view showing an installation state of a cylindrical unit.

6A and 6B show a work procedure of the repair method according to the present invention, wherein FIG. 6A is a partially longitudinal front view showing a backfill sand filling state, and FIG. 6B is a partial sectional view showing a water collecting pipe installation state. It is a notch longitudinal front view.

FIG. 7 is a partially longitudinal front view for explaining a conventional repair method.

[Explanation of symbols]

 1 ‥‥‥‥ Catchment pit 2 ‥‥‥‥ Inner wall of existing catchment pit 2a ‥‥‥ Liner plate 3 ‥‥‥‥ Segment 4 ‥‥‥‥ Cylinder unit 5 ‥‥‥‥ Set member 6 ‥‥‥‥ Catch basin 6a ‥‥‥ Drain pipe 7 ‥‥‥‥ Gap 8 ‥‥‥‥ Backfill material 9 ‥‥‥‥ Boring equipment 10 ‥‥‥‥ Outer ground 11 水 Water collection pipe 11 a ‥‥‥ Existing Water collecting pipe 12 ‥‥‥‥ small hole 13 ‥‥‥‥ cushioning material 14 ‥‥‥‥ ramp 15 ‥‥‥‥ turret 16 ‥‥‥‥ input sediment 17 ‥‥‥‥ stand 20 ‥‥‥‥ level adjustment material

Continued on the front page (72) Inventor Katsuhiko Iguchi 2-6-3 Otemachi, Chiyoda-ku, Tokyo New Inside Nippon Steel Corporation (72) Keita Nozaki 2-6-1, Otemachi, Chiyoda-ku, Tokyo New Nippon Steel Corporation (72) Inventor Tsunemasa Suzuki 1473-26 Ishikawacho, Hachioji-shi, Tokyo F-term (reference) 2D044 EA03

Claims (4)

[Claims] 1. A steel segment obtained by dividing a cylinder having an outer diameter slightly smaller than the inner wall of an existing water collecting pit into a plurality of pieces in a circumferential direction and an axial direction, and forming the segment into a cylindrical unit. A method of repairing an existing catchment pit, which comprises preparing set members to be used for installation, and repairing the existing catchment pit by using these members in the following procedure. (1) Demolition and removal of accessories in the existing catchment pit. (2) Assembling the segments into a cylindrical shape on the ground, joining them in the axial direction, and attaching a set member in the circumferential direction at the upper end to form a cylindrical unit. (3) The first-stage cylindrical unit is suspended and set on the catchment basin provided at the bottom of the existing catchment pit with the set member facing upward. (4) Hereinafter, a cylindrical unit is formed in the same manner, the cylindrical unit is suspended in the water collection pit, and the operation of installing the cylindrical unit on the set member of the cylindrical unit previously installed is repeated from the second stage to the final stage. (5) Each time the cylindrical unit of each stage is installed, or after all the cylindrical units are installed, the gap between the inner wall of the existing collecting pit and the outer peripheral surface of the cylinder is filled with the backfill material. (6) A boring device is arranged at a predetermined position in the cylinder, and horizontal boring is performed in the ground outside the collecting pit to set a collecting pipe. 2. The method according to claim 1, wherein the segments are formed by bending a flat steel plate having a thickness set according to the installation depth. 3. The method according to claim 1, wherein the segment is provided with a number of small holes in advance. 4. The set member has a curved receiving member for receiving the lower end of the cylindrical unit and a mounting member fixed to the end of the segment in a substantially T-shape, and a cushioning member is provided between the receiving member and the lower end of the cylindrical unit. 4. The method for repairing an existing catchment pit according to claim 1, wherein the material is sandwiched.