JP5653812B2 - Rehabilitation method for existing collection wells and rehabilitation collection well constructed by the method - Google Patents

Description

  The present invention relates to a rehabilitation method for an existing water collection well that is rehabilitated in an installed state without dismantling an old water collection well that has deteriorated and deteriorated in strength, and a rehabilitation water collection well constructed by the method.

Conventionally, in order to remove groundwater in the ground that causes landslides, drainage wells have been used to collect drainage wells on ground where landslides are likely to occur, collect groundwater, and discharge them to rivers (for example, patent documents) See 1-2.)
This drainage well usually excavates a vertical shaft with a diameter of 3 m or more by preventing collapse of the well wall with a steel liner plate, and installs a water collecting pipe through the liner plate from the excavated vertical shaft, The groundwater in the ground is collected in a collection well through this water collection pipe, and discharged from the collection well to a river or the like through a drain pipe.

Japanese Patent Laid-Open No. 8-184094 JP 2008-19679 A

  By the way, as described above, since the conventional water well is made of a steel liner plate, there is a problem that the strength decreases due to corrosion due to secular change, and the function of the water well cannot be performed due to collapse of the well wall.

As a method for rehabilitation of a drainage well with reduced strength, it is conceivable to replace the liner plate with reduced strength with a new liner plate. However, the strength of the drainage well constructed on a soft ground where landslides are likely to occur is limited. The replacement of the lowered liner plate was problematic in terms of safety.
It is also possible to install a rehabilitation pipe made of steel or concrete pipe having the required strength inside the drainage well, but this work must be carried out by bringing large heavy machinery into the soft ground where landslides are likely to occur. There was a problem in construction, and there was a problem that it was difficult to install a water collection pipe through a rehabilitation pipe whose inner diameter was smaller than that of an existing water collection well.

  In view of the actual situation of the conventional existing well, the present invention is constructed by rehabilitating an existing drainage well that can be rehabilitated without dismantling the existing drainage well that has deteriorated and deteriorated in strength. The purpose is to provide a rehabilitation collection well.

  In order to achieve the above-mentioned object, the rehabilitation method for an existing catchment well according to the present invention includes a rehabilitation pipe installation step of standing a synthetic resin rehabilitation pipe with a space inside the existing catchment well, and a pipe wall of the rehabilitation pipe Extension water collecting pipe extending process to connect the extended water collecting pipe penetrating the existing water collecting pipe to the water collecting pipe of the existing water collecting well, and filling material placing process for placing the filler in the space between the existing water collecting well and the rehabilitation pipe It is characterized by.

  In this case, one existing drainage well can be rehabilitated by repeating the rehabilitation pipe installation process, the extended water collection pipe extension process, and the filler material placement process as one cycle for a plurality of cycles.

  Moreover, the self-supporting type pipe material which can hold | maintain a shape can be used for a rehabilitation pipe | tube.

  Moreover, a through-hole can be formed on-site at a position corresponding to a water collection pipe of an existing water collection well on the pipe wall of the rehabilitation pipe.

  Moreover, after rehabilitating the water collection pipe of an existing water collection well, a rehabilitation pipe installation process, an extended water collection pipe extension process, and a filling material placing process can be performed.

  Moreover, the rehabilitation water well of this invention is constructed | assembled by the rehabilitation construction method of the said existing water well.

The rehabilitation method for an existing water collection well according to the present invention and the rehabilitation water well constructed by the method have the following advantages.
(1) Since existing drainage wells that have deteriorated and have a reduced strength can be rehabilitated without dismantling them, the safety of construction is high.
(2) Since the rehabilitation pipe made of synthetic resin is remarkably light compared to the rehabilitation pipe made of steel pipe or concrete pipe, there is no need to bring large heavy machinery into the soft ground where landslides are likely to occur. In addition, it is resistant to corrosion due to aging and is durable.
(3) By connecting an extension water collection pipe that penetrates the wall of the rehabilitation pipe to the water collection pipe of the existing water collection well, the water collection pipe can be easily installed even if a rehabilitation pipe whose inner diameter is smaller than that of the existing water collection well is used. In addition, the thickness of the filler layer to be placed in the space between the existing drainage well and the rehabilitation pipe can be set to an arbitrary thickness that exhibits the required strength in combination with the rehabilitation pipe.
(4) The rehabilitation pipe installation process, the extended water collection pipe extension process, and the filling material placement process can be repeated as a single cycle for a plurality of cycles, whereby the existing drainage well with a large depth can be rehabilitated easily. .
(5) By using a self-supporting tube material that can maintain the shape of the rehabilitated tube, there is no need for reinforcement work for placing the filler material, and the temporary work can be of a simple structure such as a working scaffold.
(6) The rehabilitation pipe made of synthetic resin can be made to form a through-hole in the site corresponding to the water collection pipe of the existing water collection well on the wall of the rehabilitation pipe, and easily corresponds to the existing water collection well. be able to.
(7) After rehabilitating the water collection pipe of the existing water collection well (including cleaning and reinforcement and new installation), the rehabilitation pipe installation process, the extended water collection pipe extension process and the filling material placing process will be carried out. The water collecting function of the water collecting well can be enhanced.

It is explanatory drawing which shows one Example of the work process of the rehabilitation method of the existing collection well of this invention. It is explanatory drawing which shows one Example of the work process of the rehabilitation method of the existing collection well of this invention. An example of the synthetic resin rehabilitation pipe | tube used for the rehabilitation method of the existing collection well of this invention is shown, (a) is whole explanatory drawing, (b) is explanatory drawing of a junction part.

  Hereinafter, the rehabilitation method for an existing water collection well according to the present invention and an embodiment of the rehabilitation water well constructed by the method will be described with reference to the drawings.

In FIG. 1, one Example of the operation | work process of the rehabilitation method of the existing drainage well of this invention is shown.
The rehabilitation method for the existing drainage well consists of a rehabilitation pipe installation process in which a synthetic resin rehabilitation pipe 2 is erected with a space inside the existing drainage well 1, and an extended water collection pipe penetrating the pipe wall of the rehabilitation pipe 2 The extension water collecting pipe extending step for connecting 21 to the water collecting pipe 11 of the existing water collecting well 1 and the filling material placing step for placing the filler 3 in the space between the existing water collecting well 1 and the rehabilitating pipe 2.

In this rehabilitation method for existing catchment wells, prior to the rehabilitation pipe installation process, in the pretreatment process shown in Figs. 1-1 (1) and (2), Ancillary equipment 12 such as a trap is removed (for the water collection pipe 11, the length is adjusted and a socket for connection to the extended water collection pipe 21 is attached to the end), and the bottom of the existing water collection well 1 is attached. The foundation 4 for constructing the rehabilitation pipe 2 is constructed by excavating and placing concrete.
In this case, the detailed internal structure such as the position of the water collection pipe 11 of the existing water collection well 1 is measured by surveying, the clogging or breakage of the water collection pipe 11 is confirmed, and the water collection pipe 11 is backwashed or the like. By relieving clogging or laying a new water collecting pipe 11, the water collecting pipe 11 can be rehabilitated, thereby improving the water collecting function of the water collecting well.
And, in this way, the liner plate is installed as it is without dismantling the existing drainage well 1 that has deteriorated in strength (the upper cover 23 described later is installed for the liner plate above the existing drainage well 1). May be removed from the relationship, etc.), so that the safety of the construction will be high.

Next, in the rehabilitation pipe installation process and the extended water collection pipe extension process shown in FIG. 1-1 (3), a synthetic resin rehabilitation pipe 2 is set up on the foundation 4 with a space inside the existing water collection well 1. Set up.
The rehabilitation pipe 2 uses a self-supporting pipe material that can retain its shape, so that there is no need for reinforcement work for placing the filler, and the temporary work 5 is constructed of a simple structure such as a work scaffold. Installation to the inside can be stopped, and the temporary construction 5 can be easily assembled and disassembled.
Here, the rehabilitation pipe 2 made of synthetic resin is extremely light compared to the rehabilitation pipe made of steel pipe or concrete pipe, so there is no need to bring large heavy machinery into the soft ground where landslides are likely to occur. In addition, it is resistant to corrosion due to aging and is durable.

The synthetic resin rehabilitation pipe 2 can be an existing synthetic resin pipe, but a pressure-resistant polyethylene rib pipe (JISK6780) (Howell pipe shown in FIG. 2, for example, Howell pipe manufactured by Dainippon Plastics Co., Ltd.). ) Can be suitably used.
This pressure-resistant polyethylene rib pipe has a hollow rib structure and has both rigidity and light weight, and a fiber reinforced pipe can be used if necessary.
In addition to the rubber gasket 2a, the pressure-resistant polyethylene rib pipe can be joined by welding, electrofusion, or the like, and can easily cope with the existing drainage well 1 having a large depth.

In the extension water collection pipe extension process, a hole is drilled in the pipe wall of the rehabilitation pipe 2 at the position of the water collection pipe 11 of the existing water well 1 measured by surveying in the pretreatment process (the rehabilitation pipe 2 made of synthetic resin is Drilling can be carried out with the water collecting pipe 11 of the existing drainage well 1 on the wall of the rehabilitation pipe 2, but drilling can also be carried out in advance in the factory.) An extended water collection pipe 21 is laid through the pipe wall of the pipe 2 and connected to the water collection pipe 11 of the existing water well 1.
In this case, in order to locate the drilling location, in addition to using the measurement results of the surveying performed in the pretreatment process, the measurement equipment is installed on the ground and the rehabilitation pipe 2 is raised to a position where it can be measured. Measure the standing position of the pipe 2, calculate the coordinates of the point (drilling location) where the collection pipe 11 and rehabilitation pipe 2 of the existing drainage well 1 overlap, mark the point, and drill To do.
The connection between the water collecting pipe 11 and the extended water collecting pipe 21 of the existing water collecting well 1 is performed by operating the extended water collecting pipe 21 from the inside of the renovated pipe 2 by attaching a socket to the end of the water collecting pipe 11 in advance. be able to.
Moreover, the extended water collecting pipe 21 laid through the pipe wall of the rehabilitated pipe 2 is fixed to the pipe wall of the rehabilitated pipe 2 using a general-purpose closing member.
In this way, even if the regenerator pipe 2 whose inner diameter is smaller than that of the existing catchment well 1 is used by connecting the extended catchment pipe 21 penetrating the pipe wall of the reclaimed pipe 2 to the catchment pipe 11 of the existing catchment well 1. The extension water collection pipe 21 can be easily installed, and the thickness of the filler layer placed in the space between the existing water collection well 1 and the rehabilitation pipe 2 is combined with the rehabilitation pipe 2 to provide the necessary strength. You can set it to any thickness you want.

Next, in the filling material placing step shown in FIG. 1-2 (4), the filling material 3 is placed in the space between the existing drainage well 1 and the rehabilitation pipe 2 using the filling material injection plant 6.
It is desirable that the filling material 3 be placed in several steps so that the rehabilitated pipe 2 does not float due to buoyancy.
As the filler 3, any filler such as concrete, air mortar, cement bentonite and the like can be used.
Further, in order to reinforce the strength of the filler 3, a reinforcing rod (not shown) can be installed in the space between the existing water collection well 1 and the rehabilitation pipe 2 prior to the laying of the extension water collection pipe 21.

  Next, in the finishing step shown in FIG. 1-2 (5), the temporary work 5 is dismantled and removed, and the auxiliary equipment 22 such as a trap and an intermediate stage and the upper cover 23 are installed to complete the construction.

In this embodiment, the rehabilitation pipe installation process, the extended water collection pipe extension process, and the filler material placement process are each completed in one operation, but the rehabilitation pipe installation process, the extended water collection pipe extension process In addition, the filling material placing step can be repeated as a single cycle for a plurality of cycles.
Thereby, the existing drainage well 1 with a large depth can be rehabilitated easily.

Hereinafter, the relationship between the existing drainage well 1 and the regenerated pipe 2 made of synthetic resin will be described based on more specific examples.
・ Diameter of existing drainage well 1: φ3500, φ3000
・ Nominal diameter of rehabilitation pipe 2 made of synthetic resin (Howell pipe made by Dainippon Plastics): φ2400, φ2000
-Outer diameter of synthetic resin rehabilitation pipe 2 (Dainippon Plastics Howell pipe): 2700 mm (φ2400), 2300 mm (φ2000)
-Length of rehabilitation pipe 2 made of synthetic resin (Howell pipe made by Dainippon Plastics): 5 m, 2 m, 1.5 m
・ Weight of plastic rehabilitation pipe 2 (Dainippon Plastics Howell pipe): 2600-500 kg
-Self-supporting height of rehabilitation pipe 2 made of synthetic resin (Howell pipe made by Dainippon Plastics): 18 m (φ2400), 50 m (φ2000)

Next, an example of the examination result of structural calculation (buckling and compressive force) is shown.
(1) Buckling (1-1) When filling of filler is completed The allowable buckling load qa when the ring receives a uniform load is calculated by the following equation.
The lateral pressure is calculated on the assumption that it is supported by the rehabilitation pipe 2 made of synthetic resin (Howell pipe made by Dainippon Plastics) and the filler 3.
qa = 2 × (EP × IP + EC × IC) / r ³
qa: allowable buckling load EP: Young's modulus of rehabilitation pipe 2 made of synthetic resin (Howell pipe made by Dainippon Plastics) 9.8 × 10 ⁵ (kN / m ² )
IP: Second moment of inertia of Howell tube
Tube thickness t = 0.086 (m)
^{I = t 3/12 5.31 ×} 10 -5 (m 4 / m)
EC: Young's modulus of filler 3 10 × 10 ⁵ (kN / m ² )
IC: Cross-sectional second moment of backfilling material
Tube thickness t = (2.8-2.4-0.086 × 2) /2=0.11 (m)
^{I = t 3/12 1.11 ×} 10 -4 (m 4 / m)
r: shaft radius (1/2 of Howell tube inner diameter) 1.2 (m)
qa = 2 × (9.8 × 10 ⁵ × 5.31 × 10 ⁻⁵ + 10 × 10 ⁵ × 1.11 × 10 ⁻⁴ ) / (1.2) ³ = 188.7 (kN / m ² )
Ph: Design side pressure 155 (kN / m ² )
Since the allowable buckling load qa is larger than the design side pressure Ph, the structural calculation (buckling) is satisfied.
(1-2) During injection of filler Pc: Side pressure of filler 3 (kN / m ² )
H: Height of casting material 3 15 (m)
γc: specific gravity of filler 3 11 (kN / m ³ )
Pc = H × γc = 15 × 11 = 165 (kN / m ² )
qa = 2 × (9.8 × 10 ⁵ × 5.31 × 10 ⁻⁵ ) / (1.2) ³ = 60.22 (kN / m ² )
Since the allowable buckling load qa is smaller than the side pressure Pc of the filler 3, the structural calculation (buckling) is not satisfied.
Therefore, the upper limit of the single placement height H2 of the filler 3 is
H2 = qa / γc = 5.47 (m).
(2) Compressive force N = Ph × r
N: axial force (kN / m)
Ph: Design side pressure 155 (kN / m ² )
r: shaft radius (1/2 of Howell tube inner diameter) 1.2 (m)
N = 155 × 1.2 = 186 (kN / m)
Examination of compressive stress of Howell tube σ1 = N / A1 ≦ σ0
σ1: Compressive stress degree of Howell tube N: Axial force 186 × 10 ³ (kN / m)
σ0: allowable stress degree of Howell tube 16.2 (N / mm ² )
A1: Cross-sectional area of Howell tube 86 × 10 ³ (mm ² )
σ1 = 186/86 = 2.16 (N / mm ² )
Bending yield stress of Howell tube 32.4 (N / mm ² )
Since the compressive stress σ1 of the Howell tube is smaller than 1/2 of the bending yield stress of the Howell tube, the structural calculation (compressive force) is satisfied.

  As mentioned above, although the rehabilitation construction method of the existing collection well of this invention and the rehabilitation collection well constructed by this construction method were explained based on the example, the present invention is not limited to the composition indicated in the above-mentioned example. The configuration can be changed as appropriate without departing from the spirit of the invention.

  The rehabilitation method of the existing water collection well of the present invention and the rehabilitation water well constructed by the method are aged and can be rehabilitated without dismantling the existing water collection well with reduced strength. It can be suitably used for the purpose of rehabilitating existing drainage wells with reduced strength.

DESCRIPTION OF SYMBOLS 1 Existing drainage well 11 Catchment pipe 12 Attached equipment 2 Rehabilitation pipe 2a Gasket 21 Extension water collection pipe 22 Attached equipment 23 Upper cover 3 Filler 4 Foundation 5 Temporary construction 6 Filler injection plant

Claims (6)

  A rehabilitation pipe installation process in which a synthetic resin rehabilitation pipe is erected with a space inside the existing water collection well, and an extension collection pipe that connects the extension water collection pipe that penetrates the wall of the rehabilitation pipe to the water collection pipe of the existing water collection well. A rehabilitation method for an existing drainage well, comprising a water pipe extension step and a filler placement step for placing a filler in a space between the existing drainage well and the rehabilitation pipe.   The existing drainage well according to claim 1, wherein one existing drainage well is rehabilitated by repeating the rehabilitation pipe installation step, the extended drainage pipe extension step, and the filler placement step as a single cycle. Rehabilitation method.   The rehabilitation method for an existing drainage well according to claim 1 or 2, wherein the rehabilitation pipe is a self-supporting pipe material capable of maintaining its shape.   The method for rehabilitating an existing drainage well according to claim 1, 2, or 3, wherein a through-hole is formed at a position corresponding to the drainage pipe of the existing drainage well on the pipe wall of the rehabilitation pipe.   The rehabilitation pipe installation process, the extended water collection pipe extension process, and the filling material placing process are carried out after regenerating the water collection pipe of the existing water collection well. Rehabilitation method for existing collection wells.   A rehabilitation drainage well constructed by the rehabilitation method for an existing drainage well according to claim 1, 2, 3, 4 or 5.

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