JP2003138611A - Method for constructing water collecting well - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate construction of a water collecting well having a thick filter layer. SOLUTION: According to a method for constructing the water collecting well, a multi-wall well 1 is formed of an outermost wall which is a removable temporary wall 2, and an inner wall 20 having openings 22 for taking in groundwater. Then, a gap between the walls and a center portion of the well are excavated and earth therein is removed, to thereby embed the well under the ground. The number of the openings 22 is set as appropriate and the openings are formed at an altitude corresponding to the location of an aquifer of groundwater when the well 1 is embedded. When the embedding is completed, gravel is charged between the walls to form the filter layer 12. When the outermost temporary wall 2 of the multi-wall well 1 is removed, the thick filter layer 12 is formed on the periphery of the well, and the water collecting well impervious to blocking can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a water collection well that artificially thickens a water permeable layer to increase a water collection area and can stably collect a large amount of good quality groundwater. .

[0002]

2. Description of the Related Art As shown in FIG. 7, the general structure of a water collecting well is that a strainer 1 is provided on the side surface of a well pipe 10 buried in the ground.
1 is formed. The strainer 11 is provided in accordance with the position of the aquifer in the ground, and has a plurality of slits formed in the wall of the well tube 10 in the vertical direction. The gap between the well wall and the ground is filled with gravel that removes impurities that flow into the well pipe 10 together with the groundwater to form the filter layer 12. A mesh made of metal or synthetic resin is provided on the outer peripheral surface of the strainer 11 so that the gravel for the filter does not enter the well pipe 10 through the slit.

In the water collecting well having such a structure, a vertical hole having a diameter larger than that of the well pipe 10 is formed in the ground, and then a strainer 11 is preliminarily formed and a concrete well pipe 10 provided with a wire net is formed in the vertical hole. , And the gap between the well tube 10 and the vertical hole is filled with gravel to form the filter layer 12.

Further, in order to increase the amount of water collected, the diameter of the well has been made large, or the water collecting pipes have been radially extended from the well to increase the water collecting area such as the Manchurian well and the radial well.

[0005]

In the conventional water collecting well, the opening provided in the well wall is in direct contact with the ground, and when the well water is pumped up, impurities such as gravel and dust in the groundwater cause a filter or strainer. The slits of No. 3 were apt to be clogged, so that the water collection capacity tended to decrease, and it was not possible to stably obtain good quality groundwater for a long period of time. The thicker the filter layer is, the more the groundwater that flows into the well will be purified, so if you try to thicken the filter layer, you must increase the diameter of the vertical hole to be drilled.
A large excavating machine is required, the construction period is long, and groundwater is spewing out.
It cost. INDUSTRIAL APPLICABILITY The present invention provides a method for easily forming a thick filter layer around a well wall at low cost, and enables a large amount of groundwater to be efficiently collected for a long period of time.

According to the present invention, a multi-wall well, which is a temporary wall whose outermost wall can be removed, is sunk in the ground, and gravel is filled between the walls to form a filter layer. By removing the outermost temporary wall, a thick filter layer can be formed around the catchment well.

[0006]

[Function] Since the outer wall is a temporary wall with a removable multi-wall well, which is sunk in the ground and filled with gravel between the walls, it is easy to construct a well and fill gravel. It can be easily and accurately performed from the ground, and the filter layer can be formed to have an arbitrary thickness.

[0007]

EXAMPLES Example 1 As shown in FIGS. 1 and 2, a multi-wall well 1 is a concrete cylinder in which multiple cylinders are concentrically arranged.
A blade 4 is formed at the tip. The outermost wall of the multi-wall well 1 is a temporary wall 2, and a concrete panel is detachably fixed to the upper part of the blade of the multi-well well 1. The temporary wall 2 may be made of steel instead of concrete.

The circumferential direction 4 of the wall body 20 inside the multi-wall well 1
An opening 22 is formed at the location according to the position of the aquifer after the deposition. The shape of the opening 22 is an appropriate shape such as a rectangle or a circle, the opening area is larger toward the inner diameter side, and is gentler as the flow velocity of the inflowing groundwater approaches the center of the well. Further, if there is no risk of clogging, a slit may be formed as in the conventional well. The openings 22 are not limited to one stage, and may be arranged in multiple stages in the vertical direction.

As shown in FIG. 3, the multi-wall well 1 is constructed at a construction site of a water collection well, or manufactured at another place is transported and assembled at the construction site. In this embodiment, steel columns (not shown) are erected on the bottom of the multi-wall well 1 at appropriate intervals, and concrete panels are detachably attached between them to form a temporary wall 2. The inner wall 20 is built from the beginning according to the depth of the water collecting well, or as the multiple wall well 1 is sunk, the sunk portion is sequentially built and added. A blade opening 4 is provided at the lower ends of the inner and outer walls to facilitate excavation and discharge of earth and sand in the vicinity of the blade opening 4 to be submerged in the ground.

The space between the temporary wall 2 and the inner wall 20 of the multi-wall well 1 and the central portion of the multi-wall well 1 are excavated by an excavator such as a grab bucket, and the whole multi-wall well 1 is sunk in the ground. If it is difficult to settle with the weight of the Izutsu itself, use a subsidence promoting method such as a press-fitting method using an anchor. In addition, other subsidence-promoting construction methods, such as jetting jets near the cutting edge to reduce the resistance during subsidence, or installing a friction cutter on the upper outer side of the cutting edge to rub the contact surface between the surrounding ground and the outer wall It is also used to supply a friction-reducing material and also to apply a friction-reducing paint to the wall surface that contacts the surrounding ground.

After the multi-wall well 1 is sunk to a predetermined depth, gravel is put between the temporary wall 2 and the inner wall 20 to fill it. Since this gravel becomes the filter layer 12, the temporary wall 2 and the inner wall 20
The interval is designed according to the thickness of the filter layer 12 to be formed. Also, gravel is poured into the bottom of the central portion of the multi-wall well 1 and underwater concrete is poured to form the bottom of the well. When the filling of the gravel is completed, the panels of the temporary wall 2 are pulled out one by one from the ground and removed. Concrete is cast on the aboveground part of the water collection well to cover the gravel, and the central part of the well is covered with a lid to complete.

Example 2 The multi-wall well as shown in FIG. 4 is an example using a triple-wall well. The installation positions of the openings 22 in each wall may be linear as shown in the drawing, or may be arranged so as to be displaced in the circumferential direction. The opening area of the opening 22 is increased toward the inside.

When groundwater is pumped up by a pump or the like through a pumping pipe in a water collecting well constructed by sunk this triple-walled well cylinder into the ground, groundwater passes from the aquifer through the filter layer 12 and through the opening 22. And flows into the inner space of the innermost well wall. Since the opening area of the opening 22 is increased toward the inside, the flow velocity of groundwater passing through each opening 22 becomes gentler toward the inside.

Therefore, since relatively heavy impurities in the groundwater flow are precipitated in the outer space and light impurities are precipitated in the inner space, clean groundwater containing few impurities can be collected. The impurities deposited in the space are appropriately discharged to the ground by a suitable discharging means (not shown) such as an air lift or a pump.

Example 3 In FIG. 5, the inner wall 21 defining the central part of the triple-walled well is not provided with an opening, but a space is formed by pouring underwater concrete on the bottom plate. Groundwater flows into the space between the inner walls 20 and 21, but does not flow into the central portion, so that it can be used as the storage space 5.

Example 4 In the example shown in FIG. 6, an expanded excavation space 6 is formed at the bottom of a multi-wall well 1 and a cutting edge 4 is provided at the tip of the excavation space 6. A removable temporary wall 2 is provided on the outermost side where the diameter is expanded, as in the above-described embodiment, and a plurality of openings 22 are formed in the wall body 20 of the multi-wall well 1.
Excavating the excavation space 6 of this multi-wall well 1
Is sunk in the ground. Excavation near the cutting edge 4 is performed using an excavator with an extending arm. Further, it is also possible to install a lid 7 so as to close the excavation space 6 as needed and perform excavation as an air caisson.

When the multi-wall well 1 is completely sunk, the wall 20
The gravel is charged and filled between the wall and the temporary wall 2, and the temporary wall is removed, and the wall 2
The filter layer 12 is formed on the outside of 0.

[0018]

EFFECTS OF THE INVENTION The present invention in which multiple wells having a removable temporary wall on the outermost side is sunk in the ground to form a water collecting well is simpler than the conventional method of excavating a vertical hole, and the inner wall The space between the temporary walls can be freely determined, and construction can be done in a short period of time even if the filter layer is thickened.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view of a water collection well using a multi-wall well.

FIG. 2 is a plan cross-sectional view of a water collection well using a multi-wall well.

[Fig. 3] Construction drawing of the collection well.

FIG. 4 is a partially cutaway front view of a triple well multi-well.

FIG. 5 is a front cross-sectional view of a water collection well having a central portion as a storage space.

FIG. 6 is an example of another multi-wall well.

FIG. 7 is a sectional view of a conventional water collecting well.

[Explanation of symbols]

1 Multi-walled Izutsu 2 Temporary wall 12 filter layers 20, 21 inner wall 22 opening 4 blade

Claims (2)

[Claims] 1. A multi-wall well, which is a temporary wall whose outermost wall can be removed, is sunk in the ground, gravel is filled between the walls to form a filter layer, and the outermost temporary wall is removed. How to construct a catchment well. 2. The method for constructing a water collection well according to claim 1, wherein the outermost temporary wall is formed by connecting plate members.