JPH0696845B2 - Deep well installation method and strainer device used for this - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a deep well installation method for pumping groundwater from the ground to lower the groundwater level or improve the ground, and a strainer device used therefor.

<Prior Art> When constructing a structure, a groundwater level lowering method is often adopted in order to increase the strength of the foundation ground and ensure stability or workability during excavation. There are various methods for this method, one of which is a deep well installation method in which the ground is drilled and a strainer (water collection pipe) is installed in the hole.

The conventional deep well installation method is outlined.There are methods using a Benot excavator, a method using a boring machine, a method using an earth auger, etc. as the drilling method, and the method using the Benot excavator is the most reliable method. There is. With this method, the casing tube is pressed into the ground while rocking, the inside of the casing tube is excavated by a grab hammer, and when the excavation depth reaches a predetermined level, a strainer with a water passage hole (slit) is inserted. ,
Then, the casing tube is pulled out while the filter material is packed between the strainer and the casing tube, and the deep well is installed.

In such a conventional deep well installation method, it is necessary to alternately perform the operation of press-fitting / adding the casing tube while excavating with a grab hammer, which takes time and labor, and the efficiency of excavation work is significantly deteriorated. And the cost of equipment becomes high.

On the other hand, the Applicant first performed a simple work in a short time,
Moreover, we have applied for a deep well installation method that enables reliable and economical installation of deep wells with a diameter of 30 to 60 cm.

This is a casing tube containing a strainer, which is locked at the tip of an opening-and-closing type shoe, is driven to a predetermined depth by a driving device, and the filter material is put between the strainer and the casing tube, and the casing tube is grounded. The strainer is pulled out and left in the ground.

<Problems to be Solved by the Invention> However, in such a conventional deep well installation method, when the casing tube is pulled out or when the ground is subsided, a part of the filter material is biased near the outer circumference of the strainer or is unevenly divided into upper and lower parts. As a result, there is a problem that the fine-grained soil directly enters the strainer, and the fine-grained soil is clogged at the above-mentioned divided site.

The present invention has been made in view of the above problems, and an object thereof is to prevent the filter material from being biased near the outer periphery of the strainer when the filter material is charged, and at the time of pulling out the casing tube or the ground. (EN) It is intended to provide a deep well installation method that prevents uneven distribution and division of a filter material that is put in at the time of subsidence.

Another object of the present invention is to provide a strainer device which prevents the filter material from being biased at the time of charging and unevenly distributed after being charged, and restrains the charged filter material to the outer periphery of the strainer with a constant thickness.

<Means for Solving the Problems> The gist of the deep well facility construction method according to the present invention is to use a strainer equipped with a water-permeable bag with a predetermined gap on the outer periphery, and insert a casing tube containing the strainer therein. A step of driving to a predetermined depth of the ground by a device, and a step of charging a filter material between the strainer and the bag in parallel with the driving step or after the driving step,
A deep well installation method comprising a step of pulling out the casing tube in parallel with the charging step or after the charging step.

Further, the gist of the strainer device of the present invention is, in a strainer provided with a lid on an upper portion for installing a deep well to be installed in a casing tube penetrating into the ground, the strainer is
A mounting member protruding from the upper and lower ends of the strainer with a gap for introducing the filter material, and a mounting member installed between these upper and lower attachment members to maintain a constant gap with the strainer for introducing the filter material, and the casing tube Is a strainer device consisting of a water-permeable bag for introducing the filter material, which is placed at a distance such that the introduced filter material does not enter.

<Operation> The water-permeable bag according to the present invention is installed in the casing tube together with the strainer when the casing tube is driven into the ground, and the filter material is put between the strainer and the bag with the casing tube being driven. Then, when the casing tube is pulled out, the bag wraps the filter material from the outside and is left in the ground together with the strainer. Therefore, this bag acts to restrain the filter material and prevent the filter material from being divided or unevenly distributed.

Further, in another invention of the present invention, the mounting member forms a gap between the strainer and the bag so that the filter material can be reliably put therein, and the bag is provided between the strainer and the casing tube. Since the filter is installed at a distance that does not allow the filter to enter, the filter material is surely put between the strainer and the bag.

<Embodiment of the Invention> An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a process diagram of a deep well installation method according to the present invention, and FIG. 2 is a configuration diagram of a sand drain driving machine as a driving device used in this method. In the figure, 1 is a caterpillar wheel, 2 is a leader standing on the caterpillar wheel, 3 is a wire rope suspended above the leader 2, and a vibro hammer is hung at one end thereof via a shock absorber 8. 5 is a hopper connected to the vibro hammer 4; 6 is a bucket for moving the gravel as a filter material while moving up and down along the leader 2; 7 is a casing tube connected to the lower part of the hopper 5; A strainer 12 such as a flexible tube is inserted.
The strainer 12 has an elongated cylindrical shape, and the upper and lower ends of the strainer 12 have six frames radially protruding from the center.
22 and a fixing metal fitting 14 consisting of a circular bag mounting ring 23 slightly smaller than the inner diameter of the casing tube 7 are installed on the outer circumference of the frame 22, and the outer circumference of the strainer at the upper and lower ends of the fixing metal fitting 14 and the bag. Suspending ropes 26 each having six spacers 27 attached are arranged between the rope attaching ribs 25 interposed between the attaching rings, and these fixing brackets 14 and the suspending ropes 26 are formed into a tubular shape with a water-permeable bag 18. It consists of a cover. Further, in FIG. 1, 9 is the wire rope 3
, 10 is another pulley for supporting the suspended wire rope 11 put in the casing tube 7 from the lower part of the hopper 5, 12 is a water-permeable pipe strainer such as a flexible pipe, 13 is a filter material, 14 Is strainer 12
, 15 is a submersible pump, 16 is a pumping pipe, 17 is a sling (bottom lid) hinged to the lower end of the casing tube 7 so that it can be opened and closed, and 18 is a water-permeable material attached to the outer circumference of the strainer 12. The bag 18 is a tubular bag, and the bag 18 is made of a high-strength member such as polypropylene.

FIG. 3 shows the strainer 12 in the casing tube 7.
FIG. 3 is a partially cutaway perspective view showing an essential part of the attachment structure of the bag 18 and the bag 18, in which reference numeral 14 is a fixing metal fitting as an attachment member attached to the upper end of the strainer 12, which is a filter material that is inserted from above The strainer 13 includes a lid 21 for preventing the strainer 13 from entering the strainer 12, a plurality of rope attachment frames 22, and a bag attachment ring 23. Reference numeral 24 is a fixing metal fitting as a mounting member for the bag 18 attached to the lower end of the strainer 12, and constitutes a strainer device together with the strainer 12, the fixing metal fitting 14 and the bag 18. These upper and lower fixing brackets 14
The water-permeable bag 18 provided between the outer wall of the strainer 12 and the outer wall of the strainer 12 is made slightly smaller than the diameter (inner diameter) of the casing tube 7 so that the filter material 13 does not enter. A sufficient gap is provided for receiving and restraining the filter material 13 that is used. Reference numeral 25 denotes a plurality of rope mounting ribs provided on the upper part of the periphery of the fixing metal fitting 24. These ropes are connected to the plurality of rope mounting frames 22 by a hanging rope 26 so that the load of the strainer 12 or the like is fixed to the fixing metal fitting 24 and the hanging rope 26. The wire rope 11 is supported through the fixing metal fittings 14 in sequence. 27 is a plurality of spacers, strainer 12
On the outer peripheral surface of the bag, for example, the bag 18 is vertically projected at intervals of 1 m.
The gap between the strainer and the outer circumference of the strainer 12 is kept uniform in each part.

Further, FIG. 4 is an explanatory diagram showing a filter material charging state in such an attachment structure.

Next, the steps of installing a deep well will be sequentially described with reference to FIGS. 1 and 4.

First, using the sand drain driving machine, the casing tube 7 is installed in the deep well installation location as shown in FIG. 1 (a). That is, the casing tube 7 is lifted by the wire rope 3 to a predetermined height. Next, open the shoe 17 to which the hanging wire rope 11 suspended in the suspended casing tube 7 is hinged, is taken out from the lower end of the casing tube 7, and the lower end thereof is shown in FIG. 1 (b). As shown in FIG. 5, the bag 18 is locked to the fixing metal fitting 14 at the upper end of the water-permeable strainer 12. Here, the hanging wire rope 11 is wound up by a winch or the like via the pulley 10, and the strainer 12 is pulled up to a predetermined height as shown in FIG. 1 (c). At this time, the lower end of the strainer 12 is the casing tube 7
Make sure that it fits inside, and then close the boom 17. This state is shown in FIGS. 3 and 4 (a).

Then, the wire rope 3 is loosened, and the casing tube 7 and the strainer 12 are lowered to the ground as shown in FIG. 1 (d). Here, the casing tube 7 is sequentially penetrated to a predetermined depth in the ground by the vibro hammer 4 in the driving device, as shown in FIGS. 1 (e) and 1 (f). When the final depth is reached, first, the filter material 13 is placed between the strainer 12 and the bag 18 as shown in Figs. 4 (b) and (c).
Then, the casing tube 7 is pulled out. If necessary, the filter material 13 is charged even while the casing tube 7 is being pulled out. The above bag
Putting the filter material 13 into the space between the strainer 18 and the strainer 12,
As shown in FIG. 1 (e), it may be performed in parallel with the penetration of the casing tube 7. Next, when the casing tube 7 is pulled out by about 1 m with the vibro hammer 4, the shoe 17 locked at the tip opens the open end of the strainer 12 due to the friction with the soil, and the strainer 12 and the bag 18 inside are thrown in. It stays in the ground with the filter material 13 to be removed. The supply of the filter material 13 can be easily performed by moving it from the bucket 6 guided by the leader 2 to the hopper 5 below the vibro hammer 4.

In this way, by inserting the filter material 13 and pulling out the casing tube 7, as shown in FIG.
As shown in, the strainer 12 contained in the casing tube 7 is left in the ground together with the bag 18 that wraps the filter material 13 from the outside. At this time, the high pressure air is discharged from the head of the casing tube 7 toward the inside thereof, so that the filter material 13 can be smoothly pushed out into the ground.

Next, after removing the fixing brackets 14 attached to the strainer head, if the submersible pump 15 is installed in the lower part of the strainer 12 as shown in FIG. 1 (h), groundwater will be discharged to the ground through the pipe 16. it can. That is, by using this strainer 12 as a deep well and forcibly pumping water by the pump, the groundwater level can be lowered.

In this way, when the bag 18 that wraps the filter material 13 from the outside is left in the ground, the casing tube 7
Despite the above-mentioned pulling out, since the filter material 13 is constrained by the bag 18, it is partially biased
The outer peripheral portion of the strainer 12 is not divided in the vertical direction, a uniform thickness can be secured over the entire length of the outer peripheral portion of the strainer 12, and clogging of fine soil can be effectively prevented.

The strainer 12 may use a steel pipe or a hard vinyl chloride pipe, but if a commercially available flexible water collection pipe is used, it can be easily inserted into the casing tube 7 even if it is long and there is no fear of corrosion. .

The deep well can be installed very quickly and easily by simultaneously inserting the casing tube 7 and the strainer 12 covered with the bag 18 into the ground and inserting the filter material 13 in parallel therewith. Can be shortened.

If the casing tube 7 is driven in while ejecting high-pressure water or air from the lower end of a pipe (not shown) along the casing tube 7, a deep well can be installed without vibration and noise. .

<Effects of the Invention> As described above, the deep well installation method of the present invention uses a strainer in which a water-permeable bag is attached with a predetermined gap on the outer periphery, and this strainer is grounded by a driving device together with a casing tube in the ground. Since the filter material was put into the bag during or after the driving, the filter material is restrained inside the bag on the outside of the strainer, so that even if the casing tube is pulled out or the frictional force due to ground subsidence is received. It is possible to prevent the strainer from being clogged by the fine-grained soil from the ground, without biasing the filter material partly or dividing it vertically.

Further, the strainer device of the present invention has a lid on its upper part,
In order to put the filter material between the mounting members projecting at the upper and lower ends of the outer circumference, a constant gap is maintained between the strainer and By installing the water-permeable bag, the filter material can be evenly and easily put into the gap between the strainer and the bag, and the entire bag can be stably supported by the strainer.

[Brief description of drawings]

1 (a) to 1 (h) are operation explanatory views showing a deep well installation method according to the present invention, FIG. 2 is a schematic configuration diagram of a sand drain driving machine, and FIG. 3 is a strainer device according to the present invention. Partially broken perspective views and FIGS. 4 (a) to 4 (c) are also explanatory views showing the feeding state of the filter material. 4 ... Driving device, 7 ... Casing tube, 12 ...
Strainer, 13 ... filter material, 14, 24 ... fixing bracket (mounting member), 18 ... bag.

Claims (2)

[Claims] 1. A step of using a strainer having a water-permeable bag attached with a predetermined gap on the outer periphery, and driving a casing tube containing the strainer to a predetermined depth of the ground by a driving device, and the driving step. In parallel with or after the driving step, charging the filter material between the strainer and the bag, and pulling out the casing tube in parallel with the charging step or after the charging step. Installation method. 2. A strainer device for installing a deep well, which is installed in a casing tube penetrating into the ground, wherein the strainer device comprises a strainer loaded in the casing tube and a filter material introduced from above into the strainer. It has a lid that keeps it from entering, and mounting members that project from the strainer to the upper and lower ends of the strainer with a gap for inserting the filter material into the strainer, and insert the filter material that is fixedly mounted between these upper and lower mounting members. A strainer device for maintaining a constant gap with the strainer, and a water-permeable bag for introducing a filter material with a distance that the inserted filter material does not enter the casing tube. .