JPH0313369B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is useful, for example, in preventing ground subsidence caused by the release of groundwater from underground during excavation for underground construction work, etc., and in reducing the amount of groundwater released into sewers, etc. This is a method that is employed when returning groundwater to the ground in order to reduce the amount of groundwater, and more specifically, it relates to a method of supplying ground subsidence water into the ground through a vertical hole formed in the ground.

For example, the conventional water supply method for ground subsidence prevention, which is used to restore groundwater to prevent ground subsidence caused by the release of groundwater from underground during excavation, is as shown in Figure 2. - A casing 3 and a strainer 2 that form the groundwater return vertical hole 1 are formed in a vertical hole larger than the groundwater return vertical hole 1 (for ground subsidence prevention water supply) by earth drilling etc. At the same time, a water-permeable layer 15 is formed on the outer periphery of the strainer 2 by backfilling with pea gravel, etc., and the upper part of this water-permeable layer 15 is closed with a packer seal 16 (clay, etc.). The outer peripheral part of the upper casing 3 is backfilled with earth and sand 17, and groundwater from the excavation work area A is supplied into the casing 3, that is, into the vertical hole 1, and the head pressure of the supplied groundwater in the vertical hole 1 Supplying groundwater to the vertical hole 1 periodically or irregularly while discharging the supplied groundwater into the ground through the strainer 2 and the permeable layer 15,
In other words, water in the vertical hole 1 is discharged to the outside through the submersible pump 18, pipe 19, etc. while the return of groundwater to the underground is stopped, and the water is pumped from underground through the permeable layer 15 and the strainer 2 into the vertical hole. In this method, by suctioning the strainer 2 into the strainer 1, dirt and other clogs in the groundwater that have become clogged in the strainer 2 as the groundwater returns to the ground are removed and discharged to the outside together with the water. In addition, 20 in FIG. 2 is a tank for precipitating and separating earth and sand in groundwater.

However, when using this conventional method, in order to form a vertical hole for groundwater return, it is necessary to excavate a vertical hole that is larger than the vertical hole for groundwater return, which requires a large amount of excavation. It takes a lot of effort and time, and the cost of processing excavated soil increases.
In addition, secondary work such as installing patch seals and backfilling with earth and sand is required, and overall, the workability of forming vertical holes for groundwater return is very poor, and creating vertical holes for groundwater return requires a large amount of cost. There are some drawbacks. Moreover, since the groundwater is returned to the ground by the head pressure of the groundwater supplied into the vertical hole, the force of pushing the groundwater into the ground is weak, and it takes a long time to return the groundwater. It takes a long time to reliably remove the clogged material in the strainer by suctioning water into the vertical hole, and the overall efficiency of reducing groundwater is extremely poor.

In view of these conventional drawbacks, the present invention seeks to provide a method that allows vertical holes for supplying ground subsidence prevention water to be formed with good workability and at low cost, and that allows ground subsidence prevention water to be efficiently returned to the ground. Have a purpose in mind.

The feature of the underground prevention water supply method according to the present invention, which was taken to achieve the above object, is that the casing for forming a vertical hole is slightly pulled out, a strainer having the same diameter or almost the same diameter as the casing is provided at the site where the casing has been pulled out, and By pressurizing the inside of the vertical hole with the upper part of the vertical hole in the casing closed and supplying the water into the vertical hole against this pressurizing force, the water is forced into the ground through the strainer and released. a mechanism that automatically and reversibly communicates the inside of the vertical hole with the outside when the pressure inside the vertical hole exceeds a certain level; and a mechanism that scrapes clogging by rubbing the inner surface of the strainer. The present invention is implemented by providing a mechanism for removing and discharging scraped materials to the outside, and the functions of the present invention having such characteristics are as follows.

In other words, the excavation work to form vertical holes for water supply to prevent ground subsidence only needs to be excavated inside the casing, so the amount of excavation is small, the labor and time spent on excavation can be reduced, and the processing required during excavation can be reduced. Costs can be reduced. ○ After excavation, the construction of the vertical hole for water supply to prevent ground subsidence can be completed by simply installing a strainer, which improves the ease of construction of the vertical hole for water supply to prevent ground subsidence. ○The inside of the casing (vertical hole) is pressurized and the water supplied into the vertical hole is forced into the ground through a strainer and released into the ground, increasing the speed of water supply into the ground and efficiently pumping water underground. can be supplied to ○D When the pressure inside the vertical hole exceeds a certain level due to the strainer being clogged with earth and sand due to the supply of water such as groundwater, a safety mechanism is activated and the inside of the vertical hole is opened to the outside. Since the pressure inside the vertical hole is communicated with the outside and the pressure inside the vertical hole is released to the outside, it is possible to prevent failure and damage to the water pressurization supply mechanism due to overload, and the safety mechanism such as the pressure inside the vertical hole is released to the outside. You can tell that the strainer is clogged by the operation. ○E Based on the operation of the safety mechanism, etc., the clogging removal mechanism is operated with the water pressurization supply mechanism stopped, thereby quickly and reliably removing the clogging substances adhering to the strainer. Since the strainer can be discharged outside, the strainer can always be kept free of clogging, allowing water to pass through the strainer and, in other words, to be supplied underground. At the same time, the interruption time of water supply for removing clogging of the strainer can be extremely shortened.

Therefore, the present invention makes it possible to form vertical holes for supplying water to prevent ground subsidence with good workability and at low cost, and also to efficiently supply water underground through the vertical holes. As a whole, it has been possible to achieve the effect that water for preventing ground subsidence can be supplied underground very economically.

Embodiments of the present invention will be described below based on the drawings.

1 is a vertical hole formed outside and near the excavation work area A reaching below the impermeable layer B, and 2 is a vertical hole formed by pulling out the excavation forming casing 3 of this vertical hole 1. This is a vinyl chloride strainer built in the area where the casing was pulled out.
The upper part of the vertical hole 1 is closed with a lid 1a.

4 pressurizes the inside of the vertical hole 1 and supplies groundwater sent from the deep well a of the excavation work area A via the pipe 5 into the vertical hole 1 against the pressurizing force. This is a mechanism for pressurizing and releasing groundwater into the ground through the strainer 2, which includes a compressor 4A that pressurizes air into the vertical hole 1, and a compressor 4A that stores groundwater from the deep well a and precipitates earth and sand. Sand settling tank 4B
and a submersible pump 4D that presses and supplies the groundwater in the sand settling tank 4B into the vertical hole 1 through a pipe 4C against the pressurizing force.

6 is a safety mechanism that automatically and reversibly communicates the inside of the vertical hole 1 with the outside when the pressurizing force inside the vertical hole 1 exceeds a certain level;
and a sensor 8 that detects when the pressurizing force inside the vertical hole 1 exceeds a certain level, and a sensor 8 that is installed in the outside of the vertical hole 1 of the discharge pipe 7 and opens based on the detection by the sensor 8. It is composed of a solenoid valve 9.

Reference numeral 10 denotes a mechanism that scrapes off clogging materials such as dirt and sand by sliding the inner surface of the strainer 2 and discharges the scraped materials to the outside. a strainer cleaning brush 12; a winch 13 that winds up the universal hose 11 and slides the brush 12 upward;
a weight 14 that slides the brush 12 downward as the universal hose 11 is fed out;
It consists of a pump 15 that sucks out water and scraped material from the strainer 2 through the universal hose 11.

Next, the work procedure after installing the strainer 2 will be explained.

By activating the groundwater pressurized supply mechanism 4 and pressurizing and supplying groundwater into the vertical hole 1, the groundwater is pressurized and discharged into the ground through the strainer 2.

As a result of the above, the strainer 2 becomes clogged, and as a result, the pressure inside the vertical hole 1 becomes higher than a certain level, and the safety mechanism 6 is activated, and the water inside the vertical hole 1 is discharged through the discharge pipe 7. When a certain amount or more has been discharged, the brush 12 of the clogging removal mechanism 10 is activated, and the pump 15 is activated to remove the clogging from the strainer 2 and discharge it to the outside together with water. Complete the clog removal.

According to the above embodiment, there are advantages as listed below.

[1] Since only the inside of the casing 3 needs to be excavated, the amount of excavation can be reduced, the labor and time required for excavation can be reduced, and the processing cost of excavated soil can be reduced.

[2] Since the inside of the casing 3 is pressurized and the groundwater is forced into the ground and released, the amount of groundwater released per unit time can be increased considering the size of the vertical hole 1.

[3] Since the safety mechanism 6 prevents the pressure inside the vertical hole 1 from exceeding a certain level due to clogging of the strainer 2, the pump 4D and the piping 4C in the groundwater pressurization supply mechanism 4 Failure and damage due to overload can be prevented, and clogging of the strainer 2 can be detected by draining water.

[4] Since the clogging removal mechanism 10 can quickly and reliably remove the clogging of the strainer 2, it is possible to remove the clogging of the strainer 2 regularly or irregularly. Good discharge of groundwater into the ground through strainer 2.
And it can be done reliably.

[5] Since the strainer 2 is made of vinyl chloride, which does not rust, which is one of the causes of clogging, clogging of the strainer 2 can be suppressed.

[6] There is no need to stop the supply mechanism 4 when removing clogging.

In the above embodiment, the vertical hole 1 is closed by press-fitting air.
Although the inside of the vertical hole 1 is pressurized, the inside of the vertical hole 1 may be pressurized by supplying ground water under pressure.

In addition, examples of water for preventing ground subsidence include not only groundwater from the excavation work area but also various types of wastewater such as factory wastewater, city tap water, river water, and the like.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment, and FIG. 2 is a longitudinal sectional view showing a conventional example. 1...Vertical hole, 3...Casing, 2...Strainer, 4...Water pressurization supply mechanism, 6...Safety mechanism,
10... Clogging removal mechanism.

Claims (1)

[Claims] 1 A method of supplying ground subsidence water into the ground through a vertical hole 1 formed in the soil, in which the casing 3 for forming the vertical hole is slightly pulled out, and the casing 3
A strainer 2 having the same diameter or approximately the same diameter as the casing 3 is provided at the extraction site, and the inside of the vertical hole 1 is pressurized while the upper part of the vertical hole 1 in the casing 3 is closed, and the strainer 2 is applied against this pressurizing force. A mechanism 4 for pressurizing and releasing water into the ground through a strainer 2 by supplying the water into the vertical hole 1, and a mechanism 4 that automatically and Mechanism 6 for reversibly communicating the inside of the vertical hole 1 with the outside
By rubbing the inner surface of the strainer 2,
A water supply method for preventing ground subsidence, which is implemented by providing a mechanism 10 for scraping off clogging materials and discharging the scraped materials to the outside.