JP2000265452A - Permeability improvement method for ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sufficient and wide permeability in the periphery of a water intake well without affecting to a shape and a size, etc., of the intake well installed in the ground. SOLUTION: When a force feed path 30 for mixing pressurized liquid W and gas A to gush to the outside is penetrated into ground G to move according to a predetermined permeability improving area R, the ground G is stirred to loose. Heavy particles of soil particles which compose the ground G are precipitated, and light particles of the soil particles are blown off to the outside of the improving area R and are floated up by bubbles B generated from the liquid W and the pressurized gas A. Thereby, fine soil particles are removed from the permeability improving area R, and the improving area R is mainly composed of coarse-grained soil particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the water permeability of the ground, and more particularly to a technique for improving the water permeability around an intake well installed in the ground.

[0002]

2. Description of the Related Art In order to properly maintain and operate structures by appropriately draining around buildings, buildings, roads, various structures such as railways, etc., and to improve the working environment during civil engineering or construction work. 2. Description of the Related Art An operation of collecting groundwater in the ground for various purposes, for example, or simply for supplying various types of water, is performed.

[0003] At this time, in general, a drain method for forming an intake well by laminating a soil material or the like having good water permeability in the ground in a column shape, or drilling the ground to a predetermined depth to form a drilled hole. A deep well method or the like in which a pipe having a water hole or the like is inserted therein to form an intake well and a drain pump or the like is inserted into the intake well to take water is applied to the intake work.

[0004] However, when the water intake is continued for a long time by the above-mentioned water intake method, fine soil particles contained in the ground and various foreign substances in the groundwater are not allowed to pass through the gap between the soil material in the intake well and the pipe. Water permeability deteriorates by entering water holes, etc., and eventually filling and closing the gaps and water holes, etc., and also filling and closing the gaps in the surrounding ground itself where water is being taken. There was a problem. If such a problem occurs, it is unavoidable that the water intake efficiency will be remarkably reduced, and it will be difficult to secure the initially assumed water intake amount.

Therefore, conventionally, a nozzle or the like for injecting compressed air or high-pressure water is inserted into an intake well, and the ground around the intake well is compressed by compressed air or high-pressure water ejected from a water hole or the like provided in the intake well. The water permeability has been improved by using a method such as wiping fine soil particles.

[0006]

However, the conventional method for improving water permeability has the following problems.
In other words, in order to inject compressed air or high-pressure water from the inside of the intake well to the surrounding ground, it is necessary to pump air or water at a considerably high pressure. Even if it is injected, the effect of compressed air or high-pressure water only affects a very limited area around the intake well after all.
Therefore, it is difficult to sufficiently remove the fine soil particles that clog the gaps in the ground. In addition, if the void space around the intake well is a mixed state of a clogged part already filled with fine soil particles and a water-permeable part that can pass water, compressed air or Even if high-pressure water is injected, these fluids pass through the water-permeable portion, which is easier to flow, and do not easily lead to clearing out fine soil particles in the clogged portion.

Further, for example, when the inside diameter of the intake well is large, compressed air or high-pressure water or the like to which excessive pressure is applied is pumped to the intake well, and the intake well responds to the pressure. If there is a problem with proof stress such as whether it is structurally durable, or even if it is durable, if the pumping cannot be performed with sufficient pressure, the range of jetting compressed air or high-pressure water is more limited than usual. There is a problem that the water content is limited to the range and a sufficient improvement in water permeability cannot be expected.

Accordingly, the present invention has been made in view of such conventional problems, and is not affected by the shape and size of the intake well installed in the ground, and has a sufficient and wide area around the intake well. It is an object of the present invention to provide a method for improving the water permeability of the ground, which makes it possible to improve the water permeability.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and a pressure feed path for mixing a pressurized liquid and a gas and ejecting the mixture to the outside is provided with a predetermined water permeability. The ground is agitated and loosened by penetrating and moving the ground according to the range, heavy particles among the soil particles constituting the ground are settled, light particles are blown out of the improvement range, and the liquid and the pressurized gas are blown out. By floating with bubbles generated from, remove fine soil particles from the permeability improvement range,
The improvement range is mainly characterized by coarse soil particles.

[0010]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an explanatory view showing an embodiment to which the method for improving soil permeability of the present invention is applied.

In this embodiment, a situation is described in which an intake pipe P is buried as an intake well below the underwater floor of, for example, the sea 10 or a river or lake, and as shown in FIG. A case will be described in which a work boat 20 which is a work subject when implementing the improvement method is arranged and the improvement work is performed.

The water intake pipe P is provided for, for example, various power generation facilities and deep water sampling facilities for securing cooling water and for intake purposes, or simply for drainage purposes. A plurality of water intake holes (not shown) having a predetermined shape are provided on a peripheral surface of the steel pipe or the concrete pipe or the like, which penetrate the pipe wall and communicate the inner space and the outside of the pipe through filters. ing. Groundwater outside the pipe flows into the pipe through this water intake hole, and water is collected.

When water is taken by using the intake pipe P for a long period of time as described above, it rides on the flow of groundwater flowing into the intake pipe P, and the fine particles contained in the ground G around the intake pipe P and in the groundwater. Soil particles, foreign matter, algae, microorganisms such as bacteria and plankton, etc. are naturally drawn to the vicinity of the intake hole, and gradually fill the hollow G of the ground G around the intake pipe P around the intake hole. Will be done. When such a situation is reached, the flow of the groundwater toward the intake pipe P is obstructed, and a drastic decrease in the intake amount and the intake efficiency is unavoidable. As a result, other voids in the remaining ground G also serve as the flow path of the groundwater, and are gradually closed by fine soil particles and the like, and the ground G around the intake pipe P is in a state where the voids are closed to a considerable extent. There is a risk.

Therefore, as shown in FIG. 2, for example, compressed air A and high-pressure water W are respectively fed under pressure in the pipe, and the two are mixed near the injection nozzle 32 at the lower end of the pipe. The water permeability is improved by using a multiple pipe rod 30 that is jetted from the tip 32. The multi-tube rod 30 is made of, for example, steel and has strength enough to withstand various stresses generated during the water permeability improvement work, and has a joint portion at an end portion so that it can be appropriately added according to work conditions such as an improvement range and a depth. It has. The swivel part 31 shown in FIG. 3A is rotatable by forming the upper end of the multiple pipe rod 30, and includes a high-pressure water pressure transmission path 30a and a compressed air pressure transmission path 30b.
(B) shows the lower end of the multi-tube rod 30, and the high-pressure water A and the compressed air W, which have been pressure-fed in the multi-tube rod 30, are injected into the injection nozzle 32 provided at the lower end of the multi-tube rod 30.
This is injected as a mixed flow M. At the tip of the lower end of the rod 30, a drilling nozzle 34 is provided for performing drilling work by spraying drilling water when the rod penetrates into the ground, and on both sides thereof, for disturbing the ground around the rod. The blade bit 34a is mounted. When the high-pressure water W and the compressed air A from the drilling nozzle 34 do not need to be jetted out at the lower end of the high-pressure water pressure transmission path 30a (such as after the rod has penetrated the ground).
And a check valve 33 for preventing inflow of groundwater are attached.

In the actual water permeability improving operation, first, the work boat 20 is moved to the vicinity of the improvement target area R and the penetrating device 21 is activated. The work boat 2 is passed through the pumping pipe 22 to the multiple pipe rod 30 mounted on the activated penetrating device 21.
The compressed air A and the high-pressure water W are supplied from the pressure pump 23 inside the cylinder. After the operation of each device, the multiple pipe rod 30 is lowered through the water from above the ship toward the ground G to be improved in water permeability, and the multiple pipe rod 30 is moved to the vicinity of the intake pipe P in the ground G as shown in FIG. 30 is penetrated. During this penetration, drilling water is sprayed from a drilling nozzle 34 at the tip of the rod 30, and the blade-like bits 34a provided on both sides of the rod 30 are rotated to disturb the ground around the rod to perform a drilling operation. When drilling is completed, a steel ball 33a
To prevent the high-pressure water W and the compressed air A from squirting and leaking.

After the rod 30 has penetrated, a mixed flow M of the compressed air A and the high-pressure water W is supplied from the injection nozzle 32 provided at the side of the lower end of the rod 30 to the outer ground G at a predetermined pressure and injection amount. , And at the same time, the ground G is stirred upward while rotating the rod 30 itself.

By this stirring operation, fine soil particles and various fine foreign substances in the ground G are blown off in the jetting direction, and at the same time, ride on the upward flow of the high-pressure water W contained in the jetted mixed flow M. The ground G.
At that time, the bubbles B generated from the compressed air A are included in the upward flow of the high-pressure water W, and the flow of the rising water flow is made smoother, and the floating of the fine soil particles and the like is assisted and promoted. Also,
By adhering and rising to the surface of the bubble B, fine soil particles and the like may be floated. In addition, fine soil particles and the like are also removed to the outside by being blown off using a void existing in the ground as a passage. On the other hand, the heavy and coarse particles are settled below the stirred ground G without being blown away far. In other words, if the method for improving soil permeability of the present invention is applied, the ground G to be improved is agitated by the high-pressure water W and the compressed air A, and the ground G around the intake pipe P is mainly composed of coarse particles. The ground G is reconstructed. Therefore, fine soil particles that are contained in the ground G and fill the gaps in the ground G and stagnate the groundwater flow are substantially removed from the improvement range R.

In the present embodiment, an example in which the present invention is applied to the ground G around the intake pipe P buried in the water is shown. However, the present invention is not limited to this, and any type installed in any area of sea and land can be used. Can be applied under any conditions as long as it can be injected with the high-pressure water W and the compressed air A. Further, depending on the situation, it is of course applicable to improve the permeability of the ground where there is no intake well. In addition, the present invention can be applied to, for example, a clogging phenomenon of the ground due to a foreign substance or the like contained in drained water around a drain well having a similar structure instead of an intake well.

[0019]

As described in detail above, the method for improving the water permeability of the ground according to the present invention provides a pressure feed path for mixing a gas and a pressurized liquid such as compressed air or high-pressure water and jetting the mixture outward. To
The ground is agitated and loosened by penetrating and moving the ground in accordance with a predetermined permeability improvement range, heavy particles among the soil particles constituting the ground are settled, and light particles are blown outward and the liquid is mixed with the liquid. By floating with air bubbles generated from the pressurized gas, fine soil particles are removed from the water permeability improvement range, and the improvement range is mainly made of coarse soil particles. Injecting compressed air and high-pressure water arbitrarily if it is not only a limited area near the intake well as in the method of jetting compressed air or high-pressure water from the inside of the well, but also if the permeability improvement range where improvement is required It is possible to have an improving effect, so that the fine soil particles clogging the gaps in the ground can be sufficiently removed over a wide range.

In addition, the method for improving the water permeability of the ground of the present invention performs the water permeability improvement work not on the inside of the intake well but on the outside. Therefore, the method is completely affected by the shape and size of the intake well installed in the ground. Without this, it is possible to sufficiently and widely improve the water permeability around the intake well.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment to which a method for improving soil water permeability according to the present invention is applied.

FIG. 2A is a cross-sectional view of a swivel portion at an upper end of a pressure feeding path, and FIG. 2B is a cross-sectional view of an injection nozzle at a lower end of the pressure feeding path.

[Explanation of symbols]

 A Pressurized gas, compressed air W Pressurized liquid, high-pressure water B Bubble G Ground R Permeability improvement range 30 Pressure feed path, multiple pipe rod

Claims (1)

[Claims] 1. The ground is agitated and loosened by penetrating and moving a pressurized feed path, which mixes a pressurized liquid and a gas and jets outward to a ground according to a predetermined range of water permeability improvement. Heavy particles among the soil particles constituting the ground are settled, and light particles are blown out of the improvement range and floated by bubbles generated from the liquid and the pressurized gas. And improving the range of the soil from mainly coarse-grained soil particles.