JPH09151686A - Borehole packing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain packing even in a place having no ground water and even in a place which requires precise chemical analysis while the advantage of a packer material made of hygroscopic swelling high polymer material is used usefully and to be enough good for a long time use. SOLUTION: A cylindrical member 12 is inserted in the inside of a bored hole 10 formed in the ground, and a gap between the cylindrical member 12 and the hole wall is packed with a packer material 14. Previously the packing part of the cylindrical member is surrounded with the packer material 14 made of hygroscopic swelling high polymer material, a rubber tube 16 is put on the outside thereof, bot end parts of the tube are liquid-tightly fixed to the cylindrical member 12, with the cylindrical member 12 inserted in the bored hole 10, the packer material 14 is forced to absorb water and swollen by using water 20 existing in the rubber tube 16 to pack up a gap between the hole wall and the cylindrical member 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention partially closes the gap between the wall surface of a boring hole formed in the ground and the outer peripheral surface of a tubular member inserted into the boring hole, and The present invention relates to a hole packing method in which a gas flow is blocked by a packer material. More specifically, the present invention uses a packer material made of a water-swellable polymer material, the outer side of which is liquid-tightly covered with a rubber tube, and water inside the rubber tube absorbs and expands the packer material to form a hole wall. The present invention relates to a method of packing a gap with a tubular member. This technique is particularly useful for water interception, for example in the field of groundwater investigations.

[0002]

2. Description of the Related Art When a boring hole is formed in the ground and various types of groundwater investigation such as pumping test, water permeability test, water level measurement, and pore water pressure measurement are performed, the boring hole should be placed at an appropriate position within the boring hole. It is necessary to partially close the gap between the wall surface of the casing and a cylindrical member such as a casing or a measuring instrument to be inserted therein by some packing means to block water.

Conventionally, as the water blocking technique, there have been an air packer method, a cement or bentonite grout method and the like. In recent years, as a technology capable of blocking water very easily,
A water blocking method using a packer material made of a water-absorptive polymer has been developed (see Japanese Utility Model Publication No. 1-171819). In this technique, a water-impervious packer material made of a water-swelling and expansive polymer material in the form of a band is wrapped around the outer peripheral surface of a tubular member and inserted into a boring hole, and groundwater existing in the boring hole is used. The packer material absorbs and expands the groundwater, thereby closing the gap and blocking water.

In this technique, the packer material has a very simple structure and can be manufactured at a low cost, and it can be easily attached to a tubular member. It is fixed by inserting it at a predetermined depth where groundwater exists and leaving it as it is. Since the expansion is automatically completed after a lapse of time and a good water-shielding effect is obtained, the water-shielding work is extremely easy, and has an excellent effect of high reliability and high reliability.

[0005]

However, this prior art has some limitations or drawbacks as follows. Packing is not possible where there is no water. There remains anxiety about water-blocking in places where the dryness and humidity are repeated, such as the part where the water level fluctuates. Usually, a water-swellable polymer material has some elution components, and is not suitable as a water-blocking material for groundwater investigations, which requires particularly detailed component analysis. It is difficult to block water because the amount of absorption and expansion is small in saltwater groundwater that is invaded by seawater. Since the polyacrylic acid ester used as the main component of the water-swellable polymer material elutes little by little as described above and is an organic substance, there is some concern about long-term measures such as several years or more.

The object of the present invention is to solve the above-mentioned limitations or drawbacks in use in the prior art while utilizing the advantages of the packer material made of a water-swellable polymer.
It is an object of the present invention to provide a hole packing method which can sufficiently cope with long-term use in places where there is no groundwater or where precise chemical analysis is required.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a method of inserting a tubular member inside a boring hole formed in the ground and packing the gap between the tubular member and the hole wall with a packer material. is there. In the present invention, the packing portion of the tubular member is surrounded in advance by a packer material made of a water-swellable polymer material, and a rubber tube is covered on the outer side of the packing member to liquid-tightly fix both ends to the tubular member. The packer material is water-expanded by using the water existing inside the rubber tube in a state where it is inserted into the boring hole, and the gap between the hole wall and the tubular member is packed.

According to the method of the present invention, before inserting the tubular member into the boring hole, a method of previously filling the inside of the rubber tube with a sufficient amount of water for the packer material to absorb and expand, and a rubber tube There is a method in which a water guiding pipe communicating with the inside is provided and a tubular member is inserted into the boring hole, and then water for causing the packer material to absorb and expand into the rubber tube through the water guiding pipe. In the method of injecting water later, the water is introduced into the boring hole in a state where the inside of the rubber tube has been evacuated using a water conduit in advance.

As the packer material, it is desirable to use a member formed by molding a water-swelling and expansive polymer material into a strip shape and wrap it around the outer peripheral surface of the tubular member. Natural rubber is suitable for the rubber tube covering the packer material. The rubber tube is liquid-tightly fixed to the tubular member by winding stainless steel wires or the like on both ends thereof.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A packer material made of a water-swellable and expansive polymer material is attached to the outside of a tubular member, and is inserted into a boring hole while being liquid-tightly covered with a rubber tube. Since the rubber tube is impermeable, the packer material does not come into contact with the groundwater or the like in the hole, but only comes into contact with the water inside the rubber tube. Therefore, even in places where there is no water in the borehole, or in saltwater groundwater,
The packer material absorbs water in the rubber tube and expands as much as necessary. Since the rubber tube is expandable and deformable in terms of material, it is deformed as the packer material expands, and the gap between the hole wall and the tubular member is packed. That is, in the present invention, reliable packing can be performed regardless of the presence or absence of groundwater at the packing location. Further, since the packer material is completely covered with the rubber tube and is isolated from the outside, even if the components of the packer material are eluted, they remain inside the rubber tube and do not affect the outside. In addition, it becomes possible to sufficiently withstand long-term use over several years.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing an embodiment of the hole packing method according to the present invention. In the figure, A indicates a state immediately after insertion, and B indicates a state in which the packer material is water-expanded and packed. A tubular member 12 such as a casing or a measuring instrument is inserted into the boring hole 10 formed in the ground. At this time, the packing portion of the tubular member 12 is provided in advance so as to surround the packing material 14 made of the water-swellable polymer material. And
A rubber tube 16 is covered on the outer side, and stainless steel wires 18 and the like are tightened at both ends to be liquid-tightly fixed to the tubular member 12. Then, the inside of the rubber tube 16 is filled with a sufficient amount of water 20 for the packer material 14 to absorb and expand.

The packer material 14 is made of a water-swellable polymer material as described above, which is, for example, a mixture of synthetic rubber and polyacrylic ester. As is well known, when this kind of material comes into contact with water, it takes in water molecules in its molecular structure, absorbs water, and at the same time has the effect of expanding its volume. The expansion rate can be changed. The material of the water-swellable polymer material is not particularly limited to the above. The packer material may be a ring-shaped molded body that matches the outer diameter of the cylindrical member, but a structure in which a band-shaped molded body is wound is preferable so that it can be applied to cylindrical members having various diameters.

An example of a mounted state of the packer material 14 is shown in FIG. Here, the packer material 14 is a molded body having a strip shape as a whole and having a plurality of ridges continuous in the longitudinal direction formed in the width direction. A packer material 14a having a flat surface on one side and a large number of ridges on the opposite surface is wound once such that the flat surface is in contact with the surface of the tubular member 12, and ridges are formed on both surfaces on the flat surface. The material 14b is wound so that the ridge and the groove are fitted to each other. The packing amount of the packer material 14 is such that the gap with the wall of the boring hole can be sufficiently closed due to its absorption and expansion performance. Although not shown in the drawing, the packer material 14 wound in layers is prevented from being displaced by attaching rubber bands or the like at both ends or by pressing with vinyl tape. If necessary, a wire may be wound around it and fixed.

The packer material 14 made of a water-swellable polymer material (mixture of synthetic rubber and polyacrylic acid ester) used in this embodiment absorbs about 60 times its own weight of water and expands in a similar manner. It has the property. However, when this packer material is used to block the flow of groundwater, in order to provide a sufficient expansion capacity so that it can be packed with sufficient pressure, the clearance (clearance) between the tubular member and the hole wall is set to about 1 mm.
Wrap it to have a thickness of / 2. Then, it is enough if there is 8 times more water than the weight of the packer material.
The rubber tube 16 may be filled with that amount of water in advance.

FIG. 3 shows a state in which the packer material 14 is wrapped around the tubular member 12 and a rubber tube 16 is covered therewith.
Shown in In the present embodiment, the rubber tube 16 is a molded body made of natural rubber, and has narrowed portions 16a and 16b formed at both ends thereof to have a reduced diameter so as to be in close contact with the surface of the tubular member 12. Replace the rubber tube 16 with the packer material 14
The tubular member 1 so that the rubber comes near the center of the rubber tube 16.
Put on 2. Then, a vinyl tape (not shown) is wound around the lower throttle portion 16a in a triple or quadruple manner for reinforcement. Further, in order to fix the rubber tube 16 so that water does not leak from the lower end, a stainless steel wire (not shown) having a thickness of about 1 mm is wound in three layers around the wound vinyl tape and tightened. Further, a vinyl tape (not shown) is further wound on the stainless steel wire to protect it from contact with the rubber tube 16 so that a piece of the stainless steel wire does not come into contact with the rubber tube 16. In this state, stand vertically to expel the air inside the rubber tube 16 and extend the upper throttle portion 16b to extend the rubber tube 1
Fill 6 with the required amount of water. Then, like the lower part, it is fixed to the tubular member.

Returning to FIG. 1, the tubular member 12 having the packer material 14 and the rubber tube 16 mounted therein is inserted to a predetermined position in the boring hole (see A in FIG. 1) and left at that position. The packer material 14 absorbs the water inside the rubber tube 16 and expands, closing the gap with the wall of the boring hole as shown in FIG. 1B. The water-expanded packer material 14 expands and deforms the rubber tube 16, and presses the wall surface of the boring hole 10 through the rubber tube 16.

In the present invention, the constraint conditions for the amount of water to be filled are the constraint imposed by the capacity of the rubber tube and the constraint caused by the relationship between the diameter of the rubber tube after water is added and the bore diameter. In other words, it is necessary to insert the hole wall without contacting the hole wall as much as possible. If the rubber tube is relatively small and the amount of water that can be put in without changing its shape is small, the rubber tube will swell downward as shown by the phantom line in FIG. 4 due to the weight of water when the necessary amount of water is injected. Become. In this state, since the diameter becomes large, contact with the hole wall is unavoidable during insertion into the boring hole. I use durable natural rubber as the material of the rubber,
Since it is necessary to minimize the contact, the upper squeezing part is pulled up as shown by arrow F to correct the downward bulging state (state shown by the solid line), and devise to prevent the diameter of the rubber tube from increasing extremely. . According to the results of the actual trial experiments, even if the amount of water that would deform the rubber tube was filled, the problem of contact with the hole wall surface did not occur when the rubber tube was pulled up slightly above as described above. Moreover, there was no problem in packing.

In an experiment in which a transparent acrylic pipe was used as a boring hole for packing in order to facilitate the observation and the gas blocking performance was investigated, the packing structure according to the present embodiment is the same as that of the packer material alone or is equal to that. It was found to have a better gas barrier effect than that. In the experiment, pressure was applied by supplying nitrogen gas from one end of the acrylic pipe, but even at a pressure of 1.3 kgf / cm ² , packer material, rubber tube, etc. did not move in the pipe axis direction, and good packing was achieved. It was confirmed that the state could be maintained. In the present invention, since the rubber tube is used on the outside, when actually applied to the packing of the boring hole, unlike the case of the packer material alone, the effect of the adhesion to the hole wall of the rubber tube is added, It is considered that the packing effect will be further improved.

FIG. 5 shows another embodiment of the hole packing method according to the present invention. In the figure, A shows a state immediately after the insertion of the tubular member, and B shows a state in which the packer material absorbs water and expands to be packed. The basic idea of this embodiment is the same as that of the previous embodiment. The tubular member 12 is inserted into the boring hole 10 formed in the ground. A packing material 14 made of a water-swellable polymer material is wound around the packing portion of the tubular member 12 in advance. Then, the rubber tube 16 is put on the outside thereof.
In this embodiment, it is not necessary to fill the inside of the rubber tube 16 with water in advance. The upper and lower squeezed portions of the rubber tube 16 are tightened with a stainless steel wire 18 or the like to be in a liquid-tight state. The feature of this embodiment is that the water conduit 22 is provided so as to communicate with the inside of the rubber tube 16. The water conduit 22 reaches the surface of the earth in a state where the tubular member 12 is inserted at a predetermined position in the boring hole, and may be a thin vinyl tube or the like. Then, before inserting the tubular member 12 into the boring hole, air is removed from the inside of the rubber tube by utilizing the water guide pipe 22 in advance. Then, the rubber tube 16 is brought into close contact with the tubular member 12 and the packer material 14. In this state, since the diameter can be minimized, the work of inserting the tubular member 12 into the boring hole can be performed very easily.

When the tubular member 12 is inserted so that the packer material 14 reaches a predetermined position, the water conduit 22 from the surface of the earth
Is used to inject water 20. Since the inside of the rubber tube 16 is preliminarily deaerated, water is easily injected into the inside of the rubber tube 16 through the water conduit 22.
As shown in FIG. 5B, the injected water absorbs and expands the packer material 14 made of a water-absorbent expansive polymer material, and expands the rubber tube 16 to close the gap with the hole wall.

In the above embodiment, a tube made of natural rubber is used in consideration of strength and easiness of manufacturing. This is optimal, but not necessarily so. Also, as the rubber tube, a molded body having narrowed diameters at both ends is used, but it is not always necessary to provide such narrowed portions if both ends can be firmly fixed liquid-tightly to the tubular member. .

When a large pressure difference is to be blocked by the method of the present invention, or when the hole wall has a large roughness, the structure in which the packer material is covered with a rubber tube as described above is used as a cylindrical member in multiple stages. It is possible to perform strong packing by disposing each of them in the above and absorbing and expanding them.

[0023]

As described above, the present invention is a method for absorbing and expanding the packer material by utilizing the water inside the rubber tube, so that it can be packed even in a place where there is no water, and the water level fluctuates and dry and wet are repeated. You can surely pack even in such places. Further, since the packer material is liquid-tightly covered with the rubber tube, the elution component from the packer material does not leak into the groundwater and does not hinder the accurate chemical analysis of groundwater. In addition, reliable water impermeability can be achieved regardless of salinized groundwater invading seawater. Furthermore, it can sufficiently withstand long-term use.

Since the present invention basically uses a packer material made of a water-swellable polymer material, it is said that its advantage is that it is lightweight and easy to work, and that it requires no skill in water-blocking work. It inherits the advantages as it is.

Furthermore, the present invention can be used not only for blocking the flow of groundwater but also for blocking the flow of gas in the boring hole because the packing can be performed in a place where there is no groundwater as described above. It is possible.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a hole packing method according to the present invention.

FIG. 2 is an explanatory view showing a state in which a band-shaped packer material is wound around an outer peripheral surface of a tubular member in a stacked manner.

FIG. 3 is an explanatory view showing a mounting state of a packer material and a rubber tube mounting method.

FIG. 4 is an explanatory view showing a state where water is injected into the rubber tube.

FIG. 5 is an explanatory view showing another embodiment of the hole packing method according to the present invention.

[Explanation of symbols]

 10 Boring Hole 12 Cylindrical Member 14 Packer Material 16 Rubber Tube 18 Stainless Steel Wire 20 Water 22 Water Pipe

Claims (4)

[Claims] 1. A method of inserting a tubular member into a boring hole formed in the ground and partially packing a gap between the tubular member and a hole wall with a packer material, wherein the tubular member is previously prepared. Enclose the packing part of with a packer material made of water-expandable polymer material, cover the outside with a rubber tube, fix both ends in a liquid-tight manner to the tubular member, and insert the tubular member into the boring hole. An in-hole packing method characterized in that the packer material is water-expanded by using water existing inside the rubber tube to fill the gap between the hole wall and the tubular member. 2. The hole packing according to claim 1, wherein before the cylindrical member is inserted into the boring hole, the rubber tube is previously filled with a sufficient amount of water for the packer material to absorb and expand. Method. 3. A water guiding pipe communicating with the inside of the rubber tube is provided, and the inside of the rubber tube is evacuated by using the water guiding pipe before inserting the tubular member into the boring hole. 2. The hole packing method according to claim 1, wherein water for causing the packer material to absorb water and expand is introduced into the rubber tube through the water conduit after being inserted into the inside. 4. The packer material is in the form of a strip, and the strip-shaped packer material is wound around the outer peripheral surface of a tubular member, and a rubber tube covering the packer material is made of natural rubber. The hole packing method according to claim 1, wherein the tubular member is liquid-tightly fixed using a stainless steel wire.