JP6663324B2 - Groundwater intake method and intake system - Google Patents

Description

  The present invention relates to a groundwater intake method and an intake system that can be suitably used for monitoring groundwater information (water pressure, flow rate, etc.) in front of a tunnel face, for example.

Large-scale springs (sudden springs) during tunnel excavation take measures behind the scenes, causing long-term suspension of construction. Therefore, it is important to grasp the groundwater information ahead of the tunnel face in advance.
Generally, monitoring is usually carried out at observation wells installed from the ground surface before construction starts. However, observation wells cannot be expected in a tunnel with a large overburden, and the actual situation is that the tunnel is being drilled while drilling from inside the tunnel. In addition, in the case of heavy earth cover, there is a concern that the spring zone also maintains a high spring pressure.

  In order to monitor the spring water pressure in front of the face during tunnel excavation, as shown in Patent Document 1, after drilling a borehole in the horizontal direction of rock, an intake pipe is inserted into the borehole, and an intake pipe is provided. It is necessary to install a packer between the outer peripheral surface of the hole and the inner peripheral surface of the boring hole.

  In this case, the installation position of the packer may be at the front of the boring hole or at the back of the boring hole. It is easier to install and remove the packer in front of the hole, but if the spring zone is deep in the hole, the spring pressure escapes from the wall surface of the borehole and the original water pressure behavior of the spring zone cannot be measured. Therefore, it is essential to install a packer in front of the target spring zone (inside the hole).

  In order to monitor the spring pressure in front of the tunnel, the drilling hole length is also important. For example, if the boring pressure can be measured by performing boring in the horizontal direction of a middle scale of 100 to 150 m, it is possible to obtain spring water information about one month ahead of the tunnel.

JP 2001-324575 A

  However, a drilling rod is used to form a horizontal boring hole of, for example, 100 to 150 m, and after the drilling rod is pulled out, an intake pipe having a packer on the outer periphery of the tip is inserted into the boring hole to expand the packer. If so, there are the following problems.

Before the packer is inserted together with the intake pipe, the above-mentioned section of 100 to 150 m becomes a blind hole, and there is a concern about collapse of the hole. For this reason, there is a concern that the packer is caught and cannot be inserted, and that even if it can be inserted, it cannot be collected.
For this reason, the actual situation is that there is almost no experience of inserting a packer in boring in the horizontal direction of a medium scale of 100 to 150 m.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a groundwater intake method and a water intake system that enable the intake of groundwater from the inside of a borehole.

Groundwater intake method according to the present invention ,
1) drilling with a first pipe having a drill bit at the tip to form a boring hole, and then retreating the first pipe;
2) Insert a second pipe having a packer on the outer periphery of the tip into the first pipe, push out the drill bit, and connect the tip of the second pipe to the tip face of the first pipe. More protruding,
3) expanding the packer so that the outer peripheral surface of the packer is in close contact with the inner peripheral surface of the boring hole;
4) Groundwater is taken in from the second pipe.

The groundwater intake system according to the present invention comprises:
A first pipe inserted into the boring hole, and a second pipe for water intake inserted into the first pipe and arranged so that a distal end thereof protrudes from a distal end surface of the first pipe. A packer mounted on the outer peripheral surface of the distal end portion of the second tube and expandable and contractable,
A drill bit is detachably attached to a tip of the first pipe, and the first pipe also serves as a drill pipe for the boring hole.
The drill bit is detachable from the first tube by pressing with the second tube,
In the contracted state, the packer can pass through the first pipe together with the second pipe, and in the expanded state, the outer peripheral surface can be in close contact with the inner peripheral surface of the boring hole.

Here, when a check valve is provided behind the drill bit in the first pipe, this check valve can also be detached from the first pipe by pressing by the second pipe. Good.
Further, the second pipe is a double pipe of an outer pipe and an inner pipe, and a water intake line is provided inside the inner pipe or between the outer pipe and the inner pipe, and the other is the expansion and contraction of the packer. It is good to use as a fluid line.

ADVANTAGE OF THE INVENTION According to this invention, hole collapse of a boring hole can be prevented using a 1st pipe as a hole keeping pipe, insertion of the 2nd pipe which has a packer becomes easy, and a packer can be arrange | positioned at the back of a hole. .
In addition, the first pipe is used as a drilling pipe, and the drilling bit (and the check valve) is pushed out by the second pipe, so that the first pipe separates the drilling pipe and the borehole pipe. At the same time, this eliminates the need for removing the drilled pipe, thereby improving work efficiency. Further, at the time of drilling, since the drilling is performed only with the first pipe (single pipe), the driving force can be easily transmitted and the required drilling length can be secured as compared with the case of drilling with the double pipe.
In addition, by securing the fluid line for packer expansion by using the second tube as a double tube, it is not necessary to separately lay the tube, and the insertion operation can be facilitated.

Process diagram showing one embodiment of the groundwater intake method according to the present invention The figure which shows the specific example 1 of the detachment mechanism of a 1st pipe and a drilling unit. The figure which shows the specific example 2 of the detachment mechanism of a 1st pipe and a drilling unit. FIG. 6 is a diagram showing a distal end structure of a first tube as another embodiment.

Hereinafter, embodiments of a groundwater intake method and an intake system according to the present invention will be described with reference to the drawings. Here, the intake of groundwater is performed for measuring the pressure or flow rate of groundwater.
FIG. 1 is a process chart showing an embodiment of a method for collecting groundwater (measuring method) according to the present invention. Hereinafter, each process will be described.

FIG. 1A shows a drilling step using a first pipe (drilling pipe) 3.
A first pipe (drilling pipe) 3 having a drilling unit 2 (including a drilling bit 2a) attached to a tip end thereof is rotated by a drilling machine 1 from inside the tunnel, and a boring hole 4 is formed in the ground. Drill holes.
The drilling machine 1 may be a rotary drilling system for rotating and driving the drilling tube to perform a feed operation, or a rotary percussion drilling system for rotating and driving the drilling tube to perform a hitting operation in a feed direction. Is also good.
The drilling machine 1 also has a function of supplying water for cooling and draining into the first pipe 3.

The drilling unit 2 is integrally formed as a unit including a drilling bit 2a, a check valve 2b, and a mounting portion (engaging portion) 2c.
The drill bit 2a is configured by arranging a plurality of bits in a ring shape on the tip end surface, and has a water outlet for cooling and discharging mud.
The check valve 2b allows water for cooling and sludge to pass only in a direction to be sent to the drill bit 2a, and prevents backflow from the drill bit 2a into the first pipe 3.
The attachment portion 2c is a portion for detachably (removably) attaching the drilling unit 2 to the first pipe 3, and transmits the rotation of the first pipe 3 to the drill bit 2a. However, the drilling unit 2 can be detached from the first pipe 3 by pushing the drilling unit 2 (the mounting portion 2c) from inside the first pipe 3. A specific example of the detachment mechanism will be described later.

  The cooling and muddy water supplied into the first pipe 3 is ejected from the drill bit 2a through the check valve 2b, and then the inner peripheral surface of the boring hole 4 and the outer circumference of the first pipe 3 are discharged. It returns to the hole side through the gap with the surface. At this time, excavation debris of the rock excavated by the drill bit 2a is discharged to the outside of the boring hole 4 together with the muddy water.

The hole side of the boring hole 4 is enlarged in diameter and reinforced by a mouth protection tube 5 having a diameter larger than that of the first tube 3.
A preventer 6 is attached to the opening of the mouth protection tube 5 so as to surround the first tube 3.
The preventer 6 has an annular bag extending over the entire inner surface of the tube, and the bag expands and contracts by controlling the supply of air or water, so that the inner surface of the preventer 6 and the first surface are connected to each other. The gap with the outer peripheral surface of the tube 3 can be adjusted.
A drain line 7 having an on-off valve is also connected to the mouth protection tube 5, and the water for cooling and mud returning to the hole side is discharged from the drain line 7.

  As the boring by the first pipe 3 progresses, the first pipe 3 is added on the drilling machine 1 side, and a desired drilling length (for example, 100 to 150 m) is excavated and drilled.

FIG. 1B shows a step of retracting the first pipe (drilled pipe) 3.
In this step, after the desired drilling length is achieved, drilling (and supply of water for cooling and drainage) is stopped, and the first pipe 3 is retracted by a predetermined distance. For example, the fact that the water has passed the spring zone is known from the increase in the amount of drainage due to the spring water, and the first pipe 3 is pulled back to just before the spring zone. Thereby, a space is formed between the tip of the boring hole 4 and the tip of the first pipe 3. This space serves as a detachable space for the drilling unit 2 and an expanded space for the packer 9. Note that even under high spring pressure, spring water (groundwater) is prevented from entering the first pipe 3 by the check valve 2b and escapes into the gap between the first pipe 3 and the boring hole 4. Tube 3 can be safely retracted.

FIG. 1C shows a step of inserting the second pipe (intake pipe) 8.
In this step, a second pipe (water intake pipe) 8 is inserted into the first pipe (drilled pipe) 3. The second tube 8 has a packer 9 on the outer periphery of the distal end portion. When the packer 9 is in the contracted state, the outer diameter of the packer 9 is smaller than the inner diameter of the first tube 3. Also at the time of insertion, the inflow of the spring water into the first pipe 3 is prevented by the check valve 2b, so that the second pipe 8 can be safely inserted even under a high spring water pressure. Further, as the insertion proceeds, the second pipe 8 is added to the rear end side of the second pipe 8. Thereby, the front end of the second pipe (water intake pipe) 8 is brought into contact with or close to the rear end of the drilling unit 2. Although omitted in FIG. 1C, the insertion of the second pipe 8 may be performed using the drilling machine 1.

  The second pipe 8 has a double pipe structure of an outer pipe 8a and an inner pipe 8b, and the inside of the inner pipe 8b serves as a water intake line when groundwater is taken. The space between the outer pipe 8a and the inner pipe 8b becomes a fluid line (air or water supply line) for expanding and contracting the packer 9.

FIG. 1 (D) shows a lip treatment and a drilling unit detachment process.
In the lip treatment step, the preventer 6 is removed from the lip protection tube 5, and the opening of the lip protection tube 5 is closed with a lid 10. Further, the on-off valve 11 is set (closed state) at the mouth of the second pipe 8, specifically the inner pipe 8b, and the pressure gauge 12 and the flow meter 13 are set upstream of the on-off valve 11 as measuring instruments.

  In the drilling unit detachment step, the drilling unit 2 is pushed by further pushing the second pipe 8 in the insertion direction from a state where the tip of the second pipe 8 is in contact with or close to the drilling unit 2. Remove from the first tube 3. Then, the tip of the second tube 8 (the portion of the packer 9) is made to protrude from the tip of the first tube 3.

FIG. 1E shows a packer expansion and measurement process.
In the packer expanding step, air or water is sent to the packer 9 through the packer expanding / contracting fluid line between the outer pipe 8a and the inner pipe 8b of the second pipe (intake pipe) 8, and the packer 9 is moved to the outer peripheral side. Let it expand. Thereby, the outer peripheral surface of the packer 9 is brought into close contact with the inner peripheral surface of the boring hole 4. As a result, the gap between the outer periphery of the distal end portion of the second pipe 8 and the bore hole 4 is sealed by the packer 9, and the flow from the spring zone to the outside of the second pipe 8 is prevented. Of the groundwater is taken into the second pipe 8.

In the measurement step, when measuring the water pressure of the groundwater, the on-off valve 11 is closed, and the water pressure is measured from the indicated value of the pressure gauge 12.
When measuring the flow rate of the groundwater, the on-off valve 11 is opened, and the flow rate is measured from the indicated value of the flow meter 13.
Such measurements are made as needed, eg, during a monitoring period of several months.

After the monitoring is completed, air or water is removed from the packer 9 through the packer expanding / contracting fluid line, and the packer 9 is contracted. Thereafter, the second tube 8 having the packer 9 is pulled out through the first tube 3. In addition, by leaving the first tube 3 during the monitoring period (for example, several months), it is possible to safely carry out the removal of the second tube 8.
Next, the first tube 3 is pulled out. Therefore, the removed drilling unit 2 is not recovered.

Next, a specific example of the detaching mechanism of the drilling unit 2 will be described.
FIG. 2 is a view showing a specific example 1 of a detachment mechanism between the first pipe 3 and the drilling unit 2.
In this example, the inner periphery of the distal end portion of the first pipe 3 and the outer periphery of the mounting portion 2c at the rear end of the drilling unit 2 are fitted to each other and provided with a key block 21 provided radially through the mounting portion 2c. , In the direction of rotation. On the other hand, in the axial direction, the key block 21 can be detached by the engaging slope 21a. The key block 21 is fixed to a fixing ring 23 fitted on the inner periphery of the mounting portion 2c by a fixing pin 22. The fixing pin 22 can be pushed and cut off.

  Therefore, by pressing the mounting portion 2c at the rear end of the drilling unit 2 with the front end of the second pipe 8, in combination with the movement of the key block 20 along the engaging slope 20a, the fixing pin 22 is pushed off, and the key block is pushed. 20 can be removed, and the drilling unit 2 can be detached from the first pipe 3.

  That is, the drilling unit 2 (including the drilling bit 2a) is firmly engaged with the distal end of the first tube 3 via the key block 21 in the rotational direction and weakly in the axial direction (particularly in the separating direction). The drilling unit 2 can be removed by pressing the drilling unit 2 with the second pipe 8 in a direction to separate the drilling unit 2 from the first pipe 3.

FIG. 3 is a view showing a specific example 2 of a detachment mechanism between the first pipe 3 and the drilling unit 2.
In the present example, an engagement groove 31 that opens in the rotation direction at the time of drilling is provided at the distal end 3 a of the first pipe 3, and an engagement pin is 32.
The engagement groove 31 and the engagement pin 32 are engaged in the rotation direction when drilling the first pipe 3 and transmit the rotation of the first pipe 3 to the drilling unit 2 (the drill bit 2a). .

  Therefore, the first pipe 3 is rotated in the direction opposite to the rotation direction at the time of drilling, the engagement between the engagement groove 31 and the engagement pin 32 is released, and then the tip of the second pipe 8 is drilled. By pressing the rear end of the hole unit 2, the hole drilling unit 2 can be detached from the first pipe 3.

  That is, the drilling unit 2 (including the drilling bit 2 a) is provided at the tip of the first pipe 3 with the engaging groove 31 and the engaging pin 32, and the rotation direction at the time of drilling the first pipe 3. After the first tube 3 is reversed to release the engagement, the drilling unit 2 is removed by pressing the drilling unit 2 with the second tube 8. Can be.

According to the present embodiment,
1) After drilling with a first pipe (drilling pipe) 3 having a drilling unit 2 (including a drilling bit 2a) attached to the tip to form a boring hole 4, the first pipe 3 is retracted. Let
2) Insert a second pipe (water intake pipe) 8 having a packer 9 at the outer periphery of the tip into the first pipe 3 and push out the drilling unit 2 to remove the tip of the second pipe 8 into the second pipe. Project from the end face of the tube 1
3) Expand the packer 9 so that the outer peripheral surface of the packer 9 is in close contact with the inner peripheral surface of the boring hole 4,
4) Take groundwater from inside the second pipe 8.

By adopting such a process, it is possible to prevent the borehole 4 from collapsing by using the first pipe 3 as a hole retaining pipe, facilitate the insertion of the second pipe 8 having the packer 9, and remove the packer 9 from the hole inside. Can be arranged.
The first pipe 3 is used as a drilling pipe, and the drilling unit 2 (including the drilling bit 2a) is pushed out by the second pipe 8 so that the first pipe 3 is drilled. The hole also serves as a hole retaining pipe, which makes it unnecessary to remove the drilled pipe, thereby improving the working efficiency. In drilling, only the first pipe 3 (single pipe) is drilled, so that the driving force can be easily transmitted and the required drilling length can be secured compared to drilling with a double pipe. Also, the drilling time can be reduced.

  Further, according to the present embodiment, the check valve 2b for preventing the backflow of the water for drainage is provided behind the drill bit 2a in the first pipe 3; By pushing off the check valve 2b when pushing out the drill bit, it is possible to prevent the check valve 2b from obstructing the intake of groundwater and to ensure the intake of groundwater.

Further, according to the present embodiment, the second pipe 8 is a double pipe of the outer pipe 8a and the inner pipe 8b, and is provided inside the inner pipe 8b or between the outer pipe 8a and the inner pipe 8b. One of them can be a water line, and the other can be a fluid line for expanding and contracting the packer 9. Then, the following effects can be obtained.
When the second pipe 8 for inserting the packer 9 is a single pipe, if the inside of the pipe is used as a water line, it is necessary to separately lay a fluid line (tube) for expanding and contracting the packer 9. Not only is it bothersome, but there is a concern that the fluid line (tube) may be damaged or cut on the way.
Therefore, as in the present embodiment, by using a double pipe which can be used separately for a water intake line for monitoring water pressure and the like and a fluid line for expanding and contracting the packer 9, insertion work becomes extremely easy.

  According to the present embodiment, a measuring device (a pressure gauge 12 and a flow meter 13) is arranged at the mouth side of the second pipe 8 to measure the water pressure or the flow rate of the groundwater. The situation can be monitored safely.

In the above-described embodiment, the check valve 2b disposed behind the drill bit 2a in the first pipe (drilled pipe) 3 and preventing the backflow of water for cooling and drainage is provided by the drill bit. 2a and a unit (boring unit 2).
FIG. 4 shows another embodiment of the present invention in which the check valve is configured differently from the drill bit. In the present example, a drill bit 2a is attached to the tip of the first pipe (drilled pipe) 3 via an attachment portion 2c. The check valve 2b is fitted at a position behind the drill bit 2a in the first pipe 3.
In this case, by inserting the second pipe 8 into the first pipe 3, the check valve 2b is pushed out first, and then the drill bit 2a is pushed out, whereby these can be dropped.

  Further, in the above embodiment, the first pipe 3 having the drilling unit 2 (including the drill bit 2a) attached to the tip serves as both the drilling pipe and the retaining pipe. A step of detaching the drilling unit 2 with the pipe 8 is performed. After the drilling rod is pulled out into a boring hole previously formed by a drilling rod (including a drill rod, a boring rod, a casing rod, etc.), the first drilling rod is removed. The tube 3 may be inserted as a hole retaining tube. In this case, the step of detaching the drilling unit 2 becomes unnecessary.

That is,
1) Insert and arrange the first pipe (hole pipe) 3 in the boring hole 4,
2) Insert a second pipe (water intake pipe) 8 having a packer 9 around the distal end into the first pipe 3 so that the distal end of the second pipe 8 is positioned at the distal end surface of the first pipe 3. More protruding,
3) Expanding the packer 9 so that the outer peripheral surface of the packer 9 is in close contact with the inner peripheral surface of the boring hole 4,
4) Take groundwater from inside the second pipe 8.

  Also in this case, it is possible to prevent the borehole 4 from collapsing by using the first pipe 3 as a hole retaining pipe, facilitate the insertion of the second pipe 8 having the packer 9, and place the packer 9 at the back of the hole. Can be arranged.

  Further, the illustrated embodiments are merely examples of the present invention, and the present invention is not limited to those directly described by the embodiments described above, and includes various improvements and modifications made by those skilled in the art within the scope of the appended claims. It goes without saying that the changes are included.

DESCRIPTION OF SYMBOLS 1 Drilling machine 2 Drilling unit 2a Drilling bit 2b Check valve 2c Mounting part (engaging part)
3 First pipes (drilled pipes, bored pipes)
4 Boring hole 5 Mouth protection tube 6 Preventer 7 Drain line 8 Second pipe (intake pipe)
8a outer pipe 8b inner pipe 9 packer 10 lid 11 on-off valve 12 pressure gauge 13 flow meter

Claims (8)

After drilling with a first pipe having a drill bit at the tip to form a boring hole, the first pipe is retracted,
A second pipe having a packer on the outer periphery of the tip is inserted into the first pipe, the drill bit is pushed out, and the tip of the second pipe projects from the tip surface of the first pipe. Let
Expanding the packer, bringing the outer peripheral surface of the packer into close contact with the inner peripheral surface of the boring hole,
A method for drawing groundwater, comprising drawing groundwater from the second pipe. A check valve provided rearward of the drill bit in the first pipe;
2. The method according to claim 1 , wherein when the drill bit is pushed off by the tip of the second pipe, the check valve is also pushed off. 3. The second pipe is a double pipe of an outer pipe and an inner pipe, and one of the inner pipe and the one between the outer pipe and the inner pipe is a water intake line, and the other is a pipe for expanding and contracting the packer. 3. The method according to claim 1 , wherein the groundwater is a fluid line. The groundwater intake method according to any one of claims 1 to 3 , wherein a measuring device is arranged at a mouth side of the second pipe to measure a water pressure or a flow rate of the groundwater. A system for collecting groundwater from a borehole,
A first pipe inserted into the boring hole;
A second pipe for water intake which is inserted into the first pipe and whose distal end is disposed so as to protrude from the distal end surface of the first pipe;
A packer which is mounted on the outer peripheral surface of the distal end portion of the second tube and is expandable and contractable;
Is composed of
A drill bit is detachably attached to a tip of the first pipe, and the first pipe also serves as a drill pipe for the boring hole.
The drill bit is detachable from the first tube by pressing with the second tube,
In the contracted state, the packer can pass through the first tube together with the second tube, and in the expanded state, the outer peripheral surface can be in close contact with the inner peripheral surface of the boring hole, Groundwater intake system. A check valve provided rearward of the drill bit in the first pipe;
The groundwater intake system according to claim 5 , wherein the check valve is also detachable from the first pipe by being pressed by the second pipe. The second pipe is a double pipe of an outer pipe and an inner pipe, and one of the inner pipe and the one between the outer pipe and the inner pipe is a water intake line, and the other is a pipe for expanding and contracting the packer. The groundwater intake system according to claim 5 or 6, wherein the system is a fluid line. The groundwater intake system according to any one of claims 5 to 7 , further comprising a water pressure or flow rate measuring device arranged at a mouth side of the second pipe. .