JP2628525B2 - Borehole measuring device for lock anchor and lock anchor construction method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a borehole measuring device for a rock anchor suitable for preventing rock collapse on a steep slope or the like, and a rock anchor construction method using the same.

[0002]

2. Description of the Related Art FIG. 18 is a view showing an example of a conventionally proposed lock anchor construction method. Usually, the rock anchor forms a borehole from the rock surface by drilling from the rock surface to the rock to be anchored, via a scaffold or the like provided facing the rock surface forming the slope. In addition, the rock material is tightened and strengthened by placing an anchor material, an injection material, and the like in the borehole, thereby preventing expected rock collapse. By the way, recently, for various reasons such as the purpose of maintaining the landscape, the limitation of the slope and the topography of the site, and the difficulty in maintaining safety during construction, it is difficult to maintain the rock mass from the rock surface side. There is an increasing demand to use rock anchors to fasten rocks even on slopes where it is not possible to construct anchors. Therefore, as shown in FIG. 18, a shaft 39 is dug down near the cliff surface 40 where collapse is expected and along the cliff surface 40.
9, a rock hole is formed by penetrating a bore hole 38 so as to connect the two 39, 40 toward the cliff surface 40, and a rock anchor is driven into the bore hole 38 formed from the shaft 39 side. Construction methods of lock anchors are being proposed. In this case, since the lock anchors must be accurately cast so as to be arranged immediately before the tips of the lock anchors protrude from the cliff surface 40, lock anchors having different lengths LBn are provided one by one. It will be cast.

[0003]

However, since the cliff surface 40 has large and small undulations, a through hole is formed from the shaft 39 toward the cliff surface 40 so that it is determined in the design stage. It is very difficult to obtain a perforated length corresponding to the length of the borehole, and therefore, the length of the borehole 38 formed through the insertion length of the lock anchor is arranged in such a manner that the anchor tip is disposed immediately before protruding from the cliff surface 40. In order to accurately correspond to the above, it is essential to check the length of the bore hole 38 at the time when the bore hole 38 is pierced. So, in order to perform a scale,
An observation worker 43 is placed on standby on a hill or the like where a cliff surface 40 can be seen by sandwiching a valley 41 or the like. When the drilling operation is completed, the anchor preparing operator 44 on the shaft 39 causes the measuring operator 45 in the shaft 39 to insert the measuring rod 37 into the bore hole 38 while waiting. The observation operator 43 visually confirms through the telescope 46 that the tip 37a of the measuring rod 37 protrudes from the borehole end 38a, and communicates this via a signal S1 such as a radio signal. Signal S1
The length of the insertion of the measuring rod 37 at the point when is output is read by the measuring operator 45. Then, a method has been tried in which an anchor body is cast into the bore hole 38 just measured by a length corresponding to the length of the bore hole 38 to be measured. However, such a method is performed via the signal S1.
There is a drawback that the measuring operation must proceed while communicating with the persons 43, 44 and 45, which is complicated and inefficient, and that much time is spent for the measuring operation. In addition, since the borehole length is determined by the signal S1 issued by visual confirmation from a distant position, the measurement accuracy is poor. Depending on the error in the measurement accuracy, the tip end of the lock anchor may be higher than the cliff surface 40. There is a concern that the view of the cliff surface 40 may be degraded or the function of the lock anchor may be impaired by protruding the valley 41. In addition, this method
The observation operator 43 required to visually check the tip 37a of the measuring rod 37 needs to be arranged at a position facing the cliff surface 40 so as to overlook the cliff surface 40.
Accordingly, since the observation operator 43 is dedicated to the observation operation at a position far away from the shaft 39, the observation operator 4 is not required to perform the scale measurement operation by such a method.
Unless the labor required for step 3 is secured, the number of construction personnel related to anchor loading preparation work and the like to be advanced near the shaft 39 in parallel with the scale measurement work decreases. There was an inconvenience that work efficiency was reduced. Therefore, the present invention, in view of the above circumstances,
A borehole measuring device for a lock anchor, wherein the length of the borehole formed through the hole can be easily and accurately measured by only one operator through only one end side of the borehole; And a method for constructing a lock anchor using the measuring device.

[0004]

That is, the present invention relates to a method for controlling a predetermined length
Each of the rods has a freely extendable rod (26), and a distal end side of the rod.
Provided with a detection unit (25a, 31), and the detection unit is configured to detect a hole wall.
Informing means (32, 33) and hole wall detection by said hole wall detecting means
A signal output means (3) for outputting a predetermined signal according to the state;
5), which is determined according to a signal from the signal output means.
An output means (28) for displaying the above is provided to constitute a borehole measuring device (25) for a lock anchor. A shaft (3) is dug down near the rock surface (20) to be prevented from collapsing along the rock surface (20), and a side wall of the shaft (3) is formed from inside the shaft (3). By drilling a rock (2) so as to connect the rock surface (20) with the rock surface (3a), a borehole (22) is formed through the borehole (2), and the borehole (2) penetrated from the inside of the shaft (3) is formed.
2) Into the lock anchor borehole measuring device (25), the length of the borehole (22) is detected, and the lock anchor borehole measuring device (25) is inserted into the borehole (22). ), The anchor member (6) is inserted by a length corresponding to the length of the borehole (22) detected through the hole (22), whereby the distal end (7) of the anchor member (6) is inserted into the borehole (22). Is arranged at a position corresponding to the rock surface (20). The numbers and the like in parentheses are for convenience showing the corresponding elements in the drawings, and therefore, the description is not limited to the description on the drawings. The same applies to the following operation columns.

[0005]

With the configuration described above, the present invention provides a detecting unit (3
1) causing the output means (28) to output information as to whether or not 1) has detected the hole wall (22b) of the borehole (22), and whether the detection unit (31) is disposed in the borehole (22). By determining whether or not the borehole (22)
The extension length of the rod (26) inserted therein is detected to act to measure the length of the borehole (22). The anchor member (6) inserted into the borehole (22) has a tip (7) disposed at a position corresponding to the rock surface (20), and the shaft member (6) and the shaft (3). )
Acts to reinforce the rock mass (2) disposed between the rock mass (2) and the side wall (3a).

[0006]

1 is a cross-sectional side view of a mountain to which a method of constructing a lock anchor according to the present invention is applied, FIG. 2 is a view taken in the direction of the arrow II in FIG. 1, and FIG. FIG. 4 is a sectional view taken along arrows IV and IV in FIG. 3, FIG. 5 is a sectional view taken along arrows V and V in FIG. 3, and FIG. 6 is used in the lock anchor construction method shown in FIG. FIG. 7 shows an example of a borehole measuring device for a lock anchor, FIG. 7 is an enlarged sectional view showing a rod portion in the borehole measuring device for a lock anchor shown in FIG. 6, and FIG. 8 is a borehole measuring device for a lock anchor shown in FIG. 9 is an enlarged side view showing the hole wall detecting unit in FIG. 9, FIG. 9 is a top view as viewed from the direction of the arrow IX in FIG. 8, and FIG. 10 is a perspective view showing an example of a limit switch applied to the lock anchor borehole measuring device shown in FIG. 11 to 17 show a method of installing a lock anchor according to the present invention. It is a series of figures showing a construction procedure of a law.

As shown in FIG. 1, a mountain 1 where collapse is expected is a rock surface to be prevented from collapsing, and a cliff 20 which rises substantially vertically is directed to a valley 21 shown in the right part of FIG. It has a rock 2 formed in an irregular shape, and on the upper layer side of the rock 2, sediment 2a slightly weaker than the rock 2 is deposited. Earth and sand 2
The top soil 2b is deposited on the upper layer side of the
Has a shape in which a crown 2c is formed on the mountain 1. Also,
In the mountain 1, the shaft 3 is dug down substantially vertically toward the inside of the bedrock 2 at a position separated from the cliff surface 20 by a predetermined distance substantially L2 to the left side of FIG. The shaft is formed into a columnar shape having a predetermined diameter D1 and is formed by excavation only to a predetermined depth L1. On the outer periphery of the shaft 3, a concrete having a predetermined strength constituting a side wall of the shaft 3 is formed. 3
a is cast and disposed in a cylindrical shape having a winding thickness W1 in a form reinforced and reinforced by a shoring, a lock bolt or the like (not shown). In addition, at the top of the shaft 3, a rolled concrete 3
A head concrete 3b having the same strength as that of a is cast and formed in the form of a hollow hole at the top 2c so as to support and support the pit portion of the shaft 3.

As shown in FIG. 2, an expected collapse area 20p is set on the cliff surface 20 in a form corresponding to the area surrounded by the dashed line in FIG. The rock mass 2 on the side, that is, on the left side of FIG. The rock 2 disposed between the rock 3a and the rock 3a is maintained in a sufficiently stable and predetermined strength in a form reinforced by fastening. That is, as shown in FIG. 2, a predetermined number of lock anchors 5 form predetermined pitches P1, P2 in the vertical direction and the horizontal direction in FIG. As shown in FIG. 1, each of the rock anchors 5 has a cliff surface 2 in an area corresponding to the shaft 3 and the expected collapse range 20p.
0 in a substantially horizontal direction shown in FIG.
It is established in each.

As shown in FIGS. 3 to 5, the lock anchor 5 has a predetermined length L3 of a predetermined number (three in this embodiment) of PC steel strands as an anchor member of the lock anchor 5. An anchor body 6 is formed, and the anchor body 6 is formed in a rock mass 2 in a borehole 22 formed through a hole connecting the shaft 3 and a cliff surface 20, each of which has a predetermined length L4. The bore 6 is disposed in the shaft 3 from the left end side in FIG. 3 with the head 6a of the anchor body 6 projecting therefrom. The head 6a is provided with a tapered washer 12 through which the anchor body 6 can be inserted so as to be disposed on the shaft 3 side of the rolled concrete 3a shown on the left side of FIG. Is the bearing base 13
An anchor head 15 is fitted and attached to the anchor body 6 in such a manner that the anchor body 6 can be freely fixed in tension. On the other hand, on the right end side in FIG. 3 which is the tip of the anchor body 6, a pilot cap 7 made of aluminum or the like constituting the tip of the anchor body 6 is located at a position corresponding to the cliff surface 20. The anchor member 6 is fitted to the anchor body 6 so as to be slightly disposed on the side of the rock 2, and the anchor body 6 is formed of a steel pipe or a resin pipe or the like for injecting and exhausting or pressurizing the fixing material 16. Some of the pipes 9 are arranged along the direction in which the anchor body 6 extends, with the positions of the open ends 9a thereof being different from each other.

Around the right end of FIG. 3, which is the tip of the anchor body 6, a primary fixing portion 6 having a predetermined length L5 is formed.
In the primary fixing portion 6b, a cloth packer 10a made of aramid fiber or the like is provided around the pipe 9 in which the anchor body 6 and its open end 9a are arranged in the primary fixing portion 6b. In the form of covering, both ends of the wire 10c
It is disposed in a tubular shape sealed through the like. A ring 11a for bundling the anchor body 6 and a pipe 9 disposed therein and the anchor body 6 are provided on the primary fixing portion 6b.
A predetermined number of spacers 11b for accurately maintaining the mutual positions of the pipes 9 and the pipes 9 are disposed at predetermined positions. These anchor bodies 6, the pipes 9, the rings 11a, the spacers 11b, and the like are arranged in the cloth packer 11a. And is embedded in a fixing material 16 made of cement milk or the like which is injected and filled into the fixing material 16. Further, the shaft 3 is moved from the primary anchoring portion 6b of the anchor body 6.
The left side of FIG. 3 is provided with a secondary fixing unit 6c having a predetermined length L10, and the secondary fixing unit 6c includes:
Cloth packer 1 made of the same material as cloth packer 10a
0b covers the periphery of a pipe 9 in which the anchor body 6 and its open end 9a are disposed in the secondary fixing portion 6c, and the both ends of which are sealed via a wire 10c or the like. It is arranged in. In the cloth packer 11b of the secondary fixing section 6c, the same fixing material 16 as that injected and filled in the primary fixing section 6b is injected and filled.
Cloth packer 11 of primary fixing unit 6b and secondary fixing unit 6c
Substantially the entire length is fixed to the bedrock 2 via the fixing material 16 injected and filled in each of a and 11b. In addition, on the left side of FIG. 3 which is on the side of the shaft 3 from the secondary anchoring portion 6c of the anchor body 6, a free length portion 6d is provided between the anchor body 6 and the head 6a.
Is provided for a predetermined length obtained by subtracting the length of the head 6a, the primary fixing portion 6b, and the secondary fixing portion 6c from the length L3 of the anchor body 6, and the free length portion 6d has ,
The fixing material 16 is not filled and the free long portion 6d is provided with a gas nozzle 9b capable of supplying and discharging gas.

As a borehole measuring device for a lock anchor for measuring the length L4 of the borehole 22 for placing the lock anchor 5, a measuring device 25 as shown in FIG. 6 is used. The measuring device 25 includes a plurality of rods 2 that are extended and connected in a form corresponding to the length of the borehole 22.
6. As shown in FIG. 7, for example, each rod 26 has a predetermined length L6 in the left-right direction in FIG. 7, and a female screw 26a is formed at one end shown at the right end in FIG. A male screw 26 is attached to the other end shown on the left side in FIG.
It is constituted by a steel pipe member or the like on which b is formed. Between the adjacent rods 26, 26, a reducing nipple 27 is fitted and mounted so as to connect and integrate the rods 26, 26, and an electric signal is provided in the plurality of connected rods 26. A cable 29 through which S2 can flow is inserted through the plurality of connected rods 26 so as to continuously penetrate the inside thereof. At the upper left side of FIG. 6 that is the base side of the cable 29, an indicator light 28 is connected in a freely lit manner, and the indicator light 28 is configured to be illuminated via a signal S2 transmitted by the cable 29. I have.

At the right end in FIG. 6 of the measuring device 25, there is provided a hole wall detecting portion 25a which constitutes a tip portion of a plurality of connected rods 26 of the measuring device 25. The detecting unit 25a is a female screw 26a of the rod 26 disposed at the right end of FIG.
And a casing 30 in which the screw portion 30b is fitted.
have. The casing 30 is, as shown in FIG.
The maximum outer diameter is D2, and the distal end side is formed in the shape of a hollow container having a tapered shape. The maximum outer diameter D2 of the casing 30 is equal to the diameter of the pilot portion 22a which is the leading end of the bore hole 22 shown in FIG. It has a slightly smaller diameter than D4. The casing 30 has an opening window 30.
a has a predetermined length L7 and an opening is formed at a position shown in the upper part of FIG.
0, a limit switch 31 such as a roller lever type contact type, which constitutes a detection unit of the measuring device 25,
Is a roller 3 serving as a detection member of the limit switch 31.
2 are housed so as to protrude outside the casing 30 through the opening window 30a.

As shown in FIG. 10, a lever 33 made of a steel plate is pivotally connected to the limit switch 31 via a pin 331 which is mounted in the lower part of FIG. The pin 33 is provided so as to be swingable in the directions of arrows C and D.
The roller 32 is mounted so as to be rotatable in a direction parallel to the plane of FIG. An operation unit 35 is connected to the limit switch 31 so that the indicator lamp 28 can be turned on and off via the cable 29 by the operation of the operation unit 35. That is, the lever 33 is in the normal state,
That is, when the roller 32 is in the released state, the swing axis of the lever 33 is held in the vertical direction in FIG. 10, and the operating unit 35 moves the roller 3 shown in FIG.
(2) In the released state, the circuit is connected to turn on the indicator lamp 28 via the cable 29, while the roller 32 swings in the directions of arrows C and D. That is, the circuit is cut off so as to turn off the indicator lamp 28, so that it can be switched freely. Accordingly, the limit switch 31 determines whether or not the roller 32 is in contact with the hole wall 22b of the bore hole 22 when the roller 32 is inserted into the borehole 22 and inserted into the borehole measuring device 25 depending on the operation state of the operation unit 35. In the output form, the hole wall 22b is detectable, and the indicator light 28 indicates whether the limit switch 31 is detecting the hole wall 22b.
Is configured to constitute the output means of the measuring device 25 in a form that can be distinguished outside. When the roller 32 is in the released state as shown in FIG. 10, the limit switch 31 makes the swing axis of the lever 33 form a predetermined distance L8 from the left end in FIG. 8, which is the base end of the casing 30, and 8 is arranged and accommodated in the casing 30 so that the height in the vertical direction forms a distance H1 slightly larger than the outer diameter D4 (shown in FIG. 11) of the pilot portion 22a in the borehole 22.

Since the ridge 1 and the lock anchor 5, which are expected to collapse, and the measuring device 25 and the like have the above-described configurations, the ridge 1 collapses with a predetermined number of lock anchors 5.
The anchor member 6 serving as the anchor member is struck and set in the rock 2 so as to connect the rolled concrete 3a of the shaft 3 and the cliff surface 20 in a region corresponding to the expected collapse range 20p, and thus lacks independence stability. The rock 2 in the state is prevented by fastening and reinforcing. In order to cast the rock anchor 5, first, as shown in FIG. 1, at a position near the cliff surface 20, which is separated from the cliff surface 20 where the expected collapse range 20 p is located by a predetermined distance substantially L2, A shaft 3 having a diameter D1 is formed by digging down from the crown 2c into the bedrock 2 along the cliff surface 20 by a predetermined depth L1. At this time, in parallel with the excavation work, a head concrete 3b is poured into the top of the shaft 3 at the top of the shaft 3 and a rolled concrete 3a constituting the side wall of the shaft 3 is rolled up to a predetermined volume. It is cast together with the shoring and the lock bolt in the form of the thickness W1.

When the shaft 3 is excavated and formed in this way to support the shaft 3 through the rolled concrete 3a or the like, a scaffold (not shown) assembled when the shaft 3 is constructed in the shaft 3 is used. As shown in FIG. 11, the bore hole 22 is provided at the position where the lock anchor 5 is to be driven, and the length corresponding to the length L5 of the primary fixing portion 6b in the pilot portion 22a shown at the right end of FIG. The rock 2 is drilled so as to connect the shaft 3 and the cliff surface 20 so as to form a predetermined diameter D4 only in the portion and a predetermined diameter D3 slightly larger than the diameter D4 of the pilot portion 22a in other portions. By doing so, a penetration is formed. Thus borehole 2
2, the measuring device 25 is inserted into the borehole 22 in such a manner that the rod 26 is extended by an amount corresponding to the length of the borehole 22, and the limit switch 31 serving as the detection unit is inserted into the borehole 22. The information indicating whether or not the hole wall 22b is detected is output to the indicator lamp 28 as an output means, and the limit switch 31 is turned on.
The length of the rod 26 inserted into the borehole 22 is detected by determining whether or not the rod 26 is disposed inside, and the length of the borehole 22 is measured accordingly. Therefore, first, as shown in FIG.
The rod 26 is connected to the casing 30 disposed at the distal end thereof in an appropriate number, and then the
11 from the left to the right in FIG.
At this time, the measuring device 25 in which the lever 33 of the limit switch 31 housed in the casing 30 is in the released state in the hole wall detecting portion 25a before being inserted into the borehole 22, is moved from the opening window 30a to the roller 32. When the lever 33 is swingable in the directions of arrows C and D in FIG.
As shown in FIG. 12, the roller 32 abuts against the hole wall 22b of the bore hole 22 and is slightly inclined in the direction of arrow C so as to be restrained by the roller 32, as shown in FIG.
It is inserted while rolling along b. As the roller 32 rolls along the hole wall 22b of the borehole 22, the limit switch 31 detects the hole wall 22b, that is, in this state, the limit switch 31 assumes a load state, whereby the operating unit 35 The circuit for turning on the indicator lamp 28 is cut off while exhibiting the OFF state. Therefore, the worker who is performing the insertion work of the measuring device 25 in the form of extending the rod 26 in the shaft 3 visually observes the extinguishing state of the indicator light 28, and the limit switch 31 closes the hole wall 22b. It is possible to determine that the detection is being performed.
It can be detected that the hole wall detector 25a, which is the tip of the hole, is disposed in the borehole 22.

Accordingly, the rods 26 are extended in such a manner that the required number of rods 26 are connected and connected via the reducing nipples 27 and the like, and the hole wall detecting section 25a is pushed toward the cliff surface 20 side. As the work of inserting the measuring device 25 is continued,
Eventually, as shown in FIG. 13, the hole wall detecting portion 25 a protrudes toward the valley 21 from the cliff surface 20 outside the borehole 22. As a result, the limit switch 31 provided on the hole wall detection unit 25a is connected to the opening window 30a of the casing 30.
11 is released from the state in which it is restrained by the borehole hole wall 22b and tilted in the direction of arrow C as shown in FIG. 11, and the lever 33 pivots its swing axis as shown in FIG. Then, it is returned to the shape oriented in the vertical direction in FIG. By releasing the roller 32, the limit switch 31 detects that there is no hole wall 22b at a position corresponding to the roller 32, that is, the operation unit 35
Turns on and connects to the circuit. Then, the operating section 35 turns on the indicator lamp 28 as shown in FIG. Therefore, the operator who has performed the work of inserting the measuring device 25 into the borehole 22 can turn on the limit switch 31 by turning on the indicator lamp 28.
Does not detect the hole wall 22b, and thereby detects that the hole wall detection unit 25a is arranged to protrude toward the valley 21 side from the cliff surface 20 outside the bore hole 22.

Therefore, the operator during the measuring operation is required to
14 is temporarily stopped, and as shown in FIG. 14, the measuring device 25 is slightly pulled back from the borehole 25 toward the shaft 3. Is repeated two to three times. By repeating the operation of pulling out the measuring device 25 from the borehole 22 to the shaft 3 or pushing the measuring device 25 toward the valley 21, the roller 32 of the limit switch 31
3, a state of being restrained by the hole wall 22b of the borehole 22 and a state of being released from the cliff surface 20 toward the valley 21 in a manner swinging in the directions of the arrows C and D are repeated. Reference numeral 28 repeatedly turns on and off. Then, by turning on the indicator light 28, the worker performing the scale measurement in the shaft 3 accurately confirms that the roller 32 of the limit switch 31 is arranged at the position corresponding to the cliff surface 20 in the hole wall detection unit 25a. Therefore, when the roller 32 is accurately positioned at a position corresponding to the cliff surface 20, the length of the measuring device 25 inserted into the borehole 22 at that time is detected. , The length L4 of the borehole 22 is detected. That is, the measuring device 25
Since the distance L8 of the lever 33 from the base end of the casing 30 and the length L6 of each rod 26 in the hole wall detecting portion 25a are determined in advance, the operator can:
The extension length of the rod 26 inserted into the borehole 22 until the roller 32 detected via the indicator light 28 is located at the position corresponding to the cliff surface 20, that is, the number of connected rods, By measuring the length L9 (shown in FIG. 13), which is connected to the rearmost end of the hole 26 and protrudes into the shaft 3, the length L4 of the borehole 22 can be easily and accurately measured.
Can be detected. In order to perform the work of measuring the borehole 22 in this manner, the cliff surface 2 of the borehole 22 is used.
It is not necessary to visually check the penetrating portion at the end on the 0 side (the right end in FIG. 1) from the valley 21 side. For the inspection work, one person who inserts the inspection device 25 into the bore hole 22 is required. If the operator is located in the shaft 3, the measuring operation can be completed simply and accurately in a short time only in the shaft 3.

When the length L4 of the bore hole 22 has been accurately determined, the pilot cap 7 is attached to the end of the bore hole 22 as shown in FIG.
a, a predetermined number of anchor bodies 9 via spacers 11b, etc.
With several pipes 9 in cloth packers 10a, 10b
Then, the lock anchor 5 material assembled so as to cover the primary fixing portion 6b and the secondary fixing portion 6c is inserted into the borehole 22 from the shaft 3 side. At this time, the anchor body 6
Since it is a C steel stranded wire, it is sufficiently flexible in a state where one or several of them are combined, and therefore, some connecting members are necessary to form the length L3 of the anchor body 6. It is not necessary to connect the length L3 of the anchor body 6 to the accurately measured borehole 22 into which the anchor body 6 is to be inserted in an anchor assembling work space provided at the top 2c of the shaft 3 or the like. Is cut and assembled in a form corresponding to the length L4. Then, the lock anchor 5 material, which has been cut so that the anchor body 6 can have the predetermined length L3, is transferred to the borehole 22 already measured from the shaft 3 through the shaft 3, and the length of the borehole 22 is changed. Insert exactly L4 minutes. As a result, the material of the lock anchor 5 formed by the anchor body 6 is
As shown in the figure, the pilot cap 7 constituting the tip of the anchor body 6 is disposed slightly closer to the bedrock 2 than the cliff surface 20 at a position corresponding to the cliff surface 20, and the anchor head is later provided. The portion to be the portion 6a can be inserted and arranged at an appropriate position in the borehole 22 with the portion being left in the shaft 3. At this time, the cliff surface 20 has various undulations, and the cliff surface 20 may have collapsed after the anchor design, and when the bore hole 22 is formed, a slight bend may occur. From a certain point, it is conceivable that the designed borehole length and the length L4 of the borehole 22 actually formed are slightly different, but the length of the material of the lock anchor 5 inserted into the borehole 22 is as follows. As described above, the lock anchor material 5 is placed in the borehole 22 in a form exactly corresponding to the length of the borehole L4, which is accurately measured and measured through the measuring device 25 as described above. The pilot cap 7 and the portion that will later become the head 6a are accurately positioned by the length L4.

When the material of the lock anchor 5 constituted by the anchor body 6 is accurately inserted into the bore hole 22 by a predetermined length corresponding to the length L 4 of the bore hole 22, next, FIG. As described above, the cloth packer 1 has the opening ends 9a, 9a injecting and exhausting through the pipes 9, 9 arranged in the primary fixing section 6b.
An appropriate fixing material 16 such as mortar, cement milk, resin, or the like is injected into Oa. Then, the fixing material 16 injected into the cloth packer 10a is densely filled in such a manner that only the moisture in the fixing material 16 slightly escapes from the meshes of the aramid fibers constituting the cloth packer 10a. Go.
When the injection of the fixing material 16 into the cloth packer 10a is continued until the fixing material 16 is returned from the pipe 9 on the exhaust side, the fixing is performed by a predetermined length corresponding to the length L5 of the primary fixing portion 6b. In the form in which the material 16 is filled between the anchor body 6 and the bedrock 2, the lock anchor 5 has a tip portion which is provided around the pilot portion 22 a of the borehole 22 in FIG.
The shape is fixedly supported by the bedrock 2 in the region indicated by the 6 diagonal lines.

Then, next, in the shaft 3, the anchor 6
As shown in FIG. 3, an anchor head 15 is attached to a portion protruding into the shaft 3 through a taper washer 12 and a support base 13, and an anchor head 6a is assembled. As shown in FIG. 16, the anchor jack 6, the reaction table 19, and the like are mounted and assembled, and the anchor body 6 is tensioned by pulling the anchor jack 17 with a predetermined force F via the anchor jack 17. After performing the primary fixing and tensioning work in this manner, as shown in FIG. 17, the anchor head 15 is fixed, and then the open ends 9a, 9
a through the pipes 9, 9 a
Then, the fixing material 16 is injected into Ob. At this time, an appropriate gas body is supplied and injected into the free length portion 6d through a gas nozzle 6b that is open here, and the supplied injected gas is held at a predetermined pressure. Then, cloth packer 10
The fixing material 16a injected and filled in the b is sealed at the free length portion 6d by a gas having a predetermined pressure, and does not leak from the borehole 22 to the shaft 3 side through the free length portion 6d. In the next fixing portion 6b, the space between the anchor body 6 and the bedrock 2 is densely injected and filled. In this manner, when the secondary fixing portion 6c is fixedly formed by the predetermined length L10,
As shown by hatching in FIG. 17 together with the above-described primary fixing portion 6b, the lock anchor 5 is fixedly supported on the bedrock 2 substantially over its entire length in such a manner that only the free length portion 6d is left.

As described above, when the rock anchors 5 are successively hit and set in the boreholes 22 formed so as to connect the cliff surface 20 corresponding to the assumed collapse range 20p and the slab concrete 3a of the shaft 3, The bedrock 2 disposed between the cliff surface 20 and the rolled concrete 3a of the shaft 3 is reinforced by the anchor body 6 of the lock anchor 5 to be fastened along the length direction of the anchor body 6, respectively. Being
The rock mass 2 reinforced and fastened by the anchor body 6 of each of the lock anchors 5 is integrated into
The collapse of the entire bedrock 2 corresponding to 0p is prevented. At this time, each of the lock anchors 5 is arranged such that the pilot cap 7 which is the distal end of the anchor body 6 is disposed slightly closer to the rock 2 than the cliff 20 at a position corresponding to the cliff 20.
The pilot cap 7 protrudes from the cliff surface 20 to the valley 21 side from the place where the pilot cap 7 is fixed to the bedrock 2 in a state where the pilot cap 7 is inserted and disposed at an accurate position in each bore hole 22, and the landscape of the cliff surface 21 is damaged. Alternatively, there is no possibility that the injection of the fixing material 16 into the cloth packer 10a becomes defective and the formation of the primary fixing portion 6b becomes incomplete. At the same time, the insertion length of the anchor body 6 is shortened by disposing the pilot cap 7 farther from the cliff face 20 than the cliff face 20, whereby the rock 2 near the cliff face 20 remains without being anchored. The danger of being caught is also prevented. Therefore, as described above, after forming the borehole 22, the borehole 22 is measured using the measuring device 25, and the lock anchor is formed based on the measured actual borehole length L <b> 4. 5, the anchors 6 are set at the correct positions on the rock 2 by hitting and setting them, and a sufficient anchoring force set on the rock anchors 5 is developed. Is efficiently and reliably performed, thereby eliminating the risk of rock collapse from the expected collapse area 20p. The lock anchor 5
In order to construct the shaft, the shaft 3 is dug down, the borehole 22 is pierced, the borehole 22 is measured, and the anchor body 6 is inserted therein.
It is not necessary to carry out from the valley 21 side, and the ground collapse prevention construction can be performed with very high work efficiency on the mountain 1 side near the shaft 3, which is convenient.

In the above-described embodiment, the screw of the nipple 27 having the reduced diameter is used as a rod for extending the bore hole 22 in a shape corresponding to the length of the bore hole 22 in the measuring device 25 for measuring the bore hole 22. The example using the rod 26 connected through the shaft has been described.
It is sufficient that the rod 26 can be inserted into the borehole 22 from the side so as to be extended by an amount corresponding to the length of the borehole 22. Therefore, the rod 26 does not need to be constituted by the steel pipe member as described in the embodiment. It does not matter, for example, it may be made of a member having flexibility as long as the length of the borehole 22 can be detected. Also,
In the embodiment, as a detection unit for detecting the hole wall 22 b of the borehole 22, a roller lever-type contact type in which the lever 33 swings is provided to the hole wall detection unit 25 a, which is the tip of the measuring device 25. Although the example in which the limit switch 31 is provided in a form accommodated in the casing 30 has been described,
The configuration of the detection unit is not limited to this, and may be configured by another limit switch or a non-contact type detection unit. Similarly, the output means provided in the measuring device 25 has an indicator light of a form that can determine whether or not the limit switch 31 as the detecting unit is detecting the hole wall 22b by visually checking the lighting / off state. 2
The present invention is not limited to 8, and may be configured so that the detection of the hole wall 22b of the limit switch 31 can be determined based on other output modes. In the embodiment, the detection unit such as the limit switch 31 and the output unit such as the indicator lamp 28 are connected via the cable 29 that can transmit the electric signal S2. The output means may be connected via other wired or wireless means.

Further, in the above-described embodiment, the shaft 3 is excavated and formed along the cliff surface 20 in order to prevent the collapse of the cliff surface 20 in which the assumed collapse range 20p is arranged. The borehole 22 is formed through the borehole 22 so as to connect the upright concrete 3 a of the shaft 3 and the cliff surface 20.
In the embodiment 2, the lock anchor 5 is hit and set in such a manner that the anchor body 6 made of a PC steel strand or the like is inserted as an anchor member, but the gist of the present invention is to prevent the cliff surface 20 or the like from collapsing. Therefore, by inserting the anchor body 6 into the bore hole 22 penetrating from the construction site other than the cliff surface 20 such as the shaft 3, the lock can be performed without any work from the cliff surface 20 side such as the valley 21. In the embodiment, which is the distal end portion of the anchor 5, the anchor 5 is hit and set in such a manner that the pilot cap 7 is arranged at a position corresponding to the cliff surface 20, so that the rock mass 2 can be properly fastened and reinforced. Therefore, the configuration and form of the cliff surface 20, the shaft 3, the borehole 22, and the anchor body 6 inserted therein and the material constituting the lock anchor 5 other than the anchor body 6 to prevent the collapse, and The construction procedure is a configuration or procedure other than that described in the embodiment, and does not impose any problem.

[0024]

According to the present invention as described above, according to the present invention, where
It has a rod body such as a rod 26 that can be extended for each fixed length.
A hole wall detector 25a and a limit switch are provided at the tip end of the rod.
A detecting unit such as a switch 31; the detecting unit includes a roller 32;
Hole wall detecting means such as the lever 33, and the hole wall detecting means
An operation unit 35 that outputs a predetermined signal according to the hole wall detection state
Etc., and a signal from the signal output means.
Output means such as an indicator lamp 28 for performing a predetermined display according to the signal
Since a step is provided to form a borehole measuring device for a lock anchor such as the measuring device 25, the detection unit is configured to detect the borehole 22.
The output means outputs the information as to whether or not the hole wall 22b is detected, and determines whether or not the detection unit is disposed in the bore hole 22. Thus, the rod inserted into the bore hole 22 is determined. Detects the extension length of borehole 2
Two lengths can be measured. Therefore, for example, when measuring a borehole that is formed to penetrate a rock surface such as the cliff surface 20 to prevent collapse and a shaft such as the shaft 3, only from the shaft which is one end side of the borehole is measured. , Through which the rod can be extended and inserted into the borehole to perform a measuring operation.For the measuring operation, the rod projects from a penetrating portion corresponding to the rock surface at the other end of the borehole. Need not be visually checked on the rock face side. That is, one worker arranged in the shaft has an extension insertion work of the rod, and whether or not the detection unit is arranged in the borehole at the tip side of the rod, that is, the detection unit is out of the borehole. It is determined that the length of the rod at that time is detected, and the measuring operation can be performed easily and in a short time only from the shaft side without the need for multiple workers to communicate with each other. Can be done. And
For borehole inspection work, there is no work to visually check the tip of the measuring device at a position away from the rock face side, and the time when the extension length of the rod should be detected is determined by the machine of the output means. Can be detected based on typical output information, it is possible to detect a very accurate borehole length, and since no labor is required for the operator for the visual confirmation, the labor is locked. Efficient work can be performed by spending on anchor construction such as anchor assembly and loading preparation. Therefore, when the borehole measuring device for a rock anchor according to the present invention is used, the rock surface to be prevented from collapse is a steep cliff, and a work scaffold is assembled along the rock surface, or at a position facing the rock surface. Even if it is not possible to set up an observation point, or if there are restrictions on topography or climate, and it is difficult to work from the rock face due to the necessity of maintaining the landscape, The length of the borehole penetratingly formed by connecting the vertical shaft and the rock surface can be easily and accurately measured, so that the rock surface is undulated and the bore hole is drilled. It is very convenient to measure the length of the borehole, which causes a difference from the design value, and to perform accurate anchoring.

Further, a shaft 3 is dug down near the rock surface such as the cliff surface 20 to be prevented from collapsing along the rock surface, and the concrete 3a or the like of the shaft 3 is formed from the inside of the shaft 3. By drilling a hole in the rock 2 so as to connect the side wall of the rock and the rock surface, a bore hole 22 is formed to penetrate, and from the inside of the shaft 3 into the bore hole 22 formed through the hole,
The length of the borehole 22 is detected by inserting a borehole measuring device for a lock anchor such as the measuring device 25, and the borehole 22 detected through the borehole measuring device for the lock anchor is inserted into the borehole 22. By inserting an anchor member such as the anchor body 6 by a length corresponding to the length of the anchor member, the distal end portion of the pilot member 7 or the like of the anchor member is arranged in the bore hole 22 at a position corresponding to the rock surface. Since it was configured as
The anchor member inserted into the borehole 22 can fasten and reinforce the rock 2 disposed between the rock surface and the side wall of the shaft 3 in such a manner that the tip portion is arranged at a position corresponding to the rock surface. . Therefore, the anchor body is reliably positioned and cast into the borehole 22 accurately measured using the borehole measuring device for a lock anchor such that the tip end thereof is accurately positioned at a position corresponding to the rock surface. Therefore, due to an error in the measurement accuracy, the tip of the rock anchor is protrudingly arranged on the valley 41 side or the like outside the rock surface, and the landscape of the rock surface is deteriorated, or the lock anchor is positioned at the tip of the rock anchor. By not locating the rock at the position corresponding to the rock surface, there is no danger of impairing the anchor function, and the rock can always be properly tightened and reinforced to effectively prevent its collapse. At this time, any operation of confirming the tip of the measuring rod from the rock face side, which is usually considered necessary when measuring the borehole 22, is omitted, and the borehole 22 is used for the lock anchor. It is easily and accurately measured by the borehole measuring device. Therefore, when performing the rock anchor construction, the excavation formation of the shaft 3 and the borehole 22
, The length measurement of the bore hole 22 formed, and insertion of the anchor body 6 into the bore hole 22;
Can be performed from the mountain side where the shaft 3 is arranged, and no operation from the rock surface side is required. Therefore, since all of the anchor work can be performed concentrated in the vicinity of the shaft 3, the work efficiency is good, and the worker involved in the anchor construction does not need to be arranged on the rock surface side. Is located in a steep place facing the bedrock surface, so that it is not exposed to danger, the labor of the worker is concentrated and used effectively near the shaft 3, and furthermore, anchor work is performed on the bedrock side. Since there is no need to arrange the scaffolds and construction equipment, the landscape will not be impaired during construction. The anchor body thus inserted and cast into the rock 2 can be fixed in such a manner that its tip portion is slightly arranged on the rock side from the rock surface with the tip corresponding to the rock surface. It is possible to prevent the anchor head, which is indispensable to give tension to this, protruding to the rock surface side after construction and remaining there, thereby preventing the landscape on the rock surface side from becoming artificial I can do it. Therefore, if the necessity of maintaining a high landscape is required and the construction environment is severe, such as on steep slopes where the construction environment is severe, if the rock anchor construction method according to the present invention is performed,
Without performing anchoring in the form of driving from the cliff, a lock anchor is efficiently placed and set here in the form of being placed on the back side of the cliff to be prevented from collapsing. It is possible to obtain an appropriate rock-rock fastening reinforcement effect while maintaining the landscape on the cliff side, so that the effect can be used extremely effectively.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of a mountain to which a lock anchor construction method according to the present invention is applied.

FIG. 2 is a view taken in the direction of the arrow II in FIG.

FIG. 3 is a cross-sectional side view illustrating an example of a lock anchor that is cast on the mountain illustrated in FIG. 1;

FIG. 4 is a sectional view taken along arrows IV and IV in FIG.

FIG. 5 is a sectional view taken along arrows V and V in FIG. 3;

FIG. 6 is a view showing an example of a borehole measuring device for a lock anchor used in the lock anchor construction method shown in FIG. 1;

FIG. 7 is an enlarged sectional view showing a rod part in the borehole measuring device for a lock anchor shown in FIG. 6;

FIG. 8 is an enlarged side view showing a hole wall detection unit in the borehole measuring device for a lock anchor shown in FIG. 6;

FIG. 9 is a top view as viewed in the direction of the arrow IX in FIG. 8;

FIG. 10 is a perspective view showing an example of a limit switch applied to the borehole measuring device for a lock anchor shown in FIG. 6;

FIG. 11 is a series of drawings showing a construction procedure of a lock anchor construction method according to the present invention.

FIG. 12 is a series of drawings showing a construction procedure of a lock anchor construction method according to the present invention.

FIG. 13 is a series of drawings showing a construction procedure of a lock anchor construction method according to the present invention.

FIG. 14 is a series of drawings showing a construction procedure of a lock anchor construction method according to the present invention.

FIG. 15 is a series of drawings showing a construction procedure of a lock anchor construction method according to the present invention.

FIG. 16 is a series of drawings showing a construction procedure of a lock anchor construction method according to the present invention.

FIG. 17 is a series of drawings showing a construction procedure of a lock anchor construction method according to the present invention.

FIG. 18 is a diagram showing an example of a conventionally proposed lock anchor construction method.

[Explanation of symbols]

2 rock bed 20 rock bed surface (cliff surface) 22 borehole 22b perforated wall 3 shaft 3a side wall (rolled concrete) 5 rock anchor 6 anchor member (anchor body) 7 ... Tip (pilot cap) 25... Borehole measuring device for lock anchor (measuring device) 25 a Detecting unit (hole wall detecting unit) 26… Rod 28 (output lamp) 31 detection part (limit switch) 32 hole wall detection means (roller) 33 hole wall detection means (lever) 35 signal output means (operation part)

Claims (2)

(57) [Claims] 1. A rod which can be extended every predetermined length, and a detector is provided at a tip side of the rod. The detector comprises a hole wall detecting means and a hole wall of the hole wall detecting means.
Signal output means for outputting a predetermined signal according to the detection state
And performs a predetermined display in accordance with a signal from the signal output means.
And a borehole measuring device for a lock anchor which is provided with an output means . 2. A shaft is dug down near the rock surface to be prevented from collapsing along the rock surface, and a hole is formed in the rock from the inside of the shaft to connect the side wall of the shaft and the rock surface. A borehole is formed through the borehole, and the borehole measuring device for a lock anchor according to claim 1 is inserted into the borehole formed through the shaft from the inside of the shaft, and the length of the borehole is detected. By inserting an anchor member into the borehole by a length corresponding to the length of the borehole detected through the lock anchor borehole measuring device, the tip end of the anchor member is inserted into the rock surface at the borehole. Lock anchor construction method configured to be placed at the corresponding position.