KR102194811B1 - Methods for testing cutting performance of TBM and rock cutting tool for composite ground - Google Patents

Abstract

The present invention discloses a test method for measuring a deflection force received when a TBM disk cutter or a rock cutting tool cuts a composite ground. In addition, the present invention also discloses a method of manufacturing a specimen used in this test.

Description

[Methods for testing cutting performance of TBM and rock cutting tool for composite ground}

The present invention relates to a method for testing composite ground cutting performance of a rock cutting tool such as a TBM disk cutter, and more specifically, to a test method for measuring a deflection force received when the rock cutting tool cuts the composite ground.

In addition, the present invention also includes a method of manufacturing a specimen used in this test.

In general, TBM (Tunnel Boring Machine) is an equipment that crushes rock and excavates by rotating a cutter head equipped with a plurality of disk cutters.

When TBM excavates even rock mass, the disk cutter wears uniformly, but when excavating a composite ground consisting of two or more different strata, it is said that instantaneous distortion (distortion) is continuously generated at the strata boundary (stratified surface). There is a problem.

When such torsional stress is accumulated, torsional deformation occurs in the disk cutter and cutter box, and this torsional deformation impairs the alignment of the cutter vise, obstructing the rotation of the disk cutter and increasing the rotational resistance, resulting in uneven wear of the disk cutter. .

Fig. 1(a) shows a disc cutter with uniform wear, and Fig. 1(b) shows a disc cutter with uneven wear. When single wear of the disk cutter occurs, the wear of the cutter ring proceeds quickly, so the replacement cycle is accelerated, which is the main cause of delaying the air by increasing downtime.

It is estimated that the distortion scale and phenomenon of the disk cutter caused by such a deflection force causes construction problems at the construction site, but there has not been any experimental measurement or analysis to date.

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a test method for measuring deflection (torsion, distortion) generated when a rock cutting tool such as a TBM disk cutter cuts a composite ground. There is this.

Specifically, the present invention relates to a first cutting angle (α, an angle measured in a clockwise direction between an extension line in an instantaneous traveling direction of a disk cutter and a strata interface) and a second cutting angle (β, a strata boundary in the excavating direction of the disk cutter). The purpose of this study is to provide a test method for measuring deflection (torsion, distortion) caused by this tilt angle).

Another object of the present invention is to provide a method for preparing a specimen used in this test.

The test method according to the first embodiment of the present invention includes the steps of: (a1) preparing a specimen (1) modeling a composite ground consisting of two or more strata; (a2) fixing the specimen (1); And, (a3) cutting the specimen 1 using the linear cutting test apparatus 100, cutting the specimen 1 while moving the cutting tool in a direction crossing the interface of the two strata, and generated in the cutting tool It includes; measuring the deflection force. The step (a3) is performed a plurality of times while changing the angle α formed between the linear movement direction of the cutting tool and the interface.

When the cutting tool performs a reciprocating linear motion, the angle α may be set in a range of 0° to 90°.

When the cutting tool performs a reciprocating linear motion, but rotates the specimen 1 by 90° after linear cutting in step (a3), the angle α may be set in the range of 0° to 45°.

When the angle α is between 15° and 30°, the specimen 1 may be tested by removing debris from the first cut part, arranging it evenly, and moving the cutting tool in the same path as the initial cutting path. In addition, when the angle α is greater than or equal to 45°, the test may be performed while moving the cutting tool in a path spaced apart from the first cut part.

A test method according to a second embodiment of the present invention includes: (b1) preparing a specimen modeled of a composite ground consisting of two or more strata; (b2) fixing the specimen to a rotating test apparatus; And, (b3) cutting the specimen using a cutting tool while rotating the specimen by rotating the rotation test apparatus, and measuring a deflection force generated in the cutting tool according to the first cutting angle α. Here, the first cutting angle α is an angle measured in a clockwise direction between the boundary surface and the extension line in the instantaneous traveling direction of the disk cutter.

In the specimen, two portions having different strengths are in contact with each other at an interface, and the interface is perpendicular. In addition, in step (b1), a plurality of specimens having different positions of the boundary surfaces are prepared, and in step (b3), the deflection force according to the first cutting angle (α) is measured by testing with specimens having different positions of the boundary surfaces. do.

One of the two parts may be made of a low strength concrete composition and the other may be made of a high strength concrete composition.

A test method according to a third embodiment of the present invention includes the steps of: (c1) preparing a specimen modeled of a composite ground consisting of two or more strata; (c2) fixing the specimen to a rotating test apparatus; And, (c3) cutting the specimen using a cutting tool while rotating the specimen by rotating the rotation test apparatus, and measuring the deflection force of the cutting tool generated according to the first and second cutting angles (α) (β). Includes; The first cutting angle α is an angle measured in a clockwise direction between the boundary surface and the extension line in the instantaneous traveling direction of the disk cutter, and the second cutting angle β is an angle formed between the excavation direction of the cutting tool and the boundary surface. .

The specimen is divided into two parts by an inclined strata interface, and one of the two parts has weaker strength than the other part.

The rotation test apparatus, a drive motor 210; A rotation shaft 212 rotated by the drive motor 210; A specimen fixing portion 230 that is rotated by the rotation shaft 212 and fixes the specimen; And a tool fixing part 240 on which the cutting tool is installed.

A torque sensor 245 and a 3-axis load cell 246 for measuring a deflection force may be installed on the tool fixing part 240.

As an alternative to this, the tool fixing part 240 includes a horizontal bar 241 installed so that the cutting tool is rotatable; And, a vertical bar 243 extending vertically from the ends of the horizontal bar 241 on both sides of the cutting tool; including, a horizontal bar 241 and a vertical bar in a portion between the end of the horizontal bar 241 and the vertical bar 243 ( A one-axis load cell 244 may be installed in a direction perpendicular to 243). The deflection force can be calculated by multiplying the force measured by the uniaxial load cell 244 by the distance to the cutting tool.

Another aspect of the present invention, a method for producing a specimen, includes the steps of: (d1) cutting the formwork 300 at an angle to make the first and second formwork 310 and 320; (d2) installing each of the first and second formwork 310 and 320 so that the cut surfaces 330 are horizontal; And, (d3) filling one of the first and second formwork 310 and 320 by pouring low-strength concrete and pouring high-strength concrete to the other.

After the step (d3), the first and second formwork 310 and 320 are removed by demolding, and then the first specimen part made from the first formwork 310 and the second specimen part made from the second formwork 320 In contact with each other, it can be installed on the specimen fixing part 230.

In step (d1), the cutting angle of the formwork 300 is the second cutting angle β, and the second cutting angle β is the angle between the boundary surface of the two layers and the excavation direction of the cutting tool in the composite ground.

The present invention provides a test method for measuring a deflection force (torsion, distortion) generated when a rock cutting tool such as a TBM disk cutter cuts a composite ground.

Specifically, the test method according to the present invention includes a first cutting angle (α, an angle measured in a clockwise direction between an extension line in an instantaneous progress direction of a disk cutter and a strata interface) and a second cutting angle (β, disk cutter). It is possible to measure the deflection (torsion, distortion) that occurs depending on the angle at which the strata boundary is tilted in the direction of excavation of.

In addition, the present invention provides a method of manufacturing a specimen used in this test.

1(a) is a photograph showing a disk cutter with uniform wear, and FIG. 1(b) is a photograph showing a disk cutter with uneven wear.
2 shows a first cutting angle (α, an angle measured in a clockwise direction between an extension line in an instantaneous progress direction of a disk cutter and a strata interface) and a second cutting angle (β, disk) of a joint or stratified anisotropic rock mass. A drawing showing the angle at which the strata boundary is inclined in the direction of the cutter's excavation.
3 is a view showing a first cutting angle of a disk cutter in a composite ground consisting of two layers.
FIG. 4 is a graph showing a distortion (torque stress) according to a ratio (A/R) of a distance A and a tunnel radius R between a horizontal line passing through the center of a tunnel and a strata interface.
5 is a front view showing the configuration of a linear cutting test apparatus.
6 is a view showing a specimen representing a composite ground and a disk cutter for cutting the specimen.
7 is a view showing an angle (α, a first cutting angle) formed between a moving direction of a disk cutter cutting a specimen and a strata interface.
8 is a graph showing a deflection force (deflection moment) according to a first cutting angle α.
9 is a view showing that the specimen of FIG. 7 is rotated by 90° in a counterclockwise direction.
10 is a view showing a cutting test method when the first cutting angle α is 15° to 30°.
11 is a view showing a cutting test method when the first cutting angle α is 45° or more.
12 is a view showing an example of a test apparatus having a vertical axis rotation method.
13 is a view showing a torque sensor for measuring a deflection force in the test apparatus of FIG. 12;
14 is a view showing a uniaxial load cell for measuring a deflection force in the test apparatus of FIG. 12;
15 is a perspective view showing a cylindrical specimen showing a composite ground.
16 is a view showing a first cutting angle α of a rock cutting tool (disk cutter, etc.) in the specimen of FIG. 15;
17 is a graph showing the relationship between A/R and a first cutting angle α.
18A is a perspective view showing a specimen for examining the effect of the first and second cutting angles α and β on the deflection force of the disk cutter.
18B is a longitudinal sectional view showing the specimen of FIG. 18A.
Fig. 19A is a cross-sectional view of Fig. 18A.
Figure 19b is a cross-sectional view of Figure 18a ②.
Fig. 19C is a sectional view taken by ③ of Fig. 18A.
20 is a graph showing the relationship between A/R and a first cutting angle α.
Fig. 21 is a view showing cutting a cylindrical formwork to fabricate the specimen of Fig. 18a.
Fig. 22 is a view showing that a half formwork made by cutting the cylindrical formwork of Fig. 21 is installed on a pedestal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only examples of the present invention, and do not represent all the technical spirit of the present invention, and various equivalents that can replace them at the time of application And it should be understood that there may be variations.

On the other hand, below will be described by taking as an example the application of the present invention to a composite ground consisting of two layers. Applying the present invention to a composite ground consisting of three or more strata will be readily apparent to those skilled in the art with reference to the present specification.

[Definition of anisotropic angle]

FIG. 2 shows a first cutting angle α and a second cutting angle β of anisotropic rock mass (joint or stratified rock mass).

The first cutting angle α is an angle formed between an instantaneous cutting direction of the disk cutter and a strata boundary, and is defined as an angle measured in a clockwise direction between an extension line and a boundary surface in the instantaneous moving direction of the disk cutter. In addition, the second cutting angle β represents the angle at which the strata boundary is inclined in the excavation direction (z direction) of the disk cutter. The first and second embodiments below are for a test method for measuring the deflection force according to the first cutting angle α, and the third exemplary embodiment is the deflection force according to the first and second cutting angles α and β. It is about a test method for measuring.

[Deflection moment]

3 shows a first cutting angle of a disk cutter in a composite ground consisting of two layers. In addition, FIG. 4 is a graph showing a distortion, torque stress according to a ratio (A/R) of a distance A and a tunnel radius R between a horizontal line passing through the center of a tunnel and a strata interface.

For convenience of explanation, it is assumed that the stratum consists of two rock masses, and the stratum below the stratum boundary is called the hard rock layer and the stratum above the stratum boundary is the soft rock layer. However, the first cutting angle α and the deflection force vary depending on the height at which the stratum boundary is located on the tunnel face. For example, if the radius of the tunnel is R and the distance between the horizontal line passing through the center of the tunnel and the strata boundary is A, the first of the outermost disk cutter (gauge disk cutter) increases as the ratio (A/R) increases. The cutting angle α increases, and accordingly, the distortion moment acting on the disk cutter increases, and then decreases from approximately A/R=0.8 to near zero when A/R=1.0.

In addition, as shown in FIG. 3, when the stratum boundary is located above the center of the tunnel when the TBM rotates in a counterclockwise direction, an instantaneous distortion continuously occurs in the clockwise direction when the disk cutter enters the soft rock layer. On the other hand, when the TBM rotates counterclockwise, if the strata boundary is located below the center of the tunnel, when the disk cutter enters the soft rock layer, instantaneous distortion continues to occur in the counterclockwise direction. That is, if the strata boundary is above the center of the tunnel, a deflection moment occurs in the clockwise direction, and if it is below the center of the tunnel, a deflection moment occurs in a counterclockwise direction.

When such asymmetrical stress is accumulated, torsional deformation is also caused in the disk cutter and the cutter box. This torsional deformation impairs the alignment of the cutter vise, hinders rotation of the disk cutter, increases rotational resistance, and consequently causes uneven wear of the cutter. If the cutter's single wear occurs, the cutter ring wears quickly, so the replacement cycle is fast. This is a major cause of delays by increasing downtime.

[Range of vertical force, rotational force and side force of disk cutter]

The rotational force (cutting force) of large rotary tools such as disk cutters is about 10-20% of the normal force. For 17 inches, the vertical force ranges from 2 to 30 tons, and the rotational force ranges from 0.2 to 5 tons. On the other hand, the maximum pressure load of the small wear tester according to the present invention is in the range of 2 to 3 tons. Therefore, it can only be used for testing disc cutters of 4 to 5 inches or less. Currently, the main type of disk cutter is 15 to 21 inches, so the capacity is insufficient for the wear test of large tools.

Therefore, it should be approached with the concept of a reduced model test. Since the maximum capacity of the 17-inch (432 mm) disk cutter is 50 tons, the wear test is possible only when the usable capacity is reduced to about 1/20 based on 17 inches.

On the other hand, in general isotropic rock cutting conditions, the lateral force (force acting in the lateral direction) of the disk cutter is usually measured within 1 to 5% of the normal force. So, you can usually ignore the influence of lateral forces on the disk cutter and binder assembly. However, when excavating anisotropic rock or composite ground, the lateral force may act more than 10-20% of the normal force when crossing the boundary between the joint and the bed. This lateral force, as described above, causes a problem in that the rotational axis of the disk cutter is deflected because it receives continuous distortion in a specific rotational direction, and as a result, the disk is not rotated. A disk cutter that rotates well causes constant wear only on the cutter ring, but a disk cutter that does not rotate causes uneven wear, which increases the TBM torque to decrease the cutting efficiency and shortens the cutter life to increase downtime. Has a very bad effect on TBM operation.

[First embodiment]

5 is a front view showing the configuration of a linear cutting test apparatus. And, Figure 6 is a view showing a specimen and a disk cutter showing the composite ground.

As shown in the figure, the linear cutting test apparatus 100 includes a disk cutter 10, a first unit for moving the disk cutter 10 in the z direction, and a second unit for moving the specimen 10 in the x direction. And, it includes a third unit for moving the specimen 10 in the y direction.

The disk cutter 10 is rotatably installed on the tool fixing part 140 (saddle). A torque sensor 145 and a three-axis load cell 146 are installed on the tool fixing part 140. The torque sensor 145 measures the deflection force (moment to rotate around the z-axis, Mz), and the three-axis load cell 146 measures the load in the three-axis directions (x, y, and z-axis directions).

The first unit lifts the disk cutter 10 in the z-axis direction. The first unit includes an elevating cylinder 110, and the elevating cylinder 110 is installed on the upper frame 112 to elevate the disk cutter 10 in the z-axis direction.

The second unit moves the specimen 1 in the ±x direction. The second unit is installed on the bogie 135 which is linearly moved in the ±y direction. The second unit includes a first cylinder 120 and a specimen fixing part 125. The specimen fixing part 125 is linearly moved in the ±x direction by the elongation and contraction of the first cylinder 120.

It is preferable that the specimen fixing part 125 is square and can be rotated by 90° automatically or manually, and can be moved in the ±x direction by the first cylinder 120 after being rotated by 90°. This will be described later.

In addition, the third unit includes a second cylinder and a bogie 135 that is moved in the ±y direction by the second cylinder. Due to the extension and contraction of the second cylinder, the bogie 135 is moved along the rail 136 in the ±y direction.

As shown in FIG. 7, if the angle (first cutting angle) formed by the moving direction of the disk cutter 10 and the strata interface is α ₁ , the first cutting angle α ₁ is 0° to 180° or- It has a value from 90° to +90°. At this time, since the disk cutter 10 can linearly reciprocate in both directions, the first cutting angle α ₁ may be set to 0° to 90° when the specimen is manufactured.

8 is a graph showing the magnitude of a deflection moment according to a first cutting angle α. As shown in FIG. 8, it is estimated that the maximum deflection moment occurs when α=±10 to 30°.

Meanwhile, FIG. 9 is a view showing that the specimen of FIG. 7 is rotated by 90° in a counterclockwise direction. First cutting angle (α _'1) in Fig. 9 and α ₁ satisfies the equation 1 below.

[Equation 1]

_{α '1 = 90 ° - α} 1

When the disk cutter 10 moves upward, the first cutting angle is α ₂ , and when moving downward, the first cutting angle is α ₁ (α ₂ =180°-α ₁ ), as shown in FIG. Since this is a square, if the specimen can be rotated 90°, the specimen can be manufactured so that the first cutting angle (α ₁ ) is 0° to 45°. Here, assuming that no deflection moment occurs at 0° and 90°, three specimens at 15° intervals, that is, specimens with a first cutting angle of 15°, 30°, and 45°, are sufficient to measure the deflection force. Do.

Meanwhile, FIG. 10 shows a cutting test method when the first cutting angle α is in a small angle range, for example, when the first cutting angle α is 15° to 30°. When the first cutting angle α is a small angle, e.g., 15° to 30°, the cutting range at the time of the first cutting (e.g., downward cutting) can occupy most of the strata boundary, so additional cutting tests are performed. A problem arises that is difficult to test to penetrate the strata interface. As shown in FIG. 10, when the specimen is 1m×1m, the first cutting angle (α) is 15°, and the cutting depth (d) is 4mm, the crushing range of one side of the disk cutter 10 is about 50mm, About half of them fall into the crushing range, and as a result, the additional cutting line is pushed out of the strata boundary.

In this case, it is possible to pre-condition the entire surface of the specimen to remove debris from the cutting surface and arrange it evenly, and then perform a reciprocating cutting test (for example, an upward cutting) at the same spot as the first cutting trajectory ①.

On the other hand, as shown in FIG. 11, when the first cutting angle α is a large angle, for example, 45° or more, the trajectories ①, ②, and ③ can be sufficiently separated and tested in different cutting directions. In other words, it can be tested like No. ① upward, No. ② downward, and No. ③ upward.

[Second Example]

12 is a view showing an example of a test apparatus having a vertical axis rotation method.

The test apparatus 200 includes a driving motor 210, a rotating shaft 212 rotated by the driving motor 210, a specimen fixing part 230 rotated by the rotating shaft 212, and a cutting tool 10 It includes a linear movement unit for linearly moving. A gear assembly for adjusting the rotational speed R.P.M. may be included between the driving motor 210 and the rotational shaft 212.

The linear moving unit includes a frame 250, a support 252, and a rail. The frame 250 is installed to be slidable along the rail. Inside the frame 250, a torque sensor (245 in FIG. 13) and a three-axis load cell 246 are installed.

The sliding may be performed by a moving motor (not shown in the drawing). The rail is installed on the lower surface of the support 252 along the x direction. Therefore, when the moving motor is operated, the frame 250 slides along the rail in the ±x direction.

The disk cutter 10 cuts the rock specimen 1 while the specimen 1 is rotated around the rotation shaft 112 by the driving motor 110, and when the cutting is completed, the moving motor operates to operate the disk. The cutter 10 is moved in the ±x direction, and when the movement of the disk cutter 10 is completed, the specimen 1 is rotated around the rotation shaft 112 by the drive motor 110, and the disk cutter ( 10) Cut the rock specimen (1).

As shown in FIG. 13, a torque sensor 245 is installed on the tool fixing part 240, and a three-axis load cell 246 is installed on the torque sensor 245. The tool fixing part 240 rotatably fixes the disk cutter 10, the torque sensor 245 measures a deflection force (deflection moment, Mz), and the three-axis load cell 246 is x, y, z axis Measure the force of the direction. Meanwhile, in the drawings, the disk cutter 10 is shown as being installed on the tool fixing part 240, but other rock cutting tools may be installed in place of the disk cutter 10.

Meanwhile, FIG. 14 shows another method for measuring a deflection force (deflection moment, Mz). A uniaxial load cell 244 is provided between the end of the horizontal bar 241 and the vertical bar 243 penetrating the left and right sides of the disk cutter 10 (rock cutting tool). Since the uniaxial load cell 244 can only measure the compressive load, two uniaxial load cells 244 are mounted in the same direction (y-axis direction) to measure the deflection force in the clockwise and counterclockwise directions. The deflection force (deflection moment, Mz) is calculated by multiplying the measured deflection force by the distance (d) between the center of the disk cutter.

(1) Cutting speed of TBM disc cutter

The TBM disk cutter 10 has all different linear speeds depending on the radius at which it is located. The moving speed of the gauge disk cutter 10 located in the outermost part is the fastest and wear is the fastest. Therefore, in order to perform the wear test according to the moving distance, it must be possible to implement everything from the speed of the fastest gauge disk cutter 10 to the speed of the disk cutter 10 located at the center.

In general, the R.P.M. of the TBM disk cutter head ranges from 2 to 6. Therefore, assuming that the diameter of TBM for railroad tunnel is 8m, the range of line speed is calculated by Equation 2 below.

[Equation 2]

Calculating the linear speed of the gauge disk cutter 10 according to the number of rotations and diameter of TBM is as shown in Table 1 below. Since the number of rotations decreases as the diameter of TBM increases, the moving speed of the gauge disk cutter 10 is approximately 0.5. It is calculated to have a range between ~2.5 m/s. (Applicable figures are indicated in blue in Table 1)

[Table 1] Linear speed of gauge disc cutter according to TBM rotation speed (R.P.M.)

(2) Proper R.P.M. calculation method: linear velocity conversion

When the radius of the specimen (1) is 0.3 m, the R.P.M. of the specimen compared to the linear velocity of the TBM disk cutter was calculated. The range was investigated from 15 to 60 R.P.M., and 127 R.P.M. was calculated as needed if the specimen radius was 0.15 m. The range of 15~120 R.P.M. can be realized by a combination of a motor and a reducer.

[Table 2] Investigation of rotational speed range of rock specimen

(3) Pick's horizontal feed speed

The pick's radial feed rate is relatively slow compared to R.P.M. When the specimen rotation is 120 R.P.M., a maximum radial feed rate of 10 mm/s is sufficient.

(4) Method of measuring the deflection force according to the first cutting angle (α)

A method of measuring the deflection force according to the first cutting angle α using the test apparatus 200 will be described. Hereinafter, for convenience of explanation, a gauge disk cutter 10 (the outermost disk cutter) will be described as an example. 15 is a perspective view showing a cylindrical specimen representing a composite ground, which is installed on the specimen fixing portion 230 of the testing apparatus 200.

Specimen (1) represents a composite ground consisting of soft rock and ordinary rock. The strata interface of the two strata (soft rock and ordinary rock) is formed vertically. Accordingly, when the specimen 1 is installed on the specimen fixing part 230, the boundary surface (layered surface) is vertical and the deflection force according to the first cutting angle α is applied without the influence of the second cutting angle β. Can be measured.

In this test method, the location of the interface is expressed as the distance (A) from the horizontal line passing through the center of the specimen (the center of the tunnel). As shown in Figs. 16-17, if the radius of the specimen (the radius of the tunnel or the radius at which the disk cutter rotates) is R, the first cutting angle (α _up , the entry angle of the disk cutter) when A/R = -1 ) Becomes the minimum (0°), and when A/R=1, the first cutting angle α _up becomes the maximum (180°).

[Third Example]

18A is a perspective view showing a specimen for examining the effect of the first and second cutting angles α and β on the deflection force of the disk cutter, and FIG. 18B is a longitudinal sectional view showing the specimen.

The specimen is a model of a composite ground consisting of two layers. The two strata are, for example, soft rock and ordinary rock, respectively, and the boundary surface (stratified surface) of the two strata forms a second cutting angle β with respect to the excavation direction (vertical line) of the cutting tool.

When the cutting tool 10 cuts the section ①, as shown in FIG. 19A, the distance (A) between the stratum boundary and the center line of the specimen is long, and when the cutting tool 10 cuts the section ②, as shown in FIG. 19B. As such, the strata interface coincides with the center line of the specimen, and when the cutting tool 10 cuts the section ③, the distance (A) between the strata interface and the center line of the specimen increases again as shown in FIG. 19C.

And, Fig. 20 shows the relationship between A/R and the first cutting angle α. When the cutting tool 10 cuts ① the cross section, the first cutting angle α is close to 90°, and when the cutting tool 10 cuts ② the cross section, the first cutting angle α is 0°. When the cutting tool 10 cuts the section ③, the first cutting angle α approaches 90°.

As above, if the specimen is used, all stratum interfaces according to the stratum division ratio can be implemented with one cutting test. Therefore, it is possible to implement all of the first cutting angle α from -90° to +90°.

[How to make a specimen]

FIG. 21 is a view showing cutting of a cylindrical formwork to produce the specimen of FIG. 18A, and FIG. 22 is a view showing that the half formwork (first and second formwork) made by cutting the cylindrical formwork is installed on a pedestal.

As shown in the drawing, the first and second formwork 310 and 320 are made by cutting the cylindrical formwork 300 to be inclined, and then the cut surfaces 330 of the first and second formwork 310 and 320 are horizontally It is supported by the pedestal 340 so that it is installed and then cured by pouring concrete into the first and second forms 310 and 320, respectively.

The cutting angle of the cylindrical formwork 300 is a second cutting angle (β), and as described above, the second cutting angle (β) refers to the angle between the boundary surface of the two layers and the excavation direction of the cutting tool in the composite ground. .

Concrete or concrete mortar expressing different strengths is poured into the first and second formwork 310 and 320. For example, concrete expressing hard rock strength may be poured in the first formwork 310, and concrete expressing soft rock strength may be poured in the second formwork 320.

Then, when the poured concrete is cured, the first formwork 310 is demolded (removed) to complete the first specimen part, and the second formwork 320 is demolded (removed) to complete the second test piece part. Next, the first and second specimens are stacked so that the cut surfaces of the specimens are in contact with each other, and the outer circumferential surfaces of the first and second specimens are fixed with a jig (not shown in the drawings), etc.

1: specimen 10: cutting tool (TBM disk cutter)
100: linear cutting test device
110: lifting cylinder 112: upper frame
120: first cylinder 125: specimen fixing portion
135: bogie 136: rail
145: torque sensor 146: 3-axis load cell
200: vertical axis rotation type test device 210: drive motor
212: rotation shaft 230: specimen fixing part
240: tool fixing part 241: horizontal bar
243: vertical bar 244: 1-axis load cell
245: torque sensor 246: 3-axis load cell
250: frame 252: support
α: 1st cutting angle β: 2nd cutting angle
A: Distance between the horizontal line passing through the center of the tunnel (or the center of the cutting track of the cutting tool) and the strata boundary
R: Radius of tunnel (radius of cutting track of cutting tool)

Claims (14)

(a1) preparing a specimen modeling a composite ground consisting of two or more strata;
(a2) fixing the specimen; And,
(a3) cutting the specimen by using a linear cutting test apparatus, cutting the specimen while moving the cutting tool in a direction crossing the interface of the two strata, and measuring a deflection force generated in the cutting tool; and ,
The step (a3) is a test method, characterized in that a plurality of times while changing the angle (α) formed by the linear movement direction of the cutting tool and the interface. The method of claim 1,
The test method, characterized in that the cutting tool makes a reciprocating linear motion and the angle (α) is set in the range of 0° to 90°. The method of claim 1,
The cutting tool performs a reciprocating linear motion, wherein step (a3) further includes rotating the specimen by 90° after the linear cutting, and the angle α is 0° to 45°. The method according to claim 1 or 2,
If the angle (α) is 15° to 30°, after removing debris from the first cut part of the specimen and arranging it evenly, test by moving the cutting tool in the same path as the original cutting path,
When the angle (α) is 45° or more, the test method is characterized in that the test is performed while moving the cutting tool in a path spaced apart from the first cut part by a predetermined distance. (b1) preparing a specimen modeling a composite ground consisting of two or more strata;
(b2) fixing the specimen to a rotating test apparatus; And,
(b3) cutting the specimen using a cutting tool while rotating the specimen by rotating the rotation testing device, and measuring a deflection force generated in the cutting tool according to the first cutting angle (α); Including,
The first cutting angle α is an angle measured in a clockwise direction between an extension line in an instantaneous traveling direction of the disk cutter and a strata interface. The method of claim 5,
In the specimen, two portions having different strengths are in contact with each other at an interface, and the interface is vertical,
In the step (b1), a plurality of specimens having different positions of the boundary surfaces are prepared,
The step (b3) is a test method, characterized in that the deflection force according to the first cutting angle (α) is measured by testing specimens having different positions of the interface. The method of claim 6,
A test method, characterized in that one of the two parts is made of a low strength concrete composition and the other is made of a high strength concrete composition. (c1) preparing a specimen modeling a composite ground consisting of two or more strata;
(c2) fixing the specimen to a rotating test apparatus; And,
(c3) cutting the specimen using a cutting tool while rotating the specimen by rotating the rotation test apparatus, and measuring the deflection force of the cutting tool generated according to the first and second cutting angles (α) (β); Including,
The first cutting angle (α) is an angle measured in a clockwise direction between the extension line in the instantaneous progress direction of the disk cutter and the strata interface, and the second cutting angle (β) is the angle between the excavation direction of the cutting tool and the interface Test method, characterized in that. The method of claim 8,
The test method, characterized in that the specimen is divided into two parts by an inclined strata interface, and one of the two parts has weaker strength than the other part. The method according to any one of claims 5 to 9,
The test device,
Driving motor 210;
A rotation shaft 212 rotated by the drive motor 210;
A specimen fixing portion 230 that is rotated by the rotation shaft 212 and fixes the specimen; And,
Includes; a tool fixing part 240 on which the cutting tool is installed,
A test method, characterized in that a torque sensor 245 and a three-axis load cell 246 for measuring the deflection force are installed on the tool fixing part 240. The method according to any one of claims 5 to 9,
The test device,
Driving motor 210;
A rotation shaft 212 rotated by the drive motor 210;
A specimen fixing portion 230 that is rotated by the rotation shaft 212 and fixes the specimen; And,
Includes; a tool fixing part 240 on which the cutting tool is installed,
The tool fixing part 240,
A horizontal bar 241 installed so that the cutting tool is rotatable; And,
Including; vertical bars 243 extending vertically from the ends of the horizontal bars 241 on both sides of the cutting tool,
A test method, characterized in that the uniaxial load cell 244 is installed in a direction perpendicular to the horizontal bar 241 and the vertical bar 243 at a portion between the end of the horizontal bar 241 and the vertical bar 243. delete delete delete

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