JPH07159146A - Displacement measurement of discontinuous surface and discontinuous surface displacement gage - Google Patents

Abstract

PURPOSE:To provide a displacement measuring method for a discontinuous surface in which the evaluation of the three-dimensional behavior of the ground can be carried out easily and the effective evaluation for the deformation of the ground with high precision is made possible by specifically measuring the displacement of the discontinuous surface occupying almost all the parts of the deformation of the ground, and to provide a discontinuous surface displace ment gage. CONSTITUTION:The discontinuous surface displacement gage 10 is equipped with a measurement part 14 having three surfaces 19 which cross at right angles and is installed in one baserock 12 on the one side of a discontinuous surface 11 in a pit well 13, and a sensor part 15 which is installed in another baserock 12 on the other side of the discontinuous surface 11 and is equipped with a displacement sensor 26 in three-axis directions opposed to each of three surfaces 19 crossing at right angles in the measurement part 14. The three-dimensional displacement of the discontinuous surface 11 is measured by measuring each displacement of three surfaces 19 crossing at right angles by each displacement sensor 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discontinuity surface displacement measuring method and a discontinuity surface displacement meter, and more particularly to measuring the displacement of a discontinuity surface such as a crack surface or natural joint in rock mass. The present invention relates to a discontinuous surface displacement measuring method and a discontinuous surface displacement meter.

[0002]

2. Description of the Related Art Conventionally, in the field of civil engineering / mining science or in the field of geophysics, displacement measurement of the ground such as rock is performed in order to properly evaluate the behavior of rock and the crust. There is. Then, as a method of measuring the displacement of the ground, generally, an extensometer is used. That is, this method provides a fixed measuring point in a well bored in the ground such as rock, and measures the change in the distance between this fixed measuring point and the measuring point provided at the mouth of the hole by using an extensometer. , To analyze the displacement of the ground.

[0003]

However, in the above-mentioned measuring method using the extensometer, the relative displacement along the borehole axis between two measuring points is only one-dimensionally grasped and evaluated. In order to evaluate the deformation of a rock three-dimensionally, it is necessary to provide a multiplicity of wells developed in a three-dimensional manner to measure multi-axis multi-points. The behavior of discontinuous surfaces such as crack surfaces and natural joints cannot be detected quickly.

That is, the conventional method has a problem in that a huge amount of experimental work is required in order to evaluate the three-dimensional behavior of the ground, since multi-axis multi-point measurement is required. The method of does not specify the discontinuity surface and analyze its behavior, but comprehensively summarizes the deformation of the discontinuity surface and the deformation of the ground that is a continuum with the change of the stress state in the ground. Since it is an evaluation, it is difficult to identify and evaluate the deformation of the discontinuous surface that controls most of the ground deformation, and the relationship between the behavior of the whole ground and the behavior of the discontinuous surface and the deformation direction. However, there is a problem that the amount of deformation cannot be accurately evaluated.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and it is possible to easily evaluate the three-dimensional behavior of the ground and to control most of the ground deformation. An object of the present invention is to provide a displacement measuring method for a discontinuous surface that enables highly accurate and effective evaluation of ground deformation by measuring the deformation of a continuous surface and a discontinuous surface displacement meter used for the measuring method. To do.

[0006]

The present invention has been made to achieve the above object, and its gist is a method for measuring the displacement of a discontinuous surface such as a crack surface in rock mass. , A borehole is bored across the discontinuous surface, and a measuring unit having at least three surfaces intersecting each other is installed on one side of the discontinuous surface in the borehole, and the other side of the discontinuous surface is sandwiched. A sensor unit having at least three axial displacement sensors facing the at least three surfaces of the measuring unit, and measuring the displacements of at least three surfaces intersecting with each other by the respective displacement sensors to obtain the discontinuous surface. It is a method of measuring the displacement of a discontinuous surface, which is characterized by measuring the three-dimensional displacement of.

Further, according to the displacement measuring method of the discontinuous surface of the present invention, when the measuring portion and the sensor portion are installed with the discontinuous surface in the borehole interposed, the measuring portion and the sensor portion can be detached in advance. A fixed guide member integrally with the fixed guide member, and the measuring unit and the sensor unit that are integrated by the fixed guide member are inserted into the well and moved to a measuring position where the discontinuous surface is sandwiched between the measuring unit and the sensor unit. It is preferable to install the measurement unit and the sensor unit in the borehole by removing the fixed guide member after fixing each in the borehole.

Another aspect of the present invention is a discontinuous surface displacement gauge for measuring the displacement of a discontinuous surface such as a crack surface in a rock mass, which is a first cylindrical member having one end. And a measuring section having a fixing means that has at least three surfaces intersecting with each other, and that is moved forward and backward in at least two directions outwardly in the radial direction of the tubular member by expansion and contraction means such as a hydraulic cylinder and a spring, Is a second tubular member continuous with at least three faces of the measuring unit, and at least one of the differentials in at least three axial directions is arranged to face the at least three faces at the end opposite to the one end. A sensor unit having a transformer displacement sensor and a fixing unit capable of advancing and retracting in at least two directions outward in the radial direction of the tubular member by an expanding and contracting unit such as a hydraulic cylinder and a spring; The member has a locking hole that locks with each fixing unit of the measuring unit and the sensor unit, and each fixing unit of the measuring unit and the sensor unit projects and locks with each locking hole, The discontinuity surface displacement meter comprises a fixed guide member that integrally fixes the measuring unit and the sensor unit.

In the discontinuous surface displacement meter of the present invention, it is preferable that the fixed guide member includes a borehole television for visually confirming the discontinuous surface.

Further, in the discontinuous surface displacement meter of the present invention, it is preferable that the fixed guide member includes a wheel type centrizer.

Further, in the discontinuous surface displacement meter of the present invention, the differential transformer displacement sensor includes an amplifier of the differential transformer displacement sensor, an AD converter, a CPU for measurement control and data / file management, and a data recording. It can also be connected to a memory.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of a discontinuous surface displacement meter 10 used in the displacement measuring method according to this embodiment for measuring the displacement of a crack surface in rock as an example of the discontinuous surface. The continuous surface displacement meter 10 mainly includes a measuring unit 14 installed in one rock bed 12 sandwiching the crack surface 11 in a well 13 formed by drilling in the rock bed 12 across the crack surface 11. The other bedrock 1 sandwiching the crack surface 11
A sensor unit 15 installed in the second unit subsequent to the measuring unit 14
And a fixed guide member 16 detachably attached along the outer side surfaces of the measuring unit 14 and the sensor unit 15.

As shown in the enlarged view of FIG. 2, the measuring unit 14 is composed of a measuring unit main body 17 as a first cylindrical member whose front end is reduced in diameter. Is
A three-sided surface 19 including a flat rear end surface 19a and two surface members 19b (one surface member 19b is not shown) intersecting at right angles to each other and extending and fixed from the rear end surface 19a in the rear vertical direction thereof. It is provided. Also, the measuring unit body 1
7 comprises a fixed rod 20 transverse to its radial direction. This fixed rod 20 has, for example, an expansion / contraction device in which a hydraulic cylinder and a spring are combined, and is provided at both ends of the fixed rod 20 by the hydraulic pressure supplied and controlled from the work base of the hole opening through the pressure line 21. The fixing pin 22 and the hole wall crimping portion 23 are moved back and forth in two radial directions facing each other while interlocking with each other. That is, for example, when the hydraulic pressure is applied, the fixing pin 22 is projected and the hole wall crimping portion 23 is retracted, and when the hydraulic pressure is removed, the fixing pin 22 is retracted and the hole wall crimping portion 23 is projected.

On the other hand, the sensor unit 15 is a sensor unit body 2 as a second tubular member following the tubular measuring unit body 17.
4 at the front end portion 25, that is, at the end portion on the side facing the rear end portion 18 of the measuring portion main body 17 provided with the three surfaces 19 in the three axial directions vertically facing the respective three surfaces 19. The three provided differential transformer displacement sensors (hereinafter referred to as “LVDT displacement sensors”) 26 are provided on the support base 2.
It is attached in each direction via 7. Further, the sensor section main body 24, similarly to the measurement section main body 17, is provided with the fixed rod 20 which traverses the radial direction of the sensor section main body 17 and has the same configuration as that described above. A membrane 28 as a waterproof seal member is attached to the gap between the measurement unit body 17 and the sensor unit body 24 where the three-sided surface 19 and the LVDT displacement sensor 26 are arranged. 19 and the LVDT displacement sensor 26 are protected. Also,
The LVDT displacement sensor 26 is a known one, and for example, as shown in FIG. 3, a differential transformer section 30 based on a primary coil 31, a secondary coil 32 and a core 33 made of a magnetic material inserted in the center thereof. And probe 34, spindle 3
5. The measuring pressure spring 36 and the like. Then, for example, the primary side of the differential transformer 30 is excited by an alternating current, and the secondary signal proportionally changed by the movement of the tracing stylus 34 directly connected to the core 33 is detected and output as a DC signal. The displacement is detected.

The fixed guide member 16 as an exterior member has a cylindrical measuring unit body 17 and sensor unit body 2.
4 is formed of a thin plate-shaped member 16 ′ that curves along the outer peripheral surface, and the plate-shaped member 16 ′ is engaged with the fixing pins 22 of the fixing rods 20 of the measuring unit 14 and the sensor unit 15. A hole 29 is provided, and each measuring pin 14 and the sensor unit 15 are fixed to the fixed guide member 16 by projecting each fixing pin 22 and locking the fixing pin 22 in each locking hole 29. In FIG. 2, reference numeral 40 denotes a support leg that is attached to the outer peripheral surfaces of the measuring unit 14 and the sensor unit 15. The support leg 40 connects the wall surface of the well 13 and the outer peripheral surface of the measuring unit 14 and the sensor unit 15. The space is maintained to protect the plate-shaped member 16 ', and the fixed guide member 16, that is, the plate-shaped member 16' is easily removed.

Further, as shown in FIG. 1, the fixed guide member 16 is provided with a wheel type centrizer 30 as a supporting carriage following the plate-shaped member 16 '. Some extend from the wheel type centralizer 30 to the front, and the wheel type centralizer 30 has an extension rod 31 that extends rearward to reach the hole opening.
Are connected. In addition, this wheel-type centrizer 30
Further, a borehole television 32 for viewing the wall surface of the well 13 is attached to the.

The LVDT displacement sensor 26 of the sensor unit 15 is connected to an amplifier, an AD converter, a CPU for measurement control and data / file management, a data recording memory, etc. of the LVDT displacement sensor 26 via various connection lines. is doing.

In order to measure the displacement of the crack surface 11 in the bedrock 12 using the discontinuous surface displacement gauge 10 having the above-mentioned structure, first, in the well 13 previously drilled, the crack is formed. The discontinuous surface displacement meter 10 is installed with the surface 11 interposed therebetween. That is, the discontinuous surface displacement meter 10 is inserted into the well 13 while being fixed integrally to the fixed guide member 16, and the extension rods 31 are successively added and pushed into the well 13 to slide and move the fixed guide member 16. Let At this time, since the fixed guide member 16 is provided with the wheel type centrizer 30, the fixed guide member 16 can be smoothly moved within the well 13, and the hole is provided via the borehole television 32 provided in the wheel type centralizer 30. The wall surface of the well 13 is visually inspected, and the exact position of the crack surface 11 can be confirmed.

The crack surface 11 by the borehole television 32.
When the position of is confirmed, the fixed guide member 16 is pulled back by a predetermined length, and the discontinuous surface displacement gauge 1
0, and the measuring unit 14 and the sensor unit 15 are each equipped with a well 1
Fix in 3. That is, for example, the pressure line 21
When the hydraulic pressure applied to the fixed rod 20 is reduced through the hydraulic cylinder, the hydraulic cylinder slides by the repulsive force of the spring, pulling in the fixing pin 22 and projecting the hole wall crimping portion 23 in the opposite direction. Therefore, the locking hole 2
The fixing state of the measuring unit 14 and the sensor unit 15 with the fixed guide member 16 is released by the engagement with the fixing member 9, and the hole wall crimping unit 23 presses the hole wall surface to move the measuring unit 14 and the sensor unit 15 to each other. Firmly fix each inside 13. The fixed guide member 16 in the fixed state is released from the extension rod 3
It is pulled out via 1 and collected and removed together with the borehole television 32. Here, the discontinuous surface displacement meter 10 is fixed to the fixed guide member 1 until the discontinuous surface displacement meter 10 is installed.
6 is fixed, the relative position between the measuring unit 14 and the sensor unit 15 is maintained constant, which causes the bias of the desired fixed position of the LVDT displacement sensor 26 when the displacement meter is installed. It is possible to eliminate a measurable range, a deviation, or a measurement error.

According to the discontinuous surface displacement meter 10 fixed at a predetermined position with the crack surface 11 sandwiched in this way, fluctuations of the specified crack surface 11 can be three-dimensionally and easily and highly accurately. It can be measured for a long time. That is, the displacement of three mutually orthogonal planes provided on one ground sandwiching the crack surface 11 is opposed to the three planes provided on the other ground.
By tracking with the VDT displacement sensor 26, the three-dimensional relative displacement of the ground sandwiching the crack surface 11 is observed with high accuracy, and the LVDT displacement sensor 26 of the sensor unit 15 is connected via various connection lines. Since it is connected to the amplifier of the LVDT displacement sensor 26, the AD converter, the CPU that performs measurement control and data / file management, the data recording memory, etc., the behavior of the crack surface 11 is automatically observed for a long time by these. be able to.

When the measurement is completed after a lapse of a predetermined period of time, the pressure on the hole wall surface by the hole wall pressure bonding portion 23 is released to recover the discontinuous surface displacement gauge 10. When a step is formed in 13, the measuring unit 14 and the sensor unit 15 are separated and only the sensor unit 15 is collected.

Further, in this embodiment, three orthogonal planes are adopted as at least three intersecting planes, but the present invention is not limited to this, and the displacement can be measured using three or more planes. it can.

[0023]

As described above in detail, according to the displacement measuring method for a discontinuous surface of the present invention, a measuring section having at least three surfaces intersecting each other is provided on one side of the discontinuous surface in the well. Along with the discontinuous surface, a sensor unit having a displacement sensor in at least three axial directions is installed on the other side, and displacement of the discontinuous surface is measured by measuring displacements of at least three surfaces intersecting with each other by respective displacement sensors. Since the three-dimensional measurement is performed, the three-dimensional behavior of the ground can be easily evaluated, and the deformation of the discontinuous surface, which controls most of the ground deformation, can be measured by the specific measurement. Highly accurate and effective evaluation can be easily performed.

When the measuring unit and the sensor unit are respectively installed, if the measuring unit and the sensor unit are previously integrally fixed to a detachable fixed guide member and moved in the borehole, the moving measuring unit can be moved. By maintaining the relative position between the sensor and the sensor unit constant, it is possible to easily eliminate a measurement range reduction, deviation, or measurement error due to the deviation of the intended fixed position of the LVDT displacement sensor 26 when the displacement meter is installed. be able to.

Further, according to the discontinuous surface displacement meter of the present invention, the above discontinuous surface displacement measuring method can be easily implemented.

If a borehole television is provided on the fixed guide member of the discontinuous surface displacement gauge of the present invention, the position of the discontinuous surface in the borehole can be easily specified.

If the fixed guide member is provided with a wheel type centrifuge, the movement in the borehole can be carried out smoothly.

Further, if the differential transformer displacement sensor is connected to the amplifier of this differential transformer displacement sensor, the AD converter, the CPU for measurement control and data file management, the data recording memory, etc. The displacement can be automatically observed over a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a situation in which the displacement of a crack in rock is measured by the continuous surface displacement measuring method of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a measurement unit and a sensor unit.

FIG. 3 is a sectional view showing an example of a differential transformer displacement sensor.

[Explanation of symbols]

 10 Discontinuous Surface Displacement Meter 11 Crack Surface (Discontinuous Surface) 12 Rock Bed 13 Powell 14 Measuring Section 15 Sensor Section 16 Fixed Guide Member 19 Three Sides 20 Fixed Rod (Fixing Means) 21 Pressure Line 26 Differential Transformer Displacement Sensor 29 Engagement Stop hole 30 Wheel type sensor riser 32 Borehole TV

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Tamai 2-3 Kandaji-cho, Chiyoda-ku, Tokyo Obayashi Corporation Tokyo Head Office

Claims (6)

[Claims] 1. A method for measuring the displacement of a discontinuous surface such as a crack surface in rock mass, which comprises drilling a borehole across the discontinuous surface, wherein the discontinuous surface is formed in the borehole. A measuring unit having at least three surfaces intersecting each other is installed on one side of the sandwiching unit, and a sensor unit having displacement sensors in at least three axial directions facing the at least three faces of the measuring unit on the other side of the discontinuous plane. And measuring the displacements of at least three surfaces intersecting each other by respective displacement sensors, thereby measuring the three-dimensional displacements of the discontinuous surface. 2. When the measurement unit and the sensor unit are installed with the discontinuous surface in the borehole interposed therebetween, the measurement unit and the sensor unit are previously integrally fixed to a detachable fixed guide member, and the fixed guide is provided. Insert the measuring unit and the sensor unit that are integrated by a member into the well and move to a measuring position that sandwiches the discontinuous surface, and fix the measuring unit and the sensor unit in the well, respectively, and then fix the fixed guide member. The displacement measuring method for a discontinuous surface according to claim 1, wherein the measuring unit and the sensor unit are installed in the borehole by removing the measuring unit and the sensor unit. 3. A discontinuous surface displacement gauge for measuring the displacement of a discontinuous surface such as a crack surface in rock mass, which is a first tubular member, and has at least three surfaces which intersect at one end with each other. And a measuring section having a fixing means that moves forward and backward in at least two directions outwardly in the radial direction of the tubular member by means of expansion and contraction means such as a hydraulic cylinder and a spring, and a second tube that is continuous with the measuring section. A member having a differential transformer displacement sensor in at least three axial directions, which is arranged to face each of the at least three surfaces, at an end portion of the measuring member facing the one end portion having at least three surfaces of the measuring portion, and a hydraulic pressure. A sensor portion having a fixing means capable of advancing and retreating in at least two directions outwardly in the radial direction of the tubular member by an expansion and contraction means such as a cylinder and a spring; The measuring part and the sensor part are integrated by having locking holes for locking the fixing parts of the sensor part and projecting and locking the fixing parts of the measuring part and the sensor part. A discontinuous surface displacement meter comprising a fixed guide member for fixing. 4. The discontinuous surface displacement meter according to claim 3, wherein the fixed guide member includes a borehole television for visually confirming the discontinuous surface. 5. The discontinuous surface displacement meter according to claim 3, wherein the fixed guide member includes a wheel type centrizer. 6. The discontinuous surface displacement gauge is connected to the differential transformer displacement sensor, an amplifier of the differential transformer displacement sensor, an AD converter, a CPU for measurement control and data file management, and a data recording. The discontinuous surface displacement meter according to claim 3, further comprising a memory.