JP4340738B2 - Apparatus and method for measuring pore diameter change - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hole diameter change measuring device and a hole diameter change measuring method for measuring an initial stress by measuring a hole diameter change of a borehole drilled in a rock before and after coring.
[0002]
[Prior art]
Japanese Patent Application No. 9-279140 describes a rock mass fluctuation measuring device that measures the initial stress acting on the rock mass.
[0003]
The rock mass fluctuation measuring device described in Japanese Patent Application No. 9-279140 measures the displacement of the rock mass in an arbitrary direction by arranging displacement sensors in an arbitrary direction, and measures the pressure component in an arbitrary direction with one device. It is configured to be possible.
[0004]
[Problems to be solved by the invention]
However, according to the rock mass fluctuation measuring device described above, the measuring device must be buried in the boring hole with cement milk. In other words, a large amount of cement milk is poured into the borehole so that the measuring device is covered with cement milk, the measuring device is inserted into the cement milk before the cement milk is solidified, and then the extra coring operation is hindered. Remove the cement milk and wait for the cement to solidify.
[0005]
In order to embed the above-mentioned rock mass fluctuation measuring device, it is necessary to perform the above-mentioned work in a limited time until the cement milk solidifies, and the device cannot be buried at a deep point. Therefore, it is difficult to measure the initial stress at deep points. Furthermore, until the cement milk is solidified, the coring work cannot be performed, which requires a considerable number of days and requires a lot of expenses. The initial stress can be measured only at the bottom of the borehole where cement milk can be poured.
[0006]
The present invention has been considered in view of the above problems, and the object of the present invention is to install a measuring device on the hole wall of the borehole without using cement milk, perform coring, inject cement milk, Providing a hole diameter change measuring device that eliminates the work of removing excess cement milk, eliminates the need to wait for the cement milk to solidify, requires fewer work days, and can measure the hole diameter change of boreholes even at deep locations, and changes in hole diameter It is to provide a measurement method.
[0007]
[Means for Solving the Problems]
As described in claim 1, the pore diameter change measuring device according to the present invention comprises:
A bore diameter change measuring device that is installed on the bore wall of a borehole drilled in the rock mass and detects the initial stress acting on the rock mass by detecting the bore diameter change before and after coring,
Means for converting a change in pore diameter into an electrical signal, means for converting the electrical signal into digital data, a memory for storing the converted digital data, and causing the external device to read data on the pore diameter change stored in the memory Data transmission means and a power supply battery are integrated into one unit.
[0008]
As described in claim 2, the pore diameter change measuring device of the present invention includes:
An azimuth measuring means is integrated, and the azimuth measuring means measures the azimuth of the installed hole diameter change measuring device, and the azimuth data is stored in the memory together with the hole diameter change data.
[0009]
As described in claim 3, the pore diameter change measuring device according to the present invention comprises:
A temperature measuring means is integrated, and the temperature measuring means measures the temperature of the inside and the side of the hole diameter change measuring device, and the temperature data together with the hole diameter change data is stored in the memory.
[0010]
As described in claim 4, the pore diameter change measuring device of the present invention includes:
Pressure measuring means is incorporated integrally, and the pressure measuring means measures the pressure inside and side surfaces of the hole diameter change measuring device, and the pressure data together with the hole diameter change data is stored in the memory.
[0011]
As described in claim 5, the pore diameter change measuring device according to the present invention includes:
A scheduler is integrated, and the scheduler has a schedule for storing pore diameter change data, orientation data of the pore diameter change measuring device, temperature data inside and outside the device, and pressure data inside and outside the device in the memory. It is set in advance.
[0012]
As described in claim 6, the pore diameter change measuring device according to the present invention includes:
A microprocessor is incorporated integrally, and the operation content of each means constituting the hole diameter change measuring device is controlled by a control signal of the microprocessor.
[0013]
The pore diameter change measuring method of the present invention is as described in claim 7,
The pore diameter change measuring device according to any one of claims 1, 2, 3, 4, 5, or 6,
A process of installing on the hole wall of the borehole;
Before and after coring,
Measuring the change in the hole diameter, the orientation of the measuring device, the temperature inside or outside the measuring device, the pressure inside or outside the measuring device,
Storing the measured data in the memory;
After coring,
Removing the hole diameter change measuring device from the borehole while standing still at a position where the water depth is known;
Reading the digital data stored in the memory into an external device, estimating the initial stress acting on the rock mass based on the data read into the external device by inverse analysis,
From the above, a series of processes is constructed.
[0014]
[Effects of the invention]
The hole diameter change measuring device of the present invention according to claim 1 comprises a means for converting a change in hole diameter into an electric signal, a means for converting the electric signal into digital data, a memory for storing the converted digital data, Data transmission means for reading data on hole diameter changes stored in the memory into an external device and a battery for power supply are integrated and installed on the hole wall of the hole, and the hole diameter changes before and after coring. It is configured to measure the initial stress acting on the rock mass by performing the inverse analysis (inversion).
[0015]
For this reason, sensors can be arranged in any direction as in the rock mass fluctuation measuring device described in Japanese Patent Application No. 9-279140, and the change in the hole diameter in any direction can be measured before and after coring. Similarly to the rock mass fluctuation measuring device described above, the change in the direction can be understood by measuring the change in the hole wall in the direction parallel to or oblique to the borehole. Moreover, the hole diameter change measuring device has a built-in battery for power supply, and no power supply or signal cable is connected to external equipment. For this reason, coring can be easily performed even at deep points. In addition, since no connection cable is required, coring in a direction oblique to the borehole can be easily performed near the instrument. In particular, the embedding with cement milk, which was necessary for the above-mentioned rock mass fluctuation measuring device, is unnecessary, coring can be performed immediately after the hole diameter changing measuring device is installed on the hole wall, the number of working days can be reduced, and the borehole A hole diameter change measuring device can be installed at any depth, and the change in hole diameter can be measured at any depth.
[0016]
In order to obtain the initial stress direction by inverse analysis, it is necessary to know which direction the hole diameter change was measured, and the installation direction of the hole diameter change measuring device must be obtained. However, if the hole diameter change measuring device incorporates an azimuth measuring means, the installation direction of the device can be known and the work of measuring the azimuth of the device need not be performed.
[0017]
With a hole diameter change measuring device incorporating a temperature measuring means, the temperature inside and outside the measuring device before and after coring can be known, and fluctuations in the output of the electronic circuit inside the measuring device due to temperature and deformation of the device due to temperature. The influence can be corrected, the error of the hole diameter change data before and after coring is reduced, and the accuracy of the inverse analysis can be improved. In particular, during coring, high-pressure cooling water must be supplied, and the temperature inside and outside the measuring device must be measured to compensate for the temperature-independent effects of sending cooling water. There is.
[0018]
With a hole diameter change measuring device that incorporates pressure measuring means, the pressure inside and outside the measuring device before and after coring can be determined, and the effects of deformation of the device due to pressure changes can be corrected. The error of the data becomes smaller and the accuracy of the inverse analysis can be improved. In particular, during coring, high-pressure cooling water must be supplied, and pressure inside and outside the measuring device is measured to compensate for the effects of pressure changes that do not depend on the true stress caused by sending cooling water. There is a need.
[0019]
Then, a scheduler is incorporated in the device, and by using this scheduler, for example, a power supply battery is scheduled to be supplied to each device only before and after coring in the vicinity of the device, thereby suppressing the consumption of the power supply battery. be able to.
[0020]
In addition, if a microprocessor is incorporated in the device and the operation of each device is controlled by the microprocessor, the sensitivity for measuring changes in pore diameter before and after coring can be changed and the sampling interval can be shortened. By performing this control, the quality of the hole diameter change data before and after coring is improved, and the accuracy of the inverse analysis can be improved.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the embodiment of the present invention will be described with reference to the drawings.
[0022]
Fig. 1 shows the specifications of the hole diameter change measuring device according to one embodiment, Fig. 2 shows other specifications of the device, and Fig. 3 shows the configuration of the device.
[0023]
As shown in FIG. 3, the hole diameter change measuring apparatus 1 of the present embodiment includes means 110 for converting changes in hole diameter in one or a plurality of directions into electrical signals, means 120 for converting the signals into digital data, and a memory. 130, digital data transmission means 140, and a battery 150 for power supply, and these devices 110, 120, 130, 140, 150 are integrally incorporated.
[0024]
The means 110 for converting the change in the hole diameter into an electric signal is a means for detecting the change in the hole diameter during coring (including the rock inclination), for example, on the same plane as shown in FIG. Displacement sensors are arranged at 120 ° intervals to measure the displacement of the hole wall in three directions, an inclinometer is used to measure the inclination in any direction, and strain gauges are arranged in three directions to arrange the hole wall. Measure displacement by converting it to strain. Also, ultrasonic waves and light are emitted from the center of the borehole to the hole wall, and the time difference until the ultrasonic wave is reflected from the hole wall is measured, and the phase difference of the light reflected from the hole wall is measured. Then, the displacement of the hole wall is obtained. On the other hand, by arranging metal on the hole wall, the change in hole diameter in any direction can be converted into an electric signal by using electromagnetic induction or by changing the capacitance.
[0025]
The means 120 for converting the electrical signal into digital data is, for example, an analog / digital converter that converts an analog signal, a counter that converts a frequency, a reference oscillation frequency by using a time difference as a gate time, and a change in pore diameter. Converts to a digital value.
[0026]
The memory 130 is, for example, an SRAM or a flash memory, and is connected to the means 120 for converting to digital data, and stores data on the hole diameter change by the means 120 for converting to digital data.
[0027]
The data transmission means 140 is connected to the memory 130 and causes the data on the hole diameter change stored in the memory 130 to be read by an external device (not shown) installed on the ground surface, and collected on the ground after coring. At the time, the cable is connected and the hole diameter change data in the memory 130 is sent to the external device via the cable, or the hole diameter change is made by non-contact means using electromagnetic waves, ultrasonic waves, infrared rays, visible light, etc. as a medium. It consists of electronic circuits that send data to external devices. Here, the external device obtains the initial stress acting on the rock based on the pore diameter change data read via the data transmission means 140.
[0028]
The power source battery 150 serves as a power source for the means 110 for converting the hole diameter change into an electric signal, the means 120 for converting the electric signal into digital data, the memory 130 and the data transmission means 140.
[0029]
Next, a method for measuring the initial stress acting on the rock using the hole diameter change measuring apparatus 1 configured as described above will be described with reference to FIGS. In the normal case, the boring hole is excavated with a small-diameter boring hole 3 and then expanded to a large-diameter boring hole 4 to obtain the desired large-bore boring hole 4. The method for measuring the initial stress described below is performed after the drilling hole 3 having the small diameter is excavated.
[0030]
First, as shown in FIG. 5, the upper portion of the hole diameter change measuring device 1 is divided into two metal portions 10, and the two metal portions 10 are connected by a spring 20, so that the outer diameter of the hole diameter change measuring device 1 is free. The configuration can be changed to. Then, the two metal portions 10 are formed so as to protrude in the outer diameter direction, and protrusions 30 are provided on the upper portions of the left and right metal portions 10. On the other hand, a hole 60 is made on the left and right sides of the metal plate 50 attached to the tip of the boring rod 40, and the protrusion 30 is fitted into the hole 60, and the rod is measured with the outer diameter of the upper portion of the hole diameter change measuring device 1 being reduced. Attach to 40 tips. When the device 1 thus attached to the rod 40 is lowered into the boring hole 4 having a large hole diameter, the portion protruding in the outer diameter direction of the metal portion 10 hits the bottom 70 of the boring hole 4 having a large diameter, The protrusion 30 in a state of being fitted in the hole 60 of the plate 50 is detached, and the outer diameter of the device 1 is expanded by the action of the spring 20 so that the device 1 is in close contact with the hole wall so that the change in the hole diameter can be measured. Become.
[0031]
Although not shown here, the method of connecting the hole diameter change measuring device 1 to the rod 40 is changed, and when the water pressure is applied to the rod, the device 1 is detached from the rod and can be installed on the hole wall of the small-diameter boring hole 3 This makes the installation of the device 1 easier. Further, even if a plate spring is attached to the side surface of the hole diameter change measuring device 1 and the device 1 is brought into close contact with the hole wall of the small-diameter boring hole 3 by the action of the plate spring, the device 1 can be installed easily. On the other hand, even if a small motor is incorporated in the hole diameter change measuring device 1 and the side surface of the device 1 is expanded by the action of the motor and is closely attached to the hole wall, the device 1 can be installed easily.
[0032]
As shown in FIG. 1, large-diameter coring is performed up to the depth where the hole diameter change measuring device 1 is installed, or as shown in FIG. Coring is performed to release the initial stress acting on the rock mass 2 (strictly, the core 5). In addition, the code | symbol 6 shown in FIG. 1 exists in the circumference | surroundings of the core 5, and the cylindrical rock mass part removed by coring, and the code | symbol 7 shown in FIG. 2 also represents the rock mass part removed by coring. . The initial stress is released by coring, and before and after the coring, the electric signal by the means 110 for converting the hole diameter change into an electric signal is input to the means 120 for converting to digital data, and the hole diameter is sampled at a predetermined sampling period. The change data is stored in the memory 130.
[0033]
Then, after coring, the core 5 including the hole diameter change measuring device 1 is taken out from the bore hole 3, and when the data transmission means 140 is a connector, a cable is connected to the connector and the hole diameter change data in the memory 130 is externally transmitted. Load the device (not shown). If the data transmission means consists of an electronic circuit that is a non-contact means using electromagnetic waves, ultrasonic waves, infrared rays, visible light, etc. as a medium, the data on the hole diameter change is read directly by an external device. In the external equipment, the initial stress acting on the rock mass 2 (strictly, the core 5) is obtained by inverse analysis (inversion) based on the read hole diameter change data.
[0034]
When the core 5 is taken out from the boring hole 3, the water pressure applied to the core 5 changes according to the water depth. Therefore, if the core 5 is stopped at a position where the water depth is known, the core 5 is pressurized, and the relationship between the displacement of the hole diameter of the cut rock (core 5) constituting the rock and the applied pressure can be understood. . If the depth of water is changed intentionally, pressure is applied to the water in the borehole, the detailed relationship between the water pressure applied to the core 5 and the change in hole diameter is obtained, and if the data is read with an external device, the elastic constant of the rock mass can be found, The accuracy of the analysis can be improved.
[0035]
Further, if the core 5 taken out from the borehole 3 is stored in a place where the temperature change is small, such as an underground tunnel, with the hole diameter change measuring device being operated, it is not affected by the temperature change. The change in the hole diameter of the core 5 after the initial stress release can be measured. And the elastic constant of the rock mass can be determined based on the data at that time, and the accuracy of the inverse analysis is improved. Further, after the hole diameter change measuring device 1 is installed, the measurement of the hole diameter change is continued for a certain period in the boring hole in a state where the coring is performed, and then the core 5 is taken out and the data is read by an external device. Has the effect of
[0036]
As described above, the hole diameter change measuring apparatus 1 according to the present embodiment includes the means 110 for converting the hole diameter change into an electrical signal, the means 120 for converting the signal into digital data, the memory 130, and the data of the digital data. The transmission means 140 and the power source battery 150 are integrated into one body and installed in the small-diameter boring hole 3 excavated in the rock mass 2 to act on the rock mass 2 (strictly, the core 5) during coring. It is configured to measure the initial stress. For this reason, the displacement of the rock in any direction can be measured by measuring the change of the hole diameter by arranging the sensor in the arbitrary direction and measuring the change of the hole wall. In addition, since the hole diameter change measuring device 1 is not connected with a cable for connection with an external device, coring can be easily performed. In particular, unlike the rock mass fluctuation measuring apparatus described in Japanese Patent Application No. 9-279140, it is not necessary to embed it with cement milk, so that the apparatus 1 can be easily installed, and a small-bore borehole 3 is expanded. There is an advantage that the initial stress can be measured at an arbitrary depth during the work to make the bore hole 4 with a large diameter.
[0037]
FIG. 6 shows the configuration of a hole diameter change measuring apparatus according to another embodiment. The pore diameter change measuring apparatus 1 further includes a scheduler 160, and the scheduler 160 has a configuration in which a schedule for storing pore diameter change data in the memory 130 is set in advance. According to the hole diameter change measuring apparatus 1, the scheduler 160 schedules the power supply from the power supply battery 150 to the devices 110, 120, 130, and 140 constituting the apparatus only before and after coring in the vicinity of the apparatus. In addition, the consumption of the power battery 150 can be suppressed.
[0038]
FIG. 7 shows the configuration of a hole diameter change measuring apparatus according to still another embodiment. The hole diameter change measuring apparatus 1 has a configuration in which a microprocessor 170 is incorporated in the apparatus shown in FIG. 6 and the operation content of each device 120, 130, 140, 150, 160 is controlled by a control signal of the microprocessor 170. Take. According to this hole diameter change measuring apparatus 1, the core near the apparatus 1 which is important for the measurement of the initial stress is controlled by the microprocessor 170, for example, by controlling the sampling number for creating the hole diameter change data, the amplification factor, and the like. The data quality of the hole diameter change during ring can be improved.
[0039]
FIG. 8 shows the configuration of a hole diameter change measuring apparatus according to still another embodiment. This hole diameter change measuring apparatus 1 is integrated with the direction measuring means 180 such as a gyrocompass in the apparatus shown in FIG. 7, and the direction data measured by this direction measuring means 180 is also stored in the memory 130 to change the hole diameter. Together with the data, the data transmission means 140 is configured to be read into an external device. According to this hole diameter change measuring device 1, it can be understood which direction of hole diameter change data was obtained regardless of the installation state of the device 1.
[0040]
FIG. 9 shows the configuration of a hole diameter change measuring apparatus 1 according to still another embodiment. The hole diameter change measuring device 1 includes temperature measuring means 190 such as a quartz thermometer integrally incorporated in the apparatus shown in FIG. 8, and temperature data measured by the temperature measuring means 190 inside and outside the apparatus. The data is stored in the memory 130 and is read into the external device by the data transmission means 140 together with the hole diameter change data. According to this hole diameter change measuring device 1, it is possible to know the temperature change inside and outside the device regardless of the installation state of the device, and to correct the influence of temperature on the hole diameter change data.
[0041]
FIG. 10 shows the configuration of a hole diameter change measuring apparatus 1 according to still another embodiment. This hole diameter change measuring device 1 is constructed by integrating a pressure measuring means 200 such as a bellows type pressure gauge into the device shown in FIG. 9 and measuring pressure data inside and outside the device measured by the pressure measuring means 190. Is also stored in the memory 130 and is read into the external device by the data transmission means 140 together with the data of the hole diameter change. According to this hole diameter change measuring device 1, it is possible to know changes in pressure inside and outside the device regardless of the installation state of the device, and to correct the influence of pressure on the hole diameter change data.
[0042]
In Fig. 1 and Fig. 2, the method of measuring the hole diameter change before and after coring at an arbitrary position of the boring hole when the hole diameter of the small boring hole 3 is increased is described. The same thing can be done at the bottom of the small bore boring hole 3. In addition, the bore diameter change can be measured in the same way as described above for boreholes excavated horizontally or obliquely.
[0043]
If a rechargeable battery 150 is used as the power supply battery 150, charging by a connector or electromagnetic induction can be performed, and the labor and frequency of battery replacement can be reduced.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing the specifications of a hole diameter change measuring apparatus according to an embodiment, in which (A) is a sectional view and (B) is a perspective view.
FIGS. 2A and 2B are diagrams showing other specifications of the measuring apparatus, in which FIG. 2A is a cross-sectional view and FIG.
FIG. 3 is a block diagram of the apparatus.
FIG. 4 is a diagram showing an arrangement example of means for converting the hole diameter change of the device into an electric signal.
FIGS. 5A and 5B are a view showing a specification in which a hole diameter change measuring device according to one embodiment is attached to the tip of a rod and installed in a borehole, where FIG. 5A is a cross-sectional view and FIG.
FIG. 6 is a configuration diagram of a hole diameter change measuring apparatus according to another embodiment.
FIG. 7 is a configuration diagram of a hole diameter change measuring apparatus according to still another embodiment.
FIG. 8 is a configuration diagram of a hole diameter change measuring apparatus according to still another embodiment.
FIG. 9 is a block diagram of a hole diameter change measuring apparatus according to still another embodiment.
FIG. 10 is a configuration diagram of a hole diameter change measuring apparatus according to still another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hole diameter change measuring apparatus 2 Rock bed 3 Small bore boring hole 4 Large bore boring hole 5 Core 6 Rock bed 7 Rock bed 10 Metal part 20 Spring 30 Protrusion 40 Rod 50 Metal plate 60 Hole 70 Bottom 110 of large bore boring hole Change in bore diameter 120 means for converting electric signal into electric signal 130 means for converting electric signal into digital data 130 memory 140 data transmission means 150 battery for power supply 160 scheduler 170 microprocessor 180 orientation measuring means 190 temperature measuring means 200 pressure measuring means

Claims (7)

A hole diameter change measuring device that is installed in the hole wall of a borehole drilled in the rock mass without using cement milk and detects the initial stress acting on the rock mass by detecting the change in the borehole diameter before and after the coring. A means for converting a change in pore diameter into an electrical signal; a means for converting the electrical signal into digital data; a memory for storing the converted digital data; and a memory for storing the converted digital data on the ground after coring. A hole diameter change measuring device characterized in that a data transmission means for causing an external device to read stored hole diameter change data and a power source battery are integrally incorporated. The azimuth measuring means is integrally incorporated, and the azimuth measuring means measures the azimuth of the installed hole diameter change measuring device, and the azimuth data is stored in the memory together with the hole diameter change data. The pore diameter change measuring device as described. A temperature measuring means is integrally incorporated, and the temperature of the inside and the side of the hole diameter change measuring device is measured by the temperature measuring means, and the temperature data is stored in the memory together with the hole diameter change data. The pore diameter change measuring device according to claim 1 or 2. A pressure measuring means is integrated, and the pressure measuring means measures the pressure inside and on the side of the hole diameter change measuring device, and the pressure data together with the hole diameter change data is stored in the memory. The pore diameter change measuring device according to claim 1, claim 2 or claim 3. A scheduler is integrated into the memory, and the hole diameter change data, the hole diameter change measuring device orientation data, the temperature data inside and outside the device, and the pressure data inside and outside the device are stored in the memory. The pore diameter change measuring device according to claim 1, wherein a schedule is set in advance. A microprocessor is integrally incorporated, and the operation contents of each means constituting the hole diameter change measuring device are controlled by a control signal of the microprocessor. 6. A pore diameter change measuring device according to claim 4 or claim 5. The pore diameter change measuring device according to any one of claims 1, 2, 3, 4, 5, or 6,
A process of installing on the hole wall of the borehole;
A step of storing the measured digital data in the memory before and after coring, and a step of taking out the hole diameter change measuring device from the borehole while standing still at a position where the water depth is known after coring,
A series of steps consists of a step of reading the digital data stored in the memory into an external device and a step of estimating the initial stress acting on the rock mass by back analysis based on the data read into the external device. A pore diameter change measuring method characterized by comprising.

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