JPH01101444A - Testing method for impulse response of ground or the like and suspension type layer inspector - Google Patents

Abstract

PURPOSE:To easily grasp the properties of a material by striking an impact hammer wherein an accelerometer is incorporated with a solenoid hammer and then striking an object material with the impact hammer and finding the current response waveform of the accelerometer. CONSTITUTION:The solenoid hammer 5 suspended by leaf springs 4 is put in operation by applying a high pulse voltage to a coil 7 to strike the impact hammer 3 suspended by leaf springs 2, thereby striking the object material 6 with the impact hammer 3. At this time, the output waveform of the acceleromter 1 incorporated in the impact hammer 3 is found. The amplitude Pmax and pulse width W in the section of the impact behavior between the impact hammer 3 and object body 6 vary according to the properties of the object material 6, so the relation between the ratio of those values and property values of various materials is found previously and the properties of the material 6 are estimated from the measured ratio.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to various materials such as rubber, concrete, and rock.
This article concerns the impact response test method for determining the physical properties of the ground, etc., and the application of this method to the field of well logging (suspended well logging equipment used).

<Conventional technology> In the Shore hardness tester, which is well known as a device for measuring hardness information, a hammer with a nearly spherical diamond at the tip is dropped onto the sample, and the height of the bounce is measured visually or with a dial gauge. It is being measured. In addition, the Schmidt Rock Hammer (trade name), which is used to estimate the strength of concrete materials and rocks or the deformation coefficient and elastic modulus of bedrock, as well as to quantitatively classify rock masses, is also used to estimate the impact of the impact caused by a hammer. The degree of repulsion R during action is automatically recorded. In addition, Echo Chip (trade name)
A portable universal hardness tester called ``Difficulty Tester'' uses a magnet built into the hammer and a coil placed around it to measure the striking speed V when the surface of the specimen is struck with the hammer. The hardness value "'L" (value of V/vo) is obtained from The hardness value "L 11" becomes larger if the hardness of the specimen is harder because the repulsion velocity V increases, and if the hardness is the same, a specimen with a smaller elastic modulus will have a larger value. Become.

On the other hand, in in-situ tests conducted to understand the physical properties of rock, etc., a speed logging sonde is suspended inside a polled well and a movable body installed inside the sonde is moved. A so-called suspended well logger is known that measures the propagation velocity of elastic waves in the stratum by applying a source force to the borehole wall surface through the borehole water in contact with the borehole wall surface.

This type of sonde uses an inflatable filter tube between the source and the geophone to ensure that the waves being detected are not blocked or masked by waves traveling through the borehole water column.

<Problem to be solved by the invention> The degree of repulsion R by the above-mentioned Schmidt rock hammer,
Based on past measurement examples, it can be said that the impact response value such as the hardness value it L re measured by the echo chip is an effective index for identifying and evaluating the physical properties of the target material. but,
From the point of view of wanting to more easily understand the physical properties of a wider range of target materials, this may not be fully satisfactory, so in the present invention, the repulsion degree R and the hardness value are different from the The object of this invention is to provide a impact response test method that can easily obtain new and more effective index values.

In addition, in order to make this test method applicable to the above-mentioned velocity logging, especially in a well where there is water in the borehole, it is necessary to seal the water with a flexible seam 1 to prevent water from entering through the gap around the striking hammer. In this case, water pressure equivalent to the water head is applied to the outside of the flexible sheet, but no pressure is applied to the inside, so the actual impact force from the impact hammer resists the water pressure. This creates an inconvenience in that the number of hits is forced to decrease as the number of hits is increased. The second aspect of the present invention, a suspended type well logger, is intended to eliminate such inconveniences.

Means for Solving the Problems> The method for testing the impact response of ground, etc. according to the present invention uses a percussion hammer that has an accelerometer incorporated inside and is suspended by a leaf spring.
Similarly, a solenoid hammer suspended by a leaf spring was used to directly impact the target material, and the impact response waveform measured by the accelerometer at that time was a waveform whose amplitude and pulse width could be easily measured. The value of the amplitude/pulse width ratio is used as an index value for the target material.

Further, the suspended type well logging device according to the present invention necessarily includes a fixed part that presses the inner wall surface of the well borehole when the well logging tool is suspended inside the wellbore.
It has a striking part that directly strikes the inner wall surface of the borehole, and a vibration receiving part that detects the elastic waves generated by the direct striking of the inner wall surface of the borehole. Similarly, a solenoid hammer suspended by a leaf spring and its driving coil are arranged facing each other, and the entry and exit points of the striking hammer are sealed with a flexible sheet, and water head pressure is applied to the outside of the flexible sheet. When the
A flexible air bag capable of receiving a water head pressure approximately equal to the water head pressure is attached in communication with the inside of the striking part.

<Effects of the Invention> According to the method of the present invention, the solenoid hammer and the impact hammer are each held by leaf springs, and the movement of the solenoid hammer is transmitted to the impact hammer, so that it is possible to obtain the impact response value of the target material. The impact force is kept constant each time, and the acceleration waveform is made so that the amplitude/pulse width ratio can be easily determined due to the action of the leaf spring. By using this ratio as an index value, it is possible to easily understand the physical properties of a wide range of materials. In addition to the impact response value described above, the elastic wave propagation velocity of the material near the impact point can be measured regardless of the presence or absence of water in the hole.

Furthermore, the suspended type well logger of the present invention is suitable for use in a borehole with limited space, especially for continuous use when there is water in the borehole during worship, and the impact force is reduced by the water head pressure. It is excellent in that it does not become weak.

<Example> First, an example of the impact response test method according to the present invention will be described. In the explanatory diagram of FIG. 1, a high-voltage pulse voltage is applied to the coil 7 to activate the solenoid hammer 5 suspended by the leaf spring 4, and by hitting the striking hammer 3 suspended by the leaf spring 2, the target is When the material 6 is hit 1 with the impact hammer 3, the output waveform of the accelerometer 1 installed in the impact hammer 3, in other words, the impact response waveform, is determined as follows.
As shown in Figure 2. Figure 2 - In the middle, point ■ is the collision point between solenoid hammer 5 and impact hammer 3, from point ■ to point ■
The section is a collision behavior section of both hammers 5 and 3 in which the impact hammer 3 receives and receives energy from the solenoid hammer 5,
The section from point ■ to point ■ is the section where the impact hammer 3 is moving toward the target material 6 due to the given energy,
Point ■ is the point where the impact hammer 3 and the target material 6 begin to collide, and in the area from point ■ to point ■, the target material 6 is the impact hammer 3
This is the collision behavior section in which energy is received from the vehicle. The waveform between points ■ and ■, that is, the amplitude p max and the pulse width W, change depending on the physical properties of the target material 6, and the action of the leaf spring 2 creates a waveform that is easy to measure as shown in the figure. It is easy to find the ratio Pmax/W. Third
Figures -A to 3-D show the relationships between pmax/W, unconfined compressive strength, dynamic elastic modulus, density, and P-wave velocity of various materials. From the same figure, it is clear that l) max/W is 1q, which is an index value of various material properties. Therefore, by understanding and accumulating many such relationships in advance, the obtained Pm
From the value of aX/W, it is possible to estimate the desired physical properties of the material.

Next, an embodiment of a suspended well logging device suitable for applying the method of the present invention to well logging in a borehole will be described. First, to outline the entire apparatus according to FIG. 4, a sonde Z suspended by a control cable 21 is inserted into a borehole 20 having water in the borehole. Although not shown in the drawings, there may be no water in the borehole 20 at all, or there may be water in the borehole from the middle of the prayer 20. The control cable 21 can be wound up and down by a winch 24 via a pulley 23 of a three-pronged turret 22, so that the sonde Z can be raised and lowered to an appropriate height. The control cable 21 is used to send electrical signals from the sonde Z inside the outside hole 20 to the measurement and recording device 25 on the ground, and to send the driving current and driving pressure required by the sonde Z inside the outside hole 20 from various equipment on the ground. It is carried out by

Figure 5 shows details of Sonde Z. This sonde Z has a pressure balance part A, a hammer part B, and a charge amplifier part C1.
First fixed part D, first vibration receiving part E and second fixed part [) /
, the second vibration receiving section E' are connected in series. Part B of the impact hammer is shown enlarged in FIG. 6, but its basic configuration is as explained in FIG. A percussion hammer 3 suspended by a spring 2 is disposed facing the percussion hammer 3, and an accelerometer 1 is mounted inside the percussion hammer 3. The striking hammer 3 directly strikes the inner wall surface of the prayer 20, and the striking force can be adjusted by controlling the current flowing through the coil 7 based on time, that is, by adjusting the pulse width. The structure not shown in Fig. 1 is that the gap around the striking hammer 3 is sealed with a flexible sheet 8 to prevent water from entering the hole even if there is water in the hole, and that the striking part B is closed. The interior thereof is in communication with the interior of the flexible air bag 9 provided in the pressure balance section A. The volume of the air bag 9 is set to be sufficiently large compared to the volume of the striking part B, and an opening 10 is bored in the housing of the pressure balance part A so that the air bag 9 can be opened when used underwater in the hole. Water pressure equivalent to the water head is applied to the outside.

By doing this, the pressure inside the air bag 9, which would be atmospheric pressure when there was no water in the hole, is compressed and increased to the point where it reaches equilibrium upon receiving the water pressure equivalent to the water head. The internal and external pressures are balanced, so that the striking force generated in the striking part B is not wasted due to the pressure difference.

Next, the charge amplifier section C has a battery 11 and a charge amplifier 12 installed inside its housing, and faithfully sends the signal from the accelerometer 1 incorporated in the striking hammer 3 to the ground measurement section, and also matches the two. Take. The first fixing portion serves to securely fix the sonde Z within the worship 20. In the illustrated example, the rubber film 13 swells due to the action of gas pressure, and the piston part 1 provided with the roller 14
5 moves toward the hole wall, and the roller 14 pushes the hole wall surface. Of course, there are other methods, such as inflating the air bag with pressurized air or extending the jacket with hydraulic pressure.
Appropriate means such as actuating the suppressing member with spring force can be adopted. The first vibration receiving section E is provided with a vibration receiving sensor in order to examine the propagation speed and frequency characteristics of the elastic waves generated by the impact.

FIG. 7 shows an example of the actual test results when the above-described suspended type logger was suspended in the church 20 as shown in FIG. 4 and the inner wall surface of the hammer 20 was directly struck. The impact response waveform in the impact portion B is shown in the first channel, and the received waveforms in the first vibration receiving portion E and the second vibration receiving portion E' are shown in the second channel and the third channel. From this impact response waveform, the pulse width/pulse width ratio described in Fig. 2 can be determined, and the physical properties can be determined from this.Furthermore, the frequency can be determined by paying attention to the initial motion of the waveform in the first vibration receiver E. be able to. Further, the propagation speed of the elastic wave can be determined from the propagation distance and propagation time between the first vibration receiving part E and the second vibration receiving part E'.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram to facilitate understanding of the method of the present invention, Fig. 2 is a diagram showing the impact response waveform, and Figs. 3-A to 3-0 show the imaging width and width of various materials. A diagram showing the relationship between pulse width ratio, uniaxial compressive strength, dynamic elastic modulus, density, and P-wave velocity. Figure 4 is an explanatory diagram of the entire suspended logging device. Figure 5 shows the sonde divided into three parts. FIG. 6 is an enlarged view of the striking part, and FIG. 7 is a diagram showing an actual striking response waveform. 1... Accelerometer, 2... Leaf spring, 3... Impact hammer, 4... Leaf spring, 5... Solenoid hammer,
7... Coil, 8... Flexible sheet, 9... Flexible air bag. @3-A drawing machine width: 1 inch x, 9 (V/m5) IE3-8 drawing width: width (V/ms) - D figure vein width / l axis width (V/m5) s4 figure f47 figure clear interval (ms)

Claims (1)

[Claims] 1. A striking hammer in which an accelerometer is incorporated and suspended by a leaf spring is struck by a solenoid hammer also suspended by a leaf spring, and the striking hammer directly hits the target material, and the above-mentioned at that time. A method for testing the impact response of the ground, etc., characterized in that the impact response waveform measured by an accelerometer is made into a waveform whose amplitude and pulse width can be easily measured, and the obtained value of the amplitude/pulse width ratio is used as an index value for the target material. . 2. A logging tool suspended in a wellbore, which includes a fixed part (D, D') that presses the inner wall of the wellbore, a striking part (B) that directly hits the inner wall of the wellbore, and a logging tool that directly hits the inner wall of the wellbore. It has a vibration receiving part (E, E') that detects the elastic waves generated by a strike, and the striking part (B) is a striking hammer in which an accelerometer (1) is incorporated and is suspended by a leaf spring (2). (3), a solenoid hammer (5) similarly suspended by a leaf spring (4), and its driving coil (7) are arranged facing each other, and the entry and exit points of the impact hammer (3) are made flexible. A flexible air bag (9) that can be sealed with a sheet (8) and can receive a head pressure approximately equal to the head pressure when a head pressure is applied to the outside of the flexible sheet (8) is attached to the striking part. (B) A suspended well logging device characterized by being installed in communication with the inside.