CN110333295B - Rock-soil core sample wave speed testing system and method - Google Patents
Rock-soil core sample wave speed testing system and method Download PDFInfo
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- CN110333295B CN110333295B CN201910717014.8A CN201910717014A CN110333295B CN 110333295 B CN110333295 B CN 110333295B CN 201910717014 A CN201910717014 A CN 201910717014A CN 110333295 B CN110333295 B CN 110333295B
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- 238000012360 testing method Methods 0.000 title claims abstract description 59
- 239000002689 soil Substances 0.000 title claims abstract description 57
- 238000000034 method Methods 0.000 title claims description 29
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 claims abstract description 9
- 238000010998 test method Methods 0.000 claims abstract 6
- 239000011435 rock Substances 0.000 claims description 39
- 230000005284 excitation Effects 0.000 claims description 16
- 230000035945 sensitivity Effects 0.000 claims description 11
- 230000000737 periodic effect Effects 0.000 claims description 9
- 238000010219 correlation analysis Methods 0.000 claims description 4
- 238000004364 calculation method Methods 0.000 claims description 3
- 230000006835 compression Effects 0.000 description 15
- 238000007906 compression Methods 0.000 description 15
- 230000000694 effects Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
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- 238000005259 measurement Methods 0.000 description 3
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- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/043—Analysing solids in the interior, e.g. by shear waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/045—Analysing solids by imparting shocks to the workpiece and detecting the vibrations or the acoustic waves caused by the shocks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
Abstract
The invention is applicable to the technical field of engineering test, and provides a rock-soil core sample wave velocity test system and a rock-soil core sample wave velocity test method, wherein the system comprises the following components: the device comprises a signal generation module, a steady-state vibration exciter, a connecting rod, a connector, a first sensor, a second sensor, a wave speed tester and a hoisting mechanism for suspending and fixing a rock-soil core sample; the signal generating module is electrically connected with the steady-state vibration exciter, and the steady-state vibration exciter is mechanically connected with the rock-soil core sample through a connecting rod and a connector; the first sensor and the second sensor are respectively arranged at different positions on the surface of the rock-soil core sample. The wave speed tester is electrically connected with the first sensor and the second sensor respectively. According to the steady-state vibration exciter, exciting force is applied to the rock-soil core sample through the connecting rod and the connector, the exciting direction of the vibration exciter can be adjusted by adjusting the placing mode of the vibration exciter, and the direction of the exciting force applied to the rock-soil core sample is changed by correspondingly adjusting the direction of the connecting rod, so that the accuracy of a wave speed test result is improved.
Description
Technical Field
The invention belongs to the technical field of engineering test, and particularly relates to a rock-soil core sample wave velocity test system and method.
Background
The propagation speed of elastic waves (shear waves and compression waves) in rock and soil is an important physical parameter of the rock and soil, and can reflect the engineering mechanical properties.
The compression wave speed can be conveniently and accurately measured by a laboratory through an acoustic wave transmission method by using piezoelectric ceramic acoustic wave transducers and acoustic wave instruments which are arranged at two ends of a rock core sample. When the shear wave speed is measured by the same method, the used acoustic wave transducer has special requirements on the piezoelectric ceramic element, has higher difficulty in processing and has difficult guarantee of the test effect; meanwhile, as the shear wave is not the first head wave, the influence of the compression wave is difficult to eliminate during testing, a certain error exists in the first arrival time of the shear wave according to the test waveform, and a certain error exists in the shear wave speed calculated according to the first arrival time. And the sonic transmission method is mostly used for testing the wave velocity of rock samples, and has a certain problem in application to the soil core samples.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a rock-soil core sample wave velocity testing system and a rock-soil core sample wave velocity testing method, which are used for solving the problem that a wave velocity testing result obtained by an acoustic wave transmission method in the prior art is inaccurate.
A first aspect of an embodiment of the present invention provides a rock core sample wave velocity testing system, including: the device comprises a signal generation module, a wave speed tester, a steady-state vibration exciter, a connecting rod, a connector, a first sensor, a second sensor and a hoisting mechanism for suspending and fixing a rock-soil core sample;
the signal generation module is electrically connected with the steady-state vibration exciter, the steady-state vibration exciter is mechanically connected with the first end of the connecting rod, the second end of the connecting rod is mechanically connected with the connector, the connector is mechanically connected with the rock-soil core sample, and the wave speed tester is electrically connected with the first sensor and the second sensor respectively; when in use, the first sensor and the second sensor are respectively arranged at different positions on the surface of the rock core sample.
A second aspect of the embodiment of the invention provides a rock-soil core sample wave velocity testing method, which comprises the following steps:
generating a sine wave signal through the signal generating module and sending the sine wave signal to the steady-state vibration exciter;
generating periodic exciting force according to the sine wave signal through the steady-state vibration exciter, and enabling the periodic exciting force to sequentially act on the end face of the rock-soil core sample through the connecting rod and the connector;
respectively acquiring vibration waveforms of corresponding positions of the rock-soil core sample through the first sensor and the second sensor;
and acquiring the vibration waveforms acquired by the first sensor and the vibration waveforms acquired by the second sensor through the wave speed tester, and calculating the propagation speed of waves in the rock-soil core sample according to the vibration waveforms acquired by the first sensor and the vibration waveforms acquired by the second sensor.
The rock core sample wave velocity testing system provided by the embodiment of the invention comprises: the device comprises a signal generation module, a steady-state vibration exciter, a connecting rod, a connector, a first sensor, a second sensor and a hoisting mechanism for suspending and fixing a rock-soil core sample; the signal generation module is electrically connected with the steady-state vibration exciter, the steady-state vibration exciter is mechanically connected with the first end of the connecting rod, the second end of the connecting rod is mechanically connected with the connector, and the connector is mechanically connected with the rock-soil core sample; the first sensor and the second sensor are respectively arranged at different positions on the surface of the rock-soil core sample, and the wave speed tester is respectively and electrically connected with the first sensor and the second sensor. The steady-state vibration exciter of the embodiment applies the exciting force to the rock-soil core sample through the connecting rod and the connector, the exciting direction of the vibration exciter can be adjusted by adjusting the placing mode of the vibration exciter, and the direction of the exciting force applied to the rock-soil core sample is changed by correspondingly adjusting the direction of the connecting rod, so that the influence of compression waves in the shear wave test is avoided, and the accuracy of the wave speed test result is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a rock core sample wave velocity test system in shear wave testing according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a rock core sample wave velocity test system in a compressional wave test according to an embodiment of the present invention;
FIG. 3 is a schematic flow chart of an exemplary method for testing the wave velocity of a core sample of rock and soil according to an embodiment of the present invention;
FIG. 4 is a schematic flow chart of an exemplary method for testing the wave velocity of a core sample of rock and soil according to an embodiment of the present invention;
FIG. 5 is a schematic flow chart of the step S304 in FIG. 3 according to an embodiment of the present invention;
fig. 6 is a schematic flow chart of S503 in fig. 5 according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
The term "comprising" in the description of the invention and the claims and in the above figures and any variants thereof is intended to cover a non-exclusive inclusion. For example, a process, method, or system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed but may optionally include additional steps or elements not listed or inherent to such process, method, article, or apparatus. Furthermore, the terms "first," "second," and "third," etc. are used for distinguishing between different objects and not for describing a particular sequential order.
In order to illustrate the technical scheme of the invention, the following description is made by specific examples.
Example 1:
fig. 1 shows a schematic structural diagram of a rock core sample wave velocity test system, and the rock core sample wave velocity test system shown in fig. 1 includes: the device comprises a signal generation module 10, a wave speed tester 50, a steady-state vibration exciter 20, a connecting rod 30, a connector 40, a first sensor 81, a second sensor 82 and a hoisting mechanism for suspending and fixing a rock-soil core sample 60;
the signal generating module 10 is electrically connected with the steady-state vibration exciter 20, the steady-state vibration exciter 20 is mechanically connected with the first end of the connecting rod 30, the second end of the connecting rod 30 is mechanically connected with the connector 40, the connector 40 is mechanically connected with the rock core sample 60, and the wave velocity tester 50 is electrically connected with the first sensor 81 and the second sensor 82 respectively; in use, the first sensor 81 and the second sensor 82 are disposed at different locations on the surface of the core 60.
In this embodiment, all devices of the core sample wave speed testing system are placed on a test bench, the signal generating module 10 includes a signal generator and a power amplifier, a sine wave signal is generated by the signal generator and sent to the power amplifier, the power amplifier amplifies the sine wave signal generated by the signal generator and drives the vibration exciter to generate corresponding exciting force, the vibration exciter can change the exciting direction so as to generate exciting force perpendicular to the axis of the core sample and exciting force parallel to the axis of the core sample, the exciting force is applied to one end face of the core sample 60 through a connecting mechanism, a first sensor 81 and a second sensor 82 can be arranged on the outer circumferential face of the core sample 60, and vibration waveforms of corresponding positions of the core sample 60 are collected through the sensors, so that wave speed calculation is performed according to the change of the phase of the vibration waveforms.
In this embodiment, the steady-state exciter 20 preferably selects a high-frequency steady-state exciter.
In the present embodiment, the signal generating module 10 is connected to the vibration exciter by a multicore shielded cable, and similarly, the wave velocity tester 50 is connected to the first sensor 81 and the second sensor 82 by a multicore shielded cable.
According to the vibration exciter, the vibration exciting force acts on the rock-soil core sample through the connecting rod and the connector, the vibration exciting direction of the vibration exciter can be adjusted by adjusting the placement mode of the vibration exciter, and the direction of the vibration exciting force acting on the rock-soil core sample is changed by correspondingly adjusting the direction of the connecting rod, so that the influence of compression waves in shear wave test is avoided, and the accuracy of a wave speed test result is improved.
In one embodiment, the core 60 is cylindrical, the connector 40 is connected to an end surface of the core 60, and the center of the connector 40 is located on an extension of the central axis of the core 60.
As shown in fig. 2, the core 60 is first manufactured into a regular cylinder, so that two end faces of the cylinder are parallel, perpendicular to the central axis of the core and smooth, and the length of the core 60 is generally not less than 30cm; the connector 40 is connected to one end face of the core 60 by an adhesive such that the connector 40 is centered on an extension of the central axis of the core 60. The core 60 with the connector 40 is suspended so that the central axis of the core 60 remains horizontal.
In one embodiment, when the excitation direction of the steady-state exciter is consistent with the central axis direction of the rock core sample, the second end of the connecting rod 30 is connected with the end face central hole of the connector 40, and the central axis of the connecting rod 30 and the central axis of the connector 40 are located on the same straight line.
In one embodiment, when the excitation direction of the steady-state exciter is perpendicular to the central axis direction of the rock core sample, the second end of the connecting rod 30 is connected to the outer circumferential surface of the connector 40, and the central axis of the connecting rod 30 is perpendicular to the central axis of the connector 40 and intersects with the central axis extension line of the connector 40.
As shown in fig. 1 and 2, in the present embodiment, during the shear wave velocity test, the steady-state vibration exciter is vertically placed, the vibration exciting direction of the steady-state vibration exciter is vertical, and the connecting rod 30 is fixedly connected with the edge of the connector 40 through bolts. Specifically, the connecting rod is in a vertical state, the second end of the connecting rod 30 is connected with the bottom center of the outer circumferential surface of the connector 40, and the axis extension line of the connecting rod 30 passes through the center of the connector 40; when the compression wave speed is tested, the steady-state vibration exciter is horizontally placed, the vibration exciting direction of the steady-state vibration exciter is horizontal, the connecting rod 30 is horizontally connected with the end face center hole of the connector 40 through bolts, and the central axis of the connecting rod 30, the central axis of the connector 40 and the central axis of the rock core sample 60 are on the same straight line.
In one embodiment, the sensitivity direction of the first sensor 81 and the sensitivity direction of the second sensor 82 are the same as the excitation direction of the exciter, and the connection line between the first sensor and the second sensor is parallel to the central axis of the rock core sample.
In the embodiment, the sensor is a piezoelectric acceleration sensor with small volume, light weight, high sensitivity and wide measurement frequency band. The rock core sample test requires higher vibration frequency, and the sensor needs to have wider frequency band, so that the piezoelectric acceleration sensor can meet the test requirement more easily. The first sensor 81 and the second sensor 82 are respectively firmly adhered to one side of the rock-soil core sample 60 by using an adhesive, the connecting lines of the two sensors are parallel to the axis of the core sample, and the sensitivity direction of the sensors is parallel to the excitation direction of the vibration exciter, namely, when the shear wave speed is tested, the sensitivity direction is perpendicular to the central axis of the rock-soil core sample 60, and the sensitivity direction is perpendicularly intersected with the central axis of the rock-soil core sample 60; the direction of sensitivity is parallel to the central axis of the core 60 during compressional wave velocity testing.
In one embodiment, the hoisting mechanism comprises a vertical rod 71 vertically arranged on the test bed, a cross rod 72 vertically connected with the vertical rod 71, and a connecting rope 73 with one end fixedly connected with the cross rod 72 and the other end connected with the rock core sample 60 and enabling the central axis of the rock core sample 60 to be in a horizontal direction.
In this embodiment, the cross bar 72 is vertically connected to the top end of the vertical bar 71, and the connecting ropes 73 include two connecting ropes 73, so that the central axis of the cylindrical core sample 60 can be kept horizontal by adjusting the lengths of the two connecting ropes 73. Specifically, the connection cord 73 may be a rubber cord. The rubber rope is used as a connecting material of the rock core sample 60 and the test bed, so that high-frequency vibration transmitted along the test bed can be isolated, and interference signals during testing can be reduced.
In one embodiment, the distance between the first sensor 81 and the second sensor 82 is greater than 150mm.
In one embodiment, the exciter comprises a high frequency steady state exciter.
As shown in fig. 3, fig. 3 shows a flow of implementation of a method for testing a core sample wave velocity according to an embodiment of the present invention, and the process is described in detail as follows:
s301: generating a sine wave signal by the signal generating module 10 and transmitting the sine wave signal to the steady-state vibration exciter 20;
s302: generating a periodic exciting force according to the sine wave signal through the steady-state exciter 20, and enabling the periodic exciting force to sequentially act on the end face of the rock-soil core sample 60 through the connecting rod 30 and the connector 40;
s303: respectively acquiring vibration waveforms of corresponding positions of the rock-soil core sample 60 through the first sensor 81 and the second sensor 82;
s304: the vibration waveform collected by the first sensor 81 and the vibration waveform collected by the second sensor 82 are obtained by the wave velocity tester 50, and the propagation velocity of the wave in the rock core sample 60 is calculated according to the vibration waveform collected by the first sensor 81 and the vibration waveform collected by the second sensor 82.
In this embodiment, during testing, the signal generator is turned on first, the sine wave signal with appropriate frequency is selected, the power amplifier is turned on, the driving signal is provided to the steady-state vibration exciter 20 after preheating, the vibration head of the steady-state vibration exciter 20 generates periodic reciprocating motion, and the motion frequency is the signal frequency set by the signal generator. The steady-state vibration exciter 20 applies periodic vibration exciting force to one end of the rock-soil core sample 60 through the connecting rod 30 and the connector 40, so that the end surface of the rock-soil core sample 60 connected with the connector 40 generates periodic vibration, and the vibration direction is consistent with the vibration exciting direction of the vibration exciter.
As shown in fig. 1, during shear wave velocity testing, the vibration direction is perpendicular to the central axis of the core sample 60; as shown in fig. 2, the direction of vibration is parallel to the central axis of the core 60 during the compressional wave velocity test. The vibration of the end face of the rock core sample 60 propagates along the axial direction of the core sample to form fluctuation, and shear waves are generated when the vibration direction is perpendicular to the propagation direction; when the vibration direction matches the propagation direction, a compression wave is generated. The shear wave and the compression wave can be received by the sensor, and the propagation speed of the wave in the rock core sample 60 can be calculated by using the distance between the two sensors and the phase time difference between the two vibration waveforms received by the sensor.
As shown in fig. 4, in one embodiment of the present invention, before S301, fig. 4 shows an exemplary implementation flow of the present embodiment, which includes:
s401: acquiring a distance between the first sensor 81 and the second sensor 82;
s402: the optimal excitation frequency of the sine wave signal is estimated according to the rock-soil characteristics of the rock-soil core sample 60 and the distance between the first sensor 81 and the second sensor 82.
In this embodiment, before the test, the range values of the shear wave velocity and the compression wave velocity of the core rock sample 60 are estimated according to the lithology thereof, and the appropriate excitation frequency is selected in combination with the distance between the first sensor 81 and the second sensor 82. For example, the shear wave velocity test of the rock core sample is carried out, the estimated shear wave velocity is about 1800m/s, the distance between the first sensor 81 and the second sensor 82 is 18cm, the propagation time of the shear wave between the two sensors is 100 mu s, if the phase difference of the vibration waveforms of the two sensor positions is not smaller than pi/6 (the phase difference is too small, the test precision is reduced), the excitation period used in the test is not larger than 1200 mu s, and the excitation frequency is not smaller than 0.83kHz.
In this embodiment, after the optimal excitation frequency is obtained, the frequency sweep is performed from the optimal excitation frequency, and the vibration waveform is observed, so that the frequency with the best test effect is further obtained, and the vibration waveforms of the two test sections of the rock core sample 60 are recorded at the frequency.
As shown in fig. 5, in one embodiment of the present invention, fig. 5 shows a specific implementation flow of S304 in fig. 3, which includes:
s501: calculating a time difference of wave propagation between the first sensor 81 and the second sensor 82 according to the vibration waveform acquired by the first sensor 81 and the vibration waveform acquired by the second sensor 82;
s502: acquiring a distance between the first sensor 81 and the second sensor 82 as a sensor pitch;
s503: from the sensor spacing and the time difference between the first sensor 81 and the second sensor 82, the propagation velocity of the wave in the core sample 60 is calculated.
In the present embodiment, the distance between the first sensor and the second sensor is the distance of the two sensors in the horizontal direction. The first sensor 81 and the second sensor 82 may be disposed at different positions on the same horizontal line of the outer circumferential surface of the core sample 60, and then the distance between the first sensor 81 and the second sensor 82 may be measured as the sensor pitch. And determines the propagation velocity of the wave in the core sample 60 based on the sensor spacing and the waveform time difference.
As shown in fig. 6, in one embodiment of the present invention, fig. 6 shows that the specific implementation procedure of S501 in fig. 5 includes:
s601: determining a phase difference between the vibration waveform acquired by the first sensor 81 and the vibration waveform acquired by the second sensor 82 according to a waveform shifting method or a signal correlation analysis method;
s602: from the phase difference of the vibration waveform acquired by the first sensor 81 and the vibration waveform acquired by the second sensor 82, the time difference of the wave traveling between the first sensor 81 and the second sensor 82 is calculated.
In this embodiment, the specific implementation procedure of S601 may include:
first, in the normal working state of the vibration exciter, vibration waveforms of two sensor positions are collected simultaneously, the vibration waveform collected by the first sensor 81 is used as a first vibration waveform, and the vibration waveform collected by the second sensor 82 is used as a second vibration waveform. And then, according to a waveform moving method or a signal correlation analysis method, moving the second vibration waveform by taking the first peak of the first vibration waveform as a reference, so that the first vibration waveform and the second vibration waveform are overlapped, and obtaining the phase difference of the first vibration waveform and the second vibration waveform. The frequencies of the first vibration waveform and the second vibration waveform are the same, and thus the time difference of the waves between the first sensor 81 and the second sensor 82 can be calculated from the phase difference of the two waveforms.
In one embodiment of the present invention, the specific implementation procedure of S503 further includes:
calculation ofObtaining the propagation velocity of waves in the core sample 60; where v denotes the propagation velocity of the wave in the core 60, L denotes the sensor pitch, Δt denotes the time difference between the first sensor 81 and the second sensor 82. When the exciting direction is perpendicular to the central axis of the rock core sample, the obtained wave speed is the shear wave speed v s The method comprises the steps of carrying out a first treatment on the surface of the When the exciting direction is consistent with the central axis of the rock core sample, the obtained wave speed is the compression wave speed v p 。
The shear wave velocity and the compressional wave velocity of the core sample 60 can be calculated by the above method.
As can be seen from the above embodiment, a high-frequency steady-state vibration exciter is adopted to excite high-frequency vibration perpendicular to and parallel to the central axis of the core sample at one end of the core sample 60, the vibration propagates along the central axis direction of the core sample 60 to form shear waves and compression waves, when the excitation direction is perpendicular to the central axis direction of the core sample, the vibration direction is perpendicular to the wave propagation direction, the shear wave energy is dominant, the interference of the compression waves is suppressed to the maximum extent, the first sensor 81 and the second sensor 82 with the sensitivity direction consistent with the excitation direction are used to receive the vibration signals respectively, and the reliability of the shear wave measurement signals and the reliability of the test results are ensured; when the exciting direction is parallel to the central axis direction of the core sample, the vibration direction is consistent with the wave propagation direction, the compression wave energy is dominant, the first sensor 81 and the second sensor 82 with the sensitivity direction consistent with the exciting direction are utilized to respectively receive the vibration signals, and the reliability of the compression wave measurement signals and the reliability of the test results are ensured. Secondly, two rubber ropes are used as connecting materials of the rock core sample 60 and the test bed, high-frequency vibration transmitted along the test bed can be isolated, and interference signals during testing can be reduced. The excitation frequency is changed through the signal generator, the frequency sweep test is carried out, the frequency range with good test effect is searched, the frequency range with good effect can be tested, the rock-soil core sample 60 vibrates with larger amplitude, and the received signal has higher signal-to-noise ratio. For two sine waves with the same frequency, the phase difference of the two waveforms can be accurately measured by using a mathematical tool of signal correlation analysis, so that the time difference of wave propagation between two sensors is obtained, and the shear wave speed and the compression wave speed of the rock core sample 60 are conveniently calculated.
The steps in the method of the embodiment of the invention can be sequentially adjusted, combined and deleted according to actual needs.
The modules or units in the system of the embodiment of the invention can be combined, divided and deleted according to actual needs.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention.
Claims (7)
1. A geotechnical core sample wave velocity testing system, comprising: the device comprises a signal generation module, a wave speed tester, a steady-state vibration exciter, a connecting rod, a connector, a first sensor, a second sensor and a hoisting mechanism for suspending and fixing a rock-soil core sample;
the signal generation module is electrically connected with the steady-state vibration exciter, the steady-state vibration exciter is mechanically connected with the first end of the connecting rod, the second end of the connecting rod is mechanically connected with the connector, the connector is mechanically connected with the rock-soil core sample, and the wave speed tester is electrically connected with the first sensor and the second sensor respectively; when in use, the first sensor and the second sensor are respectively arranged at different positions on the surface of the rock core sample;
the rock core sample is cylindrical; the connector is connected with the end face of the rock-soil core sample, and the center of the connector is positioned on the extension line of the central axis of the rock-soil core sample;
when the excitation direction of the steady-state vibration exciter is consistent with the central axis direction of the rock-soil core sample, the second end of the connecting rod is connected with the end face central hole of the connector, and the central axis of the connecting rod and the central axis of the connector are positioned on the same straight line;
the sensitivity direction of the first sensor and the sensitivity direction of the second sensor are the same as the excitation direction of the vibration exciter, and the connecting line of the first sensor and the second sensor is parallel to the central axis of the rock-soil core sample.
2. The rock core sample wave velocity test system of claim 1, wherein when the excitation direction of the steady-state exciter is perpendicular to the rock core sample axis direction, the second end of the connecting rod is connected with the outer circumferential surface of the connector, and the central axis of the connecting rod is perpendicular to the central axis of the connector.
3. A method of testing a core sample wave velocity based on the core sample wave velocity testing system of any one of claims 1 to 2, comprising:
generating a sine wave signal through a signal generating module, and transmitting the sine wave signal to a steady-state vibration exciter;
generating periodic exciting force according to the sine wave signal through the steady-state vibration exciter, and enabling the periodic exciting force to act on the end face of the rock-soil core sample through a connecting rod and a connector in sequence;
respectively acquiring vibration waveforms of corresponding positions of the rock-soil core sample through a first sensor and a second sensor;
and acquiring the vibration waveforms acquired by the first sensor and the vibration waveforms acquired by the second sensor through a wave speed tester, and calculating the propagation speed of waves in the rock-soil core sample according to the vibration waveforms acquired by the first sensor and the vibration waveforms acquired by the second sensor.
4. A method of testing the wave velocity of a core sample as defined in claim 3, further comprising, prior to the signal generation module generating a sine wave signal:
acquiring a distance between the first sensor and the second sensor;
and estimating the optimal excitation frequency of the sine wave signal according to the rock-soil characteristics of the rock-soil core sample and the distance between the first sensor and the second sensor.
5. A method of testing the wave velocity of a core sample of rock and soil according to claim 3, wherein said calculating the propagation velocity of waves in said core sample of rock and soil from the vibration waveforms collected by said first sensor and said second sensor comprises:
calculating the time difference of wave propagation between the first sensor and the second sensor according to the vibration waveform acquired by the first sensor and the vibration waveform acquired by the second sensor;
acquiring the distance between the first sensor and the second sensor as a sensor distance;
and calculating the propagation speed of the wave in the rock-soil core sample according to the sensor spacing and the time difference between the first sensor and the second sensor.
6. The method of testing the wave velocity of a core sample of rock and soil according to claim 5, wherein calculating the time difference of wave propagation between the first sensor and the second sensor based on the vibration waveform collected by the first sensor and the vibration waveform collected by the second sensor comprises:
determining the phase difference of the vibration waveform acquired by the first sensor and the vibration waveform acquired by the second sensor according to a waveform moving method or a signal correlation analysis method;
and calculating the time difference of wave propagation between the first sensor and the second sensor according to the phase difference of the vibration waveform acquired by the first sensor and the vibration waveform acquired by the second sensor.
7. The method of testing the wave velocity of a core sample according to claim 5, wherein calculating the wave propagation velocity in the core sample based on the sensor pitch and the time difference between the first sensor and the second sensor comprises:
calculation ofObtaining the propagation speed of waves in the rock-soil core sample; where v denotes the propagation velocity of the wave in the core sample, L denotes the sensor pitch, Δt denotes the time difference between the first sensor and the second sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201910717014.8A CN110333295B (en) | 2019-08-05 | 2019-08-05 | Rock-soil core sample wave speed testing system and method |
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