KR101123791B1 - Apparatus for measuring soil disturbance in soil sampler by using shear wave and Method of measuring the same - Google Patents

Abstract

Provided are an apparatus and a measuring method for disturbance of a sample in a soil sampler using shear waves. The measuring device may include: a soil sampler including a tube receiving a soil sample to be inserted into the ground and being tested, a plurality of outgoing transducers installed in the tube, and a receiving transducer; A signal generator for applying an electrical signal to the outgoing transducer; Characterized in that the detection unit to determine the shear stiffness and the degree of disturbance of the sample by finding the velocity of the shear wave passed through the sample, the present invention made as described above by measuring the velocity of the shear wave passing through the sample It is possible to grasp the disturbance state and the overall homogeneity of the, and to determine the change characteristics of the disturbance state before and after the movement of the sample, and the layer standing classification by measuring the shear wave velocity by location.

Description

Apparatus for measuring soil disturbance in soil sampler by using shear wave and Method of measuring the same}

The present invention relates to an apparatus for measuring the disturbance degree of a sample in a soil sampler using a shear wave. More particularly, the present invention relates to a disturbance degree that enables change in the disturbance state of a sample and a layer standing classification by using a shear wave. It relates to a device and a measuring method.

In recent years, as the development of the whole country continued, the construction work on the civil construction environment-related facilities, etc., was no longer possible to be carried out only in good ground. In other words, more and more cases have to be carried out in the adverse conditions that were excluded when selecting the location of the conventional construction, such as coastal, mountainous, rocky land, garbage landfill, near the existing structure of downtown.

Accordingly, in order to construct the structure safely and economically, it is required to acquire and evaluate the ground information through accurate ground survey. The purpose of these surveys is to prepare the basic data necessary for the construction and maintenance of the structure as safely and economically as possible, such as the characteristics of the ground and the condition of the ground and the calculation of settlement.

The above-mentioned ground survey method is generally divided into field test and indoor test. The field test is a process of obtaining a ground internal situation or other necessary information by installing a test device such as an inspection probe on the ground. In addition, the indoor test is to obtain a sample that can represent the characteristics of the ground, transport it to the laboratory and perform various necessary tests and analysis in the laboratory.

The most important thing when taking a sample soil for the indoor test is to preserve the field characteristics as much as possible. That is, when sampling the sample, the sample is taken as it is on the ground so that the internal structure, pressure, or humidity of the sample does not change.

However, no matter how careful sampling is, sample disturbances and changes in moisture content during sampling and transport cannot be avoided, and thus samples cannot be obtained in the ideal state (the state before they are buried in the ground). In other words, the sample collected in the tube sampler is somewhat disturbed. For this reason, when the tube is inserted, disturbance occurs due to the friction between the soil and the tube wall surface, so it is necessary to measure the disturbance during the collection. Before performing the indoor test, the disturbance degree of the collected sample is first identified and various tests and analysis are taken into account. Should be performed. Through the measurement of such disturbances, the internal state of the sample can be known, and soil settling or collapse can be predicted.

However, in the conventional disturbance measuring device, most of the measurement accuracy is inferior, and it is difficult to obtain necessary information or to measure accurate disturbance because it is not able to grasp the change of disturbance by position in the sampler or the homogeneity of the sample. .

The first technical problem to be achieved by the present invention is to determine the disturbance state and the overall homogeneity of the sample through the measurement of the velocity of the shear wave passing through the sample, it is possible to grasp the change characteristics of the disturbed state, as well as measuring the shear wave velocity by location It is to provide an apparatus for measuring the disturbance of the sample in the soil sampler that can be separated through the layer standing.

The second technical problem to be achieved by the present invention is to provide a method for measuring the disturbance degree of the sample in the soil sampler using the measuring device.

The present invention to achieve the first technical problem,

The tube which takes the form of a pipe having a constant diameter and is inserted into the ground to receive the soil sample to be tested therein, which is installed in the tube and arranged in the longitudinal direction and receives electrical signals provided from the outside to the inside of the tube A plurality of outgoing transducers for transmitting a shear wave to the outgoing transducer and one-to-one correspondence to the outgoing transducers are mounted on opposite sides of the outgoing transducers with the central axis of the tube interposed therebetween, and receive the shear wave signals generated from the outgoing transducers and passed through the sample. A small sampler including a receiving transducer; A signal generator for applying an electrical signal to the outgoing transducer; In addition to the signal generator and receiving a shear wave signal received by the receiving transducer in the soil sampler including a detector for detecting the shear stiffness and disturbance degree of the sample by the operator to determine the velocity of the shear wave passing through the sample Provide a device for measuring the disturbance of the sample.

According to one embodiment of the invention, the outgoing transducer; A cylindrical member having a male thread formed on its outer circumferential surface, and a screw case coupled to the tube, and an outgoing sensor embedded in the screw case, connected to the signal generator through a cable, and generating a shear wave by an electrical signal of the signal generator. For example, a vendor element, and a receiving transducer; A cylindrical member having a male thread formed on its outer circumferential surface, and a screw case coupled to the tube, and a receiving sensor installed inside the screw case and receiving a shear wave signal generated from the outgoing sensor of the outgoing transducer and sending it to a detector through a cable. (Eg, a vendor element).

In addition, the outer peripheral surface of the tube extending in the longitudinal direction of the tube and having a predetermined cross-section between the tube is fixed to the support rod is fixed, the screw case of the outgoing transducer and the screw case of the receiving transducer is fixed to the Penetrating the support rod and the tube, but screwed to the support rod, the outer portion of each of the support rod may be equipped with a cover for protecting the cable connected to each transducer.

The present invention to achieve the second technical problem,

(a) a tube having a constant diameter and receiving a soil sample to be inserted into the ground to be tested therein; and a plurality of tubes installed in the tube to receive a plurality of electric signals provided from the outside. A plurality of outgoing transducers for transmitting shear waves into the inside of the tube and one-to-one correspondence to the outgoing transducers, which are mounted on opposite sides of the outgoing transducers with the central axis of the tube interposed therebetween, generated from the outgoing transducers and passing through the sample. A sampling step of injecting a soil sampler including a receiving transducer receiving a shear wave signal into the ground and collecting a soil sample to be tested inside the tube;

(b) a shear wave transmission step of applying an electrical signal to the outgoing transducer to cause the outgoing transducer to transmit a shear wave inside the sample;

(c) a shear wave receiving and processing step of receiving a shear wave generated through the shear wave transmitting step through a receiving transducer, amplifying and filtering the shear wave; And

(d) it provides a method of measuring the disturbance of the sample in the small sampler using a shear wave including an analysis step of analyzing the signal obtained through the processing step to find the shear stiffness and the degree of disturbance of the sample passed through the shear wave.

According to an embodiment of the present invention, the transmitting transducer and the receiving transducer are arranged in the longitudinal direction of the tube which is vertically introduced into the ground to grasp the variation of the shear wave velocity for each depth of the sample sampled in the tube. It is characterized by.

According to the present invention, the disturbance state and the overall homogeneity of the sample can be grasped by measuring the velocity of the shear wave passing through the sample, and the change characteristic of the disturbance state before and after the movement of the sample can be grasped, as well as the position. It is also possible to distinguish strata by measuring the shear wave velocity of each star.

Hereinafter, one embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the overall configuration of the disturbance degree measuring device of the sample in the soil sampler using a shear wave according to an embodiment of the present invention, Figure 2 is a partial excerpt showing the excitation sample shown in FIG. 3 is an exploded perspective view, and FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1.

Referring to the drawings, the apparatus for measuring the disturbance of the sample in the small sampler using the shear wave according to the present embodiment, the tube 10 and the length of the tube 10 having a vertical diameter is vertically introduced into the ground of the region to be sampled A plurality of outgoing transducers 16 arranged along a direction, and a plurality of outgoing transducers positioned opposite to the outgoing transducer 16 about a central axis of the tube 10 and corresponding one-to-one to the outgoing transducer 16 ( A small sampler 20 including a signal source 18, a signal generator 30 for applying an electric signal to the source transducer 16, and a sense of the signal received by the received transducer 18 Shear wave 32 which performs the removal and amplification, and is connected to the signal generator 30 and the signal processing unit 32 and passed between the transmitting transducer 16 and the receiving transducer 18. To determine the speed of An oscilloscope 34 is provided to allow the determination of shear stiffness and disturbance.

First, the tube 10 constituting the small sampler 20 is a hollow pipe having a diameter D and extending in the longitudinal direction. The tube 10 is connected to an external holder (not shown) and is a member that is vertically penetrated into the ground, and a blade portion 10a is provided at the lower end to facilitate penetration. The blade portion 10a is a sharply processed portion of the lower end of the tube 10 and pushes the soil around the outside during penetration.

In addition, the support rod 12 is fixed to the outer peripheral surface of the tube (10). The support rod 12 is a member of a predetermined cross-section which is welded to the outer circumferential surface of the tube 10 but extends in parallel in the longitudinal direction of the tube 10. The support rod 12 is for firmly fixing the transducers 16 and 18 with respect to the tube 10 and is located opposite to each other with the tube 10 in the center.

In addition, each of the supporting rods 12 is provided with a female screw hole 12a, and a through hole 10b is provided in the tube 10 at the portion where the female screw hole 12a is formed. It goes without saying that the female screw hole 12a and the through hole 10b have the same center. A plurality of female screw holes 12a are disposed along the longitudinal direction of the supporting rod 12, and each of the female screw holes 12a is screwed with the transmitting transducer 16 or the receiving transducer 18. The number of the female screw holes 12a is not particularly limited and may be provided up to 35 at 2 cm intervals, for example. In the exemplary embodiment of the present invention shown in FIG. 1, the number of the female threaded holes 12a is 6 for each support rod 12, the distance between the holes is set to 100 mm, and the total length of the tube 10 is 1000 mm. And, the diameter of the tube 10 is 76mm, the length of the support rod 12 is shown as 715mm, but is not limited thereto.

The cover 14 is fixed to the outside of each of the support rods 12. The cover 14 is a rod-shaped member having a cross-sectional shape of a c-shape is fixed to the outside of the support rod 12 to provide a space portion 15. The space portion 15 is utilized to accommodate the cable 16a to be described later.

On the other hand, each of the transmission transducer 16, the screw case 16c for screwing into the female screw hole (12a), and the inside of the screw case (16c), the front end of which is mounted inside the tube 10 Outgoing sensor 16b protruding toward the side, and the cable connected to the signal generator 30 is connected to the outgoing sensor 16b in the screw case (16c) and extends to the outside in a state located in the inner space 15 ( 16a). The cable 16a transmits the electric signal output from the signal generator 30 to the transmitting sensor 16b so that the transmitting sensor 6b generates a shear wave.

In addition, the receiving transducer 18 is provided with a case screw 18c for screwing into the female screw hole 12a, and the inside of the case screw 18c, and the tip of the receiving transducer 18 faces the transmitting transducer 16. It is composed of a protruding receiving sensor 18b and a cable 18a extending outward while being connected to the receiving sensor 18b in the case screw 18c and connected to the signal processing unit 32. The receiving sensor 18b receives the shear wave generated by the outgoing transducer 16 and passes through the sample A, converts the shear wave into an electrical signal, and transmits the signal to the signal processing unit 32 through the cable 18a.

The transmitting sensor 16b and the receiving sensor 18b may be bender elements, and may be used without any limitation as long as they are commonly used in almost all soil test apparatuses including soil compaction and triaxial testing.

In particular, the signal generator 30 may give an electrical signal to all the outgoing transducers 16, or may send a signal only to the outgoing transducers 16 selected for the purpose of the test. Since the reception transducer 18 corresponds to the transmission transducer 16 one-to-one, it operates in response to the transmission transducer generating the shear wave by receiving a signal from the signal generator 30.

4 is a view illustrating a method of measuring the disturbance degree of the sample in the soil sampler using the shear wave according to an embodiment of the present invention.

Basically, in the method of measuring the disturbance of the sample in the small sampler according to the present embodiment, the shear wave is passed through the sample A sampled in the small sampler 20 (in the radial direction of the tube 10) so that the shear wave is the sample A. ), Which has a basic principle of determining the rate of perturbation of the sample and determining the degree of disturbance of the sample, based on the sampling rate (100), the shear wave transmitting step (102), the shear wave receiving and processing step (104), and An analysis step 106 is included. The velocity (V) of the shear wave is a value obtained by dividing the distance (L) between the transducers by the travel time (t) of the shear wave.

The sampling step 100 is a step of vertically injecting the tube 10 into the ground of the region of interest with the transducers 16 and 18 installed on the tube 10 and the cables 16a and 18a connected. Soil is sampled into the tube 10 as the tube 10 penetrates vertically. When collecting the soil sample through the tube 10, the disturbance of the sample (A) occurs due to the friction of the soil surface and the wall surface of the tube 10, this sampling step 100 using this apparatus The degree of disturbance of the sample in can be measured. In more detail, the method for measuring the disturbance degree of the sample is first introduced into the tube 10 so that the soil sample A enters the transducer installed at the lower end from the end of the tube, and then the shear wave is measured. Next, the tube 10 is further penetrated deeper, and then the sample A is introduced to the transducer provided thereafter, and the shear wave is measured again, and the tube 10 is further penetrated deeply. Measure the shear wave at the first transducer. That is, through such a process, it is possible to measure the degree of disturbance of the soil sample generated when the tube penetration through the shear wave velocity obtained by continuously measuring the shear wave in the process of moving the soil sample into the inside of the tube (10). .

On the other hand, the disturbance measuring apparatus according to the present invention can measure the disturbance degree in the process of moving the sample or the storage of the sample as well as the sampling process as described above.

The measurement of the shear wave will now be described in detail.

After the sample A is sampled in the tube 10, the shear wave emitting step 102 is performed, which operates the signal generator 30 to the desired or all outgoing transducers 16. The process of sending an electrical signal. The outgoing sensor 16b of the outgoing transducer 16 receiving the electric signal from the signal generator 30 generates a shear wave signal.

As described above, the shear wave generated in the outgoing transducer 16 passes through the sample A and reaches the opposite receiving transducer 18. The receiving transducer 18 receives the shear wave, converts it into an electrical signal, and sends the signal to the signal processing unit 32 through the cable 18a. The signal processing unit 32 removes the noise from the electrical signal received from the receiving transducer 18, amplifies it, and sends it to the oscilloscope 34. (Shear wave receiving and processing step 104)

Next, the analysis step 106 is followed through the oscilloscope. The analysis step 106 is to analyze the signal obtained through the shear wave reception and processing step 104 to determine the rate at which the shear wave passed through the sample (A) and to find the shear stiffness and disturbance degree of the sample (A) based on this Step.

Next, in order to take out the tube 10 in a state where the sampling of the soil is completed and to transport the soil sampler 20 (with the sample A included), the tube 10 may not fall to the bottom of the tube 10. The bottom part should be blocked.

The application of a shear wave in the ground to determine the rate at which the shear wave passes through the ground, and to estimate the shear stiffness and disturbance of the ground based on the shear wave can be obtained using a method commonly known in the art. When this occurs, the phenomenon of the separation between the soil particles and particles occurs, the shear wave speed is reduced, this decrease in the shear wave speed means that the sampling soil disturbance is possible.

Figure 5 shows the results of measuring the shear wave for the sample in which the strata are separated using a disturbance measuring device of the sample in the soil sampler using the shear wave according to the present invention, the rate of the shear wave when the disturbance occurs, but in the case of Figure 5 The shear wave velocity is the slowest in the middle and is probably due to the stratification of the sample.

Figure 6 shows the shear wave measurement results according to the elapsed days after the sample was collected using a disturbance measuring device of the sample in the soil sampler using the shear wave according to the present invention. Referring to Figure 5, it can be seen that there is a difference in the shear wave according to the position of the sample in the tube, it can be distinguished through the strata, and with reference to Figure 6, as the time passes after the sample is collected and changes in the shear wave storage As the period gets longer, it can be confirmed that the change of the sample can be identified.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

1 is a view showing the overall configuration of a disturbance measuring device of a sample in a soil sampler using a shear wave according to an embodiment of the present invention.

2 is an exploded perspective view showing a partial extract of the small sampler shown in FIG.

3 is a cross-sectional view taken along the line III-III of FIG. 1.

4 is a view illustrating a method of measuring the disturbance degree of the sample in the soil sampler using the shear wave according to an embodiment of the present invention.

5 is a view showing the results of measuring the shear wave for the sample is separated by using a disturbance measuring device of the sample in the soil sampler using the shear wave according to the present invention.

6 is a graph showing the results of measuring the shear wave according to the elapsed days after the sampling using the apparatus for measuring the disturbance degree of the sample in the soil sampler using the shear wave according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: tube 10a: blade portion

12: support rod 12a: female thread hole

14: Cover 15: space part

16: Outgoing transducer 16a: Cable

16b: Outgoing sensor (bender element) 16c: Screw case

18: Receive Transducer 18a: Cable

18b: Receiver sensor (bender element) 18c: Case screw

20: small sampler 30: signal generator

32: signal processing part 34: oscilloscope

36: cable

Claims (6)

The tube which takes the form of a pipe having a constant diameter and is inserted into the ground to receive the soil sample to be tested therein, which is installed in the tube and arranged in the longitudinal direction and receives electrical signals provided from the outside to the inside of the tube A plurality of outgoing transducers for transmitting a shear wave to the outgoing transducer and one-to-one correspondence to the outgoing transducers are mounted on opposite sides of the outgoing transducers with the central axis of the tube interposed therebetween, and receive the shear wave signals generated from the outgoing transducers and passed through the sample. A small sampler including a receiving transducer; A signal generator for applying an electrical signal to the outgoing transducer; In addition to being connected to the signal generator, receiving a shear wave signal received by a receiving transducer, the speed of the shear wave passing through the sample sampled in the tube of the soil sampler can be determined to allow the operator to find the shear stiffness and disturbance of the sample. Disturbance measurement device of the sample in the soil sampler using a shear wave, characterized in that it comprises a detection unit. The method of claim 1, The outgoing transducer; A cylindrical member having a male screw thread formed on its outer circumferential surface, and a screw case coupled to the tube, and an outgoing sensor embedded in the screw case, connected to the signal generator through a cable, and generating a shear wave by an electrical signal of the signal generator. Disturbance measurement device of the sample in the soil sampler using a shear wave, characterized in that it comprises. The method of claim 1, The receiving transducer includes; A cylindrical member having a male thread formed on its outer circumferential surface, and a screw case coupled to the tube, and a receiving sensor installed inside the screw case and receiving a shear wave signal generated from the outgoing sensor of the outgoing transducer and sending it to a detector through a cable. Disturbance measurement apparatus of the sample in the soil sampler using a shear wave, characterized in that it comprises a. 3. The method of claim 2, On the outer circumferential surface of the tube is extended along the longitudinal direction of the tube is fixed to the support rod which is located on the opposite side with the tube between the fixed section, The screw case of the outgoing transducer and the screw case of the receiving transducer penetrate the support rod and the tube but screw the support rod, Outer portion of the support rod is a disturbance measuring device of the sample in the soil sampler using a shear wave, characterized in that the cover is mounted to protect the cable connected to each transducer. (a) take the form of a pipe having a constant diameter and receive a soil sample inside the soil to be tested and inserted therein; and installed in the tube to receive a plurality of electric signals provided from the outside arranged in the longitudinal direction A plurality of outgoing transducers for transmitting a shear wave to the inside of the tube, and a one-to-one correspondence to the outgoing transducers, which are mounted on opposite sides of the outgoing transducers with a central axis of the tube interposed therebetween and are generated from the outgoing transducers and passed through the sample. A sampling step of collecting soil samples to be tested in the tube by injecting a soil sampler including a receiving transducer receiving a signal into the ground; (b) a shear wave transmission step of applying an electrical signal to the outgoing transducer to cause the outgoing transducer to transmit a shear wave inside the sample; (c) a shear wave receiving and processing step of receiving a shear wave generated through the shear wave transmitting step through a receiving transducer, amplifying and filtering the shear wave; And (d) measuring the disturbance degree of the sample in the soil sampler using a shear wave, characterized in that it comprises a step of analyzing the signal obtained through the processing step to find the shear stiffness and disturbance of the sample passed the shear wave. The method of claim 5, The source transducer and the receiver transducer are arranged in the longitudinal direction of a tube which is vertically introduced into the ground, so that a sample of the shear wave using a shear wave, characterized in that it is possible to grasp the variation of the shear wave velocity for each depth of the sample sampled in the tube. How to measure the disturbance of my sample.

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