KR100860937B1 - Soft ground measuring device using bender element - Google Patents

Abstract

Disclosed is a soft ground measuring apparatus using a bender element capable of measuring a good shear wave signal according to continuous consolidation and stiffness evaluation using a bender element in a field. The present invention has a pile member that is formed in a constant length and mounted vertically to the tip of the mandrel or drilling machine. On one side of the pile member, a pair of horizontal members formed in a rectangular plate shape is hinged to each end so as to enable a predetermined movement in a state where they are arranged horizontally with respect to the pile member. Corresponding surfaces of the horizontal members are provided with a foot and a vibration member, respectively, for oscillating and receiving the vibration in the longitudinal direction. The soft ground measuring apparatus using the bender element configured as described above can measure high quality shear wave signals by improving contact with soil through the wide contact surface of the horizontal member when measuring shear wave signals by depth intruding into the soft ground. In addition, the vibration generated from the oscillation member by the gap formed by the gap between the pile member and each horizontal member by the hinge coupling minimizes the vibration reaching the oscillation member through the pile member, so that better measurement of the shear wave signal is possible.

Description

BURIED SENSORS FOR STIFFNESS MEASUREMENTS OF SOIL USING BENDER ELEMENTS}

1 is a perspective view of a soft ground measuring apparatus using a bender element according to a first embodiment of the present invention,

2 is a front view of the soft ground measuring apparatus using the bender element shown in FIG.

3A and 3B are cross-sectional views showing the oscillation member and the oscillation member shown in FIG. 1;

Figure 4 is a state of use of the soft ground measuring apparatus using a bender element according to the present invention,

5 is a perspective view of a soft ground measuring apparatus using a bender element according to a second embodiment of the present invention, and

6 is a perspective view of a soft ground measuring apparatus using a bender element according to a third embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

10: pile member 20,22: a pair of horizontal members

24: resonance pin 26: worn out

30: oscillation member 32: oscillation member

The present invention relates to a soft ground measuring apparatus using a bender element, and more particularly, soft ground using a bender element capable of measuring a good shear wave signal according to continuous consolidation and stiffness evaluation using the bender element in the field. It relates to a measuring device.

The plain area, which is 30% of Korea's land, is developed along with large river basins and coasts. These plains are made up of the most fragile strata that have not yet been entrusted to the fourth alluvial deposit.

In general, the engineering soft ground means that when the relative density of sand is 35% or less and N is 4 or less, the clay has a uniaxial compressive strength of 0.25㎏ / ㎠ or less. However, soft ground in the broad sense refers to the ground where the superstructure cannot be supported.

Recently, artificial grounds such as landfills are also included as soft grounds, and their range and application are also diversified. Such soft ground has problems such as lack of support and activity, excessive settlement, sub-friction, liquefaction phenomenon.

Therefore, field vane test, piezometer pore water pressure measurement, piezocon test, dealer torometer test and rowe cell consolidation test are performed as a method for evaluating the soft ground and calculating the engineering properties. The use of the bender element for the soft ground is installed in the triaxial compression cell and used as an actuator and a transducer to measure the stiffness of the soil specimen.

The present invention has been made to solve the problems of the prior art as described above, the technical problem of the present invention is to develop an optimal sensor for continuous consolidation and stiffness evaluation using the vendor element in the soft ground of the field for the soft ground The present invention provides a soft ground measuring device using a vendor element that can measure a good shear wave signal when measuring the stiffness.

  The present invention for solving the above technical problem,

A pile member formed to a predetermined length and mounted to the front end of the mandrel or the drilling machine and penetrated perpendicularly to the soft ground; A pair of horizontal members having one end hinged to allow a predetermined movement in a state in which the one side of the pile member is horizontally disposed with respect to the pile member; And it is provided on the corresponding surface of the horizontal member, respectively, and provides a soft ground measuring apparatus using a bender element, characterized in that it comprises a foot, the oscillation member for oscillating and receiving in the longitudinal direction.

In addition, the horizontal member is characterized in that formed in a rectangular plate shape.

In addition, the horizontal member is formed in a rectangular plate shape having a short length, characterized in that each of the one or more wings protruding to be orthogonal to the longitudinal direction of the horizontal member on both horizontal sides of the horizontal member.

In addition, the horizontal member is characterized in that formed in a zigzag shape.

In addition, the surface corresponding to each other of the horizontal member is characterized in that the one or more resonance pins for distributing the vibration by generating a resonance.

In addition, the oscillation member and the oscillation member is characterized in that consisting of a bender element.

Hereinafter, the soft ground measuring apparatus using the vendor element according to each preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a soft ground measuring apparatus using a bender element according to a first preferred embodiment of the present invention, Figure 2 is a front view of the soft ground measuring apparatus using a bender element shown in FIG. 3A and 3B are cross-sectional views illustrating the oscillation member and the oscillation member shown in FIG. 1.

1 and 2, the soft ground measuring apparatus using the bender element according to the first embodiment of the present invention, a pile member 10, a pair of horizontal members (20, 22), oscillation member 30 and the water receiving member 32.

Pile member 10 is formed in a rod shape having a predetermined length. The pile member 10 is a standard penetration test rod provided at the end of the mandrel (not shown), or the drilling machine (not shown) of the equipment for injecting the vertical drainage material, that is, PBD (Plastic board drain) equipment It is mounted and penetrated perpendicularly to the soft ground by these.

The pair of horizontal members 20 and 22 are hinged 11 at one end in a state in which the pair of horizontal members 20 and 22 are spaced apart from each other so as to be arranged horizontally with respect to the pile member 10 on one side of the pile member 10. Are combined. At this time, each of the horizontal members 20 and 22 is coupled to the pile member 10 by a hinge 11, which is provided with a clearance to allow a predetermined movement using the hinge 11. This is hinged between the pile member 10 and each horizontal member (20, 22) by coupling the horizontal member (20, 22) by the hinge (11) to allow some movement to the pile member (10) Since the gap created by the gap due to the coupling serves to reduce the shear wave entering the pile member 10, it is possible to better measure the shear wave signal.

Each horizontal member 20, 22 in this embodiment is formed in a rectangular plate shape. That is, when the horizontal members 20 and 22 penetrate into the soft ground, the contact with the surrounding soil is improved through the wide contact surfaces of the horizontal members 20 and 22, so that the vibration generated by the oscillation member 30 is increased to the surrounding soil. It is propagated and it can be received by the receiving member 32 to measure a better shear wave signal.

One or more resonant pins 24 having a cantilever shape are provided on surfaces of the horizontal members 20 and 22 that correspond to each other. The resonator pin 24 is formed of a substantially rectangular thin plate, and typically, when the best shear wave signal is measured at about 1000 mW in the soft ground, the thickness (t) = 0.25 mm, It is formed to have a length L of 14 mm and a width b of 5 mm. These resonance pins 24 are each horizontal with the foot, the vibration member 30, 32 is provided to reduce the energy generated by the oscillation member 30 to reach the vibration member 32 riding the pile member 10 It acts as a damper to disperse the vibration so that resonance occurs in the members 20 and 22.

As shown in FIG. 3A, the oscillation member 30 is provided in the horizontal member 20 disposed below one side of the pile member 10. The oscillation member 30 generates vibration in the longitudinal direction by the electrical signal.

As shown in FIG. 3B, the dust collecting member 32 is provided to correspond to the oscillating member 30 in the horizontal member 22 disposed above the one side of the pile member 10. The oscillation member 32 converts the oscillation oscillated from the oscillation member 30 into a voltage to receive it.

The oscillation member 30 and the oscillation member 32 are made of a bender element formed in a state in which the metal plate 38 is bonded between the two ceramics 34 and 36.

Such a bender element causes curvature deformation as the opposite ceramic 36 contracts while one ceramic 34 is stretched when a voltage is applied. That is, when a voltage is applied, the bender element vibrates in the form of a cantilever deformation, and thus may act as the oscillation member 30.

On the contrary, when the bending element is generated from the vent element from the outside, compression and extension strain occur in each of the ceramics 34 and 36, respectively, and electric charges are generated inside the bender element. That is, the vibration can be converted into a voltage, and thus may serve as the vibration member 32.

With this principle, it becomes possible to simply generate vibrations, receive vibrations, and measure them using a vendor element.

Since the said bender element does not have a predetermined standard cross section or manufacturing method, the shape, cross section, and manufacturing method are various. Sections should be constructed to best respond to each test condition or medium to be tested. The bender element has two methods, series and parallel, depending on the bonding method or the terminal connection method of the ceramics 34 and 36 and the metal plate 38.

In this embodiment, the oscillation member 30 has two (-) wires and one (+) connected to a voltage amplifier (not shown) electrically connected to a signal generator (not shown) provided on the soft ground. The wires are formed of parallel connection bender elements formed by connecting two (-) wires to the outside of the ceramic 34 and the other (+) wire to the metal plate 38. The parallel connection bender element is used as the oscillation member 30 because more displacement occurs in the parallel connection than when the same voltage is applied.

On the other hand, the oscillation member 32 is formed of a series connection bender element formed by connecting a (-) wire to the outside of one ceramic 34 and a (+) wire to the opposite ceramic 36. Since the series connection bender element generates a high voltage at a small displacement due to the piezoelectric characteristics, it is used as the vibration receiving member 32.

The resonant frequency of the bender element forming the oscillation member 30 and the oscillation member 32 depends on the size, thickness and length of the bender element as well as the binding force, stress state, density and stiffness applied to the sample. You can also adjust the variables to create the best vendor element for your purpose.

Referring to the operation of the soft ground measuring apparatus using the bender element according to the first embodiment of the present invention configured as described above are as follows.

In the case of measuring the stiffness of the soft ground by applying the soft ground measuring apparatus using the bender element according to the present invention, as shown in FIG. 4, the measuring device is electrically connected to the signal generator, voltage amplifier, and oscilloscope provided on the soft ground. It is fixedly attached to the tip of the mandrel or drilling machine in the connected state.

When the measuring device is mounted on the tip of the mandrel or drilling machine as described above, the measuring device is used to inject the measuring device to the corresponding target depth.

Subsequently, when the measuring device is introduced to the corresponding measuring point, the horizontal member disposed below the pile member 10 by amplifying the electrical signal (about 10V) generated by the signal generator up to 200 times (about 200V) with the voltage amplifier. Vibration is generated in the oscillation member 30 provided at 20. Then, the oscillation member 30 causes one ceramic 34 of the bender element to expand and at the same time the opposite ceramic 36 contracts to cause deformation of the curved shape, thereby vibrating in the form of a cantilever deformation.

The wave caused by the vibration generated by the oscillation member 30 is sensed by the oscillation member 32 provided in the horizontal member 22 disposed above the pile member 10. That is, the oscillation member 30 vibrates because the oscillation member 30 and the oscillation member 32 face each other by horizontal members 20 and 22 arranged horizontally on one side of the pile member 10, respectively, horizontally. Wave is moved in the longitudinal direction to be sensed by the vibration member 32, the vibration member 32 that senses the vibration caused by the vibration is that each ceramic (34, 36) is compressed when the bending deformation occurs in the bender element from the outside And extension deformation occurs to cause charge inside the bender element, thereby converting the vibration into a voltage.

At this time, the horizontal members 20 and 22, each of which the oscillation member 30 and the oscillation member 32 are provided, are formed in a rectangular plate shape so as to have a wide contact surface. Vibration generated in the direction is propagated to the surrounding soil a lot, thereby improving the vibration detection rate by the vibration member 32 can measure a very good shear wave signal.

In addition, each horizontal member (20, 22) is coupled to the pile member 10 through the restrained hinge 11, which is spaced to allow a slight movement with respect to the pile member 10, to the oscillation member (30) In the case of generating the vibration and receiving the vibration member 32, the gap formed by the gap between the pile member 10 and the horizontal members 20 and 22 by the hinge 11 is carried on the pile member 10. By reducing the incoming shear waves, better measurement of shear wave signals is possible.

In addition, in order to reduce the energy generated from the oscillation member 30 to the oscillation member 32 riding the pile member 10, the horizontal members 20 and 22 provided with the foot and the oscillation members 30 and 32. It is possible to measure the shear wave of good quality by dispersing the vibration by providing the resonant pin 24 of the cantilever type so that the resonance occurs in the).

Subsequently, the electrical signal changed into the voltage by the oscillation member 32 is recorded by the oscilloscope and recorded in the recording device, and the data collected by the recording device is analyzed by computer and the strength of the soft ground according to the shear wave velocity by depth is analyzed. Will be measured.

On the other hand, Figure 5 is a perspective view of a soft ground measuring apparatus using a bender element according to a second embodiment of the present invention.

As shown in FIG. 5, the soft ground measuring apparatus using the bender element according to the second exemplary embodiment of the present invention includes a pile member 10, a pair of horizontal members 20 and 22, and an oscillation member 30. ) And a water receiving member 32.

However, the soft ground measuring apparatus according to the second embodiment of the present invention has the following differences in the structure of the soft ground measuring apparatus using the bender element according to the first embodiment.

That is, each horizontal member 20, 22 in the present embodiment is formed in a rectangular plate shape having a short length, and protrudes to be perpendicular to the longitudinal direction of the horizontal member on both horizontal sides of the horizontal member (20, 22) One or more wings 26 are each provided. At this time, the wing 26 is formed in a rectangular plate shape having a thin thickness similar to the horizontal members (20, 22).

Accordingly, the horizontal members 20 and 22 are shortened in length and are provided such that the wings 26 are orthogonal to both horizontal sides of the horizontal members 20 and 22, thereby reducing the size while increasing the contact area with the soil. .

The structure other than the structure of the soft ground measuring apparatus according to the second preferred embodiment of the present invention configured as described above is the same as the soft ground measuring apparatus according to the first preferred embodiment of the present invention.

In the soft ground measuring apparatus using the bender element according to the second preferred embodiment of the present invention configured as described above, the length of the horizontal members 20 and 22 is short and the wings are formed on both sides of the shortened horizontal members 20 and 22. It is provided with (26) to increase the contact area with the soil can be miniaturized, so that it can be easily introduced into the casing of the drilling machine.

On the other hand, Figure 6 is a perspective view of a soft ground measuring apparatus according to a third embodiment of the present invention.

As illustrated in FIG. 6, the soft ground measuring apparatus using the bender element according to the second exemplary embodiment of the present invention includes a pile member 10, a pair of horizontal members 20 and 22, and an oscillation member 30. And a water receiving member 32.

However, the soft ground measuring apparatus according to the third embodiment of the present invention has the following differences in the structure of the soft ground measuring apparatus using the bender element according to the first embodiment.

That is, each of the horizontal members 20 and 22 in the present embodiment is formed in a zigzag shape in which a metal plate having a predetermined length is multiplely bent. In this case, the horizontal members 20 and 22 may be formed in a zigzag shape such as a lightning type, a “Z” shape, an “S” shape, and the like so that the length thereof is shortened and the contact area with the soil is increased. It is shown that it is formed in an S 'shape.

The structure other than the structure of the soft ground measuring apparatus according to the third preferred embodiment of the present invention configured as described above is the same as the soft ground measuring apparatus according to the first preferred embodiment of the present invention.

The soft ground measuring apparatus using the bender element according to the third embodiment of the present invention configured as described above is disposed horizontally on one side of the pile member 10 horizontally as in the second embodiment of FIG. 5. The horizontal members 20 and 22 have a short length and are formed in a zigzag shape so as to increase the contact area with the soil so that the horizontal members 20 and 22 can be easily miniaturized to easily penetrate into the casing of the drilling machine.

As described above, the soft ground measuring apparatus using the bender element according to the present invention is a rectangular so as to be arranged horizontally with respect to the pile member on the upper and lower sides of the pile member mounted perpendicular to the tip of the mandrel or drilling machine. The hinges are coupled to each end of the horizontal member formed in the shape of a plate, and the foot and the oscillation members are provided on the surfaces corresponding to each other of the horizontal members, so that the measuring device is inserted into the soft ground to measure the shear wave signals for each depth. Through contact with the soil through the vibration is generated from the oscillation member is propagated to the surrounding soil a lot, so that the reception rate is improved by the vibration member is provided with an effect that can measure a good shear wave signal.

In addition, the vibration generated from the oscillation member through the pile member to reach the oscillation member through the gap formed by the gap between the pile member and each horizontal member due to the gap between the horizontal member or the resonance pins provided on the corresponding surfaces of each horizontal member. Minimizing vibration also has the effect of enabling better measurement of shear wave signals.

The present invention has been described above by the embodiments, but the present invention is not limited to the above-described embodiments, and those skilled in the art without departing from the gist of the present invention claimed in the claims. Anyone can make a variety of variations.

Claims (6)

A pile member formed to a predetermined length and mounted to the front end of the mandrel or the drilling machine and penetrated perpendicularly to the soft ground; A pair of horizontal members having one end hinged to allow a predetermined movement in a state in which the one side of the pile member is horizontally disposed with respect to the pile member; And Apparatus for measuring the soft ground using a bender element, characterized in that each provided on the corresponding surface of the horizontal member comprises a foot, the oscillation member for oscillating and receiving in the longitudinal direction. The apparatus of claim 1, wherein the horizontal member is formed in a rectangular plate shape having a predetermined length. 2. The bender of claim 1, wherein the horizontal member is formed in a rectangular plate shape having a short length, and one or more wings protruding to be orthogonal to the longitudinal direction of the horizontal member are formed on both horizontal sides of the horizontal member. Soft ground measurement device using the element.  The apparatus of claim 1, wherein the horizontal member is formed in a zigzag shape. The soft ground measuring apparatus according to any one of claims 1 to 4, wherein one or more resonance pins are further provided on surfaces corresponding to each other of the horizontal members to generate resonance to disperse the vibration. . The apparatus of claim 5, wherein the oscillation member and the oscillation member are made of a bender element.

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