JP2007057472A - In situ testing device for investigating anisotropy of foundation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in situ testing device that directly measures to investigate anisotropy of a foundation which has different rigidity in a vertical and a horizontal direction. <P>SOLUTION: The device includes an outer tube that is inserted in a borehole which is cut into a foundation to be investigated, an S-wave generation mechanism in which an inner tube is inserted into the outer tube to combine with the outer tube, an S-wave sensor at an observation point, and an observation device. A plurality of window apertures are formed on the external wall of the outer tube and an S-wave propagation block is installed movably in the inside and the outside directions of each window aperture. A projection type block is mounted in the inner tube. The outer and inner tubes are inserted into the borehole until a predetermined measuring depth, and the S-wave propagation block is pushed out to the outside of the window aperture by operating the inner tube and then is pressure stuck the wall surface of the borehole. Then, an S-wave is generated through the inner tube and an S-wave speed is measured by the S-wave sensor at the observation point and the observation device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of an in-situ test apparatus that directly measures and investigates the anisotropy of ground having different rigidity in the vertical direction and the horizontal direction.

It is known that the ground with an older age has a history of uplift and subsidence, so that the strength and stiffness (Young's modulus) may differ between the vertical and horizontal directions of the ground.
Generally speaking, “anisotropy” includes “strength” that is exhibited when the strain level of the ground is considerably large and “stiffness” at a very small strain level.
In the present invention, it is intended that the rigidity in the vertical direction is different from that in the horizontal direction, but here it is simply defined as “anisotropic”. Among them, the strength is called “strength anisotropy”.
As a conventional technique for grasping the strength anisotropy of the ground, for example, a laboratory test is known. In this test, it is possible to investigate that the strength anisotropy is grasped from the comparison of the respective results by performing a strength test using the undisturbed sample collected from the original position and using the vertical direction and the horizontal direction as axes. On the other hand, the stiffness anisotropy is simply called “anisotropic”, and a shear elastic wave (hereinafter referred to as “S wave”) is used in the same manner as in the strength test. The stiffness can be measured by measuring the velocity or measuring the displacement by applying a very small load in the elastic range of the soil.

However, the above-described measurements by laboratory tests are only to the extent that they have been conducted experimentally. This is because the difference between the vertical direction and the horizontal direction is not taken into the design of the structure in the actual ground, so there was not much need for the method of measuring in situ. Therefore, few methods have been proposed for directly measuring the anisotropy of the ground in situ.
In normal PS logging, S waves are generated on the ground surface or in boreholes to measure the S wave velocity of the ground. It is known that there are two types of S waves, an SV wave whose shear direction is a vertical component and an SH wave whose shear direction is a horizontal component.

The elastic wave velocity measuring method and apparatus disclosed in Patent Document 1 below are used for ground investigation by elastic waves. An elastic wave oscillation source and two receivers that measure the velocity of elastic waves propagating through the ground are housed in a single pipe, penetrated into the ground, and directly sheared in the ground. Thus, a shear elastic wave is generated, and the S wave velocity is obtained from the difference in wave arrival time between the two receivers. It is described that it is not necessary to drill a boring hole in advance, and that elastic wave velocity can be measured accurately and inexpensively continuously in the depth direction.
The ground survey method using the S wave amplitude described in Patent Document 2 hits a rod with a cone attached to the tip into the ground, detects the elastic wave generated at that time by the S wave sensor on the ground surface, It evaluates the mechanical properties of

Japanese Examined Patent Publication No. 7-56513 JP 2003-321828 A

The elastic wave velocity measuring method and apparatus disclosed in Patent Document 1 described above is a compact configuration in which an elastic wave oscillation source and two receivers for measuring elastic wave velocity are housed in one pipe, and The uniqueness of the method of penetrating and using it to pierce the ground is remarkable. However, since the elastic wave oscillation source has a configuration in which a hammer rotated by a motor strikes a rod and directly shears the ground, only one type of SH wave whose shear direction is a horizontal component is generated. Then, two S-waves generated by the clockwise rotation and the counterclockwise rotation are detected by the two receivers, and the elastic wave propagating in the ground from the distance between the two receivers and the wave arrival time difference. Since the speed is obtained, it is considered that there is a great concern about noise contamination due to wave propagation and adverse effects on the accuracy of the measurement value.
In the case of the ground investigation method using the S wave amplitude described in Patent Document 2, an instantaneous elastic wave is detected by an S wave sensor when a rod having a cone attached to the tip is struck into the ground. Therefore, it is a ground survey method with poor reproducibility, and there is a drawback that the factor of analogy judgment is dominant.

  The object of the present invention is that there is little concern about noise contamination, and the necessary test can be reproduced many times under the same conditions. The two types of SV wave and SH wave are used properly, and the elastic wave It is to provide an in-situ testing device that can perform speed measurement with high accuracy, easily understand the presence or absence of ground anisotropy, and contribute to the rational design of structures. .

As a means for solving the above-described problems of the prior art, an in-situ testing apparatus for investigating the anisotropy of the ground according to the invention described in claim 1 is:
An outer tube 3 to be inserted into a bored hole 2 excavated in the ground 1 to be investigated, an S wave generating mechanism 5 formed by inserting and combining the inner tube 4 into the outer tube 3 in a substantially concentric arrangement, and observation It consists of S wave sensors 12 and 13 and an observation device 15.
A plurality of window holes are formed in the outer peripheral wall of the outer tube 3 in the S wave generating mechanism 5, and an S wave propagation block 6 is installed in each window hole so as to be able to enter and exit the window hole.
The inner tube 4 is provided with a protruding block 8 that pushes the S wave propagation block 6 outward of the window hole in an arrangement corresponding to each S wave propagation block 6.
The outer tube 3 and the inner tube 4 of the S wave generating mechanism 5 are inserted into the boring hole 2 in a retracted state in which each S wave propagation block 6 is retracted inward from the outer opening surface of the window hole. At the measurement depth, the inner tube 4 is operated, and each S-wave propagation block 6 is pushed out of the window hole by the protruding block 8 and is crimped to the hole wall surface of the boring hole 2 to generate an S wave through the inner tube 4 and the observation point The S wave velocity is measured by the S wave sensors 12 and 13 and the observation device 15. After the measurement, the inner tube 4 is operated to retract the protruding block 8, and each S wave propagation block 6 is restored and stored in a position inward of the opening surface of the window hole. Then, the outer tube 3 and the inner tube 4 as the S wave generating mechanism 5 are lifted to the ground or moved to different measurement positions.

The invention described in claim 2 is an in-situ test apparatus for investigating the anisotropy of the ground described in claim 1,
The S wave propagation block 6 of the S wave generating mechanism 5 can move in and out by rotating one end common to the horizontal rotation in the horizontal direction in the inner and outer directions of the window hole of the outer tube 3 by the vertical rotation shaft 7. A restoring element such as a spring that is installed and gives a restoring force is installed. On the inner peripheral surface 6 a of the S wave propagation block 6, a slope surface is formed in the same direction in the horizontal rotation so that the extrusion lift becomes higher with the position of the rotary shaft 7 as a base point. The protruding block 8 of the inner tube 4 starts horizontal rotation from a retracted position where it does not contact the S wave propagation block 6, and rotates to a position before reaching the end of the inner peripheral surface 6a of the S wave propagation block 6, S The wave propagation block 6 is pushed out to the outside of the window hole and has an effective height for crimping to the hole wall surface of the boring hole 2. When the protruding block 8 is reversely rotated and retracted by the operation of the inner tube 4, each of the S wave propagation blocks 6 is in an original position inside the opening of the window hole due to the restoring force acting on each S wave propagation block 6. It is the structure which is restored and stored in.

The invention described in claim 3 is the in-situ test apparatus for investigating the anisotropy of the ground described in claim 1,
The S-wave propagation block 6 of the S-wave generating mechanism 5 is installed so as to be able to enter and exit from the window hole of the outer tube 3 substantially horizontally in the inner and outer directions, and a restoring element 16 such as a spring that gives restoring force is installed. The inner peripheral surface 6b of the S-wave propagation block 6 is formed on a slope surface that is inclined upward and downward to increase the extrusion lift. The protruding block 8 of the inner tube 4 reaches the end of the inner peripheral surface 6b of the S-wave propagation block 6 when moved upward or downward from an upper or lower retracted position that does not contact the S-wave propagation block 6. The S-wave propagation block 6 is pushed out to the outside of the window hole by moving to the front position, and has an effective height for crimping to the hole wall surface of the boring hole 2. When the protruding block 8 is moved in the opposite direction by the operation of the inner tube 4 and retracted, the restoring force acting on each S wave propagation block 6 causes each S wave propagation block 6 to be inward of the opening surface of the window hole. In this configuration, the original position is restored and stored.

The invention described in claim 4 is an in-situ test apparatus for investigating the anisotropy of the ground described in any one of claims 1 to 3,
The S wave generated through the inner tube 4 of the S wave generating mechanism 5 is an SV wave whose vertical direction is applied to the inner tube 4 by hitting the inner tube 4 in a vertical direction, or a horizontal rotation applied to the inner tube 4. The shear direction to be generated is two types of SH waves whose horizontal components are horizontal components. These two types of S waves are observed with the vibration sensors 12 and 13 and the observation device 15 at the two observation points, and the S wave velocity of the SV wave and the SH wave is calculated from the time difference of the same waveform, and the anisotropic of the ground It is characterized by investigating sex.

The in-situ testing apparatus of the present invention can be implemented simply and easily by excavating the borehole 2 in the ground 1 to be investigated and inserting the S wave generating mechanism 5 therein. Moreover, the same test can be repeated (reproduced) as necessary at the same measurement position, and the accuracy and certainty of the test can be improved. That is, by fixing the position of the insertion depth of the S wave generating mechanism 5 (outer tube 3) and rotating the inner tube 4 or moving it up and down, each S wave propagation block 6 is moved to the hole of the bore hole 2. The propagation of the S wave can be ensured by crimping to the wall surface. After that, when the vertical hit 20 is applied to the inner tube 4 of the S wave generation mechanism 5 to generate the SV wave or the horizontal rotation 21 to generate the SH wave, each of the S wave propagation blocks 6 is used. Since it propagates into the ground, the S wave can be observed in real time by the vibration sensors 12 and 13 and the observation device 15 at the two observation points, and the anisotropy of the in-situ ground can be directly and accurately measured. And there is almost no possibility of noise mixing.
Moreover, after the measurement, each S wave propagation block 6 can be stored again in the original position inside the opening surface of the window hole by reversely operating the inner tube 4. The outer tube 3 and the inner tube 4 can be lifted to the ground as they are and recovered. Alternatively, the anisotropy of the in-situ ground can be efficiently investigated over a number of required points at different measurement positions with different measurement depths in the borehole 2.

An outer tube 3 to be inserted into a bored hole 2 excavated in the ground 1 to be investigated, an S wave generating mechanism 5 formed by inserting and combining the inner tube 4 into the outer tube 3 in a substantially concentric arrangement, and observation A point S wave sensor 12, 13 and an observation device 15 are used.
A plurality of window holes are formed in the outer peripheral wall of the outer tube 3 in the S wave generating mechanism 5, and an S wave propagation block 6 is installed in each window hole so as to enter and exit the window hole.
The inner tube 4 is provided with a protruding block 8 that pushes the S wave propagation block 6 outward of the window hole in an arrangement corresponding to each S wave propagation block 6.
The S wave generating mechanism 5 (the outer tube 3 and the inner tube 4) is inserted into the boring hole 2 in a retracted state in which each S wave propagation block 6 is retracted inward from the opening surface of the window hole of the outer tube 3. Then, the inner tube 4 is operated at a predetermined measurement depth, and the S-wave propagation blocks 6 are pushed out of the window holes by the protruding blocks 8 and are pressed against the hole wall surfaces of the boring holes 2. Then, an S wave is generated through the inner tube 4 and the S wave velocity is measured by the S wave sensors 12 and 13 and the observation device 15 at the observation point. After the measurement, the inner tube 4 is operated to retract the projecting block 8, and each S wave propagation block 6 is restored and stored in a position inward of the opening surface of the window hole. 3 and the inner tube 4) are lifted to the ground or moved to different measuring positions.

In the following, the present invention will be described with reference to illustrated embodiments.
In the embodiment shown in FIG. 1 to FIG. 3, the S wave generating mechanism 5 of the in-situ test apparatus rotates the inner tube 4 horizontally to push out each S wave propagation block 6 to the outside of the window hole. A case is shown in which the anisotropy of the ground is measured and investigated by crimping to the hole wall surface of the hole 2.
This S wave generating mechanism 5 is combined with an outer tube 3 inserted into a bored hole 2 excavated in the investigation ground 1 and an inner tube 4 inserted into the outer tube 3 in a substantially concentric arrangement. It is configured. As an example, the boring hole 2 is excavated to a depth of several meters underground by a core boring method. The diameter of the hole is about 90 mm, which is slightly larger than the outer diameter (usually about 70 mm) of the outer tube 3 of the S wave generating mechanism 5 so as not to interfere with the insertion of the S wave generating mechanism 5 (the outer tube 3). Drilled with a hole diameter.

As an example, the same number and arrangement of window holes equal to the arrangement of the S wave propagation blocks 6 shown in FIGS. 1A and 1B are formed on the outer peripheral wall (tube wall) of the outer tube 3 of the S wave generating mechanism 5. The S wave propagation blocks 6 are installed in such a manner that they can enter and exit the window hole at a rate of one each.
In the case of the embodiment shown in FIGS. 1 to 3, each S wave propagation block 6 has one end common to the rotation in the horizontal direction at the inside and outside of the window hole of the outer tube 3 by the vertical rotation shaft 7. It is installed so that it can be moved in and out of the horizontal direction. In addition, a restoring element such as a torsion coil spring that applies restoring force to the original retracted position to the S-wave propagation block 6 or a leaf spring that functions as a spring back is wound around the rotary shaft 7 or the S-wave propagation block 6 It is installed in a configuration that directly acts on this (FIGS. 1A to 3A).

  The inner peripheral surface 6a of the S wave propagation block 6 has a form in which the extrusion lift gradually increases in one direction common to horizontal rotation around the rotation shaft 7 with the position of the rotation shaft 7 as a base point (or origin). The extrusion gradient surface is formed in an arc shape. Moreover, the lift gradient of the extrusion gradient surface is such that the projection block 8 of the inner tube 4 to be described later starts rotating from a retracted position where it does not contact the S wave propagation block 6 and the inner circumferential surface 6a of the S wave propagation block 6 The S-wave propagation block 6 is pushed out to the outside of the window hole by the rotation to the position just before reaching the end (see FIG. 2A), and is crimped to the hole wall surface of the boring hole 2 in a state necessary and sufficient for the propagation of the S-wave. Designed and configured.

  On the other hand, in the inner tube 4, the protruding block 8 that pushes out the propagation block 6 to the outside of the window hole is arranged in an arrangement corresponding to each propagation block 6, that is, as shown in FIGS. 1A to 3A. When 4 rotates in one horizontal direction, it contacts the correspondingly arranged propagation block 6 and rotates the S-wave propagation block 6 in accordance with the extrusion lift of the extrusion gradient surface formed on the inner peripheral surface 6a of each propagation block 6. It is installed in such a configuration that it is rotated around the shaft 7 and pushed out of the window hole.

Hereinafter, a method of using the S wave generating mechanism 5 configured as described above with the outer tube 3 and the inner tube 4 as an in-situ testing apparatus for investigating the anisotropy of the ground will be described with reference to FIGS. 5 and 6. explain.
First, two observation holes 10 and 11 are excavated in the investigation ground 1 at a position spaced apart from the boring hole 2 and the boring hole 2. In the two observation holes 10 and 11, vibration sensors 12 and 13 for measuring the S wave velocity are respectively inserted and installed to a predetermined depth. Each of the observation holes 15 and 11 has a ground observation device 15 (such as a personal computer) and a lead wire 18. Connect to make preparations.

On the other hand, the S wave generating mechanism 5 is inserted and installed in the boring hole 2.
That is, each propagation block 6 of the outer tube 3 is inserted into the boring hole 2 in a state of being retracted inward from the opening surface of the window hole (see FIG. 1A). When the S wave generating mechanism 5 reaches a predetermined measurement depth in the borehole 2, first, the outer tube 3 is positioned and fixed by, for example, a dredging facility with a chucking mechanism not shown on the ground. Next, in the case of FIG. 2A, the inner tube 4 is rotated in the horizontal counterclockwise direction, so that each propagation block 6 is pushed out of the window hole by the protruding block 8 of the inner tube 4. Then, crimping is performed on the hole wall surface of the boring hole 2 so that the S wave can propagate.

When the above preparation is completed, an S wave is generated through the inner tube 4 to measure the S wave velocity.
As a method for generating an S wave through the inner tube 4, first, in FIG. 5, a vertical hit 20 is applied to the inner tube 4 protruding to the ground to generate an SV wave whose shear direction is a vertical component. Propagation is made from the inner tube 4 to the ground through the path of the protruding block 8 and the propagation block 6. Alternatively, as shown in FIG. 6, a horizontal rotation 21 is applied to the inner tube 4 to generate an SH wave whose shear direction is a horizontal component, and this is also routed from the inner tube 4 to the protruding block 8 and the propagation block 6. To propagate to the ground.
The two types of S waves (SV wave and SH wave) are received by the vibration sensors 12 and 13 at the two observation points described above, recorded and stored by the observation device 15 on the ground, and having the same waveform. The process of calculating the S wave velocity of the SV wave and the SH wave from the time difference is performed to investigate the anisotropy of the ground.

After the measurement at the measurement position is completed as described above, first, the inner tube 4 of the S wave generating mechanism 5 is operated in the direction opposite to the initial operation, that is, as shown in FIG. The propagating block 6 is released from compression by the projecting block 8 and is restored to the original position inside the opening surface of the window hole by the action of each restoring element and stored (see FIGS. 3A and 3B). reference).
Thereafter, the S wave generating mechanism 5 (the outer tube 3 and the inner tube 4) is pulled up to the ground and recovered. Alternatively, it can be re-installed at a measurement position at a different depth within the same borehole 2 or inserted into a different borehole 2 for the purpose of further ground anisotropy investigation.

  Since it is used as described above, the material of the outer tube 3 and the inner tube 4 of the S wave generating mechanism 5 is made of a metal such as steel that is preferable for the propagation of S waves, more specifically, stainless steel that is resistant to rust. The This point is common to the second embodiment described below.

Next, in the embodiment shown in FIGS. 4A to C, each propagation block 6 of the outer tube 3 is pushed out of the window hole by boring the inner tube 4 of the S wave generating mechanism 5 in the vertical direction. A case is shown in which the anisotropy of the ground is measured and investigated by being crimped to the hole wall surface of the hole 2.
The S wave generating mechanism 5 of the present embodiment is configured such that each propagation block 6 of the outer tube 3 slides in and out of the window hole almost horizontally in the radial direction (inside and outside direction) as detailed in FIG. 4C. ing. On the other hand, the inner tube 4 and its protruding block 8 are configured to move upward and downward.

In the case of the present embodiment, as shown in FIG. 4A, the inner tube 4 has a position above the S wave propagation block 6 as a retracted position that does not contact the S wave propagation block 6. Of course, the position below the S wave propagation block 6 may be a retracted position that does not contact the S wave propagation block 6.
As described above, the S wave propagation block 6 of the outer tube 3 is installed so as to be able to enter and exit from the window hole substantially horizontally, and a restoring element 16 such as a spring for providing restoring force is installed. The restoring element 16 shown in FIG. 4C is a compression coil spring, but is not limited thereto. A disc spring, a leaf spring, or the like can be used as appropriate.

In the case of the illustrated example, the inner peripheral surface 6b of the S wave propagation block 6 is formed in a slope surface that is inclined so as to protrude downward and the extrusion lift becomes higher. However, on the contrary, the inner peripheral surface 6b can be inclined in a downward projecting manner so as to be similarly formed with a configuration in which the inner surface 6b is formed on a sloped surface where the extrusion lift becomes high.
When the protruding block 8 of the inner tube 4 is moved in the downward direction from the upper retracted position where it does not contact the S wave propagation block 6, it first starts to contact the inner peripheral surface 6b of the S wave propagation block 6, The extrusion is started according to the slope of the inner peripheral surface 6b, and the S wave propagation block 6 is required to the outside of the window hole by moving to a position just before reaching the end of the inner peripheral surface 6b (see FIG. 4B). It is designed and constructed so as to have an effective height that can be sufficiently extruded and crimped to the hole wall surface of the boring hole 2 to allow propagation of S waves.

  Therefore, after the ground anisotropy investigation is completed, when the inner tube 4 is operated to move the protruding block 8 upward and retract, the restoring force of the restoring element 16 acting on the S wave propagation block 6 Each S wave propagation block 6 is restored and stored in the original position inside the opening surface of the window hole. Reference numeral 17 in FIG. 4C denotes a positioning stopper that defines the storage position of the S wave propagation block 6.

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the above embodiment. The present invention can be implemented in various ways in design changes, modifications, and applications that are made by those skilled in the art as needed without departing from the spirit and technical idea of the present invention. Insist.

A and B are a horizontal sectional view and a longitudinal sectional view conceptually showing a state in which the S wave generating mechanism of the present invention is inserted into a borehole. A and B are a horizontal sectional view and a longitudinal sectional view conceptually showing a use state in which each propagation block is pressure-bonded to a hole wall surface in a boring hole with an S wave generating mechanism. A and B are a horizontal sectional view and a longitudinal sectional view conceptually showing the configuration in which the S wave generating mechanism is pulled up from the borehole. FIGS. 7A and 7B are a horizontal sectional view and a longitudinal sectional view conceptually showing a state in which an S wave generating mechanism of a different embodiment is inserted into a boring hole. FIGS. C is a horizontal sectional view showing a structure allowing the S wave propagation block to enter and exit. It is sectional drawing which shows notionally the method of investigating the anisotropy of a ground by SV wave using the in-situ test apparatus of this invention. It is sectional drawing which shows notionally the method of investigating the anisotropy of a ground by SH wave using the in-situ test apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Investigation object ground 2 Boring hole 3 Outer tube 4 Inner tube 5 S wave generation mechanism 6 S wave propagation block 20 Vertical hit | damage 21 Horizontal rotation 12, 13 S wave sensor 6a, 6b S wave propagation block 7 Rotating shaft 15 Observation apparatus

Claims (4)

An outer tube inserted into a bored hole excavated in the surveyed ground, an S wave generation mechanism formed by inserting and combining the inner tube into the outer tube in a substantially concentric arrangement, an S wave sensor at the observation point, and Consisting of observation equipment,
A plurality of window holes are formed in the outer peripheral wall of the outer tube in the S wave generating mechanism, and an S wave propagation block is installed in each window hole so as to be able to go in and out of the window hole,
The inner tube is provided with a protruding block that pushes the S wave propagation block outward of the window hole in an arrangement corresponding to each S wave propagation block,
The outer tube and the inner tube of the S wave generating mechanism are inserted into the borehole in a retracted state in which each S wave propagation block is retracted inward from the opening surface of the window hole, and the inner tube is inserted at a predetermined measurement depth. Operate and push out each S wave propagation block to the outside of the window hole by the projection type block and press it to the hole wall surface of the boring hole, and generate S wave through the inner tube, by the S wave sensor and observation device at the observation point S wave velocity measurement is performed, and after the measurement, the inner tube is operated to retract the protruding block, and each S wave propagation block is restored and stored in a position inward of the opening surface of the window hole. An in-situ testing apparatus for investigating the anisotropy of the ground, wherein the outer and inner pipes are pulled up to the ground or moved to different measurement positions.   The S wave propagation block of the S wave generating mechanism is installed so that it can be moved in and out by rotating one end common to horizontal rotation in the horizontal direction to the inside and outside of the window hole of the outer tube by the vertical rotation axis, In addition, a restoring element such as a spring for providing a restoring force is installed, and an inner surface of the S wave propagation block has a gradient surface in which the lift is increased in the same direction in the horizontal rotation with the position of the rotation axis as a base point. The projecting block of the inner tube is formed so that the S-wave propagation block is rotated by a rotation from a retracted position that does not contact the S-wave propagation block to a front position that starts horizontal rotation and reaches the end of the inner peripheral surface of the S-wave propagation block Is pushed out to the outside of the window hole and crimped to the hole wall surface of the boring hole. When the projecting block is rotated backward by the operation of the inner tube, it moves to each S wave propagation block. 2. The ground anisotropy according to claim 1, wherein each of the S wave propagation blocks is restored and stored in an original position inward of the opening surface of the window hole by the restoring force. In-situ testing equipment.   The S-wave propagation block of the S-wave generation mechanism is installed so as to be able to enter and exit from the window hole of the outer tube substantially horizontally, and a restoring element such as a spring for providing restoring force is installed. The inner peripheral surface is formed in a slope surface that inclines upward and downward to increase the extrusion lift, and the protruding block of the inner tube moves upward and downward from the upper or lower retracted position that does not contact the S wave propagation block. When moving in the direction, the structure has an effective height that pushes the S wave propagation block outward of the window hole and crimps it to the hole wall surface of the boring hole by moving to a position before reaching the end of the inner peripheral surface of the S wave propagation block When the projecting block is moved in the reverse direction and retracted by the operation of the inner tube, each S wave propagation block is moved inward from the opening surface of the window hole by the restoring force acting on each S wave propagation block. Configuration restored to location and stored Characterized in that there, in situ testing apparatus for investigating the anisotropy of the ground according to claim 1.   The S wave generated through the inner tube of the S wave generation mechanism is an SV wave whose vertical direction is generated by applying a vertical hit to the inner tube, or shear generated by applying a horizontal rotation to the inner tube. There are two types of SH waves whose directions are horizontal components, and these two types of S waves are observed with two vibration sensors and observation devices at the observation point. From the time difference between the same waveforms, the SV wave and the SH wave The in-situ testing apparatus for investigating the anisotropy of the ground according to any one of claims 1 to 3, wherein the anisotropy of the ground is investigated by calculating a speed.

Images