JP6909025B2 - Measuring device and evaluation test method for ground improvement - Google Patents

Description

The present invention relates to a measuring device and an evaluation test method used for measuring the strength of a ground improvement body for quality evaluation of the ground improvement body.

The following method is known as a method of evaluation test of a ground improvement body constructed in the ground to improve soft ground.
(1) Method 1
A method in which a sample is collected in the form of a slurry in which earth and sand and a solidifying material are mixed, and the material packed in a mold is cured indoors to be solidified, and a strength test is performed at a predetermined age.
(2) Method 2 (Patent Document 1)
A method in which a test piece is collected by boring according to a predetermined age from an improved body solidified in the in-situ position, and a strength test is performed.
(3) Method 3
A method in which a boring hole is prepared in the in-situ position and a loading test is performed inside the hole.

The above method 1 is suitable in terms of workability in that a test piece (test piece) can be collected by a simple operation during the ground improvement work.
Further, in the methods 2 and 3, it is preferable that the ground improvement body actually formed can be cut out or the measurement can be performed at the in-situ position.

Japanese Unexamined Patent Publication No. 2013-194426

However, each of the above-mentioned conventional methods has the following problems.
(1) Problems caused by handling the test piece taken out before solidification Method 1 does not take into account the effects of vehicle transportation, pipe pumping, and ground improvement body formation work performed after the test piece is collected, so the curing temperature and listing The reproducibility of the actual solidification process such as pressure is not perfect, and there may be a discrepancy with the strength achieved at the in-situ of the ground improvement body.
(2) Problems caused by boring work In methods 2 and 3, the compressive strength is too small due to the labor and cost involved in creating the test piece by boring and the damage to the test piece and drilled holes during the boring work. Concerns arise.
(3) Problems related to work efficiency The conventional method 3 requires a special loading device / engineer and is inferior in efficiency.

As described above, there has been a fact that the conventional method cannot achieve both the reliability of measurement data and the efficiency of test work at a high level.
Therefore, an object of the present invention is to provide a means capable of achieving both reliability of measurement data and efficiency of test work.

The first invention of the present application, which has been made to solve the above problems, is a measuring device having a peripheral wall of a long hole formed in a ground improvement body as a measurement point, and has a main body portion capable of penetrating the long hole and the said. A wheel provided in the main body, a drive mechanism for driving the wheel to allow self-propelled operation, a self-supporting mechanism for pressing the wheel against the peripheral wall with a predetermined force, and a self-supporting mechanism provided in the main body for measurement. It is characterized by having at least a test means capable of performing a penetration test at a site.
The second invention of the present application is a test method for evaluating the strength of a ground improvement body for quality evaluation of the ground improvement body, wherein (A) a step of forming an elongated hole in the ground improvement body, (B) the above. An evaluation test method for a ground improvement body, which comprises at least a step of intruding the measuring device according to the first invention into an elongated hole and performing a penetration test using the peripheral wall of the elongated hole as a measurement point. offer.
Further, in the third invention of the present application, in the second invention, the step (A) is (A1) a step of arranging an insertion member in the ground improvement body before solidification, (A2) the ground improvement body. It is characterized by including at least a step of pulling out the insertion member after solidification and making the pulled out space into the elongated hole.
Further, in the fourth invention of the present application, in the third invention, the insertion member used in the step (A1) is formed into a tubular shape, and when the insertion member is pulled out in the step (A2), the inside of the insertion member is inserted. It is characterized in that the existing solidified ground improvement body is separately collected as a test body.
Also, a fifth aspect of the present invention, in any one of the invention of the second through fourth aspects, the measuring device, the measurement data obtained by the measurement points, and can be transmitted in configuration to the outside of the information processing apparatus It is characterized by being.

According to the present invention, the effects described below are obtained.
(1) The reliability of the measurement data is high.
Since the ground improvement body actually formed is targeted for measurement, the reliability of the measurement data obtained from the measurement data is high.
Further, in normal boring work, the steel pipe rotates while in contact with the hole wall, and the test piece and the drilled hole are easily damaged. However, in the present invention, the boring work is unnecessary, so that such damage occurs. Therefore, the accuracy of the evaluation result is excellent.
(2) It is possible to automate / semi-automate the measurement work.
If the measuring device is configured to perform the long hole running work and the measuring work automatically or semi-automatically, one technician can perform the quality confirmation work in parallel using multiple measuring devices, which saves labor.・ Contribute to labor saving.
(3) Quality confirmation can be performed quickly on the spot.
Since the conversion from the penetration resistance value obtained by the penetration test to the uniaxial compressive strength is performed by a simple calculation, quality confirmation can be performed quickly on the spot.

The schematic diagram which shows the whole structure of the measuring apparatus which concerns on Example 1. FIG. The schematic diagram which shows the procedure of the evaluation test method of the ground improvement body which concerns on Example 2. The schematic diagram which shows the procedure of the evaluation test method of the ground improvement body which concerns on Example 3. FIG. The schematic diagram which shows the modification of the measuring apparatus which concerns on Example 4. FIG.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.
For convenience of explanation, first, the outline of the measuring device used in the evaluation test method of the ground improvement body according to the present invention will be described.

<1> Overall configuration FIG. 1 is a schematic view showing the overall configuration of the measuring device according to the present embodiment.
The measuring device A according to the present invention includes at least a main body 10 and a test means 20, and can include a communication means 30 as needed.
The main body 10 is provided with four wheels 11 in contact with the long hole Y around the main body portion 10 and can move up and down in the long hole Y. Is moved, a penetration test is performed using the rod 21, and the result of the penetration test is transmitted to a receiver (not shown) provided outside the slot Y using the communication means 30 to receive the result. Save the results in a storage device (not shown) connected to the machine.
The details of each means will be described below.

<2> Main body The main body 10 is a member corresponding to the base of a measuring device, and is a box-shaped device provided with a test means 20, a communication means 30, and the like, and has a size capable of penetrating into an elongated hole Y. ..

<2.1> Moving Mechanism In this embodiment, four wheels 11 are provided around the main body of the measuring device A so as to be in contact with the peripheral wall Y1 of the elongated hole Y.
The wheel 11 can self-propell in the elongated hole Y by a drive mechanism such as a motor provided in the main body 10, and can be stopped at a predetermined depth.

<2.2> Self-supporting mechanism Since the elongated hole Y is formed in the vertical direction in this embodiment, the wheel 11 is suspended on the peripheral wall Y1 side so that the measuring device A does not fall in the elongated hole Y due to gravity (Fig. It is possible to stand on its own by pressing it with a predetermined force with (not shown) and maintaining the state of being stretched in the elongated hole Y.
By rotating the wheel 11 with a drive mechanism such as a motor, the wheel 11 can freely travel in the elongated hole Y.
At the time of the test, a stable measurement result can be obtained by fixing the main body and the hole wall by a means different from that of the wheel 11 to prevent the device from falling and fixing the main body.

<3> Test means The test means 20 is a means for carrying out a penetration test at a measurement point.
Conventional penetration test devices include a method of penetrating with an indoor load test device and a method of penetrating by using a reaction force as human force using a commercially available handy-sized device. These devices are used as the test means 20 according to the present invention. Can be mounted on the main body 10.
The test means 20 according to the present embodiment includes a rod 21 that can be stretched so as to penetrate toward the measurement point Z, and a device that reads, records, or communicates the resistance value due to the penetration of the rod 21 with a load cell. It is possible to measure the penetration resistance and the penetration amount due to the penetration of 21.

<3.1> Correlation between penetration resistance and uniaxial compressive strength It is known that the above-mentioned penetration resistance has a correlation with uniaxial compressive strength, which is a general quality index, and is also a standard as a test method. It is a reliable and reliable method.

<3.2> Handling of measurement data The data measured by the test means 20 is stored for each measurement location, and after all the measurement work is completed and the measuring device A is taken out from the slot Y, all the measurements are performed. The data may be taken out, or the measurement data may be appropriately transmitted to an external information processing device by the communication means 30 described later.

<4> Communication means The communication means 30 is a means for communicating with an external information processing device.
The communication content by the communication means 30 includes communication for remotely controlling the measuring device A from the outside, communication for transmitting the measurement data obtained by the test means 20 to an external information processing device, and the like.
The communication means 30 may be appropriately selected from known wired communication and wireless communication.

Next, the evaluation test method according to the second embodiment of the present invention will be described with reference to FIG.

<1> Outline of procedure In the evaluation test method according to the present embodiment, the measuring device A and the insertion member B according to the above-mentioned Example 1 are used, and the insertion member B is formed on the ground improvement body X in the substantially vertical direction. The horizontal penetration test is carried out by the measuring device A with the peripheral wall Y1 of the elongated hole Y in the longitudinal direction as the measuring point Z.
The details of each procedure will be described below.

<2> Insertion of insertion member (Fig. 2 (a))
First, the insertion member B is inserted into the ground improvement body X before solidification formed in the ground.
It is preferable that the head of the insertion member B is exposed to the ground so that it can be taken out after the fact.

<2.1> Outline of the insertion member As the insertion member B, a long rod member can be used.
The cross-sectional shape of the insertion member B is not particularly limited, such as a rectangle, a circle, or another polygon.
In this embodiment, a solid bar having a circular cross-sectional shape is used for the insertion member B.

<2.2> Application of lubricant to the outer circumference It is preferable to apply a lubricant to the outer circumference of the insertion member B.
This lubricant exerts a function of reducing the frictional resistance between the ground improvement body X before solidification and the insertion member B.
Examples of the lubricant include lubricating oil, grease, silicone oil, concrete mold release agent, softener and the like.

<3> Removal of the insertion member (Fig. 2 (b))
After the predetermined curing period for the ground improvement body X has elapsed, the insertion member B is pulled up from the solidified ground improvement body X and taken out.
The portion from which the insertion member B is extracted becomes an elongated hole Y and becomes an open space provided with an opening.

<4> Start of survey (Fig. 2 (c) (d))
The measuring device A according to the present invention is inserted through the opening of the long hole Y, and the measuring device A is driven to the deepest measurement point Z1 in the long hole Y (FIG. 2 (c)).
At this time, since the measuring device A moves in a posture of stretching in the elongated hole Y, it does not fall into the elongated hole Y.
In this embodiment, the measuring device A is first moved to the deepest part of the elongated hole Y, and the measuring points Z2 ... Zn set at appropriate intervals above the deepest part are sequentially measured and measured. While repeating the movement of A, the measured values of the horizontal penetration test at each measurement point are recorded (Fig. 2 (d)).

<5> Summary As described above, according to the evaluation test method according to the present invention, by using a measuring device capable of traveling in an elongated hole, the measurement work at the in-situ position can be performed while changing the measurement location. The efficiency of test work can be improved.
In addition, since the actually formed ground improvement body is targeted for measurement, the inside of the ground improvement body is not damaged by boring, and the reliability of the measurement data is high.
Therefore, it is possible to improve the reliability of the measurement data and improve the efficiency of the test work at the same time.
In recent years, probabilistic evaluation has been introduced in design studies related to the ground, and it is desirable to acquire enough data for the statistical processing of the ground improvement strength. According to the measuring device according to the present invention. Since the measurement data can be efficiently acquired from many measurement points, the above request can be met.

In the present invention, when the insertion member B is formed in a tubular shape and the insertion member B is pulled out from the solidified ground improvement body X, the solidified ground improvement body X existing inside the insertion member B is indoors. It can also be collected as a test body X1 for testing.
The evaluation test method according to the third embodiment of the present invention will be described with reference to FIG.

<1> Configuration of Insertion Member In this embodiment, the insertion member B is configured in a tubular shape so that the ground improvement body X before solidification flows into the insertion member B.
The solidified ground improvement body X that has flowed into the inside is recovered as a test body X1 for laboratory test.

<2> Friction reduction structure Further, it is preferable to provide a structure capable of reducing friction with the ground improvement body X before solidification on the inner peripheral surface of the insertion member B.
This reduces the friction generated between the ground improvement body X before solidification and the insertion member B, so that when the insertion member B is inserted, the internal ground improvement body X is not pushed into the back and a predetermined depth is obtained. This is to keep it in a maintained state.
With this configuration, there is no difference in the density of the ground improvement body X inside and outside the insertion member B, so that the ground improvement body X1 maintained in an appropriate state can be recovered.

The following aspects can be considered for this friction reduction structure.
(Aspect 1) A mode in which a surface coated with a lubricant is provided on the inner peripheral surface of the insertion member B.
(Aspect 2) The area of the inner peripheral surface is reduced as much as possible by providing an opening on the inner peripheral surface of the insertion member B. (Aspect 3) The material on the inner peripheral side of the insertion member B has a low friction coefficient. Aspect made of material.

<3> Insertion member tip closing mechanism Further, the insertion member B has a lid capable of closing the tip of the insertion member B so that the internal ground improvement body X does not fall off when the insertion member B is taken out. The body 40 may be provided.
This is because the friction reducing structure provided on the inner peripheral surface of the insertion member B may leave the ground improvement body inside when the insertion member B is pulled out.
In this embodiment, a lid 40 that is hinged to the tip of the insertion member B and is movable so as to close the tip from the state of being housed in the side wall of the insertion member B is provided.

<4> Summary As described above, according to the evaluation test method according to the present embodiment, in addition to the measurement data at the in-situ position described in the first embodiment, the laboratory test of the test body taken out from the inside of the insertion member is performed. By targeting the measurement data as an evaluation target, a more reliable evaluation test can be carried out.

In the measuring device according to the present invention, the main body may further adopt the following movement modes.
FIG. 4 shows a modified example of the main body.

(1) Suspended type (FIGS. 4 (a) and 4 (b))
This is a method in which a traction device is provided separately from the measuring device A according to the present invention, and the measuring device A is connected to the traction device to suspend it into the elongated hole Y.
In this case, the side surface of the main body 10 may come into contact with the peripheral wall Y1 in the elongated hole Y to position the measuring device A and obtain a reaction force from the peripheral wall Y1 when the penetration test is performed. Must be configured to be possible.
As an example of the positioning structure, as shown in, a method of providing an expandable packer 12 on the side surface of the main body portion (FIG. 4A), or a method of expanding and contracting the side surface of the main body portion 10 in the radial direction of the elongated hole Y. There is a method of providing the leg portion 13 (FIG. 4B).

(2) Telescopic type (Fig. 4 (c))
This is a method of moving in the peripheral wall Y1 by expanding and contracting the main body itself.
As an example of the telescopic type, the main body 10 itself is separated in the traveling direction (main bodies 10a and 10b), and leg portions 13 that can be expanded and contracted in the radial direction of the elongated hole Y are provided on the side surfaces of the main bodies 10a and 10b. The measuring device A is scaled on the peripheral wall Y1 by extending the main body while the legs of one main body 10a stretch between the peripheral walls Y1 and the legs of the other main body are separated. Can be moved like this.

In the inventions according to Examples 1 to 4 described above, the measurement target is the ground improvement body X, but in the present invention, the natural ground may be the evaluation target.
First, when applied to natural ground, an elongated hole Y is formed by boring.
The type of boring may be either core boring or non-core boring.
In the case of soft ground where the elongated hole Y does not stand on its own, a method of measuring while holding the hole wall with muddy water such as bentonite can be considered.
In that case, the measuring device A according to the present invention needs to be waterproof.
In addition, it is preferable to adopt a structure that reduces the buoyancy of the entire device, such as reducing the volume of the main body 10 as much as possible or incorporating a weight in the main body 10 so as not to interfere with work in muddy water. Is.

Further, since the hardness range of the natural ground is wide, the thickness of the rod 21 for measuring the penetration resistance value can be changed, and the penetration test can be performed by a suitable rod 21.
At this time, there is a method in which a plurality of rods 21 are provided in the main body 10 so that a suitable rod 21 can be selected from the rods 21 or the rods 21 can be replaced.

A Measuring device 10 Main body 11 Wheel 12 Packer 13 Leg 20 Test means 21 Rod 30 Communication means B Insert member X Ground improvement body X1 Test body Y Long hole Y1 Peripheral wall Z Measurement point

Claims (5)

It is a measuring device that uses the peripheral wall of a long hole formed in the ground improvement body as the measuring point.
The main body and the main body that can penetrate the elongated hole
Wheels and wheels provided on the main body
A drive mechanism that drives the wheels to enable self-propelling,
A self-supporting mechanism capable of pressing the wheel against the peripheral wall with a predetermined force,
A test means provided on the main body and capable of performing a penetration test at the measurement point.
Characterized by having at least
Measuring device for ground improvement body. This is a test method for evaluating the strength of a ground improvement body for quality evaluation of the ground improvement body.
(A) Ground improvement step of forming a long hole in the body,
(B) A step of inserting the measuring device according to claim 1 into the elongated hole and performing a penetration test using the peripheral wall of the elongated hole as a measurement point.
Characterized by containing at least
Evaluation test method for ground improvement bodies. The step (A)
(A1) The process of arranging the insertion member on the ground improvement body before solidification,
(A2) A step of pulling out the insertion member after solidification of the ground improvement body and using the pulled out space as the elongated hole.
Is characterized by containing at least
The evaluation test method for a ground improvement body according to claim 2. The insertion member used in the step (A1) has a tubular shape.
When the insertion member is pulled out in the step (A2), the solidified ground improvement body existing inside the insertion member is separately collected as a test body.
The evaluation test method for a ground improvement body according to claim 3. The measuring device is characterized in that the measurement data obtained at the measurement point can be transmitted to an external information processing device.
The evaluation test method for a ground improvement body according to any one of claims 2 to 4.

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