JP2018159237A - Measurement device and evaluation testing method for ground improvement body - Google Patents

Abstract

An object of the present invention is to achieve both the reliability of measurement data and the efficiency of test work.
A measuring apparatus A having at least a main body 10 capable of entering a slot of a ground improvement body and a test means 20 capable of performing a penetration test at a measurement location is used. First, the insertion member B is arranged in the ground improvement body X before solidification, the insertion member B is pulled out after the ground improvement body X is solidified, and the measuring device A is caused to travel in the long hole Y formed of the extracted space. The operation for performing the penetration test at a predetermined measurement location is repeated until the operations at all measurement locations are completed.
[Selection] Figure 2

Description

  The present invention relates to a measuring apparatus 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 for evaluating the ground improvement body constructed in the ground in order to improve the soft ground.
(1) Method 1
A method of collecting a sample in a slurry state in which earth and sand and a solidifying material are mixed, curing the material packed in a mold and solidifying it in a room, and performing a strength test at a predetermined age.
(2) Method 2 (Patent Document 1)
A method in which a test specimen is sampled by boring from an improved body solidified in situ according to a predetermined age, and a strength test is performed.
(3) Method 3
A method in which a boring hole is prepared in-situ and a loading test is performed inside.

The method 1 is preferable in terms of workability in that the specimen (specimen) can be collected by a simple work during the ground improvement work.
In the methods 2 and 3, it is preferable that the ground improvement body actually formed can be cut out or measured at the original position.

JP 2013-194426 A

However, each of the conventional methods described above has the following problems.
(1) Problems caused by handling of test specimens taken out before solidification Method 1 does not take into account the effects of vehicle transportation, piping pumping, ground improvement body formation work, etc. performed after sampling of specimens. The reproducibility of the actual solidification process such as pressure is not perfect, and there may be a discrepancy between the strength achieved at the original position of the ground improvement body.
(2) Problems caused by boring work In methods 2 and 3, the compressive strength is too low due to the labor and cost of creating the test specimen by boring, and damage to the test specimen and the hole in the drilling work. This raises some concerns.
(3) Problems related to work efficiency Conventional method 3 requires a special loading device / engineer and is inefficient.

As described above, the conventional method has a situation that the reliability of the measurement data and the efficiency of the test work are not compatible at a high level.
Accordingly, an object of the present invention is to provide means capable of achieving both the reliability of measurement data and the efficiency of test work.

1st invention of this application made to solve the said subject is the measuring device which makes the measurement location the peripheral wall of the long hole formed in the ground improvement body, Comprising: The main-body part which can penetrate | invade into the said long hole, It is provided with a test means which is provided in a main-body part and can perform a penetration test in the said measurement location, It is characterized by the above-mentioned.
The second invention of the present application is a test method for evaluating the strength of the ground improvement body for the quality evaluation of the ground improvement body, wherein (A) a step of forming a slot in the ground improvement body, (B) A ground improvement body evaluation test method, comprising at least a step of penetrating the measuring device according to the first invention into a long hole and performing a penetration test using the peripheral wall of the long hole as a measurement location. provide.
In addition, in the third invention of the present application, in the second invention, the step (A) includes (A1) a step of placing an insertion member in the ground improvement body before solidification, and (A2) of the ground improvement body. It is characterized by comprising at least a step of pulling out the insertion member after solidification and making the extracted space the elongated hole.
Moreover, 4th invention of this application makes the insertion member used in the said process (A1) into a cylindrical shape in the said 3rd invention, When pulling out an insertion member in the said process (A2), it is inside a plugging member. The existing ground improvement body after solidification is separately collected as a test body.
According to a fifth invention of the present application, in any one of the second to fourth inventions, the measuring device is configured to be able to travel in the elongated hole.
According to a sixth invention of the present application, in any one of the second to fifth inventions, the measurement device is configured to transmit measurement data obtained at a measurement location to an external information processing device. It is characterized by being.

According to the present invention, the following effects can be obtained.
(1) The reliability of measurement data is high.
Since the ground improvement body actually formed is a measurement object, the reliability of the measurement data obtained from the measurement data is high.
Also, in normal boring operations, the test specimen and drilled holes are easily damaged by rotating the steel pipe in contact with the hole wall, etc., but in the present invention, since the boring operation is unnecessary, these damages occur. Therefore, the accuracy of the evaluation result is excellent.
(2) Measurement work can be automated / semi-automated.
If the measuring device is configured to automatically or semi-automatically perform the long hole traveling and measuring operations, it is possible for one engineer to perform simultaneous quality check operations using multiple measuring devices, saving labor.・ Contributes 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, the quality can be quickly confirmed on the spot.

1 is a schematic diagram illustrating an overall configuration of a measurement apparatus according to Embodiment 1. FIG. Schematic which shows the procedure of the evaluation test method of the ground improvement body which concerns on Example 2. FIG. Schematic which shows the procedure of the evaluation test method of the ground improvement body which concerns on Example 3. FIG. FIG. 10 is a schematic diagram illustrating a modification of the measurement apparatus according to the fourth embodiment.

Embodiments according to the present invention will be described below with reference to the drawings.
For convenience of explanation, first, an outline of a measuring apparatus used in the ground improvement body evaluation test method according to the present invention will be described.

<1> Overall Configuration FIG. 1 is a schematic diagram illustrating the overall configuration of a measurement apparatus according to the present embodiment.
The measuring apparatus A according to the present invention includes at least a main body 10 and a test unit 20, and may include a communication unit 30 as necessary.
The main body portion 10 includes four wheels 11 in contact with the elongated hole Y around the periphery, and can move up and down in the elongated hole Y. The main body portion 10 can be moved to an arbitrary measurement position of the elongated hole Y with the wheel 11. After the movement, the penetration test is performed using the rod 21, and the result of the penetration test is transmitted to the receiver (not shown) provided outside the long hole Y using the communication means 30. The result is stored in a storage device (not shown) connected to the machine.
Details of each means will be described below.

<2> Main Body The main body 10 is a member that corresponds to the base of the measuring device, and is a box-shaped device that is provided with the test means 20, the communication means 30, and the like and has a size that can penetrate into the long hole Y. .

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

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

<3> Test means The test means 20 is means for carrying out a penetration test at a measurement location.
Conventional penetration testing devices include a method of penetrating with an indoor loading test device, a method of penetrating reaction force as human power using a commercially available handy size device, and these devices are used as 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 and records or communicates a resistance value due to penetration of the rod 21 with a load cell. The penetration resistance and penetration amount due to the penetration of 21 can be measured.

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

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

<4> Communication Unit The communication unit 30 is a unit for communicating with an external information processing apparatus.
The contents of communication by the communication means 30 include communication for remotely operating the measuring apparatus A from the outside, and communication for transmitting measurement data obtained by the test means 20 to an external information processing apparatus.
The communication means 30 may be appropriately selected from known wired communication and wireless communication.

  Next, an evaluation test method according to Example 2 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 substantially vertical direction formed on the ground improvement body X by the insertion member B using the measuring device A and the insertion member B according to the first embodiment. A horizontal penetration test is carried out with the measuring device A, with the peripheral wall Y1 of the long hole Y having the longitudinal direction as the measurement location Z.
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.
If the head of the insertion member B is exposed to the ground, it is preferable in that the subsequent removal becomes easier.

<2.1> Outline of Insertion Member The insertion member B can be a long bar.
The cross-sectional shape of the insertion member B is not particularly limited, such as a rectangle, a circle, and other polygons.
In the present embodiment, a solid bar having a circular cross-sectional shape is used for the insertion member B.

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

<3> Removing the insertion member (FIG. 2B)
After the predetermined curing period for the ground improvement body X has elapsed, the insertion member B is pulled up and taken out from the solidified ground improvement body X.
The part from which the insertion member B is extracted becomes a long hole Y and becomes an open space provided with an opening.

<4> Start of investigation (Fig. 2 (c) (d))
The measuring apparatus A according to the present invention is caused to enter from the opening of the long hole Y, and the measuring apparatus A travels to the deepest measurement location Z1 in the long hole Y (FIG. 2 (c)).
At this time, since the measuring apparatus A moves in a posture of stretching in the long hole Y, it does not fall into the long hole Y.
In this embodiment, first, the measuring device A is moved to the deepest portion of the long hole Y, and the measurement and measuring device are sequentially performed on the measurement points Z2... Zn set with an appropriate interval upward from the deepest portion. While repeating the movement of A, the measurement value of the horizontal penetration test at each measurement point is recorded (FIG. 2 (d)).

<5> Summary Thus, according to the evaluation test method according to the present invention, by using a measuring device capable of traveling in the long hole, by performing the measurement work at the original position while changing the measurement location, Test work can be made more efficient.
Moreover, since the ground improvement body actually formed is used as a measurement object, the inside of the ground improvement body is not damaged by boring, and thus the reliability of the measurement data is high.
Therefore, it is possible to improve both the reliability of measurement data and the efficiency of test work.
In recent years, probabilistic evaluation has been introduced in design studies related to the ground, and it is desirable to acquire data sufficient for statistical processing regarding ground improvement strength. According to the measuring device according to the present invention, Since the measurement data can be efficiently acquired from many measurement locations, the above-mentioned demand can be met.

In the present invention, the insertion member B is formed into a cylindrical shape, and when the insertion member B is pulled out from the ground improvement body X after solidification, the ground improvement body X after solidification existing inside the insertion member B is It can also be recovered as a test specimen X1.
An evaluation test method according to Example 3 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 cylindrical shape, and the ground improvement body X before solidification is configured to flow into the insertion member B.
The ground improvement body X after solidification that has flowed into the interior is collected as a test body X1 for laboratory testing.

<2> Friction reduction structure Moreover, it is preferable to provide the inner peripheral surface of the insertion member B with a structure capable of reducing friction with the ground improvement body X before solidification.
This is to reduce 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 the predetermined depth is increased. This is to maintain the state.
If it is set as the said structure, since a difference does not arise in the density of the ground improvement body X in the inside and outside of the insertion member B, the ground improvement body which maintained the suitable state as the test body X1 is recoverable.

The following modes can be considered for this friction reducing structure.
(Aspect 1) An aspect in which a lubricant application surface is provided on the inner peripheral surface of the insertion member B.
(Aspect 2) A mode in which 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 coefficient of friction. Manufacture with material.

<3> Insertion member distal end closing mechanism Further, the insertion member B has a lid capable of closing the distal end of the insertion member B so that the 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 is provided which is hinged to the tip of the insertion member B and is movable so as to close the tip from the state accommodated in the side wall of the insertion member B.

<4> Summary As described above, according to the evaluation test method according to the present example, in addition to the measurement data at the original position described in the first example, it is based on the laboratory test of the test specimen taken out from the inside of the insertion member. By using measurement data as an evaluation target, a more reliable evaluation test can be performed.

In the measuring apparatus according to the present invention, the main body may further adopt the following movement mode.
FIG. 4 shows a modification of the main body.

(1) Hanging type (Fig. 4 (a) (b))
In this method, a traction device is provided separately from the measurement device A according to the present invention, and the measurement device A is connected to the traction device and suspended in the elongated hole Y.
In this case, the side surface of the main body 10 may contact the peripheral wall Y1 in the long hole Y as necessary to position the measuring device A and obtain a reaction force from the peripheral wall Y1 during the penetration test. Must be configured as possible.
Examples of the positioning structure include a method of providing an inflatable packer 12 on the side surface of the main body (FIG. 4A), and the side surface of the main body 10 can be expanded and contracted in the radial direction of the long hole Y. There is a method (FIG. 4B) for providing a leg portion 13.

(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 a telescopic type, the main body part 10 itself is separated in the traveling direction (main body parts 10a and 10b), and leg parts 13 that can be expanded and contracted in the radial direction of the long hole Y are provided on the side surfaces of the main body parts 10a and 10b. The measuring device A is scaled on the peripheral wall Y1 by stretching the main body portion in a state where the leg portion of the other main body portion is separated while the leg portion of the main body portion 10a is stretched between the peripheral walls Y1. Can be moved.

In the inventions according to the first to fourth embodiments described above, the measurement object is the ground improvement body X, but the present invention may be the natural ground.
First, when applying to natural ground, the long 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 long 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 apparatus A according to the present invention needs to be waterproof.
Also, 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 hinder the work in the muddy water. It is.

In addition, 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 with the suitable rod 21.
At this time, there is a method in which a plurality of rods 21 are provided in the main body 10 and a suitable rod 21 is selected from among them, or the rod 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 Circumferential wall Z Measurement location

Claims (6)

A measuring device that uses a peripheral wall of a long hole formed in the ground improvement body as a measurement location,
A main body that can enter the elongated hole;
A test means provided on the main body and capable of performing a penetration test at the measurement location;
Having at least
Measuring device for ground improvement bodies. A test method for evaluating the strength of a ground improvement body for quality evaluation of the ground improvement body,
(A) forming a long hole in the ground improvement body,
(B) A process of performing a penetration test using the measuring device according to claim 1 in the elongated hole and using the peripheral wall of the elongated hole as a measurement location;
Including at least
Evaluation test method for ground improvement bodies. The step (A)
(A1) A step of placing the insertion member on the ground improvement body before solidification,
(A2) extracting the insertion member after solidifying the ground improvement body, and making the extracted space the elongated hole;
Comprising at least
The ground improvement body evaluation test method according to claim 2. The insertion member used in the step (A1) is cylindrical,
When extracting the insertion member in the step (A2), the ground improvement body after solidification existing in the insertion member is separately collected as a test body,
The ground improvement body evaluation test method according to claim 3. The measuring device is configured to be able to travel in the elongated hole,
The ground test body evaluation test method according to any one of claims 2 to 4. The measurement device is configured to transmit measurement data obtained at a measurement location to an external information processing device,
The ground test body evaluation test method according to any one of claims 2 to 5.

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