JP7557783B2 - Fuel agent performance verification test method and test device - Google Patents

Description

The present invention relates to a method and device for testing injection performance.

By constructing a frozen ground _GF using the ground freezing method, a water-stopping structure can be constructed in the ground, or a retaining wall or a water-stopping wall can be formed (see FIG. 6(a)). However, due to the flow of groundwater W, a water path _PW can be formed in the frozen ground _GF , or the ground cannot be frozen, resulting in incomplete construction of the frozen ground _GF (see FIG. 6(b)). For this reason, the ground freezing method and the chemical injection method can be used together to block the water path _PW (see FIG. 6(c)). Here, FIGS. 6(a) to (c) are cross-sectional views that show a schematic view of a frozen ground _GF .
For example, Patent Document 1 discloses a ground improvement method in which, when excavating a tunnel, a water-stopping area is formed by a chemical injection method in a state surrounding the excavated part of the tunnel, and the part along the excavated part in the water-stopping area is frozen by a ground freezing method. The ground improvement method of Patent Document 1 forms a water-stopping area by chemical injection so as to surround the construction area, so it is necessary to carry out chemical injection over a wide area. Therefore, construction is time-consuming and prevents cost reduction.
On the other hand, in order to block the water path _PW , as shown in Fig. 6(c), there are cases where chemical injection C is performed partially into the frozen ground _GF , but chemical injection C under low temperature conditions may not be effective enough depending on the grouting agent. Therefore, when using the chemical injection method in combination with the ground freezing method, it is necessary to check the performance of the grouting agent in advance, but it is difficult to artificially form a water path _PW in the frozen ground _GF and perform a test of partial chemical injection in situ.

Japanese Patent Application Publication No. 3-13690

The objective of the present invention is to propose a method and testing device for verifying the performance of a grouting agent that can easily verify whether the desired performance can be ensured when the grouting agent is injected into frozen ground.

The injection agent performance confirmation test method of the present invention for solving the above problems includes a specimen installation step of placing a specimen cooled to below freezing in a container, an injection agent injection step of injecting a chemical injection agent so that it comes into contact with the specimen, and a performance confirmation step of confirming the presence or absence of resistance when the contact surface between the specimen and the chemical injection agent is shifted.
In this grout performance confirmation test method, the adhesion between the specimen and the hardened grout by checking the presence or absence of resistance that occurs when the contact surface between the specimen and the grout is shifted is confirmed. In other words, if the resistance is confirmed, it can be judged that the specimen and the hardened body are adhered to each other and the grout is exhibiting the desired performance. Therefore, for example, it can be used as a grout when a grouting method is used in combination with the aim of improving the water-stopping property of frozen ground. On the other hand, if there is no resistance, it is presumed that the grout will not harden under low temperature conditions or that the surface of the specimen will thaw due to the heat generated when the grout hardens. Therefore, it can be judged that the grout is not suitable for frozen ground.

In the grout performance confirmation test method, it is preferable that the columnar specimen is placed in the container in the specimen installation work, the grout injection work fills the gap between the specimen and the container with the liquid grout, and the performance confirmation work lifts the specimen and measures the load when lifting the specimen. According to this grout performance confirmation test method, by confirming that the load when lifting the specimen exceeds the weight of the specimen, the adhesion state between the specimen and the hardened body of the liquid grout can be quantitatively confirmed.
Furthermore, if the system is equipped with an adhesion strength calculation process that calculates the adhesion strength by subtracting the weight of the test specimen from the load and dividing the result by the contact area between the test specimen and the liquid injection agent, the adhesion strength can be used as an index when selecting the most suitable liquid injection agent from among multiple liquid injection agents.

The test device used in the grout performance verification test method may include, for example, a container for storing the test specimen and the grout, a suspending means for suspending the stronger one of the test specimen and the hardened body of the grout, and a load meter attached to the suspending means. With this test device, the load value when the contact surface is shifted while either the test specimen or the hardened body is suspended can be measured, so that the adhesion state can be quantitatively confirmed.
It is preferable that the test apparatus further includes a stand provided at the bottom of the container to support the specimen. Such a stand may include a bottom plate and a wall material erected on the bottom plate, with the upper surface of the wall material being in contact with the bottom edge of the specimen. It is further preferable that an air vent pipe communicating with the space surrounded by the wall material is attached to the wall material. In this way, negative pressure can be prevented from being generated between the bottom surface of the specimen and the container, and therefore adhesion between the specimen and the bottom surface of the container can be prevented. In other words, negative pressure can be prevented from being generated by supplying air from the outside into the space of the stand through the air vent pipe.
Furthermore, if the testing equipment is equipped with a lid that covers the upper surface of the container and has an opening through which the specimen can be inserted, it is possible to prevent the hardened body from being pulled up along with the specimen when the specimen is pulled up.

The injection agent performance verification test method and test device of the present invention make it possible to verify whether the injection agent has the desired performance when injected into frozen ground.

FIG. 2 is a cross-sectional view of a test device according to the present embodiment. 2A is a cross-sectional view taken along line AA of the testing device shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along line BB of the testing device shown in FIG. 2 is a flowchart showing the procedure of a fuel agent performance verification test method according to the present embodiment. 1 is a schematic diagram showing the working status of a grout performance confirmation test method, in which (a) is a test specimen preparation work, (b) is a test specimen installation work, (c) is a grout injection work, and (d) is a performance confirmation work. 1 is a load-displacement curve showing an example of a test result, in which (a) is a case where the hardened body is not attached to the test specimen, and (b) is a case where the hardened body is attached to the test specimen. Schematic diagrams showing frozen ground, where (a) is a healthy frozen ground, (b) is a frozen ground with water paths formed, and (c) is a frozen ground that has undergone chemical injection.

In this embodiment, a method for testing to confirm the performance of a grout is described for confirming whether or not the grout can block water paths and ensure water cutoff when the grout is injected into frozen ground where water paths are formed. In the grout performance confirmation test method of this embodiment, adhesion between a test piece 1 cooled below freezing and a hardened body 2 of the grout in contact with the test piece 1 is confirmed. Figures 1 and 2 show a test device 3 used in the grout performance confirmation test method of this embodiment.
As shown in Figure 1, the testing apparatus 3 comprises a container 4 for housing the test specimen 1 and the hardened body 2, a suspending means 5 for suspending the test specimen 1, a load meter 6 attached to the suspending means 5, and a stand 7 provided at the bottom of the container 4 for supporting the test specimen 1.

The container 4 comprises a box-shaped container body 41 with an open top, and a lid 42 that covers the top of the container body 41. The container body 41 of this embodiment is configured with a rectangular bottom and a square cylindrical wall that covers the side. The container body 41 is not limited to a rectangular shape in plan view, and may be a circular shape in plan view. The inner surface of the container body 41 of this embodiment is covered with a heat insulating material 43.
The lid 42 has an opening 44 through which the specimen 1 can be inserted. As shown in Fig. 2(b) , the lid 42 of this embodiment is formed of a pair of plate materials 45, 45. Each plate material 45 has a recess 46 formed on the side facing the other plate material 45. When the recesses 46 of the pair of plate materials 45, 45 are combined with each other, an opening 44 having the same planar shape as the specimen 1 is formed.

As shown in FIG. 1, the suspending means 5 includes a pull rod 51 and a lifting means 52 for lifting the pull rod 51. A part (lower part) of the pull rod 51 is embedded in the specimen 1, and the remaining part (upper part) protrudes from the upper surface of the specimen 1. The upper end of the pull rod 51 is connected to the lifting means 52, so that the specimen 1 is suspended. A fixing part 53 for preventing the pull rod 51 from being pulled out from the specimen 1 is formed at the lower end of the pull rod 51. The fixing part 53 of this embodiment is fixed to the pull rod 51 so as to intersect with the pull rod 51. Note that the fixing part 53 may be, for example, a plate-like member or a rod-like member, or may be an uneven part formed on the outer surface of the pull rod 51, as long as it is possible to improve the bonding with the specimen 1. A locking part 54 is formed at the upper end of the pull rod 51 of this embodiment. The pull rod 51 is connected to the lifting means 52 via the locking part 54.
The lifting means 52 is a device that applies a tensile force to the extraction rod 51, and is attached to the support member 55. The lifting means 52 is composed of a winch or the like, and suspends the extraction rod 51 via a load meter 6. The support member 55 in this embodiment includes a base 56, a support 57, and a cross member 58. The base 56 in this embodiment is a pair of steel members arranged to sandwich the container 4, and constitutes the legs of the support member 55. A holding member 59 is attached to the base 56 via a jig (long bolt, etc.) 59a. As shown in Figures 1 and 2(b), the holding member 59 is arranged on the upper surface of the lid member 42 or the upper end of the container body 41, and controls the movement of the container 4 when the test specimen 1 is lifted. In other words, the holding member 59 is a member that holds down the container 4 from above. The support 57 is a steel member erected on the base 56, as shown in Figure 1. A cross member 58 is horizontally supported on the support 57. The cross member 58 is a steel member that is horizontally supported between the left and right support pillars 57 , 57 above the pulling rod 51 , and supports the lifting means 52 .

As shown in FIG. 1, the load meter 6 is disposed between the pull rod 51 and the lifting means 52. The load meter 6 measures the load when the pull rod 51 is lifted by the lifting means 52.

1, the mount 7 includes a bottom plate 71 and a wall material 72 erected on the bottom plate 71. The upper surface (upper end) of the wall material 72 contacts the edge of the bottom surface of the specimen 1. The outer shape of the wall material 72 in this embodiment is the same as the outer shape of the specimen 1. The mount 7 forms a gap below the bottom surface of the specimen 1.
An air vent pipe 73 is attached to the wall material 72 and communicates with the space surrounded by the wall material 72. The air vent pipe 73 extends to the outside of the container 4.

Next, a grout performance confirmation test method using the test device 3 will be described. The grout performance confirmation test method of this embodiment is shown in Figures 3 and 4. As shown in Figure 3, the grout performance confirmation test method of this embodiment includes a test specimen preparation operation S1, a test specimen installation operation S2, a grout agent injection operation S3, a performance confirmation operation S4, and an adhesion strength calculation operation S5.
In the specimen preparation work S1, a specimen 1 is prepared as shown in Fig. 4(a). In this embodiment, a cylindrical specimen 1 having a diameter of 100 mm and a height of 200 mm is prepared. The specimen 1 is prepared with the lower part of the extraction rod 51 embedded. The specimen 1 in this embodiment is made of ice formed in a columnar shape.

In the specimen installation work S2, as shown in FIG. 4(b), a columnar specimen 1 cooled to below freezing is placed in a container 4. A stand 7 is provided in advance in the container 4, and the specimen 1 is placed on the stand 7. At this time, the specimen 1 is suspended by a suspension means 5 (see FIG. 1) via a load meter 6. In this embodiment, a part of the specimen 1 protrudes above the upper end of the container 4, but the specimen 1 may be entirely contained within the container 4. At this time, the weight (mass) of the specimen 1 is measured by the load meter 6.

In the grout injection operation S3, as shown in FIG. 4(c), the chemical injector 21 is injected (put into) the container 4 so as to be in contact with the specimen 1. That is, the gap between the specimen 1 and the container 4 is filled with the chemical injector 21. After filling with the chemical injector 21, the top surface of the container 4 (chemical injector 21) is covered with the lid 42 (see FIG. 1 and FIG. 2). The lid 42 is fixed with the pressing member 59 (see FIG. 1). At this time, the lid 42 is installed with the specimen 1 inserted through the opening 44.

In the performance confirmation work S4, as shown in FIG. 4(d), the presence or absence of resistance when the contact surface between the specimen 1 and the hardened body 2 of the liquid injection agent 21 is shifted is confirmed. The performance confirmation work S4 is performed after injecting the liquid injection agent 21 into the container 4 and leaving it for a predetermined time (the time required for the liquid injection agent 21 to harden: in this embodiment, about a few seconds). When the liquid injection agent 21 hardens (when the hardened body 2 is formed), the lifting means 52 (see FIG. 1) is operated to lift the specimen 1 and the load when lifting the specimen 1 is measured by the load meter 6. At this time, since the upper surface of the hardened body 2 is covered by the lid material 42, the contact surface between the specimen 1 and the hardened body 2 can be shifted while preventing the hardened body 2 from rising together with the specimen 1. Figure 5 shows the load-displacement curve when the specimen 1 is lifted. As shown in FIG. 5(a), when the hardened body 2 is not attached to the specimen 1, the load remains constant at the same value as the weight of the specimen 1 (including the pull rod 51). On the other hand, when the hardened body 2 is attached to the specimen 1, as shown in FIG. 5(b), the load increases more than the weight of the specimen 1, and when the attachment between the specimen 1 and the hardened body 2 is broken, the load drops sharply, and then the load remains constant at a value approximately equal to the weight of the specimen 1.

In the adhesion strength calculation work S5, the adhesion strength s between the specimen 1 and the hardened body 2 of the liquid grout 21 is calculated. The adhesion strength s is calculated by subtracting the weight _w0 of the specimen 1 measured in the specimen installation work S2 from the load _w1 calculated in the performance confirmation work S4, and dividing the result by the contact area a between the specimen 1 and the liquid grout 21 (hardened body 2) (see formula 1).
By conducting a grout performance confirmation test on a plurality of grouting agents 21 and comparing the adhesion strength s, it is possible to quantitatively determine which grouting agents 21 have superior water-stopping properties.
s=(w ₁ - w ₀ )/a...Formula 1

As described above, the grout performance confirmation test method of this embodiment is to confirm the adhesion between the specimen 1 and the hardened body 2 by confirming the presence or absence of resistance that occurs when the contact surface between the specimen 1 and the hardened body 2 is shifted. In other words, if the resistance is confirmed, it can be determined that the specimen 1 and the hardened body 2 are adhered to each other and the liquid grout agent 21 exhibits the desired performance. Therefore, for example, it can be used as a liquid grout agent when a liquid grouting method is used in combination with the aim of improving the water-stopping property of frozen ground. On the other hand, if there is no resistance, it is presumed that the liquid grout agent 21 does not harden under low temperature conditions or that the surface of the specimen 1 is thawed due to the heat generated when the liquid grout agent 21 hardens. Therefore, it can be determined that the liquid grout agent 21 is not suitable for frozen ground.
Furthermore, according to the injection agent performance confirmation test method of this embodiment, by confirming that the load applied when pulling up the specimen 1 exceeds the weight of the specimen 1, the adhesion state between the specimen 1 and the hardened body 2 can be quantitatively confirmed.
In addition, the adhesion strength can be calculated and used as an index for selecting the most suitable liquid medicine injection agent from among a number of liquid medicine injection agents.

In the test device 3, since the space of the stand 7 is open to the atmosphere via the air vent pipe 73, it is possible to prevent the air in the space of the stand 7 from being cooled and causing negative pressure. In other words, since the stand 7 can prevent negative pressure from being caused between the bottom surface of the test specimen 1 and the container 4, it is possible to prevent adhesive force from being caused between the bottom surfaces of the test specimen 1 and the container 4. Therefore, with the test device 3, it is possible to check only the resistance between the test specimen 1 and the hardened body 2.
In addition, since the test device 3 includes a lid 42 that covers the upper surface of the container 4, when the specimen 1 is pulled up, the hardened body 2 can be prevented from being pulled up together with the specimen 1. As a result, the contact surfaces of the specimen 1 and the hardened body 2 can be shifted.

Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each of the above-described components can be appropriately modified without departing from the spirit of the present invention.
In the above embodiment, the presence or absence of resistance is confirmed by measuring the change in load caused when the contact surface between the specimen 1 and the hardened body 2 is shifted with the load meter 6, but the method of measuring the resistance is not limited. For example, the presence or absence of resistance may be confirmed by the change in resistance when the measurer pulls up the pull-out rod 51.
The configuration of the test device 3 is not limited to that shown in the above embodiment. For example, the lid member 42 may be omitted. Furthermore, the method of fixing the lid member 42 is not limited, and for example, the lid member 42 may be fixed directly to the container body 41 via a jig. Furthermore, the configuration of the hanging means 5 can be changed as appropriate.

In the above embodiment, the specimen 1 is suspended by the suspension means 5, but if the hardened body 2 has a greater strength than the specimen 1, the hardened body 2 may be suspended instead.
In the above embodiment, the specimen 1 is ice, but the material constituting the specimen is not limited, and may be, for example, a columnar member formed of concrete, mortar, or the like. The specimen 1 may also be formed of soil and sand, boring cores, or the like collected on-site. The shape and dimensions of the specimen 1 are not limited, and may be appropriately determined, for example, to be formed into a rectangular column shape.
In the above embodiment, the inner surface of the container body 41 is covered with the heat insulating material 43, but the outer surface of the container body may be covered with the heat insulating material 43. The heat insulating material 43 may be installed as necessary.
The stand 7 may be installed as necessary. For example, the bottom of the container 4 may be formed with projections and recesses to form a space below the bottom surface of the specimen 1.
In the above embodiment, the presence or absence of resistance is measured by lifting up the specimen 1, but the measurement method is not limited to this. For example, the presence or absence of resistance may be measured by lowering the container 4 while the specimen 1 is suspended.

REFERENCE SIGNS LIST 1 Test specimen 2 Hardened body 3 Testing device 4 Container 41 Container body 42 Lid material 44 Opening 5 Suspension means 6 Load meter 7 Stand 71 Bottom plate 72 Wall material 73 Air vent pipe S1 Test specimen preparation work S2 Test specimen installation work S3 Grout injection work S4 Performance confirmation work S5 Adhesion strength calculation work

Claims (6)

A specimen installation operation of placing a specimen cooled below freezing in a container;
an injection agent injection operation of injecting a chemical injection agent so as to contact the specimen;
and a performance confirmation operation for confirming the presence or absence of resistance when the contact surface between the test specimen and the liquid injection agent is shifted. In the specimen installation work, the columnar specimen is placed in the container,
In the grout injection operation, the liquid grout is filled into the gap between the test piece and the container,
2. The grout performance verification test method according to claim 1, wherein the performance verification work includes lifting the test specimen and measuring a load when lifting the test specimen. The injection agent performance verification test method according to claim 2, further comprising an adhesion strength calculation step of calculating adhesion strength by subtracting the weight of the test specimen from the load and dividing the result by the contact area between the test specimen and the liquid injection agent. A test device for confirming adhesion between a specimen cooled below freezing point and a hardened body of a liquid grout injected so as to contact the specimen,
A container for containing the test specimen and the hardened body;
a suspending means for suspending one of the test specimen and the hardened body, whichever has a greater strength;
a load meter attached to the suspension means. The container further includes a stand provided at a bottom thereof to support the specimen,
The stand includes a bottom plate and a wall material erected on the bottom plate,
The upper surface of the wall material contacts the bottom edge of the specimen,
5. The testing device according to claim 4, wherein an air vent pipe communicating with a space surrounded by said wall material is attached to said wall material. A lid material is provided to cover the upper surface of the container,
6. The testing device according to claim 4, wherein the cover member has an opening through which the test piece can be inserted.

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