JP2019002881A - Testing water injection device and testing water injection method - Google Patents

Abstract

To provide a testing water injection device which can inject water in response to volume of water of wide range, and to provide a water injection method therewith.SOLUTION: A testing water injection device injects water into a sample and comprises an outside tank, multiple buret, water filling pipe and compression means. The compression means pressurizes inside of the outside tank. The multiple buret are arranged in the outside tank, and the water filling pipe is connected to the tip of the burette. The upper part of the burette opens (is thrown open), and therefore the inside of the burette takes pressure same as the outside tank. Water in the multiple buret flows in the same water filling pipe.SELECTED DRAWING: Figure 1

Description

  The present invention is a technique related to a test for confirming the water permeability of a test body by pouring water, such as a water permeability test, and more specifically, a test water injection apparatus capable of supporting a wide range of water injection amounts, and the use thereof. It relates to the water injection method.

  The existence of groundwater greatly affects the stability of structures built on the ground and the ground itself. When rainwater permeates the ground and the groundwater level rises, slope collapse and landslides may be induced. When the groundwater level is locally lowered due to groundwater pumping, the structure on the ground becomes unstable. In addition, groundwater is one of the requirements that must always be considered in construction work. For example, when excavation work such as a tunnel is performed, it is necessary to take measures against springs during excavation depending on the groundwater level, and at the same time, it is necessary to consider the lowering of the surrounding groundwater level.

  Therefore, it is not uncommon for ground surveys to be performed for construction work and geological surveys in landslide areas to check groundwater levels and conduct ground permeability tests. Alternatively, bentonite mixed soil may be installed around the concrete pit containing the waste for the purpose of reducing the advection speed of groundwater. Permeability tests may be performed. This water permeability test is a test for obtaining a water permeability coefficient by pouring water into a specimen, and is usually carried out by a technique shown in Japanese Industrial Standards (JIS A1218 soil water permeability test method). The water permeability test can be classified into two types: a constant water level permeation test performed on a test body having a relatively high water permeability and a water level permeation test performed on a test body having a small water permeability.

  As described above, the water permeability test is one of the tests frequently used in various scenes, and various improved techniques related to the water permeability test have been proposed so far. For example, Patent Document 1 proposes a technique for performing a water permeability test on a test body in which a torsional force is loaded in addition to a lateral pressure and an axial pressure in order to reproduce a local stress state as much as possible.

JP 2004-37261 A

  In general, the permeability test is a test performed for the purpose of obtaining the permeability coefficient of the ground, and there have been many proposals for improved techniques based on the premise that the test body is the ground. Since the value of the permeability coefficient of the target ground can be expected to be within a certain range, the approximate water injection amount used in the permeability test can also be predicted in advance. For this reason, there have been few proposals for improved techniques related to water injection in the water permeability test, and as shown in Patent Document 1, it has been mainstream to use a double-pipe burette as water injection means.

  On the other hand, there are cases where it is desired to grasp the water permeability (or difficult water permeability) of objects other than the ground. For example, a water injection test may be performed for the purpose of investigating voids inside concrete due to cracks or the like. Based on the progress and results of the water injection, the void conditions inside the concrete, which is the specimen, are assumed. However, when water is poured into concrete, a large amount of water injection is required if there are many spaces or voids such as cracks developing inside, but if the inside is solid, it ends with a very small amount of water injection, etc. It is difficult to predict the amount of water injection in advance. In other words, when a water injection test is performed on a concrete body, there is a possibility of water injection in a wide range (so-called wide range), and therefore water injection with various water amounts must be assumed. However, conventional double tube burettes can only be poured in a very limited range, and no technology has been proposed so far that can be poured in response to various amounts of water.

  An object of the present invention is to solve the problems of the prior art, that is, to provide a test water injection apparatus that can inject water corresponding to a wide range of water amount and a water injection method using the same.

  The present invention was made by paying attention to the fact that a plurality of burettes are arranged in the outer tank in order to inject water corresponding to various amounts of water, and is an invention made based on an unprecedented idea. is there.

  The test water injection apparatus of the present invention is an apparatus that injects water into a test body and includes an outer tank, a plurality of burettes, water injection pipes, and pressurizing means. This pressurizing means pressurizes the inside of the outer tank. The plurality of burettes are disposed in the outer tank, and the water injection pipe is connected to the tip of the burette. The burette is open at the top (i.e., open), so that the inside of the burette is subjected to the same pressure as in the outer tank. Moreover, the water in a plurality of burettes flows into the same water injection pipe.

  The test water injection apparatus of the present invention may be provided with an opening / closing means (valve) between the burette and the water injection pipe. In this case, the water in the burette with the opening / closing means opened among the plurality of burettes flows into the water injection pipe, and the water level in the burette with the opening / closing means opened is the same.

  The test water injection apparatus according to the present invention may include a plurality of burettes having different inner diameters.

  The test water injection method of the present invention is a method of water injection to a test body using the above-described test water injection device. That is, water in a plurality of burettes is injected into the test body through the water injection pipes by being pressurized by the pressurizing means.

The test water injection apparatus and the test water injection method of the present invention have the following effects.
(1) Since water can be injected into a wide range of water amounts with one device, a water injection test can be performed without selecting a specimen. Moreover, it is not necessary to perform a large setup change and the test can be performed efficiently.
(2) Since the magnitude of the pressure (back pressure) applied to the outer tank can be arbitrarily set by the pressurizing means, delicate water injection adjustment is also possible.
(3) If various burettes having different inner diameters are arranged in the outer tank, it is possible to inject water into the specimen with various water amounts.

The model figure which shows typically the test water injection apparatus of this invention. The top view which shows six burettes arrange | positioned so that a predetermined space | interval may be maintained according to the planar shape of an outer side tank. The model figure which shows that the water level in the burette where the burette valve was opened is the same. The model figure which shows the test water injection apparatus which has arrange | positioned the several bullet from which a pipe diameter differs, respectively. The model figure which shows the condition which is implementing the test water injection method of this invention.

  The example of embodiment of the test water injection apparatus of this invention and the test water injection method is demonstrated based on figures. The test water injection method of the present invention is a method performed using the test water injection apparatus of the present invention. Therefore, first, the test water injection apparatus of the present invention will be described, and then the test water injection method of the present invention will be described.

1. Test Water Injection Device FIG. 1 is a model diagram schematically showing a test water injection device 10 of the present invention. As shown in this figure, the test water injection apparatus 10 includes an outer tank 20, a plurality of burettes 30 arranged in the outer tank 20, and a pressurizing means 40 that pressurizes the outer tank 20 (not shown in this figure), The water injection pipe 50 is included. Hereinafter, it demonstrates in detail for every main element which comprises the test water injection apparatus 10 of this invention.

(Outside tank)
The outer tank 20 is a substantially cylindrical container (tank), and is mainly formed of a side wall 21, a top board 22, and a bottom board 23 as shown in FIG. For example, the side wall 21 has a cylindrical shape, and the top plate 22 and the bottom plate 23 in this case have a disk shape. A space (hereinafter referred to as “internal space”) formed inside the outer tank 20 is sealed by the top 22 and the bottom 23 so that the atmospheric pressure is maintained (that is, in an airtight state). Has been. Of course, if the internal space can be made airtight, the side wall 21 can have various shapes other than a cylindrical shape, and the top panel 22 and the bottom panel 23 also have a shape that matches the shape of the side wall 21 (particularly the shape in plan view). Can be.

(burette)
A plurality of bullets 30 are arranged in the outer tank 20. In FIG. 1, six burettes 30a to 30f are arranged. However, the number is not limited to this, and an appropriate number of two or more burettes 30 can be arranged. In FIG. 1, six burets 30 a to 30 f appear to be arranged in a horizontal row, but in practice, as shown in FIG. 2, a predetermined interval is maintained in accordance with the planar shape of the outer tank 20. Placed in.

  The burette 30 has a space for storing water therein, and an upper portion thereof is open. Since the upper portion of the burette 30 is open, the inside of the burette 30 (particularly the water head) is in the same pressure state as the inner space of the outer tank 20. Further, the tip (lower end) of the burette 30 has a tapered shape and is open like the upper part, and the water stored inside flows out through the tip opening. Here, for the sake of convenience, the water stored inside the burette 30 is referred to as “burette water”, and the water stored inside the outer tank 20 (but outside the burette 30) as shown in FIG. This is called “tank water”.

  The water guide pipes 61 are connected to the front end openings of the six burettes 30a to 30f, respectively, and an opening / closing means (hereinafter referred to as a “bullet valve 62”) is provided in the middle part of each of the water guide pipes 61. Yes. The water guide pipe 61 is for passing the burette water out of the outer tank 20, and thus penetrates the bottom plate 23, but the airtight state of the internal space is maintained, and the tank water is out of the outer tank 20. It has a penetration structure that does not leak.

  The bullet valve 62 adjusts the flow of the bullet water. That is, when the burette valve 62 is opened, the burette water of the burette 30 is passed through the water conduit 61, and when the burette valve 62 is closed, the burette water of the burette 30 is stopped. In FIG. 1, the burette valves 62 are provided for the six burettes 30a to 30f, respectively. However, the burette valves 62 are not limited to this, and the burette valves 62 are provided so as to collectively adjust the water conduits 61 of the plurality of burettes 30. You can also. For example, a burette valve 62 is installed at a position where the burette 30a, the burette 30b, and the water guide pipe 61 of the burette 30c are integrated, and the burette water of the burettes 30a to 30c is collectively passed according to opening and closing of the burette valve 62, or The water is stopped. As will be described later, when water is poured using two or more test water injection devices 10, the bullet valve 62 is located at a position where all (six in FIG. 1) bullets 30 in one test water injection device 10 are integrated. Can also be provided.

(Water injection pipe)
As shown in FIG. 1, the water guide pipes 61 connected to the six burettes 30 a to 30 f are all connected to the same water injection pipe 50. In other words, all of the burette water of the six burettes 30 a to 30 f finally flows into one water injection pipe 50. And the burette water which flowed through the water injection pipe 50 is inject | poured into the test body set | placed at the front-end | tip (water injection port) of the water injection pipe 50. FIG. Since the six water pipes 61 are connected to one water pipe 50, the water pipes 61 and the water pipes 61 to 30 with the burette valve 62 opened have the same internal pressure. The water level of the burette water in which 62 is opened becomes equal. For example, in FIG. 3, the bullet valves 62 of the bullets 30a and 30f are closed, the bullet valves 62 of the bullets 30b to 30d are opened, and the bullet water of the bullets 30b to 30d shows the same water level.

(Pressurizing means)
The pressurizing means 40 pressurizes or depressurizes the inside of the outer tank 20 (internal space) using a gas (gas) such as air. For example, an air compressor (compressor) can be used. Compressed air (that is, gas pressure) by the pressurizing means 40 is sent to the internal space through the air supply pipe 41. Therefore, the air supply pipe 41 penetrates the top board 22, but of course has a penetration structure in which the airtight state of the internal space is maintained. Note that a pressure valve 42 may be provided in the middle of the air supply pipe 41, and pressurization (decompression) may be adjusted by opening and closing the pressure valve 42. Moreover, you may install the pressure gauge 43 for confirming the pressure state of internal space.

(Differential pressure gauge)
The test water injection device 10 may be provided with a differential pressure gauge 70. The differential pressure gauge 70 is an instrument that directly measures the difference between the pressure in the outer tank 20 (internal space) and the pressure in the water injection pipe 50. Specifically, the tank water passage pipe 71 for passing the tank water is connected to the differential pressure gauge 70, and the water injection pipe 50 is connected to the differential pressure gauge 70, so that the pressure applied to the tank water and the internal pressure of the water injection pipe 50 can be reduced. Measure and determine the pressure difference between the two. The tank water passage pipe 71 penetrates the bottom plate 23, but has a penetrating structure in which the airtight state of the internal space is maintained, like the water guide pipe 61 and the pressurizing means 40. A drain valve 72 is provided in the vicinity of the tip (discharge port) of the tank water passage pipe 71. When the test is completed, the drain valve 72 is opened to drain the tank water in the internal space to the outside.

(Adjustment of water injection volume)
The test water injection device 10 can adjust the amount of water injected into the specimen (hereinafter referred to as “water injection amount”) while performing the test. Specifically, the number of burettes 30 to be poured is increased or decreased by opening / closing the burette valve 62. For example, as shown in FIG. 3, at the beginning of the test, water is poured into the specimen using four burettes 30b to 30e, but the number of burettes 30 to be poured is increased to six or reduced to two depending on the situation. That is why.

  Further, if the pipe diameters (inner diameters) of the plurality of burettes 30 arranged in the outer tank 20 are different from each other, it is preferable that the water injection amount can be finely adjusted. FIG. 4 is a model diagram showing the test water injection apparatus 10 in which a plurality of burettes 30 each having a different pipe diameter are arranged. In this figure, the burette 30c having the maximum diameter is disposed in the center of the outer tank 20, and the two burettes 30a and burette 30e having the minimum diameter are disposed near the side wall 21 in the outer tank 20, Two burettes 30b and burette 30d having a diameter are arranged between the maximum diameter burette 30c and the minimum diameter burettes 30a and 30e. In this case, for example, at the beginning of the test, water is poured into the specimen using the two intermediate diameter burettes 30b and 30d, but when the amount of water injection is increased by a small amount, the minimum diameter burette 30a (30e) is additionally used, which is slightly larger. When the water injection amount is increased, the maximum diameter burette 30c is additionally used.

2. Test Water Injection Method Next, the test water injection method of the present invention will be described with reference to FIG. FIG. 5 is a model diagram showing a situation in which the test water injection method of the present invention is implemented. The test water injection method of the present invention is a method performed using the test water injection device 10 described so far, and therefore, the description overlapping with the content described in the test water injection device 10 is avoided, and the test water injection method of the present invention is applied. Only the specific contents will be explained. That is, the contents not described here are the same as those described in the test water injection apparatus 10.

  In FIG. 5, a water injection test is performed on a concrete body Co as a test body, and two test water injection apparatuses 10 are used for water injection. The test water injection method of the present invention can be performed using two test water injection devices 10 as shown in this figure, or can be performed using only one test water injection device 10, or three or more. The test water injection apparatus 10 can be used.

  The two test water injection devices 10 shown in FIG. 5 are installed on the stand St, and a differential pressure gauge 70 is provided for each. These two test water injection devices 10 are connected to the pressurizing means 40 (for example, a compressor). More specifically, after the air supply pipe 41 connected to the pressurizing means 40 is relayed by the regulator 80, each test water injection is performed. It is connected to the device 10. Therefore, the gas pressure delivered from the pressurizing means 40 passes through the pressurization route Ra1 to the regulator 80, and further passes through the branching pressurization route Ra2 and the pressurization route Ra3. Sent in.

  On the other hand, an insertion pipe 91 is inserted into the concrete body Co from above. A water injection valve 92 and an air vent valve 93 are provided above the insertion pipe 91, and the water injection valve 92 is connected to the tip (water injection port) of the water injection pipe 50. Of course, the water injection pipe 50 is connected to two test water injection apparatuses 10. Therefore, the burette water sent out from the two test water injection devices 10 joins in the middle and then is sent into the insertion pipe 91 through the water injection route Rw.

  Hereinafter, a test water injection method for injecting water into the concrete body Co using the two test water injection devices 10 shown in FIG. 5 will be described. First, the inside of the outer tank 20 is brought into an airtight state with water accumulated in a plurality (twelve in the figure) of the burettes 30. Then, the operation of the pressurizing means 40 is started, and the inside of the two test water injection apparatuses 10 is pressurized while being adjusted by the regulator 80. At this time, it is good also as pressurizing only the inside of one test water injection apparatus 10 initially.

  When the inside of the test water injection apparatus 10 is pressurized, a predetermined number of burette valves 62 are opened, and burette water is passed through the water injection pipe 50. At this time, the burette valve 62 of only one of the test water injection devices 10 may be selected. Then, the burette water is sent into the insertion pipe 91 via the water injection route Rw and further injected into the concrete body Co. After water injection is started, the water level in the burette 30 with the burette valve 62 opened is monitored. If the water level drops more than expected, the burette valve 62 is further opened to increase the burette 30 to be injected. On the other hand, when the water level does not drop more than expected, the opened burette valve 62 can be closed to reduce the number of burettes 30 to be poured.

  Although FIG. 5 shows an example in which water is poured from above the concrete body Co, the present invention is not limited to this. Water can be poured from the side of the concrete body Co, or water can be poured from below the concrete body Co. it can. Moreover, the test water injection method of this invention can be implemented not only when injecting water to the concrete body Co, but also when conducting a water permeability test on soil.

  The test water injection device and the test water injection method of the present invention can be used for investigation of the internal condition of an aged concrete structure, as well as a constant water level water permeability test performed on a ground with high water permeability, and a low water permeability. It can also be used for the water level permeability test performed on the ground. According to the present invention, since it is possible to grasp the deterioration state of a concrete structure in service, it is possible to perform repairs and reinforcement measures according to the situation, and in turn, it will lead to a long life of the concrete structure. It can be said that the invention can be expected not only to make a great contribution but also to society.

DESCRIPTION OF SYMBOLS 10 Test water injection apparatus of this invention 20 Outer tank 21 Side wall (outside tank) Side wall 22 (Outside tank) Top plate 23 (Outside tank) Bottom plate 30 Bullet 40 Pressurizing means 41 Supply pipe 42 Pressure valve 43 Pressure gauge 50 Injection pipe 61 Water guide pipe 62 Bullet valve 70 Differential pressure gauge 71 Tank water flow pipe 72 Drain valve 80 Regulator 91 Insertion pipe 92 Water injection valve 93 Air vent valve Co Concrete body St Mount Ra Ra Pressurization route Rw Water injection route

Claims (4)

In the device that injects water into the test body,
An outer tank,
A plurality of burettes disposed in the outer tank;
A water injection pipe connected to the tips of the plurality of burettes;
Pressurizing means for pressurizing the inside of the outer tank,
The inside of the burette with the top opened is subjected to the same pressure as in the outer tank,
The water in the plurality of burettes flows into the same water injection pipe,
Test water injection device characterized by that. An opening / closing means is provided between the burette and the water injection pipe,
Of the plurality of burettes, water in the burette with the opening and closing means opened flows into the water injection pipe, and the water level in the burette with the opening and closing means opened is the same.
The test water injection apparatus according to claim 1, wherein: The plurality of bullets have different inner diameters,
The test water injection apparatus according to claim 1 or 2, characterized in that In the method of injecting water into a test body using a test water injection device,
The test water injection apparatus includes an outer tank, a plurality of burettes disposed in the outer tank, a water injection pipe connected to the tips of the plurality of burettes, and a pressurizing unit that pressurizes the inside of the outer tank. And the inside of the burette, which is open at the top, is subjected to the same pressure as in the outer tank, and the water in the plurality of burettes flows into the same water injection pipe,
Water in the plurality of burettes is injected into the specimen through the water injection pipe by pressurizing with the pressurizing means;
A test water injection method characterized by that.

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