JP5270650B2 - Permeability test equipment - Google Patents

Description

  The present invention relates to a water permeability test apparatus for measuring water permeability of various grounds.

  For embankment structures (bank bodies) such as pond embankments and river embankments, as one of its important functions, safety against fluctuations in water level and infiltration during rainfall is required. It is the water permeability of the ground that dominates this hydraulic safety, and in order to properly manage and inspect it, a water permeability test device capable of measuring the water permeability of the ground simply and accurately is required. .

  As such a water permeation test apparatus, a structure (E-19 method) as shown in FIG. 7 has been used so far (see, for example, FIG. 1 of Patent Document 1).

  In the water permeability test apparatus 1, for example, as shown in FIG. 7, as a standard example, a cylindrical test hole (vertical shaft) having a diameter of about 0.3 m and a depth of about 0.3 m in the target ground G portion. H is drilled and filled with washed crushed stone S having a diameter of about 10 mm. Next, the test hole water W1 is stored in the test hole H, and the stored water is infiltrated from the bottom surface and the side surface of the test hole H at a constant water level by using a Marriott siphon type test device. Is supposed to measure.

  The Marriott Siphon type test apparatus has an airtight water tank 2 capable of storing water level measurement water W2 in an airtight state, and an opening 4a on one end side in the airtight water tank 2 below the water surface of the water level measurement water W2. In addition, the water injection pipe 4 in which the opening 4b on the other end side is disposed in the test hole H, and the airtight water tank 2 through the water injection pipe 4 when the water level of the test hole water W1 is lowered. The test hole H is replenished with water, and includes a constant water level holding pipe 3 that holds the water level of the test hole water W1 substantially constant, and a water level sensor 5 that measures the water level of the water level measurement water W2. Has been.

  The constant water level holding pipe 3 has an opening 3a on one end side in the airtight water tank 2 and above the water surface of the water for measuring the water level W2, and water for test holes in the test hole H. An opening 3b on the other end side is arranged so as to face W1.

  In this case, since the airtight state in the airtight water tank 2 is maintained while the opening 3b on the other end side of the constant water level holding pipe 3 is closed by the test hole water W1, the water level of the water level measuring water W2 is maintained. However, when the water level of the test hole water W1 is lowered by the permeation into the ground G, the airtight water tank 2 is opened from the opening 3b on the other end side of the constant water level holding pipe 3. Air will enter.

  Thereby, water is replenished from the water injection pipe 4 to the test hole H through the water injection pipe 4, the water level measuring water W2 is lowered, the water level of the test hole water W1 is raised, and the constant water level holding pipe 3 is closed again by the test hole water W1.

  As a result, the airtight water tank 2 becomes airtight again, water injection from the water injection pipe 4 is stopped, and the water level change of the water level measurement water W2 is stopped. Thereafter, since the penetration of the test hole water W1 into the ground G is continued, the above-described phenomenon is repeated, and the water level change of the water level measurement water W2 is measured by the water level sensor 5 described above. . That is, the amount of water decrease (infiltration amount) is measured when the predetermined time has elapsed and the change in the water level is generally constant. Then, the degree of water permeability is determined from the amount of water decrease within the predetermined time.

  In the case of the conventional example of FIG. 7, a lid member that can be opened and closed is disposed at the upper part of the above-mentioned airtight water tank 2 (more precisely, the part above the water surface of the water W2 for water level measurement). When the member 6 is opened, the insertion member 7 can be inserted and removed. The insertion member 7 is disposed so as to have a substantially equal cross-sectional area in the height direction when inserted into the airtight water tank 2. In a state where such an insertion member 7 is inserted into the airtight water tank, the cross-sectional area (horizontal cross-sectional area) of the water level measurement water W2 becomes small, and the water level change of the water level measurement water W2 is sensitive to the water level change of the test hole water W1. become.

  Therefore, for example, when the ground G is hard and the degree of penetration of the test hole water W1 is small, if the insertion member 7 is inserted into the airtight water tank 2, the change in the water level can be measured with high sensitivity. Become. Further, when the ground G is loose and the penetration degree of the test hole water W1 is large, if the insertion member 7 is removed from the airtight water tank 2, the water level change can be measured with an appropriate sensitivity.

  Furthermore, since the above-described insertion member 7 can be inserted and removed without discarding the water W2 for measuring the water level, the work at the site can be simplified. Further, since the lid member 6 is disposed above the water surface of the water level measurement water W2, the water level measurement water W2 is not spilled even when the lid member 6 is opened, and it is troublesome to replenish water. Can be omitted.

Japanese Patent Laying-Open No. 2010-163801 (Specifications, pages 5-6, FIG. 1)

  However, in the case of the conventional water permeability test apparatus, a plurality of parts such as an airtight water tank 2, a constant water level holding pipe 3, and a water injection pipe 4, which are the main body of the apparatus, are required. Each of the water injection pipes 4 must be installed in a state where both ends of the water injection pipe 4 have a predetermined height relationship with each other in the test hole H, and the airtight water tank 2 as the apparatus main body is placed on the ground G. It is necessary to install horizontally.

  Therefore, the apparatus configuration is complicated and difficult to handle, and installation and measurement work are complicated.

  Moreover, since the water level change in the airtight water tank 2 is only indicated as an electrical signal via the water level sensor 5, the actual water penetration state is difficult to understand and difficult to measure.

  Furthermore, in the case of the same device, when trying to measure the water permeability of the shallow layer portion having a depth of a predetermined value or more, it is necessary to dig the test hole H deeply and fill it with water. Necessary. As a result, the airtight water tank 2 for water injection is also enlarged, and the time required for measurement is also increased.

  The present invention was made in order to solve such a problem, and the airtight water tank has a transparent cylindrical structure, and the opening serving as the above-described constant water level holding pipe and water injection pipe is provided on the lower end side of the structure. It is an object of the present invention to provide a water permeation test apparatus capable of measuring water permeability simply and easily by directly installing the airtight water tank at a predetermined height position in a test hole.

  Each invention of the present application is configured to include the following effective problem solving means in order to solve the above-described problems.

(1) The problem-solving means of the invention of claim 1 The problem-solving means of the invention of claim 1 is an airtight water tank made of a transparent cylindrical body serving as an apparatus body, and a sealable provided at the upper end side of the airtight water tank. It consists of a water supply port and a sealable opening provided on the lower end side of the airtight water tank, and the airtight water tank of the same configuration is directly installed at a predetermined height position in a test hole storing a predetermined amount of water, and The opening on the lower end side of the airtight water tank functions as a Marriott Siphon-type constant water level holding pipe and water injection pipe, and the water permeability is measured from the decrease in the amount of water level in the airtight water tank.

  According to such a configuration, the opening provided on the lower end side of the airtight water tank serving as the apparatus main body functions as a constant water level holding pipe and a water injection pipe of the conventional Marriott siphon-type water permeability test apparatus, and the conventional constant water level. No holding pipe or water injection pipe is required.

  As a result, the water permeability test device with the same configuration is basically composed of a single cylinder with a relatively small diameter, which not only greatly reduces cost but also is easy to carry. Therefore, the measurement test work itself becomes remarkably easy because it is sufficient to insert it into the test hole and install it horizontally on the crushed stone.

  Therefore, measurement at a plurality of locations on the same site is easy. Further, if the diameter of the test hole H is increased, a plurality of test devices can be installed, and the present invention can be applied to the ground having a larger water permeability.

  Furthermore, when a constant water storage tank corresponding to a test hole in which the lower end side of the airtight water tank is inserted and installed and a water supply pipe having a predetermined length extending downward from the bottom thereof, a predetermined value drilled by a hand auger or the like is used. The water permeability of the ground at the bottom of the test hole at the above depth can also be easily measured.

(2) Problem solving means of the invention of claim 2 The problem solving means of the invention of claim 2 is the structure of the problem solving means of the invention of claim 1, wherein the airtight water tank portion which is the apparatus body is a transparent body. It is characterized by having.

  According to such a configuration, it is possible to easily confirm that the water is properly permeated and the water permeation state in the measurement state from the rising state of the bubbles in the airtight water tank that is the apparatus main body.

  Therefore, the measurement accuracy is also improved.

(3) The problem solving means of the invention of claim 3 The problem solving means of the invention of claim 3 is the structure of the problem solving means of the invention of claim 2 above, wherein the airtight water tank which is the main body of the device is provided in the water tank. It is characterized in that a water level scale capable of reading a change in the water level is provided.

  According to such a configuration, the decrease in the amount of water in the airtight water tank can be read directly with eyes, and the measurement at the site becomes easy.

  As a result of the above, according to the present invention, the water permeability in various grounds can be measured with a much simpler structure than conventional devices, and the measuring range can be increased by installing a plurality of water inlets. Expanding.

It is a front view which shows the structure of the water-permeable test apparatus which concerns on Embodiment 1 of this invention. It is a top view of the apparatus. It is sectional drawing which shows the structure in the water-permeable test state of the same apparatus. It is a front view which shows the structure in the water-permeable test state of the water-permeable test apparatus which concerns on Embodiment 2 of this invention. It is a front view of the same apparatus. It is a top view of the apparatus. It is sectional drawing in the water-permeable test state which shows the structure of the conventional water-permeable test apparatus.

<Embodiment 1>
1-3 has shown the structure of the water-permeable test apparatus based on Embodiment 1 of this invention.

(Configuration of water permeability test equipment)
First, FIG. 1, FIG. 2 has each shown the structure of the apparatus main-body part of the water permeability test apparatus.

  Moreover, FIG. 3 has shown the whole structure in the use condition in the field of the water permeability test apparatus.

  That is, in the water permeability test apparatus 10 according to the first embodiment, as shown in FIGS. 1 and 2, for example, the above-described airtightness in which the inside of the cylindrical body having a length h1 is formed of a highly transparent acrylic resin is a cavity. An apparatus main body 10a as a water tank, a bottom member 10b having a thickness t1 that forms the bottom of the apparatus main body 10a, and a detachable lid member 10c having a thickness t2 that forms a lid of the apparatus main body 10a. As an example, the first, second, and third water injection ports 11a, 11b, and 11c that gradually decrease in diameter are provided at the end of the apparatus main body 10a on the side of the bottom member 10b. And in a state penetrating from the inside to the outside in the radial direction. These first, second, and third water injection ports 11a, 11b, and 11c are provided with the same height position h2 from the upper surface to the upper end side of each bottom member 10b, A water tap (not shown) that can be freely inserted and removed is provided.

  These first, second, and third water injection ports 11a, 11b, and 11c are adjusted in their opening states (the number of water injection plugs to be extracted) according to the water permeability of the ground G that is the measurement target.

  Each of the bottom member 10b and the lid member 10c has a larger diameter than the apparatus main body 10a, and a flange portion having a predetermined width is formed on the outer periphery thereof. The lid member 10c is detachably fitted to the upper end opening of the apparatus main body 10a, is removed from the upper end of the apparatus main body 10a, and the first, second, and third notes are provided. In a state where the water faucets are set (inserted) in the water ports 11a, 11b, and 11c, the water W2 for measuring the water level is put into the apparatus main body 10a up to the full water level on the upper end side, and then fitted and fixed to be sealed. Is done.

  That is, in this case, the entire upper end side opening of the apparatus main body 10a, which is an airtight water tank, is configured as a water supply port, which is provided with a separate water supply port in a part of the lid member 10c itself. This may be sealed after the water supply by using another seal cap.

  Further, on the outer peripheral surface of the apparatus main body 10a, there is a water scale (water level scale) 13 for reading a change in the amount of water that decreases during a water permeability test in the apparatus main body 10a that is an airtight water tank from the lower end side to the upper end side. Is provided.

  The water permeability test apparatus 10 configured as described above is used by being installed in a vertical state in a test hole H similar to the prior art, for example, as shown in FIG.

(Procedure for installation and measurement of water permeability test equipment)
(1) Creation of test hole As an example, as shown in FIG. 3, a cylindrical test hole (constant water level tank) H having a diameter of about 0.3 m and a depth of about 0.3 m is dug on the target ground G. The radius Ro of the test hole H and the depth Z of the ground surface are measured.

(2) Filling of crushed stones A large number of crushed stones (particle size of about 10 mm) S washed in the test hole H are spread, and a pedestal (rod-shaped legs 15a, 15a,. 15) is installed horizontally.

  (3) A predetermined amount of water is poured into the test hole H as a constant water level tank using a bucket or the like. When the water injection flow rate is stabilized and the water level is substantially constant, for example, as shown in FIG. 3, the water permeability test apparatus 10 having the configuration shown in FIGS. 1 and 2 is placed on the installed base 15 as shown in FIG. It installs in the state which put water W2 for water level measurement in the cavity part 10d of the inside.

  And the level state of the apparatus main body 10a part of the apparatus 10 is confirmed with a level.

(4) Adjust the number of water taps to be removed. Then, according to the water permeability of the measurement target ground G itself, the water level of the water W1 in the test hole H is constant so that the water level of the apparatus main body 10a is constant. The number of pulling out the water taps of the first, second and third water inlets 11a, 11b and 11c provided on the lower end side is adjusted.

  That is, when the water permeability is large due to sand or the like, the water in the test hole H is rapidly reduced, so that the water injection plugs of all the first, second, and third water injection ports 11a, 11b, and 11c are correspondingly provided. When the water permeability is small, the water injection amount is reduced by removing only the water injection plug of only the third water injection port 11c.

(5) Main test Then, when the water injection flow rate in the test hole H becomes constant, the measurement test is started.

  In the measurement test, the passage of a certain time and the amount of change (decrease) in the water level in the apparatus main body 10a, which is an airtight water tank, are read about three times. Then, for example, the water permeability of the ground G is determined based on the average value thereof.

  Of course, in this case, if one of the three readings is abnormal, a retest is performed and the test is repeated until the three values become substantially the same.

(Structural features and effects)
According to the above configuration, each of the first, second, and third water injection ports 11a, 11b, and 11c provided on the lower end side of the apparatus main body 10a, which is an airtight water tank, has the conventional water permeability test apparatus described above (see FIG. The functions of the constant water level holding pipe 3 and the water injection pipe 4 of 7) are exhibited, and the conventional pipes 3 and 4 are not required at all.

  As a result, the water permeability test apparatus 10 according to the present embodiment is composed of a single cylinder having a relatively small diameter, which not only greatly reduces the cost but also is easy to carry. Since it is sufficient to insert it into the test hole H as a constant water level tank for G and install it horizontally on the crushed stone S, the measurement test work itself becomes remarkably easy.

  Therefore, measurement at a plurality of locations on the same site is easy. Further, if the diameter of the test hole H is increased, a plurality of test devices can be installed, and the present invention can be applied to the ground having a larger water permeability.

  Furthermore, in the same configuration, the apparatus main body 10a portion which is an airtight water tank of such a cylindrical water permeability test apparatus 10 is a transparent body made of a resin material such as acrylic resin throughout.

  Therefore, as well as being lightweight, as shown in FIG. 3, in the measurement state, the water is properly permeated into the ground G and the state of water permeation is the rising state of bubbles in the apparatus main body 10a which is an airtight water tank. Can be easily confirmed. Therefore, the measurement accuracy is also improved.

(Modification 1)
In the above configuration, the permeation test apparatus 10 and the pedestal 15 having a level adjusting function for placing the permeation test apparatus 10 are configured as separate objects, and first the pedestal 15 having leg portions 15a, 15a. Was installed in the test hole H, the level was adjusted by a level, and the water permeability test apparatus 10 was installed thereon.

  However, this is provided with three (or four) leg portions 15a, 15a,... That can be inserted into the crushed stone S on the bottom member 10b itself on the lower end side of the apparatus main body 10a, while the lid member 10c on the upper end side is provided. The water permeability test apparatus 10 itself may be installed directly in the test hole H by providing a level on the upper surface.

  With such a configuration, the configuration becomes simpler, and installation work and measurement work become easier.

(Modification 2)
Moreover, in the above-described configuration, the sizes of the first, second, and third water injection ports 11a, 11b, and 11c are changed, but the same effect can be obtained even if all of them have the same diameter. Moreover, the number of water inlets can be further increased.

(Modification 3)
Note that it is not always necessary to provide a plurality of the water injection ports, and for example, a single water injection port can be formed. And the shape is also arbitrary.

<Embodiment 2>
Next, FIGS. 4-6 has shown the structure of the water-permeable test apparatus based on Embodiment 2 of this invention.

  This water permeability test apparatus 10 uses a hand auger or the like to dig a small-diameter test hole H up to a predetermined depth portion of the ground G to be measured, and a predetermined amount only in a small volume space portion at the bottom. Water is stored so that the water permeability of the ground at the same depth can be measured.

  In this case, since the inner diameter of the test hole H cannot be increased and the water permeability test apparatus 10 itself cannot be inserted into the test hole H, for example, as shown in FIG. A constant water level tank 16 on which the water permeability test apparatus 10 can be installed is installed on the ground G, and a water pipe 17 having a diameter and a length corresponding to the depth of the test hole H is connected to the lower center of the identified water level tank 16. The water in the constant water level tank 16 is supplied and stored in the lower part of the test hole H through the water supply pipe 17.

  The constant water level tank 16 has a height (depth) and a diameter suitable for vertically installing the lower end side of the water permeability test apparatus 10 having the same configuration as that of the first embodiment described above in a immersed state with a predetermined depth. (Inner diameter) is formed by a bottomed, equal-diameter cylindrical body, and on its inner wall, there are four locking plates in the circumferential direction on which the outer peripheral side flange portion of the bottom member 10b of the water permeability test device 10 is placed. 16a, 16a, 16a, 16a are provided.

  And the water permeability test apparatus 10 is horizontally mounted on this latching plate 16a, 16a, 16a, 16a via the bottom member 10b.

  Further, a water supply port 16b penetrating in the vertical direction is provided at the center of the bottom of the identified water level tank 16, and the upper end side opening 17a of the water supply pipe 17 described above is screwed inward and connected to the lower surface side thereof. A cylindrical socket member 16c provided with a thread groove 18 is provided.

  And the upper end side opening part 17a of the said water supply pipe | tube 17 is screwingly connected with respect to this socket member 16c.

  The water supply pipe 17 is provided with a plurality of water injection ports 17c, 17c,... On the entire peripheral surface on the lower end portion 17b side, and the water supply pipe 17 is provided in the constant water level tank 16 through the water injection ports 17c, 17c,. While the water W1 is poured into the test hole H (H1), a cylindrical water-stop packer 20 into which air is injected from the outside is fitted (externally fitted) along the way. The water-stop packer 20 is made of a flexible hollow member made of, for example, a rubber tube that can freely expand and contract in the radial direction, and a small-diameter air hose 21 made of a flexible pipe member is provided on the upper end side thereof. It has been. And this air hose 21 is derived | led-out on the ground G via the space part H2 without the water above the test hole H mentioned above, and is supplied from an external electric air pump (illustration omitted) as needed. Air is injected into the water stop packer 20 to bulge the water stop packer 20 in and out in the circumferential direction, and between the lower side water storage part H1 and the upper side space part H2 in the test hole H. To seal. And water W1 is stored only by the bottom part of the test hole H by it.

  Therefore, also in this case, when the water W1 in the water storage portion H1 decreases due to the penetration of the water into the lower soil of the test hole H, the water W1 in the constant water level tank 16 passes through the water pipe 17. Since water is fed into the water reservoir H1, the water W1 in the constant water level tank 16 is reduced, and the first, second and third water injection ports 11a, 11b on the lower end side of the apparatus main body 10a of the water permeability test apparatus 10 are reduced. , 11c, water W2 in the apparatus main body 10a of the water permeability test apparatus 10 is poured.

  As a result, the amount of water in the apparatus main body 10a decreases, and the degree of water permeability in the depth portion of the target ground G at the predetermined depth is measured from the degree of decrease in each amount of water confirmed a plurality of times over a certain period of time.

  When the measurement is completed, first, the main body of the water permeability test device 10 in the constant water level tank 16 is taken out, and then the air hose 21 is used to evacuate the water-stopping packer 20 to shrink the water-stopping packer 20 and further test. The water supply pipe 17 is removed from the hole H to remove the water stop packer 20, and the connection with the constant water level tank 16 is released, and each is stored in a predetermined place.

  According to such a configuration, it is possible to easily measure the water permeability of the shallower shallower portion in the same manner as in the case of the first embodiment of the measurement ground G to be measured.

<Embodiment 3>
In the configuration of the first and second embodiments described above, the change in the amount of water in the apparatus main body 10a within a predetermined time is read from the scale on the water scale 13 and is input as predetermined measurement data to a predetermined data logger or a personal computer. By doing so, the water permeability is measured.

  However, this is because, for example, a float is provided on the water surface in the apparatus main body 10a, and a water level detector such as a potentiometer that generates a water level signal according to the elevation level of the float is provided to record water level data such as a data logger. If the means is automatically input, the measurement work is further facilitated.

  10 is a water permeability test apparatus, 10a is an airtight water tank, 10b is a bottom member, 10c is a lid member, 11a to 11c are first to third water inlets, 13 is a water volume scale, G is ground, and S is crushed stone. It is.

Claims (3)

  An airtight water tank made of a transparent cylindrical body as the apparatus main body, a sealable water supply port provided on the upper end side of the airtight water tank, and a sealable opening provided on the lower end side of the airtight water tank. The airtight water tank of the configuration is directly installed at a predetermined height position in a test hole storing a predetermined amount of water, and the opening on the lower end side of the airtight water tank functions as a Marriott siphon type constant water level holding pipe and water injection pipe, A water permeability test apparatus characterized in that water permeability is measured from a decrease in the amount of water level in an airtight water tank.   The water permeability test apparatus according to claim 1, wherein the airtight water tank portion which is the apparatus main body is a transparent body.   3. The water permeability test apparatus according to claim 2, wherein the airtight water tank which is the apparatus main body is provided with a water level scale capable of reading a change in the water level in the water tank.

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