JPH1161791A - Water permeability test device and water permeability test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure horizontal permeability in the site ground. SOLUTION: The perimeter of a side wall section 11 having a through-hole 12 of a cylindrical body 10 driven into the ground G of a site is excavated to form a ditch 70. A shaft 60 is excavated in the vertical direction at the center position of the cylindrical body 10. After the excavation of the shaft 60, a cover member 20 is provided to the cylindrical body 10, and water is supplied into the cylindrical body 10 after it communicates with a buret 30a to be separately prepared. At the same time, water is supplied into the ditch 70, and the water level is kept in a certain state. Water is infiltrated into the peripheral surface ground G1 surrounding the shaft 6 from the inside of the shaft 60 in the horizontal direction, and coefficient of water permeability in the horizontal direction is obtained by a specific formula from a permeable amount of water after the peripheral surface ground G1 is saturated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-situ permeability test for in-situ examination of horizontal (perpendicular to the compaction surface) permeability of an embankment formed by compacting a soil material such as a fill dam or an earth dam. About technology.

[0002]

2. Description of the Related Art Fill dams and earth dams constructed on soft ground must be designed and constructed in consideration of the functions and economics of the dam within a range that satisfies the safety against sliding failure and deformation. No. To do so, it is necessary to carry out the work after thoroughly examining and understanding some conditions given to the construction of each dam.

[0003] In the construction of such a fill dam or earth dam, since all or a part of the embankment is formed by cutting, the permeability test after the embankment is compacted is an important test item.

[0004] Conventionally, the water permeability at the site of an embankment such as a fill dam or an earth dam is measured in a hole when water flowing at a constant head into a shallow well dug by an auger or the like from the ground surface to a steady state. It is determined by measuring the water level and discharge.

[0005]

However, the permeability obtained by the above-mentioned conventional method is based on the assumption that the permeability of the embankment is constant regardless of the direction, that is, assuming the isotropy of the permeability. It is required after doing.

However, the water permeability of the ground such as embankments formed by compaction differs depending on the direction, and generally, the permeability in the direction parallel to the compaction surface is greater than the direction perpendicular to the compaction surface. The water permeability is different between the horizontal direction and the vertical direction with respect to the compacted surface. In this regard, the conventional water permeability test method employs a method of estimating the water permeability in the horizontal direction with the water permeability in the vertical direction with respect to the compacted surface, assuming the isotropy of the water permeability.

In a fill dam or an earth dam for storing water, it is important to know the water permeability in a direction parallel to the horizontal compaction surface, that is, in the horizontal direction, and a technical development for testing such water permeability has been desired. .

It is an object of the present invention to provide a water permeability test apparatus capable of examining horizontal water permeability in a site ground such as an embankment formed by compaction.

Another object of the present invention is to provide a water permeability test method capable of examining the horizontal water permeability of a site ground such as an embankment formed by compaction.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0011]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, in the water permeability test apparatus and the water permeability test method of the present invention, the amount of water permeability in the horizontal direction on the ground at the site to be measured can be checked at the original position of the ground.

[0013] In the water permeability test apparatus of the present invention, a cylindrical body such as a cylinder having a through hole in a side wall portion is formed on a ground surface such as an embankment ground on the site, and the side wall portion provided with the through hole is positioned above the ground surface. Drive down. When driving the cylinder, the driving is performed such that the cylinder is in the vertical direction.

At the center position of the cylindrical body driven into the ground surface, a vertical shaft is dug in a vertical direction along the center axis direction in the ground inside the cylindrical body by a suitable drilling machine such as a drill or an auger. Excavation is performed so as to form a column-shaped shaft with a predetermined diameter and a circular section.

At the same time, the outer periphery of the side wall portion having a through hole which is driven below the ground surface is excavated in a moat shape. At the time of excavation, the through hole portion of the side wall portion is completely exposed.
Further, in relation to the shaft, the depth of the shaft is set to be deeper than the position of the lowermost through hole in the side wall portion.

In this manner, the shaft is excavated vertically downward along the center axis of the cylindrical body driven into the site ground, and the moat is excavated around the outer periphery of the side wall provided with the through-hole. The water is poured so as to exceed the height of the side wall having the through hole in the shaft at the center of the body.

At the same time, water is also poured into the moat to such an extent that the side wall portion having the through hole is at least submerged. In addition, measures will be taken to keep the water level in the moat constant. For example, an overflow portion may be provided on the ground around the moat so that the water in the moat does not change above the overflow surface.

As described above, while maintaining the water level in the moat on the outer periphery of the side wall portion having the through-hole of the cylindrical body constant, the vertical shaft side in the cylindrical body is set to the high water level, and Water is radiated radially (in all directions) from the through hole to the through hole provided in the side wall. After the water permeation state is continued for a while, after the outer peripheral ground is saturated, the water permeation amount is measured to determine the water permeation in the horizontal direction.

Water is injected into the cylinder by, for example, driving the cylinder into a vertical shaft along the central axis thereof, and then opening the lid above the ground surface of the cylinder with a lid having a through hole. A member is attached, and the through-hole portion is communicated with a container having a known liquid level such as a burette (having a cross-sectional area a) of a measuring container by a communication means such as a rubber tube, so that the state of water injection can be checked. Water may be injected into the container while being able to grasp it.

In this manner, the water permeability test device is set, water is injected into the shaft from the inside of the container to saturate the outer peripheral ground, and then through the outer peripheral ground from the inside of the vertical shaft to the through hole in the side wall portion. By measuring the amount of water permeating through the ground, the horizontal permeability of the measured ground may be determined.

At the start of the measurement of the amount of permeated water after saturation of the outer peripheral ground t
_If the water head from the water level in the moat in the measuring vessel at ₁ is H ₁ and the water head from the water level in the moat in the measuring vessel at time t ₂ is H ₂ at the end of the measurement, the cylinder is assumed to be a cylinder having an inner diameter R _{0 in} advance Jo to form, drill sets a side wall having a through hole at a height H _s, to form a measuring vessel straight tube cross-sectional area a, the same time the vertical shaft to the cylindrical straight pit radius R _i By doing so, the hydraulic conductivity k can be obtained by the following equation.

K = (2.303) ² · a · log ₁₀ (R ₀ / R ₁ ) · log
₁₀ (H ₁ / H ₂ ) / 4 · π · Hs · (t ₂ −t ₁ ) Note that in the above formula, R ₀ originally represents the outer diameter of the measurement sample, but in the present invention, It can be regarded as the same as the inner diameter R _{0 of the} cylindrical body.

Also, H _S in the formula originally represents the height of the sample. However, in the present invention, since the side wall portion having the through hole is a water permeable portion, the height H S of the side wall portion is used. _S can be considered the same as the sample height.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) In this embodiment, a water permeability test apparatus of the present invention will be described.

The cylinder 10 constituting the water permeability test apparatus is shown in FIG.
As shown in the figure, the cylindrical member is formed in a straight cylindrical shape having a constant radius _R0 . The radius R ₀ only needs to be constant so that the cylindrical body 10 has a straight cylindrical shape.

Further, as shown in FIG. 2, drainage through holes are provided at equal intervals on the left and right sides and at equal intervals on the upper and lower sides of the side wall 11 corresponding to the intermediate position between the upper and lower ends of the cylindrical body 10. 12
Are provided horizontally through the side wall portion 11. In the present embodiment, the through hole 12 is formed in a circular shape, and the side wall 11
Are provided uniformly over the entire circumference.

For example, as shown in FIG. 2, in this embodiment, the through-holes 12 are formed by five through-hole rows 1 provided at equal intervals in the vertical direction.
2a and four through-hole rows 12b vertically provided at equal intervals between the through-holes 12 of the through-hole row 12a are provided alternately over the entire circumference of the side wall portion 11.

However, the shape of the through hole 12 does not need to be limited to a circular shape. For example, it may be polygonal,
Alternatively, it may be formed in a slit shape. It suffices if the aperture ratio is formed so as to be uniform over the entire circumference.

In the present embodiment, the upper end portion 10a and the lower end portion 10b of the cylindrical body 10 are formed to be slightly thicker than the side wall 11 provided with the through hole 12 in the present embodiment. By forming the upper and lower ends to be thick, the rigidity of the cylindrical body 10 is maintained when the cylindrical body 10 is driven.

As shown in FIG. 3, the upper end portion 10a of the cylindrical body 10 is formed integrally with the periphery of the opening end face as it is,
A narrow edge 13 is provided on the periphery thereof, and the end surface of the cylindrical body 10 has a ring shape with a circular opening 14 provided in the center. In FIG. 3, the illustration of the through holes 12 in the side wall portion 11 is partially omitted.

A cylindrical body 10 having a narrow width and a circular edge.
The size of the circular opening 14 on the side of the end face may be set to such a size that the drilling operation can be performed using a drilling machine such as an auger or a drill for shaft excavation described later.

Further, when the cylindrical body 10 is driven, the opening end peripheral edge portion 10c of the lower end side portion 10b which is the driving front end side is formed in a tapered shape so as to become thinner toward the front end. Since it is formed in a tapered shape toward the tip, that is, in the shape of a thin blade, it is easy to stand the cylinder 10 vertically on the ground surface when driving the cylinder 10, and furthermore, the cylinder 10 is Easy to do. The cylinder 10 can be driven in the vertical direction without being driven obliquely into the ground.

A lid member 20 is attached to the upper end portion 10a of the cylindrical body 10 according to the present embodiment. As shown in FIG. 4, the lid member 20 is
0 is formed in a shape conforming to the circular shape of the end face, and on the back side, a circular convex portion 21 is provided which is large enough to fit into the circular opening 14 opened on the end face side of the cylindrical body 10.

By fitting the circular projection 21 into the circular opening 14 on the end face side of the cylindrical body 10, the lid member 20 can be easily attached to the opening side of the cylindrical body 10. Further, when fitting the circular convex portion 21 into the circular opening portion 14, the circular convex portion 21 is fitted so as to ensure a sealing property so that water leakage does not occur.

For example, in order to ensure the sealing performance, a thin packing is provided at the peripheral edge of the circular opening 14 to prevent water from leaking from the gap between the circular projection 21 and the circular opening 14. It does not matter.

At the center of the lid member 20, there is provided a through-hole portion 22 penetrating the lid member 20 in the vertical direction. 23
Is protruding.

On the other hand, the container 30 used in the present embodiment
Is such that the cross-sectional area a is constant, as shown in FIG.
A buret 30a formed in a straight pipe having a constant diameter is used. Bullet 30a (30) of the present embodiment
Is formed in a transparent container having a scale on the peripheral surface so that the liquid level of the water put in the burette 30a can be read.

Further, a short tubular pipe mounting port 31 communicated with the inside of the burette 30a protrudes from the center of the bottom of the buret 30a. The pipe mounting port 23 of the cover member 20 and the pipe mounting port 31 of the burette 30a are connected to the pipe 4
0, the inside of the cylinder 10 and the burette 3
0a can be communicated with.

As the tube 40, a tube made of a suitable material such as a rubber tube or a vinyl tube may be used.

In the present embodiment, the burette 30
As shown in FIG. 1, as shown in FIG. 1, the burette 30 a can be held upright in the vertical direction with respect to the measurement ground surface with the clamp 50 sandwiching the side surface of the burette 30 a using the stand 50. I have.

In the present embodiment, the burette 30a is
Although it is formed in a straight tube without a stopcock, it may be formed in a straight tube provided with a stopcock.

Further, as shown in FIG.
A cock 32 and a water storage tank 33 are provided in a to prevent the outflow of water from occurring when the outer peripheral ground to be described later is saturated, or such that it is not necessary to inject water into the burette 30a each time. I do not care.

(Embodiment 2) In this embodiment, a method of conducting a water permeability test on the ground at the site using the water permeability test apparatus having the configuration described in the first embodiment will be described.

As shown in FIG. 6, the cylindrical body 10 is driven into a flat investigation point on the embankment ground G where the water permeability in the horizontal direction is to be inspected. When driving the cylindrical body 10, the side wall 1 having the through holes 12 is provided without the lid member 20 attached.
1 is driven in the vertical direction until the upper end 11a is below the ground surface S.

Further, in the present embodiment, the cylindrical body 10 is driven into a depth such that a part of the upper end side portion 10a of the cylindrical body 10 remains above the ground surface S.

In the state where the cylindrical body 10 is driven into the ground G in this way, a hole such as a drill or an auger is formed through the circular opening 14 on the opening end surface side of the cylindrical body 10 which is protruded above the ground surface S. The machine is put in the cylinder 10 and the shaft 60 is dug in the ground in the cylinder 10.

When excavating the shaft 60, as shown in FIG. 7, excavation is performed at a central position in the cylindrical body 10 vertically downward along a central axis in a columnar shaft. In this embodiment, the side wall portion 11 of the tubular body 10 a vertical shaft 60, with a constant radius R _i
It has been drilled deeper than the height H _s.

The depth of the shaft 60 may be set so as not to be shallower than the lower end 11b of the side wall 11 provided with the through hole 12 of the cylindrical body 10. In the present embodiment, the bottom of the shaft 60 is set to be deeper than the lower end side 11 b of the side wall portion 11.

If the inner wall of the shaft 60 is likely to collapse, a filter F made of a nonwoven fabric or a fine mesh mesh material may be provided in the shaft 60 as shown in FIG. . What is necessary is just to put the filter F on the inner wall surface of the shaft 60.

When setting the filter F, as shown in FIG. 7, the gravel A is put into the shaft 60 so as to prevent the filter F from peeling off, and the filter F on the inner wall surface of the shaft 60 is pressed with the gravel A. What should I do?

In order to prevent the filter F from peeling off from the inner wall of the pit, any material other than the gravel A may be used, and it does not prevent the water filled in the pit 60 from permeating toward the outer peripheral ground G1 around the pit 60. Such a thing may be used.

Thereafter, as shown in FIG. 8, a moat 70 is excavated by digging the outer periphery of the side wall 11 provided with the through hole 12 of the cylindrical body 10. In the present embodiment, when excavating the moat 70, the excavation was performed so as to be substantially constant concentric from the center of the shaft 60 of the cylindrical body 10.

When excavating the moat 70, the excavation is performed such that the side wall 11 of the cylindrical body 10 that has been driven into the ground is completely exposed. In this state, all the through holes 12 provided in the side wall portion 11 are completely opened toward the inside of the moat 70.

In the present embodiment, the shaft 60 extends over the entire peripheral surface of the side wall 11 provided with the through hole 12 in the moat 70.
Similarly to the inside, a filter F using a nonwoven fabric or the like is provided. Furthermore, the gravel A is put in the moat 70 to prevent the filter F from peeling off.

Further, in the present embodiment, at the time of excavation of the moat 70, a part of the ground G at the outer peripheral portion of the moat 70 is cut slightly lower than the ground surface S to form the overflow portion 71. This is because, by forming a portion lower than the ground surface S and providing the overflow portion 71, when the moat 70 is filled with water, the water level in the moat 70 always overflows even when water enters the moat 70. This is because a constant water level can be maintained in accordance with the conditions. As will be described later, since the water level of the moat 70 is a measurement standard of the head difference,
It needs to be kept constant. In order to keep the water level of the moat 70 constant, a constant water level water supply device such as a Marriott pipe may be used.

In this way, the shaft 60 is excavated inside the cylinder 10 driven into the ground G, and the side wall 1 of the cylinder 10 is excavated.
In a state in which the moat 70 is formed around the outer periphery of 1, as shown in FIG. 9, the straight tubular burette 30 a (30) is set up on the side of the cylindrical body 10. When the buret 30a is set up, the burette 30a may be set up with the clamp 51 of the stand 50 sandwiching the side surface of the buret 30a. The straight tubular burette 30a needs to be set upright so that the head can be read without error.

Further, one end of a rubber tube 40a is attached to the tube attachment port 31 on the bottom side of the burette 30a. The other end of the rubber tube 40a may be pinched and stopped by a pinch cock (not shown) or the like.

On the other hand, in this state, water is poured into the moat 70 of the cylindrical body 10. The water is supplied until it overflows into the moat 70, and once overflows through the overflow unit 71, and the water level in the moat 70 is kept constant.

Next, water is injected into the shaft 60 from the circular opening 14 of the cylindrical body 10. At the time of water injection, it is advisable to insert air until the water once overflows from the circular opening 14 of the cylindrical body 10 to release air from the cylindrical body 10.

In this state, the circular projection 21 of the lid member 20 is
Is fitted into a circular opening 14 surrounded by a border 13 on the peripheral edge of the opening end surface side of the cylindrical body 10. The attachment of the lid member 20 prevents water from overflowing from the opening end side of the cylindrical body 10 when measuring the water permeability.

The cylindrical body 10 set in this way is communicated with the burette 30 a so that water can flow from the burette 30 a into the shaft 60 inside the cylindrical body 10.

In this embodiment, when the cylindrical body 10 and the burette 30a are communicated with each other, first, the burette 30a is filled with water while the distal end side of the rubber tube 40a is sandwiched by the pinch cock as described above. Put in.

Thereafter, the pinch cock is opened, water is passed through the rubber tube 40a, and the air in the rubber tube 40a is evacuated. In this state, the rubber tube 40a is fitted to the tube mounting opening 23 of the lid member 20 by fitting the distal end side of the rubber tube 40a. In this manner, by opening the pinch cock, it is preferable that water can flow at any time from the burette 30a into the shaft 60 excavated on the ground inside the cylindrical body 10.

When the preparation is completed in this state, as shown in FIG. 10, the pinch cock is opened, and water is poured into the cylinder 10 from the inside of the burette 30a through the rubber tube 40a. In this way, the water is kept flowing in this manner for a sufficient time, and waits until the outer peripheral ground G1 surrounding the shaft 60 in the cylindrical body 10 becomes saturated.

The water that has flowed into the cylinder 10 from the burette 30 a enters the shaft 60, and further permeates from the periphery of the shaft 60 into the outer peripheral ground G 1 surrounding the shaft 60. At the time of permeation, as shown by the arrow in FIG. 11, water permeates in the horizontal direction radially in all directions from inside the shaft 60. The water that has penetrated the outer peripheral ground G <b> 1 further flows into the moat 70 from the through hole 12 penetrated in the side wall 11 of the cylindrical body 10 in the horizontal direction. By leaving it in this state for a while,
The outer ground G1 can be saturated with water from inside the shaft 60.

To determine whether or not the outer peripheral ground G1 has reached a saturated state, a change in the water head for a certain period of time is read from the burette 30a, and this is performed several times, and the outer peripheral ground is saturated with the amount of change being constant. It should be determined that.

When it is determined that the saturation has been reached, the measurement is started. Using a clock or stopwatch, etc.
Observe the change in the head of the burette 30a. In the present embodiment, as shown in FIG. 12, the head from the water level of the moat 70 of the burette 30a at the start of measurement (t = t ₁ ) is H ₁ .

Further, at the end of the measurement after the elapse of a certain time (t
= T ₂ ), the head from the water level of the moat 70 of the burette 30a is H ₂ .

In this way, the fixed time (t ₂ -t ₁ )
The change from water head H ₁ of the inner to the H _2, by reading from a burette 30a, it is possible to determine the permeability coefficient k indicating the permeability in the horizontal direction in the ground by calculation below.

In the present embodiment, as described in the first embodiment, the inner diameter of the cylindrical body 10 is set to R ₀ (same as the outer diameter of the measurement sample) and the inner diameter of the R _i , the height of the side wall portion 11 having the through hole 12 is H _s , and the sectional area of the burette is a.

Although R ₀ and H _S originally indicate the outer diameter and height of the sample to be measured, in the present invention, the cylinder 10 is driven into the ground, Since the ground portion included in the inside is used as the measurement sample, the inner diameter of the cylindrical body 10 and the outer diameter of the measurement sample can be regarded as equal.

The water permeability in the horizontal direction is determined by the side wall 1 provided with a through hole 12 for allowing water to permeate in the horizontal direction of the cylindrical body 10.
Since 1 can be regarded as the side surface of the measurement sample, H _S may be the height of the measurement sample.

From these setting conditions and the above measurement results, the horizontal permeability k can be obtained by the following equation.

K = (2.303) ² · a · log ₁₀ (R ₀ / R ₁ ) · log
₁₀ (H ₁ / H ₂ ) / 4 · π · Hs · (t ₂ −t ₁ ) The invention made by the inventor has been specifically described based on the embodiment. It is needless to say that the present invention is not limited to this, and various changes can be made without departing from the gist thereof.

For example, in the above embodiment, the cylindrical body 10 is formed into a cylindrical shape having a predetermined diameter. However, the cylindrical body is formed into a hexagonal shape, an octagonal shape, or a polygonal cross-sectional shape, and the through hole 12 is formed in the side wall portion. It may be provided. At the same time, the permeability k may be changed so that the portion related to the circular area in the above equation is related to the polygonal area.

In the above description, the invention made mainly by the inventor has been applied to the permeability test in the ground, which is the field of application, but the invention is not limited to the horizontal direction of liquid such as water of a substance other than soil. It may be applied to the liquid permeability test.

[0078]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). In the water permeability test device of the present invention, or in the water permeability test method, a moat is provided around an outer peripheral portion provided with a through hole of a cylindrical body driven into the ground, and a vertical shaft is provided in a central portion of the cylindrical body, Injecting water into the shaft and directing water from the shaft to the outer ground, it is possible to radially discharge water in all circumferential directions, so that it is possible to examine horizontal water permeability in all directions around the shaft. it can.

(2). ADVANTAGE OF THE INVENTION According to this invention, the direction parallel to the compaction surface of the embankment of an embankment, such as a fill dam and an earth dam, compacted for the purpose of water storage, ie, the horizontal water permeability, can be calculated | required.

(3). According to the present invention, the on-site permeability test can easily determine the horizontal permeability of the embankment created by compaction, which could not be obtained conventionally, so that the permeability of the fill dam or the earth dam during the construction of the earth dam can be easily obtained. Can be managed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state where a water permeability test apparatus of the present invention is installed.

FIG. 2 is a side view of the tubular body of the present embodiment.

FIG. 3 is a perspective view of a cylindrical body of the present embodiment.

FIG. 4A is a side sectional view of a lid member according to the present embodiment. (B) is a perspective view of the lid member shown in (a).

FIG. 5 is a side view showing a modified example of the configuration of the burette.

FIG. 6 is a cross-sectional view showing a state where a cylindrical body is driven into the ground in a procedure showing the water permeability test method of the present embodiment.

FIG. 7 is a cross-sectional view showing a state in which a shaft is excavated in the ground inside the cylinder in the procedure showing the permeability test method of the present embodiment.

FIG. 8 is a cross-sectional view showing a condition in which a moat is formed around the outer periphery of a side wall portion having a through hole of a cylindrical body in a procedure showing a water permeability test method of the present embodiment.

FIG. 9 is a cross-sectional view showing a state in which a cylinder and a burette are set in the procedure showing the water permeability test method of the present embodiment.

FIG. 10 is a cross-sectional view showing a state in which water is poured into each of the cylindrical body, the burette, and the moat in the procedure showing the water permeability test method of the present embodiment to saturate the outer ground surrounding the shaft.

FIG. 11 is a plan sectional view showing a flow of water from the inside of the shaft to the outer ground when the outer ground surrounding the shaft is saturated, in the procedure showing the permeability test method of the present embodiment.

FIG. 12 is a cross-sectional view showing a state in which a change in the water head is read in the procedure showing the water permeability test method according to the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Cylindrical body 10a Upper end part 10b Lower end part 10c Open end peripheral edge part 11 Side wall part 12 Through hole 12a Through hole row 12b Through hole row 13 Edge 14 Circular opening 20 Cover member 21 Circular convex part 22 Through hole 23 Pipe mounting Mouth 30 Container 30a Burette 31 Pipe attachment port 32 Cock 33 Water tank 40 Pipe 40a Rubber pipe 50 Stand 51 Clamp 60 Vertical shaft 70 Moat A Gravel F Filter G Ground G1 Outer ground S Ground surface R ₀ Inner diameter of cylinder ) R _i Inner shaft diameter H _s Height of side wall with through hole (height of measurement sample) H ₁ head H ₂ head t ₁ Start of measurement t ₂ End of measurement

Claims (5)

[Claims] 1. A water permeability test apparatus for testing the water permeability of a site ground in a horizontal direction, comprising: a container whose internal liquid height can be determined; and a side wall portion driven below the ground surface, having a through hole. A cylindrical body that can be driven into the ground in the vertical direction, a cover member provided on an opening side that is higher than the ground surface of the cylindrical body at the time of driving, and a cylindrical body that is higher than the ground surface of the cylindrical body at the time of driving And a communication means for communicating the inside of the container with the inside of the container. 2. The water permeability test apparatus according to claim 1, wherein the lid member is detachably provided on the opening side of the cylindrical body, and the communication means is a through hole provided in the lid member. A permeation test device, which is a communicating means for communicating the part with the inside of the container by a pipe. 3. The water permeability test apparatus according to claim 1, wherein the peripheral edge of the open end, which is the driving end side of the cylindrical body into the ground,
A water permeability test device characterized by being formed in a tapered shape. 4. A water permeability test method for testing the water permeability of a site ground in a horizontal direction, wherein a side wall having a through hole is provided below a surface of a measurement ground. As described above, while excavating the outer periphery of the side wall portion having the through hole of the cylindrical body to form a moat, and excavating a vertical shaft at a central position in the ground inside the cylindrical body, Water is poured until the side wall portion having the through hole is at least submerged, and the water level in the moat is kept constant. Is saturated with water from the inside of the shaft, and a water permeability coefficient is obtained from a water permeability from the inside of the shaft to the outside ground after saturation of the outside ground. 5. A permeability test method of claim 4, thereby forming the cylindrical body into a cylindrical shape having an inner diameter R _0, set the side wall having the through hole to the height H _s, wherein to form a measuring vessel straight tube cross-sectional area a, drilling the vertical shaft a cylindrical straight pit radius R _i, the measuring vessel at the measurement start time t ₁ of water permeability after saturation of the peripheral ground the water head from the Horiuchi level with the H ₁ of, when the water head from the Horiuchi water level in the measuring vessel at the measurement end time t ₂ was set to H _2, the permeability k, k = (2.303 ) ²・ a ・ log ₁₀ (R ₀ / R ₁ ) ・ log ₁₀ (H ₁ / H ₂ ) / 4 ・ π
A permeability test method characterized by being determined from the formula: Hs · (t ₂ −t ₁ ).