JP3234982B2 - Double pipe type permeation test method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents ground collapse of a test section and makes it possible to measure the permeability of groundwater while maintaining the entire range of a specified test section. However, the present invention relates to a double-pipe in-situ permeation test method and apparatus capable of performing measurement for starting permeation from a test section position and easily collecting accurate data.

[0002]

2. Description of the Related Art When constructing an underground structure or burying a water supply / drainage pipe, it is necessary to grasp the condition of groundwater and take measures to prevent trouble. Usually, an on-site permeability test is employed as a method of investigating the condition of this groundwater. In the conventional on-site permeability test method, when a test section is set on a predetermined ground, first, as shown in FIGS. A protective tube 52 is inserted and driven to the upper end of the test section. After the installation of the protective tube 52 is completed, the test section 5
Perform a 0 bowling. Then, after the boring hole 53 of the test section is drilled, the measurement sensor 55 measures the time when the groundwater 54 seeps into the boring hole 53 and rises in the protection pipe 52 above. It has become.

[0003]

However, such a conventional on-site permeability test method has the following problems. 1. The protective film made of bentonite liquid used to prevent collapse of the pore wall used during the boring of the test section must be removed by washing in order to perform an accurate water permeability test. It was difficult to maintain a normal test section. The longer the test section, the more difficult it is to deal with. 2. By measuring in an abnormal test section, only measured values far from the actual condition of the ground can be obtained. 3. If the water level 57 in the protective tube 52 rises before the water permeability test is performed, the water level is lowered using a pump, a baler 58 (see FIG. 5B), and the like. If the coefficient is large, the water level rises in a short time even if the water level is lowered, and it is very difficult to make the measurement possible in a very short time, such as inserting the measurement sensor 55 after raising the water absorption hose or the baler 58. The greater the depth of the test section, the more difficult it is to deal with it. 4. When the water level rises and the water level is lowered by pumping or the like, the boiling phenomenon causes the protection tube 5
The earth and sand may flow into the inside 2, and the removal thereof is very troublesome. If the measurement is performed without sufficient removal, only inaccurate measured values can be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to prevent a collapse of a test section and maintain a designated entire test section. Groundwater permeability measurement is possible in the condition, and accurate measurement values can be obtained.Furthermore, it is possible to start measurement from the test section position even on the ground with high permeability coefficient, and accurate data can be easily collected. It is an object of the present invention to provide a double pipe type on-site permeability test method and apparatus.

[0005]

According to a first aspect of the present invention, there is provided a double-pipe in-situ permeation test method for protecting a ground to a depth immediately before a designated test section on the ground. A method of measuring the water permeability at a designated position in the ground by boring a pipe and then boring the test section and measuring the water level of the groundwater permeating from within the test section after boring. A cylindrical water level riser for disposing a strainer pipe having substantially the same size as the length and the diameter of the borehole in the test section and communicating with the upper end of the strainer pipe to introduce groundwater permeating into the strainer pipe. Is disposed in the protection pipe, the gap between the lower edge of the water level rising path and the inner circumference of the protection pipe is sealed, and a piston is slidably inserted from the upper end of the water level rising path. Pushing down the raised groundwater to approximately the upper end position of the test section, disposing a permeability measurement sensor inside the cylindrical water level rising path above the piston-like body that pushed down the groundwater, and opening a valve provided on the piston-like body. The state in which the groundwater re-rises on the water level rising path is measured by the permeability measuring sensor.

The double pipe type on-site permeability test apparatus according to claim 2 is an apparatus used for the double pipe type on-site permeability test method according to claim 1, wherein the length of the test section and the boring are set. A strainer tube having substantially the same size as the diameter of the hole and disposed in the test section; and a cylindrical tube formed in the protective tube by being disposed in the protective tube with the upper end of the strainer tube communicating with one end. A cylindrical pipe forming a water-level rising channel, and a packer mounted on the outer peripheral side of the lower end of the cylindrical pipe and sealing a gap formed between the outer circumference of the cylindrical pipe inserted into the protective pipe and the inner circumference of the protective pipe. A valve body having an outer peripheral surface slidably in close contact with a water level rising path formed by the cylindrical pipe, and a valve body for vertically opening and closing a flow passage provided in the valve body to be opened and closed by operating means from the ground side. Yes, A piston-type valve inserted from above the cylindrical pipe in a state where the vertical through-flow channel is closed by the valve body and pushing down the raised groundwater to a substantially upper end position of the test section; and And a permeability measurement sensor disposed in a water level rising path above the piston type valve that has pressed down.

According to a third aspect of the present invention, there is provided a double pipe type on-site water permeability test apparatus according to the second aspect, wherein the valve body is provided in a vertical through flow path of the valve body. It is formed in a tapered plug shape that is detachably fitted from the upper side, and a rope for tripping from the vertical passage is connected to the upper surface, and a piston rod that presses the upper surface of the valve body from the ground side is detachable. It is characterized by being prepared for.

According to a fourth aspect of the present invention, there is provided a double pipe type on-site water permeability test apparatus according to the second or third aspect, wherein the valve body has an inner diameter of the cylindrical pipe. On the other hand, from a pair of cylindrical members having a small outer diameter capable of forming a gap and having a male screw or a female screw at an end, and a soft ring material which expands the outer diameter to be larger than the inner diameter of the cylindrical pipe by compressing both end faces. By inserting one end of the cylindrical member from both ends of the ring material and screwing the screw portions together, the ring material is integrated by pressing the ring material at the step provided at the end of the screw portion. It is characterized by the following.

According to a fifth aspect of the present invention, there is provided a double pipe type on-site water permeability test apparatus according to any one of claims 2 to 4, wherein the valve body is provided. Is a flexible rope extending to the ground side, a screw shaft having one end fixed to the tip of the rope, a pair of washers inserted into the screw shaft, and screwed to the screw shaft to adjust the washer interval. And a soft valve member that is disposed between the washers and expands and contracts the outer diameter when the nut is tightened.

According to a sixth aspect of the present invention, in the double pipe type on-site water permeability test apparatus according to any one of the second to fifth aspects, the cylindrical pipe is provided. Is characterized in that the inner peripheral surface side is formed of a resin material.

According to a seventh aspect of the present invention, in the double pipe type on-site permeability test apparatus according to any one of claims 2 to 6, the strainer pipe may be used. Is characterized in that a plurality of strainer tube members are connected to each other to be extendable.

[0012]

According to the double pipe type on-site permeability test method of the first aspect and the double pipe type on-site permeability test apparatus of the second aspect,
A strainer tube is connected to the tip of the cylindrical tube.
When the test section is bored, insert the strainer tube first into the protective tube. The strainer tube is arranged in a fitting state in the borehole, which is the test section, and the cylindrical tube is arranged in the protective tube. In this state, the cylindrical tube forms a cylindrical water level rising path above the strainer tube in the protective tube. You do it. The borehole does not collapse due to the presence of the strainer tube and remains in its original shape. When the piston type valve is inserted into the cylindrical pipe and pushed to the upper end of the test section, the groundwater that has entered the inside of the water level ascending path through the strainer pipe can be discharged around the test section through the strainer pipe. By opening the valve body from the ground side and opening the vertical through flow path of the valve body, the groundwater re-enters the rising water channel and rises to the water level at the test section position. By measuring with a measurement sensor, the characteristics of groundwater at that depth can be known. In other words, according to the first and second aspects of the present invention, it is possible to prevent the collapse of the test section and measure the permeability of the groundwater while maintaining the entire range of the specified test section, and obtain a highly accurate measurement value. In addition, even when the ground has a high permeability, it is possible to measure the start of the permeability from the test section position, so that accurate data can be easily collected. In addition, the recovery method for measuring the rising water level of groundwater and the injection method for measuring the falling water level by supplying water can be performed with high accuracy.

[0013] In the double pipe type on-site water permeability test apparatus according to the third aspect, the piston type valve is provided with a simple valve which can be plugged from the upper side of the vertical passage, that is, from the pushing side. It is. By inserting this piston type valve into the water level rising path, hitting the piston rod against the valve body and pressing it down, the valve body can be easily pressed down the groundwater integrally with the valve body without opening by water pressure it can. The valve body can be pulled out from the ground side using a tripping rope, and the upper and lower through passages can be easily opened.

According to a fourth aspect of the present invention, the valve body slides in a state where a soft ring material provided at an intermediate portion is in contact with the inside of the cylindrical pipe. Since this ring material changes the outer diameter in the screwing state of both cylindrical members, it can be adjusted to the best condition for the inner diameter of the cylindrical pipe used,
Efficient work can be performed.

In the double pipe type permeation test apparatus according to the fifth aspect, the valve body is lowered by lowering the valve body when the groundwater is pushed in, and the valve body is stopped by pulling up the rope when the vertical passage is opened to open the valve. The valve material is adjusted so as to obtain the best contact state with the vertical passage of the valve body by tightening the nut so that only the main body can be lightly separated.

In the double pipe type on-site water permeability test apparatus according to the sixth aspect, since the inner peripheral surface of the cylindrical pipe is formed of resin, the work can be carried out easily without rusting at all times.

In the double pipe type on-site water permeability test apparatus according to the present invention, it is possible to easily correspond to various lengths of the test section and to always perform accurate measurement anywhere.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a state in which the water level of a double-pipe on-site permeability test apparatus according to the present embodiment is lowered, and FIG.
FIG. 4 is an explanatory diagram showing a state in which the rising water level is measured. First, the double pipe type on-site water permeability test apparatus A has a main configuration including a cylindrical pipe 1, a packer 2, a piston type valve 3, a piston rod 4, a strainer pipe 5, and a measurement sensor 6. . In the figure, 7 is a protective tube, 8 is a test section, and the protective tube 7 is cast to the upper end of the test section 8 set on the ground 9 at a predetermined depth.

The cylindrical pipe 1 is disposed in the protective pipe 7 so that the cylindrical water level rising path 1
0, a steel pipe 11 having a diameter smaller than that of the protective tube 7 is used, and an extension screw portion (not shown) is screwed at the end so as to be able to cope with a deep depth of the test section 8. Have been. The inner peripheral surface of the cylindrical tube 1 is formed of a resin coating 12 so that a piston valve 3 described later slides favorably.

The packer 2 seals a gap 13 formed between the outer periphery of the cylindrical tube 1 inserted into the protective tube 7 and the inner periphery of the protective tube 7. It is mounted on the outer peripheral side of the lower end of the tube 1. A hose 14 connects the packer 2 to a ground-side air pressure source.

The piston type valve 3 pushes down the groundwater 15 raised in the water level rising channel 10 to a substantially upper end position of the test section 8 and opens it at the start of measurement.
A valve body 16 having an outer peripheral surface slidably adhered to the water level rising path 10 formed by the cylindrical pipe 1 and the valve body 16
The upper and lower through-passage channels 18 provided in the above are configured to be opened and closed by operating means from the ground side. As shown in FIG. 3A, the valve main body 17 includes a flexible rope 20 extending to the ground side as operation means from the ground side, and a screw shaft 21 having one end fixed to the tip of the rope 20. And a pair of washers 22, 22 inserted into the screw shaft 21, a nut 23 screwed to the screw shaft 21 to adjust the interval between the washers 22, 22, and between the washers 22, 22. It is formed of a soft (for example, rubber, a flexible resin material, or a mixture thereof) valve material 24 which is arranged and expands and contracts the outer diameter when the nut 23 is tightened. Although the valve member 24 is shown with a tapered outer shape, the valve member 24 does not necessarily have to have a tapered shape, and may have a cylindrical or drum-shaped outer shape.

The valve body 16 has a small outer diameter capable of forming a gap with respect to the inner diameter of the cylindrical tube 1 and has a pair of cylindrical members 2 having a male screw 25 or a female screw 26 at an end.
7 and 28, and a soft (for example, similar to the valve member 24) ring member 29 whose outer diameter is larger than the inner diameter of the cylindrical tube 1 by compressing both end surfaces. The cylindrical members 27 and 28 respectively
Of the ring member 2 by screwing the threaded portions 25 and 26 together by inserting one end of the ring material 2 into the stepped portion 30 provided at the end of the threaded portion.
9 is pressed and integrated.

The piston rod 4 is used by abutting against the upper surface of a valve body 17 when pushing down the groundwater 15 raised in the water level rising path 10 to a substantially upper end position of the test section 8 by the piston type valve 3. A small-diameter steel pipe is used, and a cut-out portion 31 is formed at the end abutting portion so as not to interfere with the rope 20.

The strainer tube 5 prevents the test section 8 from collapsing at the time of removing or measuring the bentonite protective film, boiling, and the like. And a net 33 is provided to prevent earth and sand from entering therefrom,
The length of the test section 8 and the diameter of the bore hole 34 are substantially the same. Further, this strainer tube 5 can easily correspond to various lengths of the test section and always connect a plurality of strainer tube members, for example, to a maximum length of 2.5 m so that accurate measurement can be performed anywhere. It is formed to be extendable.

The measurement sensor 6 is attached to the end of a long cable 35 so that measurement can be performed immediately above the test section 8, and is provided so that it can be set or removed independently.

Next, the operation of the present embodiment will be described. In the double pipe type on-site water permeability test apparatus A configured as described above, first, when the protective tube 7 is cast and the test section 8 is drilled by boring, the strainer tube 5 is inserted into the protective tube 7 first. . The strainer tube 5 is disposed in the test section (boring hole) 8 in a fitted state, and the cylindrical tube 1 is disposed in the protective tube 7. A cylindrical water level rising path 10 is formed at the upper part. Thereafter, a pump or a hose of the pump is inserted from the upper end of the cylindrical pipe 1 to the strainer pipe to discharge the muddy water therein. Or, after supplying fresh water, drain by suction. At this time,
The boring hole 8 is in a state in which the bentonite protective film is removed while maintaining the original shape without collapse due to the presence of the strainer tube 5. After the muddy water is discharged, air is injected into the packer 2 from the ground to increase the water level rising path 10, that is, the cylindrical pipe 1.
The gap formed between the test tube 8 and the protection tube 7 is sealed, and the space that connects the test section 8 and the ground is only inside the water level rising channel 10. The measurement will now be described. First, the recovery method will be described. When the piston type valve 3 is inserted from the upper end of the water rising channel 10 and pushed into the upper end of the test section 8 with the piston rod 4, the groundwater 15 that has entered the inside of the water rising channel 10 through the strainer pipe 5 is reversed. It is discharged around the test section 8 through the strainer tube 5. After pushing the piston type valve 3 to the upper end of the test section 8, the measurement sensor 6 is inserted to the upper part of the piston type valve 3, the rope 20 is pulled up from the ground side 19, the valve body 17 is opened, and the valve body 16 is opened. Vertical penetration channel 18
To release. With the opening of the vertical through flow channel 18, the groundwater 15 again enters the water level rising channel 10 and rises to the water level at the position of the test section. By the recovery method of measuring the rise in the water level by the measurement sensor 6, the characteristics of the groundwater at that depth can be known.

Next, the injection method is performed after the completion of the recovery method.
In this case, the valve body 17 remaining on the water level rising path 10 is removed with a keyed rod or the like. Then, as shown in FIG. 4, fresh water 36 is injected from the upper end of the water level rising path 10, and the pressure in the unit of time due to the drop of the water level 37 is measured by the measurement sensor 6, thereby completely maintaining the specified test interval. The result obtained with high accuracy is obtained.

Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to this embodiment. For example, the shapes of the piston type valve 3 and the strainer tube 5 can be arbitrarily set.

[0029]

As described above, the double pipe type on-site water permeability test method and apparatus according to the present invention has the above-described method and configuration, so that the test section is prevented from collapsing and the entire test section is designated. Measurement of groundwater permeability is possible while holding the groundwater, and accurate measurement values can be obtained.Furthermore, it is possible to start measurement from the test section position even on the ground with a high permeability coefficient, making accurate data easy. Can be collected. Both the recovery method, which measures the rising water level of groundwater, and the injection method, which measures the falling water level by supplying water, can perform accurate measurements in a short time.

The piston type valve is inserted into the water level rising path, and the piston rod is pressed against the valve main body and pressed downward, so that the valve main body is integrated with the valve body without being opened by water pressure and easily pushes down groundwater. be able to. The valve body can be pulled out from the ground side using a tripping rope, and the upper and lower through passages can be easily opened.

The valve body slides in a state where a soft ring material provided at an intermediate portion is in contact with the inside of the cylindrical tube. However, since the outer diameter of the ring material changes when the two cylindrical members are screwed, the cylindrical body used is not used. It can be adjusted to the best condition for the inner diameter of the pipe, and efficient work can be performed.

When the valve body is lowered, the valve body is lowered when the groundwater is pushed in, and the valve body is stopped by pulling up the rope when opening the vertical passage, so that only the valve body can be lightly detached. Adjustment can be made to obtain the best contact state with the upper and lower through passages of the main body.

Since the inner peripheral surface of the cylindrical tube is formed of a resin, there is no rust and the work can always be carried out easily.

The strainer tube can easily cope with various lengths of the test section, and has an effect that an accurate measurement can be always performed anywhere.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state in which the water level of a double-pipe on-site permeability test apparatus A according to an embodiment of the present invention is lowered.

FIG. 2 is an explanatory diagram showing a state in which a rising water level of a double-pipe on-site permeability test apparatus A of the embodiment is being measured.

FIG. 3 shows a piston type valve according to the embodiment;
(A) is a sectional view showing a valve body, and (B) is a sectional view showing a valve body.

FIG. 4 is an explanatory view showing a water injection method of the double pipe type on-site water permeability test apparatus A of the embodiment.

FIGS. 5A and 5B are explanatory views showing a conventional on-site permeability test method.

[Explanation of symbols]

 A Double pipe type on-site water permeability test apparatus 1 Cylindrical pipe 2 Packer 3 Piston valve 4 Piston rod 5 Strainer pipe 6 Measurement sensor 7 Protective pipe 8 Test section 10 Water level rising path 12 Resin coating in cylindrical pipe 13 Gap 16 Valve body 17 Valve body 18 Vertical through flow path 20 Rope 24 Valve material 29 Ring material

Claims (7)

(57) [Claims] Claims: 1. A test tube is drilled to a depth immediately before a designated test section in a ground, and then the test section is bored. After boring, the level of groundwater permeating from the test section is measured. A method for measuring the permeability at a specified position on the ground, comprising: disposing a strainer pipe having substantially the same size as the length of the test section and the diameter of the borehole in the test section and communicating with the upper end of the strainer pipe. And disposing a cylindrical water level rising channel for introducing groundwater permeating into the strainer pipe in the protection tube, sealing a gap between a lower periphery of the water level rising channel and an inner circumference of the protection tube, and A piston-like body is slidably inserted from the end to push down the raised groundwater to substantially the upper end position of the test section, and on the piston-like body that has pushed down the groundwater A permeation measurement sensor is arranged inside the cylindrical water level rising path, and a state in which the groundwater rises again in the water level rising path by opening a valve provided in the piston-like body is measured by the permeation measurement sensor. Double pipe type permeation test method. 2. The apparatus used in the double pipe type permeation test method according to claim 1, wherein the test section has a length substantially equal to a length of the test section and a diameter of a boring hole. A strainer pipe to be disposed; a cylindrical pipe which forms a cylindrical water level rising path in the protective pipe by being disposed in the protective pipe with an upper end of the strainer pipe communicating with one end; and a lower end of the cylindrical pipe A packer for sealing a gap formed between the outer periphery of the cylindrical tube and the inner periphery of the protective tube attached to the outer peripheral side and inserted into the protective tube; and an outer peripheral surface slidable on a water level rising path by the cylindrical tube. The valve body includes a valve body that adheres and a valve body that vertically closes the flow path provided in the valve body so as to be opened and closed by operating means from the ground side. The valve body closes the vertical flow path. A piston-type valve inserted from above the cylindrical pipe to push down the raised groundwater to a substantially upper end position of the test section; and a piston-type valve inside the water-level riser and disposed in a water-level riser above the piston-type valve that has pushed down the groundwater. A double pipe type on-site permeation test apparatus, comprising: 3. The double-pipe in-situ water permeability test apparatus according to claim 2, wherein the valve body is formed in a tapered plug shape that is detachably fitted to an upper and lower through flow path of the valve body from above. And a rope for tripping from the vertical passage is connected to the upper surface, and a piston rod for pressing the upper surface of the valve body from the ground side is detachably provided. apparatus. 4. The double pipe type in-situ water permeability test apparatus according to claim 2, wherein the valve body has a small outer diameter capable of forming a gap with respect to the inner diameter of the cylindrical pipe, and has a male screw at an end. Or a pair of cylindrical members having female threads, and a soft ring material whose outer diameter is expanded to be larger than the inner diameter of the cylindrical pipe by compressing both end faces, and one end of each of the cylindrical members is inserted from both ends of the ring material. A double-pipe type on-site water permeability test apparatus, wherein the ring portions are screwed together so that the ring material is pressed and integrated at a step provided at the end of the screw portion. 5. The double pipe type on-site permeability test apparatus according to claim 2, wherein the valve body is a flexible rope extending to the ground side.
A screw shaft having one end fixed to the tip of the rope, a pair of washers inserted into the screw shaft, a nut screwed onto the screw shaft to adjust the washer interval, and a nut disposed between the washers And a soft valve material that expands and contracts the outer diameter in a tightened state. 6. The double pipe type on-site water permeability test apparatus according to claim 2, wherein an inner peripheral surface side of the cylindrical pipe is formed of a resin material. Double pipe type permeation test equipment. 7. The double pipe type on-site permeability test apparatus according to claim 2, wherein the strainer pipe is formed so as to be extended by connecting a plurality of strainer pipe members. A double-pipe on-site water permeability test apparatus characterized by the following.