JPH01161129A - Method and device for sampling ground sample incorporating core catcher forcible pressing-in device - Google Patents

Abstract

PURPOSE:To securely sample even the sand ground by bending one end part of a core catcher toward the longitudinal center shaft of the core catcher. CONSTITUTION:The inner periphery of a sample storage tube 9 is nearly equal in diameter to the outer periphery of the core catcher 10 and a sample is put in the tube, water in the tube is discharged from a water running hole 14 through a one-wave value 13. When the sample 15 of prescribed length is put in the sample storage tube 9, a hydraulic pump and a hose are connected and water is fed reversely through the water running hole 14; and then the ball of the one-way valve 13 moves down to stop the water and a piston 12 moves down. The piston 12 presses the core catcher 10 through the sample storage tube 9 to slide the catcher on the tapered surface of a taper ring 11 which is formed by chamfering the external surface of the blade edge part of the core catcher 10 toward the blade edge, so that one saw-tooth end surface of the core catcher 10 intrudes into the sample 15 while bent inward. Consequently, even the sand ground can securely be sampled.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for collecting ground samples, and the present invention relates to a method for collecting ground samples, and in particular, to collecting unconsolidated samples such as sand and gravel below the groundwater table without dropping samples required for geotechnical engineering. The present invention relates to a method and apparatus for reliably collecting samples from underground, which could not be reliably collected using conventional techniques.

[Conventional technology]

Recently, we have been collecting undisturbed sand and gravel from underground.
It is desired to perform various tests using this test monthly rate to determine the strength constant and deformation constant. Many methods for collecting samples without disturbing them have been devised and put into practical use, but in the case of medium to hard ground, sampling devices consisting of double or triple pipes are used. This is a method in which the outer tube is rotated to cut the ground, and at the same time the inner tube is not rotated and its tip is pressed into the ground to collect a sample. A typical sample sampling device of this type is a triple tube type device, such as Utility Model Registration No. 1411322.

On the other hand, unconsolidated sand or gravel ground does not have adhesive strength, so the sample tends to fall off when the sample collection device is pulled up to the ground. For this reason, many ideas have been devised regarding methods for preventing falling off. For example, Special Publication No. 37-18545 @ Official Publication, Publication No. 54-24711, Publication No. 42960 of Utility Model No. 54-42960.
Publication No. 56-31536, Special Publication No. 57-
41687, Japanese Patent Publication No. 57-175242@, Japanese Utility Model Publication No. 62-27866, and other known facts include basket type or tapered ring type core catchers.

[Problem that the invention seeks to solve]

The most important problem when collecting samples from unconsolidated sand or gravel ground is preventing the sample from falling off.

In particular, samples below the groundwater table tend to fall off easily, and there is currently no reliable method to prevent them from falling off using conventional techniques. FIG. 1 shows an example of a core catcher (19) of the pass digit type 1 which has been commonly used in the past.

This is generally a cylindrical leaf spring with one end shaped like a saw blade (2o), bent inward to form a roughly hemispherical shape, and the blade tip is attached to the lower part of the inner tube of the collection device. By attaching the sample with the plate facing upward, if the sample tries to fall off due to the force of the leaf spring, the blade made of the plate spring will catch on the sample. This method is useful on compacted or sticky ground, but on unconsolidated ground the sample may fall out between the leaf springs.

Tapered link type core catchers are also commonly used, but these are intended for use on rocky ground and are not useful on sand or gravel ground. For soft ground, methods such as pressurizing the lower part of the sample with a rubber tube, twisting and tightening, and various shutters have been devised, but these methods are difficult to apply to medium to hard unconsolidated sand or gravel ground.

(Means for Solving the Problems) In view of this, and as a result of various inspections, the present invention has developed a ground sample collection method and device with a built-in core catcher forced injection device that can reliably collect ground samples even in sandy and gravel ground. It is something.

That is, in the method of the present invention, a porin blond is lowered to the bottom of a bore hole drilled in the ground, applying rotational force and pressure force, and is placed at the lower end of the borehole at the tip of the cylindrical outer tube. The ground sample was excavated and placed inside the outer tube (=J-C). In this method, one end of the cylindrical shape is formed into a saw blade shape and/or a plurality of strips, and the outer surface of each end is chamfered toward the tip to form a tapered surface. , a tapered surface that is in close contact with the tapered surface of the core catch provided inscribed in the inner tube between the sample storage tube and the cutting sheet 1 is formed in an annular shape, and the sample storage tube is attached to the inner surface of the inner tube. -i) MH side of the core catcher by lowering it along the line and opening the tapered surfaces of the core catcher.
It is characterized by being bent toward the central axis in the vertical direction of the acrylic V.

Furthermore, the device of the present invention fixes the upper end of a cylindrical outer tube with a bit for digging the ground at the tip to the lower end of a boring rod that applies rotational force and pressing force, and cuts the ground inside the outer tube. Boring with a cylindrical cutting shoe at the tip for obtaining a ground sample, an inner tube with a cylindrical sample storage tube inscribed in it, and an outer tube installed in such a way that the rotational force of the Pauline Blond is not transmitted, and this outer tube is drilled into the ground. In a device that descends to the bottom of a hole and collects a soil test* in a sample storage tube, one end of a cylindrical shape is formed into a saw blade shape and/or a plurality of strips, and the outer surface of each end is shaped like a saw blade. A core catcher with a tapered surface chamfered inwardly is provided inscribed in the inner tube between the sample storage tube and the cutting shoe, and a tapered surface that is in close contact with the tapered surface is formed in an annular shape to catch the sample. A sample storage tube for bending one end side of a core catcher toward the longitudinal center axis of the core catcher by lowering the storage tube along the inner surface of the inner tube and sliding the tapered surfaces of the inner tube. It is characterized by being provided with a pressurizing device, and furthermore, one end of the cylindrical plate spring is provided with its one end facing downward, and one end of the cylindrical leaf spring is provided with a serrated and/or Alternatively, a pass-scale type core catcher made of a plurality of strips with one end bent inward and formed into a substantially hemispherical shape is installed below the core catcher with one end facing upward. It is effective to use Acatch A, which has a screen with openings on the inner periphery that does not allow soil particles to pass through and is permeable to water. Particularly effective in preventing particles from falling.

[For production]

In this way, it is similar to the conventional Basquera 1 style] Acatch ■, where one end of the cylindrical shape is formed into a saw blade shape and/or a strip shape, and the outer surface of each end is chamfered toward the tip to create a tapered shape. The structure was made possible by using an acatcher (having a shape with a flat surface) and forcibly penetrating the entire cross section of the sample, rather than relying on a spring. 1) When pulling up the device -〇 -, water will be Ux (j), but at this time, to prevent soil particles from falling along with it, place between each blade or between each strip of paper. This is to prevent gaps from forming.

In addition, in order to perform this operation, the tapered surface that closely covers the blade at one end of the 1st catcher or the tapered surface where the outer surface of the end of the strip is chamfered toward the tip is usually used to connect the tapered ring to the inside of the inner tube. It is sufficient to install the core catcher in close contact with the circumference, but if you do not use a tapered ring but want to point the tip of one end of the core catcher upward, form a tapered surface on the lower end surface of the sample storage tube, and also If the tip is directed downward, a tapered surface may be formed on the upper end surface of the cutting shoe.

Furthermore, in order to make it possible to drain water from the gaps between adjacent or overlapping blades and strips of the core catcher, but to prevent soil particles from falling, the following screen is installed inside the catcher.

The screen has a cylindrical shape with an inner diameter approximately the same as that of the sample storage tube, and a wire mesh or an easily bendable perforated tube with a pitch smaller than the diameter of 10 particles can be used.

In addition, in order to ensure that the specimen does not fall off, the catchers are installed in two stages, one of which is the forcibly press-fit type core catcher described above, and the other is the conventional Baskera 1~ type core catcher that uses a spring. With this configuration, when one forcible core catcher is activated, the other basket-type core catch ψ automatically returns to its original approximately hemispherical shape, thereby blocking the cross section of the sample and making it reliable to prevent the sample from falling out. Sexuality increases.

(Example〕 Next, one embodiment of the present invention will be described.

Figure 2 shows the inside R of the core catcher forced press-in device according to the present invention.
This shows a type of ground sampling device, in which the boring rod (1) set on a ground boring machine (not shown) is connected to the sample sampling device head (2), which is not lowered to the bottom of the borehole. Pressure force and rotational force are applied to the rond (1),
Pass this through the cylindrical outer tube (3) and the bit (4) at the tip of the outer tube.
) to cut the ground. Circulating fluid is pressurized from the ground through the inside of the boring rod (page 1), jetted out from the tip of the bit (4), and discharged to the ground through the outside of the outer tube. The inner tube head (5) is connected to the sampling device head (
2) Bearing housing (6) installed inside
The inner tube head (5) is fixed to the inner tube head (5) so that no rotational force is transmitted thereto. This allows the inner tube head (5)
Pressure force from the rod is transmitted through the cylindrical inner tube (7) connected to the inner tube (7), and the sample is pushed through the ground with the cylindrical cutting shoe (8) attached to the tip of the inner tube (7). 7) is inscribed in the sample storage tube.

Furthermore, in order to prevent the taken sample from falling off, a core catcher (10 ) is installed. The one shown is when the cutting edge of the core catcher (10) is turned downward.In order to obtain a tapered surface that comes into close contact with the tapered surface of the cutting edge, there is a taper between the cutting edge and the upper end surface of the cutting shoe (8). The ring (11) is held in place.

Furthermore, in order to press fit the core catcher (10) into the sample, the lower surface of the piston (12) is fixed to the upper end of the sample storage tube (9), and a through hole is provided in the center of the piston (12) to form a one-way valve. (13) is attached.

When collecting a ground sample using such a sample collecting device, the inner circumference of the sample storage tube (9) and the core catcher (10
) have approximately the same diameter, and when the sample enters the tube, the water in the tube passes through the one-way valve (13) and is drained from the water hole (14). A water hole (14) passes through the sampling device head (2) and is connected to a hose (not shown) and led to the ground. When a sample of a predetermined length enters the sample storage tube, connect a water pressure pump (not shown) and a hose, and conversely send water through the water hole (14) until the ball of the one-way valve (13) or the bottom stop. Then, as shown in FIG. 3, the screws 1 to 12 (12) are lowered. The piston (12) pushes the core catcher (10) through the sample storage tube (9), and pushes the outer surface of the cutting edge of the core catcher (10) toward the cutting edge on the tapered surface of the tapered ring (11). By sliding the chamfered tapered surface, one end of the saw blade shape of the core catcher (10) penetrates into the sample (15) while being bent inward. Note that this press-fitting device is not limited to a hydraulic piston, but may also be a screw jack using the rotation of a Pauline blond.

Furthermore, the figure on the left side of the center line in FIG. 3 shows the state before the core catcher (10) is press-fitted, and the figure on the right side shows the state after the core catcher (10) is press-fitted. Note that several grooves (16) are provided in the inner surface of the core catcher (10) in the circumferential direction so that the blade part can easily bend when the core catcher is press-fitted.

In addition, if the arch action is likely to work effectively due to the soil particles of the collected sample coming into contact with each other, set the cutting edge of the core catcher (10) upward as shown in Figure 4, and connect the cutting edge and the sample storage tube (9). Place a taper ring between them and press screws 1 to 12 (12) in the same manner as above to attach the core catcher (10).
) is pressed into the sample (15) to collect a ground sample.

Next, if the ground is such that soil particles fall together with water from the gap in the catcher, use a wire mesh with a mesh that prevents soil particles from passing through, as shown in Figure 5, and a screen with the same inner diameter as the sample storage tube (9). (17) is attached to the inner surface of the core catcher (10). This can be done by making a hole in the catch A7 itself.It is possible to prevent the soil particles from flowing out by concentrating the water in the sample locally and dehydrating it, but to make it more reliable, it is possible to prevent the soil particles from flowing out. A bra that does that is good.

Furthermore, Fig. 6 shows that in the case of a sample that is very likely to fall, in order to more reliably prevent the sample from falling off, the structure is such that a two-stage V-type mechanism is activated, and the upper stage core catcher (
10) is the same as in Figure 3, or the lower catcher is attached near the tip of the catching shoe (8).
This is a lower kick retcher (19) of Passquera 1-type, in which one end of a conventional cylindrical leaf spring is formed into a plurality of strips (18). -15= on the left side of the figure shows the state before sample collection. On the right side of the figure, with the catcher pressed in, the sample (15) or the predetermined length is shown. When P [19) is forcibly bent inward by the blade of the upper catcher in addition to its own spring force, the sample also penetrates into the sample. (15) is even less likely to drop out.

(Effects of the Invention) As described above, according to the present invention, since one end of the core catch V forcibly penetrates into the sample taken in, remarkable effects such as being able to reliably collect samples without causing the ground sample to fall off are achieved. It is something to play.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional Basquera 1-type core catcher, Fig. 2 is a sectional view showing an embodiment of the present invention, and Fig. 3 shows the operation when the core catcher is taken downward. Fig. 4 is an explanatory drawing showing the operation when the core catch A is installed upward, Fig. 5 is a sectional view showing the screen attached to catch V, and Fig. 6 is a two-stage type. It is an explanatory diagram showing operation of a catcher. 1...Boring rod 2...Sample collecting device head 3...
...Cylindrical outer tube 4...Heat 1 to 5...Inner tube head 6...Bearing housing 7...
... Cylindrical inner tube 8 ... Cylindrical cutting shoe 9 ...
......Sample storage tube 10...]Aagi hooker 11...Taper ring 12...Screws 1 to 13...・One-way valve 14...Water hole 15...Sample 16...Groove 17...Screen 18...・・・・・・Rectangular shape 19・・・・・・Bath gear type core catch (・
20......Before serrated press-in Before Eiri rectangular press-in After press-in and before press-in Press-in

Claims (4)

[Claims] (1) A boring rod with rotational force and pressing force applied to the bottom of a borehole drilled in the ground is lowered, and the ground is excavated with the bit at the tip of the cylindrical outer pipe provided at the lower end, and the inside of the outer pipe is In this method, a ground sample obtained by cutting the ground with a cylindrical cutting shoe attached to the tip of an inner tube is taken into a cylindrical sample storage tube inscribed in the inner tube. It is formed into a saw blade shape and/or a plurality of strips, the outer surface of each end is chamfered toward the tip to form a tapered surface, and is inscribed in the inner tube between the sample storage tube and the cutting shoe. One end of the core catcher is formed by forming a tapered surface in close contact with the tapered surface of the provided core catcher into an annular shape, and by lowering the sample storage tube onto the inner surface of the inner tube and sliding the tapered surfaces together. 1. A ground sample collection method with a built-in core catcher forcible press-in device, characterized in that the sides are bent toward the longitudinal central axis of the core catcher. (2) Fix the upper end of a cylindrical outer tube with a bit for digging the ground at the tip to the lower end of a boring rod that applies rotational force and pressing force, and cut the ground inside the outer tube to sample the ground. An inner tube with a cylindrical cutting shoe at the tip and a cylindrical sample storage tube inside is attached so that the rotational force of the boring rod is not transmitted, and this outer tube is attached to the bottom of a borehole drilled into the ground. In a device that descends into a sample storage tube and collects a ground sample, one end of the cylindrical shape is formed into a saw blade shape and/or a plurality of strips, and the outer surface of each end is chamfered toward the tip. A core catcher with a tapered surface is provided inscribed in the inner tube between the sample storage tube and the cutting shoe, and a tapered surface that is in close contact with the tapered surface is formed in an annular shape so that the sample storage tube can be held inside the sample storage tube. A pressurizing device for a sample storage tube is provided for bending one end side of the core catcher toward the longitudinal center axis of the core catcher by lowering it along the inner surface of the tube and sliding the tapered surfaces together. A ground sampling device with a built-in core catcher forced-in device. (3) A core catcher is provided with one end facing downward, and one end of the cylindrical leaf spring is shaped like a saw blade and/or a plurality of strips, and the one end is bent inward to form a shape along a substantially hemispherical surface. A ground sampling device with a built-in core catcher forcible press-in device according to claim 2, wherein a basket-type core catcher is provided below the core catcher with one end thereof facing upward. (4) A core catcher forcible press-in device according to claim 2 or 3, which uses a core catcher in which a screen having openings that do not allow soil particles to pass through and is permeable to water is formed on the inner circumferential side. Built-in soil sampling device.