JPS62141294A - Frozen ground sampler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for taking ground samples, and more particularly to a frozen ground sampling device for taking samples of frozen sand and gravel ground.

BACKGROUND OF THE INVENTION Recently, there has been a demand for collecting undisturbed sand or gravel from underground and conducting various tests using it as a test sample to determine strength constants and deformation constants. Many methods for collecting samples without disturbing them have been devised and put into practical use, but the principle of sample collection devices can be roughly divided into methods that press-fit a tubular sampler for relatively soft ground, methods for press-fitting a tubular sampler for relatively soft ground, and methods for collecting samples from medium to hard ground. This is a sampler consisting of a double or triple tube, and the outer tube is rotated to cut the ground, while the inner tube is not rotated and its cutting edge is pressed into the ground to collect the sample. There are two methods: a single-tube sampler that collects samples while rotating and cutting the solid ground, and a sampler that is equipped with a tube to store the sample inside the sampler.

For relatively soft sandy ground where the diameter of soil particles is in the range of 74 microns to 211IIIll, a method of press-fitting a tubular sampler is used, but since sandy ground does not have adhesive strength, it is difficult to place the sampler on the ground. The sample easily falls off when being pulled up. Therefore, the focus has been on developing methods to prevent them from falling off.

For example, Japanese Patent Publication No. 37-18545, Publication No. 18545-
Publication No. 24711, Publication Utility Model Publication No. 54-42960, Publication No. 31536-1987, Publication No. 41687-1987
There are publications, etc.

For medium to dense relatively hard sandy ground, a triple tube sampler is used, and the utility model registered tube 1411322j
This corresponds to M, etc. It has become a well-known fact that the samples collected by these various samplers are disturbed during sample collection and transport, making it impossible to fully evaluate the characteristics of the original ground. This is due to the practice of freezing and solidifying the sandy ground before collecting it.

Unlike the case of sandy ground, collecting undisturbed samples of gravel ground where soil particles have a diameter of 2 mm or more involves cutting the soil particles, so undisturbed samples have not been collected. Recently, a method has been used to freeze soil particles and then cut and collect them while holding the soil particles strongly.

In this way, the sample collection method that uses the freezing method in combination has come to be recognized as a high-quality sample collection method with less disturbance, but the sampler is a conventional sampler that targets solidified ground such as bedrock. Currently, it is used.

Samplers for collecting undisturbed samples of frozen sand and gravel ground include two methods: a single-tube sampler (single-core barrel) that collects samples while rotating and cutting; One with a tube attached (
There is a double core barrel).

In order to collect samples by cutting frozen ground without thawing it, the circulating fluid required for cutting requires different characteristics from those for unfrozen ground. For unfrozen ground, fresh water or mixed mud water is usually used, but for frozen ground, it needs to be kept at a low temperature of 0°C or lower. In addition to such a circulating fluid pond mainly composed of water, a pond mainly composed of air may also be used.

For example, Japanese Patent Publication No. 49-6961, Japanese Patent Publication No. 52-3
1281, Japanese Patent Publication No. 53-47201, Japanese Patent Publication No. 56-4721, etc. These methods involve mixing a small amount of water with a surfactant and injecting it into compressed air to generate bubbles.They have better insulation properties than those based on water, so they are suitable for cutting frozen ground. is suitable. but,
Compressed air becomes hot and needs to be cooled and circulated. In any case, it is necessary to keep the circulating fluid at a low temperature, so conventionally the circulating fluid is cooled on the ground, then pressurized into the top of the tunnel, passed through the tunnel, and ejected from the tip of the sampler to discharge the removed layer to the ground.

If the sample is not removed from the ground, the sample that has entered the sampler must be cut near the tip, and the sampler must be removed to prevent it from falling out when the sampler is lifted to the ground. In the case of compacted ground, devices such as those shown in FIGS. 7 and 8 have conventionally been used.

The one shown in Figure 7 is a tapered ring-shaped Koaki V.
The one shown in FIG. 8 has an outer tube 3 and an inner tube 4, and an inner tube shoe 5 is attached to the inner tip of the tube, and a basket is attached to this. A core catcher 6 of the type is provided.

In the case of a single-tube sampler, a circulating fluid passes between the sample and the tube within one sampler, causing the sample to erode or thaw, so a double-tube sampler is often used.

When using this sampler, when the sample enters the sampler, some of the sand and gravel near the outer periphery of the sample peels off, and this becomes wedge-shaped between the inner surface of the tube and the sample, and when the sample enters the sampler. Core clogging, which increases frictional resistance, has become a problem. Known methods to deal with this include a triple tube type in which a hard vinyl chloride tube is inserted to improve the slippage on the inner surface of the tube, and a flexible ultra-thin duplex that is placed over the X material and inserted into the tube at the same time as the sample. It is being

Problems to be Solved by the Invention With the conventional technique of cooling the circulating fluid on the ground and then pressurizing it from the top of the tunnel, the temperature of the cooled circulating fluid increases before it reaches the tip of the sampler. Thermal efficiency was poor and temperature control was difficult.

In addition, in the conventional technology using a core catcher as shown in Figures 7 and 8, frozen ground has a higher tensile strength than unfrozen ground, so the core catch V- may be damaged or the core (sample) may be left behind. There were problems such as pulling up the sampler while it was still in use.

In addition, methods such as the triple tube type in which a hard vinyl chloride tube is inserted to improve the slippage of the inner surface of the tube, or the method in which a flexible ultra-thin wall tube is placed over the sample, make it easier to extract the sample from the sampler on the ground. Although it has advantages such as not damaging the sample, problems include the lack of suitable ultra-thin walled tubes that are flexible at low temperatures, and the inability to completely prevent core clogging with rigid PVC tubes. It becomes.

Technical Means for Solving the Problems The present invention improves the thermal efficiency for cooling the circulating fluid by installing a cold fill device on the top of the sampler for cooling the circulating fluid.

In addition, in the present invention, by asymmetrically arranging the core catcher provided in the circumferential direction at the tip of the inner tube of the sampler, the cylindrical ground sample is folded as if it were folded, thereby preventing the sample from being left behind or being damaged. ing.

Further, by providing rod-shaped guide members spaced apart in the circumferential direction inside the inner tube, sand and gravel separated from the sample are discharged from between the guide members, thereby solving the problem of core clogging.

Embodiments As shown in FIGS. 1, 2, and 3, a frozen ground sampling device 10 according to the present invention includes a sampler 11A for sampling a ground sample, and a cooling device 11B for cooling a circulating fluid. and has.

The sampler 11A includes an outer tube 12, an inner tube 13, and a sampler head 14 that couples these together. The sampler head 14 is fixed to the outer tube 12, and the inner tube 13 is attached via the inner tube head 15 to the sampler head 14 so as to be relatively rotatable. In addition, the reference numeral 16 indicates a thrust bearing, and the reference numeral 17 indicates a flow path for circulating fluid to promptly discharge cutting waste on the cutting bit surface to the ground.

A pit 18 for ground cutting is provided at the tip of the outer tube 12, and the circulating fluid that has flown down the flow path 17 flows down through the gap 19 between the outer tube 12 and the inner tube 13, and passes through the bit 18. It is designed to be discharged to the ground from the outer periphery of the outer pipe 12.

A core catcher 20 is provided at the tip of the inner tube 13, and a plurality of guide members 21 in the shape of III-shaped rods are mounted inside the inner tube.

The cooling device 11B includes a tubular member 30 having an outer diameter substantially the same as the outer tube 12, a cooling device head 31 identified at one end of the tubular member 30, and an end mounted near the other end of the tubular member 30. A chamber 3 having a plate 32 and containing a cooling heat source.
3 is formed.

A retention tube 34 is installed at the end of the outer tube 12 on the cooling device head 31 side, and serves as a container for receiving large particles that fall when cutting waste is discharged to the ground. In addition, the cooling head 31 is connected to a polling machine (not shown) on the ground, press-fits and rotates the sampler 11A, and serves as a flow path for circulating fluid! 1!71 It is designed to be connected to the tunnel 35.

A cooling pipe 36 is provided within the seedling 33 between the cooling device head 31 and the end plate 32 to exchange heat with a cooling heat source placed in the chamber 33. As the cooling heat source, crushed ice and salt water or water, dry ice, a mixture of dry ice and water, a calcium chloride solution, ethyl alcohol, etc. can be used.

The end plate 32 has an input port 37 for inputting a cold fJJ heat source.
is formed, and fi38 is installed.

Further, a gas vent hole 39 is formed in a part of the cooling device head 31 in case dry ice or the like is used.

As shown in FIG. 3, the guide member 21 has a bar shape with a substantially circular cross section, and in the illustrated example, eight guide members 21 are provided spaced apart in the circumferential direction. As shown, there are upper and lower spring-like centering members 40 for storing the sample.
A and 40B hold it in a predetermined position, and when the soil sample i: 3+ 41 is accommodated in the inner tube 13, the sand and gravel that are separated from this soil sample 41 are held in this guide part vJ21.
It allows you to fall easily through the problems.

The guide member 21 is covered with a tube 43 for reducing 171 dormitories as shown in FIG.
is housed within. Centering member 40B is also attached to guide member 21 by a similar structure.

Next, details of the core key 7 deliverer 20 will be explained with reference to FIGS. 5 and 6.

The core key 7 catcher 20 includes a ring member 45 for incorporating a core catcher attached to the tip of the inner tube 13, and a claw 47 movably attached to the ring member 45 with a pin 46.
, a compression spring 48 that normally presses the pawl 47 radially inward, and a screw 49 for adjusting the force of this compression spring.
and has.

It should be noted that the claws 47 are not evenly arranged in the circumferential direction of the inner tube 13, but are arranged offset on the circumference. That is, they are arranged asymmetrically with respect to the axis of the inner tube 13, so that a biased force can be applied to the ground sample to break it and cut it.

Next, the operation of the frozen ground sampling device 10 according to the present invention will be described.

First, the cooling device 11B is connected to the sampler head 1 on the ground.
4 and remove the lid 38 of the cooling heat source input port 37. The time required for sampling the sample and the appropriate temperature of the circulating fluid are set in advance, the type and distance of the heat source to be input are determined, the sample is placed in the sampler, the lid 38 is closed, and the sample is connected to the sampler 11Δ. The circulating fluid is circulated on the ground to cool the sampler 11A itself, and the temperature of the fluid discharged from the bit 18h is checked. After this, if dry ice is used as the cooling heat source, gas vent hole 3
Confirm that vaporized gas is being discharged from 9.

J3, a backflow prevention 1F valve (not shown) is installed in the gas vent hole 39 (4 pieces).Next, cover the guide part 4421 with the tube 43 for reducing friction, fold up both ends, and attach the centering part. +440A and 40B together with the groove 44, and assemble the number of tubes that will prevent the sample 41 from being eccentric as shown in Fig. 3.The tube 43 for reducing friction is a Teflon duplex with a smooth surface, low frictional resistance, and made of a low temperature resistant material. After assembling the guide rod 21, it is inserted into the inner tube 13 as shown in FIG. 2, and fixed with a ring member 45 for incorporating the core catcher.

In this way, the frozen ground sampling device 10 is assembled, and the ground is frozen and cut using a well-known technique to collect the ground sample 41. During sample collection, the spring 48 of the claw 47 is compressed until the claw 47 is flush with the inner surface of the ring member 45, as the sample 41 enters upward, as shown by the solid line in FIG. When the sample 41 enters the length bracket 11A by a predetermined length, pull out the number plastic plate 10 and the claw 4 will be released.
7 bites into the sample and protrudes inward as shown in FIG. 6, and the sample 41 is destroyed on this surface.

Next, a comparison between the conventional technology and the frozen ground sampling device according to the present invention is as follows.

As a result of conducting this experiment in the summer, with conventional technology, the quality of compressed air was 65°C at the output of the compressor, but when passed through a large air cooling f, fl device, the quality of compressed air decreased to 8°C. . This is passed through an insulated delivery hose to 1I.
ii! Pressure was inserted from the top of the tube, but the temperature at the top of the sampler was 18℃.
It was rising. In this state, a surfactant solution was injected to create a circulating fluid, and a sample was taken. As a result, a portion of the upper surface of the sample had melted, and the sample had partially flowed out in areas where the digging speed was slow. On the other hand, based on the present invention, a circulating fluid cooling station was provided above the sampler and dry ice was placed in it, and as a result, the surface of the collected sample was smooth and the effect was sufficient. However, it was found that if a mixture of dry ice and ethyl alcohol solution was used as a cooling heat source, the temperature would drop too much and foaming would not occur, so using a surfactant diluted with antifreeze instead of water resulted in foaming. The condition of the collected samples was also good.

In addition, when samples were collected using a conventional tapered ring type core catcher, 10 samples were collected, and Gatsuchi 17-1iffl I[! There was one failure due to the gear fitting V- and test J'l slipping and cutting the sample in the middle.
All the books and samples were left behind, and one tree and the other six trees were successfully collected. On the other hand, with the pot core catcher according to the present invention, only one core slipped and was cut off in the middle by sample 1'31, and the others were collected normally. Furthermore, when comparing the case of using a normal double-tube sampler and the case of using the elongated rod-shaped guide member of the present invention, there was no clear difference in the influence of core clogging, but the sampling time was It was possible to shorten the time by about 80%. In addition, when using a conventional sampler to remove the sample from the sampler, it was not possible to remove the sample smoothly and 2 out of 10 samples broke in the middle, whereas the sampler with the built-in guide member according to the invention can be removed easily. I was able to do that.

Effects of the Invention As described above, the present invention has the effect of extremely efficiently cooling the circulating fluid that discharges cutting waste to the ground. Further, according to the features of the present invention, it is possible to easily cut the ground sample, and at the same time, it has the effect of reducing damage to the sample caused by sand and gravel peeled off from the ground sample.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a frozen ground sampling device according to the present invention;
Figure 2 is an enlarged cross-sectional view of the main part of the sampler shown in Figure 1, Figure 3 is a cross-sectional view taken along the line ■-■ in Figure 2, and Figure 4
The figure is an enlarged sectional view showing the main part of the guide member of the frozen ground device shown in Fig. 1, and Fig. 5 is an enlarged sectional view showing the core axis ψ- of the frozen ground sampling device shown in Fig. 1. , FIG. 6 is a sectional view taken along the line Vl-Vl in FIG. 5, and FIG. 7 is a diagram showing a part of a sampler according to the prior art.
2) is a sectional view thereof, (c) is a perspective view of the core gear V-zigger, and FIG. 8 is a sectional view of a sampler according to Haku's prior art. 10...Frozen ground sampling device, 11A...
... Sampler, 1113 ... Cooling device, 1
2...Outer pipe, 13...Inner pipe, 14...
... Sampler head, 18... bit,
20...Core catcher-121...
Guide member, 30... Tubular member, 33...
...Chamber, 35...Digital pipe, 36...Cooling pipe.

Claims (2)

[Claims] (1) A sampler having an outer tube for cutting frozen ground, an inner tube provided within the outer tube for collecting a ground sample, and a sampler head that connects the outer tube and the inner tube; a cooling device attached to the sampler, the cooling device having one end connected to the sampler head and the other end connected to a bore pipe for operating the sampler for internal cooling. A tubular member forming a chamber for containing a heat source, and a cooling pipe provided in the chamber so as to exchange heat with the cooling heat source placed in the chamber, and when cutting frozen ground with the outer pipe. 1. A frozen ground sampling device, characterized in that a fluid for discharging cutting waste generated on the ground to the ground is cooled by passing the fluid through the cooling pipe. (2) a sampler having an outer tube for cutting frozen ground, an inner tube provided within the outer tube for collecting a ground sample, and a sampler head for coupling the outer tube and the inner tube; a cooling device attached to the sampler, the cooling device having one end connected to the sampler head and the other end connected to a bore pipe for operating the sampler for internal cooling. A tubular member forming a chamber for containing a heat source, and a cooling pipe provided in the chamber so as to exchange heat with the cooling heat source placed in the chamber, and when cutting frozen ground with the outer pipe. In the frozen ground sampling device, a core catcher is installed at the tip of the inner tube with respect to the longitudinal axis of the inner tube. A frozen ground sampling device characterized in that a plurality of elongated rod-shaped guide members are provided asymmetrically and spaced apart in the circumferential direction for guiding the ground sample inside the inner tube.