JPS62140043A - Adiabatic apparatus sampling frozen ground specimen - Google Patents

Abstract

PURPOSE:To minimize heat loss by preventing the bending or inclination of a frozen hole and to enable the sampling of a specimen without disturbance by holding underground stress, by forming a guide hole for drilling the frozen hole to a columnar main body formed of a heat-insulating member so as to have a desired dimension in the axial direction thereof. CONSTITUTION:An adiabatic apparatus 100 has a columnar main body having a cross-sectional dimension fitted to the part to be frozen of the grounded almost entirely formed of a heat-insulating member. The main body is constituted so as to connect an upper part 103, a middle part 104 and a lower part 105 by a connection metal fitting 106 and a guide hole 109 for drilling a frozen hole 108, a guide hole 11 for drilling a ground specimen sampling hole 110 and a guide hole 113 for drilling temp. measuring hole 112 are formed to the main body in the internal axial direction thereof. At first, an open end pipe 102 is used to drill a large caliber boring hole and the adiabatic apparatus 100 is arranged in said hole. Next, the frozen hole 108 is drilled down to the lower part of a freezing limit depth to form frozen soil 121 having a desired size. A specimen not disturbed can be sampled from the sampling hole 110 through the guide hole 111.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention freezes sand and wall MRI, thereby cutting the ground to a predetermined diameter while maintaining underground stress, and collecting undisturbed ground samples. The present invention relates to a heat insulating device for collecting samples from frozen ground, and particularly relates to a heat insulating device suitable for collecting deep ground samples such as WJ21, which freezes the ground only in a limited portion of the deep layer of the ground.

Conventional technology! I! l? Various conventional techniques are known for freezing a predetermined deep part of J and collecting ground samples from this deep part.

For example, in the example shown in Fig. 5 (2), υ, freezing hole 1 is first drilled, and freezing is carried out in this hole! ! 2 is inserted to insulate the unfrozen part near the ground surface from freezing, and create frozen soil 3 in the C-limited frozen part. When the frozen soil 3 reaches a predetermined size, a sample collection hole 5 is drilled through a sample collection hole guide vibrator 4 to collect a sample 6 without disturbing it.

In the conventional technology shown in Figures (2) and (C) of W46, several freezing holes 11 are drilled from the ground, freezing holes 1 and 12 are inserted, and the insulation is treated in the same way as in the case of Figure 4. Tekara Frozen Earth 13
A sample sampling hole 15 is drilled through the sample sampling hole guide vibrator 14. There are various ways to arrange freezing holes 1.11 and sampling holes 5.15, and methods such as burying soil temperature detectors (not shown) are also used to confirm frozen soil creation. ing.

In each of the embodiments shown in FIGS. 7 and 8, large-diameter poling is first carried out to near the upper limit freezing depth, and then FI coking hole sample collection holes are drilled.

In the second embodiment shown in FIG. 7, a large poling hole 20 is formed by advanced large-diameter poling, and then the guide tubes 22 and 24 of the freezing hole 21 and the sampling hole 25 are connected using a centizer (not shown) or the like. Position and large diameter poling hole 2
0 to the bottom, drill a freezing hole 21, insert a freezing pipe (not shown) into this hole, and freeze the frozen soil 23 at the limited depth.
Create. Then, a sample sampling hole 25 is formed via the sample sampling hole guide vibe 24. In this case, guide tube 2
2 has insulation 9! Ill is often applied. Furthermore, since the large-diameter poling hole 20 is generally filled with muddy water, measures such as stirring are taken to prevent it from freezing.

In the conventional technique shown in FIG. 8, after forming a large-diameter poling hole 30, a poling machine or the like is installed at the bottom of this large-diameter poling hole 30, and then a freezing hole 31 is drilled to remove frozen soil 33. Create. Then, while drilling a sample sampling hole 35 in this frozen soil 33, an undisturbed sample 36 is sampled.

In each of the embodiments shown in FIGS. 9 and 10, a test sample is collected on the ground after a frozen soil column is pulled out.

The conventional technique shown in FIG. 9 is applied when the non-freezing depth is shallow, and a freezing hole 41 is drilled and a freezing tube (
(not shown) is inserted to create frozen soil 43. in this case,
The non-freezing portion is subjected to a heat insulation treatment 42. After the frozen soil 43 is created in this way, a large-diameter core tube 44 is used to drill holes near the outer periphery of the frozen soil 43 for edge cutting, and then the frozen soil pillar is pulled up. Note that if the pulling force is small, the frozen soil column may be pulled out without cutting the edges.

FIG. 10 shows a case where the limited freezing depth is deep, and a large-diameter poling hole 50 is formed by large-diameter poling up to the vicinity of the upper surface of the limited freezing, and a guide tube 52 for drilling the frozen hole 51 is connected using a centrizer or the like. Advanced hole 5 while positioning
0 to the bottom, an i-tube hole 51 is drilled, and a frozen pipe (not shown) is inserted into this hole to create frozen soil 53. At this time, the muddy water in the large-diameter poling hole 50 is stirred and the guide 'Q52 is heat-insulated to prevent it from freezing.

When the frozen soil 53 reaches a predetermined shape, a large-diameter core tube 54 is used to cut holes at the edges and pull up the frozen soil. Since this construction method requires ** processes, various methods have been devised. For example, Japanese Patent Publication No. 60-100737 falls under this category.

Problems to be Solved by the Invention The essential difference between the conventional techniques shown in FIGS. 5 and 6 is that the sample is collected around one freezing hole or in several freezing holes. In terms of whether to collect samples after creating frozen soil, it is better to collect samples without disturbing it.When fine-grained soil is mixed with sand or turf, if you create frozen soil using the latter method, the ground will be disturbed during freezing. The only point is that there is fear. In either case, with these conventional techniques in which freezing holes and sampling holes are drilled separately from the ground surface, hole surface cambers and inclinations occur during drilling, so it is necessary to position each hole with a considerable distance between them. .

Therefore, the biggest problem is that the freezing range must be enlarged. Especially when the limited freezing depth is deep, it is virtually impossible to drill the desired hole.

In the conventional technique shown in FIG. 7, the guide tubes for 211 conduits and sample collection are provided individually or in combination! Since the pipe is inserted into a large-diameter poling hole with a frame made of LL material, etc., and the surrounding area is filled with muddy water, anti-freezing measures are required, and heat loss from the guide pipe and the bottom of the large-diameter poling hole is large. At the same time, problems include the disturbance of the ground at the bottom of the hole due to large-diameter poling and the fact that it does not freeze while retaining the underground stress because the upper pressure is removed when it freezes.

In the conventional technique shown in FIG. 8, the polling device! !
etc. must be installed at the bottom of the large-diameter poling hole, which is difficult when the groundwater level is shallow, and the necessary hole diameter of the large-diameter poling hole must be determined based on the work space rather than the location of the sampling hole. In addition, similar to the prior art shown in FIG. 6, there are problems such as large heat loss from the bottom of the large-diameter poling hole and release of underground stress.

The conventional technique shown in FIG. 9 has no particular problem when the unfreezing depth is shallow, but it is difficult to use this technique when the unfreezing depth is deep.

With the conventional technology shown in Figure 10, it is necessary to continuously stir the muddy water in the large-diameter poling hole during the freezing operation to prevent it from freezing, and it is also necessary to directly obtain horizontal information on the frozen area and soil temperature. There are drawbacks that cannot be achieved. Further, this conventional technique has disadvantages of large heat loss at the bottom of the large-diameter poling hole and release of underground stress. Furthermore, in this conventional technology, when performing edge-poling around the outer periphery of a frozen soil column, a head is attached to the large-diameter core tube 5 to pump the cryogenic circulation ffi fluid, so the freezing pipe and measurement cables, etc. must be removed. There are problems such as the pillars thawing and heat management being impossible.

To summarize the above, in deep frozen ground sampling,
Caving and sloping of the holes must be prevented and effective insulation must be provided to minimize heat loss. Furthermore, in order to save costs, it is necessary to minimize the freezing range, and for this purpose, temperature control must be carried out effectively. Furthermore, the subsurface stress must be maintained correctly in order to obtain a correct and undisturbed sample.

However, it has been difficult with conventional techniques to simultaneously satisfy all of these requirements.

It is therefore an object of the present invention to provide a thermal insulation device for frozen ground sampling that can simultaneously meet these requirements.

Means for Solving the Problems The insulating device for sampling frozen ground according to the present invention comprises a columnar body formed almost entirely of a heat insulating member and having transverse dimensions adapted to the portion of the ground to be frozen. The main body has a guide hole for freezing the hole formed in the axial direction.

Operation To use the heat insulating member for sampling frozen ground according to the present invention, first, a large-diameter poling hole of desired size is drilled, and the column-shaped heat insulating device according to the present invention is inserted into the hole and placed on the bottom of the hole. I do it. Next, frozen soil of a desired size is created using the guide hole for general freezing, and then a desired sample can be collected using the guide hole for collecting the sample.

Embodiment In the embodiment shown in FIG.
is raised above the ground surface for above-ground piping such as low-temperature fluid and exhaust pipes for freezing underground windows, and the mouth pipe 102 is for carrying large-diameter polling (1).In this embodiment, The heat insulation device according to the present invention!!1
00 is divided into an upper part 103, a middle part 104, and a lower part 105, which are connected to each other by a connecting fitting 106. L1 hole prevention ±107 is provided to improve the fit between the lower bottom surface of the heat insulating device ioo and the original ground and to prevent it from penetrating the adjacent polling hole.

Insulation [fl 00 (7) Upper m1103, middle W104 and 1st part 105 each have a guide hole 109 for drilling a freezing hole 108, which goes in the ward direction as shown in Fig. 2. , a guide hole 111 for drilling a ground sample sampling hole 110, and a guide hole 113 for drilling a temperature measurement hole 112 are formed in the axial direction, and various temperature detectors to be described later are installed on the outer periphery of these holes. Cable extraction hole 11 for pulling out cables for 114, 115, 116, etc.
7 is formed.

Each W103, 104, 105 is substantially made of a thermally insulating material, the outer periphery of which can be covered with a plastic or metal plate or the like as required.

Furthermore, the weight can be increased by covering the outer periphery with steel or the like to compensate for the reduction in underground stress caused by large-diameter poling. These parts 103, 104, and 105 are basically the same, but 1. A freezing hole 10 is provided on the upper surface of the L portion 103.
The exhaust port connection pipe connected to the 8, the indigo of the sample collection hole 110, etc. are S [4].

Next, the working procedure for using the heat insulation table 2100 will be explained.

First, the hole 102 is placed underground and a hole is drilled from the upper part of the non-freezing part to the diameter of the hole by large-diameter boring.The lower part 105 of the heat insulating device 100 is lowered, and the middle part 104 is connected to it and the inside of the hole is drilled. Drop it off, aII! ! Connect the upper part 103 to the hole and lower the work stage 101! Place Q.

Next, using the guide hole 109, a freezing hole 108 is drilled to the bottom of the freezing limit depth, and after inserting the freezing outer tube and inner tube therein, the cryogenic fluid piping is performed.

Next, a measurement hole 112 is drilled using the guide hole 113, a soil temperature detector 116 and a resistivity measurement electrode 120 are buried so as to make contact with the hole wall, and then cryogenic fluid is injected into the freezing hole 108. Frozen soil 121 of a predetermined size is created while performing thermal management.

Next, an undisturbed sample is collected from the sample collection hole 110 through the guide hole 111 for first sample collection, and after this work is completed, it is mixed with sand and water that have been kept at a low temperature so as not to penetrate the hole during the next sample collection. Place the soil temperature detector into the hole and refreeze it before drilling the next sampling hole. In addition, the temperature of the temperature sensor 114 shown in FIG. 1 is measured at the initial stage of freezing, and it is determined that the freezing progresses from the lower part of the heat insulating device 100 and that the thawing caused by the antifreeze does not invade the lower part of the pipe body within the sampling date. When freezing has progressed, an antifreeze solution such as chloride Rushum's solution is injected into the muddy water between the large-diameter poling hole wall and the pipe body through the hole to prevent unfrozen parts from freezing due to the difference in specific gravity. Facilitates recovery of pipe bodies after work is completed. The periphery and bottom of the lower part of the tube are protected by a Teflon sheet or the like to prevent freezing.

The temperature sensor 114 is provided to ensure proper freezing between the heat insulating device 1100 and the wall of the large-diameter poling hole. Moreover, the temperature sensor 115 is for measuring the horizontal growth of frozen soil, and the temperature sensor i! ! Reference numeral 116 is for measuring the growth and temperature of frozen soil in the depth direction.

The resistivity detector 120 is used to obtain information such as soil saturation and salinity, and has electrodes arranged in pairs at predetermined intervals.

If the stratum up to the upper surface of the limited freezing depth is unconsolidated sand or soft cohesive soil that is easy to drill, attach a drilling bit like the one shown in Figure 3 to the bottom of the insulation 1utioo and drill while drilling. Insert the tube to a predetermined depth, freeze the ground as described above, and collect a sample without disturbing it. This insulation device m1oo has a guide hole 109 of the freezing hole 108, a guide hole 113 of the measurement hole 112, a guide hole 111 of the sample sampling hole 110, a detector 115 for horizontal soil temperature measurement, and It has a lead wire extraction hole 117, a large-diameter drilling pit 122, and a pedestal 123.

Using a large poling machine, a hole is drilled to a predetermined depth through an F1100 insulation device whose outer periphery is reinforced with steel plates, and then frozen and sampled.

According to the conventional technology, the shortest number of days required to freeze the ground is at least one day even when liquid nitrogen at -196°C is used, and if the diameter of the frozen ground becomes large, it takes 3 to 7 days, during which time the hole wall If the pipes collapse, it may be difficult to pull them up to retrieve them after work is completed.

Therefore, the inside of the large-diameter casing was filled with heat insulating material, and an insulating pipe was inserted above the part of the guide pipe at the bottom of the multifunctional composite pipe body to prevent heat conduction from the pipe itself.The connections between each pipe and the bottom plate were welded. The structure is designed to prevent deformation due to thermal stress and to prevent the sample collection guide tube from becoming cold by connecting bolts with a gap between them, rather than using a tight contact method such as the method shown in Figure 1. As a result, the thermal efficiency, that is, the consumption of liquid nitrogen, was 10 to 10%, although it varied depending on the ground conditions and the limited freezing depth.Since there were no operational troubles, the process, especially the sample wiping time, was shortened by about half. It was also possible to improve the quality of sample collection.

The embodiment shown in FIG.
This is a method of creating frozen soil pillars using 0A and pulling them out.

The heat insulation ￥Rffi100A in this embodiment is the same as the heat insulation Vtn1oo shown in FIGS. 1 and 2 and the V main fishing. It is something that has been established.

The lower part of the pressure feed pipe 132 is located near the lower end of the heat insulating pipe 100A, and an outlet 133 is provided.

In this embodiment, the base pipe 102 is first installed, and a hole is drilled to the bottom of the heat insulating device 100A by auger poling or the like.
Large diameter casing pipe 130 with pit 131 at the lower end
Insert to the top of the non-freezing depth.

A heat-insulating F1100A is installed at the bottom of a large-diameter poling hole, a guide tube 134 is inserted into the guide hole 109, and a freezing tube 135 is inserted into this to create a frozen soil column 136. The construction of frozen soil pillars 136 and the burying of measurement holes, temperature detectors, etc. for thermal management are the same as those shown in FIGS. 1 and 2. When the frozen soil column 136 reaches a predetermined size, a heat-insulated guide 1!134, a freezing pipe 135, a circulating fluid pressure feeding pipe 132, and a large-diameter casing pipe 130 are added, and the pressure feeding pipe 132 is connected while performing freezing management. A low-temperature fluid is injected through the pipe, and while the large-diameter casing pipe 130 is rotated, the vicinity of the outer periphery of the frozen soil column is cut as shown by point 11137 in FIG. The pressurized circulating fluid 138 is controlled to be near the upper surface of the large-diameter casing 137, and this pressure difference causes cutting waste from the bit surface to be discharged to the ground through between the outer surface of the large-diameter casing 137, the ground, and the mouth pipe 102. do. After drilling a hole to the lower end of the frozen soil column 136, the large-diameter casing 1
37 and the frozen soil pillar.

According to this embodiment, the above-mentioned effects of the embodiment shown in Figs. 1 and 2 can be obtained except for the sample collection part, and furthermore, heat management can be performed while drilling around the frozen soil column. In the prior art, the upper part of the frozen soil column had thawed and become thinner, and frozen soil of a predetermined uniform diameter could not be collected, but it was possible to pull up a uniform frozen soil column. Insulation during drilling @l11
In order to prevent 00A from turning around with the casing pipe for drilling, the protruding length of the guide pipe for the 11@ hole and measurement hole was made longer, and the bottom plate was made to come into direct contact with the frozen soil, thereby ensuring sufficient freezing power. I was able to make it work.

As described above, according to the present invention, insulation @r! By using the guide hole I, it is possible to effectively prevent the hole surface from tilting and tilting, and by using a heat insulating material, it is possible to prevent frost 18
The heat loss of W8 can be minimized, and an effect can be obtained that an undisturbed ground sample can be collected while maintaining underground stress.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing a method for collecting ground samples using the heat insulating device according to the present invention, Fig. 2 is an enlarged bottom view of a heat insulating VL installation, and Fig. 3 is an enlarged bottom view of a heat insulating device according to another embodiment. 4 is a cross-sectional view showing a method for collecting ground samples according to a more relaxed embodiment of the present invention, and FIG. 5 is a view showing the conventional technique. 6 is a diagram showing another conventional technique, (2) is a longitudinal sectional view, (c) is a sectional view taken along line Vl--Vl, and FIG. 7 is a diagram showing another conventional technique. In the drawings showing the technology, (2) is a longitudinal cross-sectional view, υ is a cross-sectional view along the line Vl-■, and FIG. ) is a sectional view taken along the line 1--2, FIG. 9 is a sectional view further showing a prior art technique, and FIG. 10 is a sectional view showing still another prior art technique. 100.100A...Insulation device, 102...
... Mouth canal, 103 ... Upper part, 104 ...
...Middle part, 105...Bottom part, 106...
... Connection fittings, 108 ... Freezing hole, 109 ...
...Guide hole, 110 ... Ground sample collection hole, 111 ... Guide hole, 112 ... Temperature measurement hole, 113 ... Kite hole, 114.115.116...Temperature detector, 11
7... Cable extraction hole.

Claims (1)

[Claims] In an insulating device for collecting frozen ground samples, which freezes sand, gravel, etc. in deep layers, cuts the ground to a predetermined diameter while maintaining underground stress, and extracts undisturbed ground samples from underground. , having a columnar body having a transverse dimension suitable for the portion of the ground to be frozen and made almost entirely of a heat insulating material, and having a guide hole etc. for drilling a freezing hole in the body. , a heat insulating device for collecting frozen ground samples characterized by being formed in the axial direction.