JPS6319677B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method and apparatus for observing and surveying boreholes in soil survey work. The scope of use of underground boring observation technology has been expanded to a wide range of fields, and it has become an important technology not only in the academic fields of geotechnical engineering and petrology, but also in various construction fields such as pipelines, water supply and sewerage systems, tunnels, and vertical shafts. As a result, the demand for detailed investigations of borehole walls is increasing. Generally, the geological strata that are the subject of such soil surveys are often soft, so making the borehole walls self-supporting is an essential issue for observing inside the borehole. Normally,
By filling a borehole with bennite-based mud, causing the mud to form a mud film on the wall of the hole, and applying mud water pressure to the mud film,
A treatment method is used to stabilize the hole walls. However, if this muddy water and mud film exist, it is impossible to observe the hole wall, so the muddy water must be drained and the mud film must be removed. However, this complete cleaning is not easy, and if even a small amount of muddy water remains, If the mud film remains, if you insert an observation device such as a television camera or periscope into the hole and observe it, you will see muddy water or a mud film instead of the geology. For example, when cleaning the hole wall with fresh water, there is a risk that the hole wall will collapse, and the desired depth may not be reached, or collapse may occur during observation, requiring expensive observation equipment. It can cause damage or even bury it completely. In geological surveys, soft layers, cobblestone layers, and fractured zones are the most interesting areas, and we want to observe the details of those zones accurately, but on the other hand, such zones are often damaged due to the collapse of the hole walls as described above. This is also the place where you are most likely to lose your expensive observation equipment. For this reason, some conventional observation devices are now equipped with sophisticated warning systems that immediately send warning signals to the ground if a collapse is about to occur. However, in reality, even if this warning signal is issued, collapse cannot be prevented, and even when this device is used, cases have been reported in which the signal was still lost. The present invention aims to solve such problems in observing the walls of boreholes. For this purpose, the present invention provides a method of injecting a transparent liquid consisting of an aqueous dispersion of a superabsorbent resin into an excavated borehole and inserting an observation device into the liquid to observe the inner wall of the hole. . The superabsorbent resin to be water-dispersed may be a material known per se with high water absorption performance, such as starch-acrylonitrile, starch-methacrylate graft copolymer, polyacrylonitrile, vinyl ester-ethylenically unsaturated carboxylic acid, etc. Partial hydrolysates of copolymers, polymers with hydrophilic groups introduced such as sulfonated styrene, polyethylene oxide, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, polyacrylamide, carboxymethyl cellulose, sodium polyacrylate,
Radiation-irradiated products of water-soluble polymer compounds such as acrylamide copolymers and bullulane, crosslinked products with crosslinking agents such as methylene bisacrylamide, dichloroacetic acid, epichlorohydrin, and aldehydes, and some of the hydrophilic groups have been replaced with lipophilic groups. Examples include copolymers of isobutylene and maleic anhydride. When such an aqueous dispersion of a superabsorbent resin is charged into a borehole, the borehole wall can be stabilized, and collapse of the borehole can be effectively prevented.
This is thought to be due to the interaction between the clogging effect of the wall surface caused by the superabsorbent resin and the application of liquid pressure due to the presence of liquid in the pores. Therefore, by injecting this transparent water dispersion of super absorbent resin into the borehole after drilling (or in some cases during drilling), the wall surface can be stabilized and maintained in the excavated state. By inserting an observation device such as a television camera or periscope into this liquid, the hole wall can be clearly observed, and damage to equipment due to hole wall collapse can be prevented. At that time, if muddy water is present in the borehole due to spring water or other sources, or if muddy water is actively made to exist from the viewpoint of forming a mud film as described above, this muddy water and the transparent After replacing the liquid with the liquid, the observation device can be inserted into the liquid. This replacement may be carried out by forcing the transparent water into the lower part of the muddy water in the hole through a pipe or the like to push the muddy water up to the surface. More preferred. In the present invention, as a method for implementing this,
When the transparent liquid is injected into the lower part of a borehole where muddy water is present, a member that floats up while sliding against the hole wall as the transparent liquid is injected is present at the boundary between the muddy water and the transparent liquid. devised a replacement cleaning method and device. This replacement cleaning method will be explained in detail below, along with the equipment members used therein, with reference to the drawings. FIG. 1 shows a state just before the displacement cleaning device of the present invention is inserted into a borehole 1 in which muddy water is present. This displacement cleaning device has a liquid supply pipe 2
(The boring rod itself can be used for this purpose.), a sponge material 3 attached to the tip of the liquid feeding pipe 2, a fastener 4 for reducing the diameter of the sponge material 3, and a fastener 4 for reducing the diameter of the sponge material 3. It consists of a fastener release means for releasing the lock (an example is shown consisting of a fastener 5, a fastening pin 6, and a pull-out string 7). FIG. 2 shows an example of the shape of the sponge material 3, and a cylindrical material having an inner hole 8 into which the liquid feeding tube 2 is inserted is used. The outer diameter d ₂ of this sponge material is normally slightly larger than the inner diameter d ₁ of the borehole, and the inner diameter of the inner hole 8 is made large enough to freely slide into the liquid feeding pipe 2 . FIG. 3 shows an example of a fastener 4 made of sponge material 3. This is done by tightening the sponge material 3 inserted into the tip of the liquid feeding tube 2 from the outside.
This is to reduce the outer diameter of the borehole ₁ to be smaller than the inner diameter d1 of the borehole 1. In the illustrated example, this fastener has fasteners 5 attached to both edges of a woven fabric, non-woven fabric, or net, and the width d ₃ of this fastener 4 satisfies the relationship d ₃ <πd _1. It's satisfying.
FIG. 4 shows a stop pin 6 that is passed through the stopper 5. After inserting the sponge material 3 into the tip of the liquid feeding tube 2, wrap it with the fastener 4 from the outside. When the fixing pins 6 are inserted into the fixing fittings 5 on both edges, the sponge material 3 is fixed at the tip of the liquid feeding pipe 2, as shown in FIG. The diameter is reduced to a size that can be inserted into the A pull-out string 7 is attached to this stop pin 6, and this string 7
By pulling up the stop pin 6, the stop metal fitting 5
It can be freely removed from the Although the sponge material 3 shown in Fig. 2 shows an example in which the outer surface is flat, it is possible to use a material with an uneven outer surface, or to use materials with different outer diameters in multiple stages. (the diameter increases as it goes downward), or a plurality of sponge bodies may be stacked vertically. In addition, although a cloth-like fastener 4 is shown, it may be any material that can reduce the diameter of the sponge material 3 to be smaller than the diameter of the borehole. It is also possible to cancel the diameter. FIG. 5 schematically shows a working procedure in which muddy water in a borehole is replaced with the transparent water using this apparatus, and at the same time, the inner wall of the borehole is cleaned and then observed. In FIG. 5, the work procedure progresses in order from a to f. 1A shows the state shown in FIG. 1, that is, the state in which the boring rod 2 with the sponge material whose diameter has been reduced in the manner described above is attached to the tip thereof is directed toward the borehole 1 where muddy water 9 exists on the ground. The boring rod 2 is inserted into the ball ring hole from the state shown in a, and the state shown in b is when the tip end reaches almost the lowest end of the muddy water 9. At the time of insertion, the pull-out cord 7 is let out so that the other end remains on the ground. Next, when this pull-out string 7 is pulled up on the ground, the stop pin 6 is moved to the stop metal fitting 5.
(Fig. 3), and the locking of the sponge material 3 by the fastener 4 is released at the bottom of this muddy water.
The sponge 3 expands and expands in diameter to return to its normal state.
This state is c, in which the sponge 3 is in contact with the hole wall and the contact resistance with the boring rod 2 is relaxed. Next, as shown in d, when the transparent liquid made of the aqueous dispersion of the superabsorbent resin described above is pressurized into the hollow pipe of the boring rod 2 using a pump, the transparent liquid 10 is poured from the tip of the rod 2. is press-fitted into the borehole below the sponge 3, and as the transparent liquid is press-fitted, the muddy water 9 is pushed upward and the sponge material 3 is floated and moved accordingly. If the inner hole 8 (Fig. 2) and outer diameter _d2 of the sponge material 3 are set to an appropriate size with respect to the outer diameter of the rod 2 and the borehole diameter _d1 , this transparent liquid 10 and muddy water 9
The transparent liquid 10 allows the muddy water 9 to flow out onto the ground while maintaining the state in which the sponge material 3 exists at the boundary with the transparent liquid 10. In this case, the sponge material 3 acts as a baffle material that prevents mutual diffusion of the transparent liquid 10 and the muddy water 9. On the other hand, due to the floating movement of the sponge material 3, since the sponge material 3 normally has a diameter larger than the diameter of the borehole, the action of washing away the mud film adhering to the hole wall is provided. In this way, the sponge material 3 floats to the top of the borehole,
This shows the state where muddy water has been replaced by transparent liquid. If a sufficient mud film cleaning effect cannot be obtained by one-time replacement, steps a to e may be repeated. By the above steps a to e, the muddy water is replaced with the transparent water dispersion of the superabsorbent resin, the mud film is washed, and the pore walls are stabilized by this liquid. f is a borehole television camera 1 in this liquid.
1 is inserted to observe the soil quality of the hole wall, and the hole wall can be clearly observed without the risk of collapse of the hole wall. Table 1 below shows the boreholes in the sand and gravel layer shown in the histogram shown in Figure 6 (Example 1) and the boreholes in the sand and silt layer shown in the histogram shown in Figure 7 (Example 2). This is a summary of the specifications and results obtained when the invention is implemented.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a partial perspective view of an apparatus used to carry out the method of the present invention, FIG. 2 is a perspective view showing one example of the shape of the sponge material, FIG. 3 is a front view showing one example of the fastener, and FIG.
The figure is a front view showing one example of a locking pin, Fig. 5 is an illustrated process diagram showing the procedure of the method of the present invention, Fig. 6 is a cylindrical view of a borehole that was carried out, and Fig. 7 is a diagram of another borehole that was carried out. It is a histogram. 1... Bore hole, 2... Liquid feed pipe (boring rod), 3... Sponge material, 4... Fastener, 5... Stopper, 6... Stopping pin, 7... Pull-out string, 9... Muddy water, 10... High water absorption Aqueous dispersion of resin (transparent liquid),
11...Observer.

Claims (1)

[Claims of Claims] 1. Boring comprising injecting a transparent liquid consisting of an aqueous dispersion of a superabsorbent resin into an excavated borehole, and inserting an observation device into the liquid to observe the inner wall of the hole. Observation method inside the hole. 2. A transparent liquid consisting of an aqueous dispersion of a superabsorbent resin is placed in the lower part of the borehole where muddy water is present, while a member that floats up while sliding against the hole wall as the transparent liquid is injected is present in the hole. A method for observing the inside of a borehole, which consists of inserting an observation device into the liquid and observing the inner wall of the hole after the muddy water in the hole is substantially replaced by this transparent liquid. 3. A liquid pipe for sending liquid to the lower part of the borehole, a sponge material that is slidably attached to the liquid pipe and has an outer diameter that is normally larger than that of the borehole, and a sponge material that covers the liquid pipe. A method for displacing muddy water and mud for use in a method for observing inside a borehole, which comprises a fastener for reducing the diameter of attached sponge material, and a fastener release means for releasing the fastener by remote control. Equipment for membrane cleaning.