JPS61211417A - Grouting method and device - Google Patents

Abstract

PURPOSE:To pour a grout material over a wide range of a ground having the low coefficient of water penetration, by a method wherein, after a dried compressed gas is sucked in an excavated hole to form an air-permeable pass around the hole, the grout material is blown in the hole to inject it to the air- permeable pass. CONSTITUTION:Gas and liquid are sucked through a second hole 34 with the aid of a suction mechanism 24, and the surrounding of a first hole 32 is kept in a negative pressure state. A compressed air in a tank 52 is fed to a first pipe 12 to blow it out through a slit 26 in a ground 30 to form an air-permeable pass around the hole 32. In a state that a compressed air is continued to be blown into maintain the air-permeable pass, a grout material is poured from a feed mechanism 22 to the ground 30 through the first pipe 12 together with the compressed air.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a grouting method and device using gas, and particularly to a grouting method and device suitable for improving soft rock-based ground, for example.

(Prior art) Soft layers such as sand layers, gravel layers, jilton layers, soft rock layers, etc.! ! Grouting method is used to improve the board.

One of the grouting methods is to place a spout pipe into a hole drilled in the ground by a poling machine, and spout grout mixed with a hardening agent and liquid from the spout pipe into the hole, thereby applying the grout to the ground. There is a way to press it in.

However, since the viscosity of liquid is higher than that of gas, in the case of ground with a low permeability coefficient, this method is ineffective because the grout material only penetrates into a thin layer near the hole drilled in the ground. There is no.

As another grouting method, Japanese Patent Application Laid-Open No. 54-30
As described in Japanese Patent No. 808, there is a method in which powdered grout is directly blown into the ground together with air (hereinafter referred to as a simultaneous grout injection method).

However, in the simultaneous grout injection method, compressed air and grout are blown into the ground at the same time, so the grout adheres to soil particles in the ground and fills minute gaps in the ground.
Provides resistance to the flow of compressed air. For this reason, the method of simultaneously injecting grout has a limit in injecting grout over a wider area of the ground.

(Objective of the Invention) An object of the present invention is to provide a grouting method and apparatus that can inject grout over a wide range even in ground with a low hydraulic conductivity.

(Structure of the Invention) The grouting method of the present invention involves drilling a hole in the ground, blowing compressed gas into the hole after drying to form an air passage around the hole, and then grouting the grout while maintaining the air passage. blowing into the hole and injecting into the airway.

The grouting method of the present invention also provides i′I! First and second holes are bored in Im, and while gas and liquid are sucked through the second hole, the compressed gas is dried and then blown into the first hole to create an air passage around the first hole. and then blowing grout into the first hole while maintaining the air passageway and injecting it into the air passageway.

The grouting device of the present invention includes a blowout pipe inserted into a hole drilled in the ground, a compressed gas generation mechanism, a dryer for drying the compressed gas, and a dryer for drying the compressed gas that has passed through the dryer. The apparatus includes a guide pipe leading to the pipe, and a mechanism for supplying grout material to the spout pipe via the guide pipe.

The grouting device of the present invention also includes first and second pipes inserted into the first and second holes bored in the ground, respectively, a compressed gas generation mechanism, and a mechanism for drying the compressed gas. a dryer, a guide pipe that guides the compressed gas that has passed through the dryer to the first pipe, a mechanism that supplies grout material to the first hole through the guide pipe, and from the second pipe. and a suction mechanism for suctioning gas and liquid.

Here, the air permeable passage refers to a space through which gas such as air can pass through by enlarging the gaps between ground particles and/or eliminating pore water present in the gaps.

(Effects of the Invention) According to the present invention, since the compressed air blown into the hole is dried, the compressed air expands the gap between the ground particles around the hole, and the gaps between the ground particles existing in the gap are expanded. By eliminating pore water, a permeable channel through which gas can pass is formed over a wide range around the hole, and moisture adhering to ground particles is vaporized by dry air, reducing the cross-sectional area. Small air passages are also formed, and said air passages are formed over a wider area. Further, since the gaseous grout is injected into the hole while maintaining the air permeability path, the grout is injected through the hole over a wide area around the hole even if the ground has a low permeability coefficient.

That is, compressed air and water are standard conditions, i.e. 7
Under f3hmHg and 206C, the ratio of the air permeability coefficient, which is the speed of passage through the ground of unit cross-sectional area, to the hydraulic permeability coefficient, which is 2, is if the flow conditions of air and water in the ground are the same. , approximately equal to the ratio of the viscosity coefficients of air and water. Here, 3 is the viscosity coefficient of air, K4 = 1.81 x 10"" g/cm sec
and the viscosity coefficient of water is 4, K4 = 1.002 x 10-2g/cm sec
Therefore, K3/K4 becomes 1155. Therefore, it can be expected that air has a penetration effect approximately 55 times greater than water in the ground.

Focusing on this point, the present inventors applied compressed air and pressurized water to J1! in hopes of injecting grout over a wide range of ground particles. ! After repeated experiments in which grouting material was injected by blowing into the board, it was found that the former injected grouting material over a wider area than the latter.
I was able to do that. The reason for this is that in addition to the difference in viscosity coefficient between air and water, in the latter case, even when the gaps between ground particles are enlarged, water still exists in the gaps, and when grouting material is injected, water still exists in the gaps. This is thought to be because water exerts resistance on the flow of the grout material.

In addition, the inventors repeated experiments in which grout was injected by blowing dry compressed air and non-dry compressed air into the ground, and found that the former injected grout over a wider area than the latter. was completed. The cause is
This is thought to be because the adhering water adhering to the soil particles is vaporized by the dry compressed air, forming finer dried air channels there than the latter.

A plurality of second holes are bored in a position separated from the inlet hole, and gas and liquid are sucked through the second holes. However, when we conducted an experiment in which dry compressed air was blown into the hole and then grout was blown in, the results showed that the grout could be injected in a shorter time than when gas and liquid were not sucked through the second hole.
I was able to do that.

This is thought to be because the gas and liquid are sucked through the second hole, thereby creating a negative pressure around the first hole into which compressed air and grout material are blown.

(Example) An embodiment shown in one drawing will be described below.

The grouting device, generally indicated by the reference numeral 10 in FIG.
first and second pipes 12,14, a compressed air generation mechanism 16, a dryer 18 that dries the compressed air, and a guide pipe 20 that guides the dried compressed air to the first pipe 12; A supply mechanism 22 that supplies grout to the first pipe 12 via the guide pipe, and a second pipe 14.
and a suction mechanism 24 that suctions gas and liquid through the suction mechanism 24 .

The first and second pipes 12.14 have a plurality of slits 26.28 at their tips. Each pipe 12 .
2 is connected to the guide pipe 20, and the second pipe 14 is connected to the suction mechanism 24.

The first and second pipes 12.14 are maintained vertically by a cover concrete 40 placed on the top surface of the ground 30, and by a sealing material 42.44 such as a puff force placed at the top of the hole 32.34. Airtightness between the pipes 12, 14 and the ground 30 is maintained.

The compressed air generation mechanism 16 includes a compressor 46 and a storage tank 4 that stores the compressed air generated by the compressor.
8, a water tank 50, and an air tank 5z. The storage tank 48 is connected to the compressor 46 via a valve 54, to the top of a water tank 50 via a valve 56, and to the top of an air tank 52 via a valve 58, respectively. The water tank 50 and the air tank 52 are connected to each other at the bottom via a valve 60 and at the top to the inlet of the dryer 18 via a valve 62, 64 and a pipe 66.

Each tank 48.50.52 has a pressure gauge 68.70.72
Equipped with. The water storage tank 50 includes a water meter 73 and a hopper 74.
and a valve 76. The internal pressure of the air tank 52 is 10
~30Kg/cm2, preferably 20Kg/cm2.

The generation mechanism 16 stores compressed air generated by the compressor 46 in a tank 48, supplies water from a hopper 74 to a tank 50 via a valve 76, and supplies water from the tank 48 to the tank 50.
．． supplying compressed air to tank 50.
After maintaining the pressure of 54 at a predetermined ICI, close all valves except valve 60 and wait.

Dried Fj1ta is a known commercially available product,
For example, compressed air is cooled to about 1 to 2 degrees C.
Top 41 Ge 9 Mt.

The humidity of the compressed air supplied to the dryer 18 is determined by the generation mechanism 1.
6 generates compressed air using water, 60-80
%, and this is 20 to 40% in drying 41118
Dry to humidity. The lower the humidity of the compressed air sent from the dryer 18 to the guide pipe 20, the better.

The guide pipe 20 is connected at one end to the connector 36 and at the other end to the dryer 18 via a mixer 78 and a grout supply mechanism 22. A pressure gauge 80, a hygrometer 82, and a thermometer 84 are connected to the pipe 20.

The grout supply mechanism 22 is disposed downstream of the dryer 18 and includes a hopper 86, a valve 88, and a mechanism for intermittently discharging the grout material to the guide pipe 20 together with the compressed air discharged from the dryer 18. There is an intermittent ejector 90. The hopper 86 stores powdered grout material having an average particle size of 4 microns or less.

Examples of such grout materials include ultrafine cement, silica flour, and silica flour.

The intermittent ejector 90 receives grout material from the hopper 86 to prevent compressed air passing through the guide pipe 20 from flowing into the hopper 86 .

Then, the process of feeding into the guide pipe 20 is repeated.

The mixer 78 has a part of the guide pipe 20 made thick and a spiral blade 92 arranged inside the guide pipe 20 to form a spiral passage for the compressed air. The grout material is transported by compressed air from the intermittent ejector 90 to the mixer 78, where it passes through the mixer 78 and occasionally impinges on the vanes 92, thereby being uniformly distributed in the compressed air.

The suction mechanism 24 includes a suction pipe 9 connected to a connector 38.
4, and a suction pump 96, such as a vacuum pump, for sucking gas and liquid from the second pipe 14 through the suction pipe.
and a gas-liquid separator 98 that is disposed between the suction pump and the suction vibrator 94 and separates the sucked gas and liquid;
A Hugal pump 100 that sucks the liquid separated by the gas-liquid separator, a notch box 102 that measures the amount of liquid discharged from the Hugal pump, and the gas-liquid portion 84.
A pressure gauge 104 disposed at 198 and the suction pipe 9
and a pressure gauge 106 located at 4.

The first pipe 12 is connected to the dust collector 11'l12 via a pipe 108 and a valve 110.

When the grouting device 3110 operates, first, the suction mechanism 24 sucks liquid and gas in the ground 30, while compressed air in the tank 52 is supplied to the first pipe 12 via the valve 64, and from the slit 26 of the pipe. It is blown out into the ground 3o. As a result, the compressed air removes the interstitial water between the soil particles around the first hole 32, thereby forming an air passage through which gas can pass.

At this time, since the compressed air blown into the ground 30 is dried by the dryer, the water adhering to the soil particles is dried by the dry air, resulting in fine particles compared to the case where compressed air that does not dry is used. An airway is formed, and
Air tracts are formed over a wider area.

In addition, since the suction mechanism 24 sucks gas and liquid from the second hole 34 and maintains negative pressure around the first hole 32, the compression that is blown from the first hole 32 into the ground 3 degrees The air moves toward the second hole 34, and the air passageway can be formed over a wider area than in the case where the negative pressure around the first hole is not maintained. Therefore, if a plurality of second holes 34 are bored around the first hole 32 and compressed air is blown into the first hole 32 while sucking gas and liquid from the 6 second holes, the It is possible to form air passages over a wide area of the surrounding area.

The formation of the air passage means that, when the air passage is formed, the pressure in the first pipe 12 and the amount of compressed air to be blown in change rapidly. This can be learned by monitoring the flow of the river.

Next, the blowing of compressed air is continued, especially the 111 items, 99 yen of the 99 yen, and the grout material are pumped together with the compressed air through the first pipe 12 into the ground 3.
This causes the grout material to be injected together with compressed air into the ground 30 through the air channel.

At this time, since the grouting material is blown together with dry compressed air, the grouting material essentially functions like a gas and is therefore injected into a wider area of the ground 30 than a liquid grouting material.

Note that a gaseous grouting material may be used and injected into the air passage alone or together with a dried compressed gas. When a gaseous grout material is injected alone into the air passage, the air passage can be maintained with the grout.

When the entire air passage is filled with grout material, suction of gas and liquid by the suction mechanism 24 and blowing of compressed air and grout material into the first holes 32 are stopped. As a result, groundwater returns around the first hole 32, and the grout material injected into the ground 30 is mutually and/or attached to soil particles by the groundwater. The fact that all the air permeable passages in the pitted 10-hole 1 are filled with the eggplant grout material confirms that the grout material has reached the second hole 34, for example.
You can know by

In this case, until the grout reaches the second hole 34, the dust collector 112 is driven to remove the excess grout to prevent the entrance of the air passage from being blocked by the excess grout. .

The intermittent ejector 90 shown in FIGS. 2(A) and 2(B) includes a cylinder 114, a piston 116 disposed within the cylinder, a piston rod 118 connected to the piston, and a crank that reciprocates the piston 116. 120. The piston 116 has two openings 122, 124 spaced apart in the direction of its central axis. One opening 122
is in communication with the guide pipe 20, and the other opening 124 is in communication with the hopper 86. The piston 116 has a recess 126 in its longitudinally intermediate portion, and four seal rings 128 are arranged around its outer periphery.

In the intermittent ejector 90 shown in FIG. 2, when the piston 116 is reciprocated, the recesses 126 of the piston 116 alternately communicate with the openings 122 and 124, and the grout material is received from the hopper 86 into the recesses 126. Guide pipe 2
Repeat the process of supplying to o.

That is, when the piston retreats, the recess 126 communicates with the opening 124 and the grout material from the hopper 86 is received in the recess 126, as shown in FIG. 2(B). At this time, the opening 122 is closed by the seal ring 128. Furthermore, when the piston 11B moves forward, the recess 126 communicates with the opening 122, as shown in FIG. . At this time, the opening 124 is closed by the seal ring 128.

[Brief explanation of drawings]

FIG. 1 is a schematic view showing an embodiment of the grouting device of the present invention, and FIGS. 2(A) and 2(B) are sectional views for explaining the operation of the intermittent ejector. 12, first pipe, 14: second pipe, 16: compressed air generation mechanism, 18: dryer, 20 guide pipe, 22 nigeroud material supply mechanism, 24: suction mechanism, 3o: ground, 32: 1st hole, 34: 2nd hole. 86: Hopper, 9o: Intermittent discharge mechanism, 114 Niji cylinder, 116: Piston.

Claims (15)

[Claims] (1) Drill a hole in the ground, blow compressed gas into the hole after drying to form an air passage around the hole, and then blow grout into the hole while maintaining the air passage, A method of grouting, including grouting. (2) The method according to claim 1, wherein the air passageway is maintained by continuing to blow the dried compressed gas into the hole. (3) Claim No. 2, wherein the grout material is blown into the hole and injected into the air passage while maintaining the air passage by blowing the grout material into the hole together with the dried compressed gas. The method described in section. (4) The method according to claim (1), (2) or (3), wherein the grout material is either gas or powder. (5) The method according to claim (1), wherein the grouting material is injected into the air passage while maintaining the air passage by blowing a gaseous grout into the first hole. (6) Drilling first and second holes in the ground, sucking gas and liquid from the second holes, and drying the compressed gas and then blowing it into the first hole to create a space around the first hole. A method of grouting, comprising: forming an airway in the first hole, and then blowing a grout material into the first hole while maintaining the airway and injecting the grout into the airway. (7) The air passageway is maintained by continuing to blow the dried compressed gas into the first hole and suck the gas and liquid from the second hole. The method described in (6). (8) A blowout pipe inserted into a hole drilled in the ground, a compressed gas generation mechanism, a dryer that dries the compressed gas, and a guide pipe that guides the compressed gas that has passed through the dryer to the blowout pipe. and a mechanism for supplying grout material to the spout pipe via the guide pipe. (9) The grout supply mechanism includes a hopper that stores powder and an intermittent discharger that intermittently discharges the grout stored in the hopper to the guide pipe. 8) The device described in section 8). (10) The intermittent ejector includes a cylinder having a first opening that communicates with the guide pipe and a second opening that communicates with the hopper; The device according to claim 9, comprising a piston having recesses alternately communicating with openings of the piston, and a drive source for moving the piston. (11) The first and second openings are separated in the direction of the central axis of the cylinder.
). (12) The guide pipe includes a mixer that evenly distributes the powder mixed in the high-pressure gas.
). (13) The blowout pipe is connected to a dust collector.
An apparatus according to claim (8), (9), (10), (11) or (12). (14) first and second pipes inserted into first and second holes drilled in the ground, respectively, and a compressed gas generation mechanism;
a dryer that dries the compressed gas; a guide pipe that guides the compressed gas that has passed through the dryer to the first pipe; a mechanism that supplies grout material to the first hole through the guide pipe; a suction mechanism that suctions gas and liquid from the second pipe. (15) The suction mechanism includes a suction pipe connected to the second pipe, a suction pump that suctions gas and liquid from the second pipe via the suction pipe, and the suction pump and the suction pipe. 15. The apparatus according to claim 14, further comprising a separator disposed between and separating the sucked gas and liquid into gas and liquid.