JPS58204213A - Injection of silicate-based grout for stabilization of ground into ground - Google Patents

Abstract

PURPOSE:To vary the gelling time of a grout to a quick or slow-setting type according to the conditions of the ground in an instantaneous manner by a method in which water is supplied to the second mixer while the grout is injected into the ground in such a way as to vary the concentration of carbonic acid water in the mixer. CONSTITUTION:A high pressure of carbon dioside gas and water are supplied to the first mixer a carbon dioxide gas tank 1 (liquefied carbon dioxide gas bomb usually) and a water storage tank 8 to produce a carbonic acid water. The carbonic acid water produced in the first mixer 6 and a sodium silicate aqueous solution from a sodium silicate aqueous solution storage tank 13 are supplied to the second mixer 19, where the carbonic acid water and the sodium silicate aqueous solution are mixed together to become a grout. The grout is injected into the ground 21. While the grout is injected, water is supplied from the water storage tank 16 to the second mixer 19 to vary the concentration of carbonic acid water in the mixer 19, whereby permitting the gelling time of the grout to be adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for injecting silicate-based grout into the ground for stabilizing the ground using sodium silicate as the main ingredient and carbon dioxide as the hardening agent. To provide a method that can immediately change the gel time of grout to any length or shortness corresponding to ground conditions while continuously injecting grout into the ground.

Conventionally, various methods have been proposed for injecting grout for ground stabilization that combines sodium silicate and carbon dioxide, and this is a representative method.

For example, carbon dioxide and water at elevated pressure are supplied to a first mixer of a sealed pressure-resistant structure, which is equipped with appropriate fluid mixing equipment therein, and carbon dioxide and water are added under pressure by the feedstock in the mixer. produce water.

The carbonated water thus obtained is then fed to a second mixer while maintaining the pressure at which it was produced, and mixed in the mixer with a stoichiometric amount or more of an aqueous sodium silicate solution. A method is known in which grout is injected into the ground.

In this method, the adjustment of the grout gel time is
This is done by increasing or decreasing the concentration of the carbonated water produced in the first mixer; this method involves a system scale from the time carbon dioxide is supplied to the first mixer until the grout is injected into the ground. Depending on the method, it may take more or less time, so depending on the method, during the grout injection into the ground,
It is not possible to instantly change the gel time to match the ground conditions.

The present invention relates to a method for injecting silicate-based grout into the ground for stabilizing the ground using carbon dioxide as a hardening agent, in which such drawbacks have been corrected. Carbon dioxide and water are supplied at elevated pressure, carbonated water is produced in the mixer, and the resulting carbonated water is simultaneously supplied to one inlet of the second mixer and simultaneously to the other inlet. A method in which a sodium silicate aqueous solution is supplied, the two are combined and mixed in the mixer, and the grout thus obtained is injected into the ground.

A method for injecting silicate-based grout into ground for ground stabilization, characterized by supplying water to a second mixer during injecting grout into the ground. "It is in.

FIG. 1 is a flow sheet showing one embodiment of the present invention. In the present invention, carbon dioxide is used as a hardening agent for grout, and both carbon dioxide gas and liquefied carbon dioxide gas can be used as a carbon dioxide source, but below, one embodiment in which carbon dioxide gas is used as a carbon dioxide source will be described. Let me explain.

Carbon dioxide gas and water under increased pressure are supplied from the carbon dioxide storage tank 1 (usually a liquefied carbon dioxide cylinder) and the water storage tank 8 to the first mixer 60 input section.

The carbon dioxide gas storage tank 1 is immersed in a hot water tank 2 and heated as necessary to prevent the decrease in pressure inside the tank and the outflow of carbon dioxide gas that are observed when a large amount of carbon dioxide gas flows out from the storage tank 1. It is possible to prevent the amount from decreasing and the temperature inside the tank from decreasing.

By opening the flow control valve (pressure reducing valve) 3 and causing the carbon dioxide gas to flow out from the carbon dioxide gas storage tank 1, the accompanying droplets can be vaporized by passing through the evaporator 4.

Reference numeral 5 denotes a flow rate adjustment device that can keep the flow rate of carbon dioxide gas supplied to the first mixer 6 constant.

Note that in the present invention, liquefied carbon dioxide gas can also be used as a carbon dioxide source;

Normally, it is desirable to use a liquefied carbon dioxide gas cylinder in which a siphon is inserted, and to take out the liquefied carbon dioxide gas with a pump and supply it to the first mixer 6.

The No. 10 mixer 6 used in the present invention is provided with a carbon dioxide supply port, a water supply port, and a carbonated water discharge port at appropriate portions thereof, and has a good contact mixing of gas-liquid or liquid-liquid inside. It is a vertical or horizontal container with a sealed pressure-resistant structure and is equipped with any device such as a stirrer, a jammer plate, etc.

In the KJd diagram inside the first mixer 6, a propeller-type stirrer with stirring blades is provided, but in the present invention.

The stirring blades are not limited to these shapes, but include turbine type, fan turbine type, curved blade fan turbine type,
A Faudler-type, pullmargin-type, or other type of stirrer equipped with an arbitrary stirring blade can be used.

Carbon dioxide can be supplied to the first mixer 6 not only from the top of the mixer 6, but also from the bottom and blown up to the top, or by inserting a nozzle into the aqueous phase in the mixer 6. Then, carbon dioxide may be bubbled through the nozzle.

On the other hand, as a method of supplying water, it is preferable to drop the water as minute droplets from the upper part of the first mixer 6 using a spray nozzle because it can improve the contact efficiency with C(h).

In addition, the first mixer 6 is a mixer in which a stationary fluid stirring element is provided.

A so-called line mixer (pipe mixer) is also suitably used, but whatever type of mixer is used,
It is desirable to use a mixer equipped with a mixing stand device with good stirring efficiency that can mix the supplied carbon dioxide gas and water in as short a time as possible.

The carbon dioxide gas and water supplied to the first mixer 6 are mixed in the mixer to produce carbonated water.

In the present invention, the carbonated water produced in the first mixer 6 may be in a saturated concentration state, that is, the Cot concentration has reached saturation, but if the CO2 concentration of the carbonated water is in such a state In this case, if the pressure of the carbonated water decreases in the subsequent process, carbon dioxide gas may be generated from the carbonated water and cause trouble. It is desirable that the concentration be in an unsaturated concentration state, that is, a state in which the CO2 concentration has not yet reached saturation at the pressure at that time.

Carbonated water of any concentration can be produced in the first mixer 6 by appropriately adjusting the pressure in the first mixer 6. Flow rate) can be arbitrarily changed by appropriately adjusting the control valve 11 or appropriately adjusting the supply pressures of water and carbon dioxide gas.

Next, the carbonated water thus produced in the first mixer 6 is supplied to one inlet of the second mixer 19, and at the same time, the sodium silicate aqueous solution is supplied from the storage tank 13 to the other inlet.

As the sodium silicate used in the present invention, JIS No. 3 sodium silicate, which has been conventionally used for stabilizing the ground, is usually suitably used.
It is also possible to use a number from 3 or higher, which is higher than No. 3, to about 5.5.

During construction, these sodium silicate materials are diluted with water to form an aqueous solution with an appropriate concentration suitable for ground stabilization.

In the present invention, the concentration of the raw material sodium silicate in the sodium silicate aqueous solution charged to the sodium silicate aqueous solution storage tank 13 is usually 20
It is preferable to set the amount to 100% by volume, especially 25 to 60% by volume.

The second mixer 19 is also used for injecting grout into the ground, and is a hollow double pipe with a mixing chamber provided at its outlet, which is commonly used in the production and injecting of this type of grout into the ground. Ordinarily, a general static pipe mixer having a fluid temperature heating element provided therein is preferably used.

At the outlet of the second mixer 19, there is usually installed a pressure holding valve 20 that can keep the pressure inside the mixer constant.

Conventionally, this type of pressure holding valve has various structures such as spring type, hydraulic type, electronic type, and pneumatic type, but any type can be used in the present invention.

In the present invention, the pressure in the second mixer 19 is maintained at approximately the same pressure as the carbonated water and the sodium silicate aqueous solution supplied into the mixer 19 by the pressure holding valve 20.

The carbonated water and the sodium silicate aqueous solution supplied into the second mixer 19 are mixed in the mixer to produce grout.

The grout thus obtained is then directly injected into the ground; however, in the present invention, water is supplied to the second mixer 19 while the grout is being injected into the ground.

That is, in one aspect of the present invention, water is supplied to the second mixer 19 during the grout injection into the ground to change the concentration of carbonated water in the mixer, thereby adjusting the gel time of the grout. therefore.

In the present invention, when the gel time of the grout is arbitrarily adjusted by the supply water from a time almost instantaneous setting to several hours, the CO2 concentration of the carbonated water produced in the first mixer 6 is When water is not supplied to the second mixer 19, it is necessary to adjust the concentration to such a level that the aqueous sodium silicate solution is instantaneously condensed in the mixer 19Ft.

On the other hand, if it is not necessary to adjust the gel time of the grout over such a wide range of time, for example, when adjusting the gel time of the grout over a period of several minutes to several tens of minutes, the carbonated water produced in the first mixer 6 The C02 concentration may be lower than the above, and if water is not supplied to the second mixer 19, the concentration may be such that the aqueous sodium silicate solution gels within a few minutes in the second mixer 19.

At this time, the water for gel time adjustment may be supplied directly to the inlet of the second mixed book, but the water for adjusting the gel time may be supplied directly to the inlet of the second mixing volume, or the water for adjusting the gel time may be supplied from the carbonated water and the sodium silicate storage tank 13 supplied from the first mixer 6 to the second mixer 19. The sodium silicate aqueous solution may be combined with one or both of the sodium silicate aqueous solutions supplied to the second mixer 19 and then supplied to the second mixer 19 .

In the present invention, the water supplied to the second mixer 19 is usually almost instantaneously mixed with other components in the mixer and then injected into the ground.

Therefore, according to the present invention, the gel time of grout can be immediately (almost instantaneously) changed to any length or short value that corresponds to the ground conditions while the grout is being poured into the ground.

This made it possible to cope with complex soil conditions. Fine-grained ground stabilization work can be carried out.

Furthermore, according to the present invention, a method of simultaneously injecting a plurality of grouts each having a different gel time into the ground, that is, a composite injection method is called Xuneng.

To explain this with drawings, FIG. 2 is a flow sheet showing one embodiment of the composite injection method according to the present invention.

In FIG. 2, numerals 19, 22 and 23 are second mixers (also serving as grout injection pipes) installed in the ground with different soil conditions.

During construction, the first mixer 6.
Carbonated water, sodium silicate aqueous solution, and water for gel time adjustment are supplied simultaneously to a sodium silicate aqueous solution storage tank 13 and a water storage tank 16, respectively.

At this time, by appropriately changing the amount of water for gel time adjustment supplied to each mixer, grout having a gel time suitable for each soil condition is manufactured in each mixer and is injected into the ground.

According to this composite injection method, complex ground with various soil conditions can be easily stabilized with a single construction.

9 In carrying out the present invention, for example, if the gel time is to be drastically changed during grout injection into the ground,
If a method is adopted in which only the amount of water supplied is increased or decreased while keeping the amount of carbonated water and sodium silicate aqueous solution supplied to the second mixer constant, the concentration of sodium silicate in the grout will fluctuate widely due to the increase or decrease in the amount of water. Sometimes.

If such changes in the concentration of sodium silicate are undesirable, the supply of carbonated water can also be changed according to the amount of water supplied, and no matter how the gel time of the grout is changed, the amount of water supplied and the amount of carbonated water It is desirable to keep the total amount of supply constant.

In addition, in the present invention, it is desirable that the amount of carbon dioxide gas used in the production of grout be less than the stoichiometric amount relative to sodium silicate, thereby preventing the generation of carbon dioxide gas from the grout injected into the ground. I can do it.

Next, the present invention will be explained in more detail with reference to Examples.

Example: A paddle type stirring blade (length x width - 130'IIIX
Water at a temperature of 18 tr was supplied from the upper part of the first mixer with a sealed pressure-resistant structure equipped with 50 fil) at a rate of 3.6 A 7 minutes, and at the same time liquefied carbon dioxide gas was supplied at a rate of 0.10 s k.
y/min and mixed both in the mixer to produce carbonated water. At this time, the pressure in the first mixer was maintained at 23 kg/cl by the feedstock. Next, the obtained carbonated water is transferred to one inlet of a second mixer (static pipe mixer) having a diameter of 21 stL and a length of 150 baskets, which is equipped with a pressure-holding valve at the tip and six liquid mixing elements inside. part 3.6
．． At the same time, a sodium silicate aqueous solution with a ratio of JIS No. A silicate powder: water - 1:1 (volume) is continuously supplied to the other inlet at a rate of 3.6 e/min. provided.

At this time, the pressure inside the second mixer is 25 to 30 kt/a.
The spring of the pressure retention valve was adjusted to maintain /(.

The raw materials fed into the second mixer are mixed almost instantaneously in the mixer to produce grout.

It was ejected from the exit. This grout was a homogeneous solution, no CO2 gas generation was observed, and the gel time was 3 seconds.

Next, while maintaining the above operating conditions, water + 7.2p was supplied to the second mixer at a rate of 7 minutes, and the grout with a gel time of 30 seconds was immediately discharged from the outlet of the mixer.

Next, while maintaining this operating state, the amount of water supplied to the second mixer is increased to 14.4. -e/min, a grout with a gel time of 2 minutes and 20 seconds was immediately obtained from the outlet of the mixer.

[Brief explanation of the drawing]

FIGS. 1 and 2 are flow sheets showing one embodiment of the present invention. Symbols 1 Carbon dioxide storage tank 2 Hot water tank 3 Flow rate adjustment valve (pressure reducing valve) 4 Evaporator 5 Flow rate adjustment device 6 First mixer 7 Stirring drive motor 8 Water storage tank 9 Flow rate adjustment valve 10 Pump 11 Pressure (flow rate) adjustment Valve 15-12 Pump 13 Sodium silicate aqueous solution storage tank 14 Flow rate adjustment valve 15 Pump 16 Water storage tank 17 Flow rate adjustment valve 18 Pump 19 Second mixer (Part 1) 20 Pressure holding valve 20' Spring 21 Ground 22 Second mixer ( Part 2) 23 Second mixer (Part 3) 24 Flow rate control valve 25 Flow rate control valve 26 Flow rate control valve Patent applicant Nitto Chemical Industry Co., Ltd. 16- Procedural amendment (voluntary) July 2, 1980 Patent Office Mr. Kazuo Wakasugi, Commissioner, 1. Indication of the case, Patent Application No. 87340 of 1987. 2. Name of the invention, Method for injecting silicate grout into the ground for ground stabilization. 3. Person making the amendment: 5-chome Marunouchi, Chiyoda-ku, Tokyo, 100. number 1 46
The list of attached documents column of the application to be amended, column 5 of the detailed description of the invention in the specification, contents of the amendment (1) The column of list of attached documents of the application will be amended as follows. (1) One copy of the specification (2) (Two copies of drawings) (3) (One copy of the application) (2) The "concentration" stated on page 10, line 11 of the specification is r
"high concentration". (3) “As stated on page 10, lines 12-13 of the specification.
Correct "wide range" to "wide range". (4) “In this case” stated in the bottom line of page 10 of the specification
shall be amended to read "in carrying out the present invention". (5) "Sodium silicate" described on page 11, line 3 of the specification
is corrected as "sodium silicate aqueous solution". (6) Insert the following sentence between the 5th and 6th lines from the bottom on page 11 of the specification. ``In contrast, in the past, the gel time of grout was adjusted by varying the concentration of carbonated water in the first mixer 6; Since it takes more or less time from supplying carbon dioxide to the mixer until the grout is injected into the ground, it is not possible to change the gel time of the grout almost instantaneously as in the present invention. (7) Change ``change the amount of water supplied'' to ``inversely proportional to the amount of water supplied'' on page 13 of the specification, lines 5-6. and then change the amount of carbonated water supplied. Above 3-65-

Claims (3)

[Claims] (1) Supply carbon dioxide and water under increased pressure to a first mixer, produce carbonated water in the mixer, and then transfer the obtained carbonated water to one inlet of the second mixer. In this method, a sodium silicate aqueous solution is simultaneously supplied to the other inlet, the two are combined and mixed in the mixer, and the grout thus obtained is injected into the ground. A method for injecting silicate-based grout for ground stabilization into the ground, characterized by supplying water to a second mixer. (2) Claim No. 2 in which the carbon dioxide is carbon dioxide gas (
1) Method for injecting silicate grout for ground stabilization into the ground as described in section 1). (3) A ground corporation method for producing silicate-based grout for ground stabilization according to claim (1), wherein the carbon dioxide is liquefied carbon dioxide gas.