KR20210096968A - Compositions of back filling cement containing high performance stablizer to extend pot stability and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a composition for injection of thixotropic backfill and a method for manufacturing the same. Specifically, the composition includes: liquid-A containing bentonite, plastic slag cement, a stabilizer and water; and liquid-B containing sodium silicate.

Description

A cement composition for backfilling comprising a high-performance stabilizer for extending pot life, and a method for manufacturing the same.

The present invention relates to a stabilizer composition that increases the pot life of the backfill material used in the process of backfilling the cavity of the back surface of the underground structure generated during underground tunnel construction by a mechanical tunnel method or the like.

Two-component injection is widely adopted for backfilling materials used to backfill the over-cut backside or fill the cavity of underground structures after lining assembly in the mechanical tunnel excavation process. In general, for two-component injection, a plastic cement solution (solution A) is prepared and pumped through a transfer pipe to meet with sodium silicate solution (solution B) to form a gel. Swellable bentonite is used in order to prevent this because cement or plastic cement is sedimented and separated and is deposited in the pipe to cause clogging. In this case, the bentonite used must be of high performance to prevent settling, so that the pot life can be extended.

In addition, a stabilizer is used that can prevent the pot life from being shortened due to the loss of fluidity as the cement component of solution A is cured in water, but the stabilizing performance is weak. Immediately after injection, the inside of the pipe is washed with water. Such work may cause environmental pollution due to loss of manpower, delay in work, and generation of cement-contaminated wastewater. In addition, when the backfill co-injection design specification was followed, the backfilling defect occurred frequently due to the clogging of the co-injection equipment during the construction process.

An object of the present invention is to solve the above problems and other problems, and an object of the present invention is to provide a composition for backfilling cement containing a stabilizer and a method for manufacturing the same.

In addition, when the cement milk liquid, which is liquid A, remains in the pressure delivery pipe, the purpose of this is to prevent the cement component having a larger specific gravity than water from sinking or hardening quickly to block the pressure delivery pipe.

In addition, according to the material separation of the A solution, it meets the silicic acid solution, which is the B solution, and reacts in a non-uniform state in the process of gelation.

However, these problems are exemplary, and the scope of the present invention is not limited thereto.

According to one aspect of the present invention, it provides a composition for backfill injection, which comprises a liquid A containing bentonite, a plastic slag cement, a stabilizer and water, and a liquid B containing sodium silicate.

According to an embodiment of the present invention, the composition may be comprised of 80 wt% to 95 wt% of solution A, and 5 wt% to 20 wt% of solution B.

According to an embodiment of the present invention, the liquid A is 20wt% to 50wt% of the plasticized slag cement based on the total weight of the liquid A, the stabilizer is 0.1wt% to 0.5wt%, and the water is 50wt% to 80 wt%, and the bentonite may be included in an amount of 3 wt% to 15 wt% compared to the plasticized slag cement.

According to an embodiment of the present invention, the plasticized slag cement includes Portland cement, slag powder and slaked lime, and the Portland cement is 45 wt% to 75 wt%, based on the total weight of the plasticized slag cement. The slag powder may be included in an amount of 20 wt% to 40 wt%, and the slaked lime in an amount of 5 wt% to 15 wt%.

According to an embodiment of the present invention, the stabilizer may include sucrose, citrate, and water, and the sucrose may be included in an amount of 5 wt% to 30 wt% based on the total weight of the stabilizer.

According to an embodiment of the present invention, the citrate may be included in an amount of 50 to 150 parts by weight based on 100 parts by weight of the sucrose.

According to an embodiment of the present invention, the degree of swelling of the bentonite may be 15 to 40.

According to an embodiment of the present invention, the bleeding rate (material separation rate) of the liquid A may be 5% or less.

According to an embodiment of the present invention, the pot life of the liquid A may be 72 hours or more.

According to another aspect of the present invention, as a method for producing a composition for backfill injection, the step of preparing a solution A including bentonite, plasticized slag cement, a stabilizer and water, and pumping the solution A to the backfilling process It provides a method for preparing a composition for injection of a plastic phase backfill comprising; mixing the liquid B containing sodium silicate before the following.

According to an embodiment of the present invention, the step of preparing the liquid A may include the step of adding bentonite to water, the step of adding a stabilizer, and the step of adding the plasticized slag cement.

According to an embodiment of the present invention, the step of adding bentonite to water may include adding bentonite while stirring water, and aging for 5 minutes or more when the input is completed.

The effects of the composition for injection of plastic backfill according to the present invention and a method for preparing the same are as follows.

According to at least one of the embodiments of the present invention, there is an effect of providing a high-performance stabilizer that extends the pot life of the A solution.

In addition, when the cement milk liquid, which is liquid A, remains in the pressure delivery pipe, the cement component having a greater specific gravity than water sinks or hardens quickly, thereby preventing the pressure delivery pipe from being blocked.

In addition, there is an effect of preventing the non-uniform backfilling by reacting in a non-uniform state in the process of gelation by meeting with the silicic acid solution, which is solution B, according to the material separation of solution A.

Further scope of applicability of the present invention will become apparent from the following detailed description. However, it should be understood that the detailed description and specific embodiments such as the preferred embodiments of the present invention are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention may be clearly understood by those skilled in the art.

1 is an image observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Example 1.
2 to 6 are images of observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Comparative Examples 1 to 5.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. These examples are merely illustrative to explain the present invention in more detail, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not limited by these examples. will be.

Further, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and in case of conflict, this specification, including definitions description will take precedence.

In order to clearly explain the invention proposed in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification. And, when a part "includes" a component, it means that other components may be further included, rather than excluding other components, unless otherwise stated. In addition, as described in the specification, “subordinate” refers to one unit or block that performs a specific function.

In each step, the identification number (first, second, etc.) is used for convenience of description, and the identification number does not describe the order of each step, and each step does not clearly describe a specific order in context. It may be performed differently from the order specified above.

That is, each step may be performed in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

In addition, in the present invention, the term “plastic phase” means an intermediate region between a liquid and a solid that is self-supporting due to no magnetic fluidity when stationary, but fluidizes when pressurized.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily practice the present invention.

According to an embodiment of the present invention, the composition for backfill injection is characterized in that it largely comprises a liquid A and a liquid B.

The liquid A is characterized in that the main ingredient is cement as a strength developer.

Accordingly, as an example, the composition for backfill injection, which is the liquid A, is characterized in that it comprises plasticized slag cement, a stabilizer, bentonite, and water.

The plasticized slag cement is a main composition for backfilling the plasticized phase, and the amount of the plasticized slag cement is preferably 20wt% to 35wt% based on the total weight of the liquid A.

At this time, the plasticized slag cement is prepared from Falkland cement, slag powder and slaked lime as main components, and it is characterized in that it contains a specific content in order to give the plasticity state and strength of the plasticized backfill composition.

First, the Portland cement may be included in an amount of 45 wt% to 75 wt% based on the total weight of the plasticized slag cement, and the slag powder may be included in an amount of 20 wt% to 40 wt%. At this time, if the content of the portlant cement is less than 45wt%, the initial strength may be lowered, and if it exceeds 75wt%, the function may be weakened by leaching.

In addition, when the content of the slag powder is less than 20wt%, the strength may be lowered in the long term, and if it is contained in excess of 40wt%, the initial strength may be lowered.

In addition, the slaked lime is added to give plasticity to the plasticized slag cement and to shorten the gel time (gel time), and the slaked lime is preferably included in an amount of 5 wt% to 15 wt%. At this time, when the content of the slaked lime is less than 5 wt%, the gelation time may be long.

As another example, the liquid A may be formed by adding only Portland cement instead of the plastic slag cement. That is, the liquid A containing portlant cement, a stabilizer, bentonite and water may be prepared without preparing the plasticized slag cement containing the portlant cement.

The stabilizer is added to increase pot life, and the stabilizer is characterized in that it comprises 0.1 wt% to 0.5 wt% based on the total weight of the solution A. Specifically, when the content of the stabilizer is 0.1wt% or less, the pot life may be reduced, and when it is included in 0.5wt% or more, the strength may be reduced.

At this time, the stabilizer is characterized in that it contains sucrose, citrate, and water. By adding the sucrose and the citrate, the pot life can be controlled. It acts as a deterrent and increases the pot life.

Furthermore, the sucrose is contained in an amount of 5 wt% to 30 wt% based on the total weight of the stabilizer, the citrate is contained in an amount of 10 wt% to 35 wt%, and the remainder is characterized in that water is used as the dissolved water. Specifically, the citrate is preferably included in an amount of 50 to 150 parts by weight based on 100 parts by weight of the sucrose.

At this time, if the sucrose content is less than 5 wt%, pot life may be shortened, if it exceeds 30 wt% or if the citrate is less than 10 wt%, material separation may occur, and if it exceeds 35 wt%, strength may be reduced .

The water is to include fresh water, the water is characterized in that it comprises 30wt% to 80wt% based on the total weight of the liquid A.

Specifically, when the content of the water is less than 30wt%, it is difficult to dissolve the stabilizer component of the powder, and when it is contained in excess of 80wt%, the concentration of the stabilizer is low and the total solid content is small, so the pot life can be shortened.

The bentonite is characterized in that it is added to increase the pot life of the liquid A, and the bentonite is preferably included in an amount of 3 wt% to 15 wt% compared to the plasticized slag cement.

At this time, when the content of the bentonite is 3 wt% or less, the bleeding rate (material separation rate) is high and the visible time can be shortened.

In addition, the bentonite has a degree of swelling, and the degree of swelling of the bentonite is preferably 15 to 40. At this time, when the swelling degree of the bentonite is 15 or less, the bleeding rate (material separation rate) is high and the visible time may be shortened.

The liquid B is characterized in that it contains sodium silicate as a curing accelerator.

Specifically, the B solution is a curing agent for rapidly curing the A solution into a plastic state, and in the present invention, it refers to a material used to express the strength of the liquid or gel mixed solution when the plastic phase is backfilled. As such, the sodium silicate (sodium silicate) is characterized in that it includes sodium silicate No. 1, No. 2 and No. 3 shown in the KS standard (KS M 1415).

Furthermore, the liquid A is included in 80 wt% to 95 wt%, and the liquid B is characterized in that it is included in 5 wt% to 20 wt%. At this time, if the ratio of solution A is lower than 80%, the long-term strength is weak, and if it is higher than 95%, the initial strength is weak.

In addition, if the ratio of the B solution exceeds 20%, the gel (GEL) time becomes longer, and if it is less than 5%, the gel cannot be formed.

According to an embodiment of the present invention, in order to prepare the composition for injection of the plastic backfill, the steps of preparing a solution A including bentonite, a plastic slag cement, a stabilizer and water, and the pressure feeding of the A solution to backfill It characterized in that it comprises the step of mixing the B solution containing sodium silicate before proceeding.

In detail, the step of preparing the liquid A includes the step of adding bentonite to water, the step of adding the stabilizer, and the step of adding the plasticized slag cement.

First, the step of adding bentonite to the water is characterized in that the bentonite is prepared by adding the bentonite while stirring the water.

Specifically, after preparing the mixed solution containing the bentonite, it is characterized in that it is aged so that the bentonite in the mixed solution can be sufficiently swollen.

At this time, it is preferable to stir for a certain period of time for aging in order to ripen the mixture, and it is preferable that the aging proceeds for 3 minutes or more. In detail, it is preferable to aging for 1 hour or more, and when the aging time is less than 3 minutes, the bentonite may not swell sufficiently.

The step of adding the stabilizer and the step of adding the plasticized slag cement are characterized in that the bentonite mixture is aged and sufficiently swollen and then added.

At this time, when the bentonite mixture is added before it is sufficiently swollen, when a stabilizer and plastic cement are added, additional swelling is difficult due to the added stabilizer and cement component, which may cause material separation. Accordingly, it is preferable to sufficiently swell the bentonite in order to prepare the solution A, and then add a stabilizer and plasticized slag cement.

Hereinafter, the present invention will be described in detail through Examples and Experimental Examples. However, the following Examples and Experimental Examples only illustrate the present invention, and the present invention is not limited by the following Examples and Experimental Examples.

Example 1.

After adding bentonite with a swelling degree of 35 while stirring water, the mixture was stirred for 10 minutes. Thereafter, a stabilizer solution containing 20% sucrose and 20% sodium citrate was added, and plasticized slag cement containing 70% portland cement, 20% slag fine powder, and 10% plasticizer was added to prepare solution A.

Comparative Example 1.

After adding bentonite having a swelling degree of 15 while stirring water, the mixture was stirred for 1 hour. Thereafter, liquid A was prepared by adding plasticized slag cement containing 100% of Portland cement.

Comparative Example 2.

It was prepared in the same manner as in Comparative Example 1 except for adding a stabilizer solution containing 20% sucrose and 20% sodium citrate.

Comparative Example 3.

It was prepared in the same manner as in Comparative Example 1, except that plasticized slag cement containing 70% Portland cement, 20% slag fine powder, and 10% plasticizer was added.

Comparative Example 4.

It was prepared in the same manner as in Comparative Example 1, except that a stabilizer solution containing 20% sucrose, 20% sodium citrate, and plasticized slag cement containing 70% Portland cement, 20% slag fine powder, and 10% plasticizer were added.

Comparative Example 5.

It was prepared in the same manner as in Comparative Example 1, except that bentonite having a swelling degree of 35 was added, and plasticized slag cement containing 70% portland cement, 20% slag fine powder, and 10% plasticizer was added.

Table 1 below shows in detail Example 1 and Comparative Examples 1 to 5.

composition Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 A liquid bentonite degree of swelling 35 15 15 15 15 35 input 20 kg 52.5 kg 52.5 kg 52.5 kg 52.5 kg 20 kg plasticine
slag
cement portland cement 70% 100% 100% 70% 70% 70% slag
powder 20% - - 20% 20% 20% slaked lime 10% - - 10% 10% 10% input 330kg 350 kg 350 kg 330kg 330kg 330kg stabilizator saccharose
(20%) 3 kg - 3 kg - 3 kg - citric acid
salt
(20%) water 810kg 750kg 750kg 810kg 810kg 810kg 810kg B liquid sodium silicate solution
(Soda Silicate No. 3) 110 kg 138 kg 138 kg 110 kg 110 kg 110 kg

Measurement example 1 . Bleeding rate measurement method.

This was carried out under laboratory conditions when inspecting the material for on-site delivery. Prepare the test solution by pouring 1,000 ml of solution A prepared in the order of water, special bento, stabilizer, and plasticized slag cement into a 1,000 ml measuring cylinder so that no air enters. . Then, after curing for 3 hours, the material is bleed and the volume of the separated water is measured. At this time, the bleeding rate was calculated as (volume value of water/volume of measuring cylinder (1,000ml))*100.

Measurement example 2. How to measure pot life.

The test solution prepared to measure the bleeding rate is left at 20° C. for 3 days, and when the measuring cylinder is tilted, it should have fluidity in which all of the solution A in the measuring cylinder flows out.

Measurement example 3. How to measure the plastic state retention time

After measuring the gelation time, after 5 minutes, a hole with a diameter of 2 cm was made in the bottom edge of the plastic bag, squeezed the plastic bag with both hands, and discharged.

1 is an image observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Example 1.

Figure 1 (a) is an image observing the state of the liquid A after measuring the bleeding rate, it can be confirmed that the volume of the separated water is very small. Also, it can be seen that the bleeding rate calculated according to the measured value is very low at 2.5%.

Figure 1 (b) is an image observing the state of the liquid A according to the pot life measurement, it can be confirmed that it flows without clumping, and it can be confirmed that the pot life is maintained for more than 72 hours.

Figure 1(C) is an image of observing the state of the plastic phase backfill composition according to the plastic state maintenance time after adding the liquid B, and it was confirmed that the phenomenon of breakage and crumbling occurs after about 8 minutes.

2 is an image of observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Comparative Example 1.

Referring to Figure 2 (a), it can be confirmed that the sedimentation phenomenon is very severe, and thus it can be confirmed that the calculated bleeding rate is 17%.

In addition, referring to FIG. 2(b), it can be confirmed that the liquid A does not flow and is hardened, and it can be confirmed that the pot life is very short as 7 hours.

In addition, referring to FIG. 2(c), a phenomenon in which the flow is cut off and crumbles from the moment the plasticity state maintaining time is 1 minute or less is observed. Through this, it was confirmed that the plasticization state maintenance time was very short.

3 is an image of observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Comparative Example 2.

Referring to Figure 3 (a), similar to Comparative Example 1, it can be confirmed that the sedimentation phenomenon is very severe, and thus it can be confirmed that the bleeding rate is 16%.

In addition, referring to Figure 3 (b), it can be seen that the liquid A is partially solidified, the pot life is 42 hours, compared to Comparative Example 1, the pot life of Comparative Example 2 with the addition of the stabilizing solution is longer, but Compared to Example 1, it can be seen that the pot life is shorter.

In addition, referring to FIG. 3(c), the plasticized state holding time is less than 1 minute, and as in Comparative Example 1, the flow is cut off and crumbling from the moment of weaving, and it can be confirmed that the plasticized state holding time is very short.

4 is an image of observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Comparative Example 3.

Referring to Fig. 4 (a), it can be confirmed that the sedimentation phenomenon is very severe, and it can be confirmed that the bleeding rate is 17%.

In addition, referring to FIG. 4(b), it can be confirmed that the liquid A has no fluidity, and it can be confirmed that the measured pot life is very short as 8 hours.

In addition, referring to FIG. 4(c), the flow is partially cut off and crumbling is observed, and it can be confirmed that the plasticized state maintaining time is short as about 3 minutes.

5 is an image observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Comparative Example 4.

Referring to FIG. 5(b), it was confirmed that the agglomeration phenomenon was not seen, and the measured pot life was maintained well at 50 hours. That is, it can be confirmed that the pot life is increased by adding a stabilizer similar to Comparative Example 2.

However, referring to Fig. 5 (a), the sedimentation phenomenon is very large, and it can be confirmed that the bleeding rate is high as 15%, and referring to Fig. The holding time was about 4 minutes, confirming that the plastic state holding time was short.

6 is an image observing the state according to the bleeding rate, pot life, and plastic state maintenance time of Comparative Example 5.

Referring to Fig. 6 (a), it can be confirmed that the sedimentation phenomenon hardly appears, and it can be confirmed that the bleeding rate is as low as 6%.

In addition, referring to FIG. 6( c ), after about 7 minutes, the phenomenon of breakage and crumbling appears, and it can be confirmed that the plasticization state maintenance time is good. That is, it can be confirmed that the bleeding rate can be lowered by using bentonite with a high degree of swelling, and the plastic state maintenance time can be increased.

However, referring to FIG. 6(b), it can be seen that the liquid A is very hard, and the pot life is very short as 10 hours. In other words, if no stabilizer is added, it can be confirmed that the pot life of solution A is short.

That is, through Example 1, Comparative Example 2 and Comparative Example 4, it was confirmed that the pot life of the solution A could be increased by adding the stabilizer according to the present invention.

In addition, by adding bentonite of a certain degree of swelling or more together with the stabilizer, the effect of increasing the plasticized state retention time was confirmed, and when bentonite of a certain degree of swelling or more was used through Example 1, Comparative Example 2 and Comparative Example 4, the amount of bentonite It can be confirmed that there is an effect of reducing the .

In this specification, only a few examples among the various embodiments performed by the present inventors will be described, but the technical spirit of the present invention is not limited or limited thereto, and it is of course that it may be modified and variously implemented by those skilled in the art.

Claims (12)

Liquid A containing bentonite, plasticized slag cement, stabilizer and water; and
Liquid B containing sodium silicate;
A composition for backfill injection. According to claim 1,
The composition is
The liquid A is 80wt% to 95wt%,
The B solution is included in 5 wt% to 20 wt%,
A composition for backfill injection. According to claim 1,
The liquid A is
Based on the total weight of the liquid A, the cement is 20 wt% to 35 wt%,
The stabilizer is 0.1wt% to 0.5wt%,
The water comprises 62wt% to 78wt%,
Wherein the bentonite is included in an amount of 3 wt% to 15 wt% compared to the cement,
A composition for backfill injection. 4. The method of claim 3,
The plasticized slag cement includes Portland cement, slag powder and slaked lime,
Based on the total weight of the plasticized slag cement, the Portland cement is 45wt% to 75wt%,
The slag powder is 20wt% to 40wt%,
The slaked lime is included in 5wt% to 15wt%,
A composition for plastic backfill injection. According to claim 1,
The stabilizer comprises sucrose, citrate and water,
Based on the total weight of the stabilizer, the sucrose is included in an amount of 5 wt% to 30 wt%,
Composition for backfill injection 6. The method of claim 5,
The citrate is included in an amount of 50 to 150 parts by weight based on 100 parts by weight of the sucrose,
A composition for backfill injection. According to claim 1,
The degree of swelling of the bentonite will be 15 to 40,
A composition for backfill injection. According to claim 1,
The bleeding rate (material separation rate) of the solution A is 5% or less,
A composition for backfill injection. According to claim 1,
The pot life of the solution A will be 72 hours or more,
A composition for backfill injection. A method for preparing the composition for backfill injection of claim 1,
Preparing a liquid A comprising bentonite, plasticized slag cement, a stabilizer and water; and
Mixing the liquid B containing sodium silicate before proceeding with the backfilling by pumping the liquid A;
A method for preparing a composition for backfill injection. 11. The method of claim 10,
The step of preparing the solution A,
adding bentonite to water;
adding a stabilizer; and
Putting the plasticized slag cement;
A method for preparing a composition for backfill injection. 12. The method of claim 11,
In the step of adding bentonite to the water,
Add bentonite while stirring water,
When the input is completed, it is aged for at least 5 minutes,
A method for preparing a composition for backfill injection.

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