NL8520094A - METHOD FOR IMPROVING THE STRENGTH AND IMPERMISSIBILITY OF SOIL AND TECHNICAL CONSTRUCTION WORKS - Google Patents

Description

- 1 - 8520094 NL 33641 WO-Kp / cs

Method for improving the firmness and impermeability j | soil suitability and engineering structures. j

The invention relates to a method for | the improvement of the firmness and impermeability of bo- J-! dem and engineering structures, in particular shafts and S pipelines.

δ! It is known that most engineering structures, such as subterranean shafts, pipelines and storage tanks, do not have the required impermeability properties, partly due to the inadequate quality of the construction; materials and in part :. due to impermeability damage 10! of the pipe joints or as a result of damage to the construction; work through aging, wear, etc. It is further known that the ambient temperature of engineering structures, particularly of underground shafts and pipelines, causes extremely high investment and labor, and in most cases the result is not satisfactory.

Hungarian Patent 153,957 provides a simple and rapid method for improving the solids; the impermeability and impermeability of soil and technical structures. According to this method, water glass or a 20i water-glass-containing medium is applied in or on the object i to be treated. The water glass is then turned on at the action j; ; of hydrogen fluoride, silicon tetrafluoride and / or fluorosilicic! '! I! exposed to acid. When water glass comes into contact with gaseous fluoride it stiffens quickly and completely closes holes and cracks and openings. By applying this method to waterproof underground structures (such as shafts or storage tanks), there is an additional advantage that 'i' water glass, which ends up in the ground through the cracks, also becomes solid there and therefore embedding the structure 30; improves and results in an increase in turnover | giving soil. Fluoride gases also have the advantage that they have the corrosion resistance of concrete and; improve concrete elements. !

Apart from these numerous advantages, this method has practically been used only to a very limited extent. A broad application! This method is largely determined by those facts 852 0 09 4 ......... '............. ~

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\ - 2 -! limits that hydrogen fluoride and silicon tetrafluoride in high! toxic, and their use is prohibited in most countries for environmental reasons. A further drawback is that the silica gel formed is not elastic the result is that it cannot follow the movements of the treated object or the bottom. Since the swellability of the silica gel is insufficient, it cannot close new cracks that form in the gel as a result of the movement.

In Hungarian Pat. Nos. 177,343, 181,056, 181,775, and 181,573, the use of various polymers. ! irisable organic monomers, primarily acrylic acids and acrylamide monomers as starting compounds for gel-forming reactions. The gels formed from such compounds are sufficiently elastic and have good water swellability. However, they are relatively soft and cannot withstand the damaging effect of higher loads. An additional drawback is that most of the monomers used as gelling agents are very expensive, while the gelling technology requires special training! and furnishing. j ί · |

The above drawbacks are addressed according to the following. avoid the current method, namely that in the Hungarian patent; applications 3124/82 and 967/83 have been proposed, namely that water glass when combined with various gel-forming water-soluble organic polymers and cross-linking agents | j; for the polymers: is used. In this case, a! silica gel formed at the same time as the crosslinking of the polymer to form gels consisting of | 30! mineral and organic blocks, which have the beneficial properties of the complete organic and complete mineral gels with: joining together ^. : It seems difficult to realize this method under large technical circumstances. Due to the high molecular mass, the viscosity of the starting water glass solutions is slightly increased by the gel-forming polymers, such that the resulting mixture is very difficult to handle. Its processing and the processing! disposal of excessive quantities creates numerous technical problems. Often the required quantity may be 85 2 O 094 .............. "......................... .......................

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- 3 - The polymer cannot be introduced into the waterglass solution because a very thick honey-like mixture is formed which cannot be adhered to the object to be treated. using standard spraying equipment. Gelling mixtures with the associated low viscosities j generally contain low polymer content, whereby the elasticity and the swellability of the resultant | gel is again unsatisfactory.

The object of the invention is to improve the technical economics

Reduce clinical costs, health and environmentally harmful '. avoid aspects and increase the life of the gel.

To this end, the invention provides a method for; the improvement of the firmness and impermeability of soil and technical structures by forming a hydro-! silicic acid gel and a cross-linked, swellable, organic polymer in or on the soil or treated structure, without detrimental effect on the properties of the gel, allowing a simple and good processability of the mixture.

To this end, the invention provides a method in which an aqueous solution of a silica gel precursor is mixed with a water-soluble, gel-forming vinyl monomer in the presence of a redox polymerization catalyst system, a cross-linking agent for the polymer obtained, an organic polycarboxylic acid, i - optionally an additive which enhances the properties of molded gel matrix modifies, and ί30 - optionally a filler.

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It has been found that the aforementioned difficulties and drawbacks of the known prior art can be avoided. when instead of the precursor formed! polymers, the monomers leading to the gel-forming polymers, are added to the water glass and the polymerization is carried out. ! and the cross-linking of the polymer takes place simultaneously with the formation of the silica gel.

; Accordingly, the invention relates to a method for improving the firmness and impermeability. 85 2 0T94 "....." "........ ..... "............" .......... ".................... ............. "

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Permeability of soil and technical structures through the formation of a hydrogel consisting of silicic acid and a cross-linkable, swellable organic polymer in or on the treated soil or structure.

; In this regard, it is noted that the terms "soil" | j and "technical structure" also include various storage tanks, tunnels, natural and man-made cavities, rocks (rocks), etc., as well as the surrounding soil.

10 When contacting the aqueous solution! ! ! of a precursor of silica gel (e.g. an aqueous solution of water glass) with a water-soluble gel-forming vinyl monomer in the presence of the components described above - the following chemical processes proceed: M5 - the monomers polymerize according to the action of the fedox catalyst system, - the linear polymers obtained react with the cross-linking means to form a cross-linked polymer gel, and A silica gel is formed from its precursor by the action of the polycarboxylic acid.

| Since these chemical processes run in parallel and | all formed intermediates in the process interact; interact, a gel is formed, whereby the organ! mineral and mineral parts are amalgamated. The visual

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The appearance of the gel obtained differs clearly. that of the gels obtained according to J

I Hungarian patent applications 3124/82 and 967/83. The last gels 1 1 y! are opaque and the organic and mineral blocks can be easily distinguished in their structure, that is to say, a gel is obtained with an inhomogeneous | microstructure. In contrast, the gels, which according to the invention! invention, transparent, indicating a homogeneous microstructure. On the basis of this, it can be assumed that an organo-mineral copolymer is formed, on the contrary. into a mixture of organic and mineral polymer block-1 ί 1.

! i; | j According to the present method, a suitable Ι | substance which forms in contact with an acid silica gel if .......... J silica gel precursor are used. The preferred representative 8520094

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- 5 -! The ingredients of the silica gel precursor are the various water glass types (sodium silicate, potassium silicate, etc.). However, water-soluble silicones and polysilicates can also be used, such as, for example, those used for molding.

Examples of water-soluble gel-forming vinyl monomers are: acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, water-soluble salts and esters of such acids, acrylamide, methacrylamide, and so on. These monomers can be used alone or as a mixture of two or three monomers.

As the cross-linking agent for the organic polymer, for example, aldehyde (such as glyoxal, glutaraldehyde, etc.) or diviryl or trivinyl compounds (such as methyl-15: lene-bis-acrylamide, ethylene-bis-acrylamide, triacryltri-1 'azine, etc.). are used. The cross-linking agents. : must be sufficiently water-soluble, the soluble! ] in water should be at least 1%.

The redox catalyst systems to be used according to the invention consist of an oxidizing and a reducing compound. Any suitable known free radical initiator system! Redox type cals commonly used in the preparation of i | j vinyl polymers are used, can be used. The oxide component can be, for example, hydrogen peroxide, an alkali metal sulfate or a water-soluble organic perazide, while the reducing component can be, for example, a water-soluble one. [organic amine, a water-soluble salt of a metal of varying dignity, a thiosulfate, a bisulfite, etc; [can be further.

1 1 30; The polycarboxylic acids to be used according to the invention (which are organic carboxylic acids with at least two carboxy groups) are, for example, tartaric acid, succinic acid. 1 | acid, citric acid, malic acid, ascorbic acid, etc.

The ratio of silica gel precursor to vinyl monomers, based on the dry matter, can vary within a wide range, for example from 10: 1 to 1:10, preferably j! 5: 1 to 1: 1. Preferably it is from 4: 1 to 2: 1. For economic reasons, it is preferable to use the vinyl monomer i in a small amount. It should be noted that 852 0094 ...... “'......................." ............ ...........

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I essentially the elasticity and swelling properties of the gel remain the same as for the fully organic gel: with a high mineral organic ratio, whereby additionally the higher the silica content of the gel, the firmness 5 | and load resistance is all the greater.

I The ratio of silica gel precursor to poly-

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i carboxylic acid, calculated for the dry matter, can lie 1: 0.3 to! 1: 0.6, preferably 1: 0.2 to 1: 0.08, especially 1: 0.1-1 The amount of cross-linking agent calculated for the; ! The amount of vinyl monomer present can be 1: 0.01 to. i are 1: 0.3, preferably 1: 0.05 to 1: 0.2.

J The amount of the redox catalyst system, be! ! calculated for the mass of the vinyl monomer present, | 1: 0.01 to 1: 0.5, preferably 1: 0.05 to 1: 0.3.

I15! Within this range, the catalyst system can convert the oxidizing agent Contain the reducing components, preferably in about equimolar amounts.

If desired, the formed mixture may also contain one or more additives, which modify the properties of the formed gel. These additives can be the usual known additives for the cross-linked vinyl polymers, for example plasticizers, stabilizers, anti-decomposition agents, etc., which may be mentioned melamine, urea, monomethylolurea and thiourea. The quantities of 25! such additives, if present, may be as large as those of the vinyl monomers.

; If desired, the gel-forming mixture may contain one or more filler (s), which are generally found in such ! mixtures are used, such as, for example, asbestos, sand, fly ash, bentonite, etc. The amount of such! ! fillers are not critical and are in principle used by techno! I logical factors were determined (for example, the stirability and viscosity of the mixture, handling of the mixture during application, etc.).

When using the method according to the invention for the treatment of soil or technical structures, it is possible to proceed in such a way that the individual components of the gel-forming mixture are arranged in a suitable order, i of the compatibility, directly at the place of i 852 0 09 4 609409LC ^ - 7 - j, can be mixed together (for example i i I with defective pipe to be repaired). In any case, it is preferable to start with two prepared aqueous solutions! and compare them at the treatment site 5 | to blend. The compositions of the two aqueous solutions should be chosen so that both solutions in progress | of a longer period of time remain stable and storable, in which case in any case no premature gel formation takes place.

! When choosing the suitable composition of the solutions, the following factors must be taken into account: - the silica gel precursor must not exist in a conventional solution with the polycarboxylic acid; | - the two components of the redox catalyst system must not exist in a usual solution; and 15j - the aqueous solution of the vinyl monomer must not enter the oxidizing components of the redox catalyst system; free state (although the oxidizing components can be in masked form, such as complex).

! ;

Taking into account the above factors, the two aqueous solutions, which can be mixed together at the treatment site, can have the following compositions:

Solution "A": Silica gel precursor (for example, water |! Glass), 25! oxidizing components of the redox catalyst system; j

Solution "B": water-soluble vinyl monomer, cross-linking agent for the organic polymer! · "A polycarboxylic acid, I" [reducing components of the redox catalyst! torsion system,! j water; Solution I "B": water-soluble vinyl monomer, i a cross-linking agent for the organic polyphomer, a polycarboxylic acid, i oxidizing components of the redox catalyst 0520094

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- 8 -! Masked system (for example, in a complex with urea), water; j

Solution "A": a silica gel precursor, 5I reducing components of the redox catalyst system, I water.

The optional additives and fillers can be added to any of the solutions "A" and "B", insofar as compatibility allows. For example, an acidic J filler (e.g., acid fly ash) should not be added to the solution of the [silica gel precursor.

As explained above, the method according to the | invention in the construction industry for improving the j 15; firmness and impermeability of soil and technical structures are applied. For this purpose, the separate | components of the gel-forming mixture - preferably in two previously prepared aqueous solutions - together on the building site! I place mixed, for example in or on the ground or in or on 20: the technical structure. When, for example, the working method; according to the invention is used for strengthening. ; from the bottom, the two aqueous solutions are added! Preferably in a barrel of a two-barrel sprayer. i i ting, which is equipped with a mixing head, transferred, where! The mixture of the two solutions is injected into the base to be treated. When, according to the present method, a tube shaft is to be repaired, it is preferred to work according to the so-called "filling" technique, wherein the two solutions are introduced successively into the tube to be repaired.

The method according to the invention has all the advantages described in the aforementioned patents and patent applications. As with the known method, vol! ! fast, secure and economical according to the present method! 3 5! guaranteed to make the soil I j or technical structures strong and watertight. The method according to the invention has the following additional advantages compared to the known methods: - no chemicals are required which are harmful to health or the environment; i 8520094 609-109LC w - 9 - I; J- it results in a strong gei, which is sufficiently elastic! and is swellable, to repair damage caused after repairs j, for example due to ground movements, shifts due to traffic, and so on; - the gel-forming mixtures are easy to handle, the I treatment requires no special equipment and no play! vital precautions; In addition, the method is hardly more expensive than the known ones, using only organic gels; The service life of the gel prepared exceeds that of the gel prepared according to the known method, which can be traced back to the homogeneous organo-mineral copolymer structure of the gel. The invention will now be explained with reference to a few;

examples explained in more detail. In the drawings, fig

i: | :in front of:

Fig. 1; the schematic representation of a | solid pipe section, in which solution "A" is injected; 20 brought. . ! «. j

Fig. 2: the pipe section according to FIG. 1, into which the solution "B" is introduced.

I j | j 'EXAMPLE 1!

Ij Two aqueous solutions of the following composition were prepared:

Solution "A" water 40 ml potassium persulfate 1.8 g thiourea 14 g 30: concentrated aqueous water glass (solution: solution) with a dry matter content

of 37 mass / mass% 50 ml I.

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Solution "B" water 80 ml] methacrylic acid 16 ml j tartaric acid 10 g 35: methylene bis-acrylamide 0.5 g -.......- | iron sulphate 0.5 g 85 2 0 0 9 4 ..... "................................. ................ "..........."

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These two solutions were mixed together under intensive stirring. A homogeneous transparent tile was obtained within 7.5 min.

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| Comparative test A

5; Two aqueous solutions were added with the following! composition prepared: j i Solution "A"! i water 90 ml i potassium persulfate 1/5 g i 10! thiourea 14 g | Solution "B"! water 80 ml acrylic acid 16 ml tartaric acid 10 g 15 methylethylene bis-acrylamide 0.5 g ferrous sulfate 0.5 g i

Water glass did not appear in any of the solutions. The two solutions were mixed together under intensive stirring. A homogeneous transparent, completely 201 organic gel was obtained in 12 minutes.

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i Comparative test B

J Two aqueous solutions of the following composition were prepared:

Solution "A" 25 water 40 ml thiourea 14 g concentrated aqueous water glass solution (dry matter content 37 mass / mass%) 50 ml

Solution "B" water 80 ml 30 acrylic acid 16 g j

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i tartaric acid 10 g j! methylene bis-acrylamide 0.5 g | i; ^ ^ ^ ^ • l - 11 -

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Since no redox catalyst system was present, no vinyl polymer could be formed. The two solutions j were mixed together under intensive stirring. Within j | A cloudy mineral gel was obtained for 1 min. The gel had a: 5; strong discomfort (Synaresis).

EXAMPLE II

Two aqueous solutions of the following composition were prepared:; ! 1! Solution "A"

J

10 water 40 ml potassium persulfate 1.8 g thiourea 14 g concentrated water glass solution (dry matter content 37 mass / mass) in aqueous form 50 ml

Solution "B" 15 iwater 80 ml [acrylic acid 16 g succinic acid 10 g methylene bis-acrylamide 2 g J iron sulfate 1 g i i i 20! The two solutions were mixed together under strong stirring. A homogeneous transparent J gel was formed within 1 min. j I i j! i EXAMPLE Owl j! Two aqueous solutions with the following 25 were added; composition prepared: Solution "A" | : water 70 ml potassium persulfate 0.9 g J melamine 7 g 30 concentrated aqueous water glass solution

; (dry matter content 37 mass / mass) 25 ml I.

i i 'Solution "B"! water 80 ml I:! | ! methacrylic acid 10 ml j 1 | 00J 4 -12-tartaric acid 10 g of methylene-bis-acrylamide 0.5 g; iron sulfate 0.5 g i! Both solutions were stirred with intensive stirring mixed together. A homogeneous transparent gel was obtained within 120 minutes. j | i

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i EXAMPLE IV

j Two aqueous solutions containing the following | composition prepared:

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10'Solution "A" 1 water 16 ml potassium persulfate 0.8 g | melamine 6 g i concentrated aqueous water glass solution j (dry matter content 37 mass / mass%) 15 Solution "B" water 50 ml i itaconic acid 4 g ferrous sulfate 0.5 g i methylene bis-acrylamide 0.5 g 20 citric acid 2 g

The two solutions were mixed together under intensive stirring. Within 15 min a homogeneous transparent gel. obtained.

EXAMPLE V

25; Two aqueous solutions containing the following | ! composition prepared: j

Solution "A" water 19 ml concentrated aqueous water glass solution (dry matter content 37 mass / mass%) 80 ml i30 triethanolamine 1 ml i!

Solution "B" ii water 85 ml j acrylic suction 15 ml 152 O öi'V ................................. ... '~~ ....................................... ~

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η - 13 - i! i citric acid 10 ml j! ;

j hydrogen peroxide in the complex with urea 4 g I.

! methylene bis-acrylamide 0.5 g I.

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! i I! The two solutions were mixed together under intensive stirring. A homogeneous transparent gel was obtained within 18 minutes.

The pressure resistance and deformation of the according to the; Gels prepared above and comparative examples were measured by standard methods. The re-J10j results are summarized in Table 1. The tables show j | | it is clear that the gels prepared according to the invention are super

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| relative to the method prepared according to the known method! i gelen.

! j! TABLE 1 15 Example No. Pressure resistance Deformation _ kg / cm2 __% _ I 21 48 II 23 55 III 15 60 'IV 19 64 20! V 17 61 i [Comparative test A 13 67 j 1 j [Comparative test B 2 5 | | --- i

; EXAMPLE VI

| The solutions "A" and "B" with the in Example I again | I! 25 | given compositions were used for the repair of a tube in the following manner: j

The pipe section to be treated is shown in Fig. 1.! ; The pipe section bounded by shafts 2 and 3 was positioned at j; Purified in the usual manner and subsequently blocked with 301 by means of the pipe valve 1. Then the closed tube section was filled up with the solution "A" via tube 2. The solution "A" was stored in tank 4. The requirement j | press to press the solution into the holes, fractures and cavities; by filling the shaft to suitable heights-35; brought too. Depending on the breaking points of the pipe, a solution height of approximately 1-2 m in the shaft 2 was maintained, depending on the breakage points of the pipe, 8520 09 4 60S409LC ww W $ - 14 - "lj through which solution" A "emerged. The solution in the shaft was replenished if necessary After a suitable period of time, generally after 10-20 min, the residual liquid from the tubing was pumped back into the tank 4 via shaft 2.

Then, as shown in FIG. 2, the solution | "B" from the tank 6 is introduced into the pipe section via the shaft 2. Watch for pressing the solution, i | 10; fractures and voids required pressure was again reduced by the backfill; ; the shaft until it reaches the appropriate height. The sol-i | If necessary, it was replenished. After an appropriate time | | expensive, preferably when nothing runs out, the rest of the liquid in the tank 6 was pumped back via the shaft 2, after which the tube valves were removed. With that! the repair had ended.

| i If the results are to be checked using watertightness tests using water or air, this may be done by removing the; 20j pipe valve to take place. This quality control can be avoided by leaving the solution "B" in the! shaft 2 for an appropriate period of time. If the level of the solution in the shaft 2 does not decrease within 15 minutes (or the decrease remains within the prescribed tolerance limits), this is a sign that the tube: 1 is watertight. !

The solutions "A" and "B" leaked into the and / or in the vicinity of the treated tube due to damage, unwanted joints or fractures of the tube form a stable gel 5. This is not only the case for the insurance plate - to completely block the pipes, but also to block the boom stiffen and waterproof the pipe surrounding the pipe. j

Accordingly, the embedding conditions of j; improve the tube to a high degree, making a decisive 35; factor in view of the stability and service life of the pipelines.

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Claims (4)

1. Method for improving the firmness and impermeability of soil and technical structures through the | forming a hydrogel from silica and a crosslinkable, swellable, organic polymer in or on the ground or treated structure, characterized in that an aqueous solution of silicic acid precursor is mixed with an aqueous polymeric precursor. water-soluble, gel-forming vinyl monomer in the presence of i - a redox polymerization catalyst system, i - a cross-linking agent for the polymer present, 10 '- an organic polycarboxylic acid, J - optionally an additive which modifies the structure of the j gel formed, and - optionally a filler. j '! 2. Process according to claim 1, characterized in that the components of the gel-forming mixture are mixed by i! mixing two previously prepared aqueous solutions j are mixed together. ! 3. Process according to claim 2, characterized in that one of the two aqueous solutions is the silica acid gel precursor, the oxidizing components of the redox catalyst. lysator system and optionally an additive and / or a filler ; and the other aqueous solution from the water solution | bare vinyl polymer, the cross-linking agent, the polycarboxylic acid; the reducing components of the redox catalyst system 25i and optionally an additive and / or a liquid exist. 4. Process according to claim 2, characterized in that one of the aqueous solutions from the silica | acid gel precursor, the reducing components of the redox catalyst system and optionally an additive and / or a filler! dust exists, while the other aqueous solution is the water; soluble vinyl polymer, the cross-linking agent, the polycarboxylic acid, the oxidizing components of the redox catalyst system in masked form and optionally an additive and / or. ! contains a filler. j i i IIJ o o s c '