HU201108B - Process for increasing solidity and impermeability of soils and engineering establishments - Google Patents

Abstract

The invention relates to a method for improving the strength and impermeability of floors and technical structures, in particular Schaechten and pipelines. The aim is to reduce the technical-economic effort, to avoid health and environmental damage and to increase the life of the gel. The object is to provide a method by forming a hydrogel of silica and a crosslinked, swellable, organic polymer in or on the treated soil or structure, which ensures a simple and good processability of the mixture without adverse effects on the properties of the gel. According to the invention, an aqueous solution of a water-soluble, gel-forming vinyl monomer with a silica gel precursor in the presence of a redox polymerization catalyst system, a crosslinking agent for the resulting polymer, an organic polycarboxylic acid, optionally an additive which modifies the structure of the gel formed, and optionally contacted with a stuffing.

Description

The present invention relates to a method for increasing the strength and water tightness of soils and engineering installations, in particular ducts and pipelines. In the description and claim series, the terms "soil" and "engineering" are used in the broadest sense; these designations include the various reservoirs, pools, tunnels, natural and artificial caverns, rocks and the like, as well as the surrounding soil.

It is well-known that the watertightness of engineering facilities (such as underground channels, pipelines and reservoirs) is often inadequate, in part due to poor quality of construction materials, pipe joints, and damage to engineering facilities due to aging, traffic, and the like. It is also well known that the repair of engineering facilities (especially underground canals and pipelines) is extremely costly and laborious and in most cases the result is inadequate.

No. 153,975. The Hungarian patent describes a simple and fast method for increasing the strength and watertightness of soils and engineering facilities. According to the method described therein, the object to be treated is supplied with water or a medium containing water, and the water glass is then exposed to hydrogen fluoride, silicon tetrafluoride and / or hydrogen silicon fluoride. Water glass in contact with gaseous fluoride gels rapidly and completely breaks leaks, cracks and cavities. If this process is used for waterproofing underground engineering facilities (such as canals or reservoirs), there is an additional benefit of solidifying the water glass that enters the soil through cracks, thereby improving the bedding of the engineering facility and solidifying the surrounding soil. Another advantageous effect of fluoride gases is that they increase the corrosion resistance of concrete and reinforced concrete elements.

However, in spite of its many advantages, this method is practically applied only to a very limited extent. The widespread introduction of the process is severely hampered by the fact that hydrogen fluoride and silicon tetrafluoride are strong poisons and are therefore banned in most countries for environmental reasons.

To overcome this disadvantage, a number of processes have been developed which use gels which are not or only slightly harmful to the environment to gel the aqueous water glass solution (i.e., a highly alkaline aqueous solution of alkali metal silicate). Such a solution is described in the .Foundation Manual '(ed. L. Rózsa, Technical Publisher, Budapest, 1977) 756-783. wherein water soluble inorganic salts of silicic acid in solid form and inorganic or organic acids or esters capable of reacting with the aqueous solution of a water glass solution are used as gelling agents. No. 2,328,804. According to French patent no. 5, esters, aldehydes, mineral or organic acids or salts of mineral or organic acids are used to gel the aqueous solution of water. No. 2,242,713. German Patent Specification No. 4,752,002; U.S. Pat. No. 387,085. According to Soviet patent application, acrylic acid is added to the aqueous water glass solution as a gelling agent. The common chemical basis for these solutions is that the silicic acid is precipitated either by ionic action (using metal salts) or by consuming alkali for solution maintenance (acid-base reaction, ester saponification, Cannizzaro reaction, etc.).

A disadvantage is that the silica gel formed by the methods listed above is not elastic and thus unable to follow the movement of the treated object or the soil. Due to the inadequate swelling capacity of the silica gels, these gels are unable to block new cracks in the gel due to displacement. When organic compounds (such as organic acids, esters, or aldehydes) are used for gelation, the low molecular weight organic matter remaining in the gel structure slightly increases the deformability of the gel, but in this case the gel is too rigid and brittle; and in areas subject to shocks (such as highway traffic) - relatively short.

In another major group of known solutions, soil and art stabilizing gels are formed exclusively from organic materials. Such solutions are described in the quoted passage of the .Basic Handbook, whereby gels are formed from aminoplast, acrylic, or phenoplast resins. Nos. 177,343, 181,056, 181,775, and 181,573. Hungarian, Nos. 4,312,605 and 4,295,762. United States of America and U.S. Patent No. 1,074,246. In the British patent, hydrogels are formed in the soil by polymerization of various organic monomers, in particular acrylic and acrylamide monomers, followed by crosslinking. Polymerization catalysts are usually redox catalyst systems and crosslinking agents are aldehydes or water-soluble di- or trivinyl compounds (e.g. methylene bis-acrylamide). By these methods, gels that are sufficiently elastic and well-swellable are formed, but the gels are relatively soft and cannot withstand the detrimental effects of higher stresses. A further disadvantage is that the vast majority of monomers used as gelling agents are very expensive and

EN 201108 Β technology sometimes requires special equipment (such as injectors) and specially trained personnel.

The disadvantages listed are set forth in U.S. Patent No. 186,586. According to the method described in the Hungarian patent, the glass is used in combination with various gelling, water-soluble organic polymers and polymers with crosslinking agents. In these cases, as the silica gel precipitates, the polymer crosslinks and gels of mineral and organic units are formed, which combine the advantages of gels of fully organic and fully inorganic materials. However, the process is difficult to perform under large-scale operating conditions. Due to their high average weight, the gelling polymers, even at low concentrations, increase the viscosity of the stock water glass solution so that the resulting mixture is very difficult to handle and the application of the mixture and the removal of excess causes many technical problems. In some cases, the required amount of polymer may not be added to the solution in the water glass, as this would result in an extremely viscous, honey-like mixture which cannot be delivered to the object to be treated by the injection equipment available. Suitably low viscosity gelling compositions usually contain relatively small amounts of polymer, so that the gels formed do not attain the desired elasticity and swelling capacity.

It has been found that the advantages of gels which are wholly inorganic and of wholly organic substances can be combined, but at the same time the technical difficulties described above can be completely eliminated by starting from the monomers which form the gelling polymer instead of the preformed polymers and polymer crosslinking is performed in parallel with the silica gel formation.

The present invention relates to a process for increasing the strength and water tightness of soils and engineering plants by reacting a silica gel with a reaction of an alkali metal silicate with an organic acid in the soil, soil, facility or facility to be treated. forming a hydrogel. According to the invention, the silica gel and the organic polymer hydrogel are formed in parallel, optionally in the presence of a substance modifying the properties of the gel matrix, so that the area to be treated is simultaneously or sequentially in any order.

a) an alkali metal silicate in an amount of from 8 to 35% by weight and an oxidizing component consisting of an alkali metal persulfate or hydrogen peroxide and a lower oxidation metal salt, a reducing inorganic or organic acid and / or tertiary alkanol aniline; an aqueous solution containing from 0.2 to 2% by weight of an oxidizing or reducing component of a redox catalyst system (LA 'solution), and

b) a vinyl monomer selected from the group consisting of C3-C6 unsaturated mono- or dicarboxylic acid or its water-soluble salt and / or C3-C6 unsaturated mono- or dicarboxylic acid amide in an amount of 5-40% by weight with organic polycarboxylic acid; substituted, saturated or unsaturated C3-C10 aliphatic di- or tricarboxylic acids in an amount of from 3 to 25% by weight, a water-soluble di- or trivinyl compound in the amount of 0.2 to 2.5% by weight, and a redox catalyst system according to a) an aqueous solution (Solution B) containing 0.05-5% by weight of the vinyl monomer compatible component not included in Solution A 'is applied and the applied solutions are gelled.

If desired, urea, thiourea, methylurea and / or melamine may be added to the solutions A and / or B in amounts up to 15% by weight. All percentages reported refer to the total weight of solutions A and B, respectively.

It is extremely surprising to discover that upon contact (e.g. mixing) of solutions of the A and B formulations mentioned above, on the one hand, the polymerization of the silica gel and the polymerization of the monomer formed are simultaneously homogeneous over time, that is, gels containing organic and mineral constituents are formed. It is known from the previously cited publications that both organic polycarboxylic acids and unsaturated mono- or dicarboxylic acids used as monomers are commonly used precipitants in water glass. Thus, it was to be expected that when these materials were mixed, the silica gel would first be precipitated at high speed, and only then would the polymerization of the monomer take place over a substantially longer period, and the polymer formed would cure. As a result, a gel was expected to form on which a hydrogel formed from a purely organic material (a crosslinked polymer) was deposited on a core of a purely inorganic material (silica). Such dual-layer gels would essentially combine the disadvantages of gels consisting of purely inorganic and purely organic materials; because the flexible but inadequate polymer gel gel layer breaks easily and the strong but inelastic silica gel breaks easily and breaks down

HU 201108 Β. When using a salt with a lower oxidation state of a valence metal as a reducing component of the redox catalyst system (which is a typical precipitant in silica gel), it is also to be expected that the salt will separate with the silica gel and, in the absence of one catalyst component is happening. However, our practical experience contradicts these expectations. By using the aqueous solutions of the composition of the invention, the formation of the silica gel is significantly slowed down and the time of formation of the silica gel is practically equal to the time of polymerization and subsequent curing. The exact explanation of this phenomenon is unknown; it is hypothesized that silica gel precipitation is delayed by unidentified interface reactions.

Because the chemical sub-processes of the present invention proceed in parallel, and all intermediates formed during the chemical sub-processes interact with each other, a gel is formed in which the organic and mineral moieties merge. The gel formed can be clearly distinguished by simple visualization as described in U.S. Patent No. 186,586. gels prepared according to Hungarian Patent Specification. The latter gels are opaque and their structure is easily recognizable by the naked eye with organic and mineral constituents, i.e. a gel with an inhomogeneous microstructure. In contrast, the gels of the present invention are transparent, indicating a homogeneous microstructure. Thus, it is believed that the process of the present invention results in the formation of an organic / mineral copolymer instead of a mixture of separate organic and mineral polymer blocks.

In the process of the present invention, the alkali metal silicates are preferably used in the form of a concentrated aqueous solution of sodium or potassium water, which is diluted with water to the desired concentration.

The oxidizing component of the redox catalyst system used in the process of the invention may be an alkali metal persulfate or hydrogen peroxide, and the reducing component may be, for example, cobalt (II) chloride, sulfuric acid, ascorbic acid or triethanolamine. For compatibility reasons, the two components of the redox catalyst system should not be in the same solution and the aqueous solution of the vinyl monomer should not contain the oxidizing component of the redox catalyst system in free form (however, the solution may already contain the oxidizing component in masked form, e.g. .

Examples of vinyl monomers useful in the process of the invention include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, water-soluble salts of the listed acids, acrylamide and methacrylamide. These monomers may be used singly or in a mixture of two or more monomers.

Crosslinking agents which are commonly used for crosslinking vinyl polymers, such as methylene bisacrylamide, ethylene bisacrylamide and triacryl triazine, are commonly used as crosslinking agents. The curing agent must be sufficiently water-soluble; the solubility limit should not be less than 1% by weight.

Organic polycarboxylic acids used in the process of the invention include, for example, tartaric acid, succinic acid, citric acid, malic acid or ascorbic acid, optionally in the form of mixtures thereof. Ascorbic acid can also act as a reducing component.

If desired, any of the solutions A and B may contain one or more additives which modify the properties of the gel matrix formed, namely urea, thiourea, methylol urea and / or melamine. These substances have a softening, stabilizing or anti-decomposition effect.

If desired, one or more of the fillers commonly used in such compositions, such as asbestos, sand, fly ash, bentonite and the like, may be mixed with any of the solutions A and B. The amount of fillers is not critical; their amount is essentially limited only by technological factors (e.g., mixability and viscosity of the mixture, applicability of the mixture, etc.).

The consolidation of soils and engineering facilities in accordance with the present invention is accomplished by applying solutions A and B as defined above to the treatment site (such as soil or soil) and allowing it to gel. When the method of the present invention is used to solidify the soil, it is preferable to fill the two aqueous solutions into two containers of a two-tank injector with a stirring head and inject a mixture of the two solutions into the soil to be treated. Solutions A and B are preferably mixed in a weight ratio of (0.7-1.3): 1. If the method according to the invention is used for channel repair, it is preferable to use the so-called filling method, i.e. solutions A and B 'are successively filled into the channel to be treated; if necessary, the excess of the first solution is drained before filling the second solution. When repairing a heavily damaged, cracked canal, a significant part of the first solution will leak into the soil surrounding the canal. In view of this, for economic reasons, the solution containing the substantially less expensive materials is preferably firstly discharged into the channel to be treated. Due to leaks, the volume ratios of solutions A and B to be used may vary within wide limits,

HU 201108 Β and general ratios cannot be disclosed. However, the correct treatment rates can be readily determined by one of ordinary skill in the art.

The process of the present invention retains all the advantages of the processes described in the previously cited publications and patents. The process of the present invention, as well as known methods, provides a fast, safe and economical solution for solidifying and waterproofing soils and engineering facilities. Compared to known methods, the process according to the invention has the following additional advantages:

- does not require chemicals that are harmful to health or the environment;

- Provides a solid gel with elasticity and swelling ability to compensate for damage after repair (eg due to soil movement, traffic stress, etc.);

- the gel-forming mixtures are easy to handle and do not require any special equipment or special technological precautions;

- the process is significantly cheaper than the known, fully organic gel methods;

- the gel formed has a significantly longer lifetime than the gels formed by known methods, due to the homogeneous structure of the organic / mineral copolymer of the gel.

The process of the invention is described in the invention

without limiting it. in the examples below Example 1 The following composition of aqueous solutions we produce: The solution: potassium persulfate 1.4 massX Sodium silicate 20.6 wt thiourea 11.1 wt water gives 100.0 massX Solution B: methacrylic 16.2 wt tartaric acid 9.2 massX methylene-bis-acrylamide 0.46 wt iron (II) sulfate 0.46 wt water gives 100.0 massX

The solutions .A 'and .B' are mixed with vigorous stirring at a ratio of 1.16: 1 by weight. Within 7.5 minutes, a homogeneous, transparent gel was formed.

Example 2

The following composition aqueous solutions we produce: Solution A: potassium persulfate 1.4 massX Sodium silicate 20.6 wt thiourea 11.1 wt water ad 100.0 wt Solution B ': acrylic acid 14.7 massX succinic 9.2 massX methylene-bis-acrylamide 1.8 massX iron (II) sulfate 0.9 massX water ad 100.0 wt

Solutions A and B 'are mixed with vigorous stirring at a ratio of 1.15: 1 by weight. Within 1 minute, a homogeneous, transparent gel was formed.

Example 3

The following composition aqueous solutions we produce: potassium persulfate 0.8 wt melamine 6.2 wt Sodium silicate 11.5 wt water ad 100.0 wt Solution B: methacrylic 16.2 wt tartaric acid 9.2 massX methylene-bis-acrylamide 0.46 wt iron (U) sulfate 0.46 wt water ad 100.0 wt

Solutions A and B are mixed with vigorous stirring in a 1: 1 weight ratio. After 120 minutes, a homogeneous, transparent gel is formed.

Example 4

The following composition aqueous solutions we produce: Solution A: potassium persulfate 1.6 weight percent melamine 11.8 weight percent Sodium silicate 20.4 weight percent water give 100.0 wt Solution B ': itaconic 7.0 weight percent iron (II) sulfate 0.9 weight percent methylene-bis-acrylic -amide 0.9 weight percent citric acid 3.5 weight percent water give 100.0 weight percent

Solutions A and B are mixed with vigorous stirring in a ratio of 0.9: 1 by weight. Within 15 minutes, a homogeneous, transparent gel was formed.

HU 201108 Β

Example 5

Example 8

The following composition aqueous solutions The following composition aqueous solutions we produce: we produce: Solution A: 5. The solution: Sodium silicate 31.4 wt potassium persulfate 0.22 wt triethanolamine 0.8 wt monomethylolphenols urea 7.5 pounds x viz ad 100.0 wt Sodium silicate 23.2 massX Solution B *: water ad 100.0 txX acrylic acid 14.2 wt Solution 10-B ': citric acid 8.6 massX itaconic 10.0 wt H2O2-urea complex 3.45 massX acrylic acid 10.0 wt methylene-bis-acrylamide 0.43 massX citric acid 10 /) tómegX viz ad 100.0 wt triacrylate triazine 0.5 txX Solutions A and B vigorous stirring 15 ascorbic acid 0.2 massX with a weight ratio of 1.14: 1 mix one- ethylene-bis-acrylamide 1.0 wt else. Homogeneous, transparent gel within 18 minutes water ad 100.0 wt formed. Solutions A, and B vigorous stirring at a weight ratio of 1.3: 1 mix one- With 20 others. The mixture is 30 minutes homogeneous, Example 6 a clear gel is formed. The following composition aqueous solutions we produce: Example 9 The solution: 25 potassium persulfate 0.47 wt The following composition of the aqueous solution urea 9.53 massX we produce: potassium silicate 21.0 wt Solution A: viz ad 100.0 wt potassium persulfate 0.8 wt Solution B ': 30 sodium silicate 28.2 massX Sodium acrylate 8.5 wt water ad 100.0 wt methacrylic 9.4 wt Solution B ': ascorbic acid 12.8 wt itaconic 10.0 wt methylene-bis-acrylamide 0.85 wt maleic 20.0 wt viz ad 100.0 wt 35 tartaric acid 20.0 wt The solutions .A and .B ' vigorous stirring methylene-bis-acrylamide 1.0 wt while 0.9: 1 by weight mix one- cobalt! II-chloride 0.3 wt else. The mixture is 30 minutes homogeneous, viz · ad 100.0 wt a clear gel is formed. Solutions A and B ' vigorous stirring 40 at a weight ratio of 1.3: 1 mix one- else. The mixture is 15 minutes homogeneous, Example 7 a clear gel is formed. The following composition aqueous solutions Comparative experiment (A) we produce: 45 The solution: The following composition aqueous solutions potassium persulfate 1.5 massX we produce: urea 7.3 ttox The solution: Sodium silicate 22.9 massX potassium persulfate 1.7 wt water ad 100.0 wt 50 thiourea 13.2 wt Solution B: viz ad 100.0 wt acrylic acid 10.3 wt Solution B: methacrylic 4.7 wt acrylic acid 16.2 wt tartaric acid 9.3 massX tartaric acid 9.2 massX ethylene-bis-acrylamide 0.9 massX 55 methylene bisacrylamide 0.46 wt sulphurous 0.09 massX iron (II) sulfate 0.46 wt water ad 100.0 txX viz ad 100.0 wt

Solutions A, B and B are mixed with vigorous stirring at a ratio of 1.3: 1 by weight. The mixture forms a homogeneous 60 gels within 20 minutes.

Neither solution contains alkali metal silicate. Solutions A and B 'are mixed with vigorous stirring in a 1: 1 weight ratio. Within 12 minutes, a homogeneous, transparent gel consisting entirely of organic material was formed.

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HU 201108 Β (B) Comparative experiment

The following aqueous solutions we produce: The solution: thiourea 11.3% by weight Sodium silicate 20.9 hours% water gives 100.0% by weight Solution B ': methacrylic 16.2% by weight tartaric 9.2% by weight

methylene bisacrylamide gives 0.48% by weight of water to 100.0% by weight

In the absence of a redox catalyst system, no vinyl polymer is formed. The solutions .A 'and .B are mixed with vigorous stirring at a ratio of 1.15: 1 by weight. Within 1 minute, an opaque inorganic gel is formed which strongly synergizes.

In each of the examples listed, the amount of alkali metal silicate in dry matter was stated; the alkali metal silicate was used in each case in the form of a concentrated aqueous solution of sodium or potassium water (37% and 40%, respectively).

Compressive strength and deformation of gels prepared according to the examples and comparative experiments listed above were measured by known methods. The results are reported in Table I below.

Table I

The number of the example Compressive strength kg / m ² Deformation% First 21 48 Second 23 55 Third 15 60 4th 19 64 5th 17 51 6th 20 50 7th 22 48 8th 22 50 9 Comparative (A) 30 45 experiment 13 67 Comparative (B) experiment 2 5

From the data in Table I it can be concluded that the gels according to the invention are of higher quality than those obtained by known methods.

Example 10

Solutions A, A, and B of Example 1 are used to repair a channel as follows:

The channel section to be repaired is illustrated in Figure 1. The channel section delimited by shafts 2 and 3 is properly cleaned and then closed with shims 1 at the shafts. The sealed channel section is then filled with solution A 'through the shaft 2. The solution .A 'is stored in 4 containers. The pressure required to introduce the solution into the leakage passages, cracks, and cavities is achieved by filling the shaft with solution AA to a sufficient height. Depending on the channel defects through which the .A solution leaks, a solution level height of about 1-2 m is maintained in the well 2. If necessary, refill the solution in the shaft. After a suitable period of time (usually about 10-20 minutes), the remainder of the fluid is pumped back from the channel section through the shaft 2 to the container 4.

Then, as shown in Figure 2, solution B 'is discharged from the container 6 through the shaft 2. In this case, too, the pressure required to introduce the solution into the leakage passages, cracks, and cavities is provided by filling the shaft to the appropriate height with solution B '. If necessary, refill the solution. After a suitable period of time (preferably at the end of the leakage), the remainder of the liquid from the channel section is pumped back into the container 6 through the shaft 2 and the sealing elements 2 are removed. The repair is now complete.

If the effectiveness of the repair is to be verified by a water or air tightness test, the test may be performed before the closures are removed. However, this quality control operation may be omitted if solution a, B 'is kept in the shaft 2 for a sufficient time. When the level of the solution in the shaft 2 does not fall within 15 minutes or the level change is within the predetermined acceptable limit, this indicates that the channel is adequately watertight.

Solution A and B leaking from channel defects, imperfect joints, or cracks will form a stable gel inside and / or around the treated channel, thereby not only completely sealing the channel passageways, but also solidifying and sealing the soil surrounding the channel. Accordingly, the channel embedding conditions are greatly improved, a crucial factor for the stability and lifetime of the channel networks.

Claims (4)

PATENT CLAIMS 1. A process for increasing the strength and impermeability of soils and engineering plants, comprising reacting a silica gel with a reaction of an alkali metal silicate and an organic acid in a soil, soil, facility or facility to be treated, and characterized in that the silica gel and the organic polymer hydrogel are formed in parallel, optionally in the presence of a substance modifying the properties of the gel matrix, so as to be applied simultaneously or sequentially to the area to be treated, in any order. a) an alkali metal silicate in an amount of from 8% to 35% by weight and a redox consisting of an alkali metal persulphate or a salt containing a lower oxidation ion of a valence metal as a reducing component, a reducing inorganic or organic acid and / or a tertiary alkanolamine; an aqueous solution (solution A) containing 0.2 to 2% by weight of the oxidizing or reducing component of the catalyst system, and b) a vinyl monomer selected from the group consisting of C3-C6 unsaturated mono- or dicarboxylic acid or its water-soluble salt and / or C3-C6 unsaturated mono- or dicarboxylic acid amide in an amount of 5-40% by weight with organic polycarboxylic acid; substituted, saturated or unsaturated C3-C10 aliphatic di- or tricarboxylic acids in an amount of from 3 to 25% by weight; An aqueous solution (Solution B ') containing 0.05-5% by weight of the vinyl monomer-compatible component not included in the solution is applied and the applied solutions are gelled. 2. A process according to claim 1 wherein the gel matrix modifier is selected from the group consisting of urea, thiourea, methylol urea, and / or melamine. 3. A process according to claim 2 wherein the gel matrix modifier is added to the solutions A and / or B 'up to 15% by weight. Process according to any one of the preceding claims, characterized in that the solutions .A and .B 'are used in a ratio (0.7-1.3): 1 by weight.