A METHOD FOR PREPARING AN INJECTION MATERIAL AND THE OBTAINED INJECTION MATERIAL

Abstract

Disclosed is a method for preparing a mixture and the injection material to be used as soil injection material to close the pores after a certain gelling period by applying it to the pores in the silt size, including the steps of: (a) preparation of a mixture of sodium silicate with a SiO2/Na2O ratio of 3-4 and water so that their ratio by volume varies between 3/7 and 1/1; (b) obtaining a mixture by dissolving ultra-low sulfated boric acid in water, containing between 2.5-5% by weight of ultra-low sulfated boric acid; and (c) mixing the obtained ultra low sulfate boric acid-water mixture with sodium silicate in the step a.

Claims

1. A method for preparing a material to be applied as a permeation injection in soils up to silt size, the method comprising the steps of: a) Preparation of a mixture of sodium silicate with a Si02/Na20 ratio of 3-4 and water so that their ratio by volume varies between 3/7 and 1/1; b) Obtaining a mixture by dissolving ultra-low sulfated boric acid in water, containing between 2.5-5% by weight of ultra-low sulfated boric acid; and c) Mixing the obtained ultra low sulfate boric acid-water mixture with sodium silicate in the step a.

2. The method of claim 1, wherein the Si02/Na20 ratio of sodium silicate is 3.2.

3. The method of according to claim 1, wherein ultra low sulphate boric acid is dissolved in water with a magnetic stirrer.

4. The method of claim 1, further comprising increasing the rate of ultra-low sulfated boric acid added to water to reduce gelling time or to decrease gelling time.

5. A soil injection material that improves said soils after a certain gelling time by being applied as a permeation injection to soils up to silt size obtained by the method of claim 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0020] In this detailed description, a method for preparing an injection material according to the invention and the injection material obtained are described only with examples that will not have any limiting effect in order to better understand the subject.

[0021] The subject of the invention is related to the method for the preparation of materials for the geotechnical engineering, where cement mixtures are insufficient, and the construction of dam soils, tunnel constructions, permanent and temporary deep excavations, rock fissures, and permeation injections up to silt size.

[0022] In the method of the invention, it is explained how to control the gelling time with the use of ultra low sulfate boric acid. Here, the expression “ultra low sulphate boric acid” is limited to boric acids containing sulphate at a maximum rate of 3 ppm.

[0023] Sodium silicates, known as water glass, are prepared by heating silicate sand or silica of any form with Na.sub.2CO.sub.3 at around 900° C. After refining, sodium silicate becomes a fluid solution. This solution can be diluted with water to obtain the concentration that meets the need. Sodium silicate is neutralized and gelled using a weak acid or salt acid as a reactant.

[0024] In order for sodium silicates to be used as the injection material described in the invention, it is essential that the silica/alkali ratios (SiO.sub.2/Na.sub.2O) are between 3 and 4. In a preferred embodiment, this ratio is 3.2.

[0025] Organic or inorganic reactants are used in the gelling process of sodium silicates. In this invention, sodium silicate and ultra-low sulfated boric acid of inorganic origin are used. Ultra low sulphate boric acid is dissolved by mixing in water in the mixtures and then mixed with sodium silicate in certain proportions. Sodium silicate and ultra low sulfate materials are mixed and the following reaction occurs.

##STR00001##

[0026] According to the reaction equation, when sodium silicate, which is alkaline in nature, is diluted, it ionizes by hydrolysing in aqueous medium. Na.sup.+ cations and tetrahedral silica chains are surrounded by H.sub.2 molecules. When an aqueous ultra low sulfate boric acid solution with concentrated concentrate is added on this alkaline solution, it gradually enters the sodium silicate chains of the polymeric chain structure, which is in the form of a polymeric chain, and draws the pH of the environment towards neutral levels.

[0027] When the ambient pH is neutral, the polymeric sodium borosilicate structure proposed by the products in the above reaction begins to form and mechanical setting occurs accordingly.

[0028] When a trigonal structure ultra low sulfate boric acid aqueous solution is prepared, it turns into a tetragonal (a geometry similar to silicate structure) with hydrolysis, which facilitates the formation of a silicate-like chain to enter among polymeric silicate derivatives. The tetragonal borate structure in anionic character increases the stability of the hard material formed by balancing its charge with the cationic Na.sup.+ atoms in the sodium silicate structure.

[0029] The reaction that takes place between sodium silicate chains and tetragonal borate anions is a kind of esterification reaction, which is carried out through H.sub.2O elimination. As a result of the reaction described above, the solution gelates.

[0030] 48 different injections of 100 ml prepared with the inputs in the range given in Table 1 and their gelling times are shown. Here, ultra-low sulphate boric acid is mixed with sodium silicate by using a magnetic stirrer.

TABLE-US-00001 The amount of Sodium boric acid in Boric acid silicate 100 milliliter (by mass)/ Mixture content Water of solution water Gelling times code (ml.) (ml.) (gr.) (%) (dk.) B1 30 70 3.05 4.3 10 B2 30 70 2.82 4 13 B3 30 70 2.61 3.7 23 B4 30 70 2.41 3.4 37 B5 30 70 2.22 3.1 112 B6 30 70 2.05 2.9 187 B7 30 70 1.81 2.6 275 B8 32 68 3.02 4.4 12 B9 32 68 2.82 4.1 19 B10 32 68 2.63 3.8 33 B11 32 68 2.39 3.5 60 B12 32 68 2.22 3.2 140 B13 32 68 2.03 2.9 240 B14 32 68 1.84 2.7 305 B15 34 66 3.02 4.6 18 B16 34 66 2.81 4.2 20 B17 34 66 2.62 3.9 45 B18 34 66 2.43 3.6 75 B19 34 66 2.21 3.3 184 B20 34 66 2.03 3 374 B21 34 66 1.82 2.8 500 B22 36 64 3.01 4.7 20 B23 36 64 2.82 4.4 26 B24 36 64 2.61 4.1 59 B25 36 64 2.43 3.8 110 B26 36 64 2.22 3.4 252 B27 36 64 2.04 3.1 440 B28 36 64 1.82 2.8 570 B29 38 62 2.91 4.7 27 B30 38 62 2.82 4.5 35 B31 38 62 2.73 4.4 55 B32 38 62 2.62 4.2 65 B33 38 62 2.53 4 97 B34 38 62 2.42 3.9 134 B35 38 62 2.31 3.7 230 B36 40 60 2.84 4.7 39 B37 40 60 2.72 4.5 61 B38 40 60 2.61 4.3 81 B39 40 60 2.53 4.2 114 B40 40 60 2.42 4 151 B41 40 60 2.35 3.9 262 B42 40 60 2.22 3.7 380 B43 42 58 2.83 4.9 62 B44 42 58 2.74 4.7 109 B45 42 58 2.62 4.5 137 B46 42 58 2.51 4.3 158 B47 42 58 2.42 4.1 245 B48 50 50 2.22 4.4 22

[0031] As can be seen in Table 1 examples B1-B7, while the amounts of water and sodium silicate have been steadily provided, the gelling time of the injection increases regularly as the amount of ultra-low sulfated boric acid decreases.

[0032] In addition, as can be seen in B8, B23, and B31, the amount of ultra-low sulphate boric acid is kept constant by mass, and the gelling time increases when the volume of water is increased compared to sodium silica. In contrast, when the ratio of sodium silicate to volume increases, gelling time decreases.

[0033] Strength and Permeability Values Obtained by the Said Injection;

[0034] By injection, the unconfined compressive strength of sand samples can be up to 0.50 MPa and the unconfined compressive strength of silt samples can be up to 0.30 MPa. Also, with the developed injection, the permeability coefficients of sand samples decrease to 1×10.sup.−6 cm/sec and the permeability coefficients of silt samples to 1×10.sup.−7 cm/sec.

[0035] The scope of the protection of the invention is set forth in the annexed claims and certainly cannot be limited to exemplary explanations in this detailed description. It is evident that one skilled in the technique can make similar embodiments in the light of the explanations above without moving away from the main theme of the invention.