High-pressure grouting is to inject water-soluble polyurethane chemical grouting material into concrete cracks by using the high-pressure power of machinery (high-pressure grouting machine). When the slurry meets the moisture in concrete cracks, it will quickly disperse, emulsify, expand and consolidate, so that the consolidated elastomer can fill all concrete cracks and completely block the water flow outside the concrete structure, thus achieving the purpose of stopping water and plugging. High-pressure grouting plugging technology is a new waterproof technology of high-pressure airless grouting with international advanced level, and it is also a new technology used for water-soluble grouting materials in developed countries.
Second, the principle of high-pressure grouting plugging
Water-soluble polyurethane chemical grouting material is an oligomeric urethane prepolymer containing free isocyanate groups prepared in advance from excess polyisocyanate and polyhydroxy compounds.
Commonly used polyisocyanates are TDI, MDI and PAPI. The polyhydroxy compound adopts polyether, and its functional group and molecular weight can be several. After cement slurry is poured into concrete cracks, it will react with water leakage, releasing carbon dioxide and forming urea derivatives. So as to achieve the purpose of seepage prevention and plugging.
Water-soluble polyurethane chemical grouting material is a kind of one-component synthetic polymer polyurethane material with low viscosity, which is in slurry form. It has the characteristics of cross-linking reaction in water and foaming to form a multi-element network closed elastomer. When it is injected into the concrete crack structure by high pressure, until all cracks (including cracks imperceptible to the naked eye) are filled, it releases a large amount of carbon dioxide gas after meeting water (water injection), resulting in secondary seepage pressure. High-pressure thrust and secondary seepage pressure push the elastomer into and fill all cracks, thus achieving the purpose of plugging. It can be seen that water-soluble polyurethane chemical grouting material is one of the best plugging materials, and leakage cannot be cured by ordinary materials. After the high-pressure grouting plugging technology was adopted, the plugging was successful once.
Third, the mechanism of high-pressure grouting plugging
1, forming a chemical link to the fracture.
2. Form high-strength anchor bolts for the pores on the surface.
3. Fill all cracks under high pressure.
Fourth, the application characteristics of high-pressure grouting plugging technology
1, highly completed;
2, simple operation;
3, can be constructed in four seasons;
4, non-toxic and pollution-free;
5. The cost is reasonable.
Verb (abbreviation of verb) Application scope of high-pressure grouting plugging technology
1, plugging and sealing of cracks, expansion joints, construction joints and structural joints in various buildings and underground concrete projects.
2, geological drilling engineering borehole wall plugging reinforcement.
3. Reservoir dam grouting, water conveyance tunnel crack plugging, seepage prevention, dam concrete crack seepage prevention and reinforcement in water conservancy and hydropower projects.
4, high-rise buildings and railway, high-grade highway subgrade reinforcement and stability.
5, coal mining or other mining engineering roadway water plugging, roof and other broken layer reinforcement.
6. Bridge foundation reinforcement and bridge cracks.
7. Reinforcement of deformed buildings and cracks in concrete structures such as water towers and pools to prevent settlement.
8, soil improvement, soil surface protection and stability reinforcement, etc.
Six, high pressure grouting plugging construction method
1. Inspection: Carefully inspect the leaking part and clean up the dirt near the leaking part for grouting.
2. Hole arrangement: drill grouting holes in the leaking parts. For deep cracks, inclined holes can be drilled through the joint surface, and the general hole spacing is 20 cm-50 cm.
3. Buried nozzle sealing: Buried grouting nozzle, sealed with polymer cement.
4. Grouting: Grouting pressure and grouting quantity should be determined according to the specific situation of the leakage part. Use a plugging grouting pump to pour this product into the crack. When pure slurry appears in all adjacent holes, move it to the adjacent holes, grout it under the specified pressure until it cannot be pushed forward (injection rate ≤0.0 1L/min), and then close the valve. (Generally, the grouting pressure is 0.3Mpa).
After 5.72 hours, check whether there is water seepage in the leaking part. If there is no water seepage, break the grouting nozzle and seal the base surface with polymer cement.
Seven, the basic technical parameters of high pressure grouting plugging agent (see instructions)
Density (23℃) 1. 1g/cm3.
Viscosity (23℃):250-350 mPascals per second.
Reaction times with water: 10-20 times.
Suitable temperature: +5-55℃
Working pressure (i.e. pressure range of the plugging device): 0-70 MPa.
Reaction time: (mixed with 5% water)
Start reaction: 10- 15 seconds development period: 50-60 seconds formation period: 2-3 minutes.
Eight, high pressure perfusion machine
Nine, high pressure grouting crack construction technology
Structural cracks and water leakage
1. Obliquely drill to half of the structural depth at 5 ㎝ ~ 10 ㎝ on the left or right side of the lowest fracture, and drill from the lower part to the upper part in turn, with the hole spacing of 20 ㎝ ~ 30 ㎝. After drilling to the highest place, bury the grouting water stop needle, because the cracks in the general structure are irregular.
2. After the grouting water stop needle is set, it is poured with water-soluble polyurethane chemical grouting material until the grouting liquid seeps out on the surface of the structure.
3. After the grouting is completed, the grouting water stop needle can be removed.
Construction joint leakage
1. At the 5 ㎝ ~ 10 ㎝ on the left or right side of the lowest position of the construction joint, drill obliquely to half the thickness of the structure, drill from the lower position to the higher position in turn, with the hole spacing of 20 ㎝ ~ 30 ㎝, and bury the water stop needle again after drilling to the highest position.
2. After setting the grouting water stop needle, inject the water-soluble polyurethane chemical grouting material with a high-pressure grouting machine until the grouting liquid seeps out on the surface of the structure.
3. After the grouting is completed, the grouting water stop needle can be removed.
Honeycomb leakage
1. Drill a hole every 25 ㎝ ~ 30 ㎝, the depth should be half of the thickness of the structure, then bury the grouting water stop needle and tighten it.
2. After the grouting water stop needle is set, the water-soluble polyurethane chemical grouting material is injected into the high-pressure grouting machine until the grouting liquid seeps on the surface of the structure, which can solve the water leakage problem.
3. After the grouting is completed, the grouting water stop needle can be removed.
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