Pocket type separated strata grouting material for controlling surface subsidence, preparation and grouting method thereof

Abstract

The invention provides a pocket type separated strata grouting material for controlling surface subsidence. The pocket type separated strata grouting material is composed of a main material and water in the following ratio, the main material consists of cement, fly ash and an admixture, wherein the water-ash ratio is 0.7-0.8, the ratio of fly ash to cement is 0.8-0.9, and the admixture accounts for 3%-5% of the total amount of the main material. The pocket type separated strata grouting material provided by the invention has the characteristics of good pumpability, low bleeding rate and layering degree, short setting time, high strength and stability, small grout dosage, single-hole grouting total amount of about 13m<3>, and low cost. The invention also provides a preparation method and grouting method of the pocket type separated strata grouting material. The preparation method has the advantages of simple operation and low cost. The grouting method can flexibly control the separated strata grouting time, fundamentally limits the development of separated strata, ensures that key strata do not break, and reaches the purpose of controlling surface subsidence. Through the isolation function of the pocket, slurry does not leak to cause environmental pollution.

Description

technical field [0001] The invention belongs to the technical field of coal mine surface subsidence control, and in particular relates to a bag-type separation layer grouting material for controlling surface subsidence and a preparation and grouting method thereof. Background technique [0002] According to statistics, my country's mining industry occupies and destroys about 34,000 hm2 of land each year, of which the annual ground subsidence caused by coal mining alone is about 30,000 hm2, and the cumulative amount has reached 500,000 hm2. my country's per capita arable land area is only 1 / 4 of the world's per capita arable land area, and the current land damage is so serious that people must pay enough attention. [0003] At present, the most effective methods to control surface subsidence in coal mining are filling mining and overlying strata separation layer grouting. Compared with layer-separated grouting in filling mining, the investment cost of filling pipeline system...

AI Technical Summary

Problems solved by technology

The separation layer grouting technology also has two problems to be solved urgently: first, due to the influence of mining, the movement of the overlying strata is a dynamic process, and the height and width of the separation layer are constantly changing with the mining. The location and timing of layer grouting is difficult to grasp very well

Once the separation layer is closed during mining, the grouting work cannot continue, which reduces the total amount of grouting and fails to achieve the expected effect in controlling surface deformation; second, the separation layer grouting material generally uses fly ash It is a mortar mixed with water, and fly ash has weak cementation ability. Once the mortar loses water in the separation layer, it is difficult for the consolidated fly ash to ensure sufficient strength to limit the movement of the overlying rock layer and control the deformation of the ground surface. The third is that the water-cement ratio of the separation layer grouting material is generally 2:1, and the water accounts for about 70%. The environment of the working face is adversely affected, and there is even the risk of well flooding

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