Injection concrete

Abstract

The invention relates to a sprayed concrete which contains cement, sand-stone mixture, steel fiber, accelerating agent and special additive. The special additive is inorganic neutral nano-sized zeolite containing SiO2 and Al2O3 as major chemical components, wherein the weight ratio of water to cement to sand-stone mixture to steel fiber is (8.5-8.6):(16.1-20.0):(69.6-73.5):(1.7-1.8), the special additive accounts for 5-10% the weight of cement, and the accelerating agent accounts for 6-8% the weight of cement. When used in water-rich areas, the sprayed concrete can cure within 1minute and exhibits strength after 10 minutes, the rebound rate of the sprayed concrete is reduced to 7.8% from 15% in the common wet-jetting concrete, the binding strength reaches 3.5 MPa, and the spray thickness is more than 0.3 m at each time. The invention reduces the workload of lining concrete construction and avoids water leakage, and also has the advantages of rapid construction, good flexibility and improvement in working environment inside tunnel.

Description

technical field [0001] The invention relates to shotcrete, in particular to shotcrete in water-rich areas of tunnels. Background technique [0002] In the tunnel excavation process, for safety, the sprayed concrete must also follow closely. However, ordinary sprayed concrete can not be sprayed in the water-rich area at all, and its rebound can reach 95%. The so-called "water-rich area" generally refers to "line, The water outlet section of the tunnel under the condition of "drop-shaped" water, the engineering volume of this kind of construction section is particularly large, usually after the tunnel (hole) is excavated, it is solved by directly installing waterproof boards combined with secondary lining concrete; once the structure appears Water seepage will be further treated by measures such as leak-stopping agent and V-groove buried pipe between construction joints. If grouting treatment is adopted before ordinary concrete is sprayed, the construction period cannot be gu...

AI Technical Summary

Problems solved by technology

If grouting treatment is adopted before ordinary concrete is sprayed, the construction period cannot be guaranteed, and the investment will be increased. With the continuous improvement of sprayed concrete technology, especially the addition of external admixtures and the introduction of imported spraying machinery in the mix design of sprayed concrete With the rapid development of the wet spraying process, there are more and more various external materials that change the quality of the sprayed concrete, such as steel fiber, microfiber, silicon powder, water reducing agent, etc., which solve the problem of spraying concrete support There are many engineering and technical problems in the maintenance, but the proportion design of sprayed concrete suitable for water-rich areas has not yet been found.

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