| As a world-class super project,the Three Gorges Project has largely alleviated the flood problems and hidden dangers that have existed in the Yangtze River valley since ancient times in China,and effectively ensured the safety of people’s lives and property.However,due to the normal impoundment of the Three Gorges Reservoir,the periodic fluctuation of the water level in front of the dam has formed a large area and a long distance fluctuation area along the reservoir area.The fragile ecosystem in the water-level-fluctuation area,coupled with seasonal and periodic water level drops,makes the environmental problems particularly prominent and affect a wide range.However,the protection and restoration technology for the water-level-fluctuation area of the reservoir is not mature yet.Porous concrete has the advantages of high strength,large porosity,good durability and so on.It can be used as the base for plant growth and form ecological slope protection in the water-resistant area together with water-tolerant plants.Based on the traditional slope protection technology,this paper uses shotcrete to protect the slope in the water-level-fall area of the reservoir,in order to restore its ecology.The main research results are as follows:(1)Reservoir area down slope and construction conditions,is required for the preparation of porous concrete jet performance and lower resilient rate,is obtained by experimental study,when there is no sand porous concrete aggregate particle size control at about 12 mm,porosity 25%,water-binder ratio of 0.38,adding 8% cement quality styrene butadiene rubber latex,and 3% cement quality of the preparation of flexible polypropylene fiber additive injection type porous sand concrete rebound rate is minimal,at 20%.(2)The physical,spray and mechanical properties of the sprayed porous concrete prepared by the test were tested and analyzed from the microscopic perspective.Determination of injection type of porosity of porous concrete is 28%,squirting the 7d compressive strength of porous concrete to 9 mpa,28 d compressive strength measurement of 11 mpa,after 50 times of freeze-thaw cycle,specimen average mass loss rate of 6.4%,the compressive strength loss rate reached 6.0%,the resistance to sulfate erosion test specimens,after 56 d erosion corrosion resistance coefficient is0.78.(3)By scanning electron microscope,infrared spectrum experiment and the analysis of the water COD testing specimen microstructure and ecological performance,after mixing ratio optimization of porous concrete is more advantageous to cementing material and aggregate contact surface to carry on the hydration reaction,make inside the block is more compact,the existence of the effective porosity of porous concrete makes concrete to plant growth provides the basic may,styrene butadiene rubber latex and flexible polypropylene fiber mixed block in durability experiment was carried out with more excellent durability than ordinary concrete,plant growth,according to the test of admixture added to make effective porosity were promoted,The plant growth density and condition are good. |
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