Engineering Application Research Of The Cemented Sand And Gravel In Alagou Reservoir

Cemented sand and gravel is a new building material, which is a range between sandy gravel and concrete in material composition and mechanical properties. It has greater strength and less post-settlement than sandy gravel, quicker and easier construction and less-cost than concrete. It has lower demand for aggregate, and take advantage of local materials, has minimal impact on the local environment, so it has been applied in many domestic and international hydraulic engineering. However, the domestic research on cemented sand and gravel starts relatively late, mostly used as filling materials for temporary hydraulic engineering projects such as cofferdam. If this material is applied to the permanent dam project, further research must be carried out on the mix design.This paper firstly analyzes 18 group sandy grave grain composition which used in hydroelectric dam in Xinjiang, on this basis, a series of physical properties was be tested, lastly, this article mainly expounds the application of cemented sand and gravel in the Alagou ditch reservoir spillway as the basis filling materials. The main results are as follows:(1) Comprehensive comparison of the sand ratio, gradation discrete degree, aggregate availability and well-graded ratio of the 18 group sandy grave in Xinjiang, it concludes that 100 mm is the best maximum aggregate size.(2) Changing the coarse aggregate and the fine aggregate’s gradation, to explore their impact on strength’s discrete of the cemented sand and gravel, the results show when changing the thickness of the aggregate lonely, there is a certain effect on the strength, but the impact is not large. By testing the cemented sand and gravel test block’s compressive strength under three conservation methods such as standard conservation, conservation of plastic wrap, not curing, it shows that the compressive strength is largest when the test block under the standard curing conditions, but the other two have little difference, suggesting that cemented sand and gravel should be continuous construction engineering without performing sprinkler maintenance procedures.(3) Through orthogonal experiments, three factors-age, cement content and frequency of freeze-thaw were tested to the cemented sand and gravel frost resistance’s impact, it shows that age is the most significant factor affecting frost resistance, followed by the amount of cement and the times of freeze-thaw; Recommend that Cemented sand and overwintering layer should be stopped the construction 14 days prior to the arrival of low-temperature climate, And overwintering layer of the cement content shouldn’t less than 70kg/m3,after construction, the overwintering layer should be immediately covered, and prevent the water from entering.(4) Selecting the cemented sand and gravel as the basis filling materials in the Alagou ditch reservoir spillway, and its construction method references RCC, through testing the VC value, degree of compaction, compressive strength of the test block, and using core boring sampling to retest to control the construction quality, broaden the scope of application of cemented sand and gravel.