| Along with our country urbanization, development and production of construction projects are increasingly frequent. In project construction process of excavation of earthwork mostly stripped topsoil, surface soil in soil and water loss caused by the problems in the process of storage is becoming more and more serious. And the factors affecting the loss is complex, loss of strength, erosion characteristics of different conventional soil erosion, and few studies for stockpiling topsoil rule at present. Therefore, the research and development projects stockpiling overburden soil erosion rule helps rationally designed to prevent and control measures, the development of scientific and effective prevention and control work of soil and water loss. Brown soil in shenyang area of this research unsoiled as the research object, through to the outdoor runoff plot simulated rainfall test, the test set 5 storage time (new accumulation,3 months,6 months,9 months,12 months), three stockpiling earthwork quantity (0.26,0.5,12.2 m3), three kinds of rainfall intensity (0.64,1.05,0.64 mm/min), the effects of storage time, stockpiling earthwork quantity and the influence law of rainfall intensity on stockpiling topsoil soil loss. Tracking index stockpiling overburden soil physical and chemical properties and the apparent morphology variation characteristics, analysis of stockpiling table crops and sediment volume change trend and the differences of the influence of various indicators, identify different stockpiling earthwork quantity and the relationship between the soil loss, as the research area of stockpiling topsoil provide scientific theoretical basis for prevention and control of soil and water loss. The main results were as follows:(1) Stockpiling surface soil physical and chemical properties index and apparent characteristics change with storage time increased remarkably. Stockpiling surface soil bulk density, vegetation coverage rate with the increase of storage time showed a trend of increasing; Porosity, stockpiling overburden height, slope length, slope with the increase of storage time showed a trend of decline; Aggregate and organic matter content showed a trend of decrease in stockpiling 3 months ago, after showed a trend of increase. Stockpiling 3,6,9 and 12 months compared with the new accumulation, three groups of stockpiling surface soil bulk density were increased by 8.8%,16.1%,23.5%,28.8%; Porosity were decreased by 11.7%,19.7%,25.9%,30.5%; Aggregate content were decreased by 24.6%,14.3%,10%,5.1%; Organic matter content were decreased by 42.7%,37.1%,27.1%,15.1%. Three groups of stockpiling topsoil vegetation coverage in depot 3,6,9 and 12 months were 33%,49%,67%, 49%,35%,48%,67%,48%,26%,41%,63%,70%. Three groups of stockpiling overburden height were decreased by 10.7%,20.7%,29.1%,41.6%; Slope length were decreased by 9.3%,15.7%,22.9%,35.6%; Three groups of stockpiling surface soil slope every 3 months 1 DHS. Variance analysis showed that the storage time had a great impact on the vegetation coverage, and other factors were not reached significant level.(2)Under the condition of three kinds of rainfall intensity, with extension of rainfall, surface runoff increase first after flat trend, table crops sediment increase first and then the final stable trend. With the increase of storage time, significant changes in soil loss of topsoil, the decreasing trend. Under the condition of 0.64 mm/min rainfall intensity, compared with the new accumulation, three groups of stockpiling topsoil stockpiling 3,6,9 and 12 months when the runoff volume decreased by7.7%,17.5%,23.5%,30%; Total sediment yield decreased by15.1%,29.9%,39.3%,42.5%. Under the condition of 1.08 mm/min rainfall intensity, runoff amount is accumulated new reduced by 10.7%,22.5%,32.1%,38.1%; The total sediment yield were reduced by 17.5%,42.6%,1.7 times、2.4 times. Under the condition of 1.52 mm/min rainfall intensity, runoff amount is accumulated new reduced by 14.2%,20.1%,24.5%,27.6%; Total sediment yield decreased by 18.1%,28.8%,35.9%,1.8 times.In the same storage stage, with the increase of rainfall intensity, soil loss of stockpiling topsoil significant difference.1.52 mm/min rainfall intensity when the amount of runoff are respectively 0.64,2.3,2.1,1.08 mm/min; Total sediment yield are respectively 0.64,2.1,1.2, 1.08 mm/min. Variance analysis showed that the rainfall intensity for stockpiling topsoil has significant effects of soil and water loss.(3)Based on the influence factors of the influence of soil loss of stockpiling topsoil principal component analysis, the results showed that the vegetation coverage is the main factors influencing the soil loss of stockpiling topsoil. The vegetation coverage and stockpiling surface soil runoff correlation coefficient is 0.887, and the sediment yield the correlation coefficient is 0.914, that illustrate the impact of vegetation on sediment yield is more significant.(4)Through the heap of soil and water loss and soil regression analysis showed that the amount of soil loss of pile soil and correlation coefficient of the whole above 0.9, high goodness of fit. Stocks in six months the rain under the condition of strong, pile soil and runoff amount the highest correlation coefficient, is 0.9997, significantly related. Heavy rain under the condition of strong accumulation in the new period, the total amount of pile soil and sediment correlation coefficient is the largest,0.96 correlation significantly.That under the condition of high intensity rainfall, the greater the amount of pile soil, the greater the increase amplitude of soil loss. |
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