Soil Erosion And Slope Stability Analysis Of Conical Deposits With Different Slope Lengths Under Simulated Rainfall Conditions

In order to study the slope erosion process under the rainfall condition of the conical accumulation of the production and construction project,and to analyze the change process of the slope stability under the rainfall condition,this paper takes the self-made simulation accumulation platform of Yangling Soil and Water Conservation Field Science Experiment Station as the research object,and adopts the artificial rainfall simulation in the field.The method of combining test and analysis,designed 3 slope lengths(3m,4m,5m)and 4 rain intensities(1.0mm/min,1.5mm/min,2.0mm/min,2.5mm/min),and explored the The characteristics of runoff and sediment production and the hydrodynamic process of the conical engineering accumulation under different slope lengths were analyzed,and the slope stability of the accumulation under different rainfall infiltration conditions was analyzed by using the limit equilibrium method.The following main conclusions are drawn:(1)The slope runoff rate of the conical engineering deposits increases first and then tends to be stable with the duration of rainfall.Both slope length and rainfall intensity have an impact on the runoff rate,and the runoff has a very significant correlation with rainfall intensity(P<0.01),the rain intensity factor is greater than the slope length factor.The relationship between the erosion rate and time of the conical engineering deposits can be expressed by a binomial with an opening downward.The erosion rate of conical engineering deposits increases with slope length.The partial correlation analysis of cumulative sediment yield was significantly correlated with rainfall intensity and slope length(P<0.05).(2)The flow velocity of the conical engineering deposits is affected by the combined effect of rainfall intensity and slope length(P<0.01).The characteristics of the correlation degree between flow velocity and runoff and sediment production parameters are: rainfall intensity(I)> denudation rate(Dr)> runoff rate(Q)> slope length(L).The relationship between soil denudation rate and various hydrodynamic parameters is: water flow power(ω)>unit energy(E)of the water-passing section> water flow shear force(τ)> unit water flow power(P),which is determined by the average denudation rate The coefficients are 0.95,0.93,0.86 and 0.85,respectively.In contrast,the correlation between the average value of each hydrodynamic parameter and the average erosion rate is better than the correlation between its instantaneous value and the instantaneous erosion rate under various slope length conditions,indicating that the average value of each hydrodynamic parameter can be better Predict the slope erosion rate.The correlation coefficient between erosion rate and various hydrodynamic parameters ranged from 0.67 to 0.83.Except rain intensity and water flow shear force were significantly correlated with erosion rate(P<0.05),the other parameters were extremely significantly correlated(P<0.01).(3)The Morgenstern-Price(M-P)method was used to calculate the slope stability safety factor of 5m,4m and 3m,which were 5.04,6.04 and 9.53 respectively,and the stability safety factor decreased by 36.67% and 16.61% for every 1m increase in slope length.Under the test conditions,the distribution characteristics of pore pressure on the slope surface of the accumulation at 15 min,30min and 45 min basically did not change when the rainfall intensity was 2.0 and 2.5mm/min.The moisture reached saturation before the rainfall lasted for 30 minutes,and the rainfall had no effect on the pore pressure distribution of the slope after 30 minutes.When the rainfall intensity is 1.0mm/min,the distribution characteristics of pore pressure on the slope of the accumulation are different at 15 min,30min and 45 min,and the water on the slope continues to infiltrate after 30 min of rainfall.Under the same rainfall intensity,the increments(slopes)of pore pressure per unit time at different slope positions are similar.The closer it is to the top of the slope,the greater the change(increase)of the pore water pressure during the rainfall process,and the saturation state is first reached near the toe of the slope,and gradually spreads up along the slope.The variation characteristics of the safety factor of the engineering accumulation slope under different rainfall conditions are different.Generally speaking,the safety factor decreases with the extension of the rainfall duration.The greater the rain intensity,the faster the slope safety factor declines.Under the test conditions,the safety factor of the slope is much larger than the critical value,there is no danger of landslide,and the slope is in the state of rill erosion.