| Under the rapid development of civil engineering and water conservancy engineering in China,more and more attention has been paid to the research of slope engineering safety,and vegetation slope protection is an important research direction at present.Vegetation slope protection is to protect the slope using plants to contain water and fix soil,which can not only meet the requirements of stability,but also have good ecological benefits.Relevant studies at home and abroad show that plants play a significant role in preventing soil erosion and improving slope stability.However,the existence of vegetation roots would change the permeability of soil,increase the infiltration of rainwater,the water content and pore water pressure of slope,and reduce the shear strength of soil.It is still controversial which of the strengthening effect of root system on soil strength and the preferential flow effect of macropores produced by root system has greater influence on slope stability.Taking back water slope of Culai Reservoir in Culai Town,Daiyue District,Tai’an City,Shandong Province as the test site,this paper studies the rainfall infiltration law of the back slope of earth-rock dam with three slope protection types of plain soil,turf and honeysuckle by means of artificial rainfall simulation in the field.Based on Geo-Studio finite element software SEEP/W,SIGMA/W,SLOPE/W module,the stability safety factor of the back water slope of earth-rock dam with different plant slope protection types under different rainfall conditions is simulated to study the influence of rainfall conditions and vegetation slope protection types on the stability of the reservoir back water slope by considering the influence of vegetation root system on permeability and soil strength.The main conclusions are as follows:(1)Rainfall infiltration law of backwater slope of earth-rock dam under different rainfall intensityThe change trend of soil volume moisture content of plain soil,turf and honeysuckle slope protection with time is basically the same,which first increases,then fluctuates near the peak value,and then decreases to a stable state;With the increase of soil depth,the ability of rainwater infiltration gradually weakens,the response time of soil moisture rainfall is delayed,and the change of soil moisture content gradually decreases There is a positive correlation between rainfall infiltration depth and moisture content change of plain soil,turf and honeysuckle slopes and rainfall intensity.With the increase of rainfall intensity,the response time and peak time of soil moisture content change of different slope types are advanced.The depth of rainfall infiltration and the change of soil volume moisture content gradually increase.(2)Rainfall infiltration law of backwater slope of earth-rock dam with different vegetation slope protection typesUnder 90mm/h rainfall intensity,compared with plain soil slope protection,the water content of turf slope protection and honeysuckle slope protection has a rapid increase process with time,and the maximum change of volume water content is larger.The maximum change of soil volume water content from large to small is: turf > honeysuckle > plain soil;The response time of soil volume moisture content change of honeysuckle slope protection lags behind that of turf slope obviously.(3)Influence of rainfall on stability of backwater slope of earth-rock damAfter rainfall,the slope safety factor would continue to decline,reach the minimum at a certain time,and then show a slow upward trend.There is a positive correlation between the decline rate of slope safety factor of different slope protection types and rainfall intensity.The greater the rainfall intensity,the greater the decline rate of slope safety factor.(4)Influence of slope protection types on stability of backwater slope of earth-rock damUnder the same rainfall conditions,the slope safety factors of different slope protection types are honeysuckle slope protection,turf slope protection and plain soil slope protection from large to small,and the decline rate of safety factors is plain soil slope protection,turf slope protection and honeysuckle slope protection from large to small.The above conclusions show that under certain rainfall conditions,honeysuckle slope protection can improve the stability of the back water slope of earth-rock dam,and verify the feasibility of planting honeysuckle slope protection on the back water slope of earth-rock dam. |
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