| The source of the South Jingyang area since the last century since 70 s,in order to improve the grain yield of the agricultural irrigation area,caused a large-scal slope landslide and intensified the trend.Landslide not only caused huge economic losses to the local residents,but also caused a lot of casualties.Through the field survey found that,in a certain distance from the plateau edge within the scope of the distribution of some through long cracks,a large number of scholars have found that these cracks and slope landslide has great links,rainwater and irrigation water will enter into the soil a long the cracks,then slowly penetrate into the soil.In this paper,the South Jingyang plateau as the research object,through field investigation,field test,laboratory test and numerical simulation method to study the law of surface water infiltration in soil,mechanical properties of EPS light soil,and filling in cracks,to slow down or landslid eoccurrence.The main research contents are as follows:(1)Through field survey and investigation,understanding the development of slope cracks,record the irrigation time of villagers winter irrigation,irrigation water head etc.(2)According to the duration of the irrigation time and irrigation head of the villagers test,have an in-situ permeability test in different soil on the slope.The test shows the saturated permeability coefficient of soil,the maximum penetration range in the horizontal direction and vertical direction of soil after the end of the experiment.Put the saturated soil sample in the pressure plate apparatus and gradually pressurized dewatering test,permeability range,obtaind by in situ experiment of saturated permeabilit y coefficient and the VG model fitting SWCC curve and parameters of soil.(3)Studied the saturated permeability coefficient of the horizontal and vertical soil samples under suction of 50kPa、100kPa、200kPa、300kPa、400kPa、500kPa、600kPa,and net confining pressures were 50 kPa,100kPa and 200 kPa.The results show that :the horizontal and vertical permeability coefficient ratio is larger when the confining pressure is small(≤200KPa),the ratio is gradually reduced when the confining pressure increases,the ratio close to 1 when confining pressure is larger(500k Pa),and the time of bubbles removal from the soil with the increase of confining pressure is positively correlated.(4)Through orthogonal test,obtained the mixture ratio of the EPS light soil ratio both meet in side of applicability and economy.Research the wet deformation of EPS lightweight soil,control suction were 50 kPa,100k Pa,200 kPa,through the consolidated drained shear test by using three triaxial test instrument.The results show that:(1)under the same net confining pressure,when the strain is the same,the larger the suction s is,the greater the stress is needed when shearing;under the same suction s,the greater the net confining pressure is,the greater the stress is needed when shearing;(2)For the stress-strain curve,the curve increases nearly a straight line,then the strain increases and the stress increases slowly,finally,the stress continues to increase and stress decrease.(3)A simplified model is given for the stress-strain curve of shear stage.(5)To study the effect of cracks on the slope landslide,using GEO-SLOPE software modeling and analysis by existing data and field survey.The results showed that the crack distance of slope position is certain,with the increase of crack depth,reduce the safety factor of stability;Crack depth is certain,with the distance of slope distance closer,stability coefficient is small;Obtained the critical state line of crack depth and crack to the slope distance when maintenance of slope stability.(6)To study the effect of cracks on the slope landslide,On the basis of the existing model,put the loess and EPS light soil into the model cracks respectively.According to the irrigation time of the villagers,obtained variation of safety coefficient by simulated irrigation for one year and thirteen years. |
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