The Study Of Laboratory Model Test Of Slope Under Rainfall Infiltration Condition

China is a country with many geologic hazards,and among that slope hazard occupies a great proportion.After entering the new century,China’s economy continues to grow at a high level.Engineering construction projects have been launched everywhere in recent years,and that lead to the trend of geological hazards increasing.Among many factors causing the landslide,rainfall especially heavy rainfall,is the most significant factor.The infiltration process changes the water content in the slope,and causes soil stress,pore water stress(etc.)varieties,which lead to the decline of soil shear strength and may affect the slope’s stability.The main research contents are as follows:(1)Designing a rainfall infiltration model test,through the analysis of slope water content,pore water stress,soil stress and slope deformation under different monitoring points,and different rainfall time conditions.Concluding the change regulation of rainfall infiltration on slope.Designing a monitoring system by using FBG sensor and multichannel fiber grating demodulator.And applied this system to the slope rainfall infiltration model test.Using LabVIEW,designed a PC-end monitoring software,which could collect data and do some simple analysis.(2)The rainfall infiltration test data indicates that at the beginning of rainfall infiltration,lots of silt on the slope surface is washed away,and because of the rainfall infiltration amount is less than the silt erosion amount at the time,the slope’s load decreases,and the inner soil stress of slope starts to decrease.But as the rainfall infiltration continues,the inner soil stress of slope starts to increase.Showing that the scale of rainfall infiltration is much bigger than the silt erosion.The slope’s load keeps rising till the rainfall infiltration ends.After the rainfall,the inner soil stress is higher than the initial stress.And the pore water stress has no obvious change in beginning of rainfall infiltration,as the progress continues the value of pore water stress increases gradually,and the unsaturated soil of top part is becoming saturated,as the saturated region expands downward,the soil’s moisture of below part increases until it becomes saturated.The model test data also indicates that the deformation value of the slope’s top part is much bigger than other part,in the absence of any slope-protection measures.(3)Taking the rainfall infiltration model test as a background,and using two methods-whether considering matric suction or not to simulate the rainfall infiltration progress by PLAXIS.Collecting the simulation result from the initial pore pressure field,slope seepage field,pore pressure and saturation’s distribution during the rainfall infiltration progress and other aspects,and comparing the result with the model test result,finally got the conclusion that for the non-groundwater model slope,it is more reasonable to simulate without considering the matric suction.