Study On Rainfall Infiltration Characteristics Of Rock Slope Of Red Stratum Region In Sichuan Province

Landslide is the most common type of geological hazard in red stratum region in Sichuan Province.Taking the red area of Nanjiang County in Sichuan Province as an example,the heavy rainfall occurred on September 16,2011,which caused a large area of massive geological disasters and a total of 1860 disaster sites in Nanjiang County.Of which,1162 were new disaster sites.In these new disaster sites,Landslides accounted for more than 85%.Landslides of red beds in the distribution of its wide,the number of large,hidden strong,the characteristics of the great harm,had to cause people's attention.For the Nanjiang County red rock mass landslide predecessors have done a lot of research work,which has made great progress.However,for the infiltration of rock mass,because of its anisotropy and difficult to determine the geometric shape of joint fractures,its research is not yet mature,the research methods are mostly theoretical or indoor model,numerical experiments,lack of verification of field examples,the study results of rock mass infiltration in the red stratum region are few,and lack of deeper research on the infiltration of fractured rock mass.Therefore,the study of this kind of landslide caused by rainfall is not deep enough,at least not complete.In view of this,the author takes the rock slope in the red stratum region of Nanjiang County as a typical model to further study the infiltration law of the rock mass in the red stratum region of Sichuan Province,and further reveal the infiltration rule of the rock slope in the red layer area,and provide reference for the disaster prevention and reduction work of the red stratum region.The authors studied the characteristics of rock slopes infiltration in the red stratum region in Sichuan by means of data collection,remote sensing interpretation,field geological survey,statistics,laboratory tests and field tests.The main conclusions are as follows:(1)By analyzing the steep wall direction of Jurassic strata and Cretaceous,the maximum principal stress of the new tectonic movement is 341.63 ° ~ 7.15 °.Through the statistical study area exposed to the surface of the crop,the history of the largest principal stress to 305.7 °.(2)From the results of matrix joint statistics,there are four groups with obvious fissure development: The first set: NE and NW;The second set: NEE direction,NNW direction and NW thrust joint;The third set: NNE and EW;The fourth set: NE direction,NW direction and NW direction joint.According to the results of the matching process,the direction of the main compressive stress is deduced: EW ? NE-SW ? NW-SE ? NNE-SSW,and according to the NNE direction of the new tectonic stress,the NW to the shear joint and the NW joint are under tension,the remaining joints are pressure or compressive.(3)The stress condition of the red rock slope is affected by the later stage effect: the frontier unloading belt and the trailing edge deformation uncoordinated belt become the favorable area of rainfall infiltration.In fact,through the observation,the results show that the rainfall infiltration model can be infiltrated from the surface through the joint,and the rainfall infiltration model includes the continuous trailing edge of the slope,the infiltration of the fissure network and the infiltration of the fissure network.Joint infiltration point infiltration,the central slope of the spike point infiltration,and the slope of the front of a single fracture infiltration or fissure network infiltration.(4)The characteristics of the trailing edge banding infiltration were studied by high density electrical test and field observation,that is,the rainfall was infiltrated through the trailing edge,and the upper part of the upper and lower cracks was saturated first,and the groundwater was infiltrated vertically Mainly,along the weak interlayer uneven horizontal seepage and discharge in the empty space.The infiltration tensor of a fractured rock mass at the trailing edge of the slope is calculated by using the field test,the geological radar and the sampling method.The effect of the water injection test is modified to qualitatively analyze the infiltration capacity of the fissure network,The experimental method and sampling method to calculate the permeability coefficient of the ratio of 0.581.