Study On The Stability Of Daxiangshan Red Beds Landslide Of Yunnan Province

Red Beds are the terrigenous clastic sedimentary strata which is red in appearance. Red Beds have a softening, disintegration, water loss shrinkage, cracking and other special projection characteristics, which are easy to slip typically.During the rainy season; the Red-bed region will have large number of landslide disasters frequently.On the basis of analyzing the special engineering properties and mechanism of red bed-type landslides and studying on the status of the red-bed landslide at home and abroad and the current common analysis methods of the landslide stability, this dissertation studes daxiangshan red-bed landslide of yunnan province. First of all, based on the results of in-suite investigation, analyzing the engineering geology of the region and the basic characteristics of the landslide; indentifying that the issues affecting factors of the landslide stability is rainstorms and earthquakes.The evolution process of the landslide experiences the formation phase of the ancient landslide and the Nicun River, the disappearance phase of the upstream landslide lake and the instability phase of accumulation material.The failure mechanism is summarized as plastic flow-slip-crack.And then according to the main influencing factors, the SARMA and FLAC methods are selected.The calculation is given considering the self-weight,rainstorm,earthquake,and other conditions or combinations.Finally,with the topography & geological features of the geological section, the corresponding section of landslide stability is calculated and summary of results are given. Proposals and measures of prevention and treatment are also given.The results have shown that the stability of ancient-landslide is poor and prone to sliding failure, which is in good agreement with the actual phenomenon. At present, the stability of the source region of the landslide is good, but an earthquake or heavy rainfall will hometremendous impact on it.Landslide will threat to the lives and property of the villagers, so the control measures must be taken.The stability of the landslide's accumulation zone is not enough, and the measures should be taken to prevent the slided rock and soil to plug the normal circulation of the Nicun River.Studies have found that red-bed landslide easily brings multi-level and multi-period sliding,which has several sliding surfaces.And the sliding surfaces are not only or may not be the interface layer of the geotechnical.So,in calculating the similar landslide stability, it is proposed that the stress state and sliding shapes should be reproduction truly by FLAC method at first. And then identify the potential sliding surface through the distribution of plastic zones, which can be used for the SARMA method.The results of this calculation will be more conform to reality and easy to be compared, summarized up.