The Research On Seismic Design Of Excavation Slope In Soft Rocky Ground Area In Western Yunnan

There are many earthquakes in our country, The landslides, collapse cause by earthquakes are quite common.Especially in the area which BaoTeng highway pass through in our western country, it is in the largest earthquake zone of Yunnan:Tengchung - Kengma earthquake zone,which its basic magnitude isⅦgrade and it is the largest earthquake zone of earthquake disaster of Yunnan Province.The earthquake in this area is great in intensity and high frequency,it brings great influence to the highway security of slope excavation side.The Yunnan red bed contains soft rocks which is very special. It has weak water permeability,strong water affinity,and easy to soften when meets the water (or inflation), easy to break up (or contraction) when dehydrates, the intensity is low.it is one kind of rock which project nature is extremely bad.The majority of BaoTeng highway pass through this area, the security of slope excavation side is extremely easy to receive the influence by the rock layer nature, and this highway entire line to be in the Tengchung - Kengma earthquake zone, therefore,it is very necessary to do the research on seismic resistance of excavation slope in soft rocky ground area in west Yunnan.Through investigations which the Yunnan western area earthquake zone history, the Yunnan laterite level soft crag forms and so on. This paper analyzed theoretically the project nature of earthquake and the influence of the red bed soft rocks to the highway security of slope excavation. Finally drew support from the FLAC3D software,it analyzed simulatly the area red rock soft crag under magnitude earthquake function, the gradient slope,height,the kind of side slope, and the earthquake incidence angle, earthquake wave intensity rank, excavated side stable. Calculated the max stable height which the gradient slope is 1:0.33, 1:0.5, 1:0.75, 1:1, 1:1.2 under theⅦgrade earthquake, this has provided certain reference for the earthquake resistance design to excavated slope in this area.At present the influence of the seismic force to the side slope is mainly concentrates on the magnification degree which side slope to the earthquake acceleration, the speed,and the seismic force,but this paper is mainly through utilizes the FLAC3D software, used the intensity discount law, analyzed the influence to the the side slope safety coefficient,then determinates the stability of side slope under the seismic force, this has provided one new method for the analysis side slope under the seismic force stability, also had certain model function to other local project earthquake resistance design research.This paper is supported by the major social development project in Yunnan Province 2009—"Baoshan to Tengchong expressway technological and cultural demonstration project".