Study On The Response And Stability Mechanics Of Loess Slope In Environment Of Strong Earthquake

Science its special geological structure background, the regions covered by loess in china which include the south-north Seismic belt, north of china seismic belt and QI-Lian Seismic belt, is one of the regions with the maximum frequency of earthquake occurred in our country, and has the massive history strong earthquake records. For the reason of earthquake vulnerability, subsidence and liquation of loess, the history earthquake induced numerous of seismic geological disaster, especially the 1920 Hai Yuan earthquake, trigger a lot of loess landslides.In this paper, the XiJi-HaiYuan-GuYuan region in south of Ning Xia Province has been chosen as a investigation target area, and the distribution, characters and failure model, development mechanism of the landslide induced by earthquake has been studied, and then, the seismic data of this regions has been collected to build the attenuation relation of ground acceleration, and gained the seismic wave. Based on these, the dynamic constitutive equations, seismic subsidence and liquation of loess, the dynamic response and dynamic stability of loess slope has been studied.Some main innovative ideas are got as follows in this paper:(1) in the summary, with the centralized appearance and huddled together distribution characters, the earthquake landslides in the target area are mainly happened in the low, gentle slope and incised strongly, thin and weak loess side slope, and these landslides has specifically movement aspect, liquefaction phenomenon, and has streamline and undee physiognomy characters.(2) Based on its failure mechanism, the failure modeles are defined as the softened-sheared model, the liquefaction-flow model, and the falling model, hysteretic landslide model, and then, the reason and mechanism of landslide happened serriedly in the target regison are owed to its location, material and physiognomy, and predominant frequency of seismic wave.(3) the earthquake history data are collected, and the attenuation relation of ground acceleration induced by earthquake are gained by the methodes of statistic, regression and transform analysis, in succession, the artifical earthquake wave are produced after the earthquake fatalness analysis, which are used to research the loess dynamic triaxial test, dynamic response and dynamic stability loess slope.(4) after the dynamic triaxial test, the dynamic constitutive equations are gained, and the seismic subsidence mechanism of loess are disclosed, and its expression are revised, and gained the formula of subsidence in condition of seismic wave, as well as the effection of superexcellent frequency, maximum value and aspect of seismic wave, and the consolidation ratio, moisture content etc, and more farther, the por water pressure increase model of loess in seismic condition are gained, and the effect of shear strength by reason of earthquake wave acted on the sample.(5) based on the attenuation relation of ground acceleration and dynamic constitutive equations, the dynamic response of loess slope are studied as well as the effect of maximum value, superexcellent frequency and aspect of seismic wave, active fault.(6) when forecast the stability of loess slope in earthquake condition, a seismic wave which exhibit the geological and seismic structure background, epicenter and spread medium character should be chosen to obtain the dynamic response and test parameters, and the increase value of pore water pressure, the soften of loess framework shear strength and the seismic subsidence should be take into account.