Study On Pulsating Characteristics And Dynamic Response Of Representative Slopes In Tianshui River Basin

The Loess Plateau in Northwest China is located in the northern part of theNorth-South seismic belt,and there have been many recorded historical earthquakes and strong earthquakes.A large number of representative loess/mudstone structural slopes are distributed in the Tianshui River Basin.The study of its pulsatingcharacteristics and dynamic response is of great significance to the urban planning and urban development of Tianshui.According to the field survey and the measurement data of landslide and natural slope ground fluctuation,the following contents are mainly studied by using therelevant statistical analysis and numerical simulation methods.1.Correlation between loess/mudstone slope and disaster factors.2.The natural vibration characteristics of loess/mudstone landslide and loess/mudstone natural slope,and the relationship between the predominant period of slope body and the factors of slope morphology.3.The seismic response characteristics of loess/mudstone slope with different morphological elements in the river basin and its sensitivity to the morphologicalelements of the slope.The main research results are as follows:1.The main landslides in the River Basin are loess/mudstone compositelandslides.The slope density of the landslides in the basin is 9³8 degrees,especially in the interval of 9²8 degrees,and the high density of slope is 92m³53m,especially the distribution of landslides in the 186m²73m interval is the most concentrated.2.The spectral curves of the Loess/mudstone slope in the River Basin aremainly single peak type,and the outstanding periodic distribution of the slope in the river basin is between 0.2s⁰.4s and the upstream to the lower reaches of the river.The thickness of the Loess slider is the key factor affecting the excellent week period of the Loess/mudstone landslide in the basin,and the landslide excellent cycle isT₁.The one element linear regression formula with the thickness of the d₁ is T₁=0.004d₁+0.136,and the thickness of the loess cover layer is the key factoraffecting the excellent period of the natural slope of the Loess/mudstone in the basin.The linear regression formula of the outstanding period T₀ of the slope and thethickness of the loess cover thicknessof the d0 is T0=0.001d0+0.242.3.The order of the sensitivity of the seismic dynamic response of the Loess/mudstone slope in the river basin to the factors of the slope shape under the condition of weak earthquake excitation is the thickness of the cover layer>the slope>theslope height,and the order of the sensitivity of the seismic dynamic response of the slope to the slope shape under the strong earthquake excitation is the gradient>coverage.The thickness of the layer is higher than the slope.4.There is no high slope effect when the slope height is less than 1/2 incidentwave length under the vertical incidence of the P wave under the vertical incidence of P wave in the river basin,and the acceleration of the slope monitoring point increases with the elevation,and the multiple linear regression formula between theamplification factor and the slope shape factor is?=0.025d₂+0.037?₁+0.015h₁-0.819.