Study On Dynamic Parameters Of Highway Slope Loess Of Regions Of Multi-frequency Low Magnitudes High Seismic Intensity

The dynamic stability of highway loess slope of region of Multi-frequency low-magnitudes highly seismic intensity can’t be ignored, based on historical events of ground motion of Shanxi, the paper do research on loess gully region of LinFen. first, do great regional survey on loess slope along the highways that had been built and under construction, then selected Lin-Ji highway、Qing-Yin highway、Jing-Kun highway as typical highway loess slope, then, based on field investigating on cutting slope type and established geological structure model, according to reliable similarity theory, Carried out Simulation experiments for different slope types、different geological structure mode, obtained the dynamic response characteristics of highway slope, do ground motion effect analysis of highway loess slope, and provide the basis of input parameters for dynamic triaxial test, finally, analyzed the dynamic triaxial test results.the Data obtained provided theories that Can refer to for evaluation and prevention of dynamic stability of loess slope, the Detailed work is as follows:1. Summed up the research status of field blast ground motion simulating ground motion and dynamic characteristics parameters (acceleration, velocity, etc.) and related research achievements, Pointed out the existing problems of related research, and clarified the necessity of conducting study on dynamic parametric of Loess Slope effects of ground motion.2. Based on the investigation of seismic intensity of LinFen, and the geological structure model, selected Stake for K223+237～K223+400as the test section In Lin-ji highway, divided it into three sections, emplaced the full spectrum seismometers and mobile observation system; Meanwhile, laid strain gauges and Strain rosette at the foot of the layers platform, connected wiring terminals of strain gauges and Strain rosette to a dynamic strain gauge by wires,so, did ground vibration test to simulate the earthquake,whose intensity is Ⅲ-Ⅳ. According to the speed time curve、acceleration time curve、the maximum vibration acceleration (including horizontal and vertical)、the maximum velocity (including horizontal and vertical)of each measuring point Monitored, and the strain date in loess slope caused by ground motion at horizontal and vertical, showed that:the Biggest impact part of loess slope under ground motion in the regions of Multi-frequency low-magnitudes highly seismic intensity is above the middle; characteristic of Seismic waves are affected by explosion source variable、site conditions and geological structure, etc; Site conditions affect the propagation of seismic waves, which is called amplification effect, the softer the site conditions, the greater the amplification effect; and displacement’ amplification effect is the most obvious, then speed, acceleration is the weakest.3. Used the acceleration time curve obtained through Site ground vibration test as the loading parameters in dynamic triaxial experiment,then carrid out30groups dynamic triaxial experiment for Malan loess (Q3) and LiShi loess (Q2), then, analyzed dynamic constitutive relation、damping ratio and dynamic elastic modulus of loess, showed out that:Under Sinusoidal cyclic loads, dynamic constitutive relation of is still Affected by the internal structure of loess、 moisture content、the preconsolidation pressure、void ratio, ect;under the same Dynamic load, if Dynamic elastic modulus(Ed)is greater, cohesion dynamic ofloess (Cd)is higher, the dynamic friction angle ((pd) is lower;and lishi loess(Q2)’ Initial dynamic elastic modulus is higher than Malan loess(Q3)’s, Lishi loess(Q2)80～150Pa Malan loess(Q3)25～100kPa; Lishi loess(Q2)’s Mean value of dynamic elastic modulus is lower than Malan loess(Q3)’s, Lishi loess(Q2)10～20kPa、Malan loess(Q3)10-30kPa;through fitting the dynamic strain(εd)-Damping Ratio(λd) curve of Malan Loess (Q3) and Lishi loess (Q2) obtained that:the growth rate dynamic damping ratio of Malan Loess (Q3) is0.1998,Lishi loess (Q2)’s is0.1285.4. Summaried The research work of the text, and proposed further study work.