The Research Of Dynamic Deformation Property Of Loess And Seismic Dynamic Response Analysis For Soil

Loess is a special soil. It spreads around in China, especially the loess in the northwestern region is the most thickest and the most complete. In Northwest loess area in China, which is one of China's quake-prone areas, the seismic activity is frequent. In the current, as large-scale development of the western region is the backdrop, the study of the dynamic property of loess becomes more and more important. Using the general idea for soil dynamics, through field investigation and sampling in Xi'an, in some ways, in control of water content to 12%,16%,20% and wet density control to 1.4g/cm3,1.6 g/cm3,1.8 g/cm3, the author makes the undisturbed soil intoΦ39.1×80mm soil samples, then use the computer-controlled electro-hydraulic servo W3Z-20 soil dynamic triaxial testing system of Chang'an University geotechnical engineering open laboratory to carry through dynamic triaxial test in different consolidation confining pressure, consolidation stress ratio, vibration frequency and vibration wave shape to discuss the laws of the loess dynamic constitutive relationship (mainly the stress-strain relation) dynamic elastic modulus and damping ratio changing with different factors above. The experimental results shows: The strain increases with the increase of stress. When stress is small, the trend of strain increasing with the increase of stress is significant. When the stress reaches a certain value, the trend begins to be eased. Water content, wet density, consolidation confining pressure, consolidation stress ratio, vibration frequency and vibration wave shape are the several major factors which influence over dynamic elastic modulus and damping ratio of loess. With water content and vibration frequency decreasing or wet density, consolidation confining pressure and consolidation stress ratio increasing, dynamic elastic modulus is gradually increasing. In addition, the seismic safety evaluation software Ese and the large general-purpose finite element software Marc are separately managed to carry out the analysis of one-dimensional and two-dimensional seismic dynamic response for soil. Through calculation, the conclusion that one-dimensional and two-dimensional seismic response dynamic analysis for soil are consistent is made.