The Statistics And Analysis Of Soil Dynamic Parameters

Soil dynamic parameters are important indicators that characterize mechanical property of soils under dynamic action. This dissertation mainly studies the relations between shear wave velocity, dynamic shear modulus, damping ratio and other physical indicators of soils. In soil seismic response of earthquake resistant engineering, shear wave velocity, dynamic shear modulus and damping ratio of soils are the important parameters that must be given. They have direct influence on the seismic ground motion input result on non-rock sites. Therefore, it is important not only to study the relations between shear wave velocity, dynamic shear modulus, damping ratio and other physical indicators of soils but also to determine reasonably and use properly these parameters. Based on the existing results, the following studies are carried out in this dissertation:1. Based on consulting literature and other data, the present studies of soil dynamic parameters are summarized and reviewed briefly in this paper. The measuring methods of these parameters are introduced briefly and main existing problems are analyzed.2. After collecting hundreds of seismic safety evaluation data on non-rock sites, the author sort shear wave velocity, dynamic shear modulus, damping ratio and other physical parameters of soils out and then select about one hundred typical sites with relatively complete data as research data.3. The linear fitting, polynomial fitting and exponential fitting are applied to analyze the relations between shear wave velocity and depth of soils of various types; statistical analysis method is applied to study the relations between shear wave velocity and standard penetration test blow count. The results are satisfactory and have certain application value.4. This paper analyzes the relations among shear wave velocity, depth of soils and standard penetration test blow count by two methods of multiple regression analysis: Vs = a + bH + cNdand Vs = l + mN d + nHNd. Similarly, the relations among shear wave velocity, depth and density of soils are studied by1 12 2Vs = c + aρ? + bHρ?. The results are all satisfactory.5. According to the collected data and using statistical analysis method, the author presents the relations of dynamic shear modulus ratio and damping ratio versus dynamic shear strain for typical soils of central region of Songnen Plain(mainly are Harbin and its neighboring regions). Based on the existing results, the preliminary recommendation value of dynamic shear modulus ratio and damping ratio are given.