Dynamic Properties of Soils at Large Strains in Roorkee Region Using Field and Laboratory Tests

Abstract

The evaluation of the dynamic properties of natural soil deposits is important to study the site response, to predict the ground motion and to proceed to seismic zonation. In this paper, dynamic behavior of soils in Roorkee (India) region has been investigated. The study focuses primarily on four sites: Solani Riverbed site, Bhagwanpur site, Bahadrabad site, and Haridwar site. The soil samples were collected from different depths at these four sites using SPT. Soil samples collected were tested in the laboratory for index properties and subjected to bender element tests to measure the maximum shear wave velocity. Dynamic behavior of soil samples collected from all sites was investigated by a series of cyclic triaxial tests. Strain controlled undrained cyclic triaxial tests were carried out as per ASTM D3999 for determination of dynamic soil properties (i.e., shear modulus and damping ratio). The effects of shear strain (in the range 0.03–2%) on shear modulus and damping ratio have been investigated at different depths. The results show that the variation in shear modulus and damping ratio with shear strain is greater for the samples collected from greater depths as compared to the samples collected from shallower depths. Variation in shear modulus and damping ratio with shear strain were compared with the published literature and found to be in good agreement.