FACULTY OF ENGINEERING

Dynamic Soil Stiffness Between WAK, SASW and SCPT Tests

Abstract

This paper describes an experimental investigation for determining the dynamic soil stiffness by applying the principles of WAK (wave-activated stiffness [K]) test analysis, spectral analysis of surface waves (SASW) method and seismic cone penetration test (SCPT). The WAK and SASW tests were performed by applying an impact load on a circular steel plate of 50 cm diameter in vertical direction. A sledgehammer equipped with a dynamic force transducer was used to produce the impact load. The force time signal from the dynamic loading (input) and acceleration time signals from vertical accelerometers (output) were recorded during the tests. The dynamic stiffness of the soil were obtained by considering the soil to be vibrating as a single degree of freedom (SDOF) system. The SCPT was performed by measuring the travel times of body waves propagating between a seismic shear wave source at the ground surface activated at each level and an array of geophones. The dynamic soil stiffness obtained from WAK and SASW tests agreed very well with the SCPT test.

Author

Dr Norazzlina M.Sa’don is a Senior Lecturer in the Department of Civil Engineering, Faculty of Engineering, Universiti Malaysia Sarawak. She is an Affiliate Member of American Society of Civil Engineers (ASCE) and Member of the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE). She obtained her PhD in Civil Engineering from the University of Auckland, New Zealand, MSc in Civil Engineering with Distinction from Cardiff University and BEng with Honours in Civil Engineering from Universiti Malaysia Sarawak. After working as a project engineer in Malacca for six months, she joined UNIMAS in January 2001. She was awarded grants from Kiwi Advanced Research & Education Network and New Zealand Network for Earthquake Engineering Simulation. Norazzlina investigated the inertial response of piles in residual clay and developed a procedure for preliminary design of a single long pile under lateral loading. Her research interests include soil-structure interaction, swelling and shrinkage of expansive soil and stabilization of soft soil.