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http://dx.doi.org/10.12652/Ksce.2013.33.1.207

Short-Array Beamforming Technique for the Investigation of Shear-Wave Velocity at Large Rockfill Dams  

Joh, Sung-Ho (Chung-ang University)
Norfarah, Nadia Ismail (Chung-ang University)
Publication Information
KSCE Journal of Civil and Environmental Engineering Research / v.33, no.1, 2013 , pp. 207-218 More about this Journal
Abstract
One of the input parameters in the evaluation of seismic performance of rockfill dams is shear-wave velocity of rock debris and clay core. Reliable evaluation of shear-wave velocity by surface-wave methods requires overcoming the problems of rock-debris discontinuity, material inhomogeneity and sloping boundary. In this paper, for the shear-wave velocity investigation of rockfill dams, SBF (Short-Array Beamforming) technique was proposed using the principles of conventional beamforming technique and adopted to solve limitations of the conventional surface-wave techniques. SBF technique utilizes a 3- to 9-m long measurement array and a far-field source, which allowed the technique to eliminate problems of near-field effects and investigate local anomalies. This paper describes the procedure to investigate shear-wave velocity profile of rockfill dams by SBF technique and IRF (Impulse-response filtration) technique with accuracy and reliability. Validity of the proposed SBF technique was verified by comparisons with downhole tests and CapSASW (Common-Array-Profiling Spectral-Analysis-of-Surface-Waves) tests at a railroad embankment compacted with rock debris.
Keywords
rockfill dam; shear-wave velocity; surface-wave method; seismic analysis; beamforming technique;
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