Sains Malaysiana 45(2)(2016): 185–193

Use of Ultrasonic Velocity Travel Time to Estimate Uniaxial Compressive

Strength of Granite and Schist in Malaysia

(Penggunaan Masa Perjalanan Halaju Ultrasonik untuk Menganggarkan Kekuatan Mampatan

Sepaksi Granit dan Syis di Malaysia)

Goh Thian Lai*¹, Abdul Ghani Rafek², Ailie Sofyiana Serasa¹, Azimah Hussin¹

& Lee Khai Ern³

¹Geology Program, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia

²Department of Geosciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh,

Perak Darul Ridzuan, Malaysia

³Institute for Environment and Development (LESTARI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan, Malaysia

Received: 5 May 2015/Accepted: 20 August 2015

ABSTRACT

The uniaxial compressive strength (UCS) is one of the most common mechanical parameters required in geotechnical engineering to characterize the compressive strength of rock material. Measurements of UCS are expensive, time consuming, destructive and thus, not favorable in the presence of limited samples. Therefore, a simple yet practical application is needed for the estimation of UCS. This research presents two correlations to predict UCS values for granite and schist by using ultrasonic velocity travel time (tp) from ultrasonic tests. The validity of the practical approach presented in this research is confirmed based on the strong correlations developed from the experimental tests conducted. For the entire data set, the correlation between UCS and ultrasonic velocity travel time was expressed as UCS = 217.2 e-0.016(tp) for granite and UCS = 1110.6 e-0.037(tp) for schist and the coefficient of determination (R2) value for both granite and schist is 0.93. These correlations may be useful for applications related to geotechnical engineering designs.

Keywords: Empirical correlation; ultrasonic velocity travel time; uniaxial compressive strength

ABSTRAK

Kekuatan mampatan sepaksi (UCS) merupakan salah satu parameter mekanik paling lazim diperlukan dalam kejuruteraan geoteknik untuk mencirikan kekuatan mampatan bahan batuan. Pengukuran menggunakan UCS adalah mahal, tempoh yang panjang, merosakkan dan tidak sesuai jika sampel adalah terhad. Oleh yang demikian, penggunaan aplikasi yang ringkas tetapi praktikal diperlukan untuk anggaran UCS. Kajian ini membentangkan dua korelasi untuk meramalkan nilai UCS granit dan syis dengan menggunakan masa perjalanan halaju ultrasonik (tp) daripada ujian ultrasonik. Pengesahan pendekatan praktikal yang dikemukakan dalam kajian ini disahkan berdasarkan korelasi yang baik yang dibangunkan daripada ujian eksperimen yang dijalankan. Bagi keseluruhan set data, hubung kait antara UCS dan masa perjalanan halaju ultrasonik dinyatakan sebagai UCS = 217.2 e-0.016(tp)untuk granit dan UCS = 1110.6 e-0.037(tp) untuk syis dan nilai pekali penentuan (R2) bagi kedua-dua granit dan syis adalah 0.93. Korelasi ini mungkin berguna untuk aplikasi yang berkaitan dengan reka bentuk kejuruteraan geoteknik.

Kata kunci: Kekuatan mampatan sepaksi; korelasi empirikal; masa perjalanan halaju ultrasonik

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*Corresponding author; email: gdsbgoh@gmail.com