Digitalization of mechanical and physical properties of Singapore Bukit Timah granite rocks based on borehole data from four sites

Abstract

The Bukit Timah Granite (BTG) formation is widely distributed in the central and northern parts of Singapore Island. The BTG rocks in the formation vary from granite to granodiorite. Several hybrid rocks and dykes are also present in the BTG. The granite is in various states of fracturing and weathering, ranging from residual soils to intact, unweathered fresh rock. This paper presents some mechanical and physical properties of Singapore BTG rocks, based on data from the Factual Geotechnical Reports of more than 200 boreholes from Downtown Line stage II (DTL2) sites of Cashew, Hillview, Bukit Panjang and Beauty World. The variations of the parameters, including the unconfined compressive strength (UCS), the point-load strength index (Is50), the Cerchar abrasivity index (CAI), and the slake-durability index are derived from laboratory tests on samples from borelogs of different depths. The empirical correlations between the UCS and Is50 and between the CAI and the strength parameters (UCS and Is50) are derived and validated against the commonly adopted equations. Statistical information, including the average values, the standard deviations, and the coefficients of variation, are provided for these parameters. These statistics provide a useful reference for numerical simulations and future projects involving BTG rocks.