Bayesian identification of soil strata in London Clay

Selection of site-specific regression model for characterization of uniaxial compressive strength of rock

“…UCS can also be obtained from indirect tests such as point load test, tensile strength and rebound hardness number. The point load strength ðIs 50 ð Þ Þ has been found to be an efficient index in estimating UCS [6][7][8][9][10][11]. Broch and Franklin [6] explained that the need for a relationship between Is 50 ð Þ and UCS dated back to the period after development of the point loading method.…”

“…The point load strength ðIs 50 ð Þ Þ has been found to be an efficient index in estimating UCS [6][7][8][9][10][11]. Broch and Franklin [6] explained that the need for a relationship between Is 50 ð Þ and UCS dated back to the period after development of the point loading method. This is because it is not always possible to extract proper cores for sampling purpose in highly weathered rocks [12,13], also when there are time and resources constraints.…”

“…The required testing apparatus is light and usually portable, and more importantly, the test are inexpensive. Different studies have shown, however, that there is no single regression equation relating Is 50 ð Þ to UCS for all rock types [12,[14][15][16]. Many authors have correlated UCS with Is 50 ð Þ in the past, this has brought about many regression equations.…”

“…Many authors have correlated UCS with Is 50 ð Þ in the past, this has brought about many regression equations. For example, Broch and Franklin [6], Chau and Wong [15], Yasar et al [17], Heidari et al [18] and Tugrul and Zarif [19] among others have come up with different regression models between UCS and Is 50 ð Þ . With equations and conversion factors in literature varying a lot, it is clear that there is no unique regression equation which can be used even for the same type of rock.…”

“…This leads to the need to have a rational method of selecting the most appropriate model for a specific site/deposit. Approaches in the past have always relied on both Is 50 ð Þ and UCS test data to generate regressions [6][7][8][9][10][11][12][13][14][15][16][17][18][19] and to evaluate different regressions for a specific site/deposit. However, if the concerned rock is weak or thinly bedded or densely fractured, most times there are difficulties in preparing the rock samples for laboratory compression test.…”