Using multivariate adaptive regression splines to develop relationship between rock quality designation and permeability

Initial Assessment on Hydraulic Conductivity of Rock Mass and its Size Effect Using Drilling Data

“…1–5, No.10–12, and No. 16–18 segments), whereas the relation by Jiang et al (2009c), Qureshi et al (2014) estimate low hydraulic conductivity. The method proposed by Ku et al (2009) works not well in the intact rock zones.…”

“…Figure 3b shows that the classification of jointed rock mass has been done for 24 segments. The various empirical relations from Jiang et al (2009c), Qureshi et al (2014), Song et al (2014), and Ku et al (2009) is used to estimate the hydraulic conductivity of rock masses, respectively. Clearly, the values of the hydraulic conductivity estimated from the proposed relation (Equation 6) using drilling method are mostly at or slightly lower than those estimate by Jiang et al (2009c), Qureshi et al (2014), Song et al (2014), and Ku et al (2009).…”

“…Empirical models of hydraulic conductivity as a function of the geomechanical index of a rock mass are one of the most commonly used tools with which hydraulic conductivity is studied. Several empirical relationships have been established between hydraulic conductivity and these geomechanical indices (Cha et al, 2006; Jiang et al 2009a, 2009b; Qureshi et al 2014). Using regression analysis, other empirical relationships between permeability and RQD have been established: GSI‐RQD (Öge 2017) and RMR‐RQD (El‐Naqa 2001).…”

“…These results present the effect of geologic factors on the hydraulic conductivity (Achtziger‐Zupančič et al 2017a; Chen et al 2018), considering the discontinuous geometric features (Zhou et al 2018), testing technologies available (Scibek et al 2016), and the scale effect of rock masses (Butler and Healey 1998; Follin and Stigsson 2014; Shapiro et al 2015). Moreover, various statistical methods or empirical equations (Ku et al 2009; Jiang et al 2009a, 2009b; Qureshi et al 2014; Song et al 2014; Chen et al 2016; Öge 2017; Pappalardo 2018) utilizing geomechanical indices (GSI, RMR, etc.) have been widely used to study the effect of lithology, in situ stress, and geologic structure on the spatial variability in the hydraulic conductivity of rock masses.…”

“…Since the flow of fluids occurs primarily along fractures, the permeabilities of intact rock and jointed rock vary widely. Hydraulic conductivity is evaluated based on discontinuous parameters such as fracture frequency, fracture aperture, joint opening, and RQD during field work (Jiang et al 2009a, 2009b; Qureshi et al 2014; Öge 2017; Zheng et al 2020a). In the case of a site with no history of tectonic events and uniform lithology, the hydraulic conductivity decreasing is related to the depth‐wise decreasing in the discontinuous frequency, and the increasing in RQD (Jiang et al 2009c).…”