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Numerical and field investigation for the stability analysis of a powerhouse cavern in dolomitic limestone
Published in Vladimir Litvinenko, EUROCK2018: Geomechanics and Geodynamics of Rock Masses, 2018
N. Houshmand, K. Shahriar, H. Zarei, A. Kamali
Underground infrastructures stability of rock masses is of significant elements in geotechnical engineering, in both design and construction stages (Barla et al, 2008). The main objective of this study is to evaluate the effect of support system on the stability of staged excavation of the powerhouse cavern in dolomitic limestone. Determining the strength parameters of rock masses and analysis of rock stability are some of the fundamental subjects in rock mechanics (Singh, 2005). As an empirical failure criterion for rock, Hoek-Brown failure criterion has been widely used in rock tunnel engineering, rock slope engineering, and other fields (Wang et al, 2017). However, empirical methods do not provide the stress distributions and deformations around the cavern (Gurocak et al. 2007). At present, a variety of numerical methods are available for stability analysis of rock masses (Abdollahipour, 2012). In overall, displacement, stress, and strain are easy to acquire using numerical calculations. Displacement is a vital parameter in engineering design and construction. The effective parameters including GSI, disturbance factor, discontinuities and rock mass characteristics, overburden depth, and coefficient of lateral pressure are considered as the input parameters to predict the displacements and stresses which may result in instability. It is suggested that for stability analysis of caverns 3D simulation utilize, as the structure of these excavations is complex.
Numerical and field investigation for the stability analysis of a powerhouse cavern in dolomitic limestone
Published in Vladimir Litvinenko, EUROCK2018: Geomechanics and Geodynamics of Rock Masses, 2018
N. Houshmand, K. Shahriar, H. Zarei, A. Kamali
Underground infrastructures stability of rock masses is of significant elements in geotechnical engineering, in both design and construction stages (Barla et al, 2008). The main objective of this study is to evaluate the effect of support system on the stability of staged excavation of the powerhouse cavern in dolomitic limestone. Determining the strength parameters of rock masses and analysis of rock stability are some of the fundamental subjects in rock mechanics (Singh, 2005). As an empirical failure criterion for rock, Hoek-Brown failure criterion has been widely used in rock tunnel engineering, rock slope engineering, and other fields (Wang et al, 2017). However, empirical methods do not provide the stress distributions and deformations around the cavern (Gurocak et al. 2007). At present, a variety of numerical methods are available for stability analysis of rock masses (Abdollahipour, 2012). In overall, displacement, stress, and strain are easy to acquire using numerical calculations. Displacement is a vital parameter in engineering design and construction. The effective parameters including GSI, disturbance factor, discontinuities and rock mass characteristics, overburden depth, and coefficient of lateral pressure are considered as the input parameters to predict the displacements and stresses which may result in instability. It is suggested that for stability analysis of caverns 3D simulation utilize, as the structure of these excavations is complex.
Numerical analysis
Published in Duncan C. Wyllie, Christopher W. Mah, Rock Slope Engineering, 2017
The most common failure criterion for rock masses is the Hoek–Brown failure criterion (see Section 4.5). The Hoek–Brown failure criterion is an empirical relation that characterizes the stress conditions that lead to failure in intact rock and rock masses. It has been used successfully in design approaches that use limit equilibrium solutions. It also has been used indirectly in numerical models by finding equivalent Mohr– Coulomb shear strength parameters that provide a failure surface tangent to the Hoek–Brown failure criterion for specific confining stresses, or ranges of confining stresses. The tangent Mohr– Coulomb parameters are then used in traditional Mohr–Coulomb type constitutive relations and the parameters may or may not be updated during analyses. The procedure is awkward and time-consuming, and consequently there has been little direct use of the Hoek–Brown failure criterion in numerical solution schemes that require full constitutive models. Such models solve for displacements, as well as stresses, and can continue the solution after failure has occurred in some locations. In particular, it is necessary to develop a “flow rule,” which supplies a relation between the components of strain rate at failure. There have been several attempts to develop a full constitutive model from the Hoek–Brown criterion: for example, Pan and Hudson (1988), Carter et al. (1993) and Shah (1992). These formulations assume that the flow rule has some fixed relation to the failure criterion and that the flow rule is isotropic, whereas the Hoek–Brown criterion is not. Recently, Cundall et al. (2003) has proposed a scheme that does not use a fixed form of the flow rule, but rather one that depends on the stress level, and possibly some measure of damage.
Geomechanical characterisation of discontinuous greywacke from the Wellington region based on laboratory testing
Published in New Zealand Journal of Geology and Geophysics, 2022
Marc-André Brideau, Christopher I. Massey, Jonathan M. Carey, Barbara Lyndsell
Laboratory testing programmes can both characterise the material properties as well as provide critical estimates of the sample strength, but only at the core/sample scale. The Hoek-Brown failure criterion (Hoek and Brown 2019), is one of the most widely adopted approaches to estimate the rock mass strength at the outcrop/site scale. This method relies on the true intact rock strength, for example, the intact strength of the greywacke without discontinuities (e.g. Rowe 1980; Read et al. 1999; Stewart 2007), the mi factor (Read et al. 1999), and an estimate of the Geological Strength Index (GSI; Hoek and Brown 2019) for the site.
Analytical and numerical assessment of a preliminary support design – a case study
Published in Cogent Engineering, 2021
Sylvanus Sebbeh-Newton, Shaib Abdulazeez Shehu, Prosper Ayawah, Azupuri A. Kaba, Hareyani Zabidi
Hoek and Brown (1980) developed the Hoek-Brown failure criterion as one of the non-linear criteria for defining the strength of rock mass. The failure criterion is generally recommended for intact rocks and moderately to heavily jointed rock masses (Hoek and Brown, 2019). The Generalised Hoek-Brown constants (mb, s, and a) were determined using the following equations;