Norwegian Geotechnical Institute (NGI) Digital Archive
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    1133 research outputs found

    Evolution of the Exmouth-Barrow carbonate margin through the Miocene: Insights from 3D seismic data and field investigations (North West Shelf, Australia)

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    Carbonate margins are records of the palaeoclimatology, palaeoceanography and palaeogeography of continental shelves, and their study can help identify both regional and global palaeoenvironmental changes. This study documents the evolution of the Exmouth-Barrow margin, which records one of the largest ramp to rimmed platform transition documented yet, throughout the Miocene. The research is based on the integration of onshore outcrops, offshore wells and 3D seismic data. The margin evolution can be divided in four main phases, including: (1) progradation of carbonate clinoforms, forming a depositional ramp, during the early Miocene; (2) sabkha development and extensive dolomitization, concomitant with the Miocene Climatic Optimum; (3) formation of a carbonate barrier-lagoon system associated with slope channels during the middle Miocene; and (4) onset of a dominantly siliciclastic sedimentation from the end of middle Miocene onward. Overall, this study illustrates how outcrops and offshore seismic data can be integrated to reconstruct the regional stratigraphic and palaeoenvironmental evolution of a continental margin, with outcrops providing precise but local information, while 3D seismic data allow the basin-scale reconstruction of the palaeolandscape.Evolution of the Exmouth-Barrow carbonate margin through the Miocene: Insights from 3D seismic data and field investigations (North West Shelf, Australia)publishedVersio

    A Simplified Approach to Estimate Anchoring Capacity of Blocky Rock Mass with Pressure Arch Theory

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    In this paper, a simplified method for predicting rock mass resistance against tensile forces from rock anchors (anchor) is presented. The interaction of anchors and rock mass was investigated using three-dimensional discontinuous numerical modelling. Several patterns of rock discontinuities were assumed in the numerical modelling while a single anchor is embedded in it. The numerical results show that the existence of a discontinuity set sub-parallel to the anchor significantly improves the rock mass resistance against the tensile force from the anchors. This phenomenon is due to the rock block interlocking at the sub-parallel discontinuity set. Rock block interlocking generates a zone of stress concentration inside the rock mass which has an arch shape (i.e., a pressure arch), resisting against the anchor's tensile force. The load-bearing capacity of the pressure arch plays a significant role in the resistance of the rock mass against the forces from the rock anchor. A voussoir beam analogy was utilised to study the load-bearing capacity of the pressure arch. A simplified analytical approach was developed to assess the load-bearing capacity of the voussoir beams. Then, it was used in combination with the weight of the mobilised rock mass by the anchor to assess the maximum anchoring resistance of the rock mass (anchoring capacity). The suggested method was calibrated by numerical modelling and relevant published pull-out test results. The technique developed in this paper shows the significance of rock block size, shear behaviour of rock discontinuities, Young's modulus of the rock mass, and uniaxial compressive and tensile strength of the intact rock in anchoring capacity of rock masses.publishedVersio

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    Norwegian Geotechnical Institute (NGI) Digital Archive is based in Norway
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