Journal: Rock Mechanics and Rock Engineering

Abbreviation

Rock Mech Rock Eng

Publisher

Springer

Journal Volumes

ISSN

1434-453X
0723-2632

Description

Filters

Reset filters

Search Results

Publications 1 - 10 of 79
  • Stabilitätsberechnung ebener und räumlicher Felsböschungen
    Item type: Journal Article
    Kovári, Kalman; Fritz, Pit (1976)
    Rock Mechanics and Rock Engineering
  • Effects of Creep on Shield Tunnelling Through Squeezing Ground
    Item type: Journal Article
    Leone, Thomas; Nordas, Alexandros; Anagnostou, Georgios (2024)
    Rock Mechanics and Rock Engineering
    The present work aims to improve the reliability of shield jamming and lining damage risk assessment in squeezing ground by analysing the effects of creep on the evolution of rock pressure over time. The study is based on numerical simulations of typical mechanised tunnelling processes, generally consisting of shield advance phases alternating with shorter or longer standstills for lining installation, maintenance, etc. A linear elastic-viscous plastic constitutive model based upon Perzyna's overstress theory is employed, which considers the time-dependency of plastic deformations via a single viscosity parameter. The investigations demonstrate the following: (i) shield loading during advance increases with increasing viscosity under certain conditions, which contradicts the common perception in many existing works that creep is thoroughly favourable for shield jamming; (ii) creep is thoroughly unfavourable for shield loading during long standstills and long-term lining loading, due to the additional viscoplastic ground deformations manifested over time; (iii) the commonly adopted simplifying assumption of continuous excavation with the gross advance rate is adequate only where standstills are very short (e.g., for lining erection during the stop-and-go shield tunnelling process), but otherwise underestimates the shield loading, even in cases of regular inspection and maintenance standstills lasting only a few hours. Two application examples, the Frejus safety gallery and the Gotthard Base tunnel, demonstrate the need to consider creep and the accuracy of modelling tunnel construction by a semi-discrete approach, where only the very short standstills for lining erection are considered via an average advance rate, but longer standstills are explicitly simulated.
  • Creep Versus Consolidation in Tunnelling through Squeezing Ground-Part B: Transferability of Experience
    Item type: Journal Article
    Nordas, Alexandros; Leone, Thomas; Anagnostou, Georgios (2024)
    Rock Mechanics and Rock Engineering
    This paper investigates potential differences between creep and consolidation in mechanised tunnelling through squeezing ground, placing focus on the practical question of using experiences gained from existing tunnels about the required thrust force as a reference for tunnels of different diameter or adjacent tunnels. The investigations focus on two aspects. First, the effect of the tunnel diameter on the risk of shield jamming is examined. The paper demonstrates that larger-diameter tunnels are more favourable in poor-quality ground, while the opposite holds in better-quality ground, as well as in the case of pronouncedly time-dependent ground behaviour due to consolidation or creep. Second, the effect of a tunnel on the required thrust force in a neighbouring tunnel built later is examined. The paper shows that this interaction effect is particularly important in water-bearing ground of low permeability, where the drainage action of the first tunnel induces pore pressure relief and ground consolidation in an extensive area, leading to a remarkable reduction of the thrust force in the second tunnel. Conversely, in the case of creep the interaction is negligible even under extremely squeezing conditions, due to the fundamentally different nature of the purely mechanical rheological processes from coupled hydromechanical processes. The presented investigations into the transferability of experiences are valuable for tunnelling practice, in cases of twin tunnels as well as in situations where a smaller-diameter tunnel is constructed prior to the main tunnel (e.g. a pilot tunnel for exploration, advance drainage or ground improvement), or also the opposite (e.g. upgrade of a road tunnel by later construction of a safety tunnel with a smaller diameter).
  • Geomechanical properties of shear zones in the eastern Aar massif, Switzerland and their implication on tunnelling
    Item type: Journal Article
    Laws, S.; Eberhardt, E.; Loew, S.; et al. (2003)
    Rock Mechanics and Rock Engineering
  • Comparative Study of Nine Intact Rock Failure Criteria via Analytical Geometry
    Item type: Journal Article
    He, Peng-fei; Ma, Xiao-dong; He, Man-chao; et al. (2022)
    Rock Mechanics and Rock Engineering
    The existing comparative studies of intact rock failure criteria do not typically consider the tensile stress zone and failure angle prediction. A new comparative study of nine intact rock strength criteria worth to list them here was performed under the framework of analytical geometry, with respect to their geometric characteristics in different cutting planes of the failure envelopes in three-dimensional space as well as predictive capacities for strength and failure angle. For this purpose, a universal failure angle formula was derived as a guideline to deduce the specific expression for each criterion. The sigma(1)-sigma(3) cutting plane displays two categories of the intact rock failure criteria: overlapping and separate compressive and tensile meridian boundaries. Experimental strength data and failure angle observation of two sandstones under complex compressive stress conditions highlight the failure criteria of Mogi-1967, Mogi-1971, nonlinear unified and Hoek-Brown in terms of strength and failure angle prediction. It is probably the first of its kind to date to evaluate different intact rock failure criteria by relating the failure angle and strength. This innovative comparative work enlightens the future advancement of the intact rock failure criterion with the consideration of the tensile stress zone and failure angle observation.
  • Rock Mechanics Investigations for the Endangered Bristen Road
    Item type: Journal Article
    Bergamin, Stefan; Kirchhofer, Peter; Filippini, Raffaele Lino (2001)
    Rock Mechanics and Rock Engineering
  • Characterization of Hydraulic Fractures Growth During the Äspö Hard Rock Laboratory Experiment (Sweden)
    Item type: Journal Article
    López-Comino, José Á.; Cesca, Simone; Heimann, Sebastian; et al. (2017)
    Rock Mechanics and Rock Engineering
  • Tunnel Face Stability and the Effectiveness of Advance Drainage Measures in Water-Bearing Ground of Non-uniform Permeability
    Item type: Journal Article
    Zingg, Sara; Anagnostou, Georgios (2018)
    Rock Mechanics and Rock Engineering
    Non-uniform permeability may result in complex hydraulic head fields with potentially very high hydraulic gradients close to the tunnel face, which may be adverse for stability depending on the ground strength. Pore pressure relief by drainage measures in advance of the tunnel excavation improves stability, but the effectiveness of drainage boreholes may be low in the case of alternating aquifers and aquitards. This paper analyses the effects of hydraulic heterogeneity and advance drainage quantitatively by means of limit equilibrium computations that take account of the seepage forces acting upon the ground in the vicinity the tunnel face. The piezometric field is determined numerically by means of steady-state, three-dimensional seepage flow analyses considering the heterogeneous structure of the ground and a typical advance drainage scheme consisting of six axial boreholes drilled from the tunnel face. A suite of stability analyses was carried out covering a wide range of heterogeneity scales. The computational results show the effect of the orientation, thickness, location, number and permeability ratio of aquifers and aquitards and provide valuable indications about potentially critical situations, the effectiveness of advance drainage and the adequate arrangement of drainage boreholes. The paper shows that hydraulic heterogeneity results in highly variable face behaviour, even if the shear strength of the ground is constant along the alignment, but ground behaviour is considerably less variable in the presence of advance drainage measures.
  • On the Time-Development of Sulphate Hydration in Anhydritic Swelling Rocks
    Item type: Journal Article
    Serafeimidis, Konstantinos; Anagnostou, Georgios (2013)
    Rock Mechanics and Rock Engineering
  • The Solubilities and Thermodynamic Equilibrium of Anhydrite and Gypsum
    Item type: Journal Article
    Serafeimidis, Konstantinos; Anagnostou, Georgios (2015)
    Rock Mechanics and Rock Engineering
Publications 1 - 10 of 79