... convergence being higher than the horizontal one. It is thus of interest to evaluate the effect of flexible support composed of compressible wedges and of the final concrete lining on the closure evolution. Also, extensometers measurements and the stresses on the temporary support are analyzed in different...

... (the more difficult to reproduce the overall observations). The computed convergences (and their ratio) and plastic zone extensions are consistent with the in-situ observations. GENERAL LAYOUT Within the perspective of deep geological radioactive waste disposal, the French National Radioactive Waste...

... lining can be rarely designed following the so-called resistance principle. The state of the art suggests approaching the lining design by allowing the development of the necessary convergences to adequately reduce the rock load (yielding principle). In this paper, a new steel element (HiDSte), yet...

... an unsupported length depending on the unconfined compressive strength, the primary stress state, and scale effects in heterogenous rock. With increasing deformations softening from peak to residual strength may occur due to loss of confinement. The axisymmetric convergence behaviour is described by the Fenner...

... ABSTRACT: In deep excavations, mechanical instabilities may appear, inducing damage to the rock mass. These instabilities may be difficult to identify but are inferred as convergence of the walls over time. This magnitude and evolution may provide valuable information for tunnel stability...

... the impact of creep-induced displacement during excavation, a simulation-based methodology, i.e . a viscoplastic model combining the two-component power model and the ubiquitous-joint model, is proposed. The time dependent parameters were calibrated using the back analysis from the convergence measurement...

... ABSTRACT: Simplified 2D analysis of ground support interaction using the convergence-confinement method, although useful in preliminary stages of tunnel design, may be inadequate for complex situations which necessitate 3D numerical simulations with high computational efforts and costs...

... between experimental measurements and numerical predictions, indicating the accuracy of the implemented creep law. INTRODUCTION Deep excavation in squeezing grounds for tunnel engineers normally implies large sometimes excessive tunnel convergences. The development of such deformations usually takes...

...). With the excavation of disposal sites the stress state of the host rock is disturbed. Due to creep, this stress fluctuation decrease over the time, leading to deformations in the host rock. The excavated cavities will converge over a long time scale. By taking such long time scales into account the predicted...

... Abstract In the underground construction of tunnels, high precision of convergence and settlement measures are necessary, and the employment of the total station can attain this goal. The resultant errors of the precision of the total station are evaluated, considering its linear and angular...

... studied for last 18 years with the monitored data. Instrumentation program include measurement of convergence of high walls, load on the support systems with load cells and instrumented bolts. Selection of instruments were based on importanat paramaters required for the design. The data analysis...

... convergence numerical lac du bonnet granite upstream oil & gas du bonnet granite aperture interaction consideration Rock Mechanics for Natural Resources and Infrastructure Development Fontoura, Rocca & Pavón Mendoza (Eds) © 2020 ISRM, ISBN 978-0-367-42284-4 Sobol sensitivity analysis based...

... metals & mining rockburst journal criteria gold mining malan convergence napier stope excavation tabular excavation reservoir characterization southern african institute deformation tabular stope south africa increment criterion rock mechanic reef johannesburg...

... of the entry during driving and longwall retreat phases. Extensive field data including entry convergence, rock bolt loads, and change of pillar stresses were obtained in the Pingshu coal mine, China. A careful analysis of these data shows that the influence zone of the front abutment load can reach as far...

... for hard and massive limestones, convergence confinement for shear prone mudstones, and time dependent creep modeling for salt bands. Tailored ground support types specific to the anticipated behaviors and environmental conditions within the shaft were engineered based upon the expected outcomes. During...

... of convergence monitoring at various underground mine sites in Australia, Canada, Indonesia and South Africa. The results provide the analytical capabilities whilst providing the coverage and functionality of observational methods. This technique is fundamentally changing the way that ground deformation...

... structural geology metals & mining convergence decay excavation reservoir characterization reservoir geomechanics diederich strength artificial intelligence underground space technology formulation deformation underground excavation canadian geotechnical journal tunnel rock...

..., Democratic People’s Republic of Korea. 1 Introduction Tunnel convergence is one of the issues that affects the performance of the tunnels both during the excavation and afterwards. The stability state of the underground structures can timely be known by monitoring the change of surrounding rock mass...

... of a drift following the direction of the major in situ horizontal stress. The evolution of the stress and strain tensors around drifts are calculated by applying an elliptic convergence function on the drift wall. Two failure criteria are then verified for the induced damage. An equivalent strain...

... while mining a 375 m (1,200 ft.) wide longwall face. A field monitoring and numerical modeling study was performed to develop data. Field measurements consisted of roof-to-floor convergence and rectangular rosettes in the immediate roof. Numerical modeling consisted of constructing a 3-D structural...