... be analyzed with numerical methods and back analysis to assess the ground behavior and system response. The cases of three large size TBM tunnels are presented: (1) a twin-tunnel (each tube is 15.1 m diameter), in clay and clay marl. (2) A twin tunnel (each tube is 15.6 m diameter) in claystone and clayish...

... change in the ground. It has been observed that the pore pressure field is affected on a distance of about four diameters in the vicinity of the tunnel face (e.g. Armand et al. 2014, Vaunat et al. 2013, Giger et al. 2015). During the excavation progress, overpressure can be observed before the passage...

... BACKGROUND 2.1 Water-intake tunnels The water-intake tunnels of Taishan nuclear power station are located between Yaoguzui and Dajin islands in China, and they are 4330 m long and 9 m in diameter. The overburden of tunnels varies from 11 m to 29 m, and the pillar between the two tunnels is 29.2 m on average...

... (T01 to T16 ) is provided on Figure 1a. The maximum diameter of the intersection is 8.8 m and the total linear of the intersection is about 27 m. At the MHM URL, it has to be notice that gallery section, larger than 6 m in diameter, cannot be excavated in full section for technological and supply...

... of the horizontal principal minor stress have been excavated with a diameter of 9 m. The main goal was to compare the response of the rock mass formation around this drift with respect to the one observed in drifts excavated with same orientation but with a diameter of 5 m. In situ observations showed...

... fiber reinforcement metals & mining shotcrete excavation diameter flexural strength en14651 Rock Mechanics for Natural Resources and Infrastructure Development Fontoura, Rocca & Pavón Mendoza (Eds) © 2020 ISRM, ISBN 978-0-367-42284-4 The use of fiber reinforced shotcrete as rock support...

... upstream oil & gas reservoir geomechanics diameter structural geology reservoir characterization specimen sandstone corvio sandstone hydraulic fracturing fracture toughness specimen geometry blanco mera granite scb specimen sandstone 0 experimental investigation pseudo-compact...

... specimen geometry prediction sand control diameter anisotropy sandstone figure 7 Rock Mechanics for Natural Resources and Infrastructure Development Fontoura, Rocca & Pavón Mendoza (Eds) © 2020 ISRM, ISBN 978-0-367-42284-4 Novel true triaxial apparatus applied to the study of sand mass...

... of Land and Resources, Xi an, Shan Xi, China ABSTRACT: Six numerical calculation models with different charge diameter were established by the soft of Ansys to analyse explosive pressure and shock attenuation laws. The results show that the peak displacement of particles obeyed the exponential attenuation...

... to split the specimen into two similar halves. The crack initiates at the notch tip and propagates along the diameter of the specimen (i.e. the ligament plane). 2.2 Experimental setup The testing equipment consists in a high-stiffness frame equipped with a 50 kN push/pull load cell, two LVDTs and a crack...

... and Technology, Tokyo, Japan ABSTRACT: A series of in-situ and laboratory triaxial compression tests were conducted for a wide range of specimen size, the diameters of specimens, d = 20 400 mm. Based on the tests results, this study focuses on scale effects on pre-failure mechanical characteristics and post...

...) for measuring the fracture toughness of mode I (tensile) fractures. A CCNBD specimen is a Brazilian disc with a chevron or V-shaped notch cut along the core diameter using a circular saw from both sides in the middle of the specimen. By applying a compressive load across the circumference of the disc, a crack...

... of the wells is selected taking into account the condition of the output of the measuring base (end of the wells) for the zone of influence of mine working. The size of such zones is 2-3 diameters of mine working. In our case, the length of the wells in the pair is 5 and 8 m, the measuring base is 3 m...

... stiffness strength ortlepp diameter Rock Mechanics for Natural Resources and Infrastructure Development Fontoura, Rocca & Pavón Mendoza (Eds) © 2020 ISRM, ISBN 978-0-367-42284-4 Tensile mechanical properties of the flexible bent rockbolt and its application in the deep roadway Bin Wang, Zeyang Guo...

... lithologies in a mining company. Both fleets are large and drill above seven inches in diameter in an open-pit mining. Three main parameters were covered: Physical Availability, Productivity and Specific Consumption of diesel, which will be studied in order to define a better way of allocation of equipment...

... of the failure cones between 70 and 240 mm of radius, for anchor lengths (La ) between 46 and 114 mm, and hole diameters (Dh ) between 15 and 18 mm. The geometric ratio La Dh used by the author ranged from 2.6 to 7.2, testing mortars of uniaxial compressive strengths ( c ) between 2.3 and 7.3 MPa. According...

... and a reliable tensile strength could be obtained when the ratio of outer ring diameter to specimen diameter, r1/R, is 0.62±0.08, the ratio of inner ring diameter to specimen diameter, r2/R, is 0.45±0.12, and the ratio of inner ring diameter to outer ring diameter, r2/r1, is 0.64±0.06. Tensile strength results...

... of the caverns as well as maintain the plastic zone in its place. The rock support consists of mesh/steel fiber reinforced shotcrete together with fully grouted rock bolts (bar anchors or threadbars). The length and diameter of the rock bolts varies in different parts of the caverns. In PHC roof, rock bolts...

... characterization. Our laboratory has available two different circular saws for preparing the irregular blocks that usually come from the nearby mines. A medium-sized circular saw (Controls 55C0210/D) with a 500 mm diameter diamond cutting disc (Figure 1a), and a small circular saw (Controls 45-D0536) with a 350 mm...

... referred to as µ(I) rheology, as the work of Pouliquen (Pouliquen, 2002). As the variation of grain diameter might change the inertia number I and also the basal friction, a fragmentation law is included, fol- lowing the work of Longo et al. 2019. 3.3 µ(I) based models The friction coefficient µ - please...