... ABSTRACT The application of conicl PDC teeth to vibratory percussion drilling technology is expected to break deep hard rock efficiently and improve drilling efficiency. In this paper, the characteristics of conicl diamond tooth cutting and hard rock under percussion are investigated. Firstly...

... ABSTRACT Axial-torsional coupled percussive drilling (ATCPD) is a practical technique for creating volumetric breaking patterns and increasing rate of penetration (ROP) of hard rocks. Our paper focus on numerical investigations on ATCPD process. We employed a continuous-discrete coupling...

..., in general, tend to overestimate this critical strength parameter in hard rocks. Alternative approaches are therefore to be developed that are more accurate, reliable, robust and more suitable to hard and brittle rock-like solids. This paper, first, reviews some of the widely accepted testing techniques...

... ABSTRACT: The development of a constitutive model for hard rock goes hand in hand with conventional experiments, which provide information about the intrinsic failure properties of the material. To date most models are calibrated and validated using the macro stress-strain responses from...

... ABSTRACT: In order to reflect effectively the temperature influence on the long-term stability of surrounding rock of deep underground cavern, the triaxial creep tests of deep hard rock under different temperatures were carried out based on an important hydropower station. According...

... of a roller disc (low wear rate) with the effectiveness of a drag tool (low cutting forces). Even though various realizations of the undercutting concept and actuated cutters exist in equipments designed to mechanically excavate hard rocks, the rock failure mechanism and its influencing factors are still...

... construction, the TBMs were operated in different modes in soft ground, mixed-face ground and hard rock. The damaged cutter house and cutters were replaced by accessing the cutterhead through a vertical shaft ahead of the TBM after ground treatment. Due to the engineering means and methods, the tunnels were...

... ABSTRACT: Post-peak mechanical properties of rock have important significance to reveal the mechanism of rock deformation, damage and fracture. Based on the conventional triaxial compression test of hard rock of the Tieshan mine, including marble, homogenic migmatite, banded migmatite, gneiss...

... Abstract The Particle Flow Code (PFC) is a useful tool for simulating the failure behavior of hard rocks. The introduction of clump logic into the PFC modeling has made it possible to better reproduce the brittleness characteristic of hard rocks, namely, the large difference between...

... Abstract: The Particle Flow Code (PFC), a simulation code based on the distinct element method (DEM), is an effective numerical tool for simulating the failure process of hard rock. By introducing contact- and parallel-bond and clump logic, the code has become better able to express...

... ABSTRACT: The bonded-particle model (BPM) consisting of parallel-bonded disks or spheres suffers from the limitation that if one matches the unconfined-compressive strength ( ) of a typical hard rock, then the direct-tension strength ( ) of the model will be too large. This limitation can...

... ABSTRACT: In the design of rock structures such as tunnels and underground caverns, a continuity analysis considering the nonlinearity of rock has been used in many cases. On the other hand, the mechanical and hydraulic behavior of hard rock is governed by discontinuities of various sizes...

... failure criterion, the rock dilation is assumed to remain as a constant when the rock mass is deformed. In many numerical analysis tools [11-14], the default value for dilation angle is often zero for all the nonlinear constitutive models. Reservoir Characterization hard rock dilation angle model...

... beneath located hard rock mine workings, since: (i) due to stress relaxation, generally considered as a positive phenomenon, this layer is able to relieve stress concentrations within its own and the adjacent rock volume, however, due to the associated load transfer process the layer may develop...

... ABSTRACT : To verify the feasibility and efficiency of rotary-percussive drilling assisted by waterjets in very hard rocks, experiments on the performance of Polycrystalline Diamond Compact (PDC) cutters resisting different combined loads of static thrust, impact, cutting and waterjets...

... ABSTRACT : The objective of this work is to propose a constitutive model in order to describe coupled plastic damage behaviour of partially saturated concrete and hard rocks. Plastic behaviour is characterised by using two yield surfaces respectively for stress controlled and suction...

... 1974, Cundall et al. 1994). More recently, researchas shown that deep stopes in hard rock undergo significant time-dependent deformation (Malan 1998). The improved understanding of the time-dependent rock response provides a firm foundation for the assessment of different mining rates or multiple shift...

.... Reservoir Characterization metals & mining reservoir geomechanics Upstream Oil & Gas Engineering geomechanics research centre hard rock selection mechanism Ground Control mechanics research new initiative research chair Toronto Queen canadian rock mechanics research excavation rock...

... improvement, is an accurate model of hard rock cutting. Research undertaken at the Centre Mines Infrastructure (CMI) of the Ecole Nationale Supérieure des Mines de Paris (ENSMP) has shown that the compressive failure of brittle rock under the action of a pick is a combination of two fundamental modes: shear...

... for excavating hard rock. Having identified the need for a mobile rock excavating tool, Caterpillar has introduced the D9L Impact Ripper. This new concept shatters previous ripping limitations by combining the weight of a large crawler tractor and the increased traction provided by a resilient undercarriage...