The state of stress in solid rock with a horizontal working with stowing

The state of stress present in an elastic half-plane contact problem, where one or both bodies is subject to remote tension has been investigated, both for conditions of full stick and partial slip. The state of stress present near the contact edges is studied for different loading scenarios in an asymptotic form. This is of practical relevance to the study of contacts experiencing fretting fatigue, and enables the environment in which cracks nucleate to be specified.

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Effect of the Rock Stress on the Water Jet Cutting Performance

Rock Mechanics and Rock Engineering ◽

10.1007/s00603-021-02508-w ◽

2021 ◽

Author(s):

Battista Grosso ◽

Valentina Dentoni ◽

Augusto Bortolussi

Keyword(s):

Numerical Models ◽

Step Function ◽

Water Jet ◽

The State ◽

Cutting Performance ◽

Lagrangian Analysis ◽

State Of Stress ◽

Water Jet Cutting ◽

Cutting Rate ◽

Available Technology

AbstractUnderground quarrying is rarely adopted for granite extraction due to the difficulties in the implementation of traditional technologies (drilling and explosive). As alternative to drilling and explosive, the combination of diamond wire and water jet seems to be the most promising available technology. The cutting performance achievable with the water jet technology depends on the operative parameters, the material characteristics and the state of stress within the rock massif. To assess the effect of the state of stress on the cutting rate, laboratory tests have been performed with an oscillating water jet machine on granite samples subjected to a static load. The stress distribution in the layer of rock to be removed has been evaluated by numerical simulation with the FLAC code (Fast Lagrangian Analysis of Continua). The correlation between the results of the cutting tests and the numerical models of the rock samples has been inferred. Starting from a conceptual model, which theoretically describes the relationship between the cutting rate and the stress, a step function was defined that indicates the ranges of stress where predefined values of the cutting rate are workable.

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Sub-Level Stoping in an Underground Limestone Quarry: An Analysis of the State of Stress in an Evolutionary Scenario

Archives of Mining Sciences ◽

10.1515/amsc-2016-0015 ◽

2016 ◽

Vol 61 (1) ◽

pp. 199-216 ◽

Cited By ~ 1

Author(s):

Marilena Cardu ◽

Sergio Dipietromaria ◽

Pierpaolo Oreste

Keyword(s):

Numerical Models ◽

The State ◽

In Situ Tests ◽

Future Scenario ◽

Limestone Quarry ◽

Geomechanical Properties ◽

State Of Stress ◽

Upper Level ◽

Pillar Structure

Abstract The aim of this study was to evaluate the state of stress of a „voids-pillar“ structure excavated by means of the sub-level stoping method in an underground limestone quarry near Bergamo (Italy). Both the current structure of the quarry (i.e. the rooms exploited till now) and a possible future scenario were analysed using the (FDM) FLAC 2D code. The quarry has been in operation since 1927; at present, exploitation is carried out underground via the sub-level stoping method. Exploitation involves two levels, with 5 rooms on the upper level and 9 rooms on the lower level. After analysing data obtained from laboratory and in situ tests carried out on rock samples and natural discontinuities, the geomechanical properties of the medium, knowledge of which is essential in order to establish the parameters that must be included in the numerical model, were evaluated. The implementation of three numerical models made it possible to study both the present conditions of quarry exploitation and the evolution of the exploited rooms, as well as a possible expansion involving a third level of rooms. Using the results obtained regarding the stress-strain present in the pillars, a potential change in room geometry was proposed aimed at reducing the stress state inside the pillars, decreasing plasticity and increasing overall quarry safety.

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