On the imaging of stress changes in particulate media: an experimental study

1994 ◽  
Vol 31 (2) ◽  
pp. 215-222 ◽  
Author(s):  
J.C. Santamarina ◽  
B. Potts
Keyword(s):  
Experimental Study ◽  
Wave Propagation ◽  
Retaining Wall ◽  
Geophysical Methods ◽  
Simulated Data ◽  
The State ◽  
Surface Load ◽  
State Of Stress ◽  
Stress Changes ◽  
Velocity Changes

The stiffness of soils depends on the state of stress. Therefore, the velocity of wave propagation can be used to assess the state of stress and its changes. Indeed, given sufficient data, measurements can be inverted to produce a tomographic image of the stress field. A preliminary study of this approach was conducted with simulated data and is summarized briefly. Results of an experimental study are then presented. Three common geotechnical systems were tested: a footing, a moving surface load, and a retaining wall. Calculated velocity changes are compared with predicted velocity changes, with stress changes being estimated by classical analytical solutions. Good agreement is found in the three cases. The need for accuracy in travel-time measurements, difficulties in tomographic imaging, and the propagation of uncertainty from inverted velocities to stresses are discussed. Key words : geophysical methods, tomography, wave propagation, stress, retaining wall, footings.

scholarly journals Mining-Induced Seismicity during Development Works in Coalbeds in the Context of Forecasts of Geomechanical Conditions

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6675
Author(s):  
Dariusz Chlebowski ◽  
Zbigniew Burtan
Keyword(s):  
Induced Seismicity ◽  
Geophysical Methods ◽  
Small Diameter ◽  
The State ◽  
Engineering Practice ◽  
Mining Operations ◽  
Rockburst Hazard ◽  
State Of Stress ◽  
Mining Induced Seismicity ◽  
Hazard Level

Mining-induced seismicity in the area of development works and proper mining operations is one of the major determinants of the rockburst hazard level in underground mines. Rockburst hazard assessment in Polish collieries is performed by a variety of mining and geophysical methods, including seismic and seismoacoustic techniques, borehole surveys, small diameter drilling, rock strata profiling and analyses of geomechanical properties of rocks, geological structure and geological mining conditions. In the case of zones particularly exposed to potential hazards, it is recommended that analytical or numerical forecasts of the state of stress in the vicinity of workings should be used already at the stage of planning of mining operations. This study summarises the comparative analysis of seismic test data and analytical forecasts of the state of stress in five selected headings in one of the burst-prone collieries within the Upper Silesia Coal Basin in Poland (USCB). As regards the seismic data, duly defined quantitative indicators and energy criteria of the registered seismic activity are recalled in the assessment of rockburst hazard level during the roadheading operations. Analytical simulations utilise a developed geomechanical model and stress–strain relationships stemming from the principles of elastic media mechanics. From the standpoint of mining engineering practice, interpretation of results obtained by the two methods reveals how effective analytical models will be in prognosticating or verification of rockburst hazard conditions.

scholarly journals Half-plane contacts subject to remote tension

2021 ◽  
pp. 030932472098844
Author(s):  
Nils Cwiekala ◽  
David A Hills
Keyword(s):  
Contact Problem ◽  
Half Plane ◽  
Asymptotic Form ◽  
Fretting Fatigue ◽  
The State ◽  
Partial Slip ◽  
Practical Relevance ◽  
Plane Contact ◽  
State Of Stress ◽  
Plane Contact Problem

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.

scholarly journals Effect of the Rock Stress on the Water Jet Cutting Performance

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.

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

2016 ◽  
Vol 61 (1) ◽  
pp. 199-216 ◽  
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.

scholarly journals ESTIMATING PURITY AND ENTROPY IN STABILIZER STATE EXPERIMENTS

2010 ◽  
Vol 08 (01n02) ◽  
pp. 325-335 ◽  
Author(s):  
HARALD WUNDERLICH ◽  
MARTIN B. PLENIO
Keyword(s):  
Quantum Information ◽  
Measurement Data ◽  
Simulated Data ◽  
The State ◽  
Graph State ◽  
Graph States ◽  
Underlying Graph ◽  
Moderate Number ◽  
Full State ◽  
State Tomography

Many experiments in quantum information aim at creating graph states. Quantifying the purity of an experimentally achieved graph state could in principle be accomplished using full-state tomography. This method requires a number of measurement settings growing exponentially with the number of constituents involved. Thus, full-state tomography becomes experimentally infeasible even for a moderate number of qubits. In this paper, we present a method to estimate the purity of experimentally achieved graph states with simple measurements. The observables we consider are the stabilizers of the underlying graph. Then, we formulate the problem as: "What is the state with the least purity that is compatible with the measurement data?" We solve this problem analytically and compare the obtained bounds with results from full-state tomography for simulated data.

Sign in / Sign up

Export Citation Format

Share Document