Extension of excavation damaged zone due to longwall

Extension of excavation damaged zone due to longwall

Excavation Damaged Zone - 2 - Andra

strongly coupled. An unexpectedly extended disturbed zone (both hydraulic and mechanical) due to excavation was observed. The pore pressure and displacement sensors began to register regular variation when the excavation front was still more than 60 metres (i.e. 12.5 tunnel diameters) distant.

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Subsidence Due to Undermining of Sloping Terrain: A Case …

extension of the monitoring was precluded by restricted surface access. At each survey, the vertical and horizontal position of each pin located on the centerline of the panel being mined and between the centerlines of the adjacent longwall panels was measured and recorded. The location of the face position during each survey was also recorded.

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ISME2009- Paper Formatting and Preparation

Due to advancing coal face, a CZ above the longwall face is created and stress field is redistributed; consequently, a triangular damaged zone is created above the gate roadway and an additional loading is applied to coal pillars and EDZ, which causes an extension in EDZ [10, 11].

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Development of excavation damaged zones around a

Request PDF | Development of excavation damaged zones around a rectangular roadway under mining-induced pressure | This paper presents an investigation of the development of …

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Comprehensive evaluation of excavation-damaged zones in

Feb 18, 2016 · Tunn Undergr Space Technol 24(1):1–13 assessment of excavation damaged zone (EDZ) of a rock mass Li SJ, Feng XT, Li ZH (2011) In situ experiments on width and and its application to a dam foundation case. Eng Geol evolution characteristics of excavation damaged zone in deeply 104:254–262 buried tunnels.

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Application of Distributed Optical Fiber Sensing

Feb 22, 2018 · After roadway excavation, the deformation and failure of roadway surrounding rocks typically results in roadway damage or collapse. Conventional monitoring techniques, such as extensometers, stress meters, and convergence stations, are only capable to detect the stress or strain data with the shallow layers of surrounding rocks, and they require arduous manual …

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eng_geol_subsidence_coal_diag

Differential horizontal displace­ments result in a zone of apparent extension on the convex part of the subsidence profile (over the edges of the excavation) whilst a zone of compression develops on the concave section over the excavation itself. Geology and subsidence due to longwall mining. angular distortion implies that damage is

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Coal Operators Conference Papers and Proceedings – Mining

Papers from 2019. PDF. Proceedings of the 2019 Coal Operators Conference, Naj Aziz and Bob Kininmonth. PDF. Development of double shear testing of tendons, Naj Aziz, Guanyu Yang, Saman Khaleghparast, and Travis Marshall. PDF. Ageing effect on the self-heating incubation behaviour of lignite, Basil Beamish, Jan Theiler, and Andrew Garvie. PDF

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SID.ir | JOURNAL OF MINING AND ENVIRONMENTAL

Dec 27, 2021 · Contact Us. Address : No. 1, 4th All, Bahar Ave, Qamushi St, Ashrafi Esfahani Hwy, Tehran, Iran . Post Code : 1461965381 . Tel/fax : +982144265001-4

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(PDF) Hollow Cylinder Tests on Boom Clay: Modelling of

The zone in which major hydro-mechanical modifications occur is called the Excavation Damaged Zone (EDZ) (Davies and Bernier 2005; Tsang et al. 2005). 3 To ensure their efficiency, the models that are expected to be used to predict and characterize the EDZ should be validated under characteristic loadings similar to the ones occurring during

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Expansionary Evolution Characteristics of Plastic Zone in

Factors leading to coal and gas outbursts are complicated, and the accuracy of predicting outbursts remains difficult to achieve. Therefore, coal and gas outburst risk are still a scientific challenge in the fields of mining, geology, safe engineering, and rock mechanics. Theories explaining and predicting coal and gas outbursts associated with restored strain and gas …

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Excavation damage zones - smcoy.fi

The construction-induced excavation damage EDZ CI extends in a drill-and-blast tunnel from 0.1 m to as much as 1.5 m into the rock, increasing permeability by two or three orders of magnitude (Tsang et al., 2005).

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A Geometric Computational Model for Calculation of

Jan 01, 2016 · In this model, the stability of gate roadways are investigated based on loading effects due to EDZ and caving zone (CZ) above the longwall face, which can extend the EDZ size. The structure of GCM depends on four important factors: (1) geomechanical properties of hanging wall, (2) dip and thickness of coal seam, (3) CZ characteristics, and (4) pillar width.

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Ultrasonic sounding and monitoring of the excavation

Under high in situ stresses and high anisotropic stress ratios, the excavation of underground openings generally causes the creation of a disturbed (EdZ: Excavation disturbed Zone) and/or damaged (EDZ: Excavation Damaged Zone) zone, resulting from the initiation and growth of cracks and fractures and by a redistribution and rearrangement of the initial stresses. Due to …

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Research, Numerical Investigations and the Development of

The propagation of cracks, in the form of the DZ (excavation damage zone) is especially to be investigated depending on the depth and longwall heights, lengths and depth of propagation. Itasca's Role The objective was achieved through analyzing the available knowledge attained in the coal-mining industry, through rock mechanical modelling using

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11th congress of the International society for rock

Chunlin Li Statistical and neural regression approach for prediction of longwall chock-shield support pressure .. 1047 A.K. Verma & D. Deb Statistical joint modeling and stability analysis of rock blocks around a tunnel .. 1053 J.-W. Park, J.-J. Song & H.-J. Shim Study on tunnel excavation disturbed zone in weak rock with time-dependent

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An improved method for high‐efficiency coal mine methane

The damaged zone surrounded a borehole can be divided into a failure zone and a plastic zone. The failure zone was violently destroyed by the tangential stress concentration, and enormous fractures generated in the failure zone. These new fractures, combining with the primary fractures, created a densely meshed fracture system in the failure zone.

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Onsite Tests and Numerical Simulation of Broken Rock Zones

Dec 22, 2020 · Wang et al. investigated the excavation damaged zone around roadways during longwall mining in a coal mine and found that dynamic pressure and the roadway is in a wet state affected by the surface runoff. Due to the effect of blasting excavation, the surrounding rock of seepage roadway has more internal microcracks. extension progress

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Rock Engineering and Rock Mechanics: Structures in and on

Mar 01, 2015 · Quantitative assessment of an Excavation Damaged Zone from variations in seismic velocity and fracture distribution around a gallery in the Horonobe Underground Research Laboratory Impact of destress blasting on stress field development ahead of a hardcoal longwall face; Prediction of deformation modes of rock slope due to excavation on

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Extension of excavation damaged zone due to longwall

a function of two important factors: 1) characteristics of the excavation damaged zone (EDZ) above the gate roadway and 2) loading effect due to the caving zone (CZ) above the longwall working, which can extend the EDZ size. Generally, due to the coal seam dip, the failure possibility of main gate roadway is more severe than tail gate roadway.

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