Predicting Fractured Zones in the Culebra Dolomite

2013 ◽  
pp. 103-115 ◽  
Author(s):  
Robert M. Holt ◽  
Richard L. Beauheim ◽  
Dennis W. Powers
Keyword(s):  
Fractured Zones

scholarly journals Electromagnetic profiling of Owena Dam, Southwestern Nigeria, using very-low-frequency radio fields

2016 ◽  
Vol 63 (4) ◽  
pp. 237-250 ◽  
Author(s):  
Cyril Okpoli ◽  
Raphael Tijani
Keyword(s):  
Low Frequency ◽  
Soil Mass ◽  
Internal Erosion ◽  
Dam Failure ◽  
Real Component ◽  
Southwestern Nigeria ◽  
Very Low Frequency ◽  
Embankment Dams ◽  
Fractured Zones ◽  
Basement Structures

AbstractVery low frequency (VLF) was used to assess variations in overburden composition, bedrock lithology and the concealed basement structures within the bedrock of Owena Dam in Igbara-Oke of the Precambrian Basement Complex of Southwestern Nigeria. Five VLF-electromagnetic (EM) traverses were occupied at 5 m intervals. The VLF normal and filtered real component anomalies identify major geological interfaces suspected to be faults/fractured zones. The points of crossover between the real and imaginary components delineate the fractured zones, which were identified as areas of possible seepage (piping and sloughing). The internal erosion (permeability) of soil mass eventually leads to the formation of an open conduit in the soil, which may lead to failure of the embankment/dam. The fractured zones are suspected to be present at all traverses. In total, 21 fractured zones were identified along the dam embankment, with the deepest occurrence at Traverse 5. These seepage zones cause heterogeneity in the subsurface composition, which could lead to dam failure. The result of the study suggests that VLF is an adequate method of monitoring seepages in embankment dams.

From outcrop to subsurface model—Large-scale fractured zones in Apulian platform carbonates (Maiella Mountains, Central Apennines, Italy)

AAPG Bulletin ◽  
2021 ◽  
Vol 105 (12) ◽  
pp. 2449-2476
Author(s):  
Stefano Torrieri ◽  
Chadia Volery ◽  
Loï Bazalgette ◽  
Christoph G. E. Strauss
Keyword(s):  
Large Scale ◽  
Central Apennines ◽  
Fractured Zones ◽  
Platform Carbonates

scholarly journals A Mechanical Model of the Overlying Rock Masses in Undersea Coal Mining and a Stress-Seepage Coupling Numerical Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Jie Fang ◽  
Lei Tian ◽  
Yanyan Cai ◽  
Zhiguo Cao ◽  
Jinhao Wen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Coal Mining ◽  
Water Inrush ◽  
Mining Area ◽  
Analysis Model ◽  
Fractured Zones ◽  
Working Face ◽  
Seam Mining ◽  
Overlying Strata

The water inrush of a working face is the main hidden danger to the safe mining of underwater coal seams. It is known that the development of water-flowing fractured zones in overlying strata is the basic path which causes water inrushes in working faces. In the engineering background of the underwater mining in the Longkou Mining Area, the analysis model and judgment method of crack propagation were created on the basis of the Mohr–Coulomb criterion. Fish language was used to couple the extension model into the FLAC3d software, in order to simulate the mining process of the underwater coal seam, as well as to analyze the initiation evolutionary characteristics and seepage laws of the fractured zones in the overlying strata during the advancing processes of the working face. The results showed that, during the coal seam mining process, the mining fractured zones which had been caused by the compression-shear and tension-shear were mainly concentrated in the overlying strata of the working face. Also, the open-off cut and mining working face were the key sections of the water inrush in the rock mass. The condition of the water disaster was the formation of a water inrush channel. The possible water inrush channels in underwater coal mining are mainly composed of water-flowing fractured zones which are formed during the excavation processes. The numerical simulation results were validated through the practical engineering of field observations on the height of water-flowing fractured zone, which displayed a favorable adaptability.

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