Underground Hazards Research Articles

GCNet: Ground Collapse Prediction Based on the Ground-Penetrating Radar and Deep Learning Technique

Manual methods to detect and identify potential ground collapse hazards have a high volume of workload and rely on manual skills and experience strongly, with substantial inconsistencies. This paper proposes an automatic recognition method of potential underground hazards and designs an object detection-based algorithm to predict the hidden danger of ground collapse, called GCNet. The GCNet is a ground collapse hazard detection network, which is developed to detect underground hazards, including cavities, poor soil quality, pipelines, and soil background. The GCNet uses the deep residual network ResNet101 and feature pyramid network (FPN) to extract features and a task coordination network (TCN) to identify the category and location of hidden underground hazards. Further, a feature enhancement method based on the regional binary pattern is proposed to improve the accuracy of the proposed model by expanding the ground-penetrating radar (GPR) data by adding multi-level features to GPR images. The experiments are conducted on a large amount of real GPR data and experiment results show that the proposed automatic recognition method can surpass the existing deep learning-based methods in hidden underground hazard recognition and identification.

Soil Erosion Due to Defective Pipes: A Hidden Hazard Beneath Our Feet

Sinkholes are a significant underground hazard that threatens infrastructure and lives and sometimes results in fatalities. The annual cost of sinkhole damages exceeds $300 million, although this estimate is likely underestimated due to the need for national tracking. Sinkholes can also alter natural drainage patterns, leading to increased flood risk. While natural sinkholes occur, those in urban areas are predominantly manmade, caused by soil erosion from defective pipes, typically due to aging. Climate change, storm surges, and urbanization have accelerated subsidence in urban environments, posing greater risks to critical infrastructure and densely populated areas. Extensive research has focused on soil erosion in dams; however, this knowledge does not necessarily apply to erosion through orifices, where gravity and other factors play significant roles. This paper presents a critical literature review on internal soil erosion due to defective pipes (SEDP). The review highlights that hydraulic loading, backfill type, and pipe conditions (defect shape, size, and depth) influence SEDP. Key findings from experiments and numerical studies are summarized, while mechanisms and knowledge gaps are identified. However, it is concluded that the current understanding in this field remains limited, underscoring the urgent need for further experimental and numerical research to expand the knowledge base on SEDP.

IoT(Internet of Things)-based Underground Risk Assessment System Surrounding Water Pipes in Korea

IoT (Internet of Things) based underground risk assessment system surrounding water pipes enables an advanced monitoring and prediction for unexpected underground hazards such as abrupt road-side subsidence and urban sinkholes due to a leak in water pipes. For the development of successful assessment technology, the PSU (Pipe Safety Unit) is under development which detects the leakage and movement of water pipes. Then, the IoT-based underground risk assessment system surrounding water pipes will be proposed. The system consists of early detection tools for underground events and correspondence services, by analyzing leakage and movement data collected from PSU. These methods must be continuous and reliable, and cover certain block area ranging a few kilometers, for properly applying to regional water supply changes.

상수도관로의 주변 지반침하 위험도 평가를 위한 안전감시 센서

IoT(Internet of Things) based underground risk assessment system surrounding water pipeline enables an advanced monitoring and prediction for unexpected underground hazards such as abrupt road-side subsidence and urban sinkholes due to a leak in water pipeline. For the development of successful assessment technology, the PSU(Water Pipeline Safety Unit) which detects the leakage and movement of water pipes. Then, the IoT-based underground risk assessment system surrounding water pipeline will be proposed. The system consists of early detection tools for underground events and correspondence services, by analyzing leakage and movement data collected from PSU. These methods must be continuous and reliable, and cover certain block area ranging a few kilometers, for properly applying to regional water supply changes.

Extreme Deepwater Wells Push Drillers to Begin Using Managed-Pressure Methods

Dual-Gradient Drilling Dual-gradient drilling has long been described as the drilling method of the future for challenging offshore wells. Now there are indications that it could start being used with some regularity, with multiple-well campaigns possible as early as next year. This method of managed-pressure drilling has been used a handful of times on a floating drilling rig, mostly to precisely manage the pressure in wells while drilling in weak, low-pressure formations prone to major fluid losses. Currently, Chevron and Statoil are seeking to use the system for deep, difficult, high-pressure formations in the US Gulf of Mexico. A drillship leased by Chevron, Pacific Santa Ana, is testing dual-gradient equipment on the ocean bottom while drilling a conventional well, and the company has leased a second drillship from Pacific Drilling, Pacific Sharav, that was built to accommodate dual-gradient drilling equipment. Statoil is seeking a permit to drill what could be the first dual-gradient well in the deep waters of the Gulf of Mexico, using another version of the managed-pressure method. “When we came here to the Gulf of Mexico, it was a perfect match with the challenges we had here,” said Uno Holm Rognli, vice president of drilling and wells in the offshore US for Statoil. “We started a program locally to develop this system” for conditions in the Gulf. It is the next step for the method used by Statoil off Norway, and by three companies in water 7,500 ft deep off Cuba. In both places it was used to successfully drill wells where pressure was so low, and the rock so fragile, that wells drilled using conventional methods were plagued by major fluid losses. While a few pioneers are working on dual-gradient drilling, there is a broader, growing base of operators using managed-pressure systems offshore. These are closed-loop systems with metering to allow precise measurement of change in fluid flows and chokes that allow them to apply backpressure when needed. Petronas and Petrobras are embracing managed-pressure drilling to deal with offshore wells where total fluid loss makes some wells impossible to drill using conventional methods. Managed-pressure equipment allows them to drill through sections of wells with cavernous underground hazards that can cause major fluid loss by using managed-pressure methods such as mud-cap drilling. ’New Ways To Manage Pressure Raise Well Control Questions’ When discussing dual-gradient drilling, there is an important distinction between controlling wells and well control. Controlling wells requires maintaining the balance between preventing influxes that could lead to trouble and exceeding the limit that could push drilling fluids out of the well and into the formation. Well control refers to the hardware, procedures, and training associated with dealing with situations in which an influx has occurred and needs to be quickly stopped before it grows into a bigger problem, and then circulated out of the well. For companies seeking to win approval from the US Bureau of Safety and Environmental Enforcement (BSEE) to drill the first deepwater well in the US Gulf of Mexico using dual-gradient drilling, questions about well control are critical. Offshore regulators want to be sure that all the new equipment has been thoroughly tested because this is a new way to drill, and the BSEE wants to be sure that it is understood that when it comes to well control, the requirements are not changing. “With Dual-Gradient Drilling, the Name Requires Explanation” Dual-gradient drilling covers a variety of methods for managing pressure within an offshore well while drilling. Dual refers to systems built to reduce or eliminate the pressure added by drilling fluid in the riser. The goal is to create distinct pressure gradients above and below the mudline. It is a departure from the simpler traditional approach using a single fluid combining water or oil plus drilling mud to make it viscous enough to remove cuttings while drilling, and just heavy enough to control pressures in the open hole without causing damage. As drilling moved into deeper waters the gap has narrowed between the effective mud weight-per-gallon to offset the formation pressure, and the level that can fracture it. Drillers refer to this slim margin as working within tight drilling windows.

Modelling and Simulating of Risk Behaviours in Virtual Environments Based on Multi-Agent and Fuzzy Logic

Due to safety and ethical issues, traditional experimental approaches to modelling underground risk behaviours can be costly, dangerous and even impossible to realize. Based on multi-agent technology, a virtual coalmine platform for risk behaviour simulation is presented to model and simulate the human-machine-environment related risk factors in underground coalmines. To reveal mine workers' risk behaviours, a fuzzy emotional behaviour model is proposed to simulate underground miners' responding behaviours to potential hazardous events based on cognitive appraisal theories and fuzzy logic techniques. The proposed emotion model can generate more believable behaviours for virtual miners according to personalized emotion states, internal motivation needs and behaviour selection thresholds. Finally, typical accident cases of underground hazard spotting and locomotive transport were implemented. The behaviour believability of virtual miners was evaluated with a user assessment method. Experimental results show that the proposed models can create more realistic and reasonable behaviours in virtual coalmine environments, which can improve miners' risk awareness and further train miners' emergent decision-making ability when facing unexpected underground situations.

Casing mechanism of engineering hazards in a oil field in central China

Based on the statistics data extracted from underground hazards in “A” region of Yuan Shi oilfield, and with casing failures as an example, engineering hazards, such as sand production, casing hazards, etc., in different geological structures are compared and distinguished. A detailed examination of their relationship is conducted in terms of mineral composition, sedimentary facies and other reservoir aspects. The triggering mechanism of engineering hazards is also theorized. Especially under water injection, the effect of geological structures on engineering hazards is illustrated. Finally, engineering hazards prevention and minimization measures are presented. The results show that in fluvial sediments, casing damage is mainly on the outside of the casing and casing bending. In a shallow lake environment, casing damage is chiefly of the leakage and rupture type.

Characterization and Triggering Mechanism of Underground Engineering Hazards in a Terrestrial Oil Field in Central China

On the basis of the statistics data extracted from underground hazards in “A” region of Yuan Shi oilfield, and with casing failures as an example, engineering hazards such as sand production, casing damages etc. in different geological structures are compared and distinguished. A detailed examination of their relationship is conducted in terms of mineral composition, sedimentary facies and other reservoir aspects. The triggering mechanism of engineering hazards is also theorized. Especially, under water injection, the effect of geological structures on engineering hazards is illustrated. Finally, engineering hazards prevention and minimization measures are presented. The latter include: 1) the shallow underground water must be fine filtered with oxygen removed & sterilized, and water pipelines corroded in the entire process; 2) reduce the casing pipe intensity by injected water corrosion.

Basin evolution and coal geology of the Donets Basin (Ukraine, Russia): An overview

Abstract The Donets Basin is a major coal-mining district in eastern Ukraine and adjacent portions of Russia. It comprises the Donbas Foldbelt, which is the uplifted and compressionally deformed part of the Pripyat–Dniepr–Donets (PDD) Basin, and the significantly less deformed Western Donbas region. The PDD Basin is a Late Devonian rift structure located within the East European Craton. Thick coal-measures formed during the post-rift stage of the basin in Serpukhovian to Moscovian times, when about 130 seams, each with a thickness over 0.45 m, have been deposited. Early Serpukhovian coal accumulated in a relatively narrow shore-zone. It is rich in inertinite and liptinite and very low in ash. Bashkirian and Moscovian coal have a significantly wider lateral extension and are generally rich in vitrinite. Bashkirian and Moscovian coal seams usually have high ash yields (12–18%) and high sulfur contents (2.5–3.5%), but these data vary significantly depending on peat facies. Coal rank ranges from subbituminous to anthracite and is mainly controlled by the depth of the seams and the heat flow during maximum (Permian) burial. Permo-Triassic thermal events locally overprinted the resulting coalification pattern. Coked coal occurs at the contact to presumed Permian sills and dikes southwest of Donetsk. Deep Permian burial was followed by major Permian and Mesozoic uplift events. The Donets Basin hosts proven reserves in the order of 60 Gt at the exploitable depth. The thickness of coal seams currently mined is in the range of 0.6 to 2.5 m. Production during 2009 was 68.7 Mt in the Ukrainian and 4.9 Mt in the Russian part of the basin. Coal mines in the Donets Basin are among the gassiest in the world. The average methane content of coal is 14.7 m³/t, but numerous seams have significantly higher gas content. The high methane content presents a severe mine safety problem. On the other hand, it represents also a high potential for coal mine bed methane projects. Emissions of coal gas released by mining and related structurally induced underground hazards (coal and gas outbursts) are a major problem for safe and efficient coal exploitation in the basin.

JACKSON, I. (ed.) 2004. Britain Beneath Our Feet. An Atlas of Digital Information on Britain's Land Quality, Underground Hazards, Resources and Geology. vi+114 pp. Keyworth: British Geological Survey. Price £5.00 (paperback). ISBN 085272479 9

JACKSON, I. (ed.) 2004. Britain Beneath Our Feet. An Atlas of Digital Information on Britain's Land Quality, Underground Hazards, Resources and Geology. vi+114 pp. Keyworth: British Geological Survey. Price £5.00 (paperback). ISBN 085272479 9 - Volume 142 Issue 2

The two-phase model applied to some U.S. coals

The Donets Basin is a major coal-mining district in eastern Ukraine and adjacent portions of Russia. It comprises the Donbas Foldbelt, which is the uplifted and compressionally deformed part of the Pripyat–Dniepr–Donets (PDD) Basin, and the significantly less deformed Western Donbas region. The PDD Basin is a Late Devonian rift structure located within the East European Craton. Thick coal-measures formed during the post-rift stage of the basin in Serpukhovian to Moscovian times, when about 130 seams, each with a thickness over 0.45 m, have been deposited.Early Serpukhovian coal accumulated in a relatively narrow shore-zone. It is rich in inertinite and liptinite and very low in ash. Bashkirian and Moscovian coal have a significantly wider lateral extension and are generally rich in vitrinite. Bashkirian and Moscovian coal seams usually have high ash yields (12–18%) and high sulfur contents (2.5–3.5%), but these data vary significantly depending on peat facies.Coal rank ranges from subbituminous to anthracite and is mainly controlled by the depth of the seams and the heat flow during maximum (Permian) burial. Permo-Triassic thermal events locally overprinted the resulting coalification pattern. Coked coal occurs at the contact to presumed Permian sills and dikes southwest of Donetsk. Deep Permian burial was followed by major Permian and Mesozoic uplift events.The Donets Basin hosts proven reserves in the order of 60 Gt at the exploitable depth. The thickness of coal seams currently mined is in the range of 0.6 to 2.5 m. Production during 2009 was 68.7 Mt in the Ukrainian and 4.9 Mt in the Russian part of the basin. Coal mines in the Donets Basin are among the gassiest in the world. The average methane content of coal is 14.7 m³/t, but numerous seams have significantly higher gas content. The high methane content presents a severe mine safety problem. On the other hand, it represents also a high potential for coal mine bed methane projects. Emissions of coal gas released by mining and related structurally induced underground hazards (coal and gas outbursts) are a major problem for safe and efficient coal exploitation in the basin.

Some applications of seismic mechanism studies to assessing underground hazard : Proc 1st International Congress on Rockbursts and Seismicity in Mines, Johannesburg, Sept 1982 P199–208. Publ Johannesburg: SAIMM, 1984

Some applications of seismic mechanism studies to assessing underground hazard : Proc 1st International Congress on Rockbursts and Seismicity in Mines, Johannesburg, Sept 1982 P199–208. Publ Johannesburg: SAIMM, 1984