Forecasting Underground Water Dynamics within the Technogenic Environment of a Mine Field: Case Study

The objective is to analyze the dynamics of the underground water of a mine field based on the study of the geofiltration process of the rock mass disturbed by mining to achieve safe extraction operations as well as subsurface territories at the stage of the mining enterprise closure. Numerical modeling, based on a finite difference method under the conditions of multifactority and definite uncertainty of processes of transformation of technogenic environment of a mine field, helps solve a problem concerning underground water dynamics forecasting. A hydrodynamic model of the M.I. Stashkov mine was developed while solving option series of epignosis problems in terms of the chronology of mine field stoping. The abovementioned made it possible to identify regularities of the history of filtration, the capacity parameters of rock mass and the expansion of areas of heightened hydraulic conductivity as well as to evaluate qualitatively the water balance components of a carbonic watered formation and an overlying one. The stage of mining closure helped obtain the forecasting hydrodynamic solutions. The efficiency of measures, concerning reduction of water ingress into mine workings and the mitigation of surface ecological effects of mine flooding was evaluated quantitatively. It was determined that implementation of the water control procedures makes it possible to perform a 10–38% decrease in water ingress. In this context, they may be applied both independently and simultaneously. In terms of mine closure and flooding, a period of complete underground water recovery takes three years; in the process, surface zones of potential waterlogging and swamping are developed within the floodplain of Samara River, located at the territory of Western Donbas (Ukraine). The scientific novelty is to define regularities of hydraulic conductivity transformation of the rock mass of a mine field starting from the mine working roof fall, up to its compaction during the mine operation period. To do that, nonstationary identification problems were solved, using numerical modeling. The abovementioned makes it possible to improve the reliability of hydrodynamic prognoses and develop technological schemes to control water at the state of the mine closure.

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Numerical modeling of stress–strain state for host rock mass and thick gently dipping coal seam after mining completion in extraction panel

MINING INFORMATIONAL AND ANALYTICAL BULLETIN ◽

10.25018/0236-1493-2019-08-0-42-56 ◽

2019 ◽

Vol 8 ◽

pp. 42-56

Author(s):

V.A. Trofimov ◽

◽

S.S. Kubrin ◽

Yu.A. Filippov ◽

I.L. Kharitonov ◽

...

Keyword(s):

Numerical Modeling ◽

Rock Mass ◽

Coal Seam ◽

Host Rock ◽

Strain State ◽

Stress Strain ◽

Stress Strain State

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Rockslides on limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China

Natural Hazards and Earth System Science ◽

10.5194/nhess-14-2627-2014 ◽

2014 ◽

Vol 14 (9) ◽

pp. 2627-2635 ◽

Cited By ~ 7

Author(s):

Z. Feng ◽

B. Li ◽

Y. P. Yin ◽

K. He

Keyword(s):

Numerical Modeling ◽

Rock Mass ◽

Hard Rock ◽

Compression Fracture ◽

Field Observations ◽

Mountainous Areas ◽

Hard Rocks ◽

Rupture Plane ◽

Rock Collapse ◽

Cliff Retreat

Abstract. Calcareous mountainous areas are highly prone to geohazards, and rockslides play an important role in cliff retreat. This study presents three examples of failures of limestone cliffs with subhorizontal bedding in the southwestern calcareous area of China. Field observations and numerical modeling of Yudong Escarpment, Zengzi Cliff, and Wangxia Cliff showed that pre-existing vertical joints passing through thick limestone and the alternation of competent and incompetent layers are the most significant features for rockslides. A "hard-on-soft" cliff made of hard rocks superimposed on soft rocks is prone to rock slump, characterized by shearing through the underlying weak strata along a curved surface and backward tilting. When a slope contains weak interlayers rather than a soft basal, a rock collapse could occur from the compression fracture and tensile split of the rock mass near the interfaces. A rockslide might shear through a hard rock mass if no discontinuities are exposed in the cliff slope, and sliding may occur along a moderately inclined rupture plane. The "toe breakout" mechanism mainly depends on the strength characteristics of the rock mass.

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Hydro-Mechanical Coupled Analysis of the Stability of Surrounding Rock Mass of Underground Water-Sealed Oil Storage

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.405-408.402 ◽

2013 ◽

Vol 405-408 ◽

pp. 402-405 ◽

Cited By ~ 1

Author(s):

Yun Jie Zhang ◽

Tao Xu ◽

Qiang Xu ◽

Lin Bu

Keyword(s):

Rock Mass ◽

Underground Water ◽

Surrounding Rock ◽

Comsol Multiphysics ◽

Coupled Analysis ◽

Coupling Theory ◽

Oil Storage ◽

Stability Of Surrounding Rock ◽

Straight Wall ◽

The Stability

Based on the fluid-solid coupling theory, we study the stability of surrounding rock mass around underground oil storage in Huangdao, Shandong province, analyze the stress of the surrounding rock mass around three chambers and the displacement change of several key monitoring points after excavation and evaluate the stability of surrounding rock mass using COMSOL Multiphysics software. Research results show that the stress at both sides of the straight wall of cavern increases, especially obvious stress concentration forms at the corners of the cavern, and the surrounding rock mass moves towards the cavern after excavation. The stress and displacement of the surrounding rock mass will increase accordingly after setting the water curtains, but the change does not have a substantive impact on the stability of surrounding rock mass.

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Formulation of strain-dependent hydraulic conductivity for a fractured rock mass

International Journal of Rock Mechanics and Mining Sciences ◽

10.1016/j.ijrmms.2006.12.004 ◽

2007 ◽

Vol 44 (7) ◽

pp. 981-996 ◽

Cited By ~ 51

Author(s):

Yifeng Chen ◽

Chuangbing Zhou ◽

Yongqing Sheng

Keyword(s):

Rock Mass ◽

Hydraulic Conductivity ◽

Fractured Rock ◽

Fractured Rock Mass ◽

Strain Dependent

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An Estimation Model for Hydraulic Conductivity of Low-Permeability and Unfilled Fractured Granite in Underground Water-Sealed Storage Caverns

Geofluids ◽

10.1155/2021/6423048 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Yangbing Cao ◽

Weiguo Gong ◽

Xiangxiang Zhang ◽

Junxi Chen ◽

Zhenping Huang

Keyword(s):

Hydraulic Conductivity ◽

Water Pressure ◽

Underground Structure ◽

Underground Water ◽

Stress Index ◽

Low Permeability ◽

Proposed Model ◽

Imaging Results ◽

Water Conduction ◽

Fractured Granite

The permeability of rock mass is closely related to the stability and safety of underground structure, especially in underground water-sealed storage caverns. With regard to the estimation approaches in predicting the hydraulic conductivity of fractured granite in water-sealed storage caverns, there are some limitations of parameter selection leading to poor applicability. Focusing on the contribution of the water conduction fractures (WCF) to the hydraulic conductivity, we attempted to propose a novel model, the CA model, for estimating its hydraulic conductivity based on the fracture orientation index and the normal stress index by analyzing the borehole wall imaging results and borehole water-pressure test results in the site of underground water-sealed storage caverns. The results indicated that the proposed model is suitable for low-permeability and unfilled fractured granite, exhibiting good effectiveness by clarifying the relation between geomechanical parameters and hydraulic behavior. Further, the parameters upon which the proposed model is based are representative and easy to obtain, which has certain guiding significance and reference value for analyzing the permeability characteristics of similar rock masses.

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Optimizing Method of Main Caverns in Large Underground Water-Sealed Storage Caverns

10.21203/rs.3.rs-172577/v1 ◽

2021 ◽

Author(s):

Yang An ◽

E-chuan Yan ◽

Xing-ming Li ◽

Shao-ping Huang

Keyword(s):

Rock Mass ◽

Large Scale ◽

Distinct Element ◽

Strength Criterion ◽

Axial Direction ◽

Optimization Method ◽

Underground Water ◽

Land Resource ◽

Maximum Displacement ◽

Distinct Element Code

Abstract As a main method of petroleum strategic reserve in China, underground water-sealed storage cavern owns lots of outstanding advantages, such as low operating costs, high safety, and land resource conservation. Main caverns are important structure in underground project and the layout parameters and excavation scheme will have significant impact on overall project quality. The optimization method of main cavern layout and excavation scheme was put forward by a proposed large-scale underground water-sealed cavern project in China. First, based on field survey results, the Hoek-Brown strength criterion combined with rock mass quality Q classification system was used to estimate the equivalent mechanical parameters of rock mass. Second, the numerical experiments were carried out by relying on 3 Dimensions Distinct Element Code (3DEC). The discontinuous medium model was adopted, and displacements of key points, maximum displacement values and volume of the plastic zone were used as evaluation indicators. Axial direction, buried depth, spacing and excavation scheme of main caverns have been optimized. Results showed that axial direction should adopt NW325°, buried depth of cavern roof should locate at -100m, and distance between adjacent main caverns should be 1.5 times the span (36m). The “jump excavation” mode was recommended in construction. That is, the caverns on both sides should be excavated first, and the middle cavern should be excavated later. This mode could effectively reduce the interaction effect between caverns. This method has the characteristics of easy data acquisition and strong operability. It could be used to guide design and construction of similar projects . As a main method of petroleum strategic reserve in China, underground water-sealed storage cavern owns lots of outstanding advantages, such as low operating costs, high safety, and land resource conservation. Main caverns are important structure in underground project and the layout parameters and excavation scheme will have significant impact on overall project quality. The optimization method of main cavern layout and excavation scheme was put forward by a proposed large-scale underground water-sealed cavern project in China. First, based on field survey results, the Hoek-Brown strength criterion combined with rock mass quality Q classification system was used to estimate the equivalent mechanical parameters of rock mass. Second, the numerical experiments were carried out by relying on 3 Dimensions Distinct Element Code (3DEC). The discontinuous medium model was adopted, and displacements of key points, maximum displacement values and volume of the plastic zone were used as evaluation indicators. Axial direction, buried depth, spacing and excavation scheme of main caverns have been optimized. Results showed that axial direction should adopt NW325°, buried depth of cavern roof should locate at -100m, and distance between adjacent main caverns should be 1.5 times the span (36m). The “jump excavation” mode was recommended in construction. That is, the caverns on both sides should be excavated first, and the middle cavern should be excavated later. This mode could effectively reduce the interaction effect between caverns. This method has the characteristics of easy data acquisition and strong operability. It could be used to guide design and construction of similar projects .

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