scholarly journals Application of roof bolting to reduce water inflow into mine workings during the crossing of tectonic faults

2021 ◽  
Vol 280 ◽  
pp. 01006
Author(s):  
Oleksandr Krukovskyi ◽  
Viktoriia Krukovska ◽  
Yurii Vynohradov ◽  
Vladimir Dyomin
Keyword(s):  
Stress State ◽  
Mine Working ◽  
Numerical Study ◽  
Water Pressure ◽  
Stable State ◽  
Calculated Data ◽  
Water Inflow ◽  
Roof Bolting ◽  
Tectonic Disturbance ◽  
Hydrogeological Conditions

In this work, the problem of water inflow reduction in Ukrainian coal mines, which are distinguished by difficult hydrogeological conditions, was considered. A numerical study of the change in water inflow into a mine working when it crosses a tectonic fault was carried out. The cases when the permanent working was supported by frame supports and roof bolts were considered. The calculation of stress fields, zones with inelastic deformations and coefficients of permeability, which depend on the stress state and takes into account tectonic and natural permeability of the rocks, was performed. The results of calculating the water pressure and water inflow into the mine working in all considered cases are presented in the article. Analysis of the calculated data showed that a disturbed area, which covered water-bearing ricks, was formed in the roof of the mine working with the frame support. Within this area, water can move towards the contour of the mine working. The filtration permeability of the host rocks increases significantly when the mine face approaches the tectonic disturbance. The flow rate of water reaches critical values. The use of roof bolting restrains the unloading of the boundary rocks from the rock pressure and keeps them in a triaxially compressed stress state. The permeability value decreases by the value of its technological component. In different areas of the intersection of tectonic disturbance, the water inflow into the mine working with roof bolting is 3-8 times less than in the working, supported by frame supports. Therefore, the use of roof bolting allows not only to keep the mine working in a stable state, but also to significantly reduce water inflows at complicated hydrogeological conditions.

scholarly journals Water stability influence of host rocks on the process of water filtration into mine working with frame and roof-bolting support

2019 ◽  
Vol 109 ◽  
pp. 00041 ◽  
Author(s):  
Viktoriia Krukovska ◽  
Yurii Vynohradov
Keyword(s):  
Mine Working ◽  
Water Pressure ◽  
Water Inflow ◽  
Water Filtration ◽  
Water Stability ◽  
The Finite Element Method ◽  
Mining Operations ◽  
Roof Bolting ◽  
Host Rocks ◽  
Roof Rocks

The water stability influence of host rocks on water filtration process from the undermined aquifer to the mine working, depending on the way of its fastening has been studied in the paper. When solving the problem of water filtration in a deformable massif, the finite element method was used. The results of calculations are presented of the filtration permeability of the coal-bearing massif, the water pressure and the value of the water inflow into mine working in the cases of mining operations in sandstone and argillite. It is shown that the use of roof-bolting support prevents the development of the fractures formation process in the mine working roof, preserving the rocks in a natural, monolithic state. As a result, the process of water filtration from water bearing rock layers is constrained, which prevents or significantly reduces the soaking of border roof rocks. The use of roof-bolting fastening several times reduces the water inflow into mine working, located even in water-permeable rocks. The application of the roof-bolting support as a technological method for reducing the water inflow into mine workings has been substantiated.

scholarly journals Modification of the roof bolt support technology in the conditions of increasing coal mining intensity

2019 ◽  
Vol 109 ◽  
pp. 00042 ◽  
Author(s):  
Oleksandr Krukovskyi ◽  
Yurii Bulich ◽  
Yuliia Zemlianaia
Keyword(s):  
Coal Mining ◽  
Mine Working ◽  
Stable State ◽  
Roof Bolt ◽  
Suggested Approach ◽  
Roof Bolting ◽  
Working Face ◽  
The Face ◽  
Mine Workings ◽  
Host Rocks

The modification of the technology roof bolt supporting of mine workings in the conditions of increasing the coal mining intensity has been made. The technological schemes have been developed for the phased construction of roof bolting and frame support. This schemes make it possible to temporarily postpone the setting of frames in the mine working face, reduce the time and labour intensity for covering with a grid of the mine working arch and setting the bolts, as well as to increase the safety. The analysis of changes in the stress state of the border massif during the phased construction of roof bolting and frame support has been made. It is shown that the technology of phased construction of roof bolting and frame support ensures the maintaining a stable state of host rocks. In addition, the time between the extraction of the coal-rock mass and the setting of the primary support, as well as the distance between the face and the first row of roof bolts has been reduced to a minimum. The suggested approach makes possible to ensure the rate of preparatory mine workings development that are necessary for the intensification coal mining.

Engineering aspects of the mine working development in difficult hydrogeological conditions

2019 ◽  
pp. 132-141
Author(s):  
V.G. Hrinov ◽  
◽  
A.A. Khorolskyi ◽  
Yu.O. Vynohradov ◽  
◽  
...  
Keyword(s):  
Mine Working ◽  
Hydrogeological Conditions

scholarly journals Analysis of Tunnel Water Inrush Considering the Influence of Surrounding Rock Permeability Coefficient by Excavation Disturbance and Ground Stress

2021 ◽  
Vol 11 (8) ◽  
pp. 3645
Author(s):  
Helin Fu ◽  
Pengtao An ◽  
Long Chen ◽  
Guowen Cheng ◽  
Jie Li ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Water Inflow ◽  
Calculation Error ◽  
External Water Pressure ◽  
Ground Stress ◽  
External Water ◽  
Inflow Prediction

Affected by the coupling of excavation disturbance and ground stress, the heterogeneity of surrounding rock is very common. Presently, treating the permeability coefficient as a fixed value will reduce the prediction accuracy of the water inflow and the external water pressure of the structure, leading to distortion of the prediction results. Aiming at this problem, this paper calculates and analyzes tunnel water inflow when considering the heterogeneity of permeability coefficient of surrounding rock using a theoretical analysis method, and compares with field data, and verifies the rationality of the formula. The research shows that, when the influence of excavation disturbance and ground stress on the permeability coefficient of surrounding rock is ignored, the calculated value of the external water force of the tunnel structure is too small, and the durability and stability of the tunnel are reduced, which is detrimental to the safety of the structure. Considering the heterogeneity of surrounding rock, the calculation error of water inflow can be reduced from 27.3% to 13.2%, which improves the accuracy of water inflow prediction to a certain extent.

scholarly journals Analysis of Seepage Characteristics of a Foundation Pit with Horizontal Waterproof Curtain in Highly Permeable Strata

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1303
Author(s):  
Chenghua Shi ◽  
Xiaohe Sun ◽  
Shengli Liu ◽  
Chengyong Cao ◽  
Linghui Liu ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Theoretical Calculation ◽  
Calculation Method ◽  
Design Method ◽  
Water Pressure ◽  
Water Inflow ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Seepage Characteristics

At present, jet-grouted horizontal waterproof curtain reinforcement has become an essential method for deep foundation pit groundwater control. However, there is still a lack of an effective theoretical calculation method for horizontal waterproof curtain reinforcement, and there is little research on the seepage laws of foundation pits under different horizontal waterproof curtain conditions. Based on Darcy’s seepage theory, theoretical analysis models of deep foundation pit seepage were established considering the effect of a horizontal curtain in a highly permeable formation. Through the established models, the calculation method of the water inflow and the water pressure under the condition of a horizontal curtain was derived. Then through indoor tests, the reliability of the theoretical calculation method was verified. Furthermore, the established theoretical calculation method is used to analyze the influence of various factors on the water inflow and the water pressure, such as the ratio of hydraulic conductivity of the horizontal curtain to surrounding soil, thickness, and reinforcement position of the horizontal curtain. It is found that the hydraulic conductivity ratio has the most significant influence on the seepage characteristics of the foundation pit. Finally, the design method was applied to an example of the horizontal waterproof curtain of the foundation pit, which is located at Juyuanzhou Station in Fuzhou (China). The water inflow per unit area is 0.36 m3/d in the foundation pit, and this implies that the design method of the horizontal waterproof curtain applied for the excavation case is good and meets the requirements of design and safety.

Plugging Performance Optimization Tests of Grouting Material for Sudden Water Inflow of Underground Engineering Construction

2011 ◽  
Vol 306-307 ◽  
pp. 722-726 ◽  
Author(s):  
Li Ping Li ◽  
Shu Cai Li ◽  
Jin Sheng Cui ◽  
Zhao Li
Keyword(s):  
Performance Optimization ◽  
Water Pressure ◽  
High Water ◽  
Water Inflow ◽  
Karst Area ◽  
Seepage Water ◽  
Underground Engineering ◽  
Grouting Material ◽  
New Type ◽  
Plugging Performance

Sudden water inflow is the typical geological hazard during the construction period of underground, especially for the karst area. According to a new type of polymer chemical grout material called Malisan, plugging performance optimization tests of different grouting material had been carried out, such as ordinary cement, superfine cement and special cement of HSC, the geo time, consolidating strength, anti-erosion property and comprehensive properties of grouting harnessing had been systematically analyzed and compared. Test results showed that the new type of polymer chemical grout material has the significant characteristics of controllable gel time, high consolidating strength, anti-scour performance, water swelling and extremely strong permeability, it is more effective than conventional grouting material for grouting harnessing of seepage, water spraying and water inflow with high water pressure, in addition, it is convenient for transportation, material configuration and process operation.

scholarly journals Role of discrete water recharge from supraglacial drainage systems in modeling patterns of subglacial conduits in Svalbard glaciers

2019 ◽  
Vol 13 (3) ◽  
pp. 735-752 ◽  
Author(s):  
Léo Decaux ◽  
Mariusz Grabiec ◽  
Dariusz Ignatiuk ◽  
Jacek Jania
Keyword(s):  
Current Knowledge ◽  
Water Pressure ◽  
Drainage System ◽  
Stable State ◽  
Watershed Modeling ◽  
Potential Gradient ◽  
Water Runoff ◽  
Total Runoff ◽  
Water Recharge ◽  
Elevation Model

Abstract. As the behavior of subglacial water plays a determining role in glacier dynamics, it requires particular attention, especially in the context of climate warming, which is increasing ablation and generating greater amounts of meltwater. On many glaciers, water flowing from the glacier's surface is the main source of supply to the subglacial drainage system. This system is largely influenced by the supraglacial drainage system, which collects meltwater and precipitation and rapidly delivers it to discrete points in the glacier bed via moulins and crevassed areas, called water input areas (WIAs). Models of patterns of subglacial conduits mainly based on the hydrological potential gradient are still regularly performed without taking into account the supraglacial drainage system. We modeled the pattern of subglacial channels in two glaciers located in Svalbard, the land-terminating Werenskioldbreen and the tidewater Hansbreen during the 2015 melt season. We modeled a spatial and a discrete water recharge in order to compare them. First, supraglacial catchments were determined for each WIA on a high-resolution digital elevation model using the standard watershed modeling tool in ArcGIS. Then, interpolated water runoff was calculated for all the main WIAs. Our model also accounts for several water pressure conditions. For our two studied glaciers, during the ablation season 2015, 72.5 % of total runoff was provided by meltwater and 27.5 % by precipitation. Changes in supraglacial drainage on a decadal timescale are observed in contrast to its nearly stable state on an annual timescale. Nevertheless, due to the specific nature of those changes, it seems to have a low impact on the subglacial system. Therefore, our models of subglacial channel are assumed to be valid for a minimum period of two decades and depend on changes in the supraglacial drainage system. Results showed that, for Svalbard tidewater glaciers with large crevassed areas, models of subglacial channels that assume spatial water recharge may be somewhat imprecise but are far from being completely incorrect, especially for the ablation zone. On the other hand, it is important to take discrete water recharge into account in the case of land-terminating Svalbard glaciers with limited crevassed areas. In all cases, considering a discrete water recharge when modeling patterns of theoretical subglacial channels seems to produce more realistic results according to current knowledge.

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