scholarly journals Optimization of group borehole drainage of a mine above a high pressure, low permeability aquifer

2020 ◽  
Vol 15 (3) ◽  
pp. 660-672
Author(s):  
Haifeng Lu ◽  
Yuan Zhang ◽  
Manman Zhang ◽  
Guifang Zhang
Keyword(s):  
High Pressure ◽  
Water Pressure ◽  
Control Point ◽  
Mining Area ◽  
Low Permeability ◽  
Level Control ◽  
Effective Measure ◽  
Water Abundance ◽  
Variable Water ◽  
Good Drainage

Abstract Drainage to lower water pressure is an effective measure for preventing and controlling water ingress when mining above a confined aquifer. The deep limestone aquifer in the Huaibei mining area, China, generally has high pressure, low permeability and variable water abundance, so it is difficult to meet single-borehole drainage requirements. In order to achieve good drainage, and take into account engineering and environmental protection requirements, a multi-objective optimization model of group borehole drainage was established. The model takes the minimization of single-hole flow and borehole numbers as the objective functions, and the drawdown in drainage boreholes and the water level control point as the constraint conditions. The particle swarm optimization algorithm was used to solve the model. The results indicate that, for a low permeability aquifer, measures such as using partially penetrating wells, increasing the number of drainage boreholes appropriately and reducing individual borehole yield have good drainage effects. The extent of drilling and amount of drainage are also relatively small. This is all to the good for the drainage. When the optimization results were applied to coal-face drainage in Huaibei the outcome was good.

scholarly journals Optimization technology for group hole drainage of coal mining above deep high pressure and low permeability limestone aquifer

2020 ◽  
Author(s):  
Haifeng Lu ◽  
Yuan Zhang ◽  
Manman Zhang ◽  
Guifang zhang
Keyword(s):  
High Pressure ◽  
Coal Mining ◽  
Flow Rate ◽  
Permeability Coefficient ◽  
Water Pressure ◽  
Water Storage ◽  
Low Permeability ◽  
Limestone Aquifer ◽  
Single Hole ◽  
Drainage Effect

Abstract Drainage for decreasing water pressure is one of the effective measures to prevent and control water disaster caused of coal mining above high pressure limestone aquifer. The deep limestone aquifer in Huaibei mining area generally has the characteristics of high water pressure, low permeability and uneven water abundance so it is generally difficult to meet the requirements for single-hole drainage. In order to achieve the best drainage effect and consider the requirements of engineering quantity and environmental protection, a multi-objective group hole drainage optimization model was established, which takes the minimum of single-hole flow rate and hole number as the objective function and the requirements of drainage borehole and water level control point drawdown as the constraint conditions. And the particle swarm optimization algorithm was used to solve the model. On this basis, the influence of permeability coefficient and water storage coefficient on the calculation results was discussed. The results show that the permeability coefficient and water storage coefficient have great influence on the optimization of single-hole flow rate and the number of holes. For the low permeability aquifer, measures such as using partially penetrated well, appropriately increasing the number of drainage boreholes and reducing the single-hole flow rate have good drainage effect. And the drilling work amount and total drainage amount are relatively small. These are all good layout schemes for drainage. According to the results of optimization, the drainage of a coal face in Huaibei was guided and achieved good results.

scholarly journals Instruments and Methods High Pressure Coupling for Pipe in Deep Water Filled Bore Holes

1963 ◽  
Vol 4 (36) ◽  
pp. 809-812
Author(s):  
R. L. Shreve
Keyword(s):  
High Pressure ◽  
Water Pressure ◽  
The Other ◽  
Internal Diameter ◽  
External Diameter ◽  
Synthetic Rubber ◽  
External Water Pressure ◽  
External Water ◽  
One Year ◽  
Aluminum Pipe

AbstractIn August 1961 an aluminum pipe (3.5 cm. internal diameter, 4.2 cm. external diameter) having 92 specially modified socket couplings (5.0 cm. external diameter) sealed with a quick-polymerizing synthetic rubber was sunk 226 m. in a vertical water-filled bore hole in Blue Glacier, Washington. U.S.A. The geometry of threads and mating surfaces of pipe and coupling was designed to cause increasing external water pressure to tighten the seal. One joint at a depth of 66 m. immediately developed an extremely slow leak (probably because of faulty cleaning), but the other 91 joints apparently were sound, as the pipe was free of water to a depth of at least 157 m. when resurveyed after one year.

scholarly journals Automated technique for high-pressure water-based window cleaning and accompanying parametric study

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242413
Author(s):  
Youngjoo Lee ◽  
Daesung Kwon ◽  
Changmin Park ◽  
Myoungjae Seo ◽  
TaeWon Seo
Keyword(s):  
High Pressure ◽  
Evaluation Method ◽  
Water Pressure ◽  
Reaction Force ◽  
Field Tests ◽  
Image Data ◽  
Spray Angle ◽  
Cleaning Performance ◽  
Pressure Water ◽  
Automated Technique

The maintenance of buildings has become an important issue with the construction of many high-rise buildings in recent years. However, the cleaning of the outer walls of buildings is performed in highly hazardous environments over long periods, and many accidents occur each year. Various robots are being studied and developed to reduce these incidents and to relieve workers from hazardous tasks. Herein, we propose a method of spraying high-pressure water using a pump and nozzle, which differs from conventional methods. The cleaning performance parameters, such as water pressure, spray angle, and spray distance, were optimized using the Taguchi method. Cleaning experiments were performed on window specimens that were contaminated artificially. The cleaning performance of the proposed method was evaluated using the image-evaluation method. The optimum condition was determined based on the results of a sensitive analysis performed on the image data. In addition, the reaction force due to high pressure and impact force on the specimens were investigated. These forces were not sufficient to affect the propeller thrust or cause damage to the building’s surface. We expect to perform field tests in the near future based on the output of this research.

scholarly journals Analysis of the Effect of Different Combinations of Observation Satellites on the Resolving Accuracy of GNSS Observation Data

2020 ◽  
Vol 206 ◽  
pp. 03025
Author(s):  
Junze Wang ◽  
Maohua Yao ◽  
Wenting Zhou ◽  
Xiangping Chen
Keyword(s):  
Measurement Accuracy ◽  
Control Point ◽  
Satellite System ◽  
Base Stations ◽  
Observation Data ◽  
Control Points ◽  
Level Control ◽  
Satellite Systems ◽  
Beidou Navigation Satellite System ◽  
Stable Measurement

In this paper, 24 C-level control points under different terrain conditions were selected to be the testing points. The binary-satellite system (GPS+GLONASS) and the triple-satellite system with BeiDou Navigation Satellite System (BDS) (BDS+GPS+GLONASS) were adopted for static measurement; and the observation data from BeiDou Ground-based Augumentation System (GBAS) base stations in Guangxi were collected for solution. By comparing the residuals of GPS tri-dimensional baseline vectors and the internal accord accuracy of each control point under the binary and triple-satellite systems, the effect of data collected by different satellite systems under different terrain conditions on measurement accuracy was studied. According to the results, (1) the triple-satellite system with BDS showed more stable measurement accuracy; (2) in plane, the two systems were of equivalent measurement accuracy in mountainous and flat areas; in elevation, the triple-satellite system showed higher and more stable measurement accuracy.

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

Geofluids ◽  
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.

scholarly journals Analysis on Water Inrush Process of Tunnel with Large Buried Depth and High Water Pressure

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 134 ◽  
Author(s):  
Weimin Yang ◽  
Zhongdong Fang ◽  
Hao Wang ◽  
Liping Li ◽  
Shaoshuai Shi ◽  
...  
Keyword(s):  
High Pressure ◽  
Model Test ◽  
Water Pressure ◽  
Water Inrush ◽  
High Water ◽  
Surrounding Rock ◽  
Karst Cave ◽  
Tunnel Excavation ◽  
Pressure Water ◽  
High Water Pressure

In order to explore the catastrophic evolution process for karst cave water inrush in large buried depth and high water pressure tunnels, a model test system was developed, and a similar fluid–solid coupled material was found. A model of the catastrophic evolution of water inrush was developed based on the Xiema Tunnel, and the experimental section was simulated using the finite element method. By analyzing the interaction between groundwater and the surrounding rocks during tunnel excavation, the law of occurrence of water inrush disaster was summarized. The water inrush process of a karst cave containing high-pressure water was divided into three stages: the production of a water flowing fracture, the expansion of the water flowing fracture, and the connection of the water flowing fracture. The main cause of water inrush in karst caves is the penetration and weakening of high-pressure water on the surrounding rock. This effect is becoming more and more obvious as tunnel excavation progresses. The numerical simulation results showed that the outburst prevention thickness of the surrounding rock is 4.5 m, and that of the model test result is 5 m. Thus, the results of the two methods are relatively close to each other. This work is important for studying the impact of groundwater on underground engineering, and it is of great significance to avoid water inrush in tunnels.

scholarly journals Fatigue Damage at the Root of the Gate Lip of the Water Gate under Variable Water Pressure due to Tide and Ocean Wave

2004 ◽  
Vol 2004 (196) ◽  
pp. 169-179
Author(s):  
Keitaro Konuma ◽  
Masahiro Toyosada ◽  
Koji Gotoh ◽  
Koji Kawai ◽  
Noboru Igarashi
Keyword(s):  
Fatigue Damage ◽  
Water Pressure ◽  
Ocean Wave ◽  
Water Gate ◽  
Variable Water

scholarly journals Improved Method for Measuring the Permeability of Nanoporous Material and Its Application to Shale Matrix with Ultra-Low Permeability

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1567 ◽  
Author(s):  
Taojie Lu ◽  
Ruina Xu ◽  
Bo Zhou ◽  
Yichuan Wang ◽  
Fuzhen Zhang ◽  
...  
Keyword(s):  
High Pressure ◽  
Fluid Transport ◽  
Effective Means ◽  
Clean Energy ◽  
Nanoporous Materials ◽  
Environmental Research ◽  
Low Permeability ◽  
Matrix Permeability ◽  
Wide Range ◽  
The Matrix

Nanoporous materials have a wide range of applications in clean energy and environmental research. The permeability of nanoporous materials is low, which affects the fluid transport behavior inside the nanopores and thus also affects the performance of technologies based on such materials. For example, during the development of shale gas resources, the permeability of the shale matrix is normally lower than 10−3 mD and has an important influence on rock parameters. It is challenging to measure small pressure changes accurately under high pressure. Although the pressure decay method provides an effective means for the measurement of low permeability, most apparatuses and experiments have difficulty measuring permeability in high pressure conditions over 1.38 MPa. Here, we propose an improved experimental method for the measurement of low permeability. To overcome the challenge of measuring small changes in pressure at high pressure, a pressure difference sensor is used. By improving the constant temperature accuracy and reducing the helium leakage rate, we measure shale matrix permeabilities ranging from 0.05 to 2 nD at pore pressures of up to 8 MPa, with good repeatability and sample mass irrelevance. The results show that porosity, pore pressure, and moisture conditions influence the matrix permeability. The permeability of moist shale is lower than that of dry shale, since water blocks some of the nanopores.

scholarly journals Applicability Analysis of Klinkenberg Slip Theory in the Measurement of Tight Core Permeability

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2351 ◽  
Author(s):  
Jirui Zou ◽  
Xiangan Yue ◽  
Weiqing An ◽  
Jun Gu ◽  
Liqi Wang
Keyword(s):  
High Pressure ◽  
Gas Permeability ◽  
Fluid Dynamic ◽  
Dynamic Parameter ◽  
Low Pressure ◽  
Low Permeability ◽  
Apparent Permeability ◽  
Tight Reservoir ◽  
Gas Seepage ◽  
The Relationship

The Klinkenberg slippage theory has widely been used to obtain gas permeability in low-permeability porous media. However, recent research shows that there is a deviation from the Klinkenberg slippage theory for tight reservoir cores under low-pressure conditions. In this research, a new experimental device was designed to carry out the steady-state gas permeability test with high pressure and low flowrate. The results show that, unlike regular low-permeability cores, the permeability of tight cores is not a constant value, but a variate related to a fluid-dynamic parameter (flowrate). Under high-pressure conditions, the relationship between flowrate and apparent permeability of cores with low permeability is consistent with Klinkenberg slippage theory, while the relationship between flowrate and apparent permeability of tight cores is contrary to Klinkenberg slip theory. The apparent permeability of tight core increases with increasing flowrate under high-pressure conditions, and it is significantly lower than the Klinkenberg permeability predicted by Klinkenberg slippage theory. The difference gets larger when the flowrate becomes lower (back pressure increases and pressure difference decreases). Therefore, the Klinkenberg permeability which is obtained by the Klinkenberg slippage theory by using low-pressure experimental data will cause significant overestimation of the actual gas seepage capacity in the tight reservoir. In order to evaluate the gas seepage capacity in a tight reservoir precisely, it is necessary to test the permeability of the tight cores directly at high pressure and low flowrate.

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