scholarly journals Investigation on the Water Flow Evolution in a Filled Fracture under Seepage-Induced Erosion

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3188
Author(s):  
Jianli Shao ◽  
Qi Zhang ◽  
Xintao Wu ◽  
Yu Lei ◽  
Xunan Wu ◽  
...  
Keyword(s):  
Engineering Geology ◽  
Water Inrush ◽  
Stable Phase ◽  
Roughness Coefficient ◽  
Seepage Velocity ◽  
Linear Change ◽  
Flow Evolution ◽  
Seepage Characteristics ◽  
Seepage Properties ◽  
Safe Mining

Water inrush is a major geological hazard for safe mining and tunnel construction. For the water inrush channel containing mud, sand, and other sediments, it is difficult to predict the change of permeability and water surge, which makes disaster prevention difficult. As a typical water inrush channel, a filled fracture under seepage-induced erosion needs to be focused. In this work, a numerical model for the evolution of flow in a filled fracture under seepage-induced erosion was established, which included the seepage velocity, hydraulic erosion, and permeability of the filling medium. The effects of joint roughness coefficient (JRC) and homogeneity of the filling medium on the seepage evolution are discussed. The results showed that the fracture seepage properties experienced a non-linear change process, and the evolution can be divided into three phases: the slowly varying phase, the rapidly varying phase, and the stable phase. The increase of the JRC hindered the development in flow velocity and erosion. Compared with low homogeneous filling medium, pores in the high homogeneous filling medium were easier to expand and connect, and the seepage characteristics evolved faster. The model established in this study will help to understand the seepage evolution of filled fractures, and can be used to predict the permeability of filled fractures in engineering geology.

Influence of Joint Geometrical Characteristics on Seepage of Fractured Rock

2013 ◽  
Vol 631-632 ◽  
pp. 723-728
Author(s):  
Ke Man ◽  
Ju Wang ◽  
Rui Su ◽  
Yong Qiang Zhu
Keyword(s):  
Fractured Rock ◽  
Joint Surface ◽  
Roughness Coefficient ◽  
Geometrical Parameters ◽  
Joint Roughness Coefficient ◽  
Geometrical Characteristics ◽  
Aperture Width ◽  
Seepage Characteristics ◽  
Two Parameters ◽  
Seepage Properties

It describes the geometrical parameters of the joint surface in the fractured rock, through two parameters, i.e. JRC (Joint Roughness Coefficient) and JMC (Joint Matching Coefficient). Following these coefficients, the geometry of the surface has been measured exactly. Meanwhile, the rock deformation and seepage characteristics have been mainly defined by the joint surface, so the influence of JRC and JMC on the aperture width and the seepage properties have been deeply studied. Based on the cubic law of the flow water, the two parameters incorporated into the law and the permeability of the fractured rock has been obtained.

scholarly journals Evolution Model of Seepage Characteristics in the Process of Water Inrush in Faults

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Jianli Shao ◽  
Fei Zhou ◽  
Wenbin Sun
Keyword(s):  
Water Flow ◽  
Water Pressure ◽  
Water Inrush ◽  
Water Flow Rate ◽  
Initial Permeability ◽  
Effective Porosity ◽  
Evolution Model ◽  
Particle Migration ◽  
Evolution Process ◽  
Seepage Characteristics

Although the mechanism and influence of fault water inrush have been widely studied, there are still few studies on the migration of filling particles and the evolution process of seepage characteristics within faults. In this work, the coupling effects of water flow, particle migration, and permeability evolution are considered synthetically, and the evolution model of seepage characteristics with multifield coupling is established. This model was used to investigate the evolution process of water inrush within faults and the effects of water pressure, initial effective porosity, and initial permeability on water flow rate. The results show that the evolution of seepage characteristics can be divided into three phases: (i) low velocity seepage, (ii) drastic changes with substantial particle migration, and (iii) steady-state water flow. The multifield coupling causes the effective porosity, permeability, flow velocity, and particle concentration to accelerate each other during the dramatic phase. Moreover, the increases in initial water pressure, initial porosity, and initial permeability have different degrees of promotion on the water flow rate. Finally, the simulation results are approximately the same as the data of water inrush in the mining area, which verifies the correctness of the evolution model established in this work. This work provides new approaches to the evolution process and prevention of water inrush in faults.

Gravity Wave–Fine Structure Interactions. Part I: Influences of Fine Structure Form and Orientation on Flow Evolution and Instability

2013 ◽  
Vol 70 (12) ◽  
pp. 3710-3734 ◽  
Author(s):  
David C. Fritts ◽  
Ling Wang ◽  
Joseph A. Werne
Keyword(s):  
Fine Structure ◽  
Gravity Wave ◽  
Direct Numerical Simulations ◽  
Structure Alignment ◽  
Stable Phase ◽  
Structure Form ◽  
Wave Interactions ◽  
Initial Flow ◽  
Flow Evolution ◽  
Flow Components

Abstract Four idealized direct numerical simulations are performed to examine the dynamics arising from the superposition of a monochromatic gravity wave (GW) and sinusoidal linear and rotary fine structure in the velocity field. These simulations are motivated by the ubiquity of such multiscale superpositions throughout the atmosphere. Three simulations explore the effects of linear fine structure alignment along, orthogonal to, and at 45° to the plane of GW propagation. These reveal that fine structure alignment with the GW enables strong wave–wave interactions, strong deformations of the initial flow components, and rapid transitions to local instabilities and turbulence. Increasing departures of fine structure alignment from the GW yield increasingly less efficient wave–wave interactions and weaker or absent local instabilities. The simulation having rotary fine structure velocities yields wave–wave interactions that agree closely with the aligned linear fine structure case. Differences in the aligned GW fields are only seen following the onset of local instabilities, which are delayed by about 1–2 buoyancy periods for rotary fine structure compared to aligned, linear fine structure. In all cases, local instabilities and turbulence primarily accompany strong superposed shears or fluid “intrusions” within the rising, and least statically stable, phase of the GW. For rotary fine structure, local instabilities having preferred streamwise or spanwise orientations often arise independently, depending on the character of the larger-scale flow. Wave–wave interactions play the greatest role in reducing the initial GW amplitude whereas fine structure shears and intrusions are the major source of instability and turbulence energies.

scholarly journals Re-crushing process and non-Darcian seepage characteristics of broken coal medium in coal mine water inrush

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mingkun Pang ◽  
Tianjun Zhang ◽  
Yi Guo ◽  
Lei Zhang
Keyword(s):  
Flow Rate ◽  
Mine Water ◽  
Early Stage ◽  
Flow Behavior ◽  
Water Inrush ◽  
Sudden Change ◽  
Seepage Characteristics ◽  
Seepage Factor ◽  
Dependence Relationship ◽  
Infiltration Method

AbstractThe initiation process of the mine water inrush accident, the essence of this process is the sudden change of the seepage state of the broken coal medium under pressure and the instability of the skeleton. In order to study the re-crushing mechanism and seepage characteristics of the broken coal medium under load, a set of three-axis seepage system was designed independently. Using the steady-state infiltration method, multiple flow factors under different particle size combinations and different stress conditions of the broken coal medium were obtained. The results of the study indicate: in one hand, the reduction of the porosity of the broken coal medium will cause the flow channel to be rebuilt, and the sudden change of flow rate will directly lead to the non-Darcian flow behavior. The early stage of compaction mainly affects the permeability k value, and the later stage of compaction mainly affects the non-Darcian β value; On the other hand, the seepage throat in the broken coal medium may have a sharp increase in its flow rate, leading to a sudden change in the flow pattern. The critical Reynolds number is also used to determine whether non-Darcian flow is formed, and its value in the water inrush system is about 40–133; at the same time, the non-Darcian flow in the broken coal medium conforms to the Forchheimer-type flow law. By analyzing the dependence relationship between factors, a seepage factor representation algebraic relationship suitable for Forchheimer type non-Darcian flow of broken coal medium is given, which can be used as a calculation basis in the prevention and treatment of mine water inrush accidents.

scholarly journals A Coupled Nonlinear Flow Model for Particle Migration and Seepage Properties of Water Inrush through Broken Rock Mass

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Wenhao Shi ◽  
Tianhong Yang
Keyword(s):  
Rock Mass ◽  
Small Particle ◽  
High Velocity ◽  
Flow Behavior ◽  
Water Inrush ◽  
Particle Migration ◽  
Nonlinear Flow ◽  
Rock Mass Structure ◽  
Proposed Model ◽  
Seepage Properties

A large number of statistics indicate that broken rock mass always transforms into a flowing channel and leads to water inrush disasters in mining engineering, such as fault, karst, and strongly weathered rock mass. During the process of water inrush, the structure of the broken rock mass is constantly changing due to seepage erosion under high-velocity flow. Therefore, it is of vital importance to quantitatively evaluate the flow behavior of the water inrush related to the seepage erosion in order to prevent or reduce the risks. This study described a coupled nonlinear flow model, which couples the high-velocity seepage, the small particle migration, and the evolution of the broken rock mass structure. The model was verified firstly for simulation of nonlinear flow behavior by comparing with the traditional one. Then, the proposed model was used to simulate the evolution of particle migration and seepage properties of the water inrush through broken rock mass by a numerical case. The simulation results generally agree well with the existing experimental results. The simulations indicate that small particle migration causes the unstable characteristics of the seepage and the heterogeneity properties of the broken rock mass, which lead to the nonlinear flow behavior of the water inrush in both time and space. From a different perspective, it also indicates that the proposed model is capable of simulating the interaction of high-velocity seepage, small particle migration, and evolution of broken rock mass structure in the process of water inrush.

scholarly journals A Coupled Model of Two-Phase Fluid Flow and Heat Transfer to Transient Temperature Distribution and Seepage Characteristics for Water-Flooding Production Well with Multiple Pay Zones

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1854
Author(s):  
Guoshu Huang ◽  
Huolin Ma ◽  
Xiangyun Hu ◽  
Jianchao Cai ◽  
Jiabin Li ◽  
...  
Keyword(s):  
Water Saturation ◽  
Coupled Model ◽  
Water Flooding ◽  
Transient Temperature ◽  
Production Well ◽  
Seepage Velocity ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Seepage Characteristics ◽  
Phase Fluid

Temperature is one of the most prominent factors affecting production operations, predicting the accurate wellbore-formation temperature in a water-flooding production well is of great importance for multiple applications. In this paper, an improved coupled model of oil–water two-phase fluid flow and heat transfer was developed to investigate the transient temperature behavior for a producing well with multiple pay zones. Firstly, a novel method was derived to simulate the water saturation and the water breakthrough time (WBT) for tubing, which are key monitoring parameters in the process of water flooding. Then, we incorporated water saturation and an equation set for immiscible displacement to calculate the seepage velocity and the pressure of the two-phase fluid in the pay zones. Next, the upward seepage velocity of the tubing fluid change with depth was focused on, and the proper coupled initial and boundary conditions are presented at the interfaces, therewith the implicit finite difference method was used to compute the transient temperature with the input of the seepage characteristics for the reservoirs. Meanwhile, the validity of the proposed model has been verified by the typical model. Finally, a sensitivity analysis delineated that the production rate and the production time had a significant impact on the tubing fluid temperature. The overburden was hotter with a lower volumetric heat capacity or a higher thermal conductivity. In addition, the sensitivity of the porosity and the irreducible water saturation to formation temperature was significantly different before and after the WBT. The coupled model presented herein helps to advance the transient seepage characteristics analysis of pay zones, the precise temperature prediction is very useful for reservoir characterization and production analysis purposes and provides insight for designing the exploitation scheme in deep reservoirs and geothermal resources.

scholarly journals Numerical Simulation on the Seepage Properties of Soil-Rock Mixture

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ning Zhao ◽  
Yingchao Wang ◽  
Bo Meng ◽  
Ning Luo
Keyword(s):  
Dynamic Viscosity ◽  
Water Inrush ◽  
Water Velocity ◽  
Water Phase ◽  
Phase 2 ◽  
Initial Water ◽  
Fluent Software ◽  
Soil Skeleton ◽  
Seepage Properties ◽  
Properties Of Soil

To reveal the mechanism of water inrush in a fault tunnel and study the influence of different structures on the seepage process, a filling structure composed of a soil skeleton (fixed particles), a movable particles phase, and a water phase is constructed to simulate the rock mass broken by the fault. Fluent software is used to simulate the migration of the water phase in three different filling structures under different initial water velocities and dynamic viscosities. The variation law of the seepage time with the initial water velocity and dynamic viscosity in the three types of filling structures is obtained. The research shows the following: (1) the looser the filling structure, the greater the influence of gravity on the water phase seepage; the more compact the filling structure, the greater the spread range of the water phase and the more uniform the spread of the water phase. (2) The seepage time decreases with the increase in the initial water velocity. The seepage time and initial water velocity can be fitted by an exponential function. The effect of initial water velocity on seepage time is much greater than that of the structure. (3) The seepage time is related to both the dynamic viscosity and the structure. The seepage time increases with the increase in dynamic viscosity.

scholarly journals Seepage Property of Crushed Mudstone Rock in Collapse Column

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Bo-Yang Zhang ◽  
Zhi-Bin Lin
Keyword(s):  
Particle Size ◽  
Water Resource ◽  
Water Inrush ◽  
Underground Water ◽  
Economic Losses ◽  
Karst Collapse ◽  
Hydraulic Pressure ◽  
Water Flow Velocity ◽  
Collapse Column ◽  
Seepage Properties

The karst collapse column composed of crushed rocks and fine argillaceous or clay particles is easy to form the fissure channels between the coal seam working face and the confined limestone aquifer under mining and causes water inrush disasters with the loss of underground water resource, economic losses, and casualties. It is of great necessity to understand the seepage properties of crushed rock in karst collapse column for the prevention of water inrush and the protection of underground water resource. A self-developed seepage test system is used in this paper to conduct laboratory experiments on seepage properties of crushed mudstone specimens. The effects of the particle size distribution, the porosity (specimen height), and the hydraulic pressure on the water flow velocity and the permeability of crushed specimen are analyzed. The results indicate that the permeability of specimen increases with the particle size, porosity, and hydraulic pressure. It can be known from the comparative experiments of progressive hydraulic pressure on one specimen and variable hydraulic pressure on different specimens with constant particle size and porosity that more fine particles leak out from the specimen with repeated application of hydraulic pressure on one specimen. Therefore, the permeability of one specimen is bigger than that of different specimens under the condition of same hydraulic pressure.

Evaluation of Coal Floor Water Inrush Risk with Five-Figure and Double-Coefficient Method

2013 ◽  
Vol 706-708 ◽  
pp. 492-495
Author(s):  
Jiu Chuan Wei ◽  
Dao Lei Xie ◽  
Hui Yong Yin ◽  
Jian Bin Guo ◽  
Lin Lin Wang ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Water Inrush ◽  
Mining Area ◽  
Layer Depth ◽  
Effective Protection ◽  
Floor Water Inrush ◽  
Protection Layer ◽  
Inrush Water ◽  
Coefficient Method ◽  
Safe Mining

The coal seam floor water inrush risk assessment is the basis and foundation of inrush water disaster prevention[1-, this paper uses five figure double coefficient method evaluating NO.16 coalseam floor water inrush risk of Xin'an Coal Mine. Contour figure of the destroyed floor protection layer depth, the floor protection layer thickness, the head above seam floor, the effective protection layer thickness, and evaluation figure of mining above aquifer which can guide coal production were drawn to given the security zone within mining area and ensure safe mining.

scholarly journals Groundwater Inrush Control and Parameters Optimization of Curtain Grouting Reinforcement for the Jingzhai Tunnel

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Gan Li ◽  
Weibin Ma ◽  
Siming Tian ◽  
Zhou Hongbo ◽  
Fan Huabin ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Water Inrush ◽  
Parameters Optimization ◽  
Seepage Water ◽  
Curtain Grouting ◽  
Crack Zone ◽  
Water And Mud Inrush ◽  
Grouting Reinforcement ◽  
Seepage Characteristics ◽  
Seepage Channel

Based on the systematic study on the characteristics of water and mud inrush during the excavation of Jingzhai tunnel, the mechanism of water inrush seepage transformation caused by excavation disturbance is analyzed. By means of electromagnetic geophysical prospecting, the potential water bearing area of the tunnel was analyzed. The constitutive model of rock mass and grouting parameters are considered in the numerical simulation. The law of tunnel crack initiation and expansion under different curtain grouting parameters is proposed. The characteristics of seepage water inrush caused by excavation are described. It is considered that there are three stages in the seepage characteristics of tunnel: incubation, sudden, and stable. Numerical simulation was used to analyze the crack propagation track and water inflow characteristics under the grouting thickness of 3 m, 5 m, and 7 m. When the curtain grouting thickness was 3 m, the fracture field penetrated the curtain grouting area. The dominant seepage channel is formed, which greatly increases the probability of water inrush. When the curtain thickness is 5~7 m, the expansion of the crack zone can be controlled basically, so that the fracture and water bearing rock layer cannot form a seepage channel. At last, the grouting scheme of 6 m thick grouting and 20 m advanced grouting was selected, and the water seepage was reduced by 83%.

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