CN111859751A - Method for predicting water inflow of underground inclined hydrophobic borehole of coal mine - Google Patents
Method for predicting water inflow of underground inclined hydrophobic borehole of coal mine Download PDFInfo
- Publication number
- CN111859751A CN111859751A CN202010692059.7A CN202010692059A CN111859751A CN 111859751 A CN111859751 A CN 111859751A CN 202010692059 A CN202010692059 A CN 202010692059A CN 111859751 A CN111859751 A CN 111859751A
- Authority
- CN
- China
- Prior art keywords
- hydrophobic
- aquifer
- borehole
- water
- water inflow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 130
- 230000002209 hydrophobic effect Effects 0.000 title claims abstract description 123
- 238000000034 method Methods 0.000 title claims abstract description 68
- 239000003245 coal Substances 0.000 title claims abstract description 51
- 238000005553 drilling Methods 0.000 claims abstract description 23
- 239000003673 groundwater Substances 0.000 claims abstract description 18
- 238000004088 simulation Methods 0.000 claims abstract description 17
- 238000004364 calculation method Methods 0.000 claims abstract description 12
- 238000013178 mathematical model Methods 0.000 claims abstract description 12
- 239000002131 composite material Substances 0.000 claims abstract description 7
- 230000035699 permeability Effects 0.000 claims description 8
- 230000001133 acceleration Effects 0.000 claims description 7
- 230000010354 integration Effects 0.000 claims description 6
- 238000005094 computer simulation Methods 0.000 claims description 5
- 230000005484 gravity Effects 0.000 claims description 4
- 239000011148 porous material Substances 0.000 claims description 4
- 230000001052 transient effect Effects 0.000 claims description 4
- 230000004907 flux Effects 0.000 claims description 3
- 230000002093 peripheral effect Effects 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 239000012530 fluid Substances 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000009412 basement excavation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/28—Design optimisation, verification or simulation using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2111/00—Details relating to CAD techniques
- G06F2111/10—Numerical modelling
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2113/00—Details relating to the application field
- G06F2113/08—Fluids
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Engineering & Computer Science (AREA)
- Geometry (AREA)
- Evolutionary Computation (AREA)
- Fluid Mechanics (AREA)
- Pure & Applied Mathematics (AREA)
- Mathematical Physics (AREA)
- Mathematical Optimization (AREA)
- Mathematical Analysis (AREA)
- Computing Systems (AREA)
- Algebra (AREA)
- Geophysics And Detection Of Objects (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
A prediction method for water inflow of a coal mine underground oblique hydrophobic borehole comprises the following steps: the method comprises the following steps: determining a mathematical model of the movement of the groundwater of the aquifer to the upward inclined borehole; step two: determining a simulation range and a simulation boundary of the numerical model; step three: constructing and discretizing a composite numerical model of the hydrophobic aquifer and the upward-inclined drill hole; step four: the hole wall of the oblique drilling hole is generalized into a seepage overflow boundary, and the simulation is closer to a real seepage field based on a definition method of a definite solution condition of a seepage overflow condition; step five: inputting a hydrophobic aquifer in a numerical model according to the field measured data; step six: integrating Darcy flow velocity of the wall of the hydrophobic borehole in real time, and dynamically calculating the dynamic water inflow of the oblique hydrophobic borehole; therefore, the method is based on the unsteady seepage motion model of the underground water, adopts a finite element model method to dynamically predict the numerical value of the water inflow process of the coal mine upward inclined hydrophobic borehole, and realizes the dynamic calculation of the water inflow amount of the coal mine downward upward inclined hydrophobic borehole.
Description
Technical Field
The invention relates to the technical field of mine water prevention and control and underground water resource protection, in particular to a method for predicting water inflow of an underground inclined hydrophobic borehole of a coal mine.
Background
Before the coal face of the underground coal mine is stoped, the aim is to construct drainage drill holes in a centralized manner towards a water-bearing stratum of a roof underground, and the underground water in the water-bearing stratum is drained (dried) in advance, so that the roof water burst strength is reduced in the coal mine excavation process, and the main means for treating the water hazard of the roof is provided. As shown in fig. 1A and fig. 1B, a coal mine underground drainage borehole generally passes through a coal seam from a roadway opening upwards and obliquely enters a roof aquifer (referred to as an oblique borehole for short), the water inflow of the oblique drainage borehole has an obvious attenuation rule, the water inflow of the borehole in the early stage of drainage generally consists of aquifer static reserve Qs and dynamic supply quantity Qd, the underground water flow field reaches a dynamic balance state as the water level depth and the water attenuation rate are smaller and smaller along with the extension of a drainage period, and the water amount in the stage is mainly dynamically supplied to the aquifer. Therefore, the difference between the spatial structure and the water burst form of the inclined hydrophobic drill hole and the water pumping of the ground vertical well is obvious, the water discharging process of the underground inclined hydrophobic drill hole is generalized to the water pumping process of the ground vertical well, and the fur clothing predicts the water burst process of the underground hydrophobic drill hole to have larger errors according to the stable flow theory. Although the empirical formula of the single-hole water inflow of the underground exploration and drainage old air water body drill hole is given in the manual of the general engineers in coal mines, the empirical formula is derived based on Bernoulli equation in hydrodynamics, and is formed by derivation under the condition that the water level is unchanged and the flow of an orifice is constant, so that the method is suitable for estimating the water inflow of the exploration and drainage drill hole under the condition that a water filling water source is surface water and old air water, and is obviously not suitable for estimating the water inflow of the underground exploration and drainage old air water in the form of aquifer seepage.
Therefore, how to scientifically predict the change process of the water inflow of the underground inclined hydrophobic borehole of the coal mine is a technical problem which is difficult to solve for a long time in the field.
Therefore, in view of the defects, through careful research and design, the designer of the invention researches and designs a method for estimating the water inflow of the underground inclined hydrophobic borehole of the coal mine by combining the experience and the result of the related industry for years, so as to overcome the defects.
Disclosure of Invention
The invention aims to provide a method for predicting the water inflow of an inclined hydrophobic borehole in a coal mine, which can overcome the defects of the prior art. Discretizing a computer model compositely depicting a hydrophobic aquifer and a drilled hole on the coal face scale by using a finite element triangular tetrahedron unit subdivision method; the peripheral boundary of the hydrophobic aquifer is numerically depicted by utilizing an infinite definition method; the wall of the hydrophobic drill hole is numerically depicted by adopting a Darcy seepage overflow boundary definition method; and realizing dynamic calculation of the water inflow of the underground inclined hydrophobic borehole of the coal mine by integrating the Darcy flow velocity u of the wall of the hydrophobic borehole in real time.
In order to achieve the purpose, the invention discloses a method for predicting water inflow of an underground oblique hydrophobic borehole of a coal mine, which is characterized by comprising the following steps of:
the method comprises the following steps: the selection of a mathematical model of the movement of the groundwater of the aquifer to the borehole is described by adopting a Darcy unsteady seepage mathematical model, such as the following formula (1) and formula (2):
in the formula:pis the porosity of the water-containing layer; rho is the density of water, kg/m3；
Is Laplace operator; u is the flow velocity of underground water, m/s; kappa is the permeability of the aqueous layer, m2(ii) a Mu is dynamic viscosity of water, Pa.s; p is water pressure, Pa; t is time, s; g is the acceleration of gravity, m/s2；QmIs a water flow source;
step two: determining a simulation range of a hydrophobic aquifer and processing a range boundary;
step three: constructing and discretizing a composite numerical model of the hydrophobic aquifer and the oblique hydrophobic drilling;
step four: treating the overflow boundary of the hydrophobic aquifer and the borehole wall, wherein the total water head of the aquifer at any point is defined as the following formula (3) according to the dynamics principle of the underground water:
H＝z+p/r+u2/2g (3)
in the formula: h is a certain water head value (m); z is the position head (m); p is water pressure (MPa) and r is groundwater volume weight (1000N/m)3) P/r is called pressure head; u is the groundwater flow velocity (m/s) and g is the gravitational acceleration (m/s) 2)，u2The/2 g is the velocity head;
step five: inputting parameters of a hydrophobic aquifer, and defining two hydrogeological parameters of a permeability coefficient and a water supply degree of the hydrophobic aquifer in a model;
step six: calculating the water inflow of the hydrophobic borehole, setting a solver as a transient process, setting a solving step length and solving time according to the actual numerical calculation requirement, finally performing unsteady flow simulation calculation, and performing real-time integration, namely Q, on Darcy flow velocity U in the wall area of the hydrophobic boreholeSurge of＝∫∫UdΩArea of pore wallAnd the darcy seepage flow obtained by dynamic integration is the water inflow of the drilled hole.
Wherein: and in the second step, only establishing a hydrophobic aquifer and hydrophobic borehole composite numerical model within the coverage range of the coal face by using a finite element model according to the spatial structure of the coal face and the roof aquifer.
Wherein: the values at the periphery of the hydrophobic aquifer are processed into a 'large-range' infinitely-spread water-filled aquifer by using an infinite definition method, and the values at the top and the bottom of the hydrophobic aquifer are processed into a 'zero' flux boundary.
Wherein: and in the third step, constructing a hydrophobic borehole according to the design parameters of the cylindrical hydrophobic borehole spatial structure, and constructing a hydrophobic aquifer by taking the coverage of the coal face as a boundary according to the size of the coal face.
Wherein: a computer model compositely depicting an aquifer and a drilled hole on the coal face scale is established by utilizing a triangular tetrahedron unit subdivision method of a finite element model, 1/3 of the aperture size of the hydrophobic drilled hole is taken as the minimum unit subdivision standard, and the wall of the hydrophobic drilled hole is locally and finely subdivided.
According to the above contents, the method for predicting the water inflow of the underground inclined hydrophobic borehole of the coal mine has the following effects:
1) a Darcy unsteady seepage mathematical model is adopted to describe a method for describing the process of moving the underground water of the hydrophobic aquifer to the hydrophobic drilling hole, and the bottleneck that the water inflow amount of the drilling hole is difficult to dynamically predict in the process of evacuating the underground water of the aquifer by the underground upward inclined drilling hole of the coal mine is broken through.
2) The finite element subdivision unit infinite definition method is utilized to process the peripheral numerical value of the water-filled aquifer into a large-range infinitely-distributed water-filled aquifer, so that the influence of a small-range artificial water head boundary and a flow boundary on the prediction precision is reduced, the subdivision of the model unit is also reduced, the mesh subdivision quality is improved, and the numerical value of the top and the bottom plate of the hydrophobic aquifer is processed into a zero-flux boundary.
3) In a finite element analysis platform, the wall of a hydrophobic drilling hole is generalized into a seepage overflow boundary of an aquifer, and by adopting the method for defining the model solution condition based on the seepage overflow boundary piece, the simulation result is closer to a real seepage field, so that the problem that the drilling flow state is difficult to numerically depict is reasonably solved.
The details of the present invention can be obtained from the following description and the attached drawings.
Drawings
Fig. 1A and 1B show schematic views of the present invention of a tilted hydrophobic borehole flood process.
Fig. 2 shows a schematic of the discretization of a hydrophobic aquifer with a hydrophobic borehole according to the invention.
FIG. 3 shows a schematic of the hydrophobic aquifer of the present invention and the boundary of the hydrophobic borehole wall seepage overflow.
FIG. 4 shows a schematic diagram of a fitting curve of calculated water inflow and measured water inflow for a hydrophobic borehole of a working face according to the present invention.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be understood that when the terms "comprises" and "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and or combinations thereof.
The method for predicting the water inflow of the underground inclined hydrophobic borehole of the coal mine comprises the following steps:
the method comprises the following steps: selecting a mathematical model of movement of groundwater of an aquifer to a borehole, and describing the movement process of the groundwater of a hydrophobic aquifer to the hydrophobic borehole by adopting a Darcy unsteady seepage mathematical model, wherein the mathematical model is represented by the following formula (1) and formula (2):
in the formula:pis the porosity of the water-containing layer; rho is the density of water, kg/m3；
Is Laplace operator; u is the flow velocity of underground water, m/s; kappa is the permeability of the aqueous layer, m2(ii) a Mu is dynamic viscosity of water, Pa.s; p is water pressure, Pa; t is time, s; g is the acceleration of gravity, m/s2；QmIs a source of water flow.
Step two: the method comprises the steps of determining a hydrophobic aquifer simulation range and processing a range boundary, wherein the influence of an artificially given boundary condition on a coal face and a drill hole small-scale model on drill hole water burst analysis is large, and only a hydrophobic aquifer and hydrophobic drill hole composite numerical model in a coal face coverage range is established by utilizing a finite element model according to a space structure of a coal face and a roof aquifer because the scale of the coal face and drill hole scale model is very small compared with the scale of a traditional numerical simulation range of a groundwater system (the traditional groundwater numerical simulation takes a regional hydrogeological unit as a simulation range) and the influence of drill hole drainage on the aquifer is limited, as shown in figure 2. And (3) processing the peripheral numerical value of the hydrophobic aquifer into a large-range infinitely-spread water-filled aquifer by utilizing an infinite definition method so as to reduce the influence of a small-range artificial water head boundary and a flow boundary and reduce the subdivision of a model unit. Values were processed to "zero" flux boundaries at the top and bottom of the hydrophobic aquifer.
Step three: constructing and discretizing a composite numerical model of the hydrophobic aquifer and the elevation-inclination hydrophobic borehole, constructing the hydrophobic borehole according to the design parameters (length, elevation angle, azimuth angle and aperture) of the cylindrical hydrophobic borehole spatial structure, and constructing the hydrophobic aquifer by taking the coverage of the coal face as a boundary according to the size of the coal face; as the aperture of the hydrophobic drilling hole is generally smaller (centimeter level) on the scale of the coal face and is too different from the scale (hundred level) of the coal face, the quadrangular hexahedral model subdivision is difficult to carry out, as shown in figure 2, a triangular tetrahedron unit subdivision method of a finite element model is utilized to establish a computer model for compositely depicting the aquifer and the drilling hole on the scale of the coal face, 1/3 of the aperture size of the hydrophobic drilling hole is a minimum unit subdivision standard, the hole wall of the hydrophobic drilling hole is locally and finely subdivided, wherein in the setting of the size of the grid unit, the size of the network unit is calibrated to be fluid dynamics, and the quality of the whole model network subdivision unit is improved.
Step four: and (3) treating the overflow boundary of the hydrophobic aquifer and the wall of the drilled hole, wherein the underground hydrophobic drilled hole is a through type water passing channel, and when the underground drilled hole is completely opened, because the underground water of the hydrophobic aquifer seeps to the wall of the hydrophobic drilled hole and then is discharged out of the hole in a free flow mode, seeped water is difficult to form a pressure head in the drilled hole. The total head at any point of the aquifer is defined according to the dynamics principle of the groundwater as the following formula (3):
H＝z+p/r+u2/2g (3)
In the formula: h is a certain water head value (m); z is the position head (m); p is water pressure (MPa) and r is groundwater volume weight (1000N/m)3) P/r is called pressure head; u is the groundwater flow velocity (m/s) and g is the gravitational acceleration (m/s)2)，u2The/2 g is the velocity head.
The wall of the hydrophobic drill hole can be used as an overflow boundary of the seepage of a water-filled aquifer, according to the above formula, on the seepage overflow boundary of the aquifer, the seepage speed of underground water is slow according to the flow speed continuous principle, so that in the above formula, u can be ignored when the total head on the seepage overflow boundary is calculated2A water head term of speed of 2 g; in addition, because the hydrophobic drilling hole is communicated with the atmosphere, the pore water pressure of the interface is approximately equal to the atmospheric pressure (0.1MPa), and the p/r pressure head is an extremely small fixed value (10)-4m). Therefore, the height H of the groundwater head on the Darcy seepage overflow boundary of the hole wall is approximately equal to the position elevation z of each subdivision node of the hole wall and the constant pressure water head value of p/r (10)- 4m), i.e. H ═ z +10-4. As shown in FIG. 3, in the finite element analysis platform, the wall of the hydrophobic borehole can be generalized into the seepage overflow boundary of the aquifer, and the simulation of the definition method of the solution condition based on the seepage overflow condition is closer to the real seepage field by adopting the definition method of the solution condition based on the seepage overflow conditionThe problem that the drilling flow state is difficult to figure is reasonably solved.
Step five: and (3) inputting parameters of the hydrophobic aquifer, and defining two hydrogeological parameters of the permeability coefficient and the water supply degree of the hydrophobic aquifer in the model according to the field measured data.
Step six: calculating the water inflow of the drainage borehole, setting a solver as a transient process, setting a solving step length and solving time according to the numerical calculation actual demand, and finally performing unsteady flow simulation calculation, as shown in fig. 3. By integrating the Darcy flow velocity U in the wall region of a hydrophobic borehole in real time, i.e. QSurge of＝∫∫UdΩArea of pore wallAnd the darcy seepage flow obtained by dynamic integration is the water inflow of the drilled hole.
The invention is further explained by taking a certain first mining working face of a Binxian mining area as an example and combining the drawings and the embodiment.
The method comprises the following steps: selecting a mathematical model of the movement of the groundwater of the aquifer to the drill hole, and describing the movement process of the groundwater of the hydrophobic aquifer to the hydrophobic drill hole by adopting a Darcy unsteady seepage mathematical model:
in the formula:pis the porosity of the water-containing layer; rho is the density of water, kg/m3；
Is Laplace operator; u is the flow velocity of underground water, m/s; kappa is the permeability of the aqueous layer, m2(ii) a Mu is dynamic viscosity of water, Pa.s; p is water pressure, Pa; t is time, s; g is the acceleration of gravity, m/s 2；QmIs a source of water flow.
Step two: simulation range determination and range boundary treatment, wherein the size of a coal face is inclined length 500m and face width 150m, a hydrophobic aquifer is composed of fine-grained sandstone (thickness 13m), sandy mudstone (thickness 23m) and medium-coarse sandstone (thickness 36m) layers above and below, an aquifer hydrophobic drilling prediction model in the range of 150 x 500m of the coal face is established, as shown in figure 2, the numerical value of the periphery of the water-filled aquifer is treated into a large-range infinite-spread water-filled aquifer by using an infinite definition method, and the numerical values of the top and the bottom of the hydrophobic aquifer are treated into a zero-flux boundary.
Step three: constructing and discretizing a numerical model of a hydrophobic aquifer and a hydrophobic borehole, wherein in the embodiment, the azimuth angle of the hydrophobic borehole is 228 degrees, the inclination angle is 55 degrees, the aperture is 94mm, the inclination length is 85m (the hydrophobic aquifer is not penetrated), the hydrophobic borehole is constructed, and the hydrophobic aquifer is constructed by taking 150 x 500m coverage of a coal face as a boundary according to the size of the coal face; the method comprises the steps of establishing a computer model compositely carved by a hydrophobic aquifer and a hydrophobic drilling hole in the embodiment by adopting a finite element triangular tetrahedron unit subdivision method, taking 1/3 of the aperture of the hydrophobic drilling hole as a subdivision standard, taking the minimum size of 31.3mm as a subdivision standard, and carrying out local fine subdivision on the wall of the hydrophobic drilling hole, wherein in the setting of the size of a grid unit, the size of the network unit is calibrated to be fluid dynamics, and the quality of the network subdivision unit of the whole model is improved.
Step four: treating the overflow boundary of the aquifer and the borehole wall, defining the hole wall of the hydrophobic borehole as the overflow boundary of the seepage of the water-filled aquifer, and enabling the height H of the groundwater head on the Darcy seepage overflow boundary of the hole wall to be equal to the position elevation z and the p/r constant pressure head value (10)-4m), i.e. H ═ z +10-4。
Step five: the method comprises the following steps of inputting parameters of a hydrophobic aquifer, and defining two hydrogeological parameters of the permeability coefficient of the hydrophobic aquifer and the water supply degree in a model according to data actually measured on site, wherein the two hydrogeological parameters are shown in the following table 1.
TABLE 1 model parameters
Step six: calculating the water inflow of the hydrophobic borehole, setting a solver as a transient process, setting a solving step length and solving time according to the actual numerical calculation requirement, and finally performing unsteady flow simulation calculation, wherein the model takes 0.1h as a time step length, and the darcy seepage flow obtained through calculation is the water inflow of the borehole by performing real-time integration on the darcy flow velocity U in the wall area of the hydrophobic borehole. The curve of the change process of the water inflow of the drilled hole and the actually measured water inflow is obtained by calculation and is shown in fig. 4, the embodiment simulates the calculated water inflow of the drilled hole by fitting analysis for 0-30d, and the attenuation rule of the water inflow of the drilled hole accords with a first-order single exponential decay process, and the following formula (4) is adopted:
Q＝42.82+14.02*exp(-2.03*t) (4)
wherein the fitted stable water amount Q e＝42.82m3The stable period is about 41h, the attenuation coefficient a of the water inflow of the drill hole is 2.03, and the fitting determination coefficient reaches R2＝0.93。
Through the embodiment, the method for predicting the change process of the water inflow of the underground inclined hydrophobic borehole of the coal mine is scientific and practical.
Therefore, the beneficial effects of the invention are as follows:
1) a Darcy unsteady seepage mathematical model is adopted to describe a method for describing the process of moving the underground water of the hydrophobic aquifer to the hydrophobic drilling hole, and the bottleneck that the water inflow amount of the drilling hole is difficult to dynamically predict in the process of evacuating the underground water of the aquifer by the underground upward inclined drilling hole of the coal mine is broken through.
2) The finite element subdivision unit infinite definition method is utilized to process the peripheral numerical value of the water-filled aquifer into a large-range infinitely-distributed water-filled aquifer, so that the influence of a small-range artificial water head boundary and a flow boundary on the prediction precision is reduced, the subdivision of the model unit is also reduced, the mesh subdivision quality is improved, and the numerical value of the top and the bottom plate of the hydrophobic aquifer is processed into a zero-flux boundary.
3) In a finite element analysis platform, the wall of a hydrophobic drilling hole is generalized into a seepage overflow boundary of an aquifer, and by adopting the method for defining the model solution condition based on the seepage overflow boundary piece, the simulation result is closer to a real seepage field, so that the problem that the drilling flow state is difficult to numerically depict is reasonably solved.
It should be apparent that the foregoing description and illustrations are by way of example only and are not intended to limit the present disclosure, application or uses. While embodiments have been described in the embodiments and depicted in the drawings, the present invention is not limited to the particular examples illustrated by the drawings and described in the embodiments as the best mode presently contemplated for carrying out the teachings of the present invention, and the scope of the present invention will include any embodiments falling within the foregoing description and the appended claims.
Claims (5)
1. A method for predicting water inflow of an underground oblique hydrophobic borehole of a coal mine is characterized by comprising the following steps:
the method comprises the following steps: the selection of a mathematical model of the movement of the groundwater of the aquifer to the borehole is described by adopting a Darcy unsteady seepage mathematical model, such as the following formula (1) and formula (2):
in the formula:pis the porosity of the water-containing layer; rho is the density of water, kg/m3(ii) a ^ is Laplacian; u is the flow velocity of underground water, m/s; kappa is the permeability of the aqueous layer, m2(ii) a Mu is dynamic viscosity of water, Pa.s; p is water pressure, Pa; t is time, s; g is the acceleration of gravity, m/s2；QmIs a water flow source;
step two: determining a simulation range of a hydrophobic aquifer and processing a range boundary;
step three: constructing and discretizing a composite numerical model of the hydrophobic aquifer and the oblique hydrophobic drilling;
Step four: treating the overflow boundary of the hydrophobic aquifer and the borehole wall, wherein the total water head of the aquifer at any point is defined as the following formula (3) according to the dynamics principle of the underground water:
H＝z+p/r+u2/2g(3)
in the formula: h is a certain water head value (m); z is the position head (m); p is water pressure (MPa) and r is groundwater volume weight (1000N/m)3) P/r is called pressure head;u is the groundwater flow velocity (m/s) and g is the gravitational acceleration (m/s)2)，u2The/2 g is the velocity head;
step five: inputting parameters of a hydrophobic aquifer, and defining two hydrogeological parameters of a permeability coefficient and a water supply degree of the hydrophobic aquifer in a model;
step six: calculating the water inflow of the hydrophobic borehole, setting a solver as a transient process, setting a solving step length and solving time according to the actual numerical calculation requirement, finally performing unsteady flow simulation calculation, and performing real-time integration, namely Q, on Darcy flow velocity U in the wall area of the hydrophobic boreholeSurge of＝∫∫UdΩArea of pore wallAnd the darcy seepage flow obtained by dynamic integration is the water inflow of the drilled hole.
2. The method for predicting the water inflow of the underground oblique hydrophobic borehole of the coal mine according to claim 1, wherein: and in the second step, only establishing a hydrophobic aquifer and hydrophobic borehole composite numerical model within the coverage range of the coal face by using a finite element model according to the spatial structure of the coal face and the roof aquifer.
3. The method for predicting the water inflow of the underground oblique hydrophobic borehole of the coal mine according to claim 2, wherein: the values at the periphery of the hydrophobic aquifer are processed into a 'large-range' infinitely-spread water-filled aquifer by using an infinite definition method, and the values at the top and the bottom of the hydrophobic aquifer are processed into a 'zero' flux boundary.
4. The method for predicting the water inflow of the underground oblique hydrophobic borehole of the coal mine according to claim 1, wherein: and in the third step, constructing a hydrophobic borehole according to the design parameters of the cylindrical hydrophobic borehole spatial structure, and constructing a hydrophobic aquifer by taking the coverage of the coal face as a boundary according to the size of the coal face.
5. The method for predicting the water inflow of the underground oblique hydrophobic borehole of the coal mine according to claim 4, wherein: a computer model compositely depicting an aquifer and a drilled hole on the coal face scale is established by utilizing a triangular tetrahedron unit subdivision method of a finite element model, 1/3 of the aperture size of the hydrophobic drilled hole is taken as the minimum unit subdivision standard, and the wall of the hydrophobic drilled hole is locally and finely subdivided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010692059.7A CN111859751B (en) | 2020-07-17 | 2020-07-17 | Method for predicting water inflow of underground coal mine inclined drainage drilling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010692059.7A CN111859751B (en) | 2020-07-17 | 2020-07-17 | Method for predicting water inflow of underground coal mine inclined drainage drilling |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111859751A true CN111859751A (en) | 2020-10-30 |
| CN111859751B CN111859751B (en) | 2023-10-24 |
Family
ID=73000534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010692059.7A Active CN111859751B (en) | 2020-07-17 | 2020-07-17 | Method for predicting water inflow of underground coal mine inclined drainage drilling |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111859751B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112502775A (en) * | 2020-11-06 | 2021-03-16 | 扎赉诺尔煤业有限责任公司 | Semi-consolidated sandstone aquifer dewatering and pressure reducing method |
| CN118245725A (en) * | 2024-05-29 | 2024-06-25 | 北京联创高科信息技术有限公司 | Coal mine accumulated water inflow calculating method based on function fitting and mathematical integration |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103226732A (en) * | 2013-03-21 | 2013-07-31 | 中南大学 | GMS (groundwater modeling system)-based forecast method for ground water seepage fields at different mining levels of mining area |
| JP2018154969A (en) * | 2017-03-15 | 2018-10-04 | 大成建設株式会社 | Method for estimating spring water pressure of natural ground |
| CN109723424A (en) * | 2018-12-11 | 2019-05-07 | 中煤科工集团西安研究院有限公司 | A kind of down-hole drilling waterdrainage amount prediction technique |
-
2020
- 2020-07-17 CN CN202010692059.7A patent/CN111859751B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103226732A (en) * | 2013-03-21 | 2013-07-31 | 中南大学 | GMS (groundwater modeling system)-based forecast method for ground water seepage fields at different mining levels of mining area |
| JP2018154969A (en) * | 2017-03-15 | 2018-10-04 | 大成建設株式会社 | Method for estimating spring water pressure of natural ground |
| CN109723424A (en) * | 2018-12-11 | 2019-05-07 | 中煤科工集团西安研究院有限公司 | A kind of down-hole drilling waterdrainage amount prediction technique |
Non-Patent Citations (6)
| Title |
|---|
| 刘永良;潘国营;: "基于Visual Modflow的岩溶水疏降流场模拟和涌水量预测", 河南理工大学学报(自然科学版), no. 01 * |
| 刘英锋;郭小铭;: "导水裂缝带部分波及顶板含水层条件下涌水量预测", 煤田地质与勘探, no. 05 * |
| 孙启明;柯贤敏;田国林;王玮;: "基于渗流井理论的放水试验数值模拟及水文地质参数不确定性分析", 水土保持通报, no. 03 * |
| 张保建;: "基于Visual Modflow的台格庙勘查区矿井涌水量预测", 煤炭科学技术, no. 1 * |
| 李平;郭会荣;吴孔军;靳孟贵;李学问;: "王河煤矿矿井涌水量数值模拟及预测", 地球科学(中国地质大学学报), no. 04 * |
| 郭小铭;: "基于排水沟数值模型的工作面涌水量预测", 煤矿安全, no. 01 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112502775A (en) * | 2020-11-06 | 2021-03-16 | 扎赉诺尔煤业有限责任公司 | Semi-consolidated sandstone aquifer dewatering and pressure reducing method |
| CN118245725A (en) * | 2024-05-29 | 2024-06-25 | 北京联创高科信息技术有限公司 | Coal mine accumulated water inflow calculating method based on function fitting and mathematical integration |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111859751B (en) | 2023-10-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Clemens et al. | A combined continuum and discrete network reactive transport model for the simulation of karst development | |
| CN103455667B (en) | Aeration administers the method for numerical simulation of artesian aquifer seawater invasion | |
| CN111859751A (en) | Method for predicting water inflow of underground inclined hydrophobic borehole of coal mine | |
| CN111859256B (en) | Water-disaster space-time control drainage control method for roof of coal face | |
| Clemens et al. | Simulation of the development of karst aquifers: role of the epikarst | |
| CN104533519B (en) | Management method for water burst water disasters in event of vertical shaft wellbore passing through strong water-containing thick rock layer | |
| CN114880962B (en) | Stratum seepage-wellbore pipe flow coupling-based tight gas reservoir single well injection and production capacity integrated analysis method | |
| CN108532617B (en) | Heterogeneous water table aquifer suspended cutoff foundation pit determines water level and draws water method for determination of amount | |
| Simmons et al. | Modelling density-dependent flow and solute transport at the Lake Tutchewop saline disposal complex, Victoria | |
| CN111767670A (en) | Aquifer geological parameter inversion method based on underground elevation and inclination single-hole water discharge test | |
| Shi et al. | Optimal design and dynamic control of construction dewatering with the consideration of dewatering process | |
| CN116467958A (en) | Salt lake brine numerical model construction and water supplementing and mineral dissolving efficiency calculation method | |
| CN112685970B (en) | Quantitative characterization method and system for seepage interface of flow unit of water-drive reservoir | |
| Zhang et al. | Withdrawal of layered fluid through a line sink in a porous medium | |
| CN107989598A (en) | Bottom water reservoir straight well water cone falls the Forecasting Methodology of height after rise | |
| Shao et al. | Coupling a 1D dual-permeability model with an infinite slope stability approach to quantify the influence of preferential flow on slope stability | |
| Polomčić et al. | Hydrodynamic model of the open-pit mine “Buvač”(Republic of Srpska) | |
| Vauclin | Flow of water and air in soils: Theoretical and experimental aspects | |
| Sunjoto | The inventions technology on water resources to support environmental engineering based infrastructure | |
| Snee et al. | Prediction of compressed air leakage from tunnels | |
| Vauclin | Infiltration in unsaturated soils | |
| WO2014190262A1 (en) | Method for monitoring the drilling of a well using a floating drilling rig and associated monitoring system | |
| Klimchouk | Evolution of karst in evaporites | |
| Lewis et al. | Numerical simulation of low-flow bulkheads to reduce uncontrolled discharge from an underground copper mine | |
| Åberg | Pressure distribution around stationary gas bubbles in water-saturated rock |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |