CN110610041A - Method for judging limit strain of instability and damage of shaft - Google Patents
Method for judging limit strain of instability and damage of shaft Download PDFInfo
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- CN110610041A CN110610041A CN201910847379.2A CN201910847379A CN110610041A CN 110610041 A CN110610041 A CN 110610041A CN 201910847379 A CN201910847379 A CN 201910847379A CN 110610041 A CN110610041 A CN 110610041A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D7/00—Shaft equipment, e.g. timbering within the shaft
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D7/00—Shaft equipment, e.g. timbering within the shaft
- E21D7/005—Determination of shaft lining deformation
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T17/00—Three dimensional [3D] modelling, e.g. data description of 3D objects
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- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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Abstract
A method for judging limit strain of wellbore instability damage comprises the following steps: (1) establishing a simulation calculation model, and calculating the plastic limit strain of the rock mass; (2) establishing a refined three-dimensional geological model, and reproducing a geological environment; (3) monitoring strain information of a wellbore; (4) giving out a reasonable calculation model of the shaft under the influence of multiple factors; (5) giving the initial head reduction height of the model, obtaining an initial reduction coefficient K, reducing the well walls c and phi, and bringing the well walls c and phi into the calculation model reversely to see whether a region larger than the limit strain appears; (6) performing strength reduction on the units exceeding the limit strain in the well wall; (7) and recording the reduction coefficient, namely the safety coefficient of the current water level well wall. The method for judging the limit strain of the instability and damage of the shaft provides a theoretical basis for mine technicians to evaluate the stability of the shaft.
Description
Technical Field
The invention belongs to the field of industries such as petroleum and natural gas drilling, geological exploration and mine drilling, relates to a method for judging damage of shaft stability, and particularly relates to a method for judging limit strain of shaft instability damage of a mine shaft.
Background
The damage that the shaft pit shaft takes place not only has the tension and compression to destroy, and the shearing is destroyed in addition, and the form of destruction is diversified, and the biggest characteristic shows to be the annular fracture of wall of a well concrete, forms a horizontal fracture area in circular concrete well wall inboard promptly, and the concrete drops in the fracture area in one piece to can see the reinforcing bar of dropping department and to the inboard bending of wall of a well, this shows that the concrete in the high stress rupture district leads to its emergence plasticity limit to destroy because of unable too big compressive stress and the shearing stress of bearing.
In the conventional research, the critical value of the well wall strain is used as the criterion of the instability failure of the shaft, but the conventional knowledge and the criterion are mostly derived by the failure criterion of the concrete well wall in the elastic phase. Through continuous monitoring information of a mine well wall monitoring system for twenty years, strain values of monitoring points of a well wall part are far beyond the derived values based on the elastic phase. Thus, although there is no damage to the wellbore at the mine site, there is no way to determine at all which stage of the stabilization process the wellbore is in, and whether or not it needs to be treated with sound measures.
Under the environment, a method for judging instability damage of shaft engineering is urgently needed, the stability of a shaft is evaluated, the protruding problem that an actual monitoring strain value does not accord with a theoretical value is eliminated, and theoretical and practical judgment basis is provided for mine field workers.
Disclosure of Invention
In order to solve the problems, the invention provides a method for judging the limit strain of the instability and damage of the shaft, which provides a theoretical basis for mine technicians to evaluate the stability of the shaft.
The invention adopts the technical scheme to solve the technical problems that the method for judging the ultimate strain of the instability and damage of the shaft comprises the following steps:
(1) establishing simulation calculation models of well wall concrete and different surrounding rock and soil materials, and respectively calculating plastic limit strains of the different rock materials by using an overload method;
(2) establishing a refined three-dimensional geological model by combining structural design materials of the shaft and geological exploration data of a mining area near the shaft, and truly reproducing geological environments of the shaft and the mining area near the shaft as far as possible;
(3) arranging the same monitoring points at the same positions of the inverse analysis model by combining the arrangement positions of different monitoring points of the shaft monitoring system, and monitoring the strain information of the shaft;
(4) establishing an optimal combination of influence factors inducing wellbore instability by comparing influence weights of wellbore stability influence factors, and then carrying out inverse analysis to give a reasonable calculation model of the wellbore under the influence of multiple factors;
(5) giving the initial head reduction height of the model, obtaining an initial reduction coefficient K, reducing the well walls c and phi, and bringing the well walls c and phi into the calculation model reversely to see whether a region larger than the limit strain appears; if the calculation result shows that no unit larger than the value exists, the reduction coefficient is continuously increased until the well wall exceeds the strain limit value unit;
(6) taking the previous calculation file as an initial calculation file, carrying out intensity reduction on the units exceeding the ultimate strain in the well wall, observing and recording whether a new area of the well wall with the ultimate strain appears or not after the calculation is finished, taking the calculation as the initial file of the next calculation, and carrying out reduction on the new units with the ultimate strain again, wherein the reduction step length is 0.01 each time;
(7) and (3) forming a plastic through area in the well wall unit finally along with the increase of the units exceeding the ultimate strain on the well wall, stopping calculation at the moment, and recording the reduction coefficient at the moment, namely the current water level lowering well wall safety coefficient.
Preferably, the influence weight in step (4) includes water level, temperature; in step (5), c is the cohesive force and phi is the internal friction angle.
In any of the above aspects, preferably, in the step (3), the monitoring of the strain information of the wellbore includes a plurality of circles of annular pressure relief grooves spaced apart in an axial direction on an inner wall of the mine wellbore, and the mine wellbore monitoring method includes: installing an annular force transmission steel ring with the shape matched with the surface of the wall of the shaft cylinder in a monitoring point arranged in the shaft, and installing a plurality of strain sensors on the annular force transmission steel ring and the monitoring point; acquiring a strain signal of the shaft in real time through the strain sensor; the strain signal is led into a data conversion unit outside the mine shaft; and the strain signal is converted by the data conversion unit and transmitted to a data acquisition device outside the mine shaft, so that the strain information of the mine shaft is monitored in real time.
In any of the above schemes, preferably, the strain sensor is a two-dimensional carbon composite nano metal film flexible strain sensor, and the thickness of the metal film is 550-600 μm.
In any of the above schemes, preferably, 4 installation points are arranged on each monitoring point along the up-down, left-right directions, each installation point is provided with the strain sensor, and strain signals of the shaft along the axial direction, the circumferential direction and the radial direction are respectively obtained by using the strain sensors.
In any of the above schemes, preferably, the establishing of the refined three-dimensional geological model in the step (2) includes a, collecting structural design materials of the shaft and geological exploration data of a mining area near the shaft, and performing information processing: performing three-dimensional and digital processing by using software, and extracting elevation information; clearing repeated points, bridging points and coalescing points in the elevation information file; constructing a digital earth surface model by using the line file;
b. constructing a geological information database; the geological information database comprises a drilling hole coordinate data file, a drilling inclination measuring data file, a sample test data file and a geological code data file; the data files are mutually independent, and the mutual relation is established through the serial numbers and is imported into the three-dimensional software to form a relational database;
c. calling the geological information database, displaying structural design materials of the drill holes and the shaft in a three-dimensional space, and screening out the drill holes contained in the section needing to be drawn currently in a mode of cutting the section along an exploration line or restraining the geological information database; according to the technical condition indexes of ore body mining, and in combination with the ore body circle connection rule, performing geological interpretation on the drill holes on the section, and circling the section ore body to generate a three-dimensional section ore body contour line;
d. carrying out extrapolation processing on the generated three-dimensional profile ore body contour line of each ore body according to the ore body pinch-out tendency and the correlation with the fault; connecting the profile contour lines of all ore bodies according to corresponding conditions, and generating a three-dimensional geological model of each ore body by adopting a triangulation network connection technology; and verifying and correcting the generated three-dimensional geological model.
The invention is obtained according to years of practical application practice and experience, adopts the best technical means and measures to carry out combined optimization, obtains the optimal technical effect, is not simple superposition and splicing of technical characteristics, and has obvious significance.
The invention has the beneficial effects that:
(1) the stress of the well wall concrete structure which does not accord with the shaft engineering is calculated based on the strain extreme value of the concrete test block in the elastic stage, and the calculation of the strain extreme value can be effectively optimized.
(2) The method fully considers the influence of different geological conditions on the extreme value of the concrete strain of the well wall, so that the calculation of the extreme value of the concrete strain is more accurate.
(3) The existing borehole wall instability prediction cannot give out instability damage positions and processes, and is only based on the summary of experience or tests.
(4) The accurate estimation of the borehole wall instability process can provide effective theoretical support for the evaluation, prediction and treatment of the safety state of the borehole wall in service period.
(5) The model modeling in the method can reduce the investment risk; the engineering quantity is saved, the mining cost is reduced, and the profit rate is improved; the resource utilization rate is improved, and national resources are not wasted.
Drawings
FIG. 1 is a schematic view of a simulation calculation model of ultimate strain of a geotechnical material established by the method for discriminating ultimate strain of wellbore instability damage according to the invention.
FIG. 2 is a schematic diagram of a geological model of the surrounding rock as close to reality as possible, which is established by the method for discriminating the limit strain of the instability and the damage of the shaft.
FIG. 3 is a cloud of calculated shear strains for dynamic local intensity reduction for a method of identifying extreme strain for wellbore destabilization failure according to the present invention, illustrating the failure process for an example wellbore project.
Detailed Description
The invention is further described with reference to the following figures and specific examples, but the scope of the claims is not limited thereto.
Example 1
Referring to fig. 1-3, a method for discriminating ultimate strain of wellbore instability damage includes the following steps:
(1) establishing a simulation calculation model (figure 1) of the well wall concrete and different surrounding rock and soil materials, and respectively calculating the plastic limit strains of the different rock materials by using an overload method (monitoring the limit strains of different points in the model figure 1).
(2) And establishing a refined three-dimensional geological model (figure 2) by combining the structural design material of the shaft and geological exploration data of the mining area near the shaft, and truly reproducing the geological environment of the shaft and the mining area near the shaft as far as possible.
(3) And (3) arranging the same monitoring points at the same positions of the inverse analysis model by combining the arrangement positions of different monitoring points of the shaft monitoring system, and monitoring the strain information of the shaft.
(4) By comparing the influence weights (water level, temperature and the like) of the stability influence factors of the shaft, the optimal combination of the influence factors inducing shaft instability is established, and then a reasonable calculation model of the shaft under the influence of multiple factors is given through inverse analysis.
(5) The influence of the water level is the dominant factor, the initial water head height reduction of the model is given, the initial reduction coefficient K is obtained, the well wall c and phi are reduced (formula 1), and the well wall c and phi are brought into the calculation model reversely to see whether the area larger than the limit strain area appears. If the calculation result shows that no unit is larger than the value, the reduction coefficient is continuously increased until the well wall exceeds the strain limit value unit.
Wherein c is cohesive force, phi is an internal friction angle, and K is a reduction coefficient.
(6) And transferring the previous calculation file as an initial calculation file, performing intensity reduction on the unit exceeding the ultimate strain in the well wall, observing and recording whether a new area of the well wall with the ultimate strain appears after the calculation is finished, taking the calculation as the initial file of the next calculation, performing reduction on the new unit with the ultimate strain appearing again, and taking the reduction step length of 0.01 each time.
(7) And (3) forming a plastic through area in the well wall unit finally along with the increase of the units exceeding the ultimate strain on the well wall, stopping calculation at the moment, and recording the reduction coefficient at the moment, namely the current water level lowering well wall safety coefficient.
Example 2
Referring to fig. 1-3, a method for discriminating ultimate strain of wellbore instability damage includes the following steps:
(1) establishing a simulation calculation model (figure 1) of the well wall concrete and different surrounding rock and soil materials, and respectively calculating the plastic limit strains of the different rock materials by using an overload method (monitoring the limit strains of different points in the model figure 1).
(2) And establishing a refined three-dimensional geological model (figure 2) by combining the structural design material of the shaft and geological exploration data of the mining area near the shaft, and truly reproducing the geological environment of the shaft and the mining area near the shaft as far as possible.
(3) And (3) arranging the same monitoring points at the same positions of the inverse analysis model by combining the arrangement positions of different monitoring points of the shaft monitoring system, and monitoring the strain information of the shaft.
(4) By comparing the influence weights (water level, temperature and the like) of the stability influence factors of the shaft, the optimal combination of the influence factors inducing shaft instability is established, and then a reasonable calculation model of the shaft under the influence of multiple factors is given through inverse analysis.
(5) The influence of the water level is the dominant factor, the initial water head height reduction of the model is given, the initial reduction coefficient K is obtained, the well wall c and phi are reduced (formula 1), and the well wall c and phi are brought into the calculation model reversely to see whether the area larger than the limit strain area appears. If the calculation result shows that no unit is larger than the value, the reduction coefficient is continuously increased until the well wall exceeds the strain limit value unit.
Wherein c is cohesive force, phi is an internal friction angle, and K is a reduction coefficient.
(6) And transferring the previous calculation file as an initial calculation file, performing intensity reduction on the unit exceeding the ultimate strain in the well wall, observing and recording whether a new area of the well wall with the ultimate strain appears after the calculation is finished, taking the calculation as the initial file of the next calculation, performing reduction on the new unit with the ultimate strain appearing again, and taking the reduction step length of 0.01 each time.
(7) And (3) forming a plastic through area in the well wall unit finally along with the increase of the units exceeding the ultimate strain on the well wall, stopping calculation at the moment, and recording the reduction coefficient at the moment, namely the current water level lowering well wall safety coefficient.
The influence weight in the step (4) comprises water level and temperature; in step (5), c is the cohesive force and phi is the internal friction angle.
In the step (3), monitoring the strain information of the shaft comprises that a plurality of rings of annular pressure relief grooves are arranged on the inner wall of the shaft at intervals along the axial direction, and the shaft monitoring method comprises the following steps: installing an annular force transmission steel ring with the shape matched with the surface of the wall of the shaft cylinder in a monitoring point arranged in the shaft, and installing a plurality of strain sensors on the annular force transmission steel ring and the monitoring point; acquiring a strain signal of the shaft in real time through the strain sensor; the strain signal is led into a data conversion unit outside the mine shaft; and the strain signal is converted by the data conversion unit and transmitted to a data acquisition device outside the mine shaft, so that the strain information of the mine shaft is monitored in real time.
The strain sensor is a two-dimensional carbon composite nano metal film flexible strain sensor, and the thickness of the metal film is 550-600 mu m.
4 mounting points are arranged on each monitoring point along the vertical and horizontal directions, each mounting point is provided with the strain sensor, and strain signals of the shaft along the axial direction, the circumferential direction and the radial direction are respectively obtained by using the strain sensors.
Establishing a refined three-dimensional geological model in the step (2), which comprises a, collecting structural design materials of a shaft and geological exploration data of a mining area near the shaft, and performing information processing: performing three-dimensional and digital processing by using software, and extracting elevation information; clearing repeated points, bridging points and coalescing points in the elevation information file; constructing a digital earth surface model by using the line file;
b. constructing a geological information database; the geological information database comprises a drilling hole coordinate data file, a drilling inclination measuring data file, a sample test data file and a geological code data file; the data files are mutually independent, and the mutual relation is established through the serial numbers and is imported into the three-dimensional software to form a relational database;
c. calling the geological information database, displaying structural design materials of the drill holes and the shaft in a three-dimensional space, and screening out the drill holes contained in the section needing to be drawn currently in a mode of cutting the section along an exploration line or restraining the geological information database; according to the technical condition indexes of ore body mining, and in combination with the ore body circle connection rule, performing geological interpretation on the drill holes on the section, and circling the section ore body to generate a three-dimensional section ore body contour line;
d. carrying out extrapolation processing on the generated three-dimensional profile ore body contour line of each ore body according to the ore body pinch-out tendency and the correlation with the fault; connecting the profile contour lines of all ore bodies according to corresponding conditions, and generating a three-dimensional geological model of each ore body by adopting a triangulation network connection technology; and verifying and correcting the generated three-dimensional geological model.
Example 3
Referring to fig. 1-3, a method for discriminating ultimate strain of wellbore instability damage includes the following steps:
(1) establishing a simulation calculation model (figure 1) of the well wall concrete and different surrounding rock and soil materials, and respectively calculating the plastic limit strains of the different rock materials by using an overload method (monitoring the limit strains of different points in the model figure 1).
(2) And establishing a refined three-dimensional geological model (figure 2) by combining the structural design material of the shaft and geological exploration data of the mining area near the shaft, and truly reproducing the geological environment of the shaft and the mining area near the shaft as far as possible.
(3) And (3) arranging the same monitoring points at the same positions of the inverse analysis model by combining the arrangement positions of different monitoring points of the shaft monitoring system, and monitoring the strain information of the shaft.
(4) By comparing the influence weights (water level, temperature and the like) of the stability influence factors of the shaft, the optimal combination of the influence factors inducing shaft instability is established, and then a reasonable calculation model of the shaft under the influence of multiple factors is given through inverse analysis.
(5) The influence of the water level is the dominant factor, the initial water head height reduction of the model is given, the initial reduction coefficient K is obtained, the well wall c and phi are reduced (formula 1), and the well wall c and phi are brought into the calculation model reversely to see whether the area larger than the limit strain area appears. If the calculation result shows that no unit is larger than the value, the reduction coefficient is continuously increased until the well wall exceeds the strain limit value unit.
Wherein c is cohesive force, phi is an internal friction angle, and K is a reduction coefficient.
(6) And transferring the previous calculation file as an initial calculation file, performing intensity reduction on the unit exceeding the ultimate strain in the well wall, observing and recording whether a new area of the well wall with the ultimate strain appears after the calculation is finished, taking the calculation as the initial file of the next calculation, performing reduction on the new unit with the ultimate strain appearing again, and taking the reduction step length of 0.01 each time.
(7) And (3) forming a plastic through area in the well wall unit finally along with the increase of the units exceeding the ultimate strain on the well wall, stopping calculation at the moment, and recording the reduction coefficient at the moment, namely the current water level lowering well wall safety coefficient.
The influence weight in the step (4) comprises water level and temperature; in step (5), c is the cohesive force and phi is the internal friction angle.
In the step (3), monitoring the strain information of the shaft comprises that a plurality of rings of annular pressure relief grooves are arranged on the inner wall of the shaft at intervals along the axial direction, and the shaft monitoring method comprises the following steps: installing an annular force transmission steel ring with the shape matched with the surface of the wall of the shaft cylinder in a monitoring point arranged in the shaft, and installing a plurality of strain sensors on the annular force transmission steel ring and the monitoring point; acquiring a strain signal of the shaft in real time through the strain sensor; the strain signal is led into a data conversion unit outside the mine shaft; and the strain signal is converted by the data conversion unit and transmitted to a data acquisition device outside the mine shaft, so that the strain information of the mine shaft is monitored in real time.
The strain sensor is a two-dimensional carbon composite nano metal film flexible strain sensor, and the thickness of the metal film is 550-600 mu m.
4 mounting points are arranged on each monitoring point along the vertical and horizontal directions, each mounting point is provided with the strain sensor, and strain signals of the shaft along the axial direction, the circumferential direction and the radial direction are respectively obtained by using the strain sensors.
Establishing a refined three-dimensional geological model in the step (2), which comprises a, collecting structural design materials of a shaft and geological exploration data of a mining area near the shaft, and performing information processing: performing three-dimensional and digital processing by using software, and extracting elevation information; clearing repeated points, bridging points and coalescing points in the elevation information file; constructing a digital earth surface model by using the line file;
b. constructing a geological information database; the geological information database comprises a drilling hole coordinate data file, a drilling inclination measuring data file, a sample test data file and a geological code data file; the data files are mutually independent, and the mutual relation is established through the serial numbers and is imported into the three-dimensional software to form a relational database;
c. calling the geological information database, displaying structural design materials of the drill holes and the shaft in a three-dimensional space, and screening out the drill holes contained in the section needing to be drawn currently in a mode of cutting the section along an exploration line or restraining the geological information database; according to the technical condition indexes of ore body mining, and in combination with the ore body circle connection rule, performing geological interpretation on the drill holes on the section, and circling the section ore body to generate a three-dimensional section ore body contour line;
d. carrying out extrapolation processing on the generated three-dimensional profile ore body contour line of each ore body according to the ore body pinch-out tendency and the correlation with the fault; connecting the profile contour lines of all ore bodies according to corresponding conditions, and generating a three-dimensional geological model of each ore body by adopting a triangulation network connection technology; and verifying and correcting the generated three-dimensional geological model.
In addition, in order to further improve the effect, the preparation method of the two-dimensional carbon composite nano metal film flexible strain sensor comprises the following steps:
s1, cleaning the silver foil with cleaning solution, placing the silver foil in the middle of a quartz tube of the tube furnace, starting a vacuum pump, heating the tube furnace to 900-1000 ℃ in a nitrogen atmosphere of 10-15sccm, wherein the heating rate is 10-15 ℃/min; and when the temperature of the silver foil reaches 900-1000 ℃, introducing 30-40sccm of carbone into the quartz tube, keeping for 10-20min, closing the carbone, and cooling along with the furnace under the nitrogen atmosphere to obtain single-layer graphene on the silver foil to generate the silver-based graphene.
S2, selecting one side of the silver-based graphene, which is not attached to a quartz tube when the silver-based graphene grows, to spin-coat organic glass, placing the silver-based graphene which is spin-coated on the organic glass in an oven at 65-70 ℃ for curing the organic glass, soaking the cured silver-based graphene in 1-1.5mol/L FeCl3 solution, floating the organic glass film with the graphene on the solution surface after the silver-based graphene is dissolved, fishing up the organic glass film with the graphene by using an organic silicon film with the pre-stretching strain of 80-100%, and cleaning the organic glass film in deionized water to thoroughly remove residual FeCl3 and other impurities. And (3) dripping the acetketone on the organic silicon film with the graphene and the organic glass, repeatedly and thoroughly removing the organic glass for 2-3 times, leaving the organic silicon film compounded with the graphene, cleaning the organic silicon film compounded with the graphene with ethanol, and then drying the organic silicon film compounded with the graphene with nitrogen.
S3, placing the organic silicon film compounded with the graphene into a small magnetron sputtering instrument, placing a copper target into the sputtering instrument, starting a vacuum pump, introducing nitrogen after the vacuum degree reaches 5-7Pa, controlling the discharge current by adjusting the introduction amount of the protective atmosphere, starting the sputtering instrument when the discharge current reaches 20-25mA, and closing the sputtering instrument after sputtering for 700-800S to take out the graphene composite nano-copper film.
And S4, coating silver paste on two ends of the graphene composite nano copper film, and connecting copper leads to obtain the two-dimensional carbon composite nano metal film flexible strain sensor.
According to the invention, a magnetron sputtering technology is utilized to sputter a nano-copper particle film on the surface of graphene, and the flexible strain sensor is assembled, and the strain sensor can simultaneously improve the sensitivity and the cycle performance. The method has the advantages of simple process, easy operation, low cost, good controllability, large-scale production and the like.
In addition, in order to achieve better technical effects, the technical solutions in the above embodiments may be combined arbitrarily to meet various requirements of practical applications.
According to the embodiment, the stress of the well wall concrete structure which does not conform to the shaft engineering is calculated based on the strain extreme value of the concrete test block in the elastic stage, and the calculation of the strain extreme value can be effectively optimized.
The method fully considers the influence of different geological conditions on the extreme value of the concrete strain of the well wall, so that the calculation of the extreme value of the concrete strain is more accurate.
The existing borehole wall instability prediction cannot give out instability damage positions and processes, and is only based on the summary of experience or tests.
The accurate estimation of the borehole wall instability process can provide effective theoretical support for the evaluation, prediction and treatment of the safety state of the borehole wall in service period.
The model modeling in the method can reduce the investment risk; the engineering quantity is saved, the mining cost is reduced, and the profit rate is improved; the resource utilization rate is improved, and national resources are not wasted.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.
Claims (6)
1. A method for judging limit strain of wellbore instability damage is characterized by comprising the following steps:
(1) establishing simulation calculation models of well wall concrete and different surrounding rock and soil materials, and respectively calculating plastic limit strains of the different rock materials by using an overload method;
(2) establishing a refined three-dimensional geological model by combining structural design materials of the shaft and geological exploration data of a mining area near the shaft, and truly reproducing geological environments of the shaft and the mining area near the shaft as far as possible;
(3) arranging the same monitoring points at the same positions of the inverse analysis model by combining the arrangement positions of different monitoring points of the shaft monitoring system, and monitoring the strain information of the shaft;
(4) establishing an optimal combination of influence factors inducing wellbore instability by comparing influence weights of wellbore stability influence factors, and then carrying out inverse analysis to give a reasonable calculation model of the wellbore under the influence of multiple factors;
(5) giving the initial head reduction height of the model, obtaining an initial reduction coefficient K, reducing the well walls c and phi, and bringing the well walls c and phi into the calculation model reversely to see whether a region larger than the limit strain appears; if the calculation result shows that no unit larger than the value exists, the reduction coefficient is continuously increased until the well wall exceeds the strain limit value unit;
(6) taking the previous calculation file as an initial calculation file, carrying out intensity reduction on the units exceeding the ultimate strain in the well wall, observing and recording whether a new area of the well wall with the ultimate strain appears or not after the calculation is finished, taking the calculation as the initial file of the next calculation, and carrying out reduction on the new units with the ultimate strain again, wherein the reduction step length is 0.01 each time;
(7) and (3) forming a plastic through area in the well wall unit finally along with the increase of the units exceeding the ultimate strain on the well wall, stopping calculation at the moment, and recording the reduction coefficient at the moment, namely the current water level lowering well wall safety coefficient.
2. The method of claim 1, wherein the impact weight in step (4) includes water level, temperature; in step (5), c is the cohesive force and phi is the internal friction angle.
3. The method for determining the ultimate strain of the wellbore instability and destruction according to the claims 1-2, wherein in the step (3), the monitoring of the strain information of the wellbore comprises a plurality of circles of annular pressure relief grooves spaced along the axial direction on the inner wall of the mine wellbore, and the method for monitoring the mine wellbore comprises the following steps: installing an annular force transmission steel ring with the shape matched with the surface of the wall of the shaft cylinder in a monitoring point arranged in the shaft, and installing a plurality of strain sensors on the annular force transmission steel ring and the monitoring point; acquiring a strain signal of the shaft in real time through the strain sensor; the strain signal is led into a data conversion unit outside the mine shaft; and the strain signal is converted by the data conversion unit and transmitted to a data acquisition device outside the mine shaft, so that the strain information of the mine shaft is monitored in real time.
4. The method as claimed in claim 3, wherein the strain sensor is a two-dimensional carbon composite nano metal film flexible strain sensor, and the thickness of the metal film is 550-600 μm.
5. The method for discriminating the ultimate strain of wellbore instability damage according to claims 1-4, characterized in that 4 installation points are arranged on each monitoring point along the up-down, left-right directions, the strain sensor is arranged on each installation point, and the strain sensors are arranged to acquire strain signals of the wellbore along the axial direction, the circumferential direction and the radial direction respectively.
6. The method for judging the limit strain of the wellbore instability damage according to claim 5, wherein the step (2) of establishing a refined three-dimensional geological model comprises a. collecting structural design materials of the wellbore and geological exploration data of a mining area near the wellbore and carrying out information processing: performing three-dimensional and digital processing by using software, and extracting elevation information; clearing repeated points, bridging points and coalescing points in the elevation information file; constructing a digital earth surface model by using the line file;
b. constructing a geological information database; the geological information database comprises a drilling hole coordinate data file, a drilling inclination measuring data file, a sample test data file and a geological code data file; the data files are mutually independent, and the mutual relation is established through the serial numbers and is imported into the three-dimensional software to form a relational database;
c. calling the geological information database, displaying structural design materials of the drill holes and the shaft in a three-dimensional space, and screening out the drill holes contained in the section needing to be drawn currently in a mode of cutting the section along an exploration line or restraining the geological information database; according to the technical condition indexes of ore body mining, and in combination with the ore body circle connection rule, performing geological interpretation on the drill holes on the section, and circling the section ore body to generate a three-dimensional section ore body contour line;
d. carrying out extrapolation processing on the generated three-dimensional profile ore body contour line of each ore body according to the ore body pinch-out tendency and the correlation with the fault; connecting the profile contour lines of all ore bodies according to corresponding conditions, and generating a three-dimensional geological model of each ore body by adopting a triangulation network connection technology; and verifying and correcting the generated three-dimensional geological model.
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| CN114407350A (en) * | 2022-01-11 | 2022-04-29 | 西北工业大学 | Continuous fiber reinforced composite material 3D printing filling path planning method and device |
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| WO2021047328A1 (en) | 2021-03-18 |
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