CN114705549A - Early warning method for instability and mutation of easily-argillized ore rock - Google Patents

Early warning method for instability and mutation of easily-argillized ore rock Download PDF

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CN114705549A
CN114705549A CN202210359147.4A CN202210359147A CN114705549A CN 114705549 A CN114705549 A CN 114705549A CN 202210359147 A CN202210359147 A CN 202210359147A CN 114705549 A CN114705549 A CN 114705549A
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赵康
严雅静
伍俊
赵康奇
杨健
黄奇正
敖文强
聂强
陈佳乐
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Abstract

An early warning method for instability and mutation of easily argillized ore rock comprises the steps of manufacturing ore rock test pieces, respectively carrying out acoustic emission tests on the ore rock test pieces under a uniaxial compression condition, and obtaining displacement, load and acoustic emission parameter values of each ore rock test piece; calculating and analyzing the mutation characteristics of the evolution of the elastic strain energy curve of the easily-argillized ore rock; and constructing an early warning model of destabilization and mutation of the easily-argillized ore rocks of the elastic strain energy strain sequence, wherein the easily-argillized ore rocks are in a stable state when a simultaneous bifurcation set equation delta is greater than 0, the easily-argillized ore rocks are in an unstable state when delta is less than 0, and the easily-argillized ore rocks are in a critical state when delta is equal to 0. The method can comprehensively, quickly and accurately predict the instability mutation damage of the easily argillized ore rocks, and provides a scientific reference basis for early warning and prevention of the instability mutation of the ore rocks mined by mines.

Description

Early warning method for instability and mutation of easily-argillized ore rock
Technical Field
The invention relates to early warning of surrounding rock damage in a mine goaf, in particular to an early warning method for instability and mutation of easily argillized ore rocks.
Background
With the increasing scarcity of mineral resources on the shallow part of the earth surface, the mining gradually goes to the deep part. However, under complex geological conditions encountered in deep mining, such as high heat, high ground pressure, humid environment, high water content and the like, partial deep underground rock is easy to argillization after water absorption, mechanical property deterioration and softening mutation damage, surrounding rock deformation and damage of a goaf are caused, and life and property safety of mining personnel is harmed. The existing early warning method for destabilization of easily-argillized ore rocks mainly comprises three types: the method is suitable for underground roadways with certain depth, but not suitable for non-roadway conditions. The deformation mechanics mechanism early warning is mainly implemented by defining early warning points at physical mechanics parameter mutation positions of indoor test rock samples, such as elastic modulus, stress, strain, Poisson's ratio, deformation modulus and the like, and has the defect of larger individual difference. The numerical simulation analysis is widely used in the early warning of rock materials, mainly aims at simulating and analyzing the stress field, the displacement field and the plastic zone distribution when a rock sample is loaded, so as to determine the early warning characteristics of the rock sample, but is difficult to simulate the complex real geological condition and has certain one-sidedness.
The determination of the mine rock damage precursor characteristics in the mining process is very important for the early warning and prevention of the instability mutation of the mine rock, meanwhile, the damage evolution, the strain change and the instability damage of the mine rock are necessarily accompanied by the energy change, and the energy change runs through the whole process of the mine rock damage and is the quantitative expression of the internal damage. Therefore, the method has certain one-sidedness in analyzing the sudden change destruction characteristics of the ore rock from the energy angle; the damage and the damage of the rock are characterized by multi-angle and random change due to the heterogeneity and the discontinuity in the rock, and the mutation theory can better describe the mutation and the discontinuity of the object change. However, an early warning method for monitoring destabilization and mutation damage of easily-argillized rock by combining mutation theory and energy is rarely reported at present.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for comprehensively, quickly and accurately predicting destabilization mutation damage of easily-argillized rock by establishing the coupling relation between the internal energy of the easily-argillized rock and a strain and cusp mutation model, and provides a scientific reference basis for early warning and prevention of the destabilization mutation of the easily-argillized rock in mining.
In order to achieve the purpose, the invention adopts the following technical scheme:
an early warning method for instability and mutation of easily argillized ore rocks comprises the following steps:
firstly, manufacturing a mineral rock test piece, wherein the mineral rock test piece comprises an easily argillized mineral rock test piece and an unobvious argillized mineral rock test piece;
step two, respectively carrying out acoustic emission tests on the ore rock test piece in the step one under the condition of uniaxial compression, and obtaining the displacement, load and acoustic emission parameter values of each ore rock test piece;
step three, calculating and analyzing the mutation characteristics of the evolution of the elastic strain energy curve of the easily argillized rock;
step four, constructing an early warning model of the easily-argillized ore rock instability and mutation of the elastic strain energy strain sequence, wherein the concrete process is as follows:
the total work of the external force on the rock can be obtained by calculating the area enclosed by a stress-strain curve and a strain axis through calculus, and the total input energy in the rock comprises elastic strain energy and dissipation energy:
U＝Ue+Ud (1)
in the formula, U is the total energy input into the rock by the press, and the unit is J; u shapeeThe elastic strain energy inside the sample is represented by J; u shapedCumulative dissipated energy, in units of J; calculated according to the following formula:
total energy:
Figure BDA0003583123920000021
in the formula: sigmaiThe stress applied to the specimen at the i-th moment is expressed in units of MPa, epsiloniThe strain generated by the sample at the ith moment;
elastic strain energy:
Figure BDA0003583123920000022
cumulative dissipated energy:
Ud＝U-Ue (4)
in the formula: sigmaiThe stress borne by the sample at the moment i is expressed in MPa; v is the sample volume in mm3；EeThe elastic modulus of the test piece is in MPa;
the introduction of the cusp mutation model comprises 3 functional equations respectively:
the standard potential function equation v (x) is:
V(x)＝x4+ux2+zx (5)
in the formula: u and z are control variables, and x is a state variable;
the equilibrium surface equation V' (x) is:
V′(x)＝4x3+2ux+z (6)
the singularity set equation V "(x) is:
V″(x)＝12x2+2u (7)
the equation of the equilibrium surface and the equation of the singular point set need to satisfy and be equal to 0, and the equation of the divergence set obtained by combining the equation (6) and the equation (7) is as follows:
Δ＝8u3+27z2 (8)
when delta is greater than 0, the easily-argillized rock is in a stable state, when delta is less than 0, the easily-argillized rock is in an unstable state, and when delta is 0, the easily-argillized rock is in a critical state.
Further, defining a mutation interval, an early warning point and an early warning interval in the fourth step, verifying by using precursor characteristics of acoustic emission parameters, and assuming elastic strain energy UeThe mapping relation with the strain epsilon is fe(ε), developed by Taylor's formula and retained to 4 terms, can be:
Figure BDA0003583123920000031
in the formula: epsilon0For the value of strain at a particular point, let
Figure BDA0003583123920000032
And when strained ∈0When equal to 0, k0When 0, equation (9) can be converted to:
fe(ε)＝k1ε+k2ε2+k3ε3+k4ε4 (10)
in the formula: k is a radical ofj(j ═ 1,2,3,4) can be determined by least squares approximation, using
Figure BDA0003583123920000033
Converting equation (10) into a standard potential function form of a cusp mutation model, and in a first step:
Figure BDA0003583123920000034
second, the constant terms without x are truncated and x is scaled4The coefficient of (d) is 1, it can be found that:
Figure BDA0003583123920000035
the expression of the derived diversity equation Δ combining equations (5), (8) and (12) is:
Figure BDA0003583123920000036
according to the elastic strain energy sequence f of the easily argillized ore rock under uniaxial compressione(ε) is substituted in formula (10) and subjected to least squares calculation to obtain an approximate analytical expression of the relationship between elastic strain energy and strain:
Figure BDA0003583123920000037
in the formula: f. ofe d(epsilon) is an elastic strain energy sequence of easily argillaceous rocks, fe n(epsilon) is an unobvious argillized ore rock elastic strain energy sequence and is obtained by solving
Figure BDA0003583123920000041
The analytical expressions of the obtained bifurcation set equation delta are substituted as follows:
Figure BDA0003583123920000042
obtaining delta values corresponding to different strains according to the formula (15), and defining a minimum strain interval at the position where the sign of the delta value is changed as a mutation interval I; the strain point corresponding to the maximum value point of the delta is called an early warning point, and the early warning interval II is a strain interval corresponding to a delta interval which is 0.5 percent of the maximum value point of the delta; and further quantitatively judging the mutation state of the easily argillized ore rock by the delta value.
Further, the size of the easily argillized ore rock test piece in the step one is a standard cylinder rock with the height of 100mm and the diameter of 50 mm.
Further, the acoustic emission test in the second step adopts a loading strain test, the loading rate is 0.005mm/s, the loading is stopped when the test piece is damaged, the sampling threshold value of the acoustic emission is 50dB, the gain of the preamplifier is 45dB, and the sampling rate is 3 MSPS.
Further, the abrupt features of the evolution of the elastic strain energy curve of the easily argillized rock in the third step include: the method comprises the steps that an elastic strain energy curve peak value of the easily argillized ore rock is divided into an initial energy dissipation stage and an elastic strain energy accumulation stage; the energy evolution after the elastic strain energy curve peak value of the easily argillized ore rock is divided into a step shape and a cliff shape, and the number of the mutation points of the energy curve is judged.
The invention has the beneficial effects that:
the method analyzes the mutation characteristics of the total energy, elastic strain energy and dissipation energy curves of the easily-argillized ore rocks, establishes the coupling relation between the internal energy of the ore rocks and strain and cusp mutation models, monitors the instability and mutation damage of the easily-argillized ore rocks by combining mutation and energy, comprehensively simulates complex real geological conditions, and rapidly and accurately predicts the instability and mutation damage of the easily-argillized ore rocks; defining a mutation interval, an early warning point and an early warning interval of the easily argillized ore rocks under uniaxial compression according to the size of a divergence set delta, wherein the change position of the positive sign of the divergence set delta value is the mutation interval of the easily argillized ore rocks, the maximum value position of the divergence set delta value is the early warning point, the interval of 0.5 percent delta left and right of the maximum value is the early warning interval, and the delta value is further quantized to judge the mutation state of the easily argillized ore rocks; the reasonability and the accuracy of the early warning model are verified through the precursor characteristics of the acoustic emission parameters; the method can quickly and accurately predict the destabilization mutation damage of the easily argillized ore rocks, and provides a scientific reference basis for early warning and prevention of the destabilization mutation of the ore rocks during mining.
Drawings
FIG. 1 is a stress-strain relationship diagram of an easily argillized ore rock test piece according to an embodiment of the present invention;
FIG. 2a is a stress-energy-strain relationship diagram of a easily argillized rock specimen a according to an embodiment of the present invention;
FIG. 2b is a graph showing a relationship between stress, energy and strain of a sample b of the easily argillized rock ore according to the embodiment of the present invention;
FIG. 2c is a stress-energy-strain relationship diagram of a easily argillized rock specimen c according to an embodiment of the present invention;
FIG. 3 is a schematic diagram showing the relationship between the equation of a cusp mutation model of easily argillized rock according to an embodiment of the present invention;
FIG. 4a is a schematic diagram of an unstable transition early warning of a argillaceous rock test piece a according to an embodiment of the present invention;
FIG. 4b is a schematic diagram of an unstable transition early warning of a argillaceous rock test piece b according to an embodiment of the present invention;
FIG. 4c is a schematic diagram of an unstable transition early warning of a argillaceous rock test piece c according to an embodiment of the present invention;
FIG. 4d is a schematic diagram illustrating an early warning of instability and mutation of an unobvious argillized rock test piece in an embodiment of the present invention;
FIG. 5a is an acoustic emission ringing count rate inspection chart of an easily argillized rock specimen a according to an embodiment of the present invention;
FIG. 5b is a diagram illustrating an acoustic emission ringing count rate test of a non-obvious argillized rock specimen according to an embodiment of the present invention;
FIG. 6a is an acoustic emission energy rate inspection chart of an easily argillized rock specimen a according to an embodiment of the present invention;
FIG. 6b is a graph illustrating the acoustic emission energy rate of a sample of unconscious argillized rock in accordance with an embodiment of the present invention.
Detailed Description
An early warning method for instability and mutation of easily argillized ore rocks comprises the following steps:
the method comprises the following steps of firstly, manufacturing mineral rock test pieces, wherein the mineral rock test pieces comprise easily-argillized mineral rock test pieces a, b and c and unobvious argillized mineral rock test pieces.
The ore rock adopted in the embodiment is taken from a thick tantalum-niobium ore rock which is easy to argillize in Jiangxi Jiangnan, fresh rock samples are taken from the depth of 200m underground, the ore rock samples are taken from 2014 1 month, the ore rock samples which are subjected to water absorption and weathering in the natural environment of the earth surface for 7 years are placed to be made into standard cylindrical ore rock test pieces with the height of 100mm and the diameter of 50mm, and the ore rock test pieces without obvious joints and cracks on the surfaces in the standard test pieces are selected for testing.
Step two, respectively carrying out acoustic emission tests on the ore rock test piece in the step one under the condition of uniaxial compression, and obtaining the displacement, load and acoustic emission parameter values of each ore rock test piece;
as shown in figure 1, the stress peak of the easily-argillized ore rock is of an obvious mutation characteristic under the action of uniaxial compression, and the stress value is greatly reduced under the condition of generating small strain, so that the easily-argillized ore rock test piece is damaged and loses the bearing capacity.
Step three, calculating and analyzing the mutation characteristics of the evolution of the elastic strain energy curve of the easily argillized rock;
U＝Ue+Ud (1)
in the formula, U is the total energy input into the rock by the press, and the unit is J; u shapeeIs the elastic strain energy inside the sample, and the unit is J; u shapedCumulative dissipated energy, in units of J; calculated according to the following formula:
total energy:
Figure BDA0003583123920000051
in the formula: sigmaiThe stress applied to the sample at time i is expressed in units of MPa,. epsiloniThe strain generated by the sample at the ith moment;
elastic strain energy:
Figure BDA0003583123920000061
cumulative dissipated energy:
Ud＝U-Ue (4)
in the formula: sigmaiThe stress borne by the sample at the moment i is expressed in MPa; v is the sample volume in mm3；EeThe elastic modulus of the test piece is in MPa;
as shown in fig. 2a, 2b and 2c, the elastic strain energy curve is divided into three stages before the peak value: initial energy dissipation stage (I), elasticityStrain energy accumulation stage (II) and elastic strain energy dissipation stage (III), the energy evolution behind the elastic strain energy curve peak can be divided into two forms: a "stair-like" and a "cliff-like". Three energy catastrophe points are arranged behind the elastic strain energy curve peak of the easily argillized ore rock test piece in a step shape, and the average increase of strain is 2 multiplied by 10-4The elastic strain energy is respectively reduced by 18.62J, 57.91J and 39.09J, and accounts for 18.34%, 57.05% and 38.51% of the peak elastic strain energy, which indicates that the energy conversion mechanism after the peak stress of the easily argillized rock test piece is unstable and has a sudden change characteristic; the reduction amplitude of the elastic strain energy of the easily-argillized ore rock test piece in the shape of a broken cliff after the peak stress exceeds 50 percent in a small strain range, and the easily-argillized ore rock test piece has an obvious mutation characteristic.
Step four, constructing an easily-argillized ore rock instability and mutation early warning model of the elastic strain energy strain sequence, defining a mutation interval, an early warning point and an early warning interval, and using precursor characteristics of acoustic emission parameters for verification, wherein the specific process is as follows:
rock as a brittle material is easy to be transformed from a stable state to an unstable state under the condition of strong external force disturbance, and further unstable sudden change damage is caused. The mutation theory can be mainly divided into seven mutation models according to the difference of mutation types, wherein the cusp type mutation model, the butterfly type mutation model and the dovetail type mutation model have the widest application range and higher reliability. Therefore, the instability mutation mechanism of the easily-argillized ore rock is analyzed by selecting the cusp type mutation model in the embodiment.
The cusp mutation model comprises 3 function equations which are respectively as follows: standard potential function equations, equilibrium surface equations, and singularity set equations. Wherein the standard potential function equation V (x) is:
V(x)＝x4+ux2+zx (5)
in the formula: u and z are control variables and x is a state variable.
The equilibrium surface equation V' (x) is:
V′(x)＝4x3+2ux+z (6)
the singularity set equation V "(x) is:
V″(x)＝12x2+2u (7)
the equation of the equilibrium surface and the equation of the singular point set need to be equal to 0, and the equation of the divergence set obtained by simultaneous two formulas is as follows:
Δ＝8u3+27z2 (8)
the relationship of each equation is shown in fig. 3, and the equilibrium surface comprises three parts: top, middle and bottom leaves. The middle leaf represents the non-steady state of the system and can be judged by calculating the magnitude of the delta value. When delta is greater than 0, the system is in a stable state; when delta is less than 0, the system is in an unstable state; when Δ is 0, the system is in a critical state.
And (3) selecting the elastic strain energy of the easily argillized ore rock in the test process as a research object, and establishing a sharp point mutation model. Assuming elastic strain energy UeThe mapping relation with the strain epsilon is fe(ε), which is expanded by Taylor's equation and retained to 4 terms, the following formula can be obtained:
Figure BDA0003583123920000071
in the formula: epsilon0For the value of strain at a particular point, let
Figure BDA0003583123920000072
And when strained ∈0When equal to 0, k0When 0, equation (9) can be converted to:
fe(ε)＝k1ε+k2ε2+k3ε3+k4ε4 (10)
in the formula: k is a radical ofj(j ═ 1,2,3,4) can be determined by least squares approximation, using
Figure BDA0003583123920000073
Converting equation (10) into a standard potential function form of a cusp mutation model, and in a first step:
Figure BDA0003583123920000074
second, the constant terms without x are truncated and x is scaled4The coefficient of (d) is 1, it can be found that:
Figure BDA0003583123920000075
the expressions of the joint type (5), the formula (8) and the formula (12) of the derived divergence set equation delta are as follows:
Figure BDA0003583123920000076
according to the elastic strain energy sequence f of the easily argillized ore rock under uniaxial compressione(ε) is substituted in formula (10) and subjected to least squares calculation to obtain an approximate analytical expression of the relationship between elastic strain energy and strain:
Figure BDA0003583123920000077
in the formula: f. ofe d(epsilon) is an elastic strain energy sequence of easily argillaceous rocks, fe n(epsilon) is an unobvious argillized ore rock elastic strain energy sequence and is obtained by solving
Figure BDA0003583123920000081
The analytical expressions of the obtained bifurcation set equation delta are substituted as follows:
Figure BDA0003583123920000082
obtaining delta values corresponding to different strains according to the formula (15), and defining the minimum strain interval at the change position of the delta values in sign as a mutation interval I; the strain point corresponding to the maximum value point of the delta is called an early warning point, and the early warning interval II is a strain interval corresponding to a delta interval which is 0.5 percent of the maximum value point of the delta; the delta value can help to further quantitatively judge the mutation state of the argillaceous rock. As can be seen from fig. 4a, 4b, 4c, and 4d, the energy instability and mutation laws between different argilliferous rock samples are similar, and the mutation sequence is from a mutation interval (i) to an early warning interval (ii). The first sudden change of the easily argillized rock occurs in the area which is transited from the compaction stage to the elastic deformation stage, the original pore closing of the sample at the stage is completed under the action of external load, the elastic strain energy starts to be accumulated, the dissipation energy is reduced, the pseudo instability phenomenon of the rock is caused by the conversion of the internal energy conversion mode, and the false instability sudden change of the rock is formed. The strength of the rock is reduced after the stress peak value is controlled by the releasable elastic strain energy accumulated in the rock, so that the change rule of the elastic strain energy determines the change rule of instability and mutation of the rock, and the mutation interval (I) is generated. And the early warning interval (II) is positioned in front of the stress peak value, and is close to the region where the elastic deformation stage of the easily-argillized ore rock sample is transited to the plastic yield stage. The early warning interval is a strain change range corresponding to the stage that the delta value of the elastic strain energy is converted from a rising peak value to a falling stage, the elastic strain energy accumulation capacity of the easily-argillized ore rock in the interval gradually and slowly falls from the peak value, and the early warning interval indicates that the strength of the rock sample is about to reduce. A large amount of elastic strain energy is accumulated in the rock at the previous stage, so that the sample is in an unstable state, and instability, mutation and damage are easy to occur under small external force disturbance, and the elastic strain energy is released in a large amount in a short time. In addition, the forms of different easily-argillized ore rock early warning intervals have higher consistency, and the early warning model has better universality.
Compared with the non-argillized ore rocks, the strain of the mutation interval and the early warning interval of the easily argillized ore rocks is larger. The reason is that: the easily argillized ore rock is subjected to the effects of water, high temperature, high ground stress, weathering erosion and the like for a long time, a large amount of secondary products are generated inside the easily argillized ore rock, the brittleness degree of the rock is weakened by the secondary products, the ductility of the rock when the rock is loaded is enhanced, and the rock can generate more strain when the rock is loaded and is close to damage. But simultaneously, the secondary products, the micro-holes and the pores greatly reduce the strength of the rock, so that the rock instability and mutation behavior with suddenly reduced strength is generated under the condition of lower stress.
As can be seen from fig. 5a and 5b, and fig. 6a and 6b, the abrupt change interval, the early warning point, and the early warning interval obtained according to the abrupt change model of the easy-argillization rock peak have a high degree of agreement with the precursor features of the acoustic emission ringing count rate and the acoustic emission cumulative energy rate. Therefore, the sharp point mutation model can well warn instability and mutation damage of easily-argillized ore rocks under uniaxial compression, mutation intervals, prewarning points and prewarning intervals of non-argillized ore rock test pieces are inconsistent with precursor characteristics of acoustic emission ringing counting and acoustic emission accumulated energy rate, and certain hysteresis exists. The mutation interval, the early warning interval and the early warning points of the easily-argillized ore rock test piece are shown in table 1, wherein A-7, A-10 and A-11 are easily-argillized rock samples, and CB-2 is an unobvious argillized rock sample.
TABLE 1 examination of Acoustic emission parameters
Figure BDA0003583123920000091
According to the method, the instability cusp mutation model of the easily-argillized rock is constructed by combining strain and elastic strain energy, the instability abrupt change damage of the easily-argillized rock is quantified, the abrupt change damage of the easily-argillized rock can be comprehensively, quickly and accurately predicted, and a scientific reference basis is provided for the surrounding rock instability early warning and prevention work of mining. The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the invention.

Claims (5)

1. The early warning method for instability and mutation of easily argillized ore rocks is characterized by comprising the following steps of:
firstly, manufacturing a mineral rock test piece, wherein the mineral rock test piece comprises an easily argillized mineral rock test piece and an unobvious argillized mineral rock test piece;
step two, respectively carrying out acoustic emission tests on the ore rock test piece in the step one under the condition of uniaxial compression, and obtaining the displacement, load and acoustic emission parameter values of each ore rock test piece;
step three, calculating and analyzing the mutation characteristics of the evolution of the elastic strain energy curve of the easily argillized rock;
step four, constructing an easily-argillized ore rock instability and mutation early warning model of the elastic strain energy strain sequence, wherein the concrete process is as follows:
the total work of the external force on the rock can be obtained by calculating the area enclosed by a stress-strain curve and a strain axis through calculus, and the total input energy in the rock comprises elastic strain energy and dissipation energy:
U＝Ue+Ud (1)
in the formula, U is the total energy input into the rock by the press, and the unit is J; u shapeeIs the elastic strain energy inside the sample, and the unit is J; u shapedCumulative dissipated energy, in units of J; calculated according to the following formula:
total energy:
Figure FDA0003583123910000011
in the formula: sigmaiThe stress applied to the sample at time i is expressed in units of MPa,. epsiloniThe strain generated by the sample at the ith moment; elastic strain energy:
Figure FDA0003583123910000012
cumulative dissipated energy:
Ud＝U-Ue (4)
in the formula: sigmaiThe stress borne by the sample at the moment i is expressed in MPa; v is the sample volume in mm3；EeThe elastic modulus of the test piece is in MPa;
the introduction of the cusp mutation model comprises 3 functional equations respectively:
the standard potential function equation V (x) is:
V(x)＝x4+ux2+zx (5)
in the formula: u and z are control variables, and x is a state variable;
the equilibrium surface equation V' (x) is:
V′(x)＝4x3+2ux+z (6)
the singularity set equation V "(x) is:
V″(x)＝12x2+2u (7)
the equation of the equilibrium surface and the equation of the singular point set need to satisfy and be equal to 0, and the equation of the divergence set obtained by combining the equation (6) and the equation (7) is as follows:
Δ＝8u3+27z2 (8)
when delta is greater than 0, the easily-argillized rock is in a stable state, when delta is less than 0, the easily-argillized rock is in an unstable state, and when delta is 0, the easily-argillized rock is in a critical state.
2. The method for early warning of destabilization and mutation of easily argillized ore rocks according to claim 1, wherein a mutation interval, an early warning point and an early warning interval are defined in the fourth step, and precursor characteristics of acoustic emission parameters are used for verification, and the specific process is as follows: assuming elastic strain energy UeThe mapping relation with the strain epsilon is fe(ε), developed by Taylor's formula and retained to 4 terms, can be:
Figure FDA0003583123910000021
in the formula: epsilon0For the value of strain at a particular point, let
Figure FDA0003583123910000022
And when strained ∈0When equal to 0, k0When 0, equation (9) can be converted to:
fe(ε)＝k1ε+k2ε2+k3ε3+k4ε4 (10)
in the formula: k is a radical ofj(j ═ 1,2,3,4) can be determined by least squares approximation, using
Figure FDA0003583123910000023
Converting equation (10) into a standard potential function form of a cusp mutation model, and in a first step:
Figure FDA0003583123910000024
second, the constant terms without x are truncated and x is scaled4The coefficient of (d) is 1, it can be found that:
Figure FDA0003583123910000025
the expression of the derived diversity equation Δ combining equations (5), (8) and (12) is:
Figure FDA0003583123910000026
according to the elastic strain energy sequence f of the easily argillized ore rock under uniaxial compressione(ε) is substituted in formula (10) and subjected to least squares calculation to obtain an approximate analytical expression of the relationship between elastic strain energy and strain:
Figure FDA0003583123910000031
in the formula: f. ofe d(epsilon) is an elastic strain energy sequence of easily argillaceous rocks, fe n(epsilon) is an unobvious argillized ore rock elastic strain energy sequence and is obtained by solving
Figure FDA0003583123910000032
The analytical expressions of the derived bifurcation set equation Δ are substituted as follows:
Figure FDA0003583123910000033
obtaining delta values corresponding to different strains according to the formula (15), and defining the minimum strain interval at the change position of the delta values in sign as a mutation interval I; the strain point corresponding to the maximum value point of the delta is called an early warning point, and the early warning interval II is a strain interval corresponding to a delta interval which is 0.5 percent of the maximum value point of the delta; and further quantitatively judging the mutation state of the easily argillized ore rock by the delta value.
3. The method for early warning of instability and mutation of easily-argillized rock ore according to claim 1 or 2, wherein the test piece of the easily-argillized rock ore in the step one is a standard cylindrical rock with the height of 100mm and the diameter of 50 mm.
4. The early warning method for instability and mutation of easily argillized ore rock according to claim 1 or 2, wherein the acoustic emission test in the second step is a loading strain test, the loading rate is 0.005mm/s, the test piece stops loading when damaged, the sampling threshold value of the acoustic emission is 50dB, the gain of the preamplifier is 45dB, and the sampling rate is 3 MSPS.
5. The method for early warning of destabilization mutation of easily-argillized rock ore according to claim 1 or 2, wherein the step three of analyzing the mutation characteristics of the evolution of the elastic strain energy curve of the easily-argillized rock ore comprises the following steps: the energy evolution after the elastic strain energy curve peak of the easily argillized ore rock is divided into a step shape and a cliff shape, and the number of the mutation points of the energy curve is judged.
CN202210359147.4A 2022-04-06 2022-04-06 Early warning method for instability and mutation of easily-argillized ore rock Pending CN114705549A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117250259A (en) * 2023-11-08 2023-12-19 青岛理工大学 Rock mass instability mutation early warning method, system and electronic equipment
CN117589890A (en) * 2024-01-19 2024-02-23 四川省自然资源勘察设计集团有限公司 Rock collapse early warning method and system based on acoustic emission characteristics

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117250259A (en) * 2023-11-08 2023-12-19 青岛理工大学 Rock mass instability mutation early warning method, system and electronic equipment
CN117250259B (en) * 2023-11-08 2024-01-30 青岛理工大学 Rock mass instability mutation early warning method, system and electronic equipment
CN117589890A (en) * 2024-01-19 2024-02-23 四川省自然资源勘察设计集团有限公司 Rock collapse early warning method and system based on acoustic emission characteristics
CN117589890B (en) * 2024-01-19 2024-03-26 四川省自然资源勘察设计集团有限公司 Rock collapse early warning method and system based on acoustic emission characteristics

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