Method for predicting rock permeability during elastic-viscoelastic-viscoplastic deformation stages

Abstract

The present application provides a kind of elastic-viscoelastic-viscoplastic deformation stage rock permeability prediction method, belong to rock permeability prediction technical field;In order to effectively predict the permeability evolution trend of rock in different deformation stages, overcome the deficiencies of prior art, provide a kind of elastic-viscoelastic-viscoplastic deformation stage rock permeability prediction method, the technical scheme for using is as follows: rock triaxial compression experiment is carried out, and the triaxial compressive strength data of rock under different confining pressure level conditions is obtained;Creep stress level is set, rock sample creep-seepage experiment is carried out, and the axial deformation data of rock sample, the gas pressure data of sample gas inlet end and gas outlet end are obtained;The axial load of rock sample is unloaded to hydrostatic pressure state, and the seepage experiment in pressure relief deformation recovery stage is carried out while confining pressure remains unchanged;The present application is applied to the calculation and prediction of rock permeability.

Description

TECHNICAL FIELD

[0001] The application provides a method for predicting rock permeability in elastic-viscoelastic-viscoplastic deformation stages, and belongs to the technical field of rock permeability prediction. BACKGROUND

[0002] With the development of geotechnical engineering and mining engineering in recent years, the challenges faced by engineering are gradually increasing, especially the increase in construction depth, which makes the surrounding environment of engineering structure tend to be complex, that is, deep environment. Existing research shows that rock and other loaded media under deep environment will be affected by high ground stress and high permeation pressure, changing its mechanical properties and seepage characteristics; taking deep rock roadway as an example, the mechanical properties and permeability of the rock around the roadway are crucial to the stability of the roadway. Due to the existence of deep environment, the deformation of rock caused by high ground stress and the water leakage accident of roadway induced by high permeation pressure gradually increase, which seriously affects the stability of the roadway; in addition, the deformation behavior of rock will affect the permeability, and the rock will produce elastic deformation, viscoelastic deformation and viscoplastic deformation under the influence of high ground stress during a long service process, which changes the permeability of rock and also affects the stability of the roadway structure, so predicting the permeability of rock in different deformation stages is of great significance to the safe operation of the roadway.

[0003] At present, there are corresponding test methods for rock and coal deformation and permeability in geotechnical engineering and mining engineering, a lot of work has been done on instantaneous elastic deformation, creep deformation and permeability determination, although the work of permeability test under the influence of creep deformation has been carried out, but the evolution trend of permeability in elastic, viscoelastic and viscoplastic deformation stages is not analyzed in detail, and there is a lack of effective prediction method at present.

[0004] Carrying out the prediction of rock permeability in elastic, viscoelastic and viscoplastic deformation stages can well reflect the deformation and permeability evolution of the surrounding rock of the roadway during the service process, and provide important technical support for exploring the actual mechanical response and permeability of the surrounding rock of the roadway in deep geotechnical engineering, and the prediction method of rock permeability in elastic, viscoelastic and viscoplastic deformation stages has a significant effect on guiding the safe operation and production of deep engineering. SUMMARY

[0005] In order to effectively predict the evolution trend of rock permeability in different deformation stages, overcome the shortcomings of the prior art, and provide a method for predicting rock permeability in elastic-viscoelastic-viscoplastic deformation stages.

[0006] In order to solve the above technical problems, the technical scheme adopted by the application is as follows: the method for predicting rock permeability in elastic-viscoelastic-viscoplastic deformation stages comprises the following permeability prediction steps:

[0007] Step S1, perform rock triaxial compression experiment to obtain triaxial compressive strength data of the rock under different confining pressure levels;

[0008] Step S2, set the creep stress level with reference to the triaxial compressive strength data, perform rock sample creep-seepage experiment, and obtain axial deformation data of the rock sample, gas pressure data of the sample gas inlet end and gas outlet end;

[0009] Step S3, after the rock sample creep-seepage experiment reaches the preset period, unload the axial load of the rock sample to hydrostatic pressure state, keep the confining pressure unchanged, perform seepage experiment in the pressure relief deformation recovery stage, and monitor the axial and lateral creep deformation data of the rock sample in the pressure relief deformation recovery stage, and the gas pressure data of the rock sample gas inlet end and gas outlet end;

[0010] Step S4, draw the creep-time curve and the deformation recovery curve according to the deformation data of the rock sample in the creep-seepage experiment stage and the pressure relief deformation recovery stage;

[0011] Step S5, combine the gas pressure attenuation data of the rock sample gas inlet end and gas outlet end, and use the permeability transient solution method to calculate the permeability of the rock sample in the creep deformation stage and the deformation recovery stage;

[0012] Step S6, obtain the permeability evolution empirical formula of the rock sample under the influence of creep deformation according to the creep deformation and permeability experimental data of the rock sample;

[0013] Step S7, based on the strain superposition principle of the Westergaard creep model, decompose the creep deformation increment Δε creep in the permeability evolution empirical formula into the superposition of the elastic deformation increment Δε E , the viscoelastic deformation increment Δε VE , and the viscoplastic deformation increment Δε VP , the values of each deformation increment are obtained from the curve drawn in step S4, and further obtain the permeability prediction formula of the rock sample in different deformation stages;

[0014] Step S8, according to the permeability evolution law in the pressure relief deformation recovery stage, calculate the permeability dynamic change data of the rock sample in the elastic deformation recovery stage, the viscoelastic deformation recovery stage, and the viscoplastic deformation recovery stage, and determine the weight coefficient a1 before the elastic deformation term, the weight coefficient a2 before the viscoelastic deformation term, and the weight coefficient a3 before the viscoplastic deformation term in the permeability evolution empirical formula;

[0015] Step S9, based on the weight coefficient values of each deformation term determined in step S8, a rock permeability calculation formula for distinguishing elastic, viscoelastic and viscoplastic deformation stages is constructed, and the permeability of the rock to be monitored in the elastic, viscoelastic and viscoplastic deformation stages is predicted according to the constructed rock permeability calculation formula.

[0016] The specific method of the rock triaxial compression experiment in the step S1 is as follows:

[0017] Step S11, selecting and preparing a rock sample:

[0018] Select a rock mass from a geotechnical engineering site, use a coring device to core the rock mass, and process it into a cylindrical rock sample with a diameter of 50mm x height of 100mm;

[0019] Step S12, installing the rock sample:

[0020] After evenly applying vaseline to both ends of the rock sample, wrap it with a thermoplastic tube to isolate the sample from the liquid outside the thermoplastic tube,

[0021] Place the rock sample wrapped with the thermoplastic tube in the center of the triaxial loading chamber base boss and fix it, install the axial LVDT and circumferential deformation sensors at the same time, make the sensors parallel to the surface of the rock sample, connect the wires of the sensors, assemble the triaxial loading chamber, and check the airtightness of the loading chamber;

[0022] Step S13, determining the triaxial strength parameters of the rock sample:

[0023] Use the MTS rock mechanics test system to perform triaxial compression tests on the rock sample under different confining pressures, load the confining pressure in pressure control mode, keep it constant after reaching the set confining pressure value, load the axial displacement in displacement control mode until the rock sample fails, and end the test;

[0024] According to the experiment, the basic mechanical parameters of the rock sample are obtained, including: elastic modulus, Poisson's ratio, internal friction angle, cohesion, and triaxial compression strength.

[0025] The specific method of the rock sample creep-seepage experiment in step S2 is as follows:

[0026] Step S21, use the MTS rock mechanics test system to perform creep-seepage experiments on the rock sample under different creep stress levels, load the axial pressure and confining pressure in pressure control mode, and keep it constant after reaching the set deviatoric stress state;

[0027] The gas pressure of the rock sample at the inlet and outlet is set to 2 MPa, respectively, for 12 hours, so that the gas inside the rock sample is in a saturated state. After saturation, the gas pressure at the outlet of the rock sample is set to 1 MPa, so that the rock sample is subjected to seepage under a gas seepage pressure difference of 1 MPa.

[0028] In step S22, the axial and hoop creep deformation data of the rock sample are monitored using the axial LVDT and hoop deformation sensor, and the decay of the gas pressure difference between the two ends of the rock sample is recorded synchronously.

[0029] The specific method for calculating the permeability in step S5 is as follows:

[0030] It is assumed that the pressure difference between the upper and lower ends of the rock sample is P0 at the beginning of the experiment, and the fluid flows from top to bottom. During this process, the pressure at the upper end of the rock sample gradually decreases, and the pressure at the lower end gradually increases. When the flow time is t, the pressure difference between the upper and lower ends decreases to P(t). At this time, the change of the pressure difference between the upper and lower ends of the rock sample with time is described by a negative exponential function, and the expression is:

[0031] P(t)=P0·e -at ;

[0032] Wherein:

[0033]

[0034] The calculation formula of the transient method permeability experimental data k is obtained by combining the above expressions:

[0035]

[0036] In the formula, β is the compressibility of the gas; V is the volume of the gas chamber; P0 and P(t) are the permeation pressure differences at the beginning and end of the permeability measurement, respectively, and satisfy P(t)=P u -P d ; t is the duration of the permeability measurement; A and L are the cross-sectional area and height of the rock sample, respectively.

[0037] The empirical formula of the permeability evolution under the influence of creep deformation obtained in step S6 is:

[0038] k creep =k0(1-aΔε creep ) b ;

[0039] In the formula, k creep is the permeability under the influence of creep deformation; k0 is the initial permeability of the rock sample; ΔE creep is the creep deformation increment of the rock sample; a and b are undetermined coefficients.

[0040] The permeability prediction formula of the rock sample obtained in the step S7 at different deformation stages is specifically:

[0041]

[0042] In the formula, a1, a2 and a3 are weight coefficients of respective deformation terms, and reflect the influence degree of different deformation stages on the permeability evolution.

[0043] The present application has the beneficial effects that the present application provides a rock permeability prediction method in the stages of elastic, viscoelastic and viscoplastic deformation, considers the influence degree of different deformation stages on the rock permeability, can well describe the permeability evolution characteristics of the rock in different deformation states, and has applicability to the permeability prediction in different deformation stages; the present application identifies the rock permeability calculation formula in the stages of elastic, viscoelastic and viscoplastic deformation by combining the deformation and permeability monitoring results of two kinds of experimental results through the creep-seepage experiment and the seepage experiment in the unloading deformation recovery stage, and the results show that the permeability prediction method can well describe the permeability evolution trend in different deformation stages, and verifies the effectiveness of the prediction method. BRIEF DESCRIPTION OF DRAWINGS

[0044] The present application will be further described below in combination with the drawings:

[0045] Figure 1 The present application is a step flow chart for rock permeability prediction;

[0046] Figure 2 The present application is a curve schematic diagram of creep and unloading deformation recovery in the embodiment;

[0047] Figure 3 The present application is an evolution data effect diagram of permeability in the stages of creep and unloading deformation recovery in the embodiment. DETAILED DESCRIPTION

[0048] As Figure 1As shown, the present application provides a rock permeability prediction scheme in the elastic-viscoelastic-viscoplastic deformation stage, and the main prediction steps include: carrying out rock conventional triaxial compression test to obtain triaxial compressive strength of rock under different confining pressure conditions; referring to the conventional triaxial compressive strength data, setting the creep stress level, carrying out rock sample creep-seepage experiment and seepage experiment in the unloading deformation recovery stage; according to the sample deformation data and the gas pressure data at both ends of the sample, a creep-time curve is drawn, and the permeability of the sample in the creep stage and the deformation recovery stage is calculated by using the permeability transient solution method; combining the creep deformation and the permeability experimental data, the permeability evolution empirical formula under the influence of creep deformation is obtained; according to the strain superposition principle of the Westergaard model, the creep deformation of the permeability evolution empirical formula is decomposed into the superposition of elastic deformation, viscoelastic deformation and viscoplastic deformation, forming the permeability prediction formula in different deformation stages, and the weight coefficients in front of each deformation term need to be determined combined with the permeability evolution data in different deformation recovery stages, and then a method for predicting the permeability evolution law of rock in different deformation stages is established.

[0049] In the embodiment of the present application, a rock permeability prediction method in the elastic-viscoelastic-viscoplastic deformation stage is specifically provided, which comprises the following prediction steps:

[0050] Step S1, carrying out rock conventional triaxial compression test to obtain triaxial compressive strength of rock under different confining pressure conditions; wherein the specific test steps of rock triaxial compression test are as follows:

[0051] Step S11, rock sample selection and preparation. Select rock blocks in deep geotechnical engineering site, select large-size rock blocks with good integrity and no obvious cracks, use coring equipment to core the rock blocks, process into standard cylindrical samples with a specification of diameter 50mm*height 100mm, control the diameter and end face flatness of the rock sample within the error range; select the sample with close wave velocity value, i.e. small difference, as the experimental sample through wave velocity measurement of the rock sample;

[0052] Step S12, rock sample installation. Apply vaseline evenly on both ends of the rock sample to reduce the friction between the loading end of the experimental device and the end face of the sample, and avoid end effect; wrap the rock sample with a thermoplastic tube to isolate the sample from the liquid outside the thermoplastic tube, and avoid contamination of the confining pressure oil by the sample and rock debris during the test; place the rock sample wrapped with the thermoplastic tube on the center of the boss of the triaxial loading chamber base and fix it, and then start installing the axial LVDT and the ring deformation sensor to make the sensors parallel to the surface of the rock sample; after ensuring that the wires of each sensor are connected correctly, assemble other parts of the triaxial loading chamber, and check the air tightness after assembly.

[0053] Step S13, rock sample triaxial strength and other basic mechanical parameter determination. After the rock sample is installed, the MTS rock mechanics test system is used to carry out the conventional triaxial compression test of the rock sample under different confining pressures; the confining pressure is loaded in the pressure control mode, and is kept constant after reaching the set confining pressure value; the axial direction is loaded in the displacement control mode until the rock sample is destroyed, and the test is ended; the basic mechanical parameters of the rock sample are obtained, including the elastic modulus, Poisson's ratio, internal friction angle, cohesion, triaxial compression strength and the like.

[0054] Step S2, the conventional triaxial compression strength data is used as a reference to set the creep stress level, the rock sample creep-seepage experiment is carried out, and the axial deformation data of the rock sample, the gas pressure data of the gas inlet end and the gas outlet end of the sample are obtained; the specific steps of the rock sample creep-seepage experiment are as follows:

[0055] Step S21, rock sample creep-seepage experiment. The preparation and installation of the rock sample used in the experiment are as described in steps S11 and S12; the MTS rock mechanics test system is used to carry out the creep-seepage experiment under different creep stress levels, and the axial pressure and the confining pressure are loaded in the pressure control mode and kept constant after reaching the set deviatoric stress state; the gas pressure of the gas inlet end and the gas outlet end of the sample is set to 2 MPa respectively and kept for 12 hours, so that the internal gas of the rock sample is in a saturated state; after saturation, the gas pressure of the gas outlet end of the rock sample is set to 1 MPa, so that the sample seeps under the gas seepage pressure difference of 1 MPa;

[0056] Step S22, sample deformation and gas pressure data determination. The axial and circumferential creep deformation data of the rock sample are monitored by using the axial LVDT and circumferential deformation sensor, and the decay of the gas pressure difference of the two ends of the sample is recorded synchronously.

[0057] Step S3, after the rock sample creep-seepage experiment reaches a certain period of time, the axial load of the rock sample is unloaded to the hydrostatic pressure state, the confining pressure is kept unchanged, and the seepage experiment in the pressure relief deformation recovery stage is further carried out, and the deformation in the pressure relief deformation recovery stage, the gas pressure data of the gas inlet end and the gas outlet end of the sample are monitored;

[0058] The axial and lateral creep deformation and gas pressure difference decay data in the pressure relief deformation recovery stage are monitored as described in step S22.

[0059] Step S4, according to the deformation data in the creep-seepage experiment stage and the pressure relief deformation recovery stage of the rock sample, the creep-time curve and the deformation recovery curve are drawn as shown in Figure 2 .

[0060] Step S5, combined with the gas pressure decay data of the two ends of the rock sample, the permeability transient solution method is used to calculate the permeability of the rock sample in the creep deformation stage and the deformation recovery stage.

[0061] The permeability transient method solving method is shown in formulas (1) to (3), and the permeability evolution trend in the creep deformation stage and the pressure relief deformation recovery stage is shown in Figure 3 Compared with the steady-state method, the transient method is more suitable for permeability determination of low-permeability rocks. The upper and lower ends of the sample produce a significant pressure difference P0, and the fluid flows from top to bottom. In this process, the upper end pressure gradually decreases, while the lower end pressure gradually increases. When the flow time is t, the upper and lower end pressure difference decreases to P(t). The change of the upper and lower end pressure difference with time can be described by a negative exponential function:

[0062] P(t)=P0·e -at (1);

[0063] wherein:

[0064]

[0065] By combining formula (1) and formula (2), the calculation formula of the permeability experimental data k of the transient method is as follows:

[0066]

[0067] In the formula, β is the compressibility of the gas; V is the volume of the gas chamber; P0 and P(t) are the permeation pressure differences when the permeability is measured initially and terminated, respectively, P(t)=P u -P d ; t is the time length for measuring the permeability; A and L are the cross-sectional area and height of the rock sample, respectively.

[0068] Step S6, according to the creep deformation and permeability experimental data of the rock sample (see Figure 2 and Figure 3 ), the permeability evolution empirical formula under the influence of creep deformation is obtained, and the expression is shown in formula (4):

[0069] k creep =k0(1-aΔε creep ) b (4);

[0070] In the formula, k creep is the permeability under the influence of creep deformation; k0 is the initial permeability of the rock sample; Δε creep is the creep deformation increment of the rock sample; a and b are to-be-determined coefficients.

[0071] Step S7, based on the strain superposition principle of the Westergaard creep model, the creep deformation increment Δε creep in the permeability evolution empirical formula is decomposed into an elastic deformation increment Δε E , a viscoelastic deformation increment Δε VE and a viscoplastic deformation increment ΔεVP The values ​​of each deformation increment are obtained from the data described in S4, and the permeability prediction formula for different deformation stages is shown in equation (5):

[0072]

[0073] In the formula, a1, a2 and a3 are the weighting coefficients of each deformation term, which reflect the degree of influence of different deformation stages on the evolution of permeability.

[0074] It should be noted that during the creep deformation stage, the pores and fissures inside the rock sample are gradually compressed, which in turn causes the permeability of the sample to gradually decrease, i.e., the permeability shows a gradual downward trend. During the pressure relief deformation recovery stage, the axial load is unloaded, which causes the compression deformation of the rock sample to decrease instantaneously. The seepage channels inside the sample expand synchronously, resulting in an instantaneous increase in permeability. As the unloading time gradually extends, the viscoelastic deformation caused by pressure relief is fully recovered, and the compression of the seepage channels caused by it will also gradually recover, and the permeability data will gradually increase. After the amount of deformation recovered by pressure relief remains constant for a long period of time, it indicates that the deformation recovery is complete. The deformation that has not yet recovered relative to the initial uncompressed state is called viscoplastic deformation, and the decrease in permeability compared to the initial permeability is caused by viscoplastic deformation.

[0075] Step S8, Combining Figure 3 The evolution law of permeability during the decompression deformation recovery stage was studied. The dynamic change data of permeability during the instantaneous recovery of elastic deformation, delayed recovery of viscoelastic deformation, and failure to recover viscoplastic deformation stage were calculated. The weight coefficients a1, a2, and a3 before the elastic deformation, viscoelastic deformation, and viscoplastic deformation terms in the empirical formula for permeability evolution were determined.

[0076] Step S9: Based on the weight coefficient values ​​of each deformation term determined in step S8, construct a rock permeability calculation formula that can distinguish between elastic, viscoelastic and viscoplastic deformation stages. Based on the constructed rock permeability calculation formula, predict the permeability of the rock to be monitored in the elastic, viscoelastic and viscoplastic deformation stages respectively.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for predicting the permeability of rocks in the elastic-viscoelastic-viscoplastic deformation regime, characterized in that: The permeability prediction step comprises the following steps: Step S1, perform rock triaxial compression experiment to obtain triaxial compressive strength data of rock under different confining pressure conditions; Step S2, set the creep stress level based on the triaxial compressive strength data, perform rock sample creep-seepage experiment, and obtain axial deformation data of the rock sample, gas pressure data of the sample gas inlet end and gas outlet end; Step S3, after the rock sample creep-seepage experiment reaches the preset period, unload the axial load of the rock sample to hydrostatic pressure state, keep the confining pressure unchanged, perform seepage experiment in the pressure relief deformation recovery stage, and monitor the axial and lateral creep deformation data of the rock sample in the pressure relief deformation recovery stage, and the gas pressure data of the rock sample gas inlet end and gas outlet end; Step S4, draw the creep-time curve and deformation recovery curve according to the deformation data of the rock sample in the creep-seepage experiment stage and the pressure relief deformation recovery stage; Step S5, combine the gas pressure attenuation data of the rock sample gas inlet end and gas outlet end, and use the permeability transient solution method to calculate the permeability of the rock sample in the creep deformation stage and the deformation recovery stage respectively; Step S6, according to the creep deformation and permeability experimental data of the rock sample, obtain the permeability evolution empirical formula of the rock sample under the influence of creep deformation; Step S7, based on the strain superposition principle of the west creep model, the creep deformation increment Δε creep of the permeability evolution empirical formula is decomposed into the superposition of elastic deformation increment Δε E , viscoelastic deformation increment Δε VE , and viscoplastic deformation increment Δε VP The values of each deformation increment are obtained from the curve drawn in step S4, and the permeability prediction formula of the rock sample at different deformation stages is further obtained. Step S8, according to the permeability evolution law in the pressure relief deformation recovery stage, calculate the permeability dynamic change data of the rock sample in the elastic deformation stage, the viscoelastic deformation stage and the viscoplastic deformation stage respectively, and determine the weight coefficients a1, a2 and a3 in front of the elastic deformation term, the viscoelastic deformation term and the viscoplastic deformation term in the permeability evolution empirical formula respectively; Step S9, based on the weight coefficient values of each deformation term determined in step S8, construct a rock permeability calculation formula for distinguishing the elastic, viscoelastic and viscoplastic deformation stages, and predict the permeability of the rock in the elastic, viscoelastic and viscoplastic deformation stages according to the constructed rock permeability calculation formula.

2. The method for predicting the permeability of rocks in the elastic-visco-elastic- viscoplastic deformation regime according to claim 1, characterized in that: The specific method for performing rock triaxial compression experiment in step S1 is as follows: Step S11, select and prepare rock sample: Select rock mass from geotechnical engineering site, use coring equipment to core the rock mass, and process into cylindrical rock sample with specifications of 50mm in diameter and 100mm in height; Step S12, install rock sample: After evenly applying vaseline on both ends of the rock sample, wrap it with thermoplastic tube to isolate the sample from the liquid outside the thermoplastic tube, Place the rock sample wrapped with thermoplastic tube in the center of the three-axis loading chamber base boss and fix it, install axial LVDT and ring deformation sensor at the same time, make the sensor parallel to the surface of the rock sample, connect the wires of each sensor, assemble the three-axis loading chamber, and check the air tightness of the loading chamber; Step S13, measure the triaxial strength parameters of the rock sample: The triaxial compression test is carried out on the rock sample under different confining pressures by using the MTS rock mechanics test system, the confining pressure is loaded by using the pressure control mode, the constant confining pressure is kept after reaching the set confining pressure value, the axial direction is loaded by using the displacement control mode, until the rock sample is damaged, and the test is ended; According to the experiment, the basic mechanical parameters of the rock sample are obtained, including the elastic modulus, the Poisson's ratio, the internal friction angle, the cohesion, and the triaxial compression strength.

3. The method for predicting the permeability of rocks in the elastic-visco-elastic- viscoplastic deformation regime according to claim 2, characterized in that: The specific method for carrying out the rock sample creep-seepage experiment in the step S2 is as follows: In step S21, the creep-seepage experiment is carried out on the rock sample under different creep stress levels by using the MTS rock mechanics test system, the axial pressure and the confining pressure are loaded by using the pressure control mode, and the constant bias stress state is kept after reaching the set bias stress state; The gas pressure of the gas inlet end and the gas outlet end of the rock sample is set to 2 MPa respectively, and is kept for 12 hours, so that the internal gas of the rock sample is in a saturated state, after saturation, the gas pressure of the gas outlet end of the rock sample is set to 1 MPa, so that the rock sample carries out seepage under the gas seepage pressure difference of 1 MPa; In step S22, the axial and ring creep deformation data of the rock sample are monitored by using the axial LVDT and the ring deformation sensor, and the attenuation of the gas pressure difference between the two ends of the rock sample is recorded synchronously.

4. The method for predicting the permeability of rocks in the elastic-visco-elastic- viscoplastic deformation regime according to claim 3, characterized in that: The specific method for calculating the permeability by using the permeability transient solution method in the step S5 is as follows: The pressure difference between the upper and lower ends of the rock sample is set as P0 at the beginning of the experiment, and the fluid flows from top to bottom. During this process, the pressure at the upper end of the rock sample gradually decreases, and the pressure at the lower end gradually increases. When the flow time is t, the pressure difference between the upper and lower ends decreases to P(t). At this time, the change of the pressure difference between the upper and lower ends of the rock sample with time is described by a negative exponential function, and the expression is: P(t) = P0·e -at ; Wherein: The calculation formula of the transient method permeability experimental data k is obtained by comprehensively using the above expression as follows: where β is the compressibility of the gas; V is the volume of the gas chamber; P0 and P(t) are the pressure differences across the permeameter at the beginning and end of the permeability measurement, respectively, such that P(t) = P0 - P u -P d ; t is the length of the permeability measurement; and A and L are the cross-sectional area and height of the rock sample, respectively.

5. The method for predicting the permeability of rocks in the elastic-visco-elastic- viscoplastic deformation regime according to claim 4, characterized in that: The specific formula of the permeability evolution under the influence of the creep deformation obtained in the step S6 is as follows: k creep = k0(1 - a Δε creep ) b ; wherein: k creep is the permeability under the influence of creep deformation; k0is the initial permeability of the rock sample; Δε creep is the increment of creep deformation of the rock sample; a and b are undetermined coefficients.

6. The method for predicting the permeability of rocks in the elastic-visco-elastic- viscoplastic deformation regime according to claim 5, characterized in that: The specific formula of the permeability prediction of the rock sample in different deformation stages obtained in the step S7 is as follows: In the formula, a1, a2 and a3 are weight coefficients of each deformation term, which represent the influence degree of different deformation stages on the permeability evolution.

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