Method for determining water saturation in loading failure process of rock

Abstract

The invention discloses a method for determining water saturation in a rock loaded failure process. The method comprises the following steps: fitting to obtain a function relation between any two of three parameters of strain, acoustic emission energy and resistivity of a rock test piece and initial water saturation; aiming at a rock sample with unknown water saturation, acquiring strain, acoustic emission energy and resistivity data in a multivariate information collaborative monitoring experiment process, and substituting the data into the function relational expression to invert to obtain the initial water saturation of the rock; and substituting the initial water saturation and the resistivity measured at any moment in the multivariate information collaborative monitoring experiment process into a rock water saturation inversion formula to obtain the water saturation at any moment in the rock loaded damage process. By adopting the technical scheme of the embodiment of the invention, the water saturation in the loaded rock damage process can be quickly and quantitatively inverted by using the deformation, acoustic emission energy and resistivity data monitored in a laboratory.

Description

Technical Field

[0001] The invention belongs to the technical field of rock physics, and in particular relates to a method for determining water saturation in a rock load failure process. Background Art

[0002] The destruction of water-blocking surrounding rock and the migration of groundwater due to mining will be accompanied by changes in multi-physical field information such as surrounding rock deformation, energy, and resistivity. The destruction and water content of the surrounding rock can be identified through the physical field information response characteristics. For example, the deformation of the rock can reflect its destruction state. According to the deformation and differences of the surrounding rock in different monitoring areas, the development range of water-conducting fissures can be effectively identified. The process of rock fracture and fissure development will be accompanied by a large amount of energy release. By capturing the energy signal released by the surrounding rock fracture, the development process of the water-conducting channel can be monitored in three dimensions and in real time. The resistivity information of the rock can more sensitively reflect its destruction and water content. According to the resistivity of the surrounding rock, the water-conducting channel and the migration range of water body seepage can be identified.

[0003] At present, it is difficult to fully reflect the dynamic changes of surrounding rock damage and water content by relying on single physical field information. For example, it is difficult to accurately reflect the water content in the fractured rock mass based on deformation alone; the development range of the water channel can be determined based on the acoustic emission energy signal, but the groundwater conduction and diffusion of the water channel cannot be determined; the resistivity of the surrounding rock can reflect the water content of the rock in real time, but its detection results are significantly affected by the environment and have a low resolution. It is necessary to combine other geophysical information to improve the accuracy of resistivity detection data interpretation. There is a coupled response relationship between the multi-physical field information of the surrounding rock during the mining process. For example, when the surrounding rock reaches the deformation threshold, it will be destroyed and release a large amount of energy, and its own resistivity will increase significantly. When the cracks in the surrounding rock are filled with water, the resistivity will be greatly reduced. Comprehensively considering the multi-physical field information generated by surrounding rock damage and water diffusion and migration, the development of mining water channels and groundwater migration processes can be more comprehensively reflected. There are few methods in the existing literature that combine multivariate information to invert the water saturation of rock during load failure. At the same time, there is no report on how to accurately predict the water saturation of rock at a certain moment of load failure using real-time deformation, acoustic emission energy, and resistivity data. Therefore, it is necessary to establish a scientific and reasonable method for inverting the water saturation of rock during load failure. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for determining the water saturation of a rock during a load failure process, which can use the deformation, acoustic emission energy and resistivity data monitored in the laboratory to quickly and quantitatively invert the water saturation of the rock during a load failure process.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A method for determining water saturation in a rock failure process under load, comprising the following steps:

[0007] Step S1: prepare the initial water saturation S w1 The experimental group and the initial water saturation are S w2 The validation group of rock specimens;

[0008] Step S2: Collect and record the strain ε and acoustic emission energy k of the rock specimen during the whole process of uniaxial compression test. U , resistivity k ρ Real-time data;

[0009] Step S3: Obtain strain ε and acoustic emission energy k by fitting U , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between

[0010] Step S4: for rock samples with unknown water saturation, obtain multivariate information to coordinately monitor strain ε and acoustic emission energy k during the experiment. U , resistivity k ρ Substituting the data into the functional relationship, the initial water saturation S of the rock can be obtained by inversion. w ;

[0011] Step S5: Initial water saturation S w The resistivity kρ' measured at any time during the multi-information collaborative monitoring experiment is substituted into the rock water saturation inversion formula to obtain the water saturation S at any time during the rock load failure process. w '.

[0012] As a preferred embodiment, in step S2, a multi-information collaborative monitoring experiment of the rock loading process is carried out on the rock specimens of the experimental group, and the strain amount ε, acoustic emission energy k of the rock specimens during the whole process of the uniaxial compression test are continuously collected and recorded through strain gauges, acoustic emission probes and digital bridges. U , resistivity k ρ Real-time data.

[0013] As a preferred step S3, the strain ε and acoustic emission energy k obtained by fitting U , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between them is as follows:

[0014] ① Strain ε, acoustic emission energy k U , initial water saturation S w1 The following equation is satisfied between the three:

[0015]

[0016] Among them, e is a constant coefficient related to lithology, and f is the water saturation influence coefficient;

[0017] ② Strain ε, resistivity k ρ , initial water saturation S w1 The following equation is satisfied between the three:

[0018] k ρ =(j1+j2·S w1 0.7 )(k1+k2·S w1 -ε) 4 +l1+l2·S w1 1.5 (2)

[0019] Among them, j1, k1, l1 are constant coefficients related to lithology; j2, k2, l2 are water saturation influence coefficients;

[0020] ③Acoustic emission energy k U , resistivity k ρ , initial water saturation S w1 The following equation is satisfied between the three:

[0021]

[0022] Among them: a1, b1, c1, d1 are constant coefficients related to lithology; a2, b2, c2, d2 are water saturation influence coefficients.

[0023] As a preferred step S5, the water saturation S at any time during the rock failure process is w ', including the following steps:

[0024] Step 5.1: Collect strain ε and acoustic emission energy k during the experiment through the rock load multi-information collaborative monitoring experiment U , resistivity k ρ data;

[0025] Step 5.2: Substitute the above data into the functional relationship to obtain the initial water saturation S of the rock. w ;

[0026] Step 5.3: Set the initial water saturation of the rock S w , initial resistivity k ρ , Substituting the resistivity kρ' measured at any time into the following formula, the rock water saturation S corresponding to that time can be obtained: w ',

[0027]

[0028] Preferably, in step S1, rock specimens with different water saturations are prepared by natural immersion method, and the initial water saturation S of each specimen is calculated by calculating the mass difference of the rock specimen before and after immersion. w1 and S w2 .

[0029] The present invention comprehensively considers the deformation, acoustic emission energy, resistivity and other multivariate physical field information generated during the rock load failure process, and solves the technical problems that the traditional inversion method relies on a single resistivity inversion to predict the water saturation of the rock load failure process inaccurately and is greatly interfered by external factors. The method has the technical characteristics of simple operation, comprehensive indicators and strong applicability. In addition, the present invention can be expanded to real-time monitoring, inversion and early warning of the development of water-conducting fractures in the overlying rock strata and the movement of groundwater in the aquifer during the excavation of coal mines, subways, tunnels, etc., solving the technical problems of the difficulty in predicting the real-time water saturation of the mining surrounding rock, limited available data and incomplete evaluation indicators. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0031] Figure 1 This is a flow chart of a method for determining water saturation in a rock load failure process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Embodiment 1:

[0035] like Figure 1 As shown, an embodiment of the present invention provides a method for determining water saturation in a rock failure process under load, comprising the following steps:

[0036] Step S1: Prepare the initial water saturation S w1 and S w2The rock specimen with initial water saturation as S w1 The rock specimens are defined as the experimental group, and the initial water saturation is S w2 The rock specimens with unknown initial water saturation are defined as the verification group; in addition, a group of rock specimens with unknown initial water saturation are prepared;

[0037] Step S2: Conduct a multi-information collaborative monitoring experiment of the rock loading process on the rock specimens of the experimental group. Through strain gauges, acoustic emission probes and digital bridges, continuously collect and record the strain ε and acoustic emission energy k of the rock specimens during the entire uniaxial compression test. U , resistivity k ρ Real-time data;

[0038] Step S3: After the experiment, the “strain ε-energy k” of the rock specimens during the multivariate information collaborative monitoring experiment is plotted. U ”, “Strain ε-resistivity k ρ ”, “Energy k U -Resistivity k ρ "The change curve between the strain ε and the acoustic emission energy k is obtained by fitting. U , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between

[0039] Step S4: The strain ε and acoustic emission energy k monitored during the multivariate information collaborative monitoring experiment of the rock specimens in the verification group are U , resistivity k ρ Substituting the above established functional relationship, the initial water saturation S of the rock specimens in the verification group can be obtained by inversion: w2 ', and with the recorded S w2 Conduct comparative verification;

[0040] Step S5: For rock samples with unknown water saturation, the strain ε and acoustic emission energy k are monitored during the experiment by acquiring multivariate information. U , resistivity k ρ Substituting the data into the functional relationship established in step S3, the initial water saturation S of the rock can be obtained by inversion. w ; The initial water saturation S w The resistivity kρ' measured at any time during the multi-information collaborative monitoring experiment is substituted into the rock water saturation inversion formula to obtain the water saturation S at any time during the rock load failure process. w '.

[0041] As an implementation method of the present invention, the rock selected in step S1 is required to be uniform in texture, without obvious cracks inside, and all taken from the same stone slab. The above rock is processed into a standard cylindrical specimen of 50mm×100mm according to the international rock mechanics test standard. The rock specimens with different water saturations are prepared by natural immersion method, and the initial water saturation S of each sample is calculated by calculating the difference in mass of the rock specimen before and after immersion. w1 and S w2 , and then immediately carry out the multi-information collaborative monitoring experiment of the rock loading process.

[0042] Furthermore, the multi-information collaborative monitoring experiment of rock loading process includes the following steps:

[0043] Step 1.1: First place a piece of Teflon rigid insulating plate in the central area of ​​the lower loading plate, then place a conductive copper sheet in the middle of the insulating plate, and then place the rock sample in the center of the lower conductive copper sheet; then place another conductive copper sheet on the top surface of the rock sample, and finally gently place another piece of Teflon rigid insulating plate on top of the upper conductive copper sheet;

[0044] Step 1.2: Install and connect the acoustic emission monitoring system and install the AE sensor probe. Set the AE threshold voltage value to 100mV and the acquisition frequency to 3MHz;

[0045] Step 1.3: Turn on the static resistance strain gauge host, measure and confirm that the open circuit resistance and short circuit resistance of the resistivity system are normal, connect the monitoring electrode, and the sampling interval is 0.5s;

[0046] Step 1.4: Stress loading system settings: Slowly lower the loading plate on the universal testing machine until the loading plate slightly contacts the insulating plate on the top of the rock sample. Then select the displacement loading control mode to apply the load, and set the loading rate to 0.2mm / min. Finally, input the rock sample number and parameters into the host;

[0047] Step 1.5: Start the strain monitoring system, acoustic emission monitoring system and resistivity monitoring system simultaneously, and monitor the water saturation S in real time. w1 The “ε-k” of the rock sample during uniaxial loading U -k ρ "Multi-parameter response characteristics, until the loaded rock sample is completely destroyed. After the experiment, a new round of rock sample testing will begin.

[0048] After all the experiments were completed, the strain ε and acoustic emission energy k were obtained by fitting. U , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between

[0049] As an implementation of the embodiment of the present invention, in step S3, the strain ε and the acoustic emission energy k obtained by fitting are U , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between them is as follows:

[0050] ① Strain ε, acoustic emission energy k U , initial water saturation S w1 The following equation is satisfied between the three:

[0051]

[0052] Among them, e is a constant coefficient related to lithology, and f is the water saturation influence coefficient, which are taken as 0.547 and 0.0836 respectively;

[0053] ② Strain ε, resistivity k ρ , initial water saturation S w1 The following equation is satisfied between the three:

[0054] k ρ =(j1+j2·S w1 0.7 )(k1+k2·S w1 -ε) 4 +l1+l2·S w1 1.5 (2)

[0055] Among them: j1, k1, l1 are constant coefficients related to lithology, which are taken as 0.129, 1.195, and 0.719 respectively; j2, k2, and l2 are water saturation influence coefficients, which are taken as -0.18, 0.409, and 0.598 respectively;

[0056] ③Acoustic emission energy k U , resistivity k ρ , initial water saturation S w1 The following equation is satisfied between the three:

[0057]

[0058] Among them: a1, b1, c1, d1 are constant coefficients related to lithology, which are taken as 0.129, 1.195, 0.547, 0.719 respectively; a2, b2, c2, d2 are water saturation influence coefficients, which are taken as -0.18, 0.409, -0.0836, 0.598 respectively.

[0059] As an implementation method of the present invention, in step S4, the strain ε and acoustic emission energy k monitored during the multivariate information collaborative monitoring experiment of the rock specimens in the verification group are U , resistivity k ρ Substituting the above established functional relationships (1), (2), and (3) in turn, the inverse prediction value S of the initial water saturation of the rock specimens in the verification group can be obtained: w2 ', and compared with the actual measured initial rock saturation S w2 The applicability of functional relationships (1), (2) and (3) was verified by comparison. After the applicability of the functional relationship was determined, the strain ε and acoustic emission energy k of the rock specimen with unknown water saturation were used in the collaborative monitoring experiment. U , resistivity k ρ The initial water saturation S of the rock can be obtained by w .

[0060] As an implementation method of the present invention, in step S5, the water saturation S at any time during the rock failure process is w ', the calculation process includes the following steps:

[0061] Step 5.1: Collect strain ε and acoustic emission energy k during the experiment through the rock load multi-information collaborative monitoring experiment U , resistivity k ρ data;

[0062] Step 5.2: Substitute the above data into the functional relationships (1), (2), and (3) established by the above method to invert the initial water saturation S of the rock. w ;

[0063] Step 5.3: Set the initial water saturation of the rock S w , initial resistivity k ρ , Substituting the resistivity kρ' measured at any time into the following formula, we can get the rock water saturation S corresponding to that time w ';

[0064]

[0065] The present invention prepares the initial water saturation S w1 The experimental group and the initial water saturation are S w2 The rock specimens of the verification group were used as the test group. The multi-information collaborative monitoring experiment of the rock loading process was carried out on the rock specimens of the experimental group. The strain amount ε and the acoustic emission energy k of the rock specimens during the whole process of the uniaxial compression test were continuously collected and recorded through strain gauges, acoustic emission probes and digital bridges. U , resistivity k ρ Real-time data; strain ε and acoustic emission energy k are obtained by fittingU , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between them is verified by the rock experiment of the verification group. For the rock samples with unknown water saturation, the strain ε and acoustic emission energy k are monitored in the experimental process by obtaining multivariate information. U , resistivity k ρ By substituting the data into the functional relationship established by the above method, the initial water saturation S of the rock can be obtained by inversion. w ; The initial water saturation S w The resistivity kρ' measured at any time during the multi-information collaborative monitoring experiment is substituted into the rock water saturation inversion formula to obtain the water saturation S at any time during the rock load failure process. w The present invention makes up for the fact that the traditional method is difficult to fully reflect the dynamic changes of water saturation during the rock loading and failure process by relying on a single physical field information, and can accurately and truly perform real-time inversion prediction of water saturation at any moment in the rock loading and failure process.

[0066] Embodiment 2:

[0067] like Figure 1 As shown, an embodiment of the present invention provides a method for determining water saturation in a rock failure process under load, comprising the following steps:

[0068] Step S1: Taking rock as an example, prepare the initial water saturation S w1 and S w2 The rock specimen with initial water saturation as S w1 The rock specimens are defined as the experimental group, and the initial water saturation is S w2 The rock specimens with unknown initial water saturation are defined as the verification group; in addition, a group of rock specimens with unknown initial water saturation are prepared;

[0069] Step S2: Conduct a multi-information collaborative monitoring experiment of the rock loading process on the rock specimens of the experimental group. Through strain gauges, acoustic emission probes and digital bridges, continuously collect and record the strain ε and acoustic emission energy k of the rock specimens during the entire uniaxial compression test. U , resistivity k ρ Real-time data;

[0070] Step S3: After the experiment, the “strain ε-energy k” of the rock specimens during the multivariate information collaborative monitoring experiment is plotted. U ”, “Strain ε-resistivity k ρ ”, “Energy k U -Resistivity k ρ "The change curve between the strain ε and the acoustic emission energy k is obtained by fitting. U, resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between

[0071] Step S4: The strain ε and acoustic emission energy k monitored during the multivariate information collaborative monitoring experiment of the rock specimens in the verification group are U , resistivity k ρ Substituting the above established functional relationship, the initial water saturation S of the rock specimens in the verification group can be obtained by inversion: w2 ', and with the recorded S w2 Conduct comparative verification;

[0072] Step S5: For rock samples with unknown water saturation, the strain ε and acoustic emission energy k are monitored during the experiment by acquiring multivariate information. U , resistivity k ρ Substituting the data into the functional relationship established in step S3, the initial water saturation S of the rock can be obtained by inversion. w ; The initial water saturation S w The resistivity kρ' measured at any time during the multi-information collaborative monitoring experiment is substituted into the rock water saturation inversion formula to obtain the water saturation S at any time during the rock load failure process. w '.

[0073] Here, laboratory experiments are taken as an example to verify the method for determining water saturation in the rock load failure process based on multivariate information inversion.

[0074] For the rocks used in the inversion experiment, five specimens with different water saturation were prepared. A total of five specimens were prepared in the experiment. The parameters such as the water content, dry resistivity, and initial resistivity after immersion in water are shown in Table 1.

[0075] Table 1

[0076]

[0077] The preparation process of specimens with different water saturation is as follows:

[0078] ① Determination of natural moisture content: First, record the size and mass of each specimen in its natural state, keep it at a constant temperature of 105°C for 24 hours, then take it out. During this period, test and record the corresponding mass every 2 hours until the mass no longer changes. After cooling, measure and record the final mass of the rock sample. By calculating the difference between the mass of the specimen in its natural state and the mass of the rock sample after drying, the natural moisture content of each rock sample can be obtained.

[0079] ② Preparation of rock samples with different water saturations: The natural immersion method was used to prepare rock samples with different water saturations. First, the water saturation gradient of the rock designed in the experiment was determined to be: 0%, 25%, 50%, 75%, and 100%. The corresponding masses of rocks with different water saturations were calculated. When the mass of the specimens after immersion was close to the target value, the measurement time interval was shortened until each rock sample reached the target mass.

[0080] ③ Test rock sample sealing: For the prepared rock samples with corresponding water saturation, seal them with plastic wrap to prevent water evaporation from interfering with the results of physical and mechanical experiments, and conduct the experiment as soon as possible.

[0081] Experimental process of multi-information collaborative monitoring of rock loading process:

[0082] (1) Placement of rock sample: First, place a rigid Teflon insulating plate in the central area of ​​the lower loading disk, then place a conductive copper sheet in the middle of the insulating plate, then place the rock sample with the AE sensor bonded to the center of the lower conductive copper sheet, then place another conductive copper sheet on the top surface of the rock sample, and finally gently place another rigid Teflon insulating plate on top of the upper conductive copper sheet.

[0083] (2) Strain monitoring system settings: Turn on the static resistance strain gauge host, connect the strain gauge to the strain gauge, and set the strain gauge parameters.

[0084] (3) Acoustic emission monitoring system settings: The AE sensor probes connected to the acoustic emission monitoring system were installed in sequence. The AE threshold voltage value was set to 100 mV and the acquisition frequency was set to 3 MHz.

[0085] (4) Resistivity monitoring system settings: Measure and confirm that the open-circuit resistance and short-circuit resistance of the resistivity system are normal, then connect the monitoring electrodes with a sampling interval of 0.5 s.

[0086] (5) Stress loading system settings: Slowly lower the loading plate on the universal testing machine until the loading plate slightly contacts the insulating plate on the top of the rock sample. Then select the displacement loading control mode to apply the load, and set the loading rate to 0.2 mm / min. Finally, input the rock sample number and parameters into the host.

[0087] (6) “ε-k U -k ρ "Multi-parameter monitoring: The strain monitoring system, acoustic emission monitoring system and resistivity monitoring system are started simultaneously to monitor the "ε-k" of rock samples with different water saturations in real time during uniaxial loading. U -k ρ "Multi-parameter response characteristics until the loaded rock sample is completely destroyed.

[0088] The strain (ε) and released energy (k) during the rock failure process were obtained by using the rock load multivariate information collaborative monitoring experiment. U ), resistivity (k ρ ) data for calculation and inversion; substituting them into the following formulas in turn, the results of the rock water content state inversion example are shown in Table 2.

[0089]

[0090] k ρ =(j1+j2·S w1 0.7 )(k1+k2·S w1 -ε) 4 +l1+l2·S w1 1.5 (2)

[0091]

[0092] It can be seen that the rock S of each example obtained by inversion according to the inversion method is w The actual error values ​​are relatively small, all below 10%. The inversion errors of the rock examples are 2.96% to 8.34%. This shows that the proposed rock water content inversion method is accurate and reliable. For rocks with unknown water saturation, the initial water content and the real-time water content state S during the loading process can be obtained by repeating the above steps during the rock loading process. w .

[0093] In summary, the quantitative inversion method for rock water content proposed in the present invention can be used to invert the "ε-U-ρ" multivariate information data of the rock to obtain the initial water content state S of the rock. w0 and the real-time water content state S during the loading process w , to accurately grasp the water content of the entire process of rock deformation and failure under load,

[0094] Table 2

[0095]

[0096] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for determining water saturation during rock failure under load, characterized in that: The following steps are involved: Step S1: prepare the initial water saturation S w1 The experimental group and the initial water saturation are S w2 The validation set of rock specimens; Step S2: Collect and record the strain ε and acoustic emission energy k of the rock specimen during the whole process of uniaxial compression test. U , resistivity k ρ Real-time data; Step S3: Obtain strain ε and acoustic emission energy k by fitting U , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between Step S4: for rock samples with unknown water saturation, obtain multivariate information to coordinately monitor strain ε and acoustic emission energy k during the experiment. U , resistivity k ρ Substituting the data into the functional relationship, the initial water saturation S of the rock can be obtained by inversion. w ; Step S5: Initial water saturation S w The resistivity kρ' measured at any time during the multi-information collaborative monitoring experiment is substituted into the rock water saturation inversion formula to obtain the water saturation S at any time during the rock load failure process. w '.

2. The method for determining water saturation in a rock load failure process according to claim 1, characterized in that: In step S2, a multi-information collaborative monitoring experiment of the rock loading process is carried out on the rock specimens of the experimental group. The strain amount ε, acoustic emission energy k of the rock specimens during the whole process of the uniaxial compression test are continuously collected and recorded through strain gauges, acoustic emission probes and digital bridges. U , resistivity k ρ Real-time data.

3. The method for determining water saturation in a rock failure process under load according to claim 2, characterized in that: In step S3, the strain ε and acoustic emission energy k obtained by fitting U , resistivity k ρ Any two of the three parameters and the initial water saturation S w1 The functional relationship between them is as follows: ① Strain ε, acoustic emission energy k U , initial water saturation S w1 The following equation is satisfied between the three: Among them, e is a constant coefficient related to lithology, and f is the water saturation influence coefficient; ② Strain ε, resistivity k ρ , initial water saturation S w1 The following equation is satisfied between the three: k ρ =(j1+j2·S w1 0.7 )(k1+k2·S w1 -ε) 4 +l1+l2·S w1 1.5 (2) Among them, j1, k1, l1 are constant coefficients related to lithology; j2, k2, l2 are water saturation influence coefficients; ③Acoustic emission energy k U , resistivity k ρ , initial water saturation S w1 The following equation is satisfied between the three: Among them: a1, b1, c1, d1 are constant coefficients related to lithology; a2, b2, c2, d2 are water saturation influence coefficients.

4. The method for determining water saturation in a rock failure process under load according to claim 2, characterized in that: In step S5, the water saturation S at any time during the rock failure process is w ', including the following steps: Step 5.1: Collect strain ε and acoustic emission energy k during the experiment through the rock load multi-information collaborative monitoring experiment U , resistivity k ρ data; Step 5.2: Substitute the above data into the functional relationship to obtain the initial water saturation S of the rock. w ; Step 5.3: Set the initial water saturation of the rock S w , initial resistivity k ρ , Substituting the resistivity kρ' measured at any time into the following formula, the rock water saturation S corresponding to that time can be obtained: w ', 5. The method for determining water saturation in a rock load failure process according to claim 4, characterized in that: In step S1, rock specimens with different water saturations are prepared by natural immersion method, and the initial water saturation S of each specimen is calculated by calculating the mass difference of the rock specimen before and after immersion. w1 and S w2 .

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