A method for predicting water inrush from fractured rock mass under coupling action of earthquake and pulsating flow

Abstract

The application discloses a method for predicting water inrush of fissured rock mass under the coupling action of earthquakes and pulsating flow, which comprises the following steps: according to the actual need of monitoring the filled fissured rock mass, a scaled sample rock mass is prepared; a seismopulsating flow coupling seepage test is conducted on the scaled sample rock mass; a theoretical permeability coefficient is calculated; a relationship diagram or a relationship formula between the seismic vibration frequency, the amplitude displacement, the hydraulic gradient and the occurrence time of the water inrush accident is obtained; the vibration frequency and the amplitude displacement of the actual earthquake are monitored in real time by using a seismic detector; the pulsating water pressure of the filled fissured rock mass which needs to be monitored is monitored in real time by using a pulse pressure sensor; and then the obtained data is substituted into the above relationship diagram or relationship formula, so that the water inrush and sand gushing disaster of the actual filled fissured rock mass can be predicted.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of geotechnical engineering, and particularly relates to a method for predicting water inrush from fractured rock mass under the coupling action of earthquake and pulsating flow. BACKGROUND

[0002] Under the action of earthquake and overlying seawater pressure, pulsating seepage will be generated in the fractured rock mass, and the water inrush from the mining well under the sea mining will occur, and the geological structure (such as wide fracture, fault, karst cave, karst pipeline, etc.) inside which may be filled with clay, fine sand, gravel, fault mud and other media, and the evolution characteristics and disaster-causing mechanism of water inrush and mud inrush are closely related to the hydrodynamic characteristics of the filling medium. The current seepage-stress coupling research clarifies the influence law of confining pressure and stress on seepage, and describes the fluid-solid coupling effect under the action of stress and water pressure, but does not consider the pulsating characteristics of seepage in fractured rock mass and the influence of seismic load effect on seepage. Therefore, how to realize safe and green mining of marine mineral resources while preventing water inrush accidents is a technical problem to be solved at present, which has great theoretical significance and practical value for prolonging the service life of the mine and preventing water inrush in the mine. SUMMARY

[0003] The main purpose of the application is to provide a method for predicting water inrush from fractured rock mass under the coupling action of earthquake and pulsating flow, which aims to effectively predict water inrush and sand gushing disasters.

[0004] Therefore, the method for predicting water inrush from fractured rock mass under the coupling action of earthquake and pulsating flow provided by the application comprises the following steps:

[0005] (1) According to the actual need to monitor the filling fractured rock mass, a scaled sample rock mass is prepared;

[0006] (2) The scaled sample rock mass is subjected to a seismically-pulsating flow coupling seepage test, and the loss mass m 排 of the filling medium in the fracture, the water channel width a1, the seismic amplitude displacement b1 and the fracture opening b2 are measured in real time during the test;

[0007] (3) The loss mass m 排 of the filling medium, the water channel width a1, the seismic amplitude displacement b1 and the fracture opening b2 measured in the test are used to calculate the theoretical permeability coefficient K:

[0008]

[0009]

[0010] When m1>m 排 , the water inrush from the fractured rock mass under the coupling action of earthquake and pulsating flow is predicted.

[0011] When m1 排 ,

[0012] In the formula: K1 is the partial permeability coefficient of the water-conducting channel in the fracture; K2 is the partial permeability coefficient of the non-water-conducting channel in the fracture; is the porosity of the water-conducting channel part; is the porosity of the non-water-conducting channel part; L is the length of the fracture; b1 is the seismic amplitude displacement; b2 is the fracture opening; m 总 is the total mass of the filling medium in the fracture; m1 is the mass of the water-conducting channel part of the filling medium; m2 is the mass of the non-water-conducting channel part of the filling medium; m 排 is the mass of the filling medium lost; μ is the kinematic viscosity of water; a1 is the width of the water-conducting channel part; a2 is the width of the non-water-conducting channel part; ρ s is the saturated density of the filling medium; d is the particle diameter of the filling medium; a is the fracture width; g is the acceleration of gravity.

[0013] (4) By comparing the permeability coefficients K calculated by the front and rear measurements, when the permeability coefficient sharply rises, it is judged that a water inrush accident occurs at this moment, by changing the seismic intensity, hydraulic gradient, repeating the above test, a plurality of water inrush accident occurrence time data can be obtained, and then the obtained data is fitted, and a relationship diagram or relationship formula of the seismic vibration frequency, amplitude displacement, pulsating water pressure and water inrush accident occurrence time can be obtained;

[0014] (5) The vibration frequency and amplitude displacement of the actual earthquake are monitored in real time by using the seismic detector, and the pulsating water pressure of the filling fractured rock mass that needs to be monitored is monitored in real time by using the pulse pressure sensor, and then the obtained data is substituted into the above relationship diagram or relationship formula, so that the water inrush and sand gushing disaster of the actual filling fractured rock mass can be predicted.

[0015] Specifically, the specific process of the seismic-pulsating flow coupling seepage test is as follows:

[0016] (1) The scale sample rock mass

[0017] The rock is split into two pieces from the middle by using a press, the two pieces of rock are stacked one on top of the other to simulate a natural fracture, and then a filling medium is filled in the fracture, so as to complete the production of the scale sample rock mass;

[0018] (2) Sample loading

[0019] Before loading the sample, a rubber sealing sleeve is matched and fitted around the scale sample rock mass, and then a silicon-titanium alloy fireproof cloth is wound outside the rubber sealing sleeve, the silicon-titanium alloy fireproof cloth covers the natural fracture, so as to seal the four sides of the scale sample rock mass, and water inlets and outlets that are in communication with the natural fracture are respectively arranged on the opposite sides of the scale sample rock mass;

[0020] Then the rock below the scale sample rock mass is matched and fixed in the lower box body of the water inrush test box, and the upper box body is matched and fixed on the rock above the scale sample rock mass, that is, the sample loading of the complete scale sample rock mass is completed;

[0021] (3) Apply water pressure

[0022] The constant pressure water pump is communicated with the water inlet through the water inlet pipe, and the valve and the pressure gauge are connected on the water outlet, the constant pressure water pump is opened, the scale sample rock mass is provided with constant seepage water pressure, and the opening and closing degree of the valve is controlled to achieve the purpose of regulating the pressure in the fracture, so that the pulsating pressure appears in the seepage process, and the water pressure in the rock fracture is measured in real time through the pulse pressure sensor;

[0023] (4) Simulate the loading of the earthquake signal

[0024] The vertical dynamic fatigue loading cylinder is fixedly connected with the upper box body, and the lower box body is fixedly connected with the test table, so that the vertical dynamic fatigue loading cylinder is used to apply a periodic displacement with a certain frequency to the scale sample rock mass, so that the two rocks of the scale sample rock mass move up and down relative to each other, the influence of the earthquake is simulated, and the fatigue loading frequency and the moving displacement of the vertical dynamic fatigue loading cylinder are measured by using the sensor.

[0025] Specifically, the lower box body and the upper box body are fixed on the corresponding rocks through fastening bolts, and the fastening bolts are screwed into the corresponding rocks through the corresponding box bodies.

[0026] Specifically, a rack is arranged on the test table, and the vertical dynamic fatigue loading cylinder is arranged on the rack directly above the test table.

[0027] Specifically, the rock above the scale sample rock mass is made of transparent organic glass material, the rock below the scale sample rock mass is made of granite, and the filling medium in the natural fracture is natural sand.

[0028] Compared with the prior art, the present application has the following beneficial effects: according to the actual need to monitor the filled fracture rock mass, a scale sample rock mass is made, and a seismic-pulsating flow coupling seepage test is carried out on the scale sample rock mass, the related data obtained are used to calculate the theoretical permeability coefficient, when the permeability coefficient sharply rises, it is judged that the water inrush accident occurs at this moment, and through multiple tests, the relationship diagram or relationship formula of the seismic vibration frequency, amplitude displacement, pulsating water pressure and the occurrence time of the water inrush accident is finally obtained, then the vibration frequency and amplitude displacement of the actual earthquake are monitored in real time by using the seismic detector, the pulsating water pressure of the filled fracture rock mass which needs to be monitored is monitored in real time by using the pulse pressure sensor, and then the obtained data is substituted into the above relationship diagram or relationship formula, so that the actual filled fracture rock mass water inrush and sand gushing disaster can be effectively predicted. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0030] Figure 1 is a schematic diagram of a seismic-pulsating flow coupling seepage test device provided by the embodiments of the present application;

[0031] Figure 2 is a sectional view of the water inrush test box;

[0032] Figure 3 is a schematic diagram of a filled fissure rock mass;

[0033] Figure 4 is a fitting diagram of the theoretical value K of the permeability coefficient and the experimental value K0 under a certain working condition;

[0034] 1, natural fissure; 2, scaled sample rock mass; 3, rubber sealing sleeve; 4, water inrush test box; 5, fastening bolt; 6, constant pressure water pump; 7, test table; 8, rack; 9, vertical dynamic fatigue loading cylinder; 10, hydraulic control device; 11, loading oil pump; 12, control system; 13, camera; 14, lower rock mass; 15, upper rock mass. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0036] In the description of the present application, it should be understood that the terms “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0037] In addition, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an indicated number of technical features. Thus, features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise explicitly and specifically limited.

[0038] A method for predicting water inrush from fractured rock mass under the coupling action of earthquake-pulsating flow, comprising the following steps:

[0039] (1) According to the actual need to monitor the filling fractured rock mass, a scaled sample rock mass is made;

[0040] (2) The scaled sample rock mass is subjected to a seismic-pulsating flow coupling seepage test by using a seismic-pulsating flow coupling seepage test device, and the filling medium loss mass m 排 , the water-conducting channel width a1, the seismic amplitude displacement b1 and the fracture opening b2 are measured in real time during the test;

[0041] (3) The filling medium loss mass m 排 , the water-conducting channel width a1, the seismic amplitude displacement b1 and the fracture opening b2 measured in the test are used to calculate the theoretical permeability coefficient K:

[0042]

[0043] When m1 > m 排 ,

[0044] When m1 < m 排 ,

[0045] In the formula: K1 is the permeability coefficient of the water-conducting channel part in the fracture; K2 is the permeability coefficient of the non-water-conducting channel part in the fracture; is the porosity of the water-conducting channel part; is the porosity of the non-water-conducting channel part; L is the fracture length; b1 is the seismic amplitude displacement; b2 is the fracture opening; m 总 is the total mass of the filling medium in the fracture; m1 is the mass of the filling medium in the water-conducting channel part; m2 is the mass of the filling medium in the non-water-conducting channel part; m 排 is the filling medium loss mass in the fracture; μ is the kinematic viscosity of water; a1 is the width of the water-conducting channel part; a2 is the width of the non-water-conducting channel part; ρ s is the saturated density of the filling medium; d is the particle diameter of the filling medium; a is the fracture width; g is the acceleration of gravity.

[0046] (4) through the comparison of the permeability coefficients K calculated by the front and rear measurements, when the permeability coefficient sharply rises, it is judged that the water inrush accident occurs at this moment, by changing the seismic intensity, hydraulic gradient, repeating the above test, a plurality of water inrush accident occurrence time data can be obtained, then the obtained data is fitted, the relationship diagram or relationship formula of the seismic vibration frequency, amplitude displacement, pulsating water pressure and water inrush accident occurrence time can be obtained;

[0047] (5) the vibration frequency and amplitude displacement of the actual earthquake are monitored in real time by using the earthquake detector, the pulsating water pressure of the filling fissured rock mass which needs to be monitored is monitored in real time by using the pulse pressure sensor, then the obtained data is substituted into the above relationship diagram or relationship formula, and the water inrush and sand gushing disaster of the actual filling fissured rock mass can be predicted.

[0048] According to the filling fissured rock mass which needs to be monitored, the scale sample rock mass is made, the earthquake-pulsating flow coupling seepage test is carried out on the scale sample rock mass, the related data is obtained, the theoretical permeability coefficient is calculated, when the permeability coefficient sharply rises, it is judged that the water inrush accident occurs at this moment, and through multiple tests, the relationship diagram or relationship formula of the seismic vibration frequency, amplitude displacement, pulsating water pressure and water inrush accident occurrence time can be obtained, then the vibration frequency and amplitude displacement of the actual earthquake are monitored in real time by using the earthquake detector, the pulsating water pressure of the filling fissured rock mass which needs to be monitored is monitored in real time by using the pulse pressure sensor, then the obtained data is substituted into the above relationship diagram or relationship formula, and the water inrush and sand gushing disaster of the actual filling fissured rock mass can be effectively predicted.

[0049] Referring to Figure 1 and Figure 2 , the specific process that the scale sample rock mass is subjected to the earthquake-pulsating flow coupling seepage test by using the earthquake-pulsating flow coupling seepage test device is as follows:

[0050] (1) scale sample rock mass

[0051] The rock is split into two pieces from the middle by using a press, the two pieces of rock (upper rock body 15 and lower rock body 14) are stacked one on top of the other to simulate the natural fissure 1, then the filling medium is filled in the fissure, so that the scale sample rock mass 2 is completed;

[0052] (2) sample loading

[0053] Before sample loading, the rubber sealing sleeve 3 is matched and placed around the scale sample rock mass 2, then the silicon-titanium alloy fireproof cloth is wound outside the rubber sealing sleeve 3, the silicon-titanium alloy fireproof cloth covers the natural fissure 1, so that the four sides of the scale sample rock mass 2 are sealed, the water inlet and the water outlet which are in communication with the natural fissure 1 are respectively arranged on the opposite sides of the scale sample rock mass 2;

[0054] Afterwards, the rock under the scaled sample rock mass 2 is matched and fixed in the lower box body of the water inrush test box 4, and the upper box body is matched and fixed on the rock above the scaled sample rock mass 2, that is, the sample loading of the complete scaled sample rock mass 2 is completed; the lower box body and the upper box body are both fixed on the corresponding rock through the fastening bolts 5, the fastening bolts 5 are screwed into the corresponding rock through the corresponding box body;

[0055] (3) Apply water pressure

[0056] The constant pressure water pump 6 and the water inlet are communicated through the water inlet pipe, and the valve and the pressure gauge are connected on the water outlet, the constant pressure water pump 6 is opened, the constant seepage water pressure is provided for the scaled sample rock mass 2, and the opening and closing degree of the valve is controlled to achieve the purpose of regulating the pressure in the fissure, so that the pulsating pressure appears in the seepage process, and the water pressure in the rock fissure is measured in real time through the pulse pressure sensor;

[0057] (4) Simulate seismic signal loading

[0058] The lower box body is fixedly connected with the test table 7, the test table 7 is provided with a rack 8, the vertical dynamic fatigue loading cylinder 9 is arranged above the test table 7, the vertical dynamic fatigue loading cylinder 9 is fixedly connected with the upper box body, so that the vertical dynamic fatigue loading cylinder 9 is used to apply a periodic displacement with a certain frequency to the scaled sample rock mass 2, the two rocks of the scaled sample rock mass 2 generate relative up-down movement, the influence of the earthquake is simulated, the fatigue loading frequency and the moving displacement of the vertical dynamic fatigue loading cylinder 9 are measured by using the sensor, the amplitude of the periodic displacement of the vertical dynamic fatigue loading cylinder 9 is the amplitude displacement of the earthquake, and the fatigue loading frequency is the vibration frequency of the vibration, the hydraulic control device 10 is used to control the oil pump 11 to supply oil to the vertical dynamic fatigue loading cylinder 9 to realize the action of the vertical dynamic fatigue loading cylinder 9, and the control system 12 is used to control.

[0059] In order to facilitate the observation of the seepage process, the rock above the scaled sample rock mass is made of transparent organic glass material, the rock below the scaled sample rock mass is made of granite, and the natural sand is used as the filling medium in the natural fissure. An industrial camera 13 is arranged above the upper box body, since the rock above is made of organic glass, the camera can clearly and intuitively shoot and record the changes of the filling layer in the box body and the migration law of the particles.

[0060] The specific derivation process of the theoretical permeability coefficient is as follows:

[0061] Referring to Figure 3 According to the basic principle of fluid mechanics, the cubic law can be obtained:

[0062]

[0063] Where: K is the permeability of the fracture surface, v is the water flow velocity along the fracture surface, and J is the hydraulic gradient along the fracture surface.

[0064] v1 = K1J

[0065] v2 = K2J

[0066] Q1 = v1A1 = v1a1(b1 + b2)

[0067] Q2 = v2A2 = v2a2(b1 + b2)

[0068] Q = K1Ja1(b1 + b2) + K2Ja2(b1 + b2)

[0069] Where: K1 is the permeability coefficient of the water-conducting channel, cm / s; K2 is the permeability coefficient of the non-water-conducting channel portion, cm / s; v1 is the water flow velocity of the water-conducting channel portion, cm / s; v2 is the water flow velocity of the water-conducting channel portion, cm / s; Q1 is the water inflow of the water-conducting channel portion, cm 3 / s; Q2 is the water inflow of the non-water-conducting channel portion, cm 3 / s; b1 is the fracture displacement caused by an earthquake, cm; b2 is the fracture opening, cm; a is the fracture width, cm; a1 is the width of the water-conducting channel portion, cm; a2 is the width of the non-water-conducting channel portion, cm; A1 is the cross-sectional area of the water-conducting channel portion; and A2 is the cross-sectional area of the non-water-conducting channel portion.

[0070] The seepage characteristics of a filled fracture are not only related to the fracture width, but also to the properties of the filling material, such as the particle composition, porosity, and particle diameter of the filling material. Shu Bao-yu et al. used two parallel glass plates to simulate a fracture, with river sand as the filling material. Through experimental research and mathematical derivation, they proposed a formula for calculating the permeability of a filled fracture:

[0071]

[0072] Where: b is the fracture opening; n and d are the porosity and particle diameter of the filling material; g is the acceleration of gravity, 9.8 m / s 2 ; and μ is the kinematic viscosity of water.

[0073] In experiments, it can be clearly seen that the porosity of the entire filling layer does not change uniformly. The fracture surface is divided into two parts, one of which has a rapid loss of particles and a porosity that quickly reaches 1, referred to as the water-conducting channel portion. The other part has a relatively slow change in porosity, referred to as the non-water-conducting channel portion. Therefore, the porosity and permeability are calculated for each of the two parts.

[0074]

[0075] When m1>m 排 hour,

[0076] When m1 < m 排 hour,

[0077] In the formula: K1 is the permeability coefficient of the water-conducting channel portion in the fracture; K2 is the permeability coefficient of the non-water-conducting channel portion in the fracture; The porosity of the water guiding channel section; b1 represents the porosity of the non-water-conducting channel portion; b2 represents the fracture length; b1 represents the seismic amplitude displacement; b2 represents the fracture aperture; m 总 m1 represents the total mass of the filling medium in the fracture; m2 represents the mass of the filling medium in the water-conducting channel portion; m3 represents the mass of the filling medium in the non-water-conducting channel portion; m4 represents the total mass of the filling medium in the fracture. 排 The mass of the filling medium lost in the fracture is μ; the kinematic viscosity of water is a1; the width of the water-conducting channel is a2; the width of the non-water-conducting channel is ρ. s d is the saturated density of the filling medium; d is the particle diameter of the filling medium; a is the crack width; g is the gravitational acceleration.

[0078] The particle loss mass m measured in the experiment 排 Substituting the water channel width a1, the earthquake-induced fracture displacement b1, and the fracture aperture b2 into the above formula, the theoretical value K of the permeability coefficient is calculated. Then, the fitting effect between the theoretical value K and the experimental value K0 is analyzed to verify the effectiveness of the derived formula.

[0079] from Figure 4 As can be seen, the theoretical value K of the permeability coefficient fits the experimental value K0 well. At the moment of water inrush, the permeability coefficient rises sharply. During this period, a large number of sand particles are carried out by the water flow. The loss of sand particles increases the porosity of the filling fractures, further expanding the water-conducting channels within the rock mass and promoting the erosive effect of the water flow. Therefore, a significant increase in the permeability coefficient can be observed. In practical engineering, this theoretical formula can be used to predict water inrush and sand inrush disasters, providing a predictive reference for actual construction disasters.

[0080] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0081] Meanwhile, if the present application discloses or involves mutually fixedly connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachably fixed connection (for example, using bolt or screw connection), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, integrally formed by using casting process) (obviously, except for the cases where integral forming process cannot be used).

[0082] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the present application include the approximate, similar or close state or shape, unless otherwise stated. Any component provided by the present application can be assembled from multiple individual components or manufactured as a single component by integral forming process.

[0083] The above embodiments are only examples for clearly illustrating the present application, and are not limitations on the embodiments. Based on the above description, other different forms of changes or variations can also be made by those skilled in the art. Here, it is neither necessary nor possible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for predicting water inrush in fractured rock masses under earthquake-pulsating flow coupling, characterized in that, Includes the following steps: (1) Prepare scaled-down rock mass samples based on the rock mass with filled fractures that need to be monitored in practice. (2) Seismic-pulsating flow coupled seepage tests were conducted on scaled-down rock samples, and the mass of the filling medium lost from the fractures during the test was recorded. 排 Real-time measurements were taken of the water diversion channel width a1, seismic amplitude displacement b1, and fracture aperture b2. (3) The mass of filling medium lost, m, was measured by the experiment. 排 Calculate the theoretical permeability coefficient K based on the water channel width a1, earthquake amplitude displacement b1, and fracture aperture b2. When m1>m 排 hour, When m1 < m 排 hour, In the formula: K1 is the permeability coefficient of the water-conducting channel portion in the fracture; K2 is the permeability coefficient of the non-water-conducting channel portion in the fracture; The porosity of the water guiding channel section; b1 represents the porosity of the non-water-conducting channel portion; b2 represents the fracture length; b1 represents the seismic amplitude displacement; b2 represents the fracture aperture; m 总 m1 represents the total mass of the filling medium in the fracture; m2 represents the mass of the filling medium in the water-conducting channel portion; m3 represents the mass of the filling medium in the non-water-conducting channel portion; m4 represents the total mass of the filling medium in the fracture. 排 The mass of the filling medium lost in the fracture is μ; the kinematic viscosity of water is a1; the width of the water-conducting channel is a2; the width of the non-water-conducting channel is ρ. s d is the saturation density of the filling medium; d is the particle diameter of the filling medium; a is the crack width; g is the gravitational acceleration. (4) By comparing the permeability coefficient K calculated before and after, when the permeability coefficient rises sharply, it is determined that a water inrush accident occurred at that moment. By changing the earthquake intensity and hydraulic gradient, the above test can be repeated to obtain multiple sets of data on the time of water inrush accidents. Then, by fitting the obtained data, the relationship between earthquake vibration frequency, amplitude displacement, pulsating water pressure and the time of water inrush accident can be obtained as a graph or formula. (5) The vibration frequency and amplitude displacement of the actual earthquake are monitored in real time by using a seismic detector, and the pulsating water pressure of the filled fracture rock mass is monitored in real time by using a pulse pressure sensor. Then, the obtained data is substituted into the above relationship graph or formula to predict the actual water inrush and sand inrush disaster of the filled fracture rock mass.

2. The method for predicting water inrush in fractured rock masses under earthquake-pulsating flow coupling as described in claim 1, characterized in that, The specific process of the earthquake-pulsating flow coupled seepage test is as follows: (1) Scaled-down sample rock mass A press is used to split the rock into two pieces, and the two pieces of rock are stacked one on top of the other to simulate a natural fissure. Then, the fissure is filled with a filling medium to complete the production of a scaled-down sample rock mass. (2) Sample preparation Before loading the sample, rubber sealing sleeves are fitted around the rock body of the scaled sample. Then, silicon-titanium alloy fireproof cloth is wrapped around the rubber sealing sleeves. The silicon-titanium alloy fireproof cloth covers the natural fissures to seal the rock body of the scaled sample. Water inlets and outlets that communicate with the natural fissures are provided on opposite sides of the rock body of the scaled sample. Then, the rock below the scaled-down sample rock mass is matched and fixed in the lower box of the water inrush test box, and the upper box matching solid is placed on the rock above the scaled-down sample rock mass to complete the sample loading of the scaled-down sample rock mass. (3) Apply water pressure The constant pressure water pump is connected to the inlet through the inlet pipe, and a valve and pressure gauge are connected to the outlet. The constant pressure water pump is turned on to provide a constant seepage water pressure to the scaled sample rock mass. By controlling the opening and closing of the valve, the pressure inside the fissure is regulated, so that pulsating pressure occurs during the seepage process. The water pressure inside the rock fissure is measured in real time through a pulse pressure sensor. (4) Simulated seismic signal loading The vertical dynamic fatigue loading cylinder is fixedly connected to the upper box, and the lower box is fixedly connected to the test bench. The vertical dynamic fatigue loading cylinder is used to apply periodic displacement with a certain frequency to the scaled sample rock mass, so that the two rocks of the scaled sample rock mass move relative to each other up and down, simulating the effect of an earthquake. Sensors are used to measure the fatigue loading frequency and displacement of the vertical dynamic fatigue loading cylinder.

3. The method for predicting water inrush in fractured rock masses under earthquake-pulsating flow coupling as described in claim 2, characterized in that: The upper box and the lower box are fixed to the corresponding rocks by fastening bolts, which pass through the corresponding box and are screwed into the corresponding rocks.

4. The method for predicting water inrush in fractured rock masses under earthquake-pulsating flow coupling as described in claim 2, characterized in that: The test bench is equipped with a frame, and the vertical dynamic fatigue loading cylinder is located on the frame directly above the test bench.

5. The method for predicting water inrush in fractured rock masses under earthquake-pulsating flow coupling as described in claim 2, characterized in that: The rock above the scaled-down sample rock mass is made of transparent plexiglass, the rock below the scaled-down sample rock mass is made of granite, and the filling medium in the natural fissures is natural sand.

Images