Experimental method and system for influence of hydraulic fracturing fractures on coal and rock mass cuttability

Abstract

The invention provides an experimental method and system for the influence of hydraulic fracturing fractures on coal and rock mass.The method comprises the steps that a plurality of fractured rock samples containing prefabricated fractures are prepared, fracture parameters of all the fractured rock samples are not completely the same, a complete rock sample is prepared as a control group, and the control group is used for determining the influence of hydraulic fracturing fractures on the coal and rock massability; the fracture parameters comprise at least one of the fracture number, the fracture half length, the fracture connectivity rate and the fracture inclination angle; the hob is driven to perform cutting rock breaking operation on the rock sample, and propulsive force data and torque data in the operation process are collected; based on the propulsive force data and the torque data, the influence rule of the fracture parameters on the coal rock mass cuttability is analyzed, and analysis includes calculation of at least one of the mean propulsive force, the mean torque and the rock breaking specific energy consumption. According to the invention, a set of experimental scheme capable of systematically and quantitatively researching the influence rule of single or composite fracture parameters on the coal rock mass cuttable property can be provided, and solid experimental data support and theoretical guidance are provided for accurate design and parameter optimization of an underground hydraulic fracturing weakening technology.

Description

Technical Field

[0001] This invention relates to the fields of mining engineering and rock mechanics, and in particular to an experimental method and system for the influence of hydraulic fracturing fractures on the shearability of coal and rock masses. Background Technology

[0002] In coal mine hard rock tunnel excavation, the high hardness and strength of the rock are the main bottlenecks restricting excavation efficiency. When breaking hard rock, the cutting head of a roadheader generally faces a series of severe challenges, such as huge cutting resistance, severe tool wear, high specific energy consumption, and slow tunneling speed, which directly affect the mine's production efficiency and economy.

[0003] Hydraulic fracturing, as an effective rock mass modification method, has been introduced into the coal mining industry, mainly for roof weakening and coal seam permeability enhancement. Its technical principle lies in artificially creating and expanding a fracture network by injecting high-pressure fluid into the target rock strata, thereby significantly reducing the overall strength and integrity of the rock mass. Based on this principle, hydraulic fracturing, as an advanced pretreatment measure before roadway excavation, can theoretically effectively weaken the rock mass ahead of the working face, improve its cutability, and thus achieve the goals of increasing excavation efficiency and reducing cutting energy consumption and tool wear.

[0004] However, research on the targeted application of hydraulic fracturing technology to improve tunnel excavation efficiency is still in its early stages. A key unresolved scientific question is: to what extent, and according to what inherent laws, does the complex fracture network generated by hydraulic fracturing (specifically including parameters such as the number, geometric size, and spatial distribution of fractures) improve the shearability of rock mass? Current technology lacks a dedicated experimental method and system capable of accurately simulating different hydraulic fracturing fracture parameters and directly and quantitatively testing the impact of these parameters on key indicators such as rock mass cutting load and specific energy consumption. This results in a lack of reliable theoretical and experimental basis for the optimal design of hydraulic fracturing parameters in practical engineering, limiting the precise and efficient application of hydraulic fracturing technology in the coal mining field. Summary of the Invention

[0005] The purpose of this invention is to provide an experimental method and system for studying the influence of hydraulic fracturing fractures on the shearability of coal and rock masses. By preparing standardized pre-fabricated fractured rock samples, it is possible to precisely control and study each specific fracture parameter. This provides an experimental scheme that can systematically and quantitatively study the influence of single or combined fracture parameters on the shearability of coal and rock masses, thereby providing solid experimental data support and theoretical guidance for the precise design and parameter optimization of downhole hydraulic fracturing weakening technology.

[0006] To achieve the above objectives, the present invention provides an experimental method and system for assessing the influence of hydraulic fracturing fractures on the shearability of coal and rock masses, comprising:

[0007] Multiple fractured rock samples containing pre-fabricated fractures are prepared, and the fracture parameters of each fractured rock sample are not exactly the same. Complete rock samples are prepared as a control group. The fracture parameters include at least one of the following: number of fractures, fracture half-length, fracture connectivity and fracture dip angle.

[0008] The drive cutter performs cutting and rock-breaking operations on the rock sample, and collects propulsion force and torque data during the operation.

[0009] Based on the propulsion force data and the torque data, the influence of the fracture parameters on the cutability of coal and rock mass is analyzed. The analysis includes calculating at least one of the mean propulsion force, mean torque, and rock breaking energy consumption.

[0010] Optionally, the method for analyzing the influence of the fracture parameters on the shearability of coal and rock mass includes: based on the propulsion force data and the torque data, plotting the curve of propulsion force versus time / drilling depth, and / or the curve of torque versus time / drilling depth, and / or the curve of rock breaking specific energy consumption versus time / drilling depth.

[0011] Optionally, the rock-breaking specific energy consumption H is calculated. w The formulas include:

[0012] ,

[0013] Among them, H r For rotary cutting rock breaking specific energy consumption, H h To achieve the energy consumption ratio of drilling cutting rock breaking, W r The work done for the rotary cutting, W h The work done for drilling and cutting, V r P represents the volume of the truncated rock sample. m t is the motor power when cutting the rock sample, and t is the time consumed by the roller cutter to break the rock, in meters. r ρ represents the mass of the rock sample. r F represents the density of the rock sample. q Where L is the propulsion force, n is the drilling depth, and T is the hobbing speed. R For torque.

[0014] Optionally, the rock-breaking specific energy consumption H is calculated. w The formulas include:

[0015] ,

[0016] Among them, t p At the moment of maximum propulsion, L p This is the drilling depth when the thrust is at its maximum.

[0017] Optionally, the fractured rock sample is cast using mortar concrete, and the fractured rock sample has flaky materials embedded inside to simulate the fractures generated by hydraulic fracturing; the intact rock sample is collected and prepared from the construction site.

[0018] Optionally, methods to make the fracture parameters of each fractured rock sample not exactly the same include: changing the number and / or size and / or position and / or angle of the flakes.

[0019] Based on another aspect of the present invention, the present invention also provides an experimental system for studying the influence of hydraulic fracturing fractures on the shearability of coal and rock masses, which is used to implement the experimental method described above, the experimental system comprising:

[0020] A roller cutter rock breaking test bench is used to fix rock samples;

[0021] The power module is used to drive the hob rotation and feed;

[0022] The data acquisition module is used to collect propulsion and torque data during the operation.

[0023] The calculation and analysis module analyzes the influence of fracture parameters on the shearability of coal and rock masses based on the propulsion force data and the torque data.

[0024] Optionally, the power module includes a moving unit and a rotating unit. The moving unit includes a propulsion cylinder and is used to provide linear feed for the hob. The rotating unit includes a hydraulic motor and is used to drive the hob to rotate.

[0025] Optionally, the data acquisition module includes a first pressure sensor, a second pressure sensor, and a displacement sensor for measuring the cutting stroke of the hob. The first pressure sensor is installed in the oil circuit of the propulsion cylinder to measure the propulsion force data, and the second pressure sensor is installed in the oil circuit of the hydraulic motor to measure the torque data.

[0026] Optionally, the moving unit integrates a first throttle valve for controlling the feed speed of the hob, and the rotating unit integrates a second throttle valve for controlling the rotation speed of the hob.

[0027] As configured above, this invention prepares fractured rock samples by simulating fractures with sheet-like materials and pouring mortar concrete. The number and / or size and / or position and / or angle of the sheet-like materials can be changed to give the fractured rock samples specific fracture parameters (number of fractures, half-length of fractures, fracture connectivity, and fracture dip angle). A cutting cutter is used to cut and break fractured rock samples with different fracture parameters and intact rock samples. Data from the operation is collected and analyzed, thereby systematically analyzing the influence of changes in single parameters such as the number of fractures, half-length of fractures, fracture connectivity, and fracture dip angle on the mean load (mean propulsion force and mean torque) and rock breaking energy consumption, and establishing a quantitative relationship between fracture parameters and the cutability of coal and rock mass. This invention employs a high-precision data acquisition module to obtain dynamic load curves during rock breaking. It not only extracts the mean load (mean thrust and mean torque) as a direct indicator but also introduces the comprehensive indicator of "rock breaking specific energy consumption," establishing a calculation formula for this value. This scientifically evaluates the energy breaking efficiency of different fractured rock samples, making the evaluation system more comprehensive and accurate. The roller cutter rock breaking method used in this invention can simulate the actual working state of the cutting head of a tunneling machine. The measured thrust, torque, and other parameters are directly related to on-site tunneling efficiency, cutter wear, and energy consumption. The experimental results have guiding value for engineering practice. In summary, this invention, by preparing standardized prefabricated fractured rock samples, allows for precise control and study of each specific fracture parameter. It provides a systematic and quantitative experimental scheme for studying the influence of single or combined fracture parameters on the shearability of coal and rock masses, thus providing solid experimental data support and theoretical guidance for the precise design and parameter optimization of downhole hydraulic fracturing weakening technology. Attached Figure Description

[0028] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0029] Figure 1 This is a schematic diagram of an experimental method for studying the effect of hydraulic fracturing fractures on the shearability of coal and rock masses according to an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram illustrating the changes in propulsion force and torque with the hob cutting stroke when the fracture connectivity is 0.2, according to an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram showing the changes in propulsion force and torque with the hob cutting stroke when the fracture connectivity is 0.4, according to an embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram illustrating the changes in propulsion force and torque with the hob cutting stroke when the fracture connectivity is 0.6, according to an embodiment of the present invention.

[0033] Figure 5 This is a schematic diagram illustrating the changes in propulsion force and torque with the hob cutting stroke when the fracture connectivity is 0.8, according to an embodiment of the present invention.

[0034] Figure 6 This is a schematic diagram illustrating the changes in propulsion force and torque with the hob cutting stroke when the number of cracks is 3, according to an embodiment of the present invention.

[0035] Figure 7 This is a schematic diagram illustrating the changes in propulsion force and torque with the hob cutting stroke when the number of cracks is 6, according to an embodiment of the present invention.

[0036] Figure 8 This is a schematic diagram illustrating the changes in propulsion force and torque with the hob cutting stroke when the number of cracks is 9, according to an embodiment of the present invention.

[0037] Figure 9 This is a schematic diagram showing the changes in propulsion force and torque with the cutting stroke of the hob when the crack inclination angle is 30°, according to an embodiment of the present invention.

[0038] Figure 10 This is a schematic diagram showing the changes in propulsion force and torque with the hob cutting stroke when the crack inclination angle is 45° according to an embodiment of the present invention;

[0039] Figure 11 This is a schematic diagram illustrating the changes in propulsion force and torque with the cutting stroke of the hob when the crack inclination angle is 60°, according to an embodiment of the present invention. Detailed Implementation

[0040] In this document, unless otherwise stated, the terms “upper,” “lower,” “left,” “right,” “inner,” “outer,” “front,” “back,” “top,” “bottom,” etc., are used to indicate orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a characteristic orientation and operation, and therefore should not be construed as a limitation of the invention.

[0041] The specific embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0042] Figure 1 This is a schematic diagram of an experimental method for investigating the effect of hydraulic fracturing fractures on the shearability of coal and rock masses according to an embodiment of the present invention. Please refer to it. Figure 1 This invention provides an experimental method for studying the influence of hydraulic fracturing fractures on the shearability of coal and rock masses, which includes steps S1 and S2. Steps S1 and S2 are described in detail below.

[0043] Step S1: Prepare multiple fractured rock samples containing pre-fabricated fractures. The fracture parameters of each fractured rock sample are not exactly the same. Prepare complete rock samples as a control group. The fracture parameters include at least one of the following: number of fractures, fracture half-length, fracture connectivity, and fracture dip angle.

[0044] Furthermore, the fractured rock sample is constructed using mortar concrete, and sheet-like materials are pre-embedded inside the sample to simulate fractures generated by hydraulic fracturing. That is, mortar concrete simulates the coal and rock mass, and sheet-like materials simulate the fractures within the coal and rock mass. For example, the sheet-like materials can be plastic sheets, with a thickness of, for example, 1 mm. The intact rock sample is collected and prepared from the construction site. It is understood that the intact rock sample is a coal and rock mass that has not been hydraulically fractured (has no fractures) and is prepared from the construction site.

[0045] It is understood that the fact that the fracture parameters of each fractured rock sample are not completely identical means that at least one of the specific parameters among the fracture parameters is different. For example, at least one of the four parameters—the number of fractures, the half-length of the fracture, the connectivity of the fracture, and the dip angle—is different for each fractured rock sample. Therefore, it is possible to study the influence of changes in a single parameter or a combination of parameters on the shearability of coal and rock masses. Methods to make the fracture parameters of each fractured rock sample not completely identical include changing the number and / or size and / or position and / or angle of the plaques. For example, one plaque represents one fracture.

[0046] Preferably, before preparing fractured rock samples, the range of values ​​for the fracture parameters to be studied can be defined based on the target engineering geological conditions, and multiple fractured rock samples containing different fracture parameters can be prepared and processed within the range of values ​​for the fracture parameters.

[0047] Step S2: Drive the cutter to perform cutting and rock-breaking operations on the rock sample, and collect propulsion force and torque data during the operation. It is understood that the rock sample includes fractured rock samples and intact rock samples. The cutter can be, for example, a disc cutter.

[0048] Before performing rock-breaking operations, the rock sample needs to be fixed in place, for example, inside a test chamber. The cutting parameters of the hob also need to be set, such as axial movement speed, rotational speed, and depth of cut. The data acquisition module is then activated, and its data recording function is enabled. The rotating and moving units are then activated sequentially, driving the hob to perform rock-breaking operations according to the preset cutting parameters. Throughout the entire cutting stroke, the data acquisition module monitors and records the propulsion force and torque data in real time.

[0049] Step S3: Based on the propulsion force data and the torque data, analyze the influence of the fracture parameters on the cutability of the coal and rock mass. The analysis includes calculating at least one of the mean propulsion force, mean torque, and rock-breaking energy consumption. In this embodiment, the mean propulsion force and mean torque are collectively referred to as the mean load. The mean propulsion force is obtained by averaging the propulsion force during the cutting process, and the mean torque is obtained by averaging the torque during the cutting process. The mean propulsion force and mean torque are used as direct evaluation indicators for assessing the cutting resistance of the coal and rock mass.

[0050] The method for analyzing the influence of the fracture parameters on the cutability of coal and rock mass includes: based on the propulsion force data and the torque data, plotting the curves of propulsion force versus time / drilling depth, and / or the curves of torque versus time / drilling depth, and / or the curves of rock breaking energy consumption versus time / drilling depth.

[0051] The analytical methods may also include: comparing the mean load and rock-breaking energy consumption of rock samples with different fracture parameters with the corresponding test results of intact rock samples; systematically analyzing the influence of changes in single parameters such as the number of fractures, fracture half-length, fracture connectivity, and fracture dip angle on the mean load and rock-breaking energy consumption, and establishing a quantitative relationship between fracture parameters and the shearability of coal and rock mass. For example... Figures 2 to 5 The study demonstrated the influence of the parameter of fracture connectivity.

[0052] It is understandable that the energy consumed during the cutting and rock-breaking process of rotary cutter drilling includes the energy consumed by rotary cutting and rock-breaking, as well as the energy consumed by drilling and cutting. The specific energy consumption H for rock breaking is then calculated. w The formulas include:

[0053] ,

[0054] Among them, H r The energy consumption of rotary rock breaking is kW·h / m 3 H h The energy consumption per unit area for drilling cutting and rock breaking is kW·h / m 3 W r Work done for rotary cutting, kW·h; W h Work done for drilling and cutting, kW·h; V r The volume of the truncated rock sample is m. 3 ;P m t is the motor power during rock cutting (kW); t is the time consumed by the roller cutter in rock breaking (h); m r The mass of the rock sample is expressed in kg; ρ r The density of the rock sample is kg / m³. 3 ;F q The thrust is N; L is the drilling depth in mm; n is the hobbing speed in r / min; TR For torque, N·m.

[0055] Since the torque and propulsion force of the cutting roller increase continuously with drilling time, calculating the energy consumed by the roller rotation and drilling to cut the rock sample requires integrating the torque-time and traction power-time curves. Therefore, the rock-breaking specific energy consumption H can be calculated. w The integral form of the formulas includes:

[0056] ,

[0057] Among them, t p At the moment of maximum propulsion, h; L p The drilling depth is measured in mm when the thrust is at its maximum.

[0058] Based on another aspect of the present invention, the present invention also provides an experimental system for studying the influence of hydraulic fracturing fractures on the shearability of coal and rock masses, which is used to implement the experimental method described above. The experimental system includes a roller cutter rock breaking test bench, a power module, a data acquisition module, and a calculation and analysis module.

[0059] The roller cutter rock breaking test bench is used to fix rock samples. The roller cutter rock breaking test bench consists of a test chamber and a test platform. The test chamber is installed on the test platform, and the rock sample is subjected to cutting and rock breaking operations in the test chamber.

[0060] The power module is used to drive the hob's rotation and feed. Specifically, the power module includes a moving unit and a rotating unit. The moving unit includes a feed cylinder and is used to provide linear feed to the hob; the rotating unit includes a hydraulic motor and is used to drive the hob to rotate. It is understood that the moving unit and the rotating unit also each have hydraulic circuits to drive the feed cylinder and the hydraulic motor via hydraulic power. Preferably, the moving unit integrates a first throttle valve for precisely controlling the hob's feed speed, and the rotating unit integrates a second throttle valve for precisely controlling the hob's rotation speed.

[0061] The data acquisition module is used to collect propulsion force and torque data during the operation, i.e., to monitor and record key physical parameters during the cutter rock breaking process in real time. Specifically, the data acquisition module includes a first pressure sensor, a second pressure sensor, and a displacement sensor for measuring the cutter cutting stroke. The first pressure sensor is installed in the hydraulic circuit of the propulsion cylinder to measure the propulsion force data, and the second pressure sensor is installed in the hydraulic circuit of the hydraulic motor to measure the torque data. The displacement sensor, for example, can be a drawstring displacement sensor, used to measure the cutter cutting stroke, i.e., to measure the drilling depth.

[0062] The calculation and analysis module analyzes the influence of fracture parameters on the cutability of coal and rock mass based on the propulsion force data and the torque data.

[0063] For example, a computer and software can be used to install data acquisition and analysis software to set acquisition parameters, display data curves in real time, and store raw data such as thrust-time and torque-time.

[0064] The data acquisition module also includes a data acquisition card, such as a multi-functional data acquisition card. The data acquisition card is electrically connected to the computer, and the signal output terminals of the first pressure sensor, the second pressure sensor, and the displacement sensor are electrically connected to the data acquisition card. The data acquisition card is used to receive and convert sensor signals, ensuring the synchronous and real-time acquisition of propulsion, torque, and displacement signals.

[0065] After the rock sample is prepared in step S1, connect and debug the various modules of the experimental system to ensure the stable operation of the power module and data acquisition module.

[0066] As configured above, this invention prepares fractured rock samples by simulating fractures with sheet-like materials and pouring mortar concrete. The number and / or size and / or position and / or angle of the sheet-like materials can be changed to give the fractured rock samples specific fracture parameters (number of fractures, half-length of fractures, fracture connectivity, and fracture dip angle). A cutting cutter is used to cut and break fractured rock samples with different fracture parameters and intact rock samples. Data from the operation is collected and analyzed, thereby systematically analyzing the influence of changes in single parameters such as the number of fractures, half-length of fractures, fracture connectivity, and fracture dip angle on the mean load (mean propulsion force and mean torque) and rock breaking energy consumption, and establishing a quantitative relationship between fracture parameters and the cutability of coal and rock mass. This invention employs a high-precision data acquisition module to obtain dynamic load curves during rock breaking. It not only extracts the mean load (mean thrust and mean torque) as a direct indicator but also introduces the comprehensive indicator of "rock breaking specific energy consumption," establishing a calculation formula for this value. This scientifically evaluates the energy breaking efficiency of different fractured rock samples, making the evaluation system more comprehensive and accurate. The roller cutter rock breaking method used in this invention can simulate the actual working state of the cutting head of a tunneling machine. The measured thrust, torque, and other parameters are directly related to on-site tunneling efficiency, cutter wear, and energy consumption. The experimental results have guiding value for engineering practice. In summary, this invention, by preparing standardized prefabricated fractured rock samples, allows for precise control and study of each specific fracture parameter. It provides a systematic and quantitative experimental scheme for studying the influence of single or combined fracture parameters on the shearability of coal and rock masses, thus providing solid experimental data support and theoretical guidance for the precise design and parameter optimization of downhole hydraulic fracturing weakening technology.

[0067] The following are specific examples:

[0068] Example 1

[0069] (1) Experimental procedure: Keep the fracture connectivity rate k=0.6, fracture dip angle 60°, and fracture half length a=90mm unchanged, prepare and test fracture rock samples with 3, 6 and 9 fractures respectively.

[0070] (2) Results and Analysis: Plot curves showing the changes in thrust, torque, rock-breaking energy consumption, etc., with the number of fractures, fracture dip angle, and fracture half-length (taking thrust as an example, see...). Figures 6 to 8 (The rock breaking energy consumption is calculated using the aforementioned rock breaking energy consumption formula.) Data shows that as the number of fractures increases, the average propulsion force decreases significantly from 3.5 kN to 2.0 kN, indicating that increased fracture density makes the coal and rock mass easier to break.

[0071] This result provides experimental evidence for determining the optimal fracture density required for downhole fracturing.

[0072] Example 2

[0073] (1) Experimental procedure: Keep the number of fractures at 6, the fracture connectivity rate k=0.6, and the fracture half length a=90mm unchanged, and prepare and test fracture rock samples with fracture dip angles of 30°, 45° and 60° respectively.

[0074] (2) Results and Analysis: Plot the curves of propulsion force, mean torque and specific energy consumption as a function of fracture dip angle (see details). Figures 9 to 11 The results show that a fracture dip angle of 60° has the most significant effect on reducing the mean load and rock-breaking energy consumption. This is because this angle is more conducive to activating fracture propagation and penetration under cutting loads. This finding has important guiding significance for optimizing the azimuth angle of hydraulic fracturing boreholes.

[0075] It should be noted that references to "an embodiment," "an embodiment," "a specific embodiment," "some embodiments," etc., in the specification only indicate that the described embodiment may include a specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in conjunction with an embodiment, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.

[0076] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0077] It should also be noted that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

[0078] It should also be understood that, unless otherwise specified or indicated, the terms “first,” “second,” “third,” etc., in the specification are used only to distinguish the various components, elements, and steps in the specification, and not to indicate the logical or sequential relationships between the various components, elements, and steps.

[0079] Furthermore, it should be recognized that the terminology described herein is used only to describe particular embodiments and not to limit the scope of the invention. It must be noted that the singular forms “a” and “an” used herein and in the appended claims include plural bases unless the context clearly indicates otherwise. For example, a reference to “a step” or “an apparatus” means a reference to one or more steps or apparatuses, and may include secondary steps and secondary apparatuses. All conjunctions used should be understood in the broadest sense. Also, the word “or” should be understood to have the definition of logical “or” rather than logical “exclusive OR”, unless the context clearly indicates otherwise. Furthermore, implementation of the methods and / or devices in embodiments of the invention may include performing selected tasks manually, automatically, or in combination.

Claims

1. An experimental method for the influence of hydraulic fracturing fractures on the shearability of coal and rock masses, characterized in that, include: Multiple fractured rock samples containing pre-fabricated fractures are prepared, and the fracture parameters of each fractured rock sample are not exactly the same. Complete rock samples are prepared as a control group. The fracture parameters include at least one of the following: number of fractures, fracture half-length, fracture connectivity and fracture dip angle. The drive cutter performs cutting and rock-breaking operations on the rock sample, and collects propulsion force and torque data during the operation. Based on the propulsion force data and the torque data, the influence of the fracture parameters on the cutability of coal and rock mass is analyzed. The analysis includes calculating at least one of the mean propulsion force, mean torque, and rock breaking energy consumption.

2. The experimental method for the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 1, characterized in that, The method for analyzing the influence of the fracture parameters on the cutability of coal and rock mass includes: based on the propulsion force data and the torque data, plotting the curves of propulsion force versus time / drilling depth, and / or the curves of torque versus time / drilling depth, and / or the curves of rock breaking energy consumption versus time / drilling depth.

3. The experimental method for the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 1, characterized in that, Calculate the specific energy consumption H for rock breaking. w The formulas include: ， Among them, H r For rotary cutting rock breaking specific energy consumption, H h To achieve the energy consumption ratio of drilling cutting rock breaking, W r The work done for the rotary cutting, W h The work done for drilling and cutting, V r P represents the volume of the truncated rock sample. m t is the motor power when cutting the rock sample, and t is the time consumed by the roller cutter to break the rock, in meters. r ρ represents the mass of the rock sample. r F represents the density of the rock sample. q Where L is the propulsion force, n is the drilling depth, and T is the hobbing speed. R For torque.

4. The experimental method for the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 3, characterized in that, Calculate the specific energy consumption H for rock breaking. w The formulas include: ， Among them, t p At the moment of maximum propulsion, L p This is the drilling depth when the thrust is at its maximum.

5. The experimental method for the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 1, characterized in that, The fractured rock sample was cast using mortar concrete, and the interior of the fractured rock sample was pre-embedded with sheet-like objects to simulate the fractures generated by hydraulic fracturing; the intact rock sample was collected and prepared from the construction site.

6. The experimental method for the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 5, characterized in that, Methods to make the fracture parameters of each fractured rock sample not exactly the same include: changing the number and / or size and / or position and / or angle of the flakes.

7. An experimental system for studying the effect of hydraulic fracturing fractures on the shearability of coal and rock masses, used to implement the experimental method as described in any one of claims 1 to 6, characterized in that, The experimental system includes: A roller cutter rock breaking test bench is used to fix rock samples; The power module is used to drive the hob rotation and feed. The data acquisition module is used to collect propulsion and torque data during the operation. The calculation and analysis module analyzes the influence of fracture parameters on the shearability of coal and rock masses based on the propulsion force data and the torque data.

8. The experimental system for studying the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 7, characterized in that, The power module includes a moving unit and a rotating unit. The moving unit includes a propulsion cylinder and is used to provide linear feed for the hob. The rotating unit includes a hydraulic motor and is used to drive the hob to rotate.

9. The experimental system for studying the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 8, characterized in that, The data acquisition module includes a first pressure sensor, a second pressure sensor, and a displacement sensor for measuring the cutting stroke of the hob. The first pressure sensor is installed in the oil circuit of the propulsion cylinder to measure the propulsion force data, and the second pressure sensor is installed in the oil circuit of the hydraulic motor to measure the torque data.

10. The experimental system for studying the influence of hydraulic fracturing fractures on the shearability of coal and rock masses as described in claim 8, characterized in that, The moving unit integrates a first throttle valve for controlling the feed speed of the hob, and the rotating unit integrates a second throttle valve for controlling the rotation speed of the hob.

Images