Device for indirectly measuring pressure of blast hole wall under impact

Abstract

The invention relates to the technical field of engineering blasting, and discloses a blast hole wall impact pressure indirect measurement device, which comprises an external fixed steel pipe, a blast hole wall is arranged in the external fixed steel pipe, a blocking material is arranged at the opening end of the external fixed steel pipe, and the external fixed steel pipe is used for transmitting and attenuating the explosion pressure borne by the blast hole wall; the energy source is arranged in an inner cavity of the external fixed steel pipe, and the energy source is an explosive cartridge or a liquefied air energy storage pipe; the detonating equipment comprises an electronic detonator and an electric lead, the electronic detonator is pre-buried in the explosive cartridge or the liquefied air energy storage tube, and the electronic detonator is connected with an external exploder through the electric lead; the strain gauges are fixedly connected to the outer wall of the external fixing steel pipe, and a pressure testing system is arranged outside the external fixing steel pipe. According to the invention, the strain gauges are fixed on the outer wall of the external fixed steel pipe, and the steel pipe is used as a medium for pressure transmission and attenuation, so that the impact pressure generated by explosion is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of engineering blasting technology, specifically to an indirect pressure measuring device for the borehole wall under impact. Background Technology

[0002] In rock blasting engineering, borehole wall pressure is a core indicator for measuring blasting effectiveness. It directly reflects the efficiency of blasting energy transfer and utilization, and is a key parameter for evaluating the rationality of blasting parameters, predicting rock-breaking effects, and controlling the range of rock mass damage. Accurate acquisition of this parameter is of paramount importance for optimizing blasting parameter design, ensuring the safety of the construction process, and achieving effective cost control.

[0003] Current conventional techniques typically involve mounting pressure sensors directly on the borehole wall to capture pressure data from the blast impact in real time. In traditional explosive blasting scenarios, specialized high-strength pressure sensors are used. However, in emerging liquefied air energy storage rock-breaking technology, sensors adapted to ultra-low temperature environments are employed for measurement.

[0004] However, existing measurement technologies, in traditional explosive blasting scenarios, generate extremely high instantaneous temperatures and pressures upon detonation. Pressure sensors placed on the borehole wall are highly susceptible to failure or physical damage due to the high-temperature, high-pressure impact, making effective data acquisition difficult. Furthermore, for liquefied air energy storage rock-breaking technology, the energy storage tube must be in an ultra-low temperature state before activation. Prolonged exposure to ultra-low temperatures reduces the activity of the sensor's internal electronic components, causing it to cease operation before rock-breaking begins. Therefore, this invention provides an indirect pressure measurement device for borehole walls under impact, addressing the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an indirect pressure measurement device for borehole walls under impact, which solves the problem in existing technologies where sensor damage due to extreme high-temperature, high-pressure, or low-temperature environments makes it difficult to accurately and stably measure the dynamic pressure of borehole walls.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an indirect pressure measuring device for a borehole wall under impact, comprising:

[0007] An externally fixed steel pipe is provided, with a borehole wall inside the externally fixed steel pipe and a plugging material at the open end of the externally fixed steel pipe. The externally fixed steel pipe is used to transmit and attenuate the explosion pressure on the borehole wall.

[0008] An energy source is provided in the inner cavity of an externally fixed steel pipe, and the energy source is an explosive cartridge or a liquefied air storage pipe.

[0009] The detonation device includes an electronic detonator and an electrical wire. The electronic detonator is pre-embedded inside the explosive cartridge or liquefied air storage tube, and the electronic detonator is connected to an external detonator via the electrical wire.

[0010] Multiple strain gauges are fixedly connected to the outer wall of an externally fixed steel pipe. A pressure testing system is installed outside the externally fixed steel pipe, and the strain gauges are electrically connected to the pressure testing system through multiple wires.

[0011] Preferably, the strain gauges are distributed in a grid pattern on the outer wall surface of the externally fixed steel pipe, and the strain gauges cover measuring points at different depths along the axial direction and at different orientations along the circumference of the externally fixed steel pipe.

[0012] Preferably, the plugging material is selected from stemming clay.

[0013] Preferably, the externally fixed steel pipe has a uniform wall thickness and an inner diameter that is compatible with the diameter of the explosive cartridge or liquefied air storage pipe. The bottom of the externally fixed steel pipe is welded to a bracket and fixed to the ground.

[0014] Preferably, the pressure testing system includes:

[0015] The signal acquisition module is used to receive the strain signal of the strain gauge and construct the received strain signal into a raw data stream containing timing information.

[0016] The data processing unit is used to receive the constructed raw data stream and convert the strain values ​​in the raw data stream into dynamic pressure values ​​according to the pre-established pressure-strain conversion relationship model.

[0017] The data storage module is used to construct historical pressure curves based on dynamic pressure values ​​and store the constructed historical pressure curves and the original data stream;

[0018] The display module is used to generate and display real-time pressure curves based on dynamic pressure values ​​for human-computer interaction.

[0019] Preferably, the data processing unit is specifically used for:

[0020] The raw data stream is received, and the strain value is parsed out through a data parsing algorithm. Based on the known elastic modulus and strain value of the externally fixed steel pipe, the stress value of the outer wall of the externally fixed steel pipe is constructed.

[0021] Based on the geometric parameters of the externally fixed steel pipe and the stress value of the outer wall of the externally fixed steel pipe, the pressure value of the inner wall of the externally fixed steel pipe is constructed.

[0022] Based on the pre-established pressure-strain calculation model, the pressure value of the inner wall of the externally fixed steel pipe is corrected to generate a dynamic pressure value.

[0023] Preferably, the conversion of strain values ​​in the original data stream into dynamic pressure values ​​uses the following formula:

[0024] ;

[0025] ;

[0026] ;

[0027] In the formula, , These are the outer and inner diameters of the externally fixed steel pipe, respectively. and The circumferential strain and stress of the outer wall of the externally fixed steel pipe are given. The elastic modulus of the externally fixed steel pipe is given. and The pressure on the inner wall of the externally fixed steel pipe and the corrected dynamic pressure. This is a dynamic correction coefficient.

[0028] Preferably, the data processing unit can also be used to construct the real-time monitoring status of the strain gauge to monitor the signal acquisition status; and to generate abnormal alarm information when the pressure value exceeds a preset safety range based on the dynamic pressure value. The data storage module can use a non-volatile storage medium to store historical pressure curves and raw data streams for a long time. The display module can be used to generate and display real-time pressure curves, peak pressure and average pressure parameters, and a list of pressure values ​​changing over time.

[0029] This invention provides an indirect pressure measurement device for the borehole wall under impact. It has the following advantages:

[0030] 1. This invention significantly reduces the impact pressure generated by an explosion by fixing strain gauges to the outer wall of an externally mounted steel pipe and using the steel pipe as a medium for pressure transmission and attenuation. This indirect measurement method effectively avoids direct damage to sensitive sensors in extreme high-temperature, high-pressure, or ultra-low-temperature environments, solving the problem of sensor failure in existing technologies.

[0031] 2. The data processing unit of this invention, based on a pre-established pressure-strain conversion model, can accurately convert the raw strain data collected by strain gauges into the dynamic pressure value borne by the borehole wall. This model considers the mechanical parameters and geometric dimensions of the steel pipe material and has been corrected through laboratory calibration, ensuring the objectivity and reliability of the conversion results.

[0032] 3. By arranging multiple strain gauges in a grid pattern on the outer wall of an externally fixed steel pipe, this invention can simultaneously collect strain data at different depths along the axial direction and at different circumferential positions of the borehole. This allows the data processing unit to calculate the pressure distribution information at multiple points, providing an effective technical means for in-depth analysis and research on the spatiotemporal distribution of the dynamic pressure field inside the borehole during blasting. Attached Figure Description

[0033] Figure 1 This is a perspective view of the present invention;

[0034] Figure 2 This is an axial half-section structural diagram of the gun borehole wall pressure measuring device of the present invention;

[0035] Figure 3 This is an axial half-section structural diagram of the liquefied air energy storage pipe wall pressure measuring device of the present invention;

[0036] Figure 4 This is a schematic diagram of the propagation of explosion stress wave in the cross section of the device of the present invention;

[0037] Figure 5 This is a diagram of the pressure testing system architecture of the present invention;

[0038] Figure 6 This is a dynamic pressure-time curve diagram of the present invention.

[0039] Among them, 1. strain gauge; 2. external fixed steel pipe; 3. plugging material; 4. electrical wire; 5. borehole wall; 6. electronic detonator; 7. explosive cartridge; 8. liquefied air storage tube. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see the appendix Figure 1 - Appendix Figure 4 This invention provides an indirect pressure measurement device for borehole walls under impact, comprising:

[0042] An externally fixed steel pipe 2 has a borehole wall 5 inside. A plugging material 3 is installed at the open end of the externally fixed steel pipe 2. The externally fixed steel pipe 2 is used to transmit and attenuate the explosion pressure on the borehole wall 5. The steel pipe has a uniform wall thickness, and its elastic modulus and Poisson's ratio are calibrated and known. The externally fixed steel pipe 2 acts as a medium for transmitting and attenuating the explosion stress wave, reducing the high-intensity shock wave pressure to a measurable range, while simultaneously providing confinement for the internal energy source.

[0043] The energy source is located inside the outer fixed steel pipe 2. The energy source is either an explosive cartridge 7 or a liquefied air storage pipe 8. The energy source is the main body that generates the explosive impact force. Its size is adapted to the inner diameter of the outer fixed steel pipe 2 to ensure that it can be completely filled and constrained inside the outer fixed steel pipe 2 to provide a uniform and stable pressure load.

[0044] The detonation device includes an electronic detonator 6 and a wire 4. The electronic detonator 6 is pre-embedded inside the explosive cartridge 7 or the liquefied air storage tube 8. The electronic detonator 6 is connected to an external detonator via the wire 4. This detonation device is used to remotely and safely detonate the energy source and is the control unit that triggers the entire measurement process. Its wire 4 passes through the blocking material 3 to ensure the integrity of the detonation circuit and the airtightness of the device.

[0045] Multiple strain gauges 1 are fixedly connected to the outer wall of an externally fixed steel pipe 2. A pressure testing system is installed outside the externally fixed steel pipe 2, and the strain gauges 1 are electrically connected to the pressure testing system via multiple wires. The strain gauges 1 are the core sensing elements, capturing the minute deformation of the outer wall of the externally fixed steel pipe 2 under stress and converting it into electrical signals, providing raw data for subsequent data processing and pressure calculation. The strain gauges 1 are arranged in a grid pattern to obtain strain information at multiple points.

[0046] Please see the appendix Figure 1 - Appendix Figure 3Strain gauges 1 are arranged in a grid pattern on the outer wall of the externally fixed steel pipe 2, covering measuring points at different depths along the axial direction and at different orientations along the circumference. This grid-based arrangement allows for multi-point, multi-dimensional strain information acquisition, comprehensively capturing the spatiotemporal distribution characteristics of the explosion stress wave on the externally fixed steel pipe 2, providing a data foundation for subsequent precise analysis of the pressure field. The plugging material 3 is selected from stemming clay. This plugging material 3 forms an effective sealing section inside the externally fixed steel pipe 2, ensuring that the impact pressure generated by the explosion can fully act on the borehole wall 5, while preventing the explosion energy from escaping from the open end, ensuring the stability and safety of the measurement process. The externally fixed steel pipe 2 has a uniform wall thickness, and its inner diameter is adapted to the diameter of the explosive cartridge 7 or the liquefied air storage pipe 8. A welded bracket at the bottom of the externally fixed steel pipe 2 is fixed to the ground. The uniform wall thickness of the externally fixed steel pipe 2 ensures consistent attenuation and transmission of stress waves on the pipe body, thereby guaranteeing the accuracy of strain-pressure conversion. The welded bracket at the bottom of the external fixed steel pipe 2 provides a stable installation foundation, preventing the device from shifting or overturning at the moment of explosion, thus ensuring the stability of the test process.

[0047] Please see the appendix Figure 1 - Appendix Figure 6 The stress testing system includes a signal acquisition module, a data processing unit, a data storage module, and a display module.

[0048] The signal acquisition module is used to receive the strain signal from strain gauge 1 and construct the received strain signal into a raw data stream containing timing information.

[0049] The data processing unit receives the raw data stream and converts the strain values ​​in the raw data stream into dynamic pressure values ​​based on a pre-established pressure-strain conversion model.

[0050] The data storage module is used to construct historical pressure curves based on dynamic pressure values ​​and to store the constructed historical pressure curves and the original data stream.

[0051] The display module is used to generate and display real-time pressure curves based on dynamic pressure values ​​to enable human-computer interaction.

[0052] The specific workflow of the data processing unit is as follows: First, the raw data stream is parsed using a data parsing algorithm to extract strain values. The data processing unit is based on the known elastic modulus of the externally fixed steel pipe 2. and the collected circumferential strain values Construct the circumferential stress value of the outer wall of the externally fixed steel pipe 2 Stress value With circumferential strain value The relationship between them follows Hooke's Law and can be expressed by the following formula:

[0053] ;

[0054] In the formula, The elastic modulus of the externally fixed steel pipe 2, The circumferential strain of the outer wall of the externally fixed steel pipe 2 is given.

[0055] Secondly, the data processing unit is based on the geometric parameters of the externally fixed steel pipe 2 and the circumferential stress value of the constructed outer wall. , Construct the pressure value of the inner wall of the externally fixed steel pipe 2 According to the theory of thick-walled cylinders, the pressure value on the inner wall... Circumferential stress of the outer wall The relationship between them can be expressed by the following formula:

[0056] ;

[0057] In the formula, The outer diameter of the externally fixed steel pipe, The inner diameter of the externally fixed steel pipe.

[0058] Finally, the data processing unit calculates the pressure value of the inner wall of the external fixed steel pipe 2 based on the pre-established pressure-strain calculation model. Dynamic correction is performed to generate dynamic pressure values. Corrected dynamic pressure value With inner wall pressure value The relationship between them is:

[0059] ;

[0060] In the formula, The corrected dynamic pressure value. This is a dynamic correction factor, which is obtained through laboratory calibration.

[0061] The data processing unit is also used to construct the real-time monitoring status of strain gauge 1 to monitor the signal acquisition status; and to generate abnormal alarm information when the pressure value exceeds the preset safety range based on the dynamic pressure value. The data storage module uses non-volatile storage media to store historical pressure curves and raw data streams for a long time. The display module is specifically used to generate and display real-time pressure curves, peak pressure and average pressure parameters, and a list of pressure values ​​changing over time.

[0062] Working principle: Before the test begins, the explosive cartridge 7 or liquefied air storage tube 8 is first filled into the inner cavity of the external fixed steel pipe 2, and the open end is sealed with plugging material 3. The electronic detonator 6 is pre-embedded inside the energy source, and the wire 4 is passed out from the plugging section and connected to the external detonator. At the same time, multiple strain gauges 1 are fixed to the outer wall of the external fixed steel pipe 2 and electrically connected to the pressure test system through wires. The pipe is then fixed to the ground by welding brackets.

[0063] During the test, the external detonator remotely detonates the electronic detonator 6, which in turn detonates the energy source. The huge impact pressure generated by the explosion inside the borehole wall 5 is transmitted through the external fixed steel pipe 2, forming a radial stress wave. This stress wave is damped and attenuated as it passes through the external fixed steel pipe 2, and its energy is significantly reduced. When the attenuated stress wave is transmitted to the outer wall of the steel pipe, it causes the pipe wall to produce small circumferential and axial strains.

[0064] Strain gauge 1 captures minute strain on the outer wall of the externally fixed steel pipe 2 in real time and converts it into an electrical signal. The electrical signal is then transmitted to the signal acquisition module of the pressure testing system, which constructs the strain signal into a raw data stream containing timing information and sends it to the data processing unit.

[0065] The data processing unit uses the collected strain values ​​and Hooke's Law to calculate the stress value on the outer wall of the externally fixed steel pipe 2. Based on the thick-walled cylinder theory, it constructs the theoretical pressure value borne by the inner wall of the externally fixed steel pipe 2 using the outer wall stress value and the inner and outer diameter parameters of the externally fixed steel pipe 2. For the explosion process, the data processing unit introduces a dynamic correction coefficient to correct the theoretical pressure value, thereby obtaining a dynamic pressure value that conforms to the actual situation. The data storage module stores the generated dynamic pressure values ​​and constructs historical pressure curves. The display module generates and displays real-time pressure curves, peak pressure, and average pressure based on the dynamic pressure values, realizing intuitive monitoring of pressure changes inside the borehole.

[0066] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for indirectly measuring the pressure on the borehole wall under impact, characterized in that, include: An externally fixed steel pipe (2) is provided with a borehole wall (5) inside the externally fixed steel pipe (2), and a plugging material (3) is provided at the open end of the externally fixed steel pipe (2). The externally fixed steel pipe (2) is used to transmit and attenuate the explosion pressure on the borehole wall (5). The energy source is located in the inner cavity of the externally fixed steel pipe (2), and the energy source is an explosive cartridge (7) or a liquefied air storage pipe (8). The detonation device includes an electronic detonator (6) and an electrical wire (4). The electronic detonator (6) is embedded inside an explosive cartridge (7) or a liquefied air storage tube (8). The electronic detonator (6) is connected to an external detonator via the electrical wire (4). Multiple strain gauges (1) are fixedly connected to the outer wall of an external fixed steel pipe (2). A pressure testing system is installed outside the external fixed steel pipe (2). The strain gauges (1) are electrically connected to the pressure testing system through multiple wires.

2. The indirect pressure measuring device for a borehole wall under impact as described in claim 1, characterized in that, The strain gauges (1) are distributed in a grid pattern on the outer wall of the external fixed steel pipe (2), and the strain gauges (1) cover the measuring points of the external fixed steel pipe (2) at different depths along the axial direction and at different positions along the circumference.

3. The indirect pressure measuring device for a borehole wall under impact as described in claim 1, characterized in that, The plugging material (3) is selected from potting clay.

4. The indirect pressure measuring device for a borehole wall under impact as described in claim 1, characterized in that, The external fixed steel pipe (2) has a uniform wall thickness and an inner diameter that is compatible with the diameter of the explosive cartridge (7) or the liquefied air storage pipe (8). The bottom of the external fixed steel pipe (2) is welded to a bracket and fixed to the ground.

5. The indirect pressure measuring device for a borehole wall under impact as described in claim 1, characterized in that, The stress testing system includes: The signal acquisition module is used to receive the strain signal of the strain gauge (1) and construct the received strain signal into a raw data stream containing timing information; The data processing unit is used to receive the constructed raw data stream and convert the strain values ​​in the raw data stream into dynamic pressure values ​​according to the pre-established pressure-strain conversion relationship model. The data storage module is used to construct historical pressure curves based on dynamic pressure values ​​and store the constructed historical pressure curves and the original data stream; The display module is used to generate and display real-time pressure curves based on dynamic pressure values ​​for human-computer interaction.

6. The indirect pressure measuring device for a borehole wall under impact as described in claim 5, characterized in that, The data processing unit is specifically used for: The raw data stream is received, and the strain value is parsed out through the data parsing algorithm. Based on the known elastic modulus and strain value of the external fixed steel pipe (2), the stress value of the outer wall of the external fixed steel pipe (2) is constructed. Based on the geometric parameters of the external fixed steel pipe (2) and the stress value of the outer wall of the external fixed steel pipe (2), the pressure value of the inner wall of the external fixed steel pipe (2) is constructed. Based on the pre-established pressure-strain calculation model, the pressure value of the inner wall of the external fixed steel pipe (2) is corrected to generate a dynamic pressure value.

7. The indirect pressure measuring device for a borehole wall under impact as described in claim 5, characterized in that, The following formula is used to convert the strain values ​​in the original data stream into dynamic pressure values: ； ； ； in, , These are the outer diameter and inner diameter of the externally fixed steel pipe (2), respectively. and The circumferential strain and stress of the outer wall of the externally fixed steel pipe (2) are given. The elastic modulus of the externally fixed steel pipe (2) is given by [the relevant parameter]. and The pressure on the inner wall of the externally fixed steel pipe (2) and the corrected dynamic pressure, This is a dynamic correction coefficient.

8. The indirect pressure measuring device for a borehole wall under impact as described in claim 5, characterized in that, The data processing unit is also used for: The real-time monitoring status of the strain gauge (1) is constructed to monitor the signal acquisition status; Based on dynamic pressure values, abnormal alarm information is generated when the pressure value exceeds the preset safety range.

9. The indirect pressure measuring device for a borehole wall under impact according to claim 5, characterized in that, The data storage module uses a non-volatile storage medium to store historical pressure curves and raw data streams for a long time.

10. The indirect pressure measuring device for a borehole wall under impact according to claim 5, characterized in that, The display module is specifically used to generate and display real-time pressure curves, peak pressure and average pressure parameters, and a list of pressure values ​​that change over time.

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