阅读说明：本技术 围压控制系统及其控制方法 (Confining pressure control system and control method thereof ) 是由 张泽天 谢和平 张茹 陈领 高明忠 张志龙 李怡航 杨阳 李佳南 黄伟 任利 于 2021-01-15 设计创作，主要内容包括：本发明公开了围压控制系统及其控制方法,通过产生压力将高压油送入油缸,同时对压力进行测量,在压力不足时可通过蓄能器释放能量维持压力,实现了压力的产生与测量,适用于岩样的围压模拟实验。本发明构建了压力测量仪的电路,通过采用型号为PTH702H的压力传感器,从而实现高压力测量,并且设置有显示屏,可以实用显示压力。本发明设置有无线通讯电路,可以将数据传输至其他设备。本发明能够持续产生高压油,将高压油送入油缸以对岩样施加压力,模拟其地下高压的环境,实现了对岩样的围压测量。(The invention discloses a confining pressure control system and a control method thereof. The pressure measuring instrument circuit is constructed, the pressure sensor with the model of PTH702H is adopted, high pressure measurement is achieved, and the pressure measuring instrument circuit is provided with the display screen and can display pressure practically. The wireless communication circuit is arranged, and data can be transmitted to other equipment. The invention can continuously generate high-pressure oil, and the high-pressure oil is sent into the oil cylinder to apply pressure to the rock sample, so that the underground high-pressure environment is simulated, and the confining pressure measurement of the rock sample is realized.)

1. A confining pressure control system is characterized by comprising a hydraulic pump (1), wherein the hydraulic pump (1) is connected with an external oil tank and is connected to one end P of a first pipeline in an electromagnetic directional valve (2) and the input end of an overflow valve (3), the output end of the overflow valve (3) is connected to the oil tank, the other end A of the first pipeline in the electromagnetic directional valve (2) is respectively connected with a liquid inlet of a first hydraulic control one-way valve (6), one end of a pipeline of a booster directional valve (4) and a liquid inlet of a second hydraulic control one-way valve (7), a liquid outlet of the second hydraulic control one-way valve (7) is connected to an oil cylinder (11), a connecting pipeline of the second hydraulic control one-way valve (7) and the oil cylinder (11) is provided with an energy accumulator (9) and a pressure measuring instrument (10), a liquid outlet of the first hydraulic control one-way valve (6) is respectively connected with a liquid inlet of a third one-way valve (8) and the, the bottom of pressure cylinder (5) is connected with the pipeline other end of booster switching-over valve (4), the middle part of pressure cylinder (5) is connected to the case of booster switching-over valve (4) and the inlet of fourth liquid accuse check valve (12), the liquid outlet of fourth liquid accuse check valve (12) is connected with the one end B of second pipeline in electromagnetic directional valve (2), the other end T of second pipeline is connected to outside oil tank in electromagnetic directional valve (2), the liquid outlet of third liquid accuse check valve (8) is connected to hydro-cylinder (11).

2. The confining pressure control system according to claim 1, characterized in that the pressure measuring instrument (10) comprises a pressure sensor U4, an AD conversion module, a single chip microcomputer module, a display module and a wireless communication module, wherein the pressure sensor is connected with the AD conversion module, and the single chip microcomputer module is respectively connected with the AD conversion module, the display module and the wireless communication module.

3. The confining pressure control system as claimed in claim 1, wherein the pressure sensor U4 is of the type PTH702H, and the 1 st pin of the pressure sensor U4 is connected to +24V voltage.

4. The confining pressure control system according to claim 3, wherein the AD conversion module comprises an AD conversion chip U3 with model number TCL549CD, a REF + pin and a VCC pin of the AD conversion chip U3 are both connected with +5V voltage, a REF-pin and a GND pin of the AD conversion chip U3 are grounded, and an ANLGIN pin of the AD conversion chip U3 is connected with a 3 rd pin of a pressure sensor U4.

5. The confining pressure control system according to claim 4, characterized in that the single chip microcomputer module comprises a single chip microcomputer U1 with a model number of AT89S51, an XTAL1 pin of the single chip microcomputer U1 is connected with one end of a crystal oscillator X1 and a grounding capacitor C2 respectively, an XTAL2 pin of the single chip microcomputer U1 is connected with a crystal oscillator X1 and a grounding capacitor C3 respectively, a RST pin of the single chip microcomputer U1 is connected with one end of a resistor R1, a grounding capacitor C1 and a grounding switch K1 respectively, the other end of the resistor R1 is connected with a voltage of +5V, a P1.0 pin of the single chip microcomputer U1 is connected with a CLK pin of an AD conversion chip U3, a P1.1 pin of the single chip microcomputer U1 is connected with a pin of a DO AD conversion chip U3, and a P1.2 pin of the single chip microcomputer U1 is connected with a CS pin of an AD conversion chip 67U 3.

6. The confining pressure control system according to claim 4, wherein the display module comprises a display screen LCD1 model LM1602, the VSS pin of the display screen LCD1 is connected to +5V, the VDD pin of the display screen LCD1 is connected to ground, the VEE pin of the display screen LCD1 is connected with the sliding end of a sliding resistor RV1, the first fixed end of the sliding resistor RV1 is grounded, the second fixed end of the sliding resistor RV1 is connected with +5V voltage, the RS pin, the RW pin and the E pin of the display screen LCD1 are correspondingly connected with the P2.0 pin, the P2.1 pin and the P2.2 pin of the singlechip U1, the pins D0 to D7 of the display screen LCD1 are respectively connected with the pins 2 to 9 of the resistor RP1 in a one-to-one correspondence manner, the 2 nd pin to the 9 th pin of the resistor pack RP1 are respectively connected with the pins P0.0 to P0.7 of the singlechip in a one-to-one correspondence manner, and the 1 st pin of the resistor pack RP1 is connected with +5V voltage.

7. The confining pressure control system according to claim 6, wherein the wireless communication module includes a wireless communication integrated board U2 with model number NRF24L01+, CE pins, CSN pins, SCK pins, MOSI pins, MISO pins and IRQ pins of the wireless communication integrated board U2 are respectively connected with P3.0 to P3.5 of the single chip microcomputer U1 in a one-to-one correspondence manner, VCC pins of the wireless communication integrated board U2 are connected with +3.3V voltage, and GND pins of the wireless communication integrated board U2 are grounded.

8. A confining pressure control method using the confining pressure control system as claimed in any one of claims 1-7, characterized by comprising the steps of:

s1, placing the rock sample into the oil cylinder, using a PLC (programmable logic controller) as a controller of the confining pressure control system, and enabling the conduction direction of the electromagnetic directional valve (2) to be the initial conduction direction from the hydraulic pump (1) to the second hydraulic control one-way valve (7) and the booster directional valve (4) to be the initial conduction direction from the booster cylinder (5) to the electromagnetic directional valve (2);

s2, controlling the hydraulic pump (1) to work through the PLC, pumping oil in an external oil tank to the electromagnetic directional valve (2), and enabling the oil to reach the oil tank (11) through the second hydraulic control one-way valve (7), the energy accumulator (9) and the pressure measuring instrument (10) in sequence;

s3, judging whether the second hydraulic control one-way valve (7) is automatically closed or not, if so, entering a step S4, otherwise, continuously judging until the second hydraulic control one-way valve (7) is automatically closed, and entering a step S4;

s4, pumping oil in an external oil tank to the electromagnetic directional valve (2), enabling the oil to enter a top piston HP in the pressure cylinder (5) through the first hydraulic control one-way valve (6), and pushing the top piston HP and a bottom piston LP to the bottom of the pressure cylinder (5);

s5, driving a valve core of a supercharger reversing valve (4) to move downwards to the supercharger reversing valve (4) for reversing through oil, enabling the oil to reach the bottom of a supercharging cylinder (5) from an electromagnetic reversing valve (2), pushing a top piston HP and a bottom piston LP to move upwards, and outputting high-pressure oil;

and S6, enabling the high-pressure oil to sequentially pass through the third hydraulic control one-way valve (8), the energy accumulator (9) and the pressure measuring instrument (10) to reach the oil cylinder (11), measuring confining pressure in real time through the pressure measuring instrument (10), adjusting the pressure in real time according to a confining pressure measuring result, and finishing confining pressure control applied to the fidelity cabin.

9. The confining pressure control method according to claim 8, characterized in that during the confining pressure measurement, energy is stored by the energy accumulator (9), and when the pressure measured by the pressure measuring instrument (10) is smaller than a set threshold value, the energy of the energy accumulator (9) is released to ensure that the pressure does not drop;

after confining pressure measurement is finished, the hydraulic pump (1) is closed, the conducting direction of the electromagnetic directional valve (2) is from the second hydraulic control one-way valve (7) to the hydraulic pump (1), the fourth hydraulic control one-way valve (12) is conducted, and residual oil in the system sequentially flows back to an external oil tank through the fourth hydraulic control one-way valve (12) and the electromagnetic directional valve (2).

Technical Field

The invention belongs to the fields of geology and power electronics, and particularly relates to a confining pressure control system and a confining pressure control method.

Background

Rock mass in the stratum, especially natural rock mass in deep rock stratum, is affected by factors such as gravity, plate motion and shrinkage of earth crust, so that the internal stress level of the rock mass is high, and the phenomenon of high ground stress is presented. The stress environment (a laboratory usually uses confining pressure to simulate) where the rock mass is located directly influences the physical and mechanical properties of the rock, the rock breaking/destroying mechanism and the like, and influences the rock breaking load characteristic, the rock breaking efficiency, the service life and the like of the excavation device; therefore, the simulation of the natural stress environment and its influence must be considered when conducting rock mechanics behavior tests in the laboratory. The rock mass has completely different characteristics under the condition of uniaxial stress (namely, a laboratory non-confining pressure test environment) from the characteristics of natural rock mass under the conditions of high confining pressure of deep stratum and low confining pressure stress in superficial stratum, and the mechanical characteristics of the rock mass under the in-situ stress environment are one of necessary information for the stability analysis and engineering design of large-scale underground caverns, and are particularly important for the safety evaluation and disaster prevention and control of deep high-stress underground engineering. Therefore, when studying the rock mechanics and geotechnical engineering problems closely related to the rock stress, especially when relating to the research fields of deep rock formations such as the rock breaking mechanism of a TBM (hard rock tunneling machine) tunneling cutter under a large buried depth tunnel environment, the coal rock excavation mechanism of a cutting head of an anchor driving machine under a deep coal roadway, the drilling and blasting method construction of local geological structure high stress special deep engineering, and the like, the rock mass confining pressure effect needs to be considered in the research process, and the real state of the rock mass confining pressure needs to be simulated in the corresponding test.

Referring to the confining pressure simulation principle of the present two-axis rock physical and mechanical properties testing machine, in theory, a pair of hydraulic cylinder opposite vertex mode can be adopted to apply lateral confining pressure to the rock sample block, but auxiliary equipment such as a hydraulic pump station and a high-precision servo oil cylinder need to be additionally purchased, so that the confining pressure simulation device has the limitations of complex structure, high cost and difficulty in maintenance, and many confining pressure simulation devices do not have confining pressure measuring mechanisms and cannot reflect the confining pressure size in real time.

Disclosure of Invention

Aiming at the defects in the prior art, the confining pressure control system and the control method thereof provided by the invention realize a simulation experiment of a deep high-ground stress environment, measure confining pressure by using the electronic sensor, and regulate and control confining pressure based on the measured confining pressure, thereby solving the problems of complex structure and high cost of the confining pressure control system in the prior art.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that: a confining pressure control system comprises a hydraulic pump, wherein the hydraulic pump is connected with an external oil tank and is connected to one end P of a first pipeline in an electromagnetic directional valve and the input end of an overflow valve, the output end of the overflow valve is connected to the oil tank, the other end A of the first pipeline in the electromagnetic directional valve is respectively connected with a liquid inlet of a first hydraulic control one-way valve, one end of a pipeline of a booster directional valve and a liquid inlet of a second hydraulic control one-way valve, a liquid outlet of the second hydraulic control one-way valve is connected to an oil cylinder, an energy accumulator and a pressure measuring instrument are arranged on a connecting pipeline of the second hydraulic control one-way valve and the oil cylinder, a liquid outlet of the first hydraulic control one-way valve is respectively connected with a liquid inlet of a third hydraulic control one-way valve and the top of a booster cylinder, the bottom of the booster cylinder is connected with the other end of the pipeline of the booster directional, and a liquid outlet of the fourth hydraulic control one-way valve is connected with one end B of a second pipeline in the electromagnetic directional valve, the other end T of the second pipeline in the electromagnetic directional valve is connected to an external oil tank, and a liquid outlet of the third hydraulic control one-way valve is connected to the oil cylinder.

Further, pressure measurement appearance includes pressure sensor U4, AD conversion module, single chip module, display module and wireless communication module, pressure sensor is connected with AD conversion module, single chip module is connected with AD conversion module, display module and wireless communication module respectively.

Further, the pressure sensor U4 is of the type PTH702H, and the 1 st pin of the pressure sensor U4 is connected to + 24V.

Further, the AD conversion module comprises an AD conversion chip U3 with the model number of TCL549CD, a REF + pin and a VCC pin of the AD conversion chip U3 are both connected with +5V voltage, a REF-pin and a GND pin of the AD conversion chip U3 are grounded, and an ANLGIN pin of the AD conversion chip U3 is connected with a No. 3 pin of the pressure sensor U4.

Further, the single chip microcomputer module comprises a single chip microcomputer U1 with the model number of AT89S51, an XTAL1 pin of the single chip microcomputer U1 is connected with one end of a crystal oscillator X1 and a grounding capacitor C2, an XTAL2 pin of the single chip microcomputer U1 is connected with the crystal oscillator X1 and a grounding capacitor C3, an RST pin of the single chip microcomputer U1 is connected with one end of a resistor R1, the grounding capacitor C1 and a grounding switch K1, the other end of the resistor R1 is adjacent to +5V voltage, a P1.0 pin of the single chip microcomputer U1 is connected with a CLK pin of an AD conversion chip U3, a P1.1 pin of the single chip microcomputer U1 is connected with a DO pin of an AD conversion chip U3, and a P1.2 pin of the single chip U1 is connected with a CS pin of the AD conversion chip U3.

Further, the display module comprises a display screen LCD1 with a model number of LM1602, a VSS pin of the display screen LCD1 is connected with a +5V voltage, a VDD pin of the display screen LCD1 is grounded, a VEE pin of the display screen LCD1 is connected with a sliding end of a sliding resistor RV1, a first fixed end of the sliding resistor RV1 is grounded, a second fixed end of the sliding resistor RV1 is connected with the +5V voltage, an RS pin, a RW pin and an E pin of the display screen LCD1 are correspondingly connected with a P2.0 pin, a P2.1 pin and a P2.2 pin of a singlechip U1, pins D0 to D7 of the display screen LCD1 are correspondingly connected with a pin 2 to a pin 9 of the exclusion RP1, a pin 2 to a pin 9 of the exclusion RP1 are correspondingly connected with a pin P0.0 to a pin P0.7 one by one, and a pin 1 of the exclusion RP1 is connected with a voltage +5V voltage.

Further, the wireless communication module comprises a wireless communication integrated board U2 with the model of NRF24L01+, a CE pin, a CSN pin, an SCK pin, an MOSI pin, a MISO pin and an IRQ pin of the wireless communication integrated board U2 are respectively connected with P3.0 to P3.5 of the single chip microcomputer U1 in a one-to-one correspondence manner, a VCC pin of the wireless communication integrated board U2 is connected with +3.3V voltage, and a GND pin of the wireless communication integrated board U2 is grounded.

The invention has the beneficial effects that:

(1) the confining pressure control system is constructed, high-pressure oil can be fed into the oil cylinder by generating pressure, so that the oil cylinder has higher pressure, the pressure is measured, and energy can be released by the energy accumulator when the pressure is insufficient, so that the high pressure is maintained.

(2) The pressure measuring instrument circuit is constructed, the pressure sensor with the model of PTH702H is adopted, high pressure measurement is achieved, and the pressure measuring instrument circuit is provided with the display screen and can display pressure practically.

(3) The wireless communication circuit is arranged, and data can be transmitted to other equipment.

(4) The hydraulic pump can continuously generate high-pressure fluid to act on a sample to generate high pressure, so that the simulation of a deep in-situ high-pressure environment is realized.

A confining pressure control method comprises the following steps:

s1, placing the rock sample into an oil cylinder, using a PLC (programmable logic controller) as a controller of the confining pressure control system, and enabling the conduction direction of an electromagnetic directional valve to be from a hydraulic pump to a second hydraulic control one-way valve and the initial conduction direction of a booster directional valve to be from a booster cylinder to the electromagnetic directional valve;

s2, controlling the hydraulic pump to work through the PLC, pumping oil in the external oil tank to the electromagnetic directional valve, and enabling the oil to reach the oil cylinder through the second hydraulic control one-way valve, the energy accumulator and the pressure measuring instrument in sequence;

s3, judging whether the second hydraulic control one-way valve is automatically closed, if so, entering the step S4, otherwise, continuing judging until the second hydraulic control one-way valve is automatically closed, and entering the step S4;

s4, pumping oil in an external oil tank to an electromagnetic directional valve, enabling the oil to enter a top piston HP in the pressure cylinder through a first hydraulic control one-way valve, and pushing the top piston HP and a bottom piston LP to the bottom of the pressure cylinder;

s5, driving a valve core of the supercharger reversing valve to move downwards to the supercharger reversing valve for reversing through oil, enabling the oil to reach the bottom of the supercharger cylinder from the electromagnetic reversing valve, pushing the top piston HP and the bottom piston LP to move upwards, and outputting high-pressure oil;

and S6, enabling the high-pressure oil to sequentially pass through the third hydraulic control one-way valve, the energy accumulator and the pressure measuring instrument to reach the oil cylinder, measuring confining pressure in real time through the pressure measuring instrument, adjusting the pressure in real time according to a confining pressure measuring result, and finishing confining pressure control applied to the fidelity cabin.

Furthermore, during the confining pressure measurement, energy is stored through the energy accumulator, and when the pressure measured by the pressure measuring instrument is smaller than a set threshold value, the energy of the energy accumulator is released to ensure that the pressure cannot be reduced;

and after confining pressure measurement is finished, the hydraulic pump is closed, the conduction direction of the electromagnetic directional valve is from the second hydraulic control one-way valve to the hydraulic pump, the fourth hydraulic control one-way valve is conducted, and residual oil in the system sequentially flows back to the external oil tank through the fourth hydraulic control one-way valve and the electromagnetic directional valve.

The invention has the beneficial effects that:

(1) the invention can continuously generate high-pressure oil, and the high-pressure oil is sent into the oil cylinder to apply pressure to the rock sample, so that the underground high-pressure environment is simulated, and the confining pressure measurement of the rock sample is realized.

(2) After the confining pressure measurement is finished, residual oil in the pressurization system can flow back to the external oil tank.

Drawings

Fig. 1 is a schematic view of a confining pressure control system according to the present invention.

Fig. 2 is a schematic diagram of a pressure tester according to the present invention.

Fig. 3 is a circuit diagram of the pressure tester provided by the invention.

Fig. 4 is a flowchart of a confining pressure control method according to the present invention.

Wherein: 1-a hydraulic pump, 2-an electromagnetic directional valve, 3-an overflow valve, 4-a booster directional valve, 5-a booster cylinder, 6-a first hydraulic control one-way valve, 7-a second hydraulic control one-way valve, 8-a third hydraulic control one-way valve, 9-an energy accumulator, 10-a pressure measuring instrument, 11-an oil cylinder and 12-a fourth hydraulic control one-way valve;

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, a confining pressure control system comprises a hydraulic pump 1, the hydraulic pump 1 is connected with an external oil tank and is connected to one end P of a first pipeline in an electromagnetic directional valve 2 and an input end of an overflow valve 3, an output end of the overflow valve 3 is connected to the oil tank, the other end a of the first pipeline in the electromagnetic directional valve 2 is respectively connected with a liquid inlet of a first hydraulic control one-way valve 6, a pipeline end of a booster directional valve 4 and a liquid inlet of a second hydraulic control one-way valve 7, a liquid outlet of the second hydraulic control one-way valve 7 is connected to an oil cylinder 11, a connecting pipeline between the second hydraulic control one-way valve 7 and the oil cylinder 11 is provided with an energy accumulator 9 and a pressure measuring instrument 10, a liquid outlet of the first hydraulic control one-way valve 6 is respectively connected with a liquid inlet of a third hydraulic control one-way valve 8 and the top of a booster cylinder 5, the bottom, the middle part of the booster cylinder 5 is connected to a valve core of the booster reversing valve 4 and a liquid inlet of a fourth hydraulic control one-way valve 12, a liquid outlet of the fourth hydraulic control one-way valve 12 is connected with one end B of a second pipeline in the electromagnetic reversing valve 2, the other end T of the second pipeline in the electromagnetic reversing valve 2 is connected to an external oil tank, and a liquid outlet of the third hydraulic control one-way valve 8 is connected to the oil cylinder 11.

As shown in fig. 2, the pressure measuring instrument 10 includes a pressure sensor U4, an AD conversion module, a single chip microcomputer module, a display module, and a wireless communication module, the pressure sensor is connected to the AD conversion module, and the single chip microcomputer module is connected to the AD conversion module, the display module, and the wireless communication module, respectively.

In this embodiment, BST-TGY-7.0G may be used as the pressure gauge 10.

As shown in fig. 3, the pressure sensor U4 is of the type PTH702H, and the 1 st pin of the pressure sensor U4 is connected to + 24V.

The AD conversion module comprises an AD conversion chip U3 with the model number of TCL549CD, a REF + pin and a VCC pin of the AD conversion chip U3 are both connected with +5V voltage, a REF-pin and a GND pin of the AD conversion chip U3 are grounded, and an ANLGIN pin of the AD conversion chip U3 is connected with a No. 3 pin of a pressure sensor U4.

The single-chip microcomputer module comprises a single-chip microcomputer U1 with the model number of AT89S51, the XTAL1 pin of the single-chip microcomputer U1 is respectively connected with one end of a crystal oscillator X1 and a grounding capacitor C2, the XTAL2 pin of the single-chip microcomputer U1 is respectively connected with a crystal oscillator X1 and a grounding capacitor C3, the RST pin of the single-chip microcomputer U1 is respectively connected with one end of a resistor R1, a grounding capacitor C1 and a grounding switch K1, the other end of the resistor R1 is adjacent to +5V voltage, the P1.0 pin of the single-chip microcomputer U1 is connected with the CLK pin of an AD conversion chip U3, the P1.1 pin of the single-chip microcomputer U1 is connected with the DO pin of the AD conversion chip U3, and the P1.2 pin of the single-chip microcomputer U1 is connected with the CS pin of.

The display module comprises a display screen LCD1 with the model of LM1602, a VSS pin of a display screen LCD1 is connected with +5V voltage, a VDD pin of a display screen LCD1 is grounded, a VEE pin of the display screen LCD1 is connected with a sliding end of a sliding resistor RV1, a first fixed end of the sliding resistor RV1 is grounded, a second fixed end of the sliding resistor RV1 is connected with +5V voltage, an RS pin, a RW pin and an E pin of the display screen LCD1 are connected with a P2.0 pin, a P2.1 pin and a P2.2 pin of a singlechip U1 in a one-to-one correspondence mode, pins D0 to D7 of the display screen LCD1 are connected with a pin 2 to a pin 9 of the RP exclusion 1 in a one-to-one mode, a pin 2 to a pin 9 of the RP1 are connected with a pin P0.0 to a pin P0.7 in a one-to one mode, and a pin 1 of the RP1 of the exclusion singlechip.

The wireless communication module comprises a wireless communication integrated board U2 with the model of NRF24L01+, a CE pin, a CSN pin, an SCK pin, an MOSI pin, a MISO pin and an IRQ pin of the wireless communication integrated board U2 are respectively connected with P3.0 to P3.5 of the single chip microcomputer U1 in a one-to-one correspondence mode, a VCC pin of the wireless communication integrated board U2 is connected with +3.3V voltage, and a GND pin of the wireless communication integrated board U2 is grounded.

In this embodiment, pressure sensor U4 measures pressure, obtains analog signal, and analog signal passes through AD conversion module and converts digital signal into, transmits digital signal to single chip module and handles, obtains the pressure value to pass through the display screen display with the pressure value and transmit to computer equipment through wireless communication module.

As shown in fig. 4, a confining pressure control method includes the following steps:

s1, placing the rock sample into an oil cylinder, using a PLC (programmable logic controller) as a controller of the confining pressure control system, and enabling the conduction direction of the electromagnetic directional valve 2 to be the initial conduction direction from the hydraulic pump 1 to the second hydraulic control one-way valve 7 and the booster directional valve 4 to be the initial conduction direction from the booster cylinder 5 to the electromagnetic directional valve 2;

s2, controlling the hydraulic pump 1 to work through the PLC, pumping oil in an external oil tank to the electromagnetic directional valve 2, and enabling the oil to reach the oil cylinder 11 through the second hydraulic control one-way valve 7, the energy accumulator 9 and the pressure measuring instrument 10 in sequence;

s3, judging whether the second hydraulic control one-way valve 7 is automatically closed or not, if so, entering a step S4, otherwise, continuing judging until the second hydraulic control one-way valve 7 is automatically closed, and entering a step S4;

s4, pumping oil in an external oil tank to the electromagnetic directional valve 2, enabling the oil to enter a top piston HP in the pressure cylinder 5 through the first hydraulic control one-way valve 6, and pushing the top piston HP and a bottom piston LP to the bottom of the pressure cylinder 5;

s5, driving a valve core of a supercharger reversing valve 4 to move downwards through oil to the supercharger reversing valve 4 to reverse, enabling the oil to reach the bottom of a supercharging cylinder 5 from an electromagnetic reversing valve 2, pushing a top piston HP and a bottom piston LP to move upwards, and outputting high-pressure oil;

and S6, enabling the high-pressure oil to sequentially pass through the third hydraulic control one-way valve 8, the energy accumulator 9 and the pressure measuring instrument 10 to reach the oil cylinder 11, measuring confining pressure in real time through the pressure measuring instrument 10, adjusting the pressure in real time according to a confining pressure measuring result, and finishing confining pressure control applied to the fidelity cabin.

In this example, the pressure produced was 140 MPa.

During the confining pressure measurement, the energy is stored through the energy accumulator 9, and when the pressure measured by the pressure measuring instrument 10 is smaller than a set threshold value, the energy of the energy accumulator 9 is released to ensure that the pressure cannot be reduced;

after confining pressure measurement is finished, the hydraulic pump 1 is closed, the conducting direction of the electromagnetic directional valve 2 is from the second hydraulic control one-way valve 7 to the hydraulic pump 1, the fourth hydraulic control one-way valve 12 is conducted, and residual oil in the system sequentially flows back to an external oil tank through the fourth hydraulic control one-way valve 12 and the electromagnetic directional valve 2.