Pressure load control system and method for deep geotechnical engineering disturbance simulation facility

Abstract

The present invention discloses a pressure load control system and method for a deep geotechnical engineering disturbance simulation facility. The system is used to provide a pressure test environment for the main cabin, including a main cabin pressurization and pressure relief unit and a pressure stabilization unit using thermal oil as the working medium. The main cabin pressurization and pressure relief unit is used to pressurize and relieve the main cabin to apply or unload the confining pressure under conditions with large flow changes. The pressure stabilization unit is used to stabilize the main cabin and pressurize, stabilize, and relieve the actuator under conditions with small flow rates to meet pressure test requirements. The control module can control the corresponding hydraulic booster action through a servo valve closed loop according to the target command and feedback from the monitoring module. This application fully considers the characteristics of deep geotechnical engineering disturbance simulation facilities and can accurately control the pressure of the main cabin and the actuator, providing a basis for subsequent rock test and other evaluations.

Description

Technical Field

[0001] The present invention relates to geotechnical engineering tests, and in particular to a pressure load control system and method for a deep geotechnical engineering disturbance simulation facility. Background Art

[0002] The deep rock mass environment has the characteristics of high ground stress, high ground temperature and high karst water pressure. Especially with the increase of underground depth, the high stress field in the deep rock mass accumulates, which makes the implementation of deep geotechnical engineering extremely difficult. Therefore, experimental research is needed.

[0003] To simulate deep multi-field coupled environments and engineering disturbance conditions, and to precisely observe and control the evolution of the rock mass's internal discontinuous structure and external nonlinear behavior, numerous geotechnical disturbance simulation facilities have been developed for experimental research. However, in geotechnical engineering, the general rule is to apply lower pressures to large structures and higher pressures to small ones. Current simulation facilities are generally unable to apply ultra-high pressures to large structures, nor can they accurately and stably control pressures. In particular, they are unable to maintain long-term, stable pressure environments (e.g., simulating geotechnical environments at depths of 5,000 meters for weeks or even months). Summary of the Invention

[0004] The purpose of the present invention is to provide a pressure load control system and method for a deep geotechnical engineering disturbance simulation facility. This application fully considers the characteristics of the deep geotechnical engineering disturbance simulation facility, can accurately control the pressure of the main cabin and the actuator, and provides a basis for subsequent rock tests and other evaluations.

[0005] The technical solution adopted in the present invention is:

[0006] A deep geotechnical engineering disturbance simulation facility pressure load control system is used to provide a pressure test environment for the main cabin, including a main cabin pressurization and pressure relief unit and a pressure stabilizing unit with thermal oil as the working medium; the main cabin pressurization and pressure relief unit is used to pressurize and relieve the main cabin for working conditions with large flow changes, thereby applying or unloading the surrounding pressure, including an electric liquid booster pump driven by a constant torque variable frequency motor for pressurization, a clean oil tank for oil supply, and a low-level oil tank for storing return oil. The pipeline between the electric liquid booster pump and the main cabin is provided with a manual pressure relief branch, a remote pressure relief branch with different pressure relief rates, a safety protection branch, and an emergency branch. Emergency remote pressure relief branch, emergency manual pressure relief branch; the pressure stabilizing unit is used for stabilizing the pressure of the main cabin and boosting, stabilizing and releasing the pressure of the actuator to meet the pressure test requirements for the working conditions with small flow, including the hydraulic booster corresponding to the main cabin and each actuator, the servo valve corresponding to each hydraulic booster, the hydraulic pump for supplying pressure to the hydraulic booster, the clean oil tank 2 for oil supply, the pressure relief oil tank for storing pressure relief oil, the monitoring module and the control module. The monitoring module is used to monitor the status of the hydraulic booster and the test specimen. The control module can control the corresponding hydraulic booster action through the servo valve closed loop according to the target command and the feedback from the monitoring module.

[0007] Preferably, a manual or electric ball valve and a filter are provided near the upstream of the electric liquid booster pump, and an ultra-high pressure one-way valve, an ultra-high pressure manual needle valve, an ultra-high pressure pneumatic needle valve, and a pressure monitoring component are provided near the downstream of the electric liquid booster pump.

[0008] Preferably, two electric liquid booster pumps are used in parallel; one is a large-flow booster pump, which works when pressurization is required at a boosting rate of more than 2MPa / min; the other is a small-flow booster pump, which works when pressurization is required at a boosting rate of less than 2MPa / min; the two shall not work at the same time.

[0009] Preferably, an ultra-high pressure manual pressure relief valve is provided on the manual pressure relief branch, and two remote pressure relief branches are provided with two parallel ultra-high pressure electric regulating valves and one ultra-high pressure pneumatic needle valve. The ultra-high pressure electric regulating valve adjusts the valve opening through PID to accurately control the pressure relief rate of the main cabin. The two remote pressure relief branches are used individually or in combination according to the required pressure relief rate.

[0010] Preferably, ultra-high pressure filters are provided on both the manual pressure relief branch and the remote pressure relief branch, an ultra-high pressure cooler is provided on the pipeline between the electric liquid booster pump and the main cabin, and a cooling coil is provided in the low-level oil tank.

[0011] Preferably, a bursting disc is provided on the safety protection branch, an ultra-high pressure pneumatic needle valve is provided on the emergency remote pressure relief branch, and an ultra-high pressure manual needle valve is provided on the emergency manual pressure relief branch.

[0012] Preferably, an electric heating device is provided near the main cabin on the pipeline between the electric liquid booster pump and the main cabin.

[0013] Preferably, pressure monitoring devices are provided on the pipeline between the electric liquid booster pump and the main cabin, the manual pressure relief branch, the remote pressure relief branch with different pressure relief rates, and the air source system for supplying air to the pneumatic valves in the main cabin pressurization and pressure relief unit. Interlocking protection is achieved through feedback from the pressure monitoring devices: when the remote pressure relief valve on any remote pressure relief branch is open and the air control valve is closed, the electric liquid booster pump cannot be started and operated; when the valve on the pipeline between the electric liquid booster pump and the main cabin is not open, the electric liquid booster pump cannot be started and operated; When the cooling coil in the low-level oil tank is not opened, the remote pressure relief valve on any remote pressure relief branch cannot be opened; when the difference between any pressure monitoring device and the other pressure monitoring devices is greater than 10MPa, an alarm indication will be given; when the electric heating device near the main cabin on the pipeline between the electric liquid booster pump and the main cabin is not working, pressurization and pressure relief operations cannot be performed; when the liquid level in the clean oil tank is low, pressurization and pressure relief operations cannot be performed; when the pressure on the air source system is lower than 0.6MPa, the main cabin pressurization and pressure relief unit shall not work, and an alarm indication will be given.

[0014] Preferably, the monitoring module includes a pressure monitoring component for monitoring the pressure at the low-pressure end and the high-pressure end of the hydraulic booster, a displacement monitoring component for monitoring the displacement of the hydraulic booster piston, and a deformation monitoring component for monitoring the deformation of the sample. The control module can control the corresponding hydraulic booster through a servo valve closed-loop according to the target pressure and the feedback of the pressure monitoring component, can calculate the volume and flow of the medium injected into the actuator or the main cabin according to the feedback of the displacement monitoring component, can control the corresponding hydraulic booster through a servo valve closed-loop according to the required volume and flow of the medium injected into the actuator or the main cabin and the feedback of the displacement monitoring component, and can control the corresponding hydraulic booster through a servo valve closed-loop according to the target deformation of the sample and the feedback of the deformation monitoring component.

[0015] Preferably, a filter is provided near the upstream of the hydraulic pump, a high-pressure fine oil filter, a one-way valve and a proportional relief valve are provided near the downstream of the hydraulic pump, an ultra-high-pressure cooling filter and an ultra-high-pressure manual needle valve are provided on the output pipeline of each hydraulic booster, and the output pipeline of the hydraulic booster corresponding to the actuator is connected to the pressure relief tank through a branch with a bursting disc.

[0016] A method for controlling a pressure load of a deep geotechnical engineering disturbance simulation facility is based on the above-mentioned pressure load control system of the deep geotechnical engineering disturbance simulation facility. When conducting a test, the internal pressure of the actuator is first slowly increased through a pressure stabilizing unit, and then the main cabin is pressurized to the required ambient pressure at a required pressurization rate through the main cabin pressurization and pressure relief unit, and the main cabin is pressure-stabilized through the pressure stabilizing unit. Then, the internal pressure of the actuator is increased through the pressure stabilizing unit at a required pressurization rate, and a certain pressure is applied to the sample and then stabilized. Then, according to the test requirements, the actuator is precisely controlled by the pressure stabilizing unit to test the sample. After the test, the internal pressure of the actuator is first synchronously unloaded to the ambient pressure at a required rate through the pressure stabilizing unit, and then the main cabin ambient pressure is unloaded at a required rate through the main cabin pressurization and pressure relief unit, and the internal pressure of the actuator is unloaded to atmospheric pressure through the pressure stabilizing unit.

[0017] The beneficial effects of the present invention are:

[0018] This application fully considers the characteristics of deep geotechnical engineering disturbance simulation facilities: since the main cabin has a large internal volume and the required flow rate changes are relatively large, the pressure increase and pressure relief are achieved by an electric liquid booster pump in conjunction with the valves on each pressure relief branch, so the main cabin pressurization and pressure relief unit is adopted; at the same time, the flow rate required for the pressure stabilization of the main cabin and the pressure boost, pressure stabilization and pressure relief of each actuator is relatively small, and the pressure control accuracy is high, which is achieved by an electro-hydraulic servo-controlled hydraulic booster, so a pressure stabilization unit is adopted. In the main cabin pressurization and pressure relief unit, the dangers of ultra-high pressure conditions are fully taken into consideration. Each pressure relief branch can perform functions such as slow pressure relief, rapid pressure relief, manual pressure relief, and manual pressure relief in emergency situations. In the pressure stabilizing unit, the hydraulic booster can convert a smaller pressure into a larger pressure, reducing the dangers of ultra-high pressure conditions. In addition, the control module and the monitoring module are used to achieve closed-loop control, making the adjustment more precise and rapid. The main cabin pressurization and pressure relief unit and the pressure stabilizing unit are independent of each other but can be used in conjunction with each other. They can accurately control the pressure of the main cabin and the actuator, thereby providing a pressure test environment and laying the foundation for subsequent rock tests and other evaluations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 Schematic diagram of the main cabin pressurization and relief unit in an embodiment of the present invention.

[0021] Figure 2 Schematic diagram of the air source system of the main cabin pressurization and relief unit in an embodiment of the present invention.

[0022] Figure 3 Schematic diagram of a voltage stabilizing unit in an embodiment of the present invention.

[0023] Figure 4 It is a schematic diagram of the pressure closed-loop control principle in an embodiment of the present invention.

[0024] Figure 5 1 is a schematic diagram of the displacement closed-loop control principle in an embodiment of the present invention.

[0025] Figure: 1.1a~1.3a, ball valve; 2a, oil tank 1; 3a, electric ball valve; 4.1a~4.2a, filter; 5.1a~5.2a, electric liquid booster pump; 6.1a~6.2a, ultra-high pressure check valve; 7.1a~7.3a, ultra-high pressure manual needle valve; 8.1a~8.6a, ultra-high pressure pneumatic needle valve; 9a, ultra-high pressure manual regulating valve; 10.1a~10.3a, ultra-high pressure filter; 11.1a~11.4a, ultra-high pressure electric regulating valve; 12a, bursting disc; 13a, ultra-high pressure cooler; 14a, electric heating device; 15, main cabin; 16a, low-level oil Box; 17a, cooling coil; 18a, integrated air compressor; 19a, oil clean tank 2; 20a, manual ball valve; 21.1a~21.2a, filter; 22a, hydraulic pump; 23a, high-pressure fine oil filter; 24a, check valve; 25a, pressure gauge stop valve; 26a, proportional relief valve; 27.1a~27.5a, electro-hydraulic servo valve; 28.1a~28.5a, hydraulic intensifier; 29.1a~29.4a, bursting disc; 30.1a~30.5a, ultra-high-pressure cooling filter; 31.1a~31.5a, ultra-high-pressure manual needle valve; 32.1~32.4, actuator. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0028] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0029] Example 1

[0030] A certain project needs to simulate the stress conditions at 5000m underground and perform ultra-high pressure loading on a large-scale rock sample of 800mm*800mm*800mm, of which the total volume of the main cabin 15 is 3.3m 3 The maximum working pressure is 130MPa, and the ultra-high pressure needs to be maintained for 1 month; 4 actuators (32.1~32.4) are used, which are placed in the y and z directions respectively. The maximum working pressure is 150MPa, the pressure control accuracy is ±1%FS, the pressure increase rate is 1~10MPa / min (adjustable), and the ultra-high pressure needs to be maintained for 1 month.

[0031] In order to provide a pressure test environment for the above-mentioned deep geotechnical engineering disturbance simulation facility, this embodiment provides a deep geotechnical engineering disturbance simulation facility pressure load control system, including a main cabin pressurization and pressure relief unit and a pressure stabilization unit using thermal oil as the working medium; the specific contents are as follows.

[0032] 1. Main cabin pressurization and relief unit

[0033] The main cabin pressurization and pressure relief unit is used to pressurize and relieve the main cabin 15 to apply or unload the surrounding pressure for the working conditions with large flow changes, such as Figure 1 As shown, it mainly includes an electric liquid booster pump (5.1a, 5.2a) for pressurization and driven by a constant torque variable frequency motor, a clean oil tank 2a for oil supply, and a low-level oil tank 16a for storing return oil. The pipeline between the electric liquid booster pump (5.1a, 5.2a) and the main cabin 15 is provided with a manual pressure relief branch, a remote pressure relief branch with different pressure relief rates, a safety protection branch, an emergency remote pressure relief branch, and an emergency manual pressure relief branch.

[0034] In order to ensure stable and reliable operation, in this embodiment, it is preferred that: Figure 1 As shown, a manual ball valve 1.2a or an electric ball valve 3a and a filter (4.1a, 4.2a) are provided near the upstream of the electric liquid booster pump (5.1a, 5.2a), and an ultra-high pressure one-way valve (6.1a, 6.2a), an ultra-high pressure manual needle valve (7.1a, 7.2a), an ultra-high pressure pneumatic needle valve (8.1a, 8.2a), and a pressure monitoring component are provided near the downstream of the electric liquid booster pump (5.1a, 5.2a).

[0035] In order to ensure reliable pressure boosting and convenient adjustment, in this embodiment, preferably: Figure 1As shown, two parallel electric liquid booster pumps (5.1a and 5.2a) are used. One is a high-flow booster pump, operating when a boost rate of 2 MPa / min or higher is required; the other is a low-flow booster pump, operating when a boost rate of less than 2 MPa / min is required. Both pumps must not operate simultaneously. The high-flow booster pump has a rated output flow of 28 L / min, with an adjustable range of 10%-100%. The low-flow booster pump has a rated output flow of 8 L / min, with an adjustable range of 10%-100%. The output flow is varied by adjusting the frequency of the constant-torque variable-frequency motor, enabling arbitrary adjustment of the boost rate from 1 to 10 MPa / min.

[0036] In order to ensure reliable pressure relief, in this embodiment, preferably: Figure 1 As shown, a manual pressure relief branch is provided with an ultra-high pressure manual pressure relief valve 9a, one remote pressure relief branch is provided with two parallel ultra-high pressure electric regulating valves (11.1a, 11.2a) and an ultra-high pressure pneumatic needle valve 8.3a, and another remote pressure relief branch is also provided with two parallel ultra-high pressure electric regulating valves (11.3a, 11.4a) and an ultra-high pressure pneumatic needle valve 8.4a. The ultra-high pressure electric regulating valves (11.1a-11.4a) use PID to adjust the valve opening to accurately control the pressure relief rate of the main cabin 15. The two remote pressure relief branches are used individually or in combination according to the required pressure relief rate.

[0037] In this embodiment, preferably: Figure 1 As shown, ultrahigh-pressure filters (10.1a-10.3a) are installed on both the manual and remote pressure relief branches. An ultrahigh-pressure cooler 13a is installed in the pipeline between the electric liquid booster pumps (5.1a, 5.2a) and the main compartment 15. A cooling coil 17a is located in the low-level oil tank 16a. The medium flowing out of the main compartment 15 contains foreign matter and impurities and is high in temperature. The ultrahigh-pressure filters (10.1a-10.3a) filter the leaked medium to protect downstream equipment. The ultrahigh-pressure cooler 13a cools the high-temperature thermal oil during pressure relief. Since the leaked medium cannot be discharged directly, it must be discharged to the low-level oil tank 16a for storage. The cooling coil 17a further cools the medium to room temperature.

[0038] In this embodiment, preferably: Figure 1 As shown, a bursting disc 12a is provided on the safety protection branch, an ultra-high pressure pneumatic needle valve 8.5a is provided on the emergency remote pressure relief branch, and an ultra-high pressure manual needle valve 7.3a is provided on the emergency manual pressure relief branch to ensure reliable emergency pressure relief.

[0039] In this embodiment, preferably: Figure 1As shown, an electric heating device 14a is provided near the main cabin 15 on the pipeline between the electric liquid booster pump (5.1a, 5.2a) and the main cabin 15. The electric heating device can heat the medium pressed into the main cabin 15 to ensure that the environment in the main cabin 15 and the temperature field of the test piece do not change.

[0040] In this embodiment, preferably, each pneumatic valve in the main cabin pressurization and pressure relief unit is uniformly supplied with air by the air source system, such as Figure 2 As shown, the air source system adopts an integrated air compressor 18a (including a screw air compressor, a refrigerated dryer, a precision filter, an air storage tank, etc.), the main line of which is equipped with components such as a pressure sensor and a pressure reducing valve, and each branch line is equipped with an electric control valve and a one-way throttle valve.

[0041] In this embodiment, preferably, Figure 1 and Figure 2 As shown, the pipelines between the electric liquid booster pumps (5.1a, 5.2a) and the main cabin 15, the manual pressure relief branch, the remote pressure relief branch with different pressure relief rates, and the air source system that supplies air to the pneumatic valves in the main cabin pressurization and pressure relief unit are all equipped with pressure monitoring devices. Interlocking protection is achieved through feedback from the pressure monitoring devices: when the remote pressure relief valve on any remote pressure relief branch is opened and the air control valve is closed, the electric liquid booster pumps (5.1a, 5.2a) cannot be started and operated; when the valves on the pipelines between the electric liquid booster pumps (5.1a, 5.2a) and the main cabin 15 are not opened, the electric liquid booster pumps (5.1a, 5.2a) cannot be started and operated. 2a) Unable to start and operate; when the cooling coil 17a in the low-level oil tank 16a is not open, the remote pressure relief valve on any remote pressure relief branch cannot be opened; when the difference between any pressure monitoring device and the other pressure monitoring devices is greater than 10MPa, an alarm indication will be issued; when the electric heating device 14a near the main cabin 15 on the pipeline between the electric liquid booster pump (5.1a, 5.2a) and the main cabin 15 is not operating, pressurization and pressure relief operations cannot be performed; when the liquid level in the clean oil tank 2a is low, pressurization and pressure relief operations cannot be performed; when the pressure on the gas source system is less than 0.6MPa, the main cabin pressurization and pressure relief unit shall not operate, and an alarm indication will be issued. Interlocking protection is implemented to prevent improper operation.

[0042] 2. Voltage stabilization unit

[0043] The pressure stabilizing unit is used for stabilizing the pressure of the main chamber 15 (for example, for 1 month) and pressurizing, stabilizing (for example, for 1 month) and relieving the pressure of the actuators (32.1~32.4) in order to meet the pressure test requirements, such as Figure 3As shown, it mainly includes hydraulic boosters (28.1a~28.5a) corresponding to the main cabin 14 and each actuator (32.1~32.4), servo valves corresponding to each hydraulic booster (28.1a~28.5a), a hydraulic pump 22a for supplying pressure to the hydraulic booster (28.1a~28.5a), a clean oil tank 219a for oil supply, a pressure relief oil tank for storing pressure relief oil, a monitoring module, and a control module. The monitoring module is used to monitor the status of the hydraulic booster (28.1a~28.5a) and the sample. The control module can control the corresponding hydraulic booster (28.1a~28.5a) through the servo valve closed loop according to the target command and the feedback of the monitoring module.

[0044] The hydraulic booster (28.1a~28.5a) operates as follows: low-pressure filling to achieve rapid oil supply; boosting stage to achieve high-frequency movement and continuous output of high-pressure oil; automatic pressure maintenance, after reaching mechanical balance, the piston will stop moving. When the pressure on the high-pressure side decreases due to factors such as load reduction or leakage, the high and low pressure pistons will lose mechanical balance and automatically circulate to replenish pressure; unloading.

[0045] In this embodiment, preferably: the monitoring module includes a pressure monitoring component for monitoring the pressure at the low-pressure end and the high-pressure end of the hydraulic booster (28.1a~28.5a), a displacement monitoring component for monitoring the displacement of the piston of the hydraulic booster (28.1a~28.5a), and a deformation monitoring component for monitoring the deformation of the sample. The control module can control the corresponding hydraulic booster (28.1a~28.5a) through a servo valve closed loop according to the target pressure and the feedback of the pressure monitoring component, see Figure 4 , can convert the volume and flow of the medium injected into the actuator (32.1~32.4) or the main cabin 15 according to the feedback of the displacement monitoring unit, and can control the corresponding hydraulic booster (28.1a~28.5a) through the servo valve closed loop according to the required volume and flow of the medium injected into the actuator (32.1~32.4) or the main cabin 15 and the feedback of the displacement monitoring unit, see Figure 5 , can control the corresponding hydraulic booster (28.1a~28.5a) through the servo valve closed-loop control according to the target deformation of the specimen and the feedback from the deformation monitoring part; this setting can not only achieve high-precision control during the test, but also dual closed-loop control of pressure and displacement, which is safer and more reliable.

[0046] In this embodiment, the low-pressure chamber of the hydraulic booster (28.1a~28.5a) uses a pressure sensor with a range of 20MPa, and the high-pressure chamber uses a pressure sensor with a range of 160MPa. The piston rod of the hydraulic booster (28.1a~28.5a) is installed with a magnetostrictive displacement sensor (LVDT), which can accurately measure the displacement data of the piston and then convert it into the volume and flow of the medium injected into the actuator and the main chamber. A total of 14 deformation sensors are installed on the specimen.

[0047] Among them: the control module processes the data fed back by the monitoring module in real time (data amplification, feedback comparison, difference adjustment, PID operation, etc.) to complete the adjustment of the servo valve drive signal (that is, the adjustment of the target value). The time of such an adjustment cycle is only 20ms at most. Through continuous adjustment, the target can be achieved in a few cycles, allowing the system to accurately and quickly respond to changes in the stress and strain of the test piece, ensuring that the control accuracy of the entire system reaches ±1%FS.

[0048] In this embodiment, preferably: Figure 3 As shown, a filter 21.2a is provided near the upstream of the hydraulic pump 22a, and a high-pressure fine oil filter 23a, a one-way valve 24a and a proportional relief valve 26a are provided near the downstream of the hydraulic pump 22a to ensure reliable operation.

[0049] In this embodiment, preferably: Figure 3 As shown, an ultra-high pressure cooling filter (30.1a~30.5a) and an ultra-high pressure manual needle valve (31.1a~31.5a) are provided on the output pipeline of each hydraulic booster (28.1a~28.5a), and the output pipeline of the hydraulic booster (28.2a~28.5a) corresponding to the actuator (32.1~32.4) is connected to the pressure relief tank through a branch with a bursting disc (29.1a~29.4a).

[0050] This application fully considers the characteristics of deep geotechnical engineering disturbance simulation facilities, and the overall pressure control plan is:

[0051] Since the main cabin 15 has a large internal volume (approximately 3.3m 3 ), the required flow rate change is also relatively large. The pressure increase and pressure relief are achieved by electric liquid booster pumps (5.1a, 5.2a) in conjunction with valves on each pressure relief branch. Therefore, the main cabin pressurization and pressure relief unit is used;

[0052] At the same time, the flow rate required for the pressure stabilization of the main cabin 15 and the pressure boost, pressure stabilization, and pressure relief of each actuator is relatively small, and high pressure control accuracy is required. This is achieved by using an electro-hydraulic servo-controlled hydraulic booster (28.1a~28.5a), so a pressure stabilization unit is used.

[0053] For the main cabin 15, its volume is relatively large, and about 170L of medium needs to be injected from 0 to 100MPa (the initial condition is that the main cabin is already filled with medium before pressurization). At this stage, electric liquid booster pumps (5.1a, 5.2a) are selected for pressurization. The electric liquid booster pumps (5.1a, 5.2a) are equipped with constant torque variable frequency motors. The output flow rate can be changed by adjusting the motor frequency, and the pressurization rate can be adjusted arbitrarily from 1 to 10MPa / min. The hydraulic booster 28.1a only intervenes in the pressure maintenance stage; for each actuator (32.1~32.4), its capacity is The volume is very small, and the amount of oil required for oil replenishment is not large. The 0-150MPa pressurization stage and the subsequent pressure maintenance stage and pressure relief stage are all completed by the hydraulic booster (28.2a~28.5a); the main cabin 15 has different pressure stabilization requirements from the actuators (32.1~32.4) for pressurization and pressure maintenance, so different types of hydraulic boosters need to be selected. The hydraulic booster (28.2a~28.5a) corresponding to the actuator (32.1~32.4) has a design pressure ratio of 1:10. When the low-pressure chamber input is 15MPa, the high-pressure chamber output pressure is 150MPa.

[0054] In the main cabin pressurization and pressure relief unit, the dangers of ultra-high pressure conditions are fully taken into account. Each pressure relief branch can perform functions such as slow pressure relief, rapid pressure relief, manual pressure relief, and manual pressure relief in emergency situations. In the pressure stabilization unit, the hydraulic booster (28.1a~28.5a) can convert a smaller pressure into a larger pressure, reducing the dangers of ultra-high pressure conditions. In addition, closed-loop control is achieved using the control module and monitoring module, making the adjustment more precise and rapid. The main cabin pressurization and pressure relief unit and the pressure stabilization unit are independent of each other but can be used in conjunction with each other. They can accurately control the pressure of the main cabin 15 and the actuator (32.1~32.4), thereby providing a pressure test environment and laying the foundation for subsequent rock test and other evaluations.

[0055] Example 2

[0056] The present embodiment discloses a method for controlling a pressure load of a deep geotechnical engineering disturbance simulation facility, based on the above-mentioned deep geotechnical engineering disturbance simulation facility pressure load control system. When conducting a test, the internal pressure of the actuator (32.1-32.4) is first slowly increased by a pressure stabilizing unit, and then the main cabin 15 is pressurized to a required confining pressure at a required pressurization rate by the main cabin pressurization and pressure relief unit, and the main cabin 15 is pressure-stabilized by the pressure stabilizing unit. Then, the internal pressure of the actuator (32.1-32.4) is increased by the pressure stabilizing unit at a required pressurization rate, and a certain pressure is applied to the sample and then stabilized. Then, the actuator is precisely controlled by the pressure stabilizing unit according to the test requirements to test the sample. After the test, the internal pressure of the actuator (32.1-32.4) is first synchronously unloaded to the confining pressure at a required rate by the pressure stabilizing unit, and then the confining pressure of the main cabin 15 is unloaded at a required rate by the main cabin pressurization and pressure relief unit, and the internal pressure of the actuator (32.1-32.4) is unloaded to atmospheric pressure by the pressure stabilizing unit.

[0057] The system can complete a series of geotechnical engineering tests, including three-dimensional synchronous pressure loading test, three-dimensional asynchronous pressure loading test, three-dimensional stress gradient loading test, main chamber constant pressure control test, constant velocity displacement loading test, displacement gradient loading test, deformation closed-loop control test, stress and strain coupling loading test, multi-terminal control loading test, PLC external data test, and pressure unloading test. It can precisely observe and control the evolution of the internal structure or external behavior of large-scale rock samples, providing support and guarantee for the development of new theories and methods in deep geotechnical engineering, the performance testing of deep geotechnical engineering materials and equipment, and the exploration of new technologies for deep geotechnical engineering design and construction. Two tests are listed below.

[0058] Test 1, taking the constant minimum principal strain rate control test as an example, for a rock sample without pore pressure:

[0059] Step S1, slowly increasing the internal pressure of the actuator (32.1-32.4) through the pressure stabilizing unit and making the actuator (32.1-32.4) contact the sample, controlling the output pressure of the actuator (32.1-32.4) to prevent the sample from being eccentric and the contact force from being too large;

[0060] Step S2: The main cabin 15 is pressurized to the required ambient pressure ( X = y = Z ) and stabilize the main cabin pressure through the pressure stabilizing unit;

[0061] Step S3: Increase the internal pressure of the actuator (Y direction, Z direction) at a constant rate through the pressure stabilizing unit to apply a certain pressure (s y =s z ) after voltage stabilization;

[0062] Step S4: Increase the internal pressure (z) of the pair of actuators to a set value and stabilize the pressure (for a set time) at a constant minimum principal strain rate (i.e., expansion rate, strain in the direction perpendicular to the free surface) through the pressure stabilization unit. Then repeat the loading-unloading-stabilization or unloading-loading-stabilization cycle until the specimen fails. The entire process is set in advance with limits on the stress on the specimen and the deformation of the actuator (32.1-32.4). If the set value is exceeded, the test is automatically terminated, or manually terminated according to the test situation.

[0063] Step S5: Synchronously unloading the internal pressure of the actuator (in the Y direction and the Z direction) to the confining pressure at a constant contraction rate through the pressure stabilizing unit;

[0064] Step S6: unload the surrounding pressure of the main cabin 15 at a constant pressure reduction rate through the main cabin pressurization and pressure relief unit, and unload the internal pressure of the actuator (32.1~32.4) to atmospheric pressure through the pressure stabilization unit.

[0065] Test 2, taking the three-axis constant stress control test as an example, for the rock sample without pore pressure:

[0066] Step S1: slowly increase the internal pressure of the actuator (32.1-32.4) to 2-5 MPa through the pressure stabilizing unit and stabilize the pressure;

[0067] Step S2: The main cabin 15 is pressurized to the required ambient pressure (s) at a constant pressurization rate through the main cabin pressurization and pressure relief unit. X =s y =s Z ) and stabilizing the pressure of the main cabin 15 through the pressure stabilizing unit; synchronously increasing the internal pressure of the actuator (32.1~32.4) at the same constant pressurization rate and stabilizing the pressure through the pressure stabilizing unit;

[0068] Step S3: Increase the internal pressure of the actuator (Y direction, Z direction) at a constant pressure rate through the pressure stabilizing unit, and apply a certain pressure (s y =s z ) after voltage stabilization;

[0069] Step S4: Increase the internal pressure (Z direction) of the pair of actuators to a set value at a constant pressure increase rate through the pressure stabilizing unit and stabilize the pressure (the time can be set). The entire process is set in advance to limit the stress on the specimen and the deformation of the actuator (32.1~32.4). If the set value is exceeded, the test is automatically terminated, or manually terminated according to the test situation.

[0070] Step S5: Synchronously unloading the internal pressure of the actuator (in the Y direction and the Z direction) to the confining pressure at a constant contraction rate through the pressure stabilizing unit;

[0071] Step S6: The main cabin 15 surrounding pressure is unloaded at a constant pressure reduction rate through the main cabin pressurization and pressure relief unit, and the internal pressure of the actuator (32.1-32.4) is unloaded to atmospheric pressure through the pressure stabilization unit.

[0072] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A pressure load control system for a deep geotechnical engineering disturbance simulation facility, characterized by: It is used to provide a pressure test environment for the main cabin, including a main cabin pressurization and pressure relief unit and a pressure stabilizing unit with thermal oil as the working medium; the main cabin pressurization and pressure relief unit is used to pressurize and relieve the main cabin to apply or unload the surrounding pressure under the working conditions of large flow changes, including an electric liquid booster pump driven by a constant torque variable frequency motor for pressurization, a clean oil tank for oil supply, and a low-level oil tank for storing return oil. The pipeline between the electric liquid booster pump and the main cabin is equipped with a manual pressure relief branch, a remote pressure relief branch with different pressure relief rates, a safety protection branch, an emergency remote pressure relief branch, and an emergency manual Pressure relief branch; the pressure stabilizing unit is used for stabilizing the pressure of the main cabin and boosting, stabilizing and releasing the pressure of the actuator to meet the pressure test requirements under the working conditions of small flow. It includes a hydraulic booster corresponding to the main cabin and each actuator, a servo valve corresponding to each hydraulic booster, a hydraulic pump for supplying pressure to the hydraulic booster, a clean oil tank 2 for oil supply, a pressure relief oil tank for storing pressure relief oil, a monitoring module and a control module. The monitoring module is used to monitor the status of the hydraulic booster and the test specimen. The control module can control the corresponding hydraulic booster action through the servo valve closed loop according to the target command and the feedback from the monitoring module.

2. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: A manual or electric ball valve and a filter are provided near the upstream of the electric liquid booster pump, and an ultra-high pressure one-way valve, an ultra-high pressure manual needle valve, an ultra-high pressure pneumatic needle valve and a pressure monitoring component are provided near the downstream of the electric liquid booster pump.

3. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: Two parallel electric liquid booster pumps are used; one is a large-flow booster pump, which works when pressurization is required at a boosting rate of more than 2MPa / min; the other is a small-flow booster pump, which works when pressurization is required at a boosting rate of less than 2MPa / min; the two pumps shall not work at the same time.

4. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: An ultra-high pressure manual pressure relief valve is installed on the manual pressure relief branch, and two remote pressure relief branches are equipped with two parallel ultra-high pressure electric regulating valves and one ultra-high pressure pneumatic needle valve. The ultra-high pressure electric regulating valve adjusts the valve opening through PID to accurately control the pressure relief rate of the main cabin. The two remote pressure relief branches are used individually or in combination according to the required pressure relief rate.

5. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: Ultra-high pressure filters are installed on both the manual pressure relief branch and the remote pressure relief branch, an ultra-high pressure cooler is installed on the pipeline between the electric liquid booster pump and the main cabin, and a cooling coil is installed in the low-level oil tank.

6. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: The safety protection branch is equipped with a bursting disc, the emergency remote pressure relief branch is equipped with an ultra-high pressure pneumatic needle valve, and the emergency manual pressure relief branch is equipped with an ultra-high pressure manual needle valve.

7. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: An electric heating device is provided near the main cabin on the pipeline between the electric liquid booster pump and the main cabin.

8. The pressure load control system for deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: The pipelines between the electric liquid booster pump and the main cabin, the manual pressure relief branch, the remote pressure relief branch with different pressure relief rates, and the air source system for supplying air to the pneumatic valves in the main cabin pressurization and pressure relief unit are all equipped with pressure monitoring components. Interlocking protection is achieved through the feedback of the pressure monitoring components: when the remote pressure relief valve on any remote pressure relief branch is opened and the air control valve is closed, the electric liquid booster pump cannot be started and operated; when the valve on the pipeline between the electric liquid booster pump and the main cabin is not opened, the electric liquid booster pump cannot be started and operated; when the low When the cooling coil in the oil tank is not opened, the remote pressure relief valve on any remote pressure relief branch cannot be opened; when the difference between any pressure monitoring device and the other pressure monitoring devices is greater than 10MPa, an alarm indication will be given; when the electric heating device near the main cabin on the pipeline between the electric liquid booster pump and the main cabin is not working, pressurization and pressure relief operations cannot be performed; when the liquid level in the clean oil tank is low, pressurization and pressure relief operations cannot be performed; when the pressure on the gas source system is lower than 0.6MPa, the main cabin pressurization and pressure relief unit shall not work, and an alarm indication will be given.

9. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: The monitoring module includes a pressure monitoring device for monitoring the pressure at the low-pressure end and the high-pressure end of the hydraulic booster, a displacement monitoring device for monitoring the displacement of the hydraulic booster piston, and a deformation monitoring device for monitoring the deformation of the sample. The control module can control the corresponding hydraulic booster through a servo valve closed loop according to the target pressure and the feedback of the pressure monitoring device, can calculate the volume and flow of the medium injected into the actuator or the main cabin according to the feedback of the displacement monitoring device, can control the corresponding hydraulic booster through a servo valve closed loop according to the required volume and flow of the medium injected into the actuator or the main cabin and the feedback of the displacement monitoring device, and can control the corresponding hydraulic booster through a servo valve closed loop according to the target deformation of the sample and the feedback of the deformation monitoring device.

10. The pressure load control system for a deep geotechnical engineering disturbance simulation facility according to claim 1, characterized in that: A filter is installed near the upstream of the hydraulic pump, and a high-pressure fine oil filter, a one-way valve and a proportional relief valve are installed near the downstream of the hydraulic pump. An ultra-high-pressure cooling filter and an ultra-high-pressure manual needle valve are installed on the output pipeline of each hydraulic booster. The output pipeline of the hydraulic booster corresponding to the actuator is connected to the pressure relief tank through a branch with a bursting disc.

11. A method for controlling pressure loads in a deep geotechnical engineering disturbance simulation facility, characterized by: Based on the deep geotechnical engineering disturbance simulation facility pressure load control system as described in any one of claims 1 to 10; when conducting a test, first slowly increase the internal pressure of the actuator through the pressure stabilizing unit, then pressurize the main cabin to the required confining pressure at the required pressurization rate through the main cabin pressurization and pressure relief unit, and stabilize the main cabin through the pressure stabilizing unit, then increase the internal pressure of the actuator at the required pressurization rate through the pressure stabilizing unit, apply a certain pressure to the sample and then stabilize the pressure, and then accurately control the actuator through the pressure stabilizing unit according to the test requirements to test the sample; after the test, first synchronously unload the internal pressure of the actuator to the confining pressure at the required rate through the pressure stabilizing unit, then unload the main cabin confining pressure at the required rate through the main cabin pressurization and pressure relief unit, and unload the internal pressure of the actuator to atmospheric pressure through the pressure stabilizing unit.

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