CN116290139A

CN116290139A - Pressure self-control device for foundation pile static load test and control method thereof

Info

Publication number: CN116290139A
Application number: CN202310129800.2A
Authority: CN
Inventors: 徐蛟; 杨鑫; 毛勇强; 杨永波; 邹宇; 侯程宇; 林佳龙; 尹中南; 刘守华; 高飞平
Original assignee: WUHAN SINOROCK TECHNOLOGY CO LTD
Current assignee: WUHAN SINOROCK TECHNOLOGY CO LTD
Priority date: 2023-02-17
Filing date: 2023-02-17
Publication date: 2023-06-23

Abstract

The invention discloses a pressure self-control device for a foundation pile static load test and a control method thereof, wherein the pressure self-control device for the foundation pile static load test can automatically pressurize or depressurize according to a real-time pressure value, so that the automatic operation of the whole process is realized; meanwhile, in the control method, different pressure control stages are determined according to the conversion result of the actual pressure value and the target pressure value, and the oil outlet speed of the hydraulic oil of the oil pump is accurately adjusted by correspondingly adjusting the rotating speed of the driving unit, so that the staged pressurization and staged pressure relief of the pressure self-control device are realized, and the high efficiency and the accuracy of the pressure control are both realized.

Description

Pressure self-control device for foundation pile static load test and control method thereof

Technical Field

The invention relates to the field of building foundation pile detection equipment, in particular to a pressure self-control device for a foundation pile static load test and a control method thereof.

Background

The foundation pile static load test principle is as shown in figure 1, a foundation pile 2 is built in a soil layer 1, the bearing capacity of the foundation pile 2 is to be tested, a load supporting frame 3 is firstly built on the ground around the foundation pile 2, then a maximum load 4 (load is generally composed of sand bags or stones) required by the test is piled on the load supporting frame 3, a hydraulic jack 5 is arranged between the foundation pile 2 and the load 4 (the hydraulic jack 5 is arranged at the center position of the top surface of the foundation pile), the jack heads of the hydraulic jack 5 extend outwards to provide supporting force for the load 4 by changing the oil quantity distribution in the hydraulic jack 5, the supporting force provided for the load 4 is larger when the jack heads of the hydraulic jack 5 extend, and the supporting force provided for the load 4 is smaller when the jack heads of the hydraulic jack 5 extend out, and the supporting force provided for the load 4 is equal to the pressure applied by the foundation pile because the hydraulic jack 5 is arranged between the foundation pile 2 and the load 4, the displacement of the foundation pile relative to the foundation pile is measured, and accordingly the bearing capacity of the foundation pile is judged. Based on the principle, various pressure control devices for foundation pile static load tests exist at present, but the high efficiency and the accuracy of the tests are difficult to be considered.

The existing pressure control technology for foundation pile static load test mainly comprises a manual pressure adding and releasing method and an electric oil pump pressure adding and releasing method:

1. manual pressure relief method: according to the method, when the hydraulic jack is matched with the manual pump for use, a valve is locked when the foundation pile is pressurized, a rocker of the manual pump is rocked up and down, hydraulic oil is pressed into the hydraulic jack from an oil storage tank by the manual pump, an oil inlet of the hydraulic jack is provided with a one-way valve, hydraulic oil can only enter the hydraulic jack from the oil inlet and cannot flow out of the oil inlet, the oil quantity in the hydraulic jack is increased, a jack head of the hydraulic jack is pushed to extend outwards, the load pressure is increased, and the real-time pressure provided by the hydraulic jack is read by a pressure gauge on the jack; when the foundation pile is relieved, the valve is unscrewed, hydraulic oil in the hydraulic jack flows into the oil storage tank again from the valve, the hydraulic oil in the hydraulic jack is reduced, and the pressure provided for the load is correspondingly reduced.

The device has simple structure, simple and convenient operation and low cost, but has a plurality of problems: a) The manual pressurization needs to consume large manpower and has low efficiency, and the pressure value and the pile foundation displacement value of the test are recorded by manpower, so that large errors are easy to generate; b) The pressure relief is not well controlled, is easy to be released too quickly, causes excessive pressure relief, and needs to be manually pressurized again; c) The speed of rocking the rocker during pressurization and the degree of unscrewing the unloading valve during pressure relief are entirely dependent on the experience of the operator, making pressure control accuracy difficult to meet.

2. The electric oil pump pressure relief method comprises the following steps: in order to control the pressure conveniently, a control box for controlling the electric oil pump and a computer for sending a pressure increasing and releasing instruction are required to be configured, and a tee joint is arranged at an interface of an oil storage tank in the electric oil pump device and is synchronously controlled by a reversing switch. When the reversing switch is arranged in a pressurizing mode, hydraulic oil flows into a lower oil tank of the hydraulic jack through the oil outlet pipe, and meanwhile, the hydraulic oil in the oil tank of the hydraulic jack flows back into the oil storage tank through the oil return pipe; when the reversing switch is arranged in a pressure relief mode, hydraulic oil flows into an upper oil tank of the hydraulic jack through an oil return pipe, meanwhile, hydraulic oil in the lower oil tank of the hydraulic jack flows back to the oil storage tank through an oil outlet pipe, the hydraulic oil can be prevented from reversely flowing into the oil pump through the oil outlet pipe and the one-way valve arranged on the oil return pipe, the pressure of the hydraulic oil in the lower oil tank of the hydraulic jack can be measured in real time by the oil pressure sensor connected to the oil outlet pipe, the pressure is fed back to the computer, and the computer controls the oil pump to work according to the pressure value.

The pressure control device can realize real-time monitoring of the pressure value, pressurization and pressure relief are controlled by a computer, the testing process is simple, and the method is more reliable than a manual pressurization and pressure relief method, but the following problems also exist: a) The reversing switch is arranged on the electric oil pump, when pressurization and pressure relief reversing are carried out, the switch needs to be manually pulled, if an operator forgets to pull the switch, the condition that the jack is always pressurized when pressure relief possibly occurs, the experiment is affected, and the load table can be overturned when serious; b) According to different oil outlet speeds, the oil pump can be simply divided into a large-flow oil pump and a small-flow oil pump. When the oil pump motor stops running due to the fact that the pressurization or the depressurization reaches a target value, the actual pressure value often exceeds the target value too much to meet the precision requirement; the oil pump with small flow rate is used, the pressure control value is accurate, but the efficiency of the oil pump with small flow rate is low, and when a large load experiment is carried out, the pressure is relieved for a long time.

In conclusion, the manual pressure relief method is completely dependent on manpower in the test process, so that the pressure control is difficult to be accurate and the efficiency is low; the manual reversing is needed for the electric oil pump pressure adding and releasing method, the operation is complex, the electric oil pumps with different flow rates and different control accuracy and efficiency are different, the accuracy and the efficiency cannot be achieved, and the requirements of the accuracy can be met only by the pumps with different flow rates for static load tests with different tonnages. Therefore, based on the technical problems of the existing pressure self-control device for foundation pile static load test, development of a pressure self-control device which is convenient to operate and capable of achieving high efficiency and accuracy in test is needed.

Disclosure of Invention

Aiming at the problems existing in the prior art, the invention provides the pressure self-control device for the foundation pile static load test, which is convenient to operate, high in pressure control efficiency and accurate in whole process automatic control, and the pressure self-control device can automatically switch the pressure adding and releasing modes according to the real-time pressure value so as to realize whole-process automatic operation; meanwhile, in the control method, different pressure control stages are determined according to the conversion result of the real-time pressure value and the target pressure value, the rotating speed of the driving unit is correspondingly adjusted so as to change the oil outlet speed of the hydraulic oil of the oil pump, the graded pressurization and the graded pressure relief of the pressure self-control device are realized, and the pressure control efficiency and the accuracy are both realized.

In order to achieve the above purpose, the invention adopts the technical scheme that:

the pressure self-control device for the foundation pile static load test comprises a control unit, a valve assembly, a driving unit, a power supply, a detection unit, an oil storage tank, an oil outlet pipeline, an oil return pipeline and an execution unit, wherein the valve assembly comprises a loading valve and an unloading valve; the driving unit, the detecting unit, the loading valve and the unloading valve are all connected with the control unit; the output end of the driving unit is connected with the input end of the oil pump, the driving unit drives the oil pump to synchronously rotate, and the control unit controls the rotating speed of the driving unit; one end of the oil inlet pipe of the oil pump is connected with the oil storage tank, and the other end of the oil inlet pipe is selectively connected with the oil outlet pipe and the oil return pipe; the oil outlet pipeline is connected with the oil inlet end of the execution unit, an oil outlet pipeline branch is connected to the oil outlet pipeline, and the oil outlet pipeline branch is connected with the oil storage tank through an unloading valve; the oil return pipeline is connected with an oil outlet end of the execution unit, an oil return pipeline branch is connected between the oil return pipeline and the execution unit, and the oil return pipeline branch is connected with the oil storage tank through a loading valve; the detection unit is arranged on the oil outlet pipeline and is used for measuring the oil pressure in the oil outlet pipeline in real time; the power supply provides electrical energy to the device.

Specifically, the driving unit is a direct current motor, and the oil pump is a high-flow oil pump.

Specifically, a three-way valve is arranged in the oil pump, an oil inlet pipe is selectively connected with an oil outlet pipe or an oil return pipe through the three-way valve, and the execution unit is a hydraulic jack.

Further, a first one-way valve is arranged on an oil outlet pipeline between the three-way valve and the hydraulic jack, and the first one-way valve prevents hydraulic oil from reversely flowing into an oil outlet of the oil pump; and a second one-way valve is arranged on the oil return pipeline between the three-way valve and the hydraulic jack, and the second one-way valve can prevent hydraulic oil from reversely flowing into an oil outlet of the oil pump.

Specifically, the detection unit is arranged as an oil pressure sensor, the oil outlet pipeline is connected with the oil outlet pipeline branch through a tee joint, and the oil pressure sensor is arranged on the tee joint.

Further, a motor speed regulating module is arranged on the control unit, and the motor speed regulating module can regulate the rotating speed of the driving unit.

The invention uses the direct current engine oil pump, and make the oil pump into a large flow state, install the control unit on the oil pump, regulate the rotational speed of the direct current motor through the control unit, thus change the oil outlet speed of the oil pump; in addition, a loading valve and an unloading valve are arranged on an oil outlet pipe and an oil return pipe of the oil pump, the loading valve and the unloading valve are connected with a control unit, and the control unit controls the starting and stopping of the loading valve and the unloading valve, so that the pressure self-control device can automatically switch the pressure adding and releasing modes according to the real-time pressure value, automatically adjust the pressure adding and releasing speed and realize the whole-course automatic operation.

The invention also provides a control method of the pressure self-control device, which comprises the following steps:

step one, obtaining a target pressure value F _d Parameter information; the control unit reads the pressure value of the detection unit in real time and calculates the real-time pressure value F of the execution unit according to the conversion coefficient of the execution unit _t ；

Step two, determining a pressurizing or pressure relief mode;

step three, determining a control stage of pressurization or depressurization according to the calculation result of the calculation formula (1), executing the staged pressurization or staged depressurization operation, continuously acquiring a real-time pressure value in the execution process,

wherein B is the ratio of the error between the real-time pressure value and the target pressure value to the target pressure value;

step four, maintaining the target pressure value F _d The time required to maintain the real-time pressure value F _t At the target pressure value F _d Within a specified threshold e of: if the threshold value is not within the range of the specified threshold value e, repeating the third step; if the pressure value is within the specified threshold value e, the real-time pressure value F is maintained _t Within a prescribed threshold e rangeAnd (3) inner part.

According to the real-time pressure value obtained by the detection unit and the target pressure value conversion result, the pressure adding and releasing mode is determined, different pressure control stages are determined, the rotating speed of the driving unit is correspondingly adjusted, and then the oil outlet speed of the hydraulic oil of the oil pump is changed, so that the pressure self-control device can automatically perform staged pressurization or staged pressure release, and the pressure control efficiency and the accuracy are both considered; meanwhile, the pressure condition in the execution unit is detected in real time, and accurate pressurization or pressure relief operation is automatically carried out on the pressure value exceeding the precision range, so that the real-time pressure value and the target pressure value are always kept within the required precision range, and the testing efficiency and the accuracy of the testing result are greatly improved.

Specifically, when B <0, opening the loading valve, and controlling the pressure by the control unit to carry out graded pressurization from the control device; and when B >0, opening the unloading valve, and controlling the pressure to release pressure in a grading way by the control unit.

Specifically, the staged pressurization or staged depressurization operation is as follows:

when B is less than or equal to-20% or B is more than or equal to 20%, the driving unit is modulated to rotate at full speed, and the real-time pressure value F is read at certain intervals _t Using the current real-time pressure value F _t(n+1) Subtracting the last real-time pressure value F _tn Obtaining the rate of change of pressure

n is a natural number more than or equal to 1; every calculation of a certain number of pressure change rates +.>

And calculate a first mean pressure change value +.>

With real-time pressure value F _t Continuously using the first mean pressure change value +.>

Updating full-speed average pressure changesValue D of _All-around ；

When-20%<B is less than or equal to-10% or less than or equal to B<When 20%, the corresponding valve is kept open, the driving unit is modulated to half-speed rotation, and a second average pressure change value when the driving unit rotates at half-speed is calculated in the same way as the step 1

And calculating a first average pressure variation value according to the calculation formula (2)>

And a second mean pressure variation value +.>

Updating the full-speed average pressure change value D as a result of the average of (a) _All-around ，

When-10% < B < - > e| or |e| < B <10%, the rotational speed of the driving unit is set according to the calculation formula (3),

wherein:

v is the rotational speed of the drive unit,

F _d for the target pressure value, V _All-around For a speed value at which the drive unit rotates at full speed,

the term "absolute value" is used to denote the absolute value,

e represents a prescribed threshold;

when the- |e| is less than or equal to B|e|, stopping the driving unit to work, closing the loading valve and the unloading valve, stopping the driving unit to rotate, and maintaining the pressure value at the moment; if the pressure is 10 percent less than B < -e| in the maintaining process, opening a loading valve, and starting a driving unit to pressurize by calculating the rotating speed obtained in the formula (3); if 10% > B > |e| is maintained, opening an unloading valve, and opening the driving unit to release pressure at the rotating speed obtained in the calculation formula (3).

In order to achieve the accuracy and efficiency of the pressurization process, in particular the staged pressurization comprises the following steps:

when B is less than or equal to-20%, the loading valve is opened, the driving unit is modulated to rotate at full speed, and the real-time pressure value F is read at certain intervals _t Current real-time pressure value F _t(n+1) Subtracting the last real-time pressure value F _tn Obtaining the rate of change of pressure

n is a natural number greater than or equal to 1, and the pressure change rate is calculated by a certain amount>

Then a first mean pressure variation value +. >

Updating full-speed average pressure change value D _All-around ；

As the pressurization proceeds, when-20%<B is less than or equal to-10%, at the moment, the loading valve is kept open, the driving unit is modulated to half-speed rotation, and a second average pressure change value when the driving unit rotates at half-speed is calculated in the same way as the step 1

And a second mean pressure variation value +.>

Updating the full-speed average pressure change value D as a result of the average of (a) _All-around ；

As the pressurization proceeds, when-10% < B < -e|, the rotational speed of the driving unit is set according to the calculation formula (3).

Along with the continuous progress of the pressurization, when the E is less than or equal to B is less than or equal to E, the operation of the driving unit is stopped, the loading valve is closed, stopping the rotation of the driving unit, and maintaining the current real-time pressure value within the range according to the time required by the target pressure value; if 10% > B > |e| is maintained, opening an unloading valve, and opening the driving unit to release pressure at the rotating speed obtained in the calculation formula (3).

In order to achieve the accuracy and efficiency of the pressure relief process, in particular the staged pressure relief comprises the following steps:

When B is more than or equal to 20%, opening an unloading valve, modulating the driving unit to rotate at full speed, and reading a real-time pressure value F at certain intervals _t Using the current real-time pressure value F _t(n+1) Subtracting the last real-time pressure value F _tn Obtaining the rate of change of pressure

And calculate a first mean pressure change value +.>

Updating full-speed average pressure change value D _All-around ；

With the continuous progress of pressure relief, when the B is 10 percent or less<When 20%, the unloading valve is kept open, the driving unit is modulated to rotate at half speed, and the first step of calculating the half speed rotation of the driving unit is the same as the first step of 1Average pressure change value

And a second mean pressure variation value +.>

Updating the full-speed average pressure change value dbfull as a result of the average of (a);

as the pressure relief continues, when |e| < B <10%, the rotational speed of the driving unit is set according to the calculation formula (3);

when the pressure relief is continuously carried out and the temperature of the pressure-bearing valve is less than or equal to B and less than or equal to E, stopping the working of the driving unit, closing the unloading valve, stopping the rotation of the driving unit, and maintaining the current real-time pressure value within the range according to the time required by the target pressure value; if the pressure is 10 percent less than B < -e| in the maintaining process, opening the loading valve, and starting the driving unit to pressurize by calculating the rotating speed obtained in the formula (3).

Further, in the second step, the control terminal (for example, a computer or a mobile phone) transmits a command capable of pressurizing or depressurizing, and if the control command transmitted by the control terminal does not accord with the actual situation, the control unit compares the calculation formula (1) with a prescribed threshold e, and controls the pressure automatic control device to execute the pressurizing or depressurizing operation.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, a high-flow pressure self-control device is used, and an innovative pressure control method is combined, so that a control strategy and a control stage can be automatically adjusted according to the conversion result of a real-time pressure value and a target pressure value, and the rotation speed of a direct-current motor is correspondingly adjusted so as to change the oil outlet speed of an oil pump, thereby realizing automatic staged pressurization and staged pressure relief of the pressure self-control device and achieving both the efficiency and the accuracy of pressure control; meanwhile, the pressure condition in the execution unit is detected in real time, and accurate pressurization or pressure relief operation is automatically carried out on the pressure value exceeding the precision range, so that the real-time pressure value is ensured to be kept within the precision range specified by the target pressure value, and the test efficiency and the accuracy of the test result are greatly improved.

2. The pressure self-control device has a simple structure and is very convenient to install on site; the whole pressure control process is automatically carried out without human intervention, and the control process is sent to an upper computer such as a mobile phone or a computer for monitoring in real time, so that the operation process is convenient and quick.

3. The invention can use the storage battery to supply power, and can meet the severe working environments such as no electricity or power failure in a static load test site.

Drawings

FIG. 1 is a schematic diagram of the working principle of a pressure self-control device in the prior art;

FIG. 2 is a schematic diagram of the overall structure of a medium-pressure self-control device according to the present invention;

FIG. 3 is a schematic diagram of a pressurizing process of a medium-pressure self-control device according to the present invention;

FIG. 4 is a schematic diagram of a pressure relief process of a self-control device for pressure relief in accordance with an embodiment of the present invention;

FIG. 5 is a flow chart of a control method of the pressure self-control device in the second embodiment of the invention;

FIG. 6 is a flow chart of a method for controlling a pressurization process of a two-pressure self-control device according to the present invention;

FIG. 7 is a flow chart of a method for controlling a pressure relief process of a two-pressure self-control device according to the present invention;

in the figure: 1. a soil layer; 2. a foundation pile; 3. a load supporting frame; 4. a load; 5. a hydraulic jack; 6. a power supply; 7. an oil storage tank; 8. a DC motor; 9. an oil pump; 10. a three-way valve; 11. a second one-way valve; 12. unloading the valve; 13. loading a valve; 14. a first one-way valve; 15. an oil outlet pipe branches; 16. an oil return pipeline; 17. an oil outlet pipeline; 18. an oil pressure sensor; 19. and a control unit.

Detailed Description

The following description of the embodiments of the present invention will be made more apparent and fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by one of ordinary skill in the art without undue burden on the person of ordinary skill in the art based on embodiments of the present invention, are within the scope of the present invention.

Example 1

As shown in fig. 2, the present embodiment provides a pressure self-control device for foundation pile static load test, which comprises a control unit 19, a valve assembly, a driving unit, a power supply 6 unit, a detection unit, an oil storage tank 7, an oil outlet pipe 17, an oil return pipe 16 and an execution unit, wherein the valve assembly comprises a loading valve 13 and an unloading valve 12; the driving unit, the detecting unit, the loading valve 13 and the unloading valve 12 are all in communication or electrically connected with the control unit 19; the output end of the driving unit is connected with the input end of the oil pump 9, the driving unit drives the oil pump 9 to synchronously rotate, and the control unit 19 controls the rotating speed of the driving unit; one end of an oil inlet pipe of the oil pump 9 is connected with the oil storage tank 7, and the other end of the oil inlet pipe is selectively connected with the oil outlet pipe 17 and the oil return pipe 16; the oil outlet pipeline 17 is connected with the oil inlet end of the execution unit, an oil outlet pipeline branch 15 is connected to the oil outlet pipeline 17, and the oil outlet pipeline branch 15 is connected with the oil storage tank 7 through an unloading valve 12; the oil return pipeline 16 is connected with an oil outlet end of the execution unit, an oil return pipe branch is connected between the oil return pipeline 16 and the execution unit, and the oil return pipe branch is connected with the oil storage tank 7 through the loading valve 13; the detection unit is arranged on the oil outlet pipeline 17 and is used for measuring the oil pressure in the oil outlet pipeline in real time; the power supply 6 provides electrical energy to the device.

Preferably, the loading valve 13 and the unloading valve 12 can be electromagnetic valves, so that the control is convenient and the stability is high.

Specifically, the driving unit is a direct current motor 8, a three-way valve 10 is arranged in the oil pump 9, an oil inlet pipe is selectively connected with an oil outlet pipe 17 or an oil return pipe 16 through the three-way valve 10, and the executing unit is a hydraulic jack 5.

Further, a first one-way valve 14 is arranged on an oil outlet pipeline 17 between the three-way valve 10 and the hydraulic jack 5, and the first one-way valve 14 prevents hydraulic oil from reversely flowing into an oil outlet of the oil pump 9; the second one-way valve 11 is arranged on the oil return pipeline 16 between the three-way valve 10 and the hydraulic jack 5, and the second one-way valve 11 can prevent hydraulic oil from reversely flowing into the oil outlet of the oil pump 9.

Specifically, the detection unit is provided as an oil pressure sensor 18, the oil outlet pipe 17 is connected to the oil outlet pipe branch 15 through a three-way joint, and the oil pressure sensor 18 is mounted on the three-way joint.

Specifically, the control unit 19 is in communication with or electrically connected to the dc motor 8, and a motor speed adjusting module is disposed on the control unit 19, and the motor speed adjusting module can adjust the rotation speed of the dc motor 8. The rotating shaft of the direct current motor 8 is fixedly connected with the rotating shaft of the oil pump 9 through a fastening piece (such as a screw), so that the oil pump 9 is driven to synchronously rotate when the direct current motor 8 rotates; the oil inlet of the oil pump 9 is connected with the oil storage tank 7, hydraulic oil is filled in the oil storage tank 7, and when the oil pump 9 rotates, the hydraulic oil in the oil storage tank 7 flows into the oil pump 9. The inside of the oil pump 9 is provided with a three-way valve 10, hydraulic oil selectively flows into an oil outlet pipeline 17 or an oil return pipeline 16 through the three-way valve 10, the oil outlet pipeline 17 is connected with a lower oil tank joint of the hydraulic jack 5, the oil return pipeline 16 is connected with an upper oil tank joint of the hydraulic jack 5, a first one-way valve 14 is arranged on the oil outlet pipeline 17 between the three-way valve 10 and the hydraulic jack 5, and the first one-way valve 14 can prevent the hydraulic oil from reversely flowing into an oil outlet of the oil pump 9; the second one-way valve 11 is arranged on the oil return pipeline 16 between the three-way valve 10 and the hydraulic jack 5, the second one-way valve 11 can prevent hydraulic oil from reversely flowing into the oil outlet of the oil pump 9, the oil outlet pipeline 17 between the first one-way valve 14 and the hydraulic jack 5 is connected with the oil outlet pipeline branch 15, the oil outlet pipeline branch 15 is connected with the oil storage tank 7, and the unloading valve 12 is arranged on the oil outlet pipeline branch 15. An oil return pipe branch is connected to an oil storage tank 7 through an oil return pipe 16 between the second check valve 11 and the hydraulic jack 5, and a loading valve 13 is arranged on the oil return pipe branch. The loading valve 13 and the unloading valve 12 are electromagnetic valves and are in communication or electrically connected with a control unit 19. The three-way joint is arranged on the oil outlet pipeline 17 between the first check valve 14 and the hydraulic jack 5, the oil pressure sensor 18 can be screwed on the three-way joint, the oil pressure sensor 18 is in communication connection with the control unit 19, the oil pressure sensor 18 measures the pressure of hydraulic oil in the oil pipeline 17 in real time and feeds back the pressure value to the control unit 19, the control unit 19 is provided with a microprocessor unit, the real-time load pressure borne by the hydraulic jack 5 can be calculated according to the real-time pressure value and the conversion coefficient of the hydraulic jack 5, the power supply 6 (which can be a storage battery or other forms of power supply) is electrically connected with the control unit 19, and the control unit 19 is provided with a power supply conversion circuit for converting the electric energy provided by the power supply 6 into various power supplies required by the device.

The control unit 19 is provided with a wireless communication module that receives a target pressure value transmitted from a control terminal (e.g., a cellular phone or a computer) and a time for maintaining the pressure through a wireless signal, and the wireless communication module can use a communication frequency of 433 MHz. The control unit 19 calculates a real-time pressure value and judges whether to pressurize or depressurize based on a difference between the real-time pressure value and a target pressure value.

As shown in fig. 3, when pressurizing, the three-way valve 10 is selected to be connected to the oil outlet pipeline 17, the loading valve 13 is controlled to be opened, then the direct current motor 8 is started, the direct current motor 8 rotates to drive the oil pump 9 to absorb oil, at the moment, hydraulic oil flows into the lower oil tank of the hydraulic jack 5 through the oil outlet pipeline 17, the oil quantity of the lower oil tank of the hydraulic jack 5 is increased, the liquid pressure in the lower oil tank is increased, the top head of the hydraulic jack 5 is pushed to extend outwards, the hydraulic oil in the oil tank on the hydraulic jack 5 is extruded, and flows out through the oil return pipeline 16, so that the loading valve 13 is opened, and the hydraulic oil flows back to the oil storage tank 7 through the loading valve 13.

As shown in fig. 4, when the pressure is relieved, the three-way valve 10 is selected to be connected to the oil return pipeline 16, the unloading valve 12 is controlled to be opened, then the direct current motor 8 is started, the direct current motor 8 rotates to drive the oil pump 9 to absorb oil, at the moment, hydraulic oil flows into the upper oil tank of the hydraulic jack 5 through the oil return pipeline 16, the oil quantity of the upper oil tank of the hydraulic jack 5 is increased, the liquid pressure in the upper oil tank is increased, the jack of the hydraulic jack 5 is pushed to shrink inwards, the hydraulic oil of the lower oil tank of the hydraulic jack 5 is extruded, and flows out through the oil outlet pipeline 17, so that the unloading valve 12 is opened, and the hydraulic oil flows back to the oil storage tank 7 through the unloading valve 12.

Further, the control unit 19 comprises a memory for storing program code and various data, which may be provided as Read Only Memory (ROM), random Access Memory (RAM), programmable Read Only Memory (PROM) or any other storage medium readable by a computer for carrying or storing data.

The control unit 19 may take the form of a combination including one or more Central Processing Units (CPU), MPU, microprocessor, digital processing chip, and various control chips, etc., and the control unit 19 connects the dc motor 8, the unloading valve 12, the loading valve 13, and the detection unit using various interfaces and lines, and the control unit 19 performs the functions of controlling the opening and closing of the dc motor 8, the unloading valve 12, and the loading valve 13 by running or executing a program or module stored in a memory of the control unit 19 and storing data during execution, and by calling the data stored in the memory, thereby realizing the functions of controlling the opening and closing of the dc motor 8, the unloading valve 12, and the loading valve 13 by the control unit 19, and meeting the requirement of the control unit 19 for processing the data.

Further, the control unit 19 is in wireless communication with the control terminal, preferably, the control terminal may be configured as a wireless remote controller or a mobile terminal (for example, a smart phone, a smart tablet computer, etc.), a wireless communication module is connected to a connection interface (for example, a USB interface) on the control terminal to wirelessly communicate with the control unit 19, the control terminal is installed with static load test software (the static load test software is usually used in the art and only needs to meet the requirements of the present invention) commonly used in the prior art, and before the static load test is started, parameter values such as test specifications, loading stages, unloading stages, a maximum target pressure value, etc. are selected on the static load test software, then the static load test software automatically sends a pressurization or depressurization command, and the pressure for the foundation pile static load test receives command information from the control device and automatically performs pressurization or depressurization operation.

Embodiment two:

the invention also provides a control method of the pressure self-control device, which is shown in fig. 5-7. Static load test software is installed on the control terminal (mobile phone or computer),before starting the static load test, selecting test specifications, loading stages, unloading stages and target pressure value F on the static load test software _d And the control unit 19 automatically switches the pressurizing or depressurizing modes according to the real-time pressure value, adjusts the rotating speed of the direct current motor 8 according to different pressure control stages, and changes the oil outlet speed of the hydraulic oil of the oil pump 9, thereby automatically adjusting the pressurizing and depressurizing speed. The control method provided by the invention does not need manual operation in the whole process, greatly improves the testing efficiency, has extremely high pressure control precision, and achieves the balance of the pressure control efficiency and the precision. The control process of the control method of the invention is as follows:

step one, the control unit 19 reads the pressure value of the detection unit in real time, and calculates the real-time pressure value F of the execution unit according to the conversion coefficient of the execution unit _t ；

Step two, determining a pressurizing or pressure relief mode;

step four, maintaining the target pressure value F _d The time required to maintain the real-time pressure value F _t Within a prescribed threshold e: - |e| is less than or equal to B and less than or equal to |e|: if the pressure value is not within the range of the specified threshold value e, repeating the third step, and if the pressure value is within the range of the specified threshold value e, maintaining the real-time pressure value F _t Within a prescribed threshold e.

The specified threshold e represents an error range value, namely precision, of allowable fluctuation, can be set in a self-defined mode according to actual working condition requirements, and can also adopt an error range value common to industries.

By the control method, different pressure control stages can be determined according to the difference value between the real-time pressure value and the target pressure value, and the pressure self-control device can be controlled to automatically perform graded pressurization or graded pressure relief, so that the pressurization and pressure relief efficiency is improved, and the pressure is accurately controlled; meanwhile, the pressure in the hydraulic jack 5 can be detected in real time, and the automatic accurate pressurization and pressure relief operation is carried out on the pressure value exceeding the precision range according to the control method, so that the actual pressure value and the target pressure value are ensured to be kept within a certain precision range, and the testing efficiency and the precision of the testing result are greatly improved.

Further, in the second step, if the control command sent by the control terminal (e.g. computer or mobile phone) does not match the actual situation, the control unit 19 compares the control command with the predetermined threshold e according to the calculation formula (1) to control the pressure self-control device to perform the pressurizing or depressurizing operation, preferably, if the pressurizing and depressurizing command sent by the control terminal (e.g. computer or mobile phone) is opposite to the actual situation, the pressurizing target pressure value F is received _d But is provided with

The pressure relief operation is performed by adopting the pressure relief step; receiving the pressure relief target pressure value F _d But->

The pressurizing operation is performed by adopting the pressurizing step described above.

The specific staged pressurization process is as follows: when the ratio B <0 of the error between the real-time pressure value and the target pressure value to the target pressure value, the control unit 19 controls the pressure self-control device to perform pressurization:

opening a loading valve 13 and starting the direct current motor 8;

continuously acquiring a real-time pressure value, determining a control stage according to the value B,

as shown in FIG. 6, when B is less than or equal to-20%, the DC motor 8 is modulated to 100% speed, namely full speed rotation, and the real-time pressure value F is read every certain time _t Using the current real-time pressure value F _t(n+1) Subtracting the last real-time pressure value F _tn Obtaining the rate of change of pressure

Every calculation of a certain number of pressure change rates +. >

And calculate a first average pressure change value

Updating full-speed average pressure change value D _All-around 。

Specifically, the real-time pressure value F is read every 10 milliseconds _t And respectively mark it as F _t1 、F _t2 、F _t3 ……F _t(n+1) The current real-time pressure value is used for subtracting the last real-time pressure value to obtain the pressure change rate, which are respectively recorded as

I.e. < ->

n is a natural number of 1 or more, that is, < >>

Representing the rate of pressure change every 10 milliseconds. Every 10 pressure change rates are calculated, the pressure change rates are ordered from small to large, then the maximum value and the minimum value are removed, the rest values are added, and the added sum is divided by 8, so that a first average pressure change value +.>

First mean pressure variation value->

Indicating the average rate of pressure change per 10 milliseconds for full speed operation of the dc motor 8; along withReal-time pressure value F _t Is calculated every new 10 pressure change rates +.>

Then update the first average pressure change value +.>

Use->

Updating full-speed average pressure change value D _All-around ；

As the pressurization proceeds, when-20%<When B is less than or equal to-10%, the direct current motor 8 is modulated to 50% speed, namely half-speed rotation, the current real-time pressure value is used for subtracting the last real-time pressure value to obtain the pressure change rate, and a second average pressure change value when the direct current motor 8 rotates at half-speed is calculated

And calculating a first average pressure change value according to the following calculation formula (2)

And a second mean pressure variation value +.>

Updating the full-speed average pressure change value D as a result of the average of (a) _All-around The method comprises the steps of carrying out a first treatment on the surface of the With constant reading of the real-time pressure value +.>

Continuously updating D _All-around And is also updated continuously.

As the pressurization proceeds, when-10% < B < -e|, the rotation speed of the direct current motor 8 is set according to the following calculation formula (3),

wherein:

v is the rotational speed of the dc motor 8,

F _d for the target pressure value, V _All-around Is the value of the speed at which the dc motor 8 rotates at full speed,

the term "absolute value" is used to denote the absolute value,

e denotes a prescribed threshold.

As the pressurization continues, if- |e|b|e| is smaller than or equal to b| the operation of the direct current motor 8 is stopped, the loading valve 13 is closed, and the current real-time pressure value is maintained within this range for the time required to maintain the target pressure value.

As the pressurization proceeds, if 10% > B > |e| is performed, the unloading valve 12 is opened, and the dc motor 8 is turned on at the rotation speed obtained by the calculation formula (3) to perform pressure relief.

The specific staged pressure relief process is as follows: a ratio B of the error between the real-time pressure value and the target pressure value to the target pressure value>0, explaining the real-time pressure value F _t Greater than the target pressure value F _d The control unit 19 controls the pressure self-control device to perform a pressure relief operation:

Opening an unloading valve 12 and starting a direct current motor 8;

as shown in FIG. 7, when B is more than or equal to 20%, the DC motor 8 is modulated to rotate at full speed, and the real-time pressure value F is read at intervals _t Using the current real-time pressure value F _t(n+1) Subtracting the last real-time pressure value F _tn Obtaining the rate of change of pressure

And calculate to obtain the firstAverage pressure change value>

Updating full-speed average pressure change value D _All-around ；

Specifically, the real-time pressure value F is read every 10 milliseconds _t And respectively mark it as F _t1 、F _t2 、F _t3 ……F _t(n+1) And subtracting the last real-time pressure value from the current real-time pressure value, respectively recorded as

I.e.

That is to say +>

Representing the rate of pressure change every 10 milliseconds, sequencing from small to large for every 10 rates of pressure change calculated, then removing the maximum and minimum values, adding the remaining values, and dividing the added sum by 8 to obtain a first average pressure change value +.>

First mean pressure variation value->

Indicating the average rate of pressure change per 10 milliseconds for full speed operation of the dc motor 8; with real-time pressure value F _t Is calculated every new 10 pressure change rates +.>

Then use the first mean pressure change value +.>

Updating the full-speed average pressure change value D _All-around ；

With the continuous progress of pressure relief, when the B is 10 percent or less<When 20%, the unloading valve 12 is kept open, the direct current motor 8 is modulated to half-speed rotation, and a second average pressure change value when the direct current motor 8 rotates at half-speed is calculated in the same way as the step 1

And calculates a first average pressure variation value +_ according to the following expression (2)>

And a second mean pressure variation value +.>

As the pressure relief continues, at this time, if |e| < B <10%, the rotational speed of the dc motor 8 is set according to the calculation formula (3);

wherein:

v is the rotational speed of the dc motor 8,

F _d as a result of the value of the target pressure,

V _all-around Is the value of the speed at which the dc motor 8 rotates at full speed,

the term "absolute value" is used to denote the absolute value,

e represents a prescribed threshold;

with the continuing progress of the pressure relief, when- |e|b|e| is smaller than or equal to b|e|, the operation of the direct current motor 8 is stopped, the unloading valve 12 is closed, maintaining the current real-time pressure value within the range in terms of the time required to maintain the target pressure value; in the maintaining process, if-10% < B < -e|, the loading valve 13 is opened, and the direct current motor 8 is started to pressurize at the rotating speed obtained by the calculation formula (3).

Normally, the pressurization or depressurization steps are continuously performed. However, in the actual test process, various unknown reasons such as power failure may exist, so that the device stops working, while the hydraulic jack 5 still maintains the pressure at the moment before power failure, when the device is to work normally again, the control stage where the pressure self-control device is actually located is determined by calculating the value B, and the pressurization or pressure relief operation is continuously performed according to the control stage, that is, the operation is continuously performed according to the state before the pressure self-control device stops working.

Although embodiments of the present 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 therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The pressure self-control device for the foundation pile static load test comprises a control unit, a valve assembly, a driving unit, a power supply, a detection unit, an oil storage tank, an oil outlet pipeline, an oil return pipeline and an execution unit, and is characterized in that the valve assembly comprises a loading valve and an unloading valve; the driving unit, the detecting unit, the loading valve and the unloading valve are all connected with the control unit; the output end of the driving unit is connected with the input end of the oil pump, the driving unit drives the oil pump to synchronously rotate, and the control unit controls the rotating speed of the driving unit; one end of the oil inlet pipe of the oil pump is connected with the oil storage tank, and the other end of the oil inlet pipe is selectively connected with the oil outlet pipe and the oil return pipe; the oil outlet pipeline is connected with the oil inlet end of the execution unit, an oil outlet pipeline branch is connected to the oil outlet pipeline, and the oil outlet pipeline branch is connected with the oil storage tank through an unloading valve; the oil return pipeline is connected with an oil outlet end of the execution unit, an oil return pipeline branch is connected between the oil return pipeline and the execution unit, and the oil return pipeline branch is connected with the oil storage tank through a loading valve; the detection unit is arranged on the oil outlet pipeline and is used for measuring the oil pressure in the oil outlet pipeline in real time; the power supply provides electrical energy to the device.

2. The pressure self-control device for foundation pile static load test according to claim 1, wherein a three-way valve is arranged in the oil pump, an oil inlet pipe is selectively connected with an oil outlet pipe or an oil return pipe through the three-way valve, and the execution unit is a hydraulic jack.

3. The pressure self-control device for foundation pile static load test according to claim 2, wherein a first one-way valve is arranged on an oil outlet pipeline between the three-way valve and the hydraulic jack, and the first one-way valve prevents hydraulic oil from reversely flowing into an oil outlet of the oil pump; and a second one-way valve is arranged on the oil return pipeline between the three-way valve and the hydraulic jack, and the second one-way valve can prevent hydraulic oil from reversely flowing into an oil outlet of the oil pump.

4. The pressure self-control device for foundation pile static load test according to claim 2, wherein the detection unit is provided as an oil pressure sensor, the oil outlet pipe is connected with the oil outlet pipe branch through a three-way joint, and the oil pressure sensor is mounted on the three-way joint.

5. A control method of a pressure self-controlling device for foundation pile static load test according to any one of claims 1 to 4, characterized by comprising the steps of:

Step two, determining a pressurizing or pressure relief mode;

step four, maintaining the target pressure value F _d The time required to maintain the real-time pressure value F _t Within a prescribed threshold e: if the threshold value is not within the range of the specified threshold value e, repeating the third step; if the pressure value is within the specified threshold value e, the real-time pressure value F is maintained _t Within a prescribed threshold e.

6. The control method of a pressure self-control device for foundation pile static load test according to claim 5, wherein when B <0, the loading valve is opened, and the control unit controls the pressure self-control device to perform staged pressurization; and when B >0, opening the unloading valve, and controlling the pressure to release pressure in a grading way by the control unit.

7. A control method of a pressure self-controlling device for foundation pile static load test according to claim 6, characterized in that the step pressurization or step depressurization operation is as follows:

And calculate a first mean pressure change value +.>

Updating full-speed average pressure change value D _All-around ；

And a second mean pressure variation value +.>

Wherein:

v is the rotational speed of the drive unit,

the term "absolute value" is used to denote the absolute value,

e represents a prescribed threshold;

8. A control method of a pressure self-control device for foundation pile static load test according to claim 7, characterized in that the specific staged pressurization process is as follows:

Then a first mean pressure variation value +. >

Updating full-speed average pressure change value D _All-around ；

And a second mean pressure variation value +.>

As the pressurization proceeds, when-10% < B < -e|, the rotational speed of the driving unit is set according to the calculation formula (3);

along with the continuous progress of pressurization, when the- |e| is less than or equal to B|e|, stopping the working of the driving unit, closing the loading valve, stopping the rotation of the driving unit, and maintaining the pressure value at the moment; if 10% > B > |e| is maintained, opening an unloading valve, and opening the driving unit to release pressure at the rotating speed obtained in the calculation formula (3).

9. The control method of a pressure self-control device for foundation pile static load test according to claim 7, characterized in that the specific staged pressure relief process is as follows:

When B is more than or equal to 20%, opening an unloading valve, modulating a driving unit to rotate at full speed, and reading a real-time pressure value F at certain intervals _t Using the current real-time pressure value F _t(n+1) Subtracting the last real-time pressure value F _tn Obtaining the rate of change of pressure

And calculate a first mean pressure change value +.>

Updating full-speed average pressure change value D _All-around ；

With the continuous progress of pressure relief, when the B is 10 percent or less<When 20%, the unloading valve is kept open, the driving unit is modulated to half-speed rotation, and a second average pressure change value of the driving unit during half-speed rotation is calculated in the same way as in the step 1

And a second mean pressure variation value +.>

when the pressure relief is continuously carried out and the temperature of the pressure-bearing valve is not more than B and not more than E, stopping the working of the driving unit, closing the unloading valve, stopping the rotation of the driving unit and maintaining the pressure value at the moment; if the pressure is 10 percent less than B < -e| in the maintaining process, opening the loading valve, and starting the driving unit to pressurize by calculating the rotating speed obtained in the formula (3).

10. The method according to claim 5, wherein in the second step, the control terminal transmits a pressurization or depressurization command, and if the command transmitted by the control terminal does not match the actual situation, the control unit compares the calculation formula (1) with a predetermined threshold value e, and controls the pressure automatic control device to perform the pressurization or depressurization operation.