阅读说明：本技术 一种电磁式岩土工程超重力模拟装置及操作方法 (Electromagnetic type geotechnical engineering hypergravity simulation device and operation method ) 是由 李洪江 刘松玉 童立元 车鸿博 闫鑫 于 2020-06-10 设计创作，主要内容包括：本发明提供了一种电磁式岩土工程超重力模拟装置,包括电磁式超重力场发生机、供电系统和数控操作系统组成,电磁式超重力场发生机依靠上下两个对称等大的电磁铁产生集中分布、场强均匀的磁场,上下电磁铁的铁芯规格与线圈导线绕线匝数完全一致,上下线圈可以实现串联供电,也可独立供电,上下电磁铁外包裹磁屏蔽壳以消除环境磁场的影响。磁场强度由供电系统的供电电流大小及线圈绕线匝数控制,上部电磁铁可通过数控系统控制轴承转动而调节高度,试验操作台位于两个电磁铁形成的匀强磁场中,采用土样中配掺磁粉的方式,从而在场强梯度变化时获得磁力作用。本装置电磁诱导的超重力场稳定、易于操作和推广使用。(The invention provides an electromagnetic type geotechnical engineering hypergravity simulation device which comprises an electromagnetic type hypergravity field generator, a power supply system and a numerical control operating system, wherein the electromagnetic type hypergravity field generator generates a magnetic field with concentrated distribution and uniform field intensity by virtue of an upper electromagnet and a lower electromagnet which are symmetrical and the like, the specifications of iron cores of the upper electromagnet and the lower electromagnet are completely consistent with the number of turns of a coil wire, the upper coil and the lower coil can realize series power supply and can also independently supply power, and the upper electromagnet and the lower electromagnet are wrapped with a magnetic shielding shell to eliminate the influence of an environmental. The magnetic field intensity is controlled by the supply current of a power supply system and the number of turns of a coil winding, the upper electromagnet can control the bearing to rotate through a numerical control system to adjust the height, the test operating platform is positioned in a uniform magnetic field formed by the two electromagnets, and a mode of mixing magnetic powder in a soil sample is adopted, so that the magnetic action is obtained when the field intensity gradient changes. The device has stable electromagnetic induction supergravity field and is easy to operate, popularize and use.)

1. The utility model provides an electromagnetic type geotechnical engineering hypergravity analogue means which characterized in that: the system comprises an electromagnetic type hypergravity field generator (1), a power supply system (2) and a numerical control operation system (3); the electromagnetic type super-gravity field generator (1) is fixed on the rigid support frame (12); the main component of the electromagnetic type hypergravity field generator (1) is composed of an upper electromagnet (4) and a lower electromagnet (5) which are symmetrical and equal in size, and can generate magnetic fields which are distributed in a concentrated manner and uniform in field intensity in the space domain of the upper electromagnet (4) and the lower electromagnet (5); the surfaces of the upper and lower magnets (4, 5) are respectively wound with upper and lower coils (7, 8); the upper and lower electromagnets (4, 5) are provided with internal iron cores (6); the magnetic field intensity is controlled by the power supply current of the power supply system (2) and the number of turns of the windings of the upper coil (7) and the lower coil (8); the outer layers of the upper electromagnet (4) and the lower electromagnet (5) are respectively wrapped with an upper magnetic shielding shell (10) and a lower magnetic shielding shell (11); the numerical control operating system (3) comprises a computer and a display; the computer controls the input current of the upper and lower electromagnets (4, 5) through the magnetic field measured by the gauss meter (14); the test operation platform (9) is positioned in a uniform magnetic field formed by the upper electromagnet (4) and the lower electromagnet (5), and a soil sample is mixed with magnetic powder on the test operation platform, so that a supergravity simulation effect based on gradient magnetic force loading of an electromagnetic field is obtained after the magnetic powder is saturated and magnetized.

2. The electromagnetic geotechnical engineering hypergravity simulation device according to claim 1, wherein: the specifications of the upper electromagnet and the lower electromagnet (4, 5) can be selected according to different geotechnical engineering test requirements and sample test scales.

3. The electromagnetic geotechnical engineering hypergravity simulation device according to claim 1, wherein: the specification of each internal iron core (6) and the number of turns of wire windings of the corresponding upper coil (7) and the corresponding lower coil (8) are completely consistent, and the upper coil (7) and the lower coil (8) are controlled by the power supply system (2) to realize series power supply and independent power supply.

4. The electromagnetic geotechnical engineering hypergravity simulation device according to claim 1, wherein: the inner iron cores (6) of the upper and lower electromagnets (4, 5) are made of soft iron materials, the electromagnets generate magnetic fields when being electrified, and the magnetic forces disappear after the power is cut off.

5. The electromagnetic geotechnical engineering hypergravity simulation device according to claim 1, wherein: the top of the upper electromagnet (4) is fixedly connected with a bearing (13); the other end of the bearing (13) penetrates through the top of the rigid support frame (12) and is fixedly connected with an electric motor (15); the numerical control operating system (3) controls the bearing (13) to rotate through the electric motor (15) so as to adjust the height of the upper electromagnet (4), and the magnetic field strength is ensured to be fully suitable for the heights of different test operating platforms (9).

6. The electromagnetic geotechnical engineering hypergravity simulation device according to claim 1, wherein: the power supply system (2) converts alternating current into direct current by means of a rectifier.

7. An operation method of an electromagnetic geotechnical engineering hypergravity simulation device is characterized in that: the method comprises the following steps:

step (1): preparing a soil sample in advance according to test requirements, doping a certain amount of magnetic powder into the soil sample, uniformly stirring, and placing the prepared sample on a test operation platform;

step (2): starting a power supply of a power supply system, controlling a bearing to rotate through a numerical control operating system to adjust the height of the upper electromagnet, and locking the height of the upper electromagnet after the distance between the upper electromagnet and the lower electromagnet meets the test condition;

and (3): an upper electromagnet and a lower electromagnet are connected in series to supply power, and the directions of the power supply currents of the upper coil and the lower coil are the same, so that uniform NS magnetic field intensity is generated in a test operation table area; measuring the magnetic field intensity through a gauss meter and feeding back to a computer in the numerical control operation system, and controlling the size of the input current of the coil by the computer to obtain a target field intensity; under the condition of sufficiently long electrifying time, until the magnetic powder on the test operating platform reaches saturation magnetization;

And (4): the mode of independent power supply of upper and lower electro-magnet is changed into, through control supply current size, can form different magnetic field modes:

big end up mode: the upper electromagnet has strong field and the lower electromagnet has small field;

or big-end-up mode: the upper electromagnet field intensity is small, and the lower electromagnet field intensity is strong;

or dynamic mode: the field intensity modes of the dynamic linear change of the field intensity of the upper electromagnet and the field intensity of the lower electromagnet;

according to the test requirement, the magnetic field directions of the upper electromagnet and the lower electromagnet can be changed by changing the current direction of the winding coil; different magnetic field forces can be generated on the magnetic powder of the sample by the gradient change of the field intensity, so that different stress modes can be simulated, and the additional magnetic force is applied to the sample to achieve the Ng supergravity simulation effect (1 g is a normal gravity environment, N >1 is supergravity, and N <1 is countergravity);

and (5): developing test contents on a test operation platform, completing a rock-soil body stability or rock-soil body-structure body interaction simulation test of a small-scale sample in a supergravity environment according to conventional operation, and obtaining a test result under a prototype size according to a similarity principle;

because the test platform is an open test operation platform, the test design can be adjusted by manual intervention in the test process;

And (6): and after the test is finished, cleaning the test operation platform, and sequentially closing the power supply of the numerical control operation system and the power supply system to keep the electromagnetic type hypergravity field generator clean and tidy.

8. The operating method of the electromagnetic geotechnical engineering hypergravity simulation device according to claim 7, wherein: the mixing ratio of the magnetic powder in the step (1) is determined by the test requirement, and is not less than 20%.

Technical Field

The invention relates to the field of geotechnical engineering test simulation, in particular to an electromagnetic type geotechnical engineering hypergravity simulation device and an operation method.

Background

Simulation of physical tests is an important technical approach for solving the problem of geotechnical engineering, and geotechnical engineering physical model tests generally comprise indoor model tests and Ng hypergravity model tests under the condition of 1 g. Geotechnical engineering involves large engineering scale, such as underground space excavation, high-soil and stone damming, high-rise building pile foundation and the like, and it is very difficult to accurately acquire the stability problem and the environmental safety problem caused by the engineering construction. A reasonable and accurate geotechnical engineering physical simulation device and simulation technology are indispensable. In the traditional sense, the 1g (normal gravity environment) test is limited by a test site, test expenses and the like, can only approximately show the geotechnical engineering test phenomenon on a small scale, and cannot accurately represent the real result of a large prototype test. Therefore, the Ng test becomes an important means for solving the physical simulation of large geotechnical engineering, and is widely recognized internationally. At present, a centrifugal machine which rotates at a high speed is depended on in an international Ng simulation test, and the centrifugal machine can generate centrifugal force on a rock and soil sample arranged in the centrifugal machine when rotating at the high speed to form a supergravity simulation effect of the Ng. According to a similar theory, a small-scale sample under the Ng hypergravity environment can be equivalent to a 1g condition prototype test effect under a corresponding proportion, and the conventional hypergravity centrifugal machine can realize the simulation of hundreds of gravitational acceleration (> 100 g), so that the waste on the scale of a model is effectively saved and avoided.

Although the application of the hypergravity centrifugal machine provides a powerful tool for geotechnical engineering physical simulation and promotes the development of the geotechnical physical simulation level, the hypergravity simulation formed by the centrifugal machine has long problems. Although well recognized, some of these problems have not been solved since the application of centrifuges to the field of geotechnical engineering. The three most important problems are: 1. the gravity field formed by the centrifugal acceleration of the centrifugal machine is not completely matched with the super gravity field, the centrifugal machine is influenced by the length of the rotating arm, and the gravity field of the rock and soil test in the test box is not uniform; 2. the centrifuge rotating at high speed cannot get rid of the disturbance and the uneven stress state change of the rock and soil sample in the test box in the two time stages of the initial rotation stage and the rotation stopping stage; 3. once the hypergravity centrifuge rotates, a tester can not manually adjust the test device any more, and only can use a manipulator with limited activity. The above problems severely limit the use efficiency of the supergravity centrifuge, and the centrifuge rotating at high speed has huge power consumption and high test cost. However, at present, a high-efficiency supergravity simulation technology and a replaceable device are still unavailable at home and abroad. Geotechnical engineering hypergravity simulation is still a big problem.

Disclosure of Invention

In order to solve the above problems, the present invention discloses the objects of: according to the principle that an electromagnetic field is equivalent to a gravity field, an electromagnetic type geotechnical engineering hypergravity simulation device and an operation method are provided.

The technical scheme is as follows: the invention provides

The system comprises an electromagnetic type hypergravity field generator, a power supply system and a numerical control operating system; the electromagnetic type hypergravity field generator is fixed on the rigid support frame; the main component of the electromagnetic type hypergravity field generator is an upper electromagnet and a lower electromagnet which are symmetrical and equal in size and can generate magnetic fields which are distributed in a concentrated mode and uniform in field intensity in the space domain of the upper electromagnet and the space domain of the lower electromagnet; the surfaces of the upper magnet and the lower magnet are respectively wound with an upper coil and a lower coil; the upper electromagnet and the lower electromagnet are provided with internal iron cores; the magnetic field intensity is controlled by the power supply current of the power supply system and the number of turns of the upper coil winding wire and the lower coil winding wire; the outer layers of the upper electromagnet and the lower electromagnet are respectively wrapped with an upper magnetic shielding shell and a lower magnetic shielding shell; the numerical control operating system comprises a computer and a display; the computer controls the input current of the upper electromagnet and the lower electromagnet according to the magnetic field measured by the gauss meter; and obtaining the stable target field intensity through real-time feedback. The test operation platform is positioned in a uniform magnetic field formed by the upper electromagnet and the lower electromagnet, and the test operation platform is provided with a mode of mixing the soil sample with the magnetic powder, so that a supergravity simulation effect based on electromagnetic field gradient magnetic force loading is obtained after the magnetic powder is saturated and magnetized.

Furthermore, the specifications of the upper electromagnet and the lower electromagnet can be selected according to different geotechnical engineering test requirements and sample test scales.

Furthermore, the specification of each internal iron core and the number of winding turns of the corresponding upper coil wire and the corresponding lower coil wire are completely consistent, and the upper coil wire and the lower coil wire are controlled by a power supply system to realize series power supply and independent power supply.

Furthermore, the inner iron cores of the upper electromagnet and the lower electromagnet are made of soft iron materials, a magnetic field is generated when the electromagnets are powered on, and the magnetic force disappears after the electromagnets are powered off.

Further, the top of the upper electromagnet is fixedly connected with the bearing; the other end of the bearing penetrates through the top of the rigid support frame and is connected and fixed with the electric motor; the numerical control operating system controls the bearing to rotate through the electric motor so as to adjust the height of the upper magnet, and the numerical control operating system is fully suitable for different heights of test operating tables under the condition of ensuring the uniformity and the strength of the magnetic field.

Further, the power supply system converts alternating current to direct current using a rectifier; the stability of the power supply current and the stability of the magnetic field intensity of the electromagnet in the test process are ensured.

Furthermore, the test operation platform is positioned in a uniform magnetic field formed by the upper electromagnet and the lower electromagnet, and the test operation platform is provided with a mode of mixing the soil sample with the magnetic powder, so that a supergravity simulation effect based on electromagnetic field gradient magnetic force loading is obtained after the magnetic powder is saturated and magnetized.

Furthermore, the numerical control operation system integrates digital display and computer operation functions, the computer controls the magnitude of the input current of the electromagnet according to the magnitude of the magnetic field measured by the gaussmeter, and stable target field intensity is obtained through real-time feedback.

An electromagnetic type geotechnical engineering hypergravity simulation device and an operation method thereof comprise the following steps:

step (1): preparing a soil sample in advance according to test requirements, adding a certain amount of magnetic powder (the magnetic powder adding ratio is determined by the test requirements and is not less than 20 percent in recommendation) into the soil sample, uniformly stirring, and placing the prepared sample on a test operation table;

step (2): and starting a power supply of a power supply system, controlling the bearing to rotate through the numerical control operating system to adjust the height of the upper electromagnet, and locking the height of the upper electromagnet after the distance between the upper electromagnet and the lower electromagnet meets the test conditions.

And (3) adopting a power supply mode of connecting the upper electromagnet and the lower electromagnet in series, and enabling the power supply current directions of the upper coil and the lower coil to be the same, so that uniform NS magnetic field intensity is generated in the area of the test operating platform. The magnetic field intensity is measured by a gauss meter and fed back to a computer in the numerical control operation system, and the computer controls the size of the input current of the coil so as to obtain the target field intensity. And (4) under the condition of sufficiently long electrifying time, until the magnetic powder on the test operating platform reaches saturation magnetization.

And (4) changing the power supply mode into an upper electromagnet independent power supply mode and a lower electromagnet independent power supply mode, and forming a field intensity mode with a strong upper electromagnet field and a small lower electromagnet field intensity (an upper big mode and a lower small mode), or a field intensity mode with a small upper electromagnet field and a strong lower electromagnet field (a upper small mode and a lower big mode), or a field intensity mode with dynamic linear changes of the field intensities of the upper electromagnet and the lower electromagnet (a dynamic mode). According to the test requirement, the magnetic field directions of the upper electromagnet and the lower electromagnet can be changed by changing the current direction of the winding coil. The gradient change of the field intensity can generate different magnetic field forces to the magnetic powder of the sample, so that different stress modes can be simulated, and the additional magnetic force is applied to the sample to achieve the Ng supergravity simulation effect (1 g is a normal gravity environment, N >1 is supergravity, and N <1 is antigravity).

And (5) developing test contents on a test operation platform, completing a rock-soil body stability or rock-soil body-structure body interaction simulation test of the small-scale sample in the hypergravity environment according to conventional operation, and obtaining a test result under the prototype size according to a similar principle. Because the test platform is an open test operation platform, the test design can be adjusted by manual intervention in the test process.

And (6) after the test is finished, cleaning the test operating platform, and sequentially closing the power supplies of the numerical control operating system and the power supply system to keep the electromagnetic type high gravity field generator clean and tidy.

Has the advantages that: the electromagnetic type geotechnical engineering hypergravity simulation device and the operation method provided by the invention have the following remarkable progress: the method solves the long-standing problem of difficulty in simulating the hypergravity of the geotechnical engineering and solves the problem that real-time manual intervention cannot be performed when the hypergravity is simulated by means of a high-speed rotating centrifuge. The device provides an electromagnetic field that is stable, can simulate different hypergravity field environment through changing current strength, and experimental easy operation easily masters and economic safety.

Drawings

FIG. 1 is an overall schematic view of an electromagnetic geotechnical engineering hypergravity simulation device according to the present invention;

FIG. 2 is a power supply circuit diagram of upper and lower electromagnets connected in series;

FIG. 3 is a diagram of independent power supply lines for upper and lower electromagnets;

fig. 4 is a schematic diagram of the principle of numerical control adjustment of magnetic field strength.

In the figure: 1-electromagnetic type hypergravity field generator, 2-power supply system, 3-numerical control operation system, 4-upper electromagnet, 5-lower electromagnet, 6-iron core, 7-upper coil, 8-lower coil, 9-test operation platform, 10-upper magnetic shielding shell, 11-lower magnetic shielding shell, 12-rigid support frame, 13-bearing, 14-gauss meter and 15-electric motor.

Detailed Description

The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the invention and not as limiting the scope of the invention. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

An electromagnetic type geotechnical engineering hypergravity simulation device is shown in figure 1 and comprises an electromagnetic type hypergravity field generator 1, a power supply system 2 and a numerical control operation system 3. The main component of the electromagnetic type hypergravity field generator 1 is an upper electromagnet 4 and a lower electromagnet 5 which are symmetrical and the like, and can generate magnetic fields which are distributed in a concentrated manner and have uniform field intensity in the space domains of the upper electromagnet 4 and the lower electromagnet 5. The electromagnetic type hypergravity field generator 1 is fixed on the rigid support frame 12, is a completely open system, and can adjust the test design in real time during the test.

The magnetic field intensity is controlled by the power supply current of the power supply system 2 and the number of turns of the upper and lower coils 7 and 8.

The specifications of the inner iron cores 6 of the upper electromagnets 4 and the lower electromagnets 5 and the numbers of winding turns of the upper coils 7 and the lower coils 8 are completely consistent, and the upper coils 7 and the lower coils 8 are controlled by the power supply system 2 to realize series power supply and independent power supply. The inner iron cores 6 of the upper and lower electromagnets 4, 5 are made of soft iron materials, the electromagnets generate magnetic fields when being electrified, and the magnetic forces disappear after being powered off. In addition, the specifications of the upper electromagnet 4 and the lower electromagnet 5 can be selected according to different geotechnical engineering test requirements and sample test scales. The upper electromagnet 4 can start the electric motor 15 through the numerical control operation system 3 to control the bearing 13 to rotate so as to adjust the height, and the height of the test operation table 9 is fully adapted to different heights under the condition of ensuring the uniformity and the strength of the magnetic field. The upper and lower magnetic shielding shells 10 and 11 are wrapped on the outer layers of the upper and lower electromagnets 4 and 5 to eliminate the interference of the environmental magnetic field on the internal magnetic field and the leakage of the internal magnetic field.

The test operation table 9 is positioned in a uniform magnetic field formed by the upper electromagnet 4 and the lower electromagnet 5, and the test operation table 9 is provided with a mode of mixing a soil sample with magnetic powder, so that a supergravity simulation effect based on electromagnetic field gradient magnetic force loading is obtained after the magnetic powder is saturated and magnetized.

The power supply system 2 converts alternating current into direct current by using the rectifier, so that the stability of power supply current and the stability of the magnetic field intensity of the upper electromagnet 4 and the lower electromagnet 5 in the test process are ensured.

The numerical control operation system 3 integrates digital display and computer operation functions, the computer controls the input current of the upper and lower electromagnets 4 and 5 according to the magnetic field measured by the gaussmeter 14, and stable target field intensity is obtained through real-time feedback as shown in fig. 4.

The operation method of the electromagnetic type geotechnical engineering hypergravity simulation device is as follows, as shown in figure 1: (1) preparing a soil sample in advance according to test requirements, adding a certain amount of magnetic powder (the magnetic powder adding ratio is determined by the test requirements and is not less than 20 percent, recommended) into the soil sample, uniformly stirring, and placing the prepared sample on a test operation table 9;

(2) and starting a power supply of the power supply system 2, controlling the bearing 13 to rotate through the numerical control operating system 3 to adjust the height of the upper electromagnet 4, and locking the height of the upper electromagnet 4 after the distance between the upper electromagnet 4 and the lower electromagnet 5 meets the test conditions.

(3) As shown in fig. 2, the upper and lower electromagnets 4 and 5 are powered in series, and the upper and lower coils 7 and 8 are powered in the same direction, thereby generating a uniform NS magnetic field strength in the area of the test station 9. The magnetic field intensity is measured by the gaussmeter 14 and fed back to the computer in the numerical control operation system 3, and the computer further controls the magnitude of the input current of the coils 7 and 8, as shown in fig. 4, a closed-loop feedback mechanism is formed, and finally the target field intensity is obtained. And under the condition of sufficiently long electrifying time, until the magnetic powder on the test operation table 9 reaches saturation magnetization.

(4) Referring to fig. 3, the independent power supply mode of the upper and lower electromagnets 4 and 5 is changed, and by controlling the magnitude of the power supply current, a field intensity mode can be formed in which the field intensity of the upper electromagnet 4 is strong and the field intensity of the lower electromagnet 5 is small (upper-large and lower-small modes), or in which the field intensity of the upper electromagnet 4 is small and the field intensity of the lower electromagnet 5 is strong (upper-small and lower-large modes), or in which the field intensities of the upper and lower electromagnets 4 and 5 are dynamically and linearly changed (dynamic mode). The direction of the magnetic field of the upper and lower electromagnets 4, 5 can also be changed by changing the direction of the current in the wire-wound coils 7 and 8 according to the experimental requirements. The gradient change of the field intensity can generate different magnetic field forces to the magnetic powder of the sample, so that different stress modes can be simulated, and the additional magnetic force is applied to the sample to achieve the Ng supergravity simulation effect.

(5) Test contents are developed on the test operation platform 9, a rock-soil body stability or rock-soil body-structure body interaction simulation test of the small-scale sample in the super-gravity environment is completed according to conventional operation, and a test result under the prototype size can be obtained according to a similar principle. Because the test platform is an open test operation platform, the test design can be adjusted by manual intervention in the test process.

(6) And after the test is finished, cleaning the test operating platform 9, and sequentially closing the power supplies of the numerical control operating system 3 and the power supply system 2 to keep the electromagnetic type high gravity field generator 1 clean.

The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features.