CN112832301B - Electromagnetic cast-in-place pile and precast pile detection method based on cylindrical coordinate system - Google Patents
Electromagnetic cast-in-place pile and precast pile detection method based on cylindrical coordinate system Download PDFInfo
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- CN112832301B CN112832301B CN202011619592.7A CN202011619592A CN112832301B CN 112832301 B CN112832301 B CN 112832301B CN 202011619592 A CN202011619592 A CN 202011619592A CN 112832301 B CN112832301 B CN 112832301B
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
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Abstract
The invention discloses an electromagnetic filling pile and precast pile detection method based on a cylindrical coordinate system, which comprises the steps of manufacturing a pile foundation, detecting the arrangement of a conductor structure, detecting by utilizing the propagation characteristic of electromagnetic waves, calculating the distribution rule of the electromagnetic waves in a pile body, judging the integrity of concrete in the pile body, solving and calculating by using a Maxwell equation under the cylindrical coordinate system to obtain the intensity of electromagnetic signals, and performing inversion imaging by using an electromagnetic wave imaging technology; the invention uses the regular phenomena of energy reduction, diffraction, refraction, reflection and the like generated in the electromagnetic wave propagation process as the theoretical detection pile foundation, can greatly improve the detection precision and the detection efficiency, and makes the evaluation of the pile foundation approximate to the reality by analyzing and calculating the mathematical tool for solving the Maxwell equation set based on the cylindrical coordinate system, and has the advantages of simple operation, high reliability of the detection result and easy popularization.
Description
Technical Field
The invention relates to the technical field of concrete pile detection, in particular to an electromagnetic cast-in-place pile and precast pile detection method based on a cylindrical coordinate system.
Background
Pile foundations, an important foundation form for engineering construction, are widely used in building construction and road and bridge construction. The method is usually underground or underwater, has the characteristics of complex procedures, high technical requirements, high construction difficulty and the like, and is easy to cause quality problems. Therefore, to accurately judge the performance of the foundation pile, the technology of engineering pile detection must be improved.
In construction, due to geological conditions, construction conditions, the technical level of constructors and the like, quality problems such as necking, pile breaking, local mud clamping of a pile body, concrete segregation of the pile body, loose concrete at the top of the pile and the like are easy to occur. Therefore, the important significance is achieved in researching how to effectively detect the quality of the pile foundation. Common detection methods include a drilling coring method, a sound wave transmission method, a low strain reflection wave method, a high strain method, a static load test and a self-balancing method;
the existing detection method has a detection blind area, the defect size cannot be judged quantitatively, the cost is high by using the embedded sounding pipe, the transient excitation of the pile head is greatly interfered by the outside of a site, the reflected signal of the defect at the rear section of the pile body is difficult to detect, and the position of the fiber cannot be ensured by adopting the embedded fiber method because the fiber has no mechanical property, so that the invention provides the electromagnetic cast-in-place pile and precast pile detection method based on a cylindrical coordinate system to solve the problems in the prior art.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method for detecting an electromagnetic bored concrete pile or a precast pile based on a cylindrical coordinate system, which uses regular phenomena such as energy reduction, diffraction, refraction, and reflection generated in an electromagnetic wave propagation process as a theoretical detection pile foundation, and can greatly improve detection accuracy and detection efficiency.
In order to realize the purpose of the invention, the invention is realized by the following technical scheme: a method for detecting an electromagnetic cast-in-place pile and a precast pile based on a cylindrical coordinate system comprises the following steps:
step one, arranging a longitudinal steel bar at the center of a cylindrical pile body during pile body forming, taking the longitudinal steel bar as an inner conductor of a transmitting end, then taking a steel bar cage of the pile body as an outer conductor of a receiving end, and filling concrete between the inner conductor of the transmitting end and the outer conductor of the receiving end, wherein the concrete is used as an electromagnetic wave transmission conductor medium due to the electromagnetic property of the concrete;
connecting a power supply to the inner conductor of the transmitting end, taking a longitudinal bar parallel to the longitudinal bar of the inner conductor of the transmitting end at the periphery of the reinforcement cage as a good receiving conductor, taking a transverse stirrup of the reinforcement cage as a good peripheral conductor, and arranging a receiver at the periphery of the pile body;
turning on a line power supply, transmitting an electric signal by using the inner conductor of the transmitting end, and exciting a magnetic signal to be transmitted in the medium of the electromagnetic transmission conductor by the electric signal to reach the outer conductor of the peripheral receiving end to be received by a receiver;
solving the Maxwell equation set under the cylindrical coordinate system according to the set parameters to obtain the distribution rule of the electromagnetic waves in the pile body;
and fifthly, imaging is carried out by utilizing the received electromagnetic signals, simulation research is carried out by utilizing a finite difference calculation method, and the integrity of the concrete in the pile body is judged by utilizing an inversion method and electromagnetic wave characteristics.
The further improvement lies in that: and the line power supply and the receiver in the second step are electrically connected with a control server, a microprocessor, a detector, a signal analyzer and a switch circuit, and the line power supply in the second step is connected with an inner conductor of the transmitting end of the longitudinal steel bar so as to enable the inner conductor to transmit linear source electromagnetic waves.
The further improvement lies in that: in the third step, the linear source electromagnetic wave transmitted by the inner conductor of the transmitting end is transmitted to the receivers by the outer conductor of the receiving end, and each receiver receives signals of the linear source electromagnetic waves with different heights.
The further improvement is that: in the fourth step, as the pile body is a cylinder, the propagation of the linear source electromagnetic wave signal in the cylinder follows the Maxwell equation principle in the cylindrical coordinate system, and a Maxwell equation set in the cylindrical coordinate system is obtained.
The further improvement lies in that: the parameters in the fourth step comprise the dielectric constant of the concrete material, the dielectric constant of the steel bar and the diameter of the pile body.
The further improvement lies in that: and in the fifth step, inversion imaging is carried out by utilizing the principle of electromagnetic parameter imaging by utilizing electromagnetic signal imaging, the inversion method in the fifth step is a least square method, and resistivity and waveforms are subjected to inversion imaging by utilizing the least square method.
The further improvement lies in that: the electromagnetic wave characteristic in the fifth step refers to that the electromagnetic wave is transmitted in the medium and has strong electromagnetic energy attenuation, and the electromagnetic wave can generate reflection on an interface of medium wave impedance, so that the medium distribution with the impedance changed is distinguished.
The invention has the beneficial effects that: the invention uses the regular phenomena of energy reduction, diffraction, refraction, reflection and the like generated in the electromagnetic wave propagation process as the theoretical detection pile foundation, can greatly improve the detection precision and the detection efficiency, and makes the evaluation of the pile foundation approximate to the reality by analyzing and calculating the mathematical tool for solving the Maxwell equation set based on the cylindrical coordinate system, and has the advantages of simple operation, high reliability of the detection result and easy popularization.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a flow chart of the operation of the present invention.
FIG. 2 is a top view of the detection structure arrangement of the present invention.
FIG. 3 is a top view of a main view of the layout of the detection structure of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," "fourth," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
As shown in fig. 1, 2 and 3, the present embodiment provides a method for detecting an electromagnetic cast-in-place pile and a precast pile based on a cylindrical coordinate system, including the following steps:
step one, arranging a longitudinal steel bar at the center of a cylindrical pile body during pile body forming, taking the longitudinal steel bar as an inner conductor of a transmitting end, then taking a steel bar cage of the pile body as an outer conductor of a receiving end, and filling concrete between the inner conductor of the transmitting end and the outer conductor of the receiving end, wherein the concrete is used as an electromagnetic wave transmission conductor medium due to the electromagnetic property of the concrete;
connecting a power supply to the inner conductor of the transmitting end, taking a longitudinal bar parallel to the longitudinal bar of the inner conductor of the transmitting end at the periphery of the reinforcement cage as a good receiving conductor, taking a transverse stirrup of the reinforcement cage as a good peripheral conductor, and arranging a receiver at the periphery of the pile body;
turning on a line power supply, transmitting an electric signal by using the inner conductor of the transmitting end, and exciting a magnetic signal to be transmitted in the medium of the electromagnetic transmission conductor by the electric signal to reach the outer conductor of the peripheral receiving end to be received by a receiver;
solving the Maxwell equation set under the cylindrical coordinate system according to the set parameters to obtain the distribution rule of the electromagnetic waves in the pile body;
and fifthly, imaging is carried out by utilizing the received electromagnetic signals, simulation research is carried out by utilizing a finite difference calculation method, and the integrity of the concrete in the pile body is judged by utilizing an inversion method and electromagnetic wave characteristics.
And the line power supply and the receiver in the second step are electrically connected with a control server, a microprocessor, a detector, a signal analyzer and a switch circuit, and the line power supply in the second step is connected with an inner conductor of the transmitting end of the longitudinal steel bar so as to enable the inner conductor to transmit linear source electromagnetic waves.
In the third step, the linear source electromagnetic wave transmitted by the inner conductor of the transmitting end is transmitted to the receivers by the outer conductor of the receiving end, and each receiver receives signals of the linear source electromagnetic waves with different heights.
In the fourth step, as the pile body is a cylinder, the propagation of the linear source electromagnetic wave signal in the cylinder follows the Maxwell equation principle in the cylindrical coordinate system, and a Maxwell equation set in the cylindrical coordinate system is obtained.
The parameters in the fourth step comprise the dielectric constant of the concrete material, the dielectric constant of the steel bar and the diameter of the pile body.
And in the fifth step, inversion imaging is carried out by utilizing the principle of electromagnetic parameter imaging by utilizing electromagnetic signal imaging, the inversion method in the fifth step is a least square method, and resistivity and waveforms are subjected to inversion imaging by utilizing the least square method.
The electromagnetic wave characteristic in the fifth step refers to that the electromagnetic wave is transmitted in the medium and has strong electromagnetic energy attenuation, and the electromagnetic wave can generate reflection on an interface of medium wave impedance, so that the medium distribution with the impedance changed is distinguished.
During detection, the steel bars in the center of the pile body are used for supplying power, linear source electromagnetic waves are emitted, the electromagnetic waves are attenuated, reflected, refracted and diffracted at an impedance interface through concrete (if the pile body is complete, the electromagnetic waves such as cracks, cavities and the like do not change), a steel reinforcement cage around the pile body is used as a receiving conductor, receivers and detectors are arranged at different positions on the periphery of the pile body to receive the transmitted electromagnetic signals, inversion calculation is carried out according to the energy and the waveform of the electromagnetic signals, and electromagnetic wave mapping is achieved so that the quality of the pile body can be evaluated.
According to the electromagnetic filling pile and precast pile detection method based on the cylindrical coordinate system, the pile foundation is theoretically detected by utilizing the regular phenomena of energy reduction, diffraction, refraction, reflection and the like generated in the electromagnetic wave propagation process, the detection precision and the detection efficiency can be greatly improved, and the mathematical tool for solving the Maxwell equation set based on the cylindrical coordinate system is used for analyzing and calculating, so that the evaluation of the pile foundation approaches to the reality, the operation is simple, the reliability of the detection result is high, and the popularization is easy.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (6)
1. A method for detecting an electromagnetic cast-in-place pile and a precast pile based on a cylindrical coordinate system is characterized by comprising the following steps:
step one, arranging a longitudinal steel bar at the center of a cylindrical pile body during pile body forming, taking the longitudinal steel bar as an inner conductor of a transmitting end, then taking a steel bar cage of the pile body as an outer conductor of a receiving end, and filling concrete between the inner conductor of the transmitting end and the outer conductor of the receiving end, wherein the concrete is used as an electromagnetic wave transmission conductor medium due to the electromagnetic property of the concrete;
connecting a power supply to the inner conductor of the transmitting end, taking a longitudinal bar parallel to the longitudinal bar of the inner conductor of the transmitting end at the periphery of the reinforcement cage as a good receiving conductor, taking a transverse stirrup of the reinforcement cage as a good peripheral conductor, and arranging a receiver at the periphery of the pile body;
turning on a line power supply, transmitting an electric signal by using the inner conductor of the transmitting end, and exciting a magnetic signal to be transmitted in the medium of the electromagnetic transmission conductor by the electric signal to reach the outer conductor of the peripheral receiving end to be received by a receiver;
solving the Maxwell equation set under the cylindrical coordinate system according to the set parameters to obtain the distribution rule of the electromagnetic waves in the pile body;
imaging by using the received electromagnetic signals, performing simulation research by using a finite difference calculation method, and judging the integrity of concrete in the pile body by using an inversion method and electromagnetic wave characteristics;
the electromagnetic wave characteristic in the fifth step refers to that the electromagnetic wave is transmitted in the medium and has strong electromagnetic energy attenuation, and the electromagnetic wave can generate reflection on an interface of medium wave impedance, so that the medium distribution with the impedance changed is distinguished.
2. The electromagnetic cast-in-place pile and precast pile detection method based on the cylindrical coordinate system as claimed in claim 1, wherein: and the line power supply and the receiver in the second step are electrically connected with a control server, a microprocessor, a detector, a signal analyzer and a switch circuit, and the line power supply in the second step is connected with an inner conductor of the transmitting end of the longitudinal steel bar so as to enable the inner conductor to transmit linear source electromagnetic waves.
3. The electromagnetic cast-in-place pile and precast pile detection method based on the cylindrical coordinate system as claimed in claim 1, wherein: in the third step, the linear source electromagnetic wave transmitted by the inner conductor of the transmitting end is transmitted to the receivers by the outer conductor of the receiving end, and each receiver receives signals of the linear source electromagnetic waves with different heights.
4. The electromagnetic cast-in-place pile and precast pile detection method based on the cylindrical coordinate system as claimed in claim 1, wherein: in the fourth step, as the pile body is a cylinder, the propagation of the linear source electromagnetic wave signal in the cylinder follows the Maxwell equation principle in the cylindrical coordinate system, and a Maxwell equation set in the cylindrical coordinate system is obtained.
5. The electromagnetic cast-in-place pile and precast pile detection method based on the cylindrical coordinate system as claimed in claim 1, wherein: the parameters in the fourth step comprise the dielectric constant of the concrete material, the dielectric constant of the steel bar and the diameter of the pile body.
6. The electromagnetic cast-in-place pile and precast pile detection method based on the cylindrical coordinate system as claimed in claim 1, wherein: and in the fifth step, inversion imaging is carried out by utilizing the principle of electromagnetic parameter imaging by utilizing electromagnetic signal imaging, the inversion method in the fifth step is a least square method, and resistivity and waveforms are subjected to inversion imaging by utilizing the least square method.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103669426A (en) * | 2012-09-13 | 2014-03-26 | 广东省地质物探工程勘察院 | Borehole transient electromagnetic detection method for cast-in-place pile reinforcement cage length |
| CN103898931A (en) * | 2014-04-11 | 2014-07-02 | 广州建设工程质量安全检测中心有限公司 | Three-dimensional foundation pile detection device and method based on borehole radar |
| KR101897905B1 (en) * | 2017-03-22 | 2018-09-12 | 고려대학교 산학협력단 | Pile integrity testing apparatus for using electromagnetic waves |
| CN108978740A (en) * | 2018-08-28 | 2018-12-11 | 大连理工大学 | Drilled pile quality determining method based on distributed ultrasound wave sensor |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103669426A (en) * | 2012-09-13 | 2014-03-26 | 广东省地质物探工程勘察院 | Borehole transient electromagnetic detection method for cast-in-place pile reinforcement cage length |
| CN103898931A (en) * | 2014-04-11 | 2014-07-02 | 广州建设工程质量安全检测中心有限公司 | Three-dimensional foundation pile detection device and method based on borehole radar |
| KR101897905B1 (en) * | 2017-03-22 | 2018-09-12 | 고려대학교 산학협력단 | Pile integrity testing apparatus for using electromagnetic waves |
| CN108978740A (en) * | 2018-08-28 | 2018-12-11 | 大连理工大学 | Drilled pile quality determining method based on distributed ultrasound wave sensor |
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