CN109799132B - Strain test-based method for identifying damage to foundation pile of high-pile wharf - Google Patents
Strain test-based method for identifying damage to foundation pile of high-pile wharf Download PDFInfo
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- CN109799132B CN109799132B CN201910040832.9A CN201910040832A CN109799132B CN 109799132 B CN109799132 B CN 109799132B CN 201910040832 A CN201910040832 A CN 201910040832A CN 109799132 B CN109799132 B CN 109799132B
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Abstract
The invention discloses a method for identifying damage of a foundation pile of a high-pile wharf based on strain test, which comprises the following steps: the method comprises the following steps: laying strain gauges and connecting a strain acquisition instrument; step two: applying a horizontal load and collecting a strain value; step three: analyzing the strain linear relation of each foundation pile; step four: comparing linear relations; step five: judging damaged foundation piles; step six: and determining the damage position of the foundation pile. The discrimination method adopted by the invention has the characteristics of convenient operation, reliable result, low cost and high efficiency.
Description
Technical Field
The invention relates to a method for identifying damage of a foundation pile of a high-pile wharf based on strain testing, and belongs to the technical field of identification of damage of the foundation pile of the high-pile wharf.
Background
The high-pile wharf is one of the main structural forms of port engineering buildings, has the characteristics of high bearing capacity, less material consumption, strong adaptability to dredging and ultra-deep, suitability for soft soil foundations and the like, and is easy to damage or destroy due to a plurality of components and complex structure. At present, a great number of high-pile wharfs in China are close to the service life, and the natural aging and corrosion of the wharf structure along with the increase of the service time and the fatigue of the structure under the overload effect for a long time all damage the structure to different degrees. The accumulation of these injuries can result in structural instability and failure of strength, which can result in catastrophic loss of life and property. In reality, the damage of the structure is not found in time, so that the events causing safety accidents due to damage accumulation are not enumerated. In order to reduce the disasters caused by engineering accidents, the research on the detection and identification of the damage of the code structure is very important.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for identifying the damage of the foundation pile of the high-pile wharf, which is convenient to operate, reliable in result, low in cost and high in efficiency.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for identifying damage to a foundation pile of a high-pile wharf based on a strain test comprises the following steps:
the method comprises the following steps: laying strain gauges, connecting a strain acquisition instrument, pasting the strain gauges at the same height position of the lower parts of pile caps of foundation piles at the same position of each bent frame of a wharf (the lower parts of pile caps without the pile caps and beam connecting nodes), wherein the strain acquisition direction is along the pile body direction, the pasting surface of the strain gauges is any surface (such as a round pile) of the pile body and the vertical surface of a cross beam, and the pasting position is the position of the tangent direction of the pile body and the vertical position of the cross beam, and connecting the strain gauges to the strain acquisition instrument;
step two: applying a horizontal load, collecting a strain value, applying the horizontal load on the upper part of the high-pile wharf, recording a strain time-course curve through a collecting instrument, and extracting the strain value of each strain gauge at the time of maximum load;
step three: analyzing the strain linear relation of each foundation pile, connecting coordinate points by taking the position of the bent foundation pile as an abscissa and the strain value at the maximum load as an ordinate to obtain the strain linear relation;
step four: comparing the linear relation, namely comparing the obtained strain linear relation with the linear relation when the wharf is intact;
step five: judging damaged foundation piles, and judging the damaged foundation piles according to linear relation analysis and judgment standards;
step six: and determining the damage position of the foundation pile, judging that a certain foundation pile is a damaged foundation pile, and then carrying out flaw detection on the damaged foundation pile through flaw detection equipment to determine the damage position of the foundation pile.
Further, in the second step, the ship is moored or hammered to apply horizontal load.
Further, the linear relationship when the wharf is intact in step four is obtained by: testing the determined intact code head segment; or by establishing a wharf numerical simulation model and using finite element calculation analysis to obtain the wharf numerical simulation model; or a perfect linear relationship measurement is performed after the wharf is built (or in a perfect state).
And further, in the fifth step, the judgment standard is that the strain value is reduced, and the damaged foundation pile is in a linear relation obviously deviating from the intact state on the curve.
Further, the flaw detection device in the sixth step comprises a radar or ultrasonic device.
Further, the method may also be used with a repeating frame structure similar to the high pile wharf structure.
The invention achieves the following beneficial effects:
1. the invention is based on that the high pile wharf structure is a repetitive bent combination, after a horizontal load is applied to the upper part of the high pile wharf structure, the strain connecting lines at the same positions on foundation piles at the same positions of all bent combinations have a certain linear relation, and the strain response of damaged foundation piles deviates, thereby providing a novel foundation pile damage judging method, and adopting a strain testing technology and a data post-processing technology to realize the damage judgment of the high pile wharf foundation piles quickly, wherein the strain testing technology and the data post-processing technology are simple and mature, and easy to operate;
2. the horizontal load loading equipment mode required by the invention can be selected according to the field, such as the load of ship berthing, impact and the like on the field is facilitated, and the invention is economical and easy to operate.
3. The invention is combined with the traditional flaw detection means such as radar, ultrasonic wave and the like, and the test result is accurate and reliable;
4. the invention can also be popularized and applied to the frame structure with the repetitive framework similar to the high-pile wharf foundation pile.
Drawings
FIG. 1 is a diagram of a high-piled wharf model;
FIG. 2 is a schematic diagram of numbering of foundation piles of the high-pile wharf model;
FIG. 3 is a horizontal impact load applying apparatus according to the embodiment;
FIG. 4 is a comparison graph of the linear relationship of the strains before and after the damage of the foundation pile in the example.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
In the embodiment, a high-pile wharf model is used for testing, as shown in fig. 1, a model original object diagram is shown, and fig. 2 is a foundation pile number corresponding to fig. 1, and the wharf damage identification is carried out by applying the method provided by the invention under two conditions, namely a working condition one and a working condition two.
The working condition I is as follows: when the upper part of the front row No. 2 pile is damaged by 20%, the left side is stressed;
working conditions are as follows: when the upper part of the front row No. 2 pile is damaged by 50%, the left side is stressed.
The specific test method is as follows:
the method comprises the following steps: and laying strain gauges and connecting a strain acquisition instrument. And (3) pasting a strain gauge 2cm below the pile cap of the outermost foundation pile (pile No. 1, pile No. 2, pile No. 3 and pile No. 4) of each bent frame of the wharf, and connecting the strain gauge to a strain acquisition instrument.
Step two: and applying a horizontal load and collecting a strain value. Applying horizontal impact load on the upper part of the bent frame, recording a strain time-course curve by a collecting instrument by adopting the device shown in figure 3, and extracting strain values of each strain gauge at the time of maximum load.
Step three: and analyzing the strain linear relation of each foundation pile. And connecting coordinate points by taking the position of the bent frame foundation pile as an abscissa and the strain value at the maximum load as an ordinate to obtain a strain linear relation.
Step four: and (5) comparing linear relations. The obtained linear relationship of strain was compared with the linear relationship when the wharf was intact, and the specific results are shown in fig. 4. The dock integrity linear relationship is measured by taking the integrity linear relationship when the dock model is in integrity.
Step five: and judging the damaged foundation pile. According to the linear relation analysis, the strain value of the No. 2 pile is reduced, the linear relation obviously deviates from the perfect linear relation on the curve, and the No. 2 pile damage is judged.
Step six: and determining the damage position of the foundation pile. After the No. 2 pile is judged to be damaged, flaw detection can be performed on the damaged foundation pile through flaw detection means such as radar and ultrasonic waves, and the damaged position of the foundation pile is determined.
And under the second working condition, repeating the steps.
The result is shown in fig. 4, under the working condition II, the strain value of the No. 2 pile is further reduced, the linear relation is more obviously deviated from the perfect linear relation on the curve, and the damage of the No. 2 pile can be judged.
The method for judging the damage of the No. 2 piles with different damage degrees is adopted, the result is visual, accurate and reliable, the operation method is simple and convenient, the operation is easy, and the method is suitable for popularization and application.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (5)
1. A method for identifying damage of a foundation pile of a high-pile wharf based on a strain test is characterized by comprising the following steps:
the method comprises the following steps: laying strain gauges, connecting the strain acquisition instrument, sticking the strain gauges at the lower parts of pile caps of foundation piles at the same position of each bent frame of the wharf and at the same height position of the lower part of a connection node of a beam without the pile caps, wherein the strain acquisition direction is along the pile body direction, the sticking surface of the strain gauge is any one surface of the pile body and the vertical surface of a cross beam, such as a round pile, the sticking position is the position of the tangent direction of the pile body and the vertical position of the cross beam, and connecting the strain gauges to the strain acquisition instrument;
step two: applying a horizontal load, collecting a strain value, applying the horizontal load on the upper part of the high-pile wharf, recording a strain time-course curve through a collecting instrument, and extracting the strain value of each strain gauge at the time of maximum load;
step three: analyzing the strain linear relation of each foundation pile, connecting coordinate points by taking the position of the bent foundation pile as an abscissa and the strain value at the maximum load as an ordinate to obtain the strain linear relation;
step four: comparing the linear relation, namely comparing the obtained strain linear relation with the linear relation when the wharf is intact;
step five: judging damaged foundation piles, judging the damaged foundation piles according to linear relation analysis and judgment standards, wherein the judgment standards are that the strain value is reduced, and the linear relation obviously deviates from the intact curve is that the damaged foundation piles occur;
step six: and determining the damage position of the foundation pile, judging that a certain foundation pile is a damaged foundation pile, and then carrying out flaw detection on the damaged foundation pile through flaw detection equipment to determine the damage position of the foundation pile.
2. The method for identifying the damage to the foundation pile of the high-pile wharf based on the strain test as claimed in claim 1, wherein in the second step, a horizontal load is applied by mooring or hammering of the ship.
3. The method for identifying the damage to the foundation pile of the high-pile wharf based on the strain test as claimed in claim 1, wherein the linear relation of the wharf in the fourth step when the wharf is intact is obtained by: testing the determined intact code head segment; or by establishing a wharf numerical simulation model and using finite element calculation analysis to obtain the wharf numerical simulation model; or after the wharf is built or in a good state, measuring the linear relation in the good state.
4. The method for identifying the damage to the foundation pile of the high-pile wharf based on the strain test as claimed in claim 1, wherein the flaw detection equipment in the sixth step comprises radar or ultrasonic equipment.
5. The method for identifying the damage to the foundation pile of the high-pile wharf based on the strain test as claimed in any one of claims 1 to 4, wherein the method is further applicable to a repetitive frame structure similar to the high-pile wharf structure.
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| CN112012254B (en) * | 2020-08-29 | 2021-08-03 | 东南大学 | Pile foundation comprehensive detection method based on unloading point method |
| CN117592253B (en) * | 2023-11-01 | 2024-05-10 | 上海交通大学 | Method for judging damage of high pile wharf of steel pipe pile |
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| KR101166139B1 (en) * | 2011-09-01 | 2012-07-18 | 한국전력공사 | Apparatus and method for horizontal load test of strip foundation |
| CN105369836A (en) * | 2014-08-22 | 2016-03-02 | 天津科鉴基础工程检测有限公司 | Novel pile foundation detection method |
| CN104360046B (en) * | 2014-11-06 | 2017-01-11 | 水利部交通运输部国家能源局南京水利科学研究院 | Comprehensive geophysical-prospecting combined diagnosis method for hidden danger inside wharf concrete structure |
| CN104614020B (en) * | 2015-01-30 | 2015-12-02 | 东南大学 | The original position whole detection method of long piled wharf horizontal bearing capacity and force model proterties |
| US20170160243A1 (en) * | 2015-12-02 | 2017-06-08 | Broadsens Corp. | Device and System for Structural Health Monitoring |
| CN106950129B (en) * | 2017-02-21 | 2019-09-10 | 中交上海三航科学研究院有限公司 | The dynamic detection method of high pile pier structure horizontal bearing capacity |
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