CN108240003B - Foundation pile detection method for existing building - Google Patents
Foundation pile detection method for existing building Download PDFInfo
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- CN108240003B CN108240003B CN201711420652.0A CN201711420652A CN108240003B CN 108240003 B CN108240003 B CN 108240003B CN 201711420652 A CN201711420652 A CN 201711420652A CN 108240003 B CN108240003 B CN 108240003B
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- 238000001514 detection method Methods 0.000 title claims abstract description 37
- 238000000034 method Methods 0.000 claims abstract description 34
- 238000005553 drilling Methods 0.000 claims abstract description 20
- 239000007822 coupling agent Substances 0.000 claims abstract description 12
- 238000005070 sampling Methods 0.000 claims abstract description 4
- 230000001133 acceleration Effects 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000004519 grease Substances 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 2
- 230000005284 excitation Effects 0.000 description 17
- 230000007547 defect Effects 0.000 description 8
- 230000008878 coupling Effects 0.000 description 5
- 238000010168 coupling process Methods 0.000 description 5
- 238000005859 coupling reaction Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 235000014121 butter Nutrition 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 230000001174 ascending effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000003313 weakening effect Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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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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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Piles And Underground Anchors (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
The invention relates to the field of building foundation pile detection, and discloses a foundation pile detection method for an existing building, which comprises the following steps: step one, vertically drilling and sampling from the top of a bearing platform (1) above a foundation pile (2), wherein a hole (3) obtained by drilling is deep below the pile top of the foundation pile (2); secondly, mounting a sensor (4) at the bottom of the hole (3), and filling the hole (3) with a coupling agent; step three, exciting the top of the bearing platform (1); and step four, collecting the detection signal of the sensor (4) and analyzing. The method can detect the foundation pile of the existing building with the pile top buried underground, and has accurate detection result and simple operation.
Description
Technical Field
The invention relates to the field of building foundation pile detection, in particular to a foundation pile detection method for an existing building.
Background
The foundation pile of the existing building is affected by geological disasters such as earthquake, debris flow and the like due to early construction, and the state of the pile body is not clear due to load change. In order to identify the safety and quality of an existing building, it is often necessary to perform a status check on its foundation piles.
In the prior art, a reflection wave method is generally adopted for detecting foundation piles of existing buildings, but the method has the following defects: (1) because the sensor needs to be arranged on the pile top, only the foundation pile with the pile top exposed on the ground or above the water surface can be detected, and the foundation pile buried underground of the existing buildings such as railways, roads and the like can not be detected; (2) the excitation point and the sensor for receiving signals are on the same plane, so that the front end of the actually measured reflection waveform is influenced by the upper structure, and the shallow defect of the foundation pile cannot be analyzed.
Disclosure of Invention
The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for detecting a foundation pile of an existing building, which can detect a foundation pile of an existing building having a pile top buried underground, and which has accurate detection results and simple operation.
In order to achieve the above object, the present invention provides a method for detecting a foundation pile of an existing building, the method comprising the steps of:
step one, vertically drilling a hole from the top of a bearing platform above a foundation pile and sampling, wherein the hole obtained by drilling is deep below the pile top of the foundation pile;
secondly, mounting a sensor at the bottom of the hole, and filling the hole with a coupling agent;
step three, exciting the top of the bearing platform;
and step four, collecting detection signals of the sensor and analyzing the detection signals.
Preferably, the depth of the hole in the foundation pile is 0.5-2m, and/or the hole has a diameter of 30-50 mm.
Preferably, the coupling agent is water or butter.
Preferably, the method comprises a step of smoothing the bottom of the hole before the step two.
Preferably, the second step includes mounting a weight on the sensor.
Preferably, the weight member is a weight magnetic block, and the second step includes installing a metal fitting at the bottom of the hole, so that the sensor is fixedly attached to the metal fitting through the weight magnetic block.
Preferably, the sensor is an acceleration sensor, and the fourth step includes connecting an output end of the sensor to an input end of a foundation pile detector, where the foundation pile detector is capable of receiving acceleration information detected by the sensor, and analyzing and processing the acceleration information to obtain state information of the foundation pile.
Preferably, the method comprises drilling with a micro-drill, and/or
The method comprises the step of exciting by adopting an exciting force rod.
Preferably, the method comprises the step of carrying out wave speed detection and analysis on the core sample obtained by drilling in the step one.
Preferably, the existing building is a single-pile and single-column structure.
Through the technical scheme, the method can be used for detecting the foundation pile of the existing building with the pile top buried underground, and is accurate in detection result and simple to operate. The bearing platform and the foundation pile are drilled, and the sensor is arranged at the bottom of the hole, so that the wave velocity of the foundation pile can be accurately measured; by filling the coupling agent into the hole, the excitation energy can effectively act on the foundation pile, and the reflected wave at the bottom of the pile can be prevented from weakening in the ascending process, so that the accuracy of the detection result is effectively ensured. In addition, the method can realize accurate detection of the foundation pile by only using one sensor.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic view of an embodiment of a foundation pile detection method of an existing building according to the present invention.
Description of the reference numerals
1 bearing platform and 2 foundation piles
3-hole 4 sensor
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
In the present invention, unless otherwise specified, the use of the terms of orientation such as "upper" and "lower" generally means the upper and lower directions as shown in the drawings. "inner and outer" refer to the inner and outer contours of the respective component itself.
The invention provides a method for detecting foundation piles of an existing building, which comprises the following steps:
step one, vertically drilling a hole from the top of a bearing platform 1 above a foundation pile 2 and sampling, wherein the hole 3 obtained by drilling is deep below the pile top of the foundation pile 2;
secondly, mounting a sensor 4 at the bottom of the hole 3, and filling the hole 3 with a coupling agent;
step three, exciting the top of the bearing platform 1;
and step four, collecting the detection signal of the sensor 4 and analyzing.
By the method, the foundation pile of the existing building with the underground pile top can be detected without excavating to expose the pile top out of the ground, and the method has the advantages of accurate detection result, simple operation and lower cost. Wherein, the actual wave velocity of the foundation pile 2 can be accurately detected by the sensor 4 by vertically drilling from the top of the bearing platform 1 to the position below the pile top of the foundation pile 2 and installing the sensor 4 at the bottom of the hole; by filling the hole 3 with the couplant, the couplant can play a role in coupling and transmitting vibration signals, so that the excitation energy can effectively act on the foundation pile 2, and the reflected wave at the bottom of the pile can be prevented from weakening in the ascending process, so that the accuracy of a detection result is effectively ensured. In addition, because the excitation applied to the top of the bearing platform 1 is vertical (namely the extension direction of the hole 3), and the excitation wave can be transmitted downwards, the sensor 4 is arranged at the bottom of the hole 3, the reflected wave speed in the vertical direction can be effectively measured, and the detection result (such as the pile length) of the foundation pile 2 can be more accurate; but also can avoid the sensor 4 from moving to influence the accuracy of the detection result. In addition, the sensor 4 is arranged at the bottom of the hole 3, so that the operation is very convenient, and the detection time can be greatly saved.
Moreover, compared with the prior art, the excitation point is arranged at the top of the bearing platform 1, and the sensor 4 is arranged in the foundation pile 2 below, so that a certain height difference exists between the excitation point and the signal receiving point (namely the position of the sensor 4), most transverse waves in the excitation waves can be filtered by the bearing platform 1, longitudinal waves can be effectively transmitted downwards, and the accuracy of the detection result of the sensor 4 is greatly improved.
In the present invention, the depth of the hole 3 in the foundation pile 2 is preferably 0.5 to 2m, for example, 0.5m, 0.7m or 1m, and it is preferable that the hole 3 is deep into the pile reinforcement of the foundation pile 2.
In the present invention, in order to enable the method to be applied to various existing building structures while avoiding damage to the cap and foundation pile, it is preferable to perform minimally invasive drilling of the cap 1 and foundation pile 2, and the hole 3 preferably has a hole diameter of 30-50 mm.
In the present invention, the position of the hole 3 in the horizontal direction of the platform 1 and the foundation pile 2 is not limited as long as it can vertically enter the foundation pile 2 from the top of the platform 1.
In the invention, the coupling agent can be water or butter. Of course, other materials capable of coupling and transmitting vibration signals may be used. According to a preferred embodiment of the invention, the coupling agent is water, and the water coupling can avoid the problems that the difficulty of coating butter in the closed micro space is high and the coating quality is not easy to control. It will be appreciated that the sensor 4 of the present invention is preferably waterproof due to the presence of the coupling agent.
In the present invention, in order to make the sensor 4 flatly and secretly placed at the bottom of the hole 3 to ensure that a real shaft signal can be detected, the method may include a step of polishing the bottom of the hole 3 before the second step. The influence of non-uniform construction waste at the bottom of the hole on the sensor 4 can be reduced by the bottom grinding treatment (which can be realized by drilling equipment).
In order to firmly fix the sensor 4 to the bottom of the hole 3 to prevent the sensor 4 from moving during the excitation process, thereby affecting the accuracy of the detection result, according to an embodiment of the present invention, the second step may include installing a weight on the sensor 4. This embodiment is particularly applicable in the case of water coupling inside the bore 3 (i.e. the coupling agent is water). Wherein, the weight member can adopt a non-magnetic weight member.
According to another embodiment of the present invention, when the inside of the port 3 is a metal coupling (for example, the coupling agent is grease), the weight member may be a weighted magnetic block, and the second step may include installing a metal fitting at the bottom of the port 3, so that the sensor 4 is fixedly attached to the metal fitting through the weighted magnetic block. Wherein the counterweight magnetic block can be installed at the bottom of the sensor 4, and the second step can further comprise coating grease on the upper surface of the metal fitting before the counterweight magnetic block is adsorbed on the metal fitting.
In the present invention, the sensor 4 is preferably an acceleration sensor, but is not limited thereto, and may be other types of sensors, such as a speed sensor. Step four may include connecting an output end of the sensor 4 to an input end of a foundation pile detector, where the foundation pile detector may receive acceleration information detected by the sensor 4, and analyze and process the acceleration information to obtain state information of the foundation pile 2.
In the above, the foundation pile detector may adopt a ZBL-P8100 foundation pile dynamometer, and the sensor 4 may adopt a LA5809B acceleration sensor. The state information of foundation pile 2 may include: concrete condition of pile top, real wave speed of pile body concrete, pile bottom position, pile length and different defects of pile body. The method for analyzing and processing the acceleration information to obtain the state information according to the present invention can be implemented by using an existing method, such as a low strain reflection method, and is not described in detail herein.
In the present invention, the drilling in the first step can be performed by using a micro-drilling machine, such as a HZ-20 micro-drilling machine. The excitation in the third step can be carried out by adopting an excitation force rod, such as a combined force rod HAM-04. It will be appreciated that the apparatus of the present invention for carrying out the drilling and exciting operations described above is not limited and may be any other apparatus that can be implemented. In the invention, the excitation can be segmented excitation, and excitation force rods with different frequencies can be selected for excitation according to different detection height requirements. For example, when it is desired to detect a defect condition of foundation pile 2 within, for example, 3m down from the pile top, a low frequency exciting force bar may be used, and when it is desired to detect a defect condition of foundation pile 2 within a longer range, a high frequency exciting force bar may be used.
In the invention, the core sample obtained by drilling in the first step can be subjected to wave velocity detection and analysis. By respectively testing the wave velocity of core samples with different depths, the concrete condition of the bearing platform 1, the shallow defect information of the foundation pile and the quality information of the joint of the foundation pile 2 and the bearing platform 1 can be obtained. By the method, the problem that in the prior art, the shallow defect of the foundation pile cannot be analyzed due to the fact that the front end of the actually measured reflection waveform is affected by the upper structure because the excitation point and the sensor are on the same plane can be effectively solved.
The superstructure described above may be a pier located above the platform 1. By adopting the method of the invention, in the actual detection and analysis process, in order to avoid the interference of the bridge pier on the detection result of the foundation pile 2, the signal of the corresponding bridge pier position can be identified in advance according to the section change of the bridge pier, the defect analysis is not needed after the bridge pier signal is identified in the test pattern displayed by the foundation pile detector, and the signal can also be directly eliminated by carrying out band-pass filtering on the frequency corresponding to the pier height position.
The detection method is suitable for foundation piles of existing buildings with any pile tops buried underground, and particularly for the existing buildings with single-pile and single-column structures.
In addition, in the invention, the method can further comprise the step of cleaning the top of the bearing platform 1 before the step one, and removing dust and impurities, so as to avoid interfering with vibration excitation operation and influencing wave velocity detection.
The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (7)
1. A method for detecting a foundation pile of an existing building, comprising the steps of:
the method comprises the following steps of firstly, vertically drilling a hole from the top of a bearing platform (1) above a foundation pile (2) and sampling, wherein the hole (3) obtained by drilling is deep below the pile top of the foundation pile (2), the number of the holes (3) is one, and the bottom of the hole (3) is subjected to grinding treatment;
secondly, mounting a sensor (4) at the bottom of the hole (3), mounting a weight on the sensor (4), and filling the hole (3) with a coupling agent;
step three, exciting the top of the bearing platform (1);
step four, collecting the detection signal of the sensor (4) and analyzing,
the method also comprises the step of carrying out wave speed detection and analysis on the core sample obtained by drilling in the step one.
2. Foundation pile detection method of an existing building according to claim 1, characterized in that the depth of the hole (3) in the foundation pile (2) is 0.5-2m and/or the hole (3) has a diameter of 30-50 mm.
3. The foundation pile detection method for an existing building according to claim 1, wherein the coupling agent is water or grease.
4. The foundation pile detection method of the existing building according to claim 1, wherein the weight member is a weighted magnetic block, and the second step comprises installing a metal fitting at the bottom of the hole (3) and fixedly attaching the sensor (4) to the metal fitting through the weighted magnetic block.
5. Method for pile detection in an existing building according to claim 1, characterized in that the sensor (4) is an acceleration sensor, and in that the fourth step comprises connecting the output of the sensor (4) to the input of a pile detector capable of receiving the acceleration information detected by the sensor (4) and of analyzing and processing it to obtain status information of the pile (2).
6. The foundation pile detection method for an existing building according to claim 1,
the method comprises drilling with a micro-drill, and/or
The method comprises the step of exciting by adopting an exciting force rod.
7. The method for inspecting foundation piles of an existing building according to any one of claims 1 to 6, wherein the existing building is a single-pile single-column structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711420652.0A CN108240003B (en) | 2017-12-25 | 2017-12-25 | Foundation pile detection method for existing building |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711420652.0A CN108240003B (en) | 2017-12-25 | 2017-12-25 | Foundation pile detection method for existing building |
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| Publication Number | Publication Date |
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| CN108240003A CN108240003A (en) | 2018-07-03 |
| CN108240003B true CN108240003B (en) | 2020-08-18 |
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| CN201711420652.0A Active CN108240003B (en) | 2017-12-25 | 2017-12-25 | Foundation pile detection method for existing building |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111042215A (en) * | 2018-10-15 | 2020-04-21 | 广州市市政工程试验检测有限公司 | Existing building foundation pile quality detection method and device |
| CN111042216B (en) * | 2018-10-15 | 2021-12-28 | 广州市市政工程试验检测有限公司 | Comprehensive detection method for integrity and bearing characteristics of existing building foundation pile |
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| JP4667228B2 (en) * | 2005-12-21 | 2011-04-06 | 株式会社竹中工務店 | Pile inspection method and sensor crimping device |
| CN105887940A (en) * | 2014-11-13 | 2016-08-24 | 中国建筑科学研究院 | Double-speed low-strain method for detecting integrity of existing pile foundation by adopting excitation in pile body |
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