CN112211236A - Engineering pile body defect detection method - Google Patents
Engineering pile body defect detection method Download PDFInfo
- Publication number
- CN112211236A CN112211236A CN202011274489.3A CN202011274489A CN112211236A CN 112211236 A CN112211236 A CN 112211236A CN 202011274489 A CN202011274489 A CN 202011274489A CN 112211236 A CN112211236 A CN 112211236A
- Authority
- CN
- China
- Prior art keywords
- pile body
- excitation
- depth
- neck
- defects
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D33/00—Testing foundations or foundation structures
Abstract
A method for detecting defects of an engineering pile body comprises the following steps: (1) detecting by a detector in the detection hole, and drawing a time-depth oscillogram; (2) determining whether pile body defects exist according to the time-depth oscillogram; (3) for the pile body with the defects of neck expansion and neck reduction, the other side of the pile body is provided with an excitation hole; (4) determining the transmission speed of the shock wave on the pile body; (5) and (4) detecting an excitation wave signal of the excitation hole and the transmission speed of the excitation wave in the pile body determined in the step (4) through a detector, and determining the neck-expanding length of the neck-expanding defects or the neck-contracting length of the neck-contracting defects.
Description
Technical Field
The invention relates to the technical field of pile foundation detection, in particular to an excitation detection method for pile body defect in building engineering monitoring.
Background
The pile foundation is used for bearing and transferring the upper load of a structure, and the most common concrete pile is used at present. The concrete pile is divided into a prefabricated pile and a cast-in-place pile, the grade of the concrete pile is controlled by design indexes, and the concrete pile has clear requirements on the concrete strength and the composition of the pile body. At present, the pile foundation is widely applied to various building projects, and the pile foundation is required to be applied to improve the stability of a building structure no matter the building structure is a civil engineering structure, a marine engineering structure and a bridge structure, or a special building structure. The quality of the pile foundation directly determines the overall quality of the project, so that the scientific detection of the quality of the pile foundation is very important. The pile foundation detection is that according to the characteristics of concrete pile foundation, select reasonable pile foundation detection method for use, detect the key index that length, integrality, stability, bearing capacity etc. of stake need find out, judge whether its each item index has reached the design requirement.
The nondestructive testing technique is to directly test on the structure or drill a core sample in the structure to test the internal quality of the structure and estimate the strength and quality defects of the structure without damaging the structural members, and is suitable for quality monitoring in the engineering construction process, as well as for quality verification during the completion of the engineering and during the use of the building. Nondestructive testing has the advantages of rapidness, simplicity, convenience, intuition, no damage and the like, and is increasingly widely applied and developed in construction projects. The foundation pile nondestructive testing technology is a new field of engineering geophysical prospecting development, and is an important means for concealed engineering construction quality inspection and a main basis for construction engineering supervision quality evaluation.
The main working process of the low strain reflection wave method is through knocking the pile top, thereby producing stress waves, then the stress waves of production propagate downwards, again along the in-process of pile body propagation, if pile foundation appears similar to the flaring in itself, when separating defects such as disconnected pile, the sectional impedance of its pile foundation itself will change, stress waves will divide into two parts like this, one of them part becomes reflection wave upward propagation, another part becomes transmission wave and passes defect interface downward propagation until reaching the pile foundation bottom then reflects, the detection personnel just can judge the quality of pile foundation itself and calculate the length of pile foundation through the curve characteristic of accepting like this.
The high strain method is that a vertical transient impact load is applied to the pile top by a hammering system, the force acting on the pile top is close to the actual stress level of the pile, so that the pile body generates obvious acceleration and inertia force, the pile body strain is equivalent to the engineering pile strain level, the impact force generates relative displacement between pile soils, thereby the side friction resistance of the pile is fully exerted, the end resistance is correspondingly excited, force and acceleration sensors are symmetrically arranged at a certain distance from the pile top at two sides of the pile, a hammering response signal is received by a foundation pile dynamic measuring instrument, so that the bearing capacity of a single pile and the structural integrity of the pile body are calculated and analyzed,
the working principle of the ultrasonic detection technology is that according to the fluctuation theory, acoustic pipes are embedded in a pile body to be detected, high-frequency elastic pulse waves are transmitted in one pipe through an ultrasonic pulse emission source, transmitted ultrasonic waves are received in the other pipe at a corresponding height, a high-precision receiving system is used for recording, and quality defects in concrete can be judged. The prior art ultrasonic pile foundation detection methods are as CN105297786A and CN 110656665A. The ultrasonic detection method has the defects that (1) the implementation of the ultrasonic method needs to embed the sounding pipe in advance during the construction of the pile foundation, so that a detection object is limited, and the detection cost is increased; (2) because the sounding pipe is arranged in the pile body, the difficulty exists in judging the defect types of the pile foundation, such as necking, necking and the like.
The side-hole transmission wave method is a new method developed on the basis of the reflection wave method. The method is characterized in that a hammer is used for vertically knocking on the top surface of a pile to generate compression waves, the compression waves are transmitted downwards along the pile body and meet surrounding soil layers, a sensor is placed in a hole drilled beside the pile in advance to receive transmission wave signals, and therefore wave waves of different depths are read and a first arrival time-depth relation graph is drawn. And determining the depth position of the pile foundation defect according to the position of the inflection point of the time-depth relation graph. The prior art CN105672371A, CN108547332A and CN108560617A disclose a technique for detecting defects of pile foundations by a side-hole transmitted wave method. The side hole transmission wave method can determine the defect types of necking, necking and the like in the pile foundation, but cannot determine the specific necking and necking size of necking and necking in the pile foundation.
Disclosure of Invention
The invention provides a side hole transmission excitation detection method for pile body defects, which can determine defect types in the pile body defects and can also determine specific sizes of necking and necking defects.
In order to solve one aspect of the above problems, the present invention provides a method for detecting a defect of an engineering pile body, including: (1) detecting by a detector in the detection hole, and drawing a time-depth oscillogram; (2) determining whether pile body defects exist according to the time-depth oscillogram; (3) for the pile body with the defects of neck expansion and neck reduction, the other side of the pile body is provided with an excitation hole; (4) determining the transmission speed of the shock wave on the pile body; (5) and (4) detecting an excitation wave signal of the excitation hole and the transmission speed of the excitation wave in the pile body determined in the step (4) through a detector, and determining the neck-expanding length of the neck-expanding defects or the neck-contracting length of the neck-contracting defects.
In the step (1), the excitation waves excited at the top of the pile or at the side surface of the top of the pile are detected at different depths of the detection hole through a detector, and a time-depth waveform diagram is drawn according to the detection signals.
And (3) in the step (2), when part of region points in the time-depth oscillogram are located in the left region of the head wave travel time connecting line of the rest points, determining that the pile body has the defects of neck expansion.
And (3) in the step (2), when part of region points in the time-depth oscillogram are located in the right region of the head wave travel time connecting line of the rest points, determining that the pile body has the defects of neck expansion.
In the step (3), the axis of the excitation hole, the axis of the pile body and the axis of the detection hole are located on the same plane.
In the step (3), for the neck-expanding defects, determining the defect depth D =sigmaDi/n, wherein Di is the depth of each point of the left area point of the head-wave travel time connecting line of the rest points, and n is the number of the left area points of the head-wave travel time connecting line of the rest points; and for the necking defects, determining the defect depth D =sigmaDi/n, wherein Di is the depth of each point of the right area point of the head wave travel time connecting line of the rest points, and n is the number of the right area points of the head wave travel time connecting lines of the rest points.
And (4) in the step (3), setting the depth of the excitation hole to be 2-3 m longer than the lower limit of the depth of the defect.
In the step (4), an excitation wave is generated on the side face of the pile body through an excitation source, the arrival time t of the head wave is detected on the side face corresponding to the pile body, and the transmission speed V1= L/t of the excitation wave on the pile body is determined according to the diameter L of the pile body.
In the step (5), the length of the neck-expanding is determined according to the following modes: arranging an excitation source at the defect-free depth of a pile body in an excitation hole, and arranging a detector at the same depth of the excitation source to detect the first wave time t 1; arranging an excitation source at the depth D of the pile body defect in the excitation hole, and arranging a detector in the detection hole at the same depth of the excitation source to detect the first wave time t 2; and calculating the length h of the expanded neck (t 2-t 1) (V1V 2)/(V2-V1), wherein V1 is the transmission speed of the excitation wave on the pile body, V2 is the transmission speed of the excitation wave on the soil layer around the pile body, and V2= (S-L)/(t 1-L/V1), wherein S is the axial distance between the detection hole and the excitation hole, and L is the diameter of the pile body.
In the step (5), the neck length is determined according to the following manner: arranging an excitation source at the defect-free depth of a pile body in an excitation hole, and arranging a detector at the same depth of the excitation source to detect the first wave time t 1; arranging an excitation source at the depth D of the pile body defect in the excitation hole, and arranging a detector in the detection hole at the same depth of the excitation source to detect the first wave time t 2; and calculating the necking length h = (t 2-t 1) (V1V 2)/(V1-V2), wherein V1 is the transmission speed of the excitation wave on the pile body, V2 is the transmission speed of the excitation wave on the soil layer around the pile body, and V2= (S-L)/(t 1-L/V1), wherein S is the axial distance between the detection hole and the excitation hole, and L is the diameter of the pile body.
Drawings
Fig. 1 is a diagram illustrating steps of a pile foundation defect excitation detection method according to an embodiment of the present invention.
Detailed Description
The invention will be further described in detail with reference to the drawings and the detailed description, which are provided for the purpose of clearly understanding the invention and are not intended to limit the invention.
As shown in fig. 1, a method for detecting a defect of an engineering pile body according to an embodiment of the present invention includes the following steps:
(1) by detecting the wave of the detector in the detection hole, a time-depth oscillogram is drawn
The drilling of pile foundation side soil layer sets up the inspection hole, and the inspection hole degree of depth can set up to 2~3m than the pile foundation degree of depth length, sets up the detection pipe in the inspection hole. The detector can extend into different depths of the detection conduit through the hanging rope; exciting an excitation wave at the top of the pile or on the side surface of the top of the pile through an excitation source, extending a detector into positions with different depths in the detection guide pipe, and detecting the excitation wave emitted by the excitation source; the time-depth waveform is plotted against the signal from the detector.
(2) Determining whether pile body defects exist according to time-depth oscillograms
The head wave travel time connecting line of the time-depth oscillogram is a straight line, and the fact that the pile body is not defective is shown. Two straight lines with different slopes exist in a head wave travel time connecting line of the time-depth oscillogram, and the pile breaking defect is found at the corner of the slope. And when a part of region points in the time-depth waveform diagram are positioned in the left region of the head wave travel time connecting line of the other points, determining that the pile body has the defects of neck expansion. And when part of region points in the time-depth waveform diagram are positioned in the right region of the head wave travel time connecting line of the other points, determining that the pile body has the defects of neck expansion.
(3) For the pile body with the defects of neck expansion and neck reduction, the other side of the pile body is provided with an excitation hole
For the neck-expanding defects, determining the defect depth D =sigmaDi/n, wherein Di is the depth of each point of a left area point of the head wave travel time connecting line of the rest points, and n is the number of the left area points of the head wave travel time connecting line of the rest points; and for the necking defects, determining the defect depth D =sigmaDi/n, wherein Di is the depth of each point of the right area point of the head wave travel time connecting line of the rest points, and n is the number of the right area points of the head wave travel time connecting lines of the rest points. And the other side of the pile body is provided with an excitation hole at the position symmetrical to the detection hole, and the axis of the excitation hole, the axis of the pile body and the axis of the detection hole are positioned on the same plane. The depth of the excitation hole is 2-3 m longer than the lower limit of the depth of the neck-expanding defect or the neck-reducing defect.
(4) Determining the transmission speed of the shock wave in the pile body
The method comprises the steps of generating an excitation wave on the side face of a pile body through an excitation source, detecting the arrival time t of a head wave on the side face corresponding to the pile body, and determining the transmission speed V1= L/t of the excitation wave on the pile body according to the diameter L of the pile body.
(5) And determining the neck-expanding length of the neck-expanding type defect or the neck-reducing length of the neck-reducing type defect.
For a neck-out type defect, the neck-out length is determined as follows: arranging an excitation source at the defect-free depth of a pile body in an excitation hole, and arranging a detector at the same depth of the excitation source to detect the first wave time t 1; arranging an excitation source at the depth D of the pile body defect in the excitation hole, and arranging a detector in the detection hole at the same depth of the excitation source to detect the first wave time t 2; and calculating the length h of the expanded neck (t 2-t 1) (V1V 2)/(V2-V1), wherein V1 is the transmission speed of the excitation wave on the pile body, V2 is the transmission speed of the excitation wave on the soil layer around the pile body, and V2= (S-L)/(t 1-L/V1), wherein S is the axial distance between the detection hole and the excitation hole, and L is the diameter of the pile body.
For neck-type defects, the neck length is determined as follows: arranging an excitation source at the defect-free depth of a pile body in an excitation hole, and arranging a detector at the same depth of the excitation source to detect the first wave time t 1; arranging an excitation source at the depth D of the pile body defect in the excitation hole, and arranging a detector in the detection hole at the same depth of the excitation source to detect the first wave time t 2; and calculating the necking length h = (t 2-t 1) (V1V 2)/(V1-V2), wherein V1 is the transmission speed of the excitation wave on the pile body, V2 is the transmission speed of the excitation wave on the soil layer around the pile body, and V2= (S-L)/(t 1-L/V1), wherein S is the axial distance between the detection hole and the excitation hole, and L is the diameter of the pile body.
The embodiments described in this specification are merely illustrative of implementations of the inventive concept and the scope of the present invention should not be considered limited to the specific forms set forth in the embodiments but rather by the equivalents thereof as may occur to those skilled in the art upon consideration of the present inventive concept.
Claims (8)
1. A method for detecting defects of an engineering pile body comprises the following steps: (1) detecting by a detector in the detection hole, and drawing a time-depth oscillogram; (2) determining whether pile body defects exist according to the time-depth oscillogram; (3) for the pile body with the defects of neck expansion and neck reduction, the other side of the pile body is provided with an excitation hole; (4) determining the transmission speed of the shock wave on the pile body; (5) and (4) detecting an excitation wave signal of the excitation hole and the transmission speed of the excitation wave in the pile body determined in the step (4) through a detector, and determining the neck-expanding length of the neck-expanding defects or the neck-contracting length of the neck-contracting defects.
2. The engineering pile body defect detection method according to claim 1, characterized in that: in the step (1), the excitation waves excited at the top of the pile or at the side surface of the top of the pile are detected at different depths of the detection hole through a detector, and a time-depth waveform diagram is drawn according to the detection signals.
3. The engineering pile body defect detection method according to claim 1, characterized in that: and (3) in the step (2), when part of region points in the time-depth oscillogram are located in the left region of the head wave travel time connecting line of the rest points, determining that the pile body has the defects of neck expansion.
4. The engineering pile body defect detection method according to claim 1, characterized in that: and (3) in the step (2), when part of region points in the time-depth oscillogram are located in the right region of the head wave travel time connecting line of the rest points, determining that the pile body has the defects of neck expansion.
5. The engineering pile body defect detection method according to claim 1, characterized in that: in the step (3), the axis of the excitation hole, the axis of the pile body and the axis of the detection hole are located on the same plane.
6. The engineering pile body defect detection method according to claim 1, characterized in that: in the step (3), for the neck-expanding defects, determining the defect depth D =sigmaDi/n, wherein Di is the depth of each point of the left area point of the head-wave travel time connecting line of the rest points, and n is the number of the left area points of the head-wave travel time connecting line of the rest points; and for the necking defects, determining the defect depth D =sigmaDi/n, wherein Di is the depth of each point of the right area point of the head wave travel time connecting line of the rest points, and n is the number of the right area points of the head wave travel time connecting lines of the rest points.
7. The engineering pile body defect detection method according to claim 1, characterized in that: and (3) setting the depth of the excitation hole to be 2-3 m longer than the defect depth D.
8. The engineering pile body defect detection method according to claim 1, characterized in that: in the step (4), an excitation wave is generated on the side face of the pile body through an excitation source, the arrival time t of the head wave is detected on the side face corresponding to the pile body, and the transmission speed V1= L/t of the excitation wave on the pile body is determined according to the diameter L of the pile body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011274489.3A CN112211236B (en) | 2020-11-15 | 2020-11-15 | Engineering pile body defect detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011274489.3A CN112211236B (en) | 2020-11-15 | 2020-11-15 | Engineering pile body defect detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112211236A true CN112211236A (en) | 2021-01-12 |
| CN112211236B CN112211236B (en) | 2022-07-26 |
Family
ID=74056878
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011274489.3A Active CN112211236B (en) | 2020-11-15 | 2020-11-15 | Engineering pile body defect detection method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112211236B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0988110A (en) * | 1995-09-21 | 1997-03-31 | Mitsubishi Heavy Ind Ltd | Method of diagnosing defect of foundation pile |
| CN101570974A (en) * | 2009-03-26 | 2009-11-04 | 浙江省建筑科学设计研究院有限公司 | Method for detecting quality of existing building foundation piles with parallel seismic method |
| CN104264718A (en) * | 2014-08-29 | 2015-01-07 | 汕头大学 | Pile foundation integrality detection method |
| CN105297790A (en) * | 2015-10-26 | 2016-02-03 | 四川省建筑科学研究院 | Existing engineering pile body integrity and defect type judgment method |
| CN105783800A (en) * | 2016-04-05 | 2016-07-20 | 重庆大学 | Method for detecting diameter of rotary jet grouting pile |
| CN109469114A (en) * | 2018-11-23 | 2019-03-15 | 中国建筑科学研究院有限公司 | A kind of method for the existing foundation pile integrity of low strain integrity testing that can eliminate superstructure influence |
| 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 |
-
2020
- 2020-11-15 CN CN202011274489.3A patent/CN112211236B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0988110A (en) * | 1995-09-21 | 1997-03-31 | Mitsubishi Heavy Ind Ltd | Method of diagnosing defect of foundation pile |
| CN101570974A (en) * | 2009-03-26 | 2009-11-04 | 浙江省建筑科学设计研究院有限公司 | Method for detecting quality of existing building foundation piles with parallel seismic method |
| CN104264718A (en) * | 2014-08-29 | 2015-01-07 | 汕头大学 | Pile foundation integrality detection method |
| CN105297790A (en) * | 2015-10-26 | 2016-02-03 | 四川省建筑科学研究院 | Existing engineering pile body integrity and defect type judgment method |
| CN105783800A (en) * | 2016-04-05 | 2016-07-20 | 重庆大学 | Method for detecting diameter of rotary jet grouting pile |
| 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 |
| CN109469114A (en) * | 2018-11-23 | 2019-03-15 | 中国建筑科学研究院有限公司 | A kind of method for the existing foundation pile integrity of low strain integrity testing that can eliminate superstructure influence |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112211236B (en) | 2022-07-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Rausche | Non-destructive evaluation of deep foundations | |
| CN108442419B (en) | Building foundation detection device and detection method | |
| WO2010006041A2 (en) | System for measuring shear stress in downhole tubulars | |
| CN112854321B (en) | Device and method for detecting integrity of cast-in-situ bored pile based on distributed acoustic sensing technology | |
| CN106770643B (en) | Method for detecting pile bottom grouting effect of expanded-bottom cast-in-place pile based on sound wave propagation principle | |
| CN104594395B (en) | A kind of method utilizing railway in operation roadbed side Bored Pile Foundation detection structure to carry out pile measurement | |
| CN110512662B (en) | Pile foundation quality detection method | |
| CN108560617B (en) | Pile body defect detection method | |
| CN112229357A (en) | Method for detecting length and quality of tubular pile | |
| CN108547332B (en) | Building pile foundation detection technology | |
| CN108625409B (en) | Civil engineering building foundation pile detection and evaluation system and method | |
| CN107869156B (en) | Parallel seismic wave method determines the detection method of foundation pile length | |
| CN112798474A (en) | Method and device for monitoring rock mass grouting diffusion range | |
| CN112211236B (en) | Engineering pile body defect detection method | |
| CN111042216B (en) | Comprehensive detection method for integrity and bearing characteristics of existing building foundation pile | |
| CN204435440U (en) | Railway in operation roadbed side Bored Pile Foundation detection architecture | |
| CN114323140A (en) | System and method for detecting pile length and integrity of precast tubular pile | |
| KR20040052961A (en) | The non-destruction test method for the spot of pipe, and the program of the read to record vehicle by the computer | |
| CN108487337B (en) | Geotechnical engineering pile foundation quality detection system | |
| CN112459142A (en) | Construction engineering supervision pile foundation defect excitation detection method | |
| CN110306606B (en) | Pile foundation quality monitoring method and device for construction process | |
| CN110528601B (en) | High-strain-based single-pile bearing capacity detection device and method for PHC-steel pipe combined pile | |
| CN114076943A (en) | Rapid automatic comprehensive detection method for urban road underground cavity | |
| CN108825136B (en) | Building pile foundation detection device | |
| CN113279435A (en) | Foundation pile quality nondestructive testing method based on side-hole diffraction wave analysis |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20220707 Address after: 250000 3-5-101, No. 650, Shunhua Road, Jinan area, China (Shandong) pilot Free Trade Zone, Jinan, Shandong Province Applicant after: Shandong Beite Construction Project Management Consulting Co.,Ltd. Address before: No.38 Haotian North Street, Fangshan District, Beijing, 102445 Applicant before: Jiang Long |
|
| TA01 | Transfer of patent application right | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |