CN110306606B - Pile foundation quality monitoring method and device for construction process - Google Patents
Pile foundation quality monitoring method and device for construction process Download PDFInfo
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Abstract
The invention provides a pile foundation quality monitoring method used in a construction process, which comprises the following steps: in the trial pile forming stage, trial pile tamping is carried out according to preset tamping parameters, and the correlation between the frequency spectrum characteristics of elastic waves generated in trial pile tamping and quality parameters reflecting construction quality is determined; in the formal construction stage, formal construction tamping is carried out according to preset tamping parameters, real-time frequency spectrum characteristics of elastic waves generated in the formal construction tamping are determined, real-time quality parameters are obtained through calculation according to the real-time frequency spectrum characteristics and the correlation, and quality monitoring is carried out on the current construction process. According to the method, a test pile is tamped by presetting tamping parameters, and the correlation between the elastic wave frequency spectrum characteristics and the quality parameters is obtained; and in the formal construction stage, calculating quality parameters according to the correlation relationship, and monitoring the bearing capacity.
Description
Technical Field
The invention relates to the field of civil engineering, in particular to a pile foundation quality monitoring method and device used in a construction process.
Background
The traditional pile foundation detection method comprises a static load test, a low strain integrity detection, a high strain detection and the like. The method aims at detection after pile forming, such as test pile detection and engineering pile detection, has respective defects, and is not beneficial to popularization and implementation in the construction process. The dead load method has the disadvantages of multiple preparation processes, long time consumption and high cost. The low strain method pile top is provided with a sensor for measuring the quality and defects of the pile body. The high strain method needs a special pile hammer, the installation and operation of the sensor are complex, the sensor is easy to break, and the cost is high.
Therefore, the invention provides a pile foundation quality monitoring method and device for a construction process.
Disclosure of Invention
In order to solve the problems, the invention provides a pile foundation quality monitoring method for a construction process, which comprises the following steps:
in the trial pile forming stage, performing trial pile tamping according to preset tamping parameters, and determining the correlation between the frequency spectrum characteristics of elastic waves generated in the trial pile tamping and quality parameters reflecting construction quality;
in the formal construction stage, formal construction tamping is carried out according to the preset tamping parameters, the real-time frequency spectrum characteristics of elastic waves generated in the formal construction tamping are determined, real-time quality parameters are obtained through calculation according to the real-time frequency spectrum characteristics and the correlation, and the quality of the current construction process is monitored.
According to an embodiment of the present invention, the step of determining the correlation between the frequency spectrum characteristic of the generated elastic wave in the trial-pile ramming and the quality parameter reflecting the construction quality further includes the following steps:
receiving elastic waves generated in the trial pile ramming, and performing spectrum analysis to obtain the spectrum characteristics;
measuring the quality parameters reflecting the construction quality according to a preset method;
and obtaining the correlation based on the frequency spectrum characteristics and the quality parameters.
According to an embodiment of the present invention, the step of calculating to obtain the real-time quality parameter according to the real-time frequency spectrum feature and the correlation, and monitoring the quality of the current construction process further includes the following steps:
substituting the real-time frequency spectrum characteristics into the correlation relationship, and calculating to obtain the real-time quality parameters reflecting the current construction quality;
and comparing the real-time quality parameters with standard quality parameters, and stopping tamping when the real-time quality parameters meet the requirements of the standard quality parameters.
According to one embodiment of the invention, the elastic waves generated in the trial-pile ramming and the official construction ramming are received by a geophone provided on the ground.
According to one embodiment of the invention, in the trial pile forming stage and/or the formal construction stage, the pile head depth is calculated according to the received elastic waves.
According to an embodiment of the present invention, the step of calculating the pile head depth according to the received elastic waves further includes the following steps:
receiving elastic waves generated in the trial pile tamping and/or the formal construction tamping and the moment when the elastic waves are received according to at least three detectors arranged on the ground;
and measuring the distances between the three detectors and the pile hole respectively, and calculating by combining the received elastic waves and the time through mathematical operation to obtain the depth of the pile head.
According to one embodiment of the invention, the method further comprises: and measuring the three-strike penetration degree according to the depth of the pile head.
According to one embodiment of the invention, the mass parameter comprises a load bearing capacity.
According to one embodiment of the present invention, the content specified in the preset tamping parameters comprises: the diameter of the column hammer, the length of the column hammer, the mass of the column hammer and the drop distance of the column hammer.
According to another aspect of the present invention, there is also provided a pile foundation quality monitoring apparatus for use in a construction process, the apparatus comprising:
the system comprises a first module, a second module and a third module, wherein the first module is used for performing trial pile tamping according to preset tamping parameters in a trial pile tamping stage and determining the correlation between the frequency spectrum characteristics of elastic waves generated in the trial pile tamping and quality parameters reflecting construction quality;
and the second module is used for performing formal construction tamping according to the preset tamping parameters in a formal construction stage, determining real-time frequency spectrum characteristics of elastic waves generated in the formal construction tamping, calculating to obtain real-time quality parameters according to the real-time frequency spectrum characteristics and the correlation relationship, and monitoring the quality of the current construction process.
According to the pile foundation quality monitoring method and device for the construction process, elastic wave detection and quality parameter detection are carried out on a test pile under the condition of preset tamping parameters, and the correlation between the elastic wave frequency spectrum characteristics and the quality parameters is obtained; in the formal construction stage, only elastic wave detection is carried out, and quality parameters are calculated according to the correlation relation, so that the purpose of monitoring the bearing capacity is achieved. In addition, the invention uses the ramming as the excitation source, and does not need to additionally arrange the excitation source. The equipment is simple and light, the sensors do not need to be embedded or mounted on the pile body and the hammer body, the construction process is not interfered, the operation is synchronously carried out along with tamping, the selection of construction process parameters can be guided, and the construction cost and time are saved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
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 shows a flow diagram of a pile foundation quality monitoring method for a construction process according to an embodiment of the invention;
FIG. 2 shows a flow chart of determining correlations in a pile foundation quality monitoring method for a construction process according to an embodiment of the invention;
FIG. 3 shows a schematic diagram of a pile foundation quality monitoring site for a construction process according to an embodiment of the invention;
fig. 4 shows a schematic diagram of pile foundation quality monitoring method for a construction process when calculating pile head depth according to an embodiment of the invention;
fig. 5 shows an elastic wave spectrum diagram when a pile foundation quality monitoring method for a construction process according to an embodiment of the invention is used for frequency spectrum analysis;
FIG. 6 is a graph showing spectral characteristics and quality parameters in a pile foundation quality monitoring method for a construction process according to an embodiment of the present invention;
FIG. 7 is a graph showing a frequency spectrum characteristic versus a quality parameter under a preset ramming parameter in a pile foundation quality monitoring method for a construction process according to an embodiment of the present invention; and
fig. 8 shows a block diagram of a pile foundation quality monitoring apparatus for a construction process according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
For the construction process, the specification only refers to the monitoring of the driven precast pile, and the carrier pile has no method specified by the specification. According to the technical specification of JGJ106-2014 building foundation pile detection, pile foundation detection can be divided into the following different stages:
1. before construction: and (4) detecting the test piles, providing basis for design, and determining the ultimate bearing capacity of the single pile.
2. After construction: and (4) acceptance detection and engineering pile detection, which provides basis for acceptance and determines single pile bearing capacity and pile body integrity detection.
3. The construction process comprises the following steps: and (4) carrying out quality detection and monitoring according to engineering requirements. And (3) monitoring the piling process of trial piling by a high-strain method when the driving type precast pile is required. And monitoring the pile body stress and hammering energy transfer ratio when the precast pile is driven, and providing a basis for selecting pile sinking process parameters and pile length.
For the construction process, the specification only refers to the monitoring of the driven precast pile, and the carrier pile has no method specified by the specification. In the specification, the pile foundation detection method is shown in the following table 1.
The traditional pile foundation detection method comprises a static load test, a low strain integrity detection, a high strain detection and the like. The end of the carrier pile is provided with a carrier, the hammering energy required by high strain is large, the method is not generally adopted for detection, and mainly the static load test and the low strain integrity detection of the carrier pile are carried out.
The static load test is a detection means which loads a pile foundation or a composite foundation in a grading manner by taking a pile or an anchor pile as a counterforce device and a jack as a loading means, and simulates the stress of the pile or the composite foundation to detect whether the pile or the composite foundation meets the engineering design requirements. The method generally comprises engineering test pile detection and engineering pile acceptance detection.
The method adopted by the low-strain integrity detection is a reflection wave method, and the reflection wave method is a nondestructive detection method for analyzing and judging the quality of the pile body and the pile bottom concrete through the reflection wave signal at the pile bottom by utilizing the propagation rule of waves in the solid. The method utilizes a heavy hammer to knock on the pile top to generate vibration waves, and when the vibration waves are transmitted in a solid, when a transmission medium is changed or a transmission section is changed, a part of waves are reflected back to the pile top. The defects of the pile body are analyzed by performing mathematical integration, screening, separation and amplification on signals acquired by the pile top sensor.
The high strain method piling dynamic monitoring is divided into 3 processes of sensor installation, test system debugging, data acquisition and analysis and the like. 1. The installation position of the sensor is determined according to the length of the pile hammer sleeve, and the sensor is ensured to be positioned between the lower edge of the pile hammer sleeve and the upper edge of the pile cutting mark, so that stress wave information can be effectively monitored. And interference positions such as pile extension, welding seams, the lower edge of the hammer sleeve, the change of the cross-sectional area of the pile and the like are avoided when the sensor is installed. And symmetrically drilling holes on the circumference which is about 5m away from the pile top by adopting an electromagnetic drill, and respectively fixing the acceleration sensor, the stress sensor and the wireless transmitter. Before hoisting, a sensor and a wireless transmitter are installed. 2. And monitoring and debugging by adopting a test system. 3. After the pile driver works, data acquisition and analysis processing are carried out in the pile driving process.
The three methods are all aimed at detection after pile forming, such as test pile detection and engineering pile detection, have respective defects and are not beneficial to being popularized to the implementation in the construction process.
TABLE 1 purpose and method of detection
In the prior art, a method for detecting bearing capacity of a carrier pile uses a heavy hammer to hammer the carrier pile, controls hammering energy to enable a pile body to generate vertical displacement, and judges the vertical bearing capacity of the pile according to a measured displacement value and soil property of a pile end bearing layer.
1) Reinforcing and protecting the pile head of the carrier pile to be detected;
2) lifting a certain height above the pile head by using a heavy hammer, then freely dropping and striking the pile head, controlling hammering energy to enable a pile body to generate downward vertical displacement, and measuring and recording the displacement value;
3) repeating the hammering operation in the step 2), stopping hammering when the total energy of multiple times of hammering reaches a set value, and recording the total displacement numerical value of the pile body;
4) and (4) judging the equivalent calculation area Ae value of the carrier through the total displacement numerical value and the soil property of the pile end bearing layer, and calculating the vertical bearing capacity of the pile according to the Ae value.
In the prior art, a displacement sensor is arranged at a pile head, so that the displacement sensor is easy to damage and needs to be frequently disassembled and assembled; the hammering energy needs to be controlled, the displacement and the soil property of a pile end bearing layer need to be measured, and the operation is complex; only the vertical bearing capacity can be measured; the construction process is disturbed, and the cooperation of construction parties is needed.
Fig. 1 shows a flow chart of a pile foundation quality monitoring method for a construction process according to an embodiment of the invention.
As shown in fig. 1, in step S101, during trial pile forming, trial pile tamping is performed according to preset tamping parameters, and a correlation between a frequency spectrum characteristic of an elastic wave generated during trial pile tamping and a quality parameter reflecting construction quality is determined.
Preferably, the correlation may be determined by a method as shown in fig. 2. First, in step S201, an elastic wave generated during trial pile driving is received, and spectral analysis is performed to obtain a spectral feature. Then, in step S202, quality parameters reflecting construction quality are measured according to a preset method. Finally, in step S203, a correlation is obtained based on the spectral feature and the quality parameter.
As shown in fig. 1, in step S102, in the formal construction phase, formal construction tamping is performed according to preset tamping parameters, real-time frequency spectrum characteristics of elastic waves generated in the formal construction tamping are determined, real-time quality parameters are calculated according to the real-time frequency spectrum characteristics and the correlation, and quality monitoring is performed on the current construction process.
Preferably, the real-time frequency spectrum characteristics are brought into the correlation relationship, and real-time quality parameters reflecting the current construction quality are obtained through calculation. And comparing the real-time quality parameters with the standard quality parameters, and stopping tamping when the implementation quality parameters meet the requirements of the standard quality parameters.
Preferably, the elastic waves generated in the trial-pile tamping and the formal construction tamping are received by a geophone disposed on the ground.
Further, in the trial pile forming stage and/or the formal construction stage, the pile head depth is calculated according to the received elastic waves.
Specifically, the pile head depth is calculated by the following method:
firstly, according to at least three detectors arranged on the ground, receiving elastic waves generated in trial pile tamping and/or formal construction tamping and the time when the elastic waves are received.
And then, measuring the distances between the three detectors and the pile hole respectively, and calculating by combining the received elastic waves and the time through mathematical operation to obtain the depth of the pile head.
In one embodiment, further comprising: and (4) measuring the three-strike penetration according to the depth of the pile head.
Preferably, the mass parameter comprises a load bearing capacity.
In one embodiment, the content specified in the preset tamping parameters comprises: the diameter of the column hammer, the length of the column hammer, the mass of the column hammer and the drop distance of the column hammer.
Fig. 3 shows a schematic diagram of a pile foundation quality monitoring site for a construction process according to an embodiment of the invention.
Figure 3 shows a schematic view of the construction site facing the piling of the carrier pile. For the 1 st pile, the frequency spectrum characteristic E is obtained by elastic wave detection, the quality parameter R which more directly reflects the construction quality is measured by a static load method, and the correlation of the E and the R is established. And when other subsequent piles are constructed, the parameter R can be calculated by only measuring the spectral characteristic E, so that the construction quality is judged, and the construction is assisted. The compactness, the static sounding and the like in the quality parameters R are high in complexity, so that a variable E related to the compactness, the static sounding and the like is measured to indirectly measure R. It should be noted that the mass parameter includes a load bearing capacity.
As shown in fig. 3, a detector needs to be arranged on the ground near the pile hole, and the number of the detectors varies according to different monitoring targets, and may be 1 or multiple detectors.
When the test pile elastic wave field detection is carried out, a detection instrument is started, the column hammer is used for tamping to serve as a transmission source to generate elastic waves, a wave detector receives transmission wave signals from the bottom of a pile, and the transmission wave signals are repeatedly excited and received along with the multiple tamping of the column hammer. In addition, during the tamping process in the test pile stage, a quality parameter R is measured.
When the number of the detectors is at least 3, the depth of the pile head can be obtained through analysis of elastic wave data. As shown in fig. 4, a schematic view when calculating the pile head depth is shown. It should be noted that the mass parameter includes a load bearing capacity.
As shown in fig. 4, at least 3 receivers of data are required to calculate the pile head depth, using the waveform of any single tamping. The depth H of pile head to be measured is LMNThe data that the detector can measure is as follows: and the time of the waveform received by the detectors A, B and C.
Assuming that the wave velocity of the elastic wave in the underground space of the triangular area is uniform, the following equation set can be obtained:
V×TNA＝LNA
V×TNB＝LNB
V×TNC＝LNC
wherein V represents the wave velocity, TNA、TNB、TNCRespectively, the propagation times, L, of the elastic waves in NA, NB, and NCNA、LNB、LNCRespectively representing the linear distances between the detector A, the detector B and the detector C and the position N (pile head).
Because the detector may not be capable of measuring the accurate trigger time, the accurate time T of the waveform in NA, NB and NCNA、TNB、TNCCannot be obtained, but 2 time differences can be obtained according to the measured received waveform time。
△T1＝TNB-TNA
△T2＝TNC-TNA
Where Δ T1 represents the time difference between receivers B and a, and Δ T2 represents the time difference between receivers C and a.
The system of equations may be changed to:
V×TNA＝LNA
V×(△T1+TNA)＝LNB
V×(△T2+TNA)＝LNC
mixing L withNA、LNB、LNCAnd is represented by H, such as,
the system of equations may change to:
the unknowns of the equation set are V, TNAH, solving the H by 3 unknowns of the above 3 equations by using mathematical operation.
In addition, the received elastic waves can be subjected to Fourier transform and other processing, spectrum analysis is carried out, and the frequency spectrum characteristic E of each tamping can be calculated. And when the change value delta E of the two times of column hammer tamping is smaller than a preset threshold value, continuing tamping without practical significance, and stopping tamping.
The spectral feature E is exemplified as follows, but not limited to the following cases:
single peak: dominant frequency.
Double peak: the absolute value of the difference between the two peaks.
In addition, the spectral features include: energy variation, dominant frequency, and peak shift.
And obtaining a correlation curve of R and E in the tamping process through the frequency spectrum characteristic E and the measured parameter R. Assuming that the waveform received by the elastic wave is unimodal, the spectral characteristic is denoted by E. As shown in fig. 5 (frequency on the horizontal axis and amplitude on the vertical axis), the frequency of the dominant frequency decreases with ramming. R increases with ramming and E increases with ramming, with positive correlation, as shown in fig. 6. From this correlation, a correlation curve can be derived for both at a preset tamping parameter, as shown in FIG. 7, and R can be calculated from E. It should be noted that the mass parameter includes a load bearing capacity. The preset ramming parameters include the diameter of the column hammer, the length of the column hammer, the mass of the column hammer, the falling distance of the column hammer and the like.
Considering the reason of construction vibration effect: in the construction process of the carrier pile, due to the tamping effect of the column hammer, shock waves can be generated, and if the tamping energy is too large, the influence on buildings can be possibly caused.
In the formal construction process, the invention can realize dynamic monitoring. And (5) carrying out the tamping construction of the carrier pile according to preset tamping parameters. Then, elastic wave detection is performed along with the construction process. And finally, calculating the bearing capacity R according to the corresponding correlation curve of the E and the R, and stopping tamping when the requirement is met.
In addition, a plurality of detectors can be arranged on a construction site, and construction of a plurality of carrier piles can be monitored simultaneously. It should be noted, however, that there cannot be two hammers simultaneously landing.
The invention can be used for the hole bottom in the hole forming process and the carrier of the pile head of the carrier pile, is not limited to the carrier pile, and can also be used for carrying out bearing capacity detection on other cast-in-place concrete piles and precast concrete piles. The pile foundation comprises a building construction pile foundation and also comprises other construction engineering foundation piles such as roads, railways, bridges and the like. The number of the detectors can be changed, and if the depth of the pile head is measured, the number of the detectors is at least 3.
In addition, civil engineering field regulations to be adhered to during construction include: the technical specification for detecting the foundation piles of the building (JGJ106-2014), the technical specification for detecting the foundation piles of the railway engineering (TB 10218 and 2008) and the technical specification for dynamically measuring the foundation piles of the road engineering (JTG/T F81-01-2004).
As mentioned above, the invention monitors the bearing capacity of the pile end carrier in the tamping process, rather than the detection after pile forming, and the remedial measures are difficult and complicated if problems are found after pile forming. The method adopts an elastic wave transmission method, but does not need to additionally arrange a transmitting source, and uses a column hammer for ramming as the transmitting source. A sensor is not needed to be arranged on the pile body or the hammer body, so that the bearing capacity can be detected, and parameter selection and construction process can be guided.
Fig. 8 shows a block diagram of a pile foundation quality monitoring apparatus for a construction process according to an embodiment of the present invention. As shown in fig. 8, the monitoring apparatus 800 includes: a first module 801 and a second module 802.
The first module 801 is configured to perform trial pile tamping in the trial pile forming stage according to preset tamping parameters, and determine a correlation between a frequency spectrum characteristic of an elastic wave generated in the trial pile tamping and a quality parameter reflecting construction quality.
The second module 802 is configured to perform formal construction tamping in a formal construction stage according to preset tamping parameters, determine real-time frequency spectrum characteristics of elastic waves generated in the formal construction tamping, calculate real-time quality parameters according to the real-time frequency spectrum characteristics and the correlation relationship, and perform quality monitoring on the current construction process.
In one embodiment, the monitoring device may include a plurality of detectors, a staging database, a data transmission module, a field terminal, and a server. The field terminal is connected with the server, the field terminal is respectively connected with the detector and the temporary storage database through the data transmission module, and the output end of the detector is connected to the input end of the temporary storage database.
The detector and the field terminal can ensure real-time, dynamic and non-landing transmission of detection data through a wireless adapter, a USB communication module or a serial port communication module, so as to ensure the authenticity of the detection data; and a temporary storage database is used for data caching, so that the data integrity, timeliness and transmission stability are ensured.
In summary, according to the pile foundation quality monitoring method and device for the construction process, elastic wave detection and quality parameter detection are performed on the test pile under the preset tamping parameters, so that the correlation between the elastic wave frequency spectrum characteristics and the quality parameters is obtained; in the formal construction stage, only elastic wave detection is carried out, and quality parameters are calculated according to the correlation relation, so that the purpose of monitoring the bearing capacity is achieved. In addition, the invention uses the ramming as the excitation source, and does not need to additionally arrange the excitation source. The equipment is simple and light, the sensors do not need to be embedded or mounted on the pile body and the hammer body, the construction process is not interfered, the operation is synchronously carried out along with tamping, the selection of construction process parameters can be guided, and the construction cost and time are saved.
It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures, process steps, or materials disclosed herein but are extended to equivalents thereof as would be understood by those ordinarily skilled in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A pile foundation quality monitoring method for a construction process is characterized by comprising the following steps:
in the trial pile forming stage, performing trial pile tamping according to preset tamping parameters, and determining the correlation between the frequency spectrum characteristics of elastic waves generated in the trial pile tamping and quality parameters reflecting construction quality;
in the formal construction stage, formal construction tamping is carried out according to the preset tamping parameters, the real-time frequency spectrum characteristics of elastic waves generated in the formal construction tamping are determined, real-time quality parameters are obtained through calculation according to the real-time frequency spectrum characteristics and the correlation, and the quality of the current construction process is monitored.
2. The method of claim 1, wherein the step of determining the correlation between the spectral characteristics of the elastic waves generated in the trial compaction and the quality parameters reflecting the construction quality further comprises the steps of:
receiving elastic waves generated in the trial pile ramming, and performing spectrum analysis to obtain the spectrum characteristics;
measuring the quality parameters reflecting the construction quality according to a preset method;
and obtaining the correlation based on the frequency spectrum characteristics and the quality parameters.
3. The method of claim 1, wherein the step of calculating real-time quality parameters according to the real-time frequency spectrum characteristics and the correlation, and monitoring the quality of the current construction process further comprises the steps of:
substituting the real-time frequency spectrum characteristics into the correlation relationship, and calculating to obtain the real-time quality parameters reflecting the current construction quality;
and comparing the real-time quality parameters with standard quality parameters, and stopping tamping when the real-time quality parameters meet the requirements of the standard quality parameters.
4. The method of any one of claims 1-3, wherein the elastic waves generated in the trial tamping and the official construction tamping are received by a geophone disposed at the ground surface.
5. The method of claim 4, further comprising: and in the trial pile forming stage and/or the formal construction stage, calculating to obtain the pile head depth according to the received elastic waves.
6. The method of claim 5, wherein the step of calculating the pile head depth from the received elastic waves further comprises the steps of:
receiving elastic waves generated in the trial pile tamping and/or the formal construction tamping and the moment when the elastic waves are received according to at least three detectors arranged on the ground;
and measuring the distances between the three detectors and the pile hole respectively, and calculating by combining the received elastic waves and the time through mathematical operation to obtain the depth of the pile head.
7. The method of any one of claims 5-6, further comprising: and measuring the three-strike penetration degree according to the depth of the pile head.
8. The method of claim 1, wherein the mass parameter comprises a load bearing capacity.
9. The method of claim 1, wherein the content specified in the preset tamping parameters comprises: the diameter of the column hammer, the length of the column hammer, the mass of the column hammer and the drop distance of the column hammer.
10. A pile foundation quality monitoring device for use in a construction process, the device comprising:
the system comprises a first module, a second module and a third module, wherein the first module is used for performing trial pile tamping according to preset tamping parameters in a trial pile tamping stage and determining the correlation between the frequency spectrum characteristics of elastic waves generated in the trial pile tamping and quality parameters reflecting construction quality;
and the second module is used for performing formal construction tamping according to the preset tamping parameters in a formal construction stage, determining real-time frequency spectrum characteristics of elastic waves generated in the formal construction tamping, calculating to obtain real-time quality parameters according to the real-time frequency spectrum characteristics and the correlation relationship, and monitoring the quality of the current construction process.
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