CN107190789B - A kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles - Google Patents
A kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles Download PDFInfo
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- CN107190789B CN107190789B CN201710558313.2A CN201710558313A CN107190789B CN 107190789 B CN107190789 B CN 107190789B CN 201710558313 A CN201710558313 A CN 201710558313A CN 107190789 B CN107190789 B CN 107190789B
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- 238000012360 testing method Methods 0.000 title claims abstract description 45
- 238000010187 selection method Methods 0.000 title claims abstract description 35
- 238000010009 beating Methods 0.000 claims abstract description 51
- 239000007787 solid Substances 0.000 claims abstract description 47
- 238000000034 method Methods 0.000 claims abstract description 28
- 239000000523 sample Substances 0.000 claims description 15
- 230000010365 information processing Effects 0.000 claims description 13
- 230000010355 oscillation Effects 0.000 claims description 11
- 230000002452 interceptive effect Effects 0.000 claims description 8
- 235000014121 butter Nutrition 0.000 claims description 3
- 239000003292 glue Substances 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 21
- 241000282693 Cercopithecidae Species 0.000 description 12
- 239000000470 constituent Substances 0.000 description 11
- 238000005070 sampling Methods 0.000 description 11
- 230000007547 defect Effects 0.000 description 9
- 239000002689 soil Substances 0.000 description 9
- 238000005259 measurement Methods 0.000 description 5
- 240000002853 Nelumbo nucifera Species 0.000 description 3
- 235000006508 Nelumbo nucifera Nutrition 0.000 description 3
- 235000006510 Nelumbo pentapetala Nutrition 0.000 description 3
- 238000011016 integrity testing Methods 0.000 description 3
- 238000009527 percussion Methods 0.000 description 3
- 210000001367 artery Anatomy 0.000 description 2
- 230000002085 persistent effect Effects 0.000 description 2
- 210000003462 vein Anatomy 0.000 description 2
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 239000012491 analyte Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Classifications
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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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- Mining & Mineral Resources (AREA)
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- Piles And Underground Anchors (AREA)
Abstract
The present invention proposes a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles, and this method comprises the following steps：Step A, the determination of load pulsewidth：On the solid stake top surface of building, the first beating point is set, and the first signal pickup assembly is installed in preset range centered on first beating point, when receiving in the hammer action of first beating point, the first measuring point signal from first signal pickup assembly is obtained, and load pulsewidth is determined by the first measuring point signal；Step B, the determination of three-dimensional interference signal pulsewidth：In the solid stake top centre of surface of building, the second beating point is set, second signal harvester is installed in the measuring point that three-dimensional interference signal intensity is more than preset strength value, when receiving in the hammer action of the second beating point, the second measuring point signal from second signal harvester is obtained, and three-dimensional interference signal pulsewidth is determined based on the second measuring point signal；Step C, load pulsewidth is selected.
Description
Technical field
The present invention relates to building analyte detection fields, and in particular to a kind of load pulsewidth selecting party of Low Strain Dynamic Testing of Piles
Method.
Background technology
Existing common the low of building filled circles stake should detect change method, low in the application of stake top centre of surface using pile monkey
The transient batting of energy, the shock wave for tapping generation are propagated downwards along pile body, and when interface or the stake bottom that encounter impedance variations generates
Reflection, back wave is installed in a certain position in stake top surface radius, and (the three-dimensional smaller position of interference strength or three-dimensional interference are minimum
Point, related specifications provide in 2/3 vicinity of radius) single probe receive, according to the characteristics of signals of back wave judge pile body
Quality.
About the selection of load pulsewidth, presently mainly on the basis of three-dimensional interferes smallest point sampling method, timber pile is proposed
Using the sledgehammer that load pulsewidth is larger, paxilla uses the relatively small hand hammer of load pulsewidth.
But it is had the following problems in above-mentioned load pulsewidth selection method：
1, the test method of pile monkey load pulsewidth needs to improve：
We often sample at the position far from beating point certain distance in the load pulsewidth for determining pile monkey at this stage
(at 2/3 of the radius as defined in specification), and using the approximate bell pulse in signal front end as incoming signal.But this position
The incoming signal set actually has received the influence of foundation pile radial vibration mode, and the width of the bell pulse is not true
Load pulsewidth.
2, there are contradictions between three-dimensional interference signal intensity and defect resolution：
It is tapped using the larger wideband hammer of load pulsewidth, the intensity of three-dimensional interference signal, still, load can be reduced
Pulsewidth is bigger, lower to the resolution ratio of pile defect, to improve the resolution ratio of defect, it would be desirable to relatively narrow using pulsewidth
Hammer.
3, the narrow signal characteristic for leading to three-dimensional interference signal of load pulsewidth changes：
When load pulsewidth is narrow, the three-dimensional interference signal in signal, significant changes will occur for form, before signal
Section, in fact it could happen that amplitude bigger, the higher three-dimensional interference signal of frequency, that is, three-dimensional interference signal is no longer that frequency and form are steady
Fixed oscillator signal, moreover, at this point, stake top surface no longer has stable three-dimensional interference smallest point, that is, this amplitude bigger,
The higher three-dimensional interference signal of frequency, can not be avoided or eliminated by the selection of measuring point.At this point, existing low strain integrity testing method
Basis, three-dimensional interference smallest point sampling method failure.
So, it is desirable to provide a kind of load pulsewidth selection that can take into account defect resolution and three-dimensional interference signal elimination simultaneously
Method.
Invention content
For the defects in the prior art, the present invention proposes a kind of load pulsewidth selecting party of Low Strain Dynamic Testing of Piles
Method, it can take into account avoiding and eliminating for defect resolution and three-dimensional interference signal, realize how to be selected for different foundation piles simultaneously
The corresponding suitable pile monkey of load pulsewidth is selected, to improve test signal quality, help more accurately judges that building is solid
The integrality of stake pile body, this method can help to instruct the making of pile monkey simultaneously.
Specifically, the present invention proposes embodiment in detail below：
The embodiment of the present invention proposes a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles, and this method is applied to build
Object solid pile pile body is built, this method comprises the following steps：
Step A, the determination of load pulsewidth：The first beating point is set on the solid stake top surface of building, and described the
First signal pickup assembly is installed, when receiving the percussion in first beating point in preset range centered on one beating point
When action, the first measuring point signal from first signal pickup assembly is obtained, and determine by the first measuring point signal
Load pulsewidth；
Step B, the determination of three-dimensional interference signal pulsewidth：In solid the second percussion of stake top centre of surface setting of building
Point installs second signal harvester, when receiving second in the measuring point that three-dimensional interference signal intensity is more than preset strength value
When the hammer action of beating point, the second measuring point signal from second signal harvester is obtained, and be based on second measuring point
Signal determines three-dimensional interference signal pulsewidth；
Step C, load pulsewidth is selected：Pulsewidth is selected to be more than the load pulsewidth of three-dimensional interference signal pulsewidth；Or selection makes
Three-dimensional interference signal oscillation characteristics meet pre-determined stability feature, do not occur amplitude in predeterminable area before the signal and frequency is super
Cross the load pulsewidth of the three-dimensional interference signal of pre-determined stability characteristic value；Or selection pulsewidth and the product of stake top surface wave velocity of wave are more than
The load pulsewidth of foundation pile diameter.
In a specific embodiment, in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles,
The load pulsewidth be the first measuring point signal in be approximately sinusoidal incoming signal period or wavelength.
In a specific embodiment, in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles,
The three-dimensional interference signal pulsewidth is the period of three-dimensional interference signal or wavelength in the second measuring point signal.
In a specific embodiment, in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles,
The building solid pile pile body is specially building solid circles foundation pile.
In a specific embodiment, in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles,
The hammer action is to carry out vertical tap by power hammer or power stick to generate.
In a specific embodiment, in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles,
First beating point is any position including stake top centre of surface point on the solid stake top surface of the building；Institute
State the central point that the second beating point is the solid stake top surface of the building.In a specific embodiment, described
In a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles, first signal pickup assembly and/or the second signal
Harvester be probe or sensor, first signal pickup assembly and/or the second signal harvester by glue,
The stickums such as butter or plasticine are pasted onto the solid stake top surface of the building.
In a specific embodiment, in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles,
First signal pickup assembly and/or the second signal harvester are connected with information processing unit；Described information processing
Device is specially Low Strain Dynamic Testing of Piles instrument.
In a specific embodiment, in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles,
When the load pulsewidth or three-dimensional interference signal pulsewidth correspond to the period, wavelength is corresponded to after information processing.
In a specific embodiment, in a kind of method of the load pulsewidth of Low Strain Dynamic Testing of Piles selection
In, the frequency of three-dimensional interference signal asks inverse to obtain according to three-dimensional interference signal pulsewidth；Or it is estimated according to following expression formula：
Wherein：νx、Cx、Dx、Respectively wait asking the foundation pile of three-dimensional interference signal frequency concrete Poisson's ratio,
One-dimensional longitudinal wave velocity (m/s), stake diameter (m) and three-dimensional interfering frequency (Hz)；
ν0、C0、D0、It is the concrete Poisson's ratio for having demarcated or having measured foundation pile, one-dimensional longitudinal wave velocity (m/ respectively
S), stake diameter (m) and three-dimensional interfering frequency (Hz)；
The three-dimensional interference signal pulsewidth estimated by foundation pile longitudinal wave velocity divided by the three-dimensional interference signal frequency estimated.
With this, the embodiment of the present invention proposes a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles, and this method is answered
For building solid pile pile body, this method comprises the following steps：Step A, the determination of load pulsewidth：In building solid pile stake
The first beating point is arranged in top surface, and the first signal acquisition dress is installed in preset range centered on first beating point
It sets, when receiving in the hammer action of first beating point, obtains first from first signal pickup assembly and survey
Point signal, and load pulsewidth is determined by the first measuring point signal；Step B, the determination of three-dimensional interference signal pulsewidth：It is building
The second beating point is arranged in the solid stake top centre of surface of object, is installed in the measuring point that three-dimensional interference signal intensity is more than preset strength value
Second signal harvester is obtained when receiving in the hammer action of the second beating point from second signal harvester
Second measuring point signal, and three-dimensional interference signal pulsewidth is determined based on the second measuring point signal；Step C, load pulsewidth is selected：Choosing
Select the load pulsewidth that pulsewidth is more than three-dimensional interference signal pulsewidth；Or selection makes three-dimensional interference signal oscillation characteristics meet to preset surely
Determine feature, do not occur amplitude before the signal in predeterminable area and frequency be more than pre-determined stability characteristic value three-dimensional interference signal
Load pulsewidth；Or selection pulsewidth is more than the load pulsewidth of foundation pile diameter with the product of stake top surface wave velocity of wave.The present invention passes through
Beating point is set on building solid stake top surface, signal pickup assembly is installed close to beating point, obtains accurate pile monkey and strikes
Load pulsewidth caused by concrete is hit, this lays a good foundation for the selection and making of pile monkey.Meanwhile it is three-dimensional dry to give test
Disturb the expression formula of the method and the three-dimensional interference signal frequency of estimation of signal pulsewidth, the method for giving the selection of load pulsewidth.It is above-mentioned
Triplicity, by being sampled at the three-dimensional interference smallest point of stake top radius, can reach under conditions of ensuring defect resolution
To farthest avoiding or eliminating three-dimensional interference signal, the purpose of test signal quality is improved, to help more accurately
Judge the integrality of building solid pile pile body.In Practical Project, the present invention is solved for different foundation piles, how to be selected
Select the problem of suitable power hammers this problem, i.e. pile monkey matching into shape.
Description of the drawings
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be to needed in the embodiment attached
Figure is briefly described, it should be understood that the following drawings illustrates only certain embodiments of the present invention, therefore is not construed as pair
The restriction of range for those of ordinary skill in the art without creative efforts, can also be according to this
A little attached drawings obtain other relevant attached drawings.
Fig. 1 is a kind of flow diagram of the load pulsewidth selection method of Low Strain Dynamic Testing of Piles of the present invention.
Fig. 2 is the structural representation that a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles of the present invention determines load pulsewidth
Figure.
Fig. 3 be structural schematic diagram shown in Fig. 2 concrete longitudinal wave velocity 4050m/s, Poisson's ratio 0.28, stake diameter 2.9m,
Under the conditions of the long 25m of stake, load pulsewidth 1.6ms, taps at stake end face center, adopted at the 0.07R (radius) close to beating point
Sample be approximately sinusoidal incident pulse and at the sample 0.67R that specification is recommended sample be approximately bell pulse
Incident pulse.
Fig. 4 is the knot that three-dimensional interference pulsewidth is determined in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles of the present invention
Structure schematic diagram.
Fig. 5 be structural schematic diagram shown in Fig. 4 concrete longitudinal wave velocity 4050m/s, Poisson's ratio 0.28, stake diameter 2.9m,
The long 25m of stake, load pulsewidth 1.6ms under the conditions of no soil layer, are tapped in stake end face center, 0.0R, 0.33R on arbitrary radius,
When being sampled at 0.4R, 0.54R, 0.67R, 0.75R, R, the contrast schematic diagram of calculating speed signal.
Fig. 6 be structural schematic diagram shown in Fig. 4 concrete longitudinal wave velocity 4050m/s, Poisson's ratio 0.28, stake diameter 2.9m,
The long 25m of stake, load pulsewidth are respectively 0.409ms, 0.619ms, 1.239ms, 1.6ms, under the conditions of no soil layer, in stake end face center
It taps, when being sampled at the 0.67R on arbitrary radius, the contrast schematic diagram of calculating speed signal.
Fig. 7 be structural schematic diagram shown in Fig. 4 concrete longitudinal wave velocity 4050m/s, Poisson's ratio 0.28, stake diameter 2.9m,
The long 25m of stake, load pulsewidth 0.619ms under the conditions of no soil layer, are tapped in stake end face center, 0.39R on arbitrary radius,
When being sampled at 0.53R, 0.67R, the contrast schematic diagram of calculating speed signal.
Fig. 8 A Fig. 8 D are concrete longitudinal wave velocity 4050m/s, Poisson's ratio 0.28, stake diameter 2.9m, the long 25m of stake, load pulsewidth
Respectively 0.409ms, 0.619ms, 1.239ms, 1.6ms when, under the conditions of no soil layer, tapped in stake end face center, load action
Middle point moment and finish time, pass through the comparison of sum velocity vector cloud atlas of the vertical section of stake axis in stake top near zone
Schematic diagram.
Marginal data：
100- reality section circle foundation piles；200- exciting devices；300- information collecting devices；
400- information processing units
Specific implementation mode
Hereinafter, the various embodiments of the disclosure will be described more fully.The disclosure can have various embodiments, and
It can adjust and change wherein.It should be understood, however, that：There is no the various embodiments of the disclosure are limited to spy disclosed herein
Determine the intention of embodiment, but the disclosure should be interpreted as in the spirit and scope for covering the various embodiments for falling into the disclosure
All adjustment, equivalent and/or alternative.
Hereinafter, disclosed in the term " comprising " that can be used in the various embodiments of the disclosure or " may include " instruction
Function, operation or the presence of element, and do not limit the increase of one or more functions, operation or element.In addition, such as existing
Used in the various embodiments of the disclosure, term " comprising ", " having " and its cognate are meant only to indicate special characteristic, number
Word, step, operation, the combination of element, component or aforementioned item, and be understood not to exclude first one or more other
Feature, number, step, operation, the combination of element, component or aforementioned item presence or increase one or more features, number,
Step, the possibility of operation, the combination of element, component or aforementioned item.
In the various embodiments of the disclosure, it includes listing file names with to state "or" or " at least one of A or/and B "
Any combinations of word or all combinations.For example, statement " A or B " or " at least one of A or/and B " may include A, may include
B may include A and B both.
The statement (" first ", " second " etc.) used in the various embodiments of the disclosure can be modified in various implementations
Various constituent element in example, but respective sets can not be limited into element.For example, presented above be not intended to limit the suitable of the element
Sequence and/or importance.The purpose presented above for being only used for differentiating an element and other elements.For example, the first user fills
It sets and indicates different user device with second user device, although the two is all user apparatus.For example, not departing from each of the disclosure
In the case of the range of kind embodiment, first element is referred to alternatively as second element, and similarly, second element is also referred to as first
Element.
It should be noted that：It, can be by the first composition member if a constituent element ' attach ' to another constituent element by description
Part is directly connected to the second constituent element, and " connection " third can be formed between the first constituent element and the second constituent element
Element.On the contrary, when a constituent element " being directly connected to " is arrived another constituent element, it will be appreciated that in the first constituent element
And second third constituent element is not present between constituent element.
The term used in the various embodiments of the disclosure is used only for the purpose of describing specific embodiments and not anticipates
In the various embodiments of the limitation disclosure.As used herein, singulative is intended to also include plural form, unless context is clear
Chu it is indicated otherwise.Unless otherwise defined, otherwise all terms (including technical terms and scientific terms) used herein have
There is meaning identical with the various normally understood meanings of embodiment one skilled in the art of the disclosure.The term
(term such as limited in the dictionary generally used) is to be interpreted as having and situational meaning in the related technical field
Identical meaning and the meaning that Utopian meaning or too formal will be interpreted as having, unless in the various of the disclosure
It is clearly defined in embodiment.
Embodiment 1
A kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles, this method are applied to building solid pile pile body, such as
Shown in Fig. 1, this method comprises the following steps：
The determination of step 101, load pulsewidth：The first beating point is set on the solid stake top surface of building, and described
First signal pickup assembly is installed, when receiving striking in first beating point in preset range centered on the first beating point
When hitting action, the first measuring point signal from first signal pickup assembly is obtained, and true by the first measuring point signal
Constant load pulsewidth；
In a specific embodiment, it is approximately sinusoidal that the load pulsewidth, which is in the first measuring point signal,
The period of incoming signal or wavelength.
Specifically, load pulsewidth is determined by obtaining the fore-end of the first measuring point signal, specifically, the first measuring point is believed
Number fore-end be approximately sinusoidal incidence rate signal, specifically, in processing procedure, the sinusoidal period
Or wavelength is load pulsewidth.
Specifically, beating point can be located at any position including stake top centre of surface point, however, it is desirable to ensure tight
Adjacent beating point installs signal pickup assembly.That is, referring to close to beating point in preset range centered on first beating point
Measuring point, specific range values can be needed according to the experience of measurement and the environment specifically measured and measurement to carry out flexibly
Setting.When specific operation, premised on not interfering hammer action to implement, signal pickup assembly paste position is got over closer to beating point
It is good.
In one embodiment of this invention, on the building solid circles foundation pile pile body, beating point is located at stake top table
At the center of face, the first signal acquisition point is located at 0.07R (close to pile monkey outer diameter, i.e., close to beating point) and 0.67R (specification recommendation
Sample), it specifically may refer to Fig. 3.
It is appreciated that the building solid pile, can be also other shapes in addition to cylindrical pile body, such as polygonal solid stake,
As long as a kind of i.e. all building solid piles that can be related to of load pulsewidth selection method of Low Strain Dynamic Testing of Piles of the invention
Belong to the design of the present invention.
The determination of step 102, three-dimensional interference signal pulsewidth：In solid the second percussion of stake top centre of surface setting of building
Point installs second signal harvester, when receiving second in the measuring point that three-dimensional interference signal intensity is more than preset strength value
When the hammer action of beating point, the second measuring point signal from second signal harvester is obtained, and be based on second measuring point
Signal determines three-dimensional interference signal pulsewidth；
In a specific embodiment, beating point is located at stake top centre of surface, and certainly, beating point can also be located close to
Position near stake top centre of surface point, that is, allow slightly offset from pile center's measuring point, specifically slightly offset from may range from
The range that the engineering staff of profession rule of thumb understands.
Specifically, when determining three-dimensional interference signal pulsewidth, three-dimensional interference signal is more than that the measuring point of preset strength value refers to, from
The positions R (0.67-0.5 υ) certain distance (R is foundation pile radius) is opened, and three-dimensional interference signal intensity is more than the measuring point of preset value, tool
The preset value of body can be the empirically determined value of the engineering staff of profession, be intuitively embodied on signal graph and be shown as fluctuating
Strongly.In other words, signal pickup assembly is mounted on the stronger measuring point of three-dimensional interference signal.
Specifically, in a specific embodiment, the three-dimensional interference signal pulsewidth is in the second measuring point signal
The period of three-dimensional interference signal or wavelength.Moreover, during determining three-dimensional interference signal pulsewidth based on the second measuring point signal, by
The three-dimensional interference signal for including in the second measuring point signal is persistent oscillation, therefore can be made of three-dimensional interference signal
The pulsewidth of one approximate sinusoidal or cosine curve period or wavelength as three-dimensional interference signal, can also be by multiple approximate
Sinusoidal or cosine curve average period or wavelength the pulsewidth as three-dimensional interference signal.
So specifically, when determining the pulsewidth of three-dimensional interference signal, can be formed by reading three-dimensional interference signal
Approximate sinusoidal or cosine curve a period or wavelength or multiple approximate sinusoidal or cosine curve average periods or
Wavelength determines the pulsewidth of three-dimensional interference signal.
The frequency of three-dimensional interference signal asks inverse to obtain according to three-dimensional interference signal pulsewidth；Or it is carried out according to following expression formula
It estimates：
Wherein：νx、Cx、Dx、Respectively wait asking the foundation pile of three-dimensional interference signal frequency concrete Poisson's ratio,
One-dimensional longitudinal wave velocity (m/s), stake diameter (m) and three-dimensional interfering frequency (Hz)；
ν0、C0、D0、It is the concrete Poisson's ratio for having demarcated or having measured foundation pile, one-dimensional longitudinal wave velocity (m/ respectively
S), stake diameter (m) and three-dimensional interfering frequency (Hz)；
The three-dimensional interference signal pulsewidth estimated by foundation pile longitudinal wave velocity divided by the three-dimensional interference signal frequency estimated.
In above step 101 and step 102：
In a specific embodiment, the hammer action is to carry out vertical tap by power hammer or power stick to generate.
In a specific embodiment, when the load pulsewidth or three-dimensional interference signal pulsewidth correspond to the period,
Corresponding to after information processing is wavelength.That is, when the load pulsewidth corresponds to the period with three-dimensional interference signal pulsewidth, list
Position is millisecond (ms), and in information processing unit Low Strain Dynamic Testing of Piles instrument and its processing software, it is mixed due to being multiplied by foundation pile
Solidifying soil longitudinal wave velocity, corresponding to it is wavelength, at this point, the unit conversion of load pulsewidth is rice (m).
In a specific embodiment, first beating point is the solid stake top surface of the building including stake
Any position including top surface central point；Second beating point is the central point on the solid stake top surface of the building.
In a specific embodiment, first signal pickup assembly and/or the second signal harvester are
Probe or sensor, first signal pickup assembly and/or the second signal harvester pass through glue, butter or rubber
The stickums such as mud are pasted onto the solid stake top surface of the building.
In a specific embodiment, first signal pickup assembly and/or the second signal harvester connect
It is connected to information processing unit；Described information processing unit is specially Low Strain Dynamic Testing of Piles instrument.
Specifically, the first signal pickup assembly can be same device with second signal harvester, it is intended merely to distinguish
Different measurement and carried out different names, therefore might not represent and show two devices, naturally it is also possible to be two devices,
Specifically can flexibly it be arranged according to actual measurement situation.
Step 103, selection load pulsewidth：Pulsewidth is selected to be more than the load pulsewidth of three-dimensional interference signal pulsewidth；Or selection makes
Three-dimensional interference signal oscillation characteristics meet pre-determined stability feature, there is not amplitude and frequency in predeterminable area before the signal
More than the load pulsewidth of the three-dimensional interference signal of pre-determined stability characteristic value；Or select pulsewidth and the product of stake top surface wave velocity of wave big
In the load pulsewidth of foundation pile diameter.
Specifically, there are three types of modes for selection load pulsewidth：
Mode 1, selection pulsewidth are more than the load pulsewidth of three-dimensional interference signal pulsewidth, in other words, its inverse are selected to be less than three
Tie up the load pulsewidth of interference signal frequency；
Mode 2, selection make three-dimensional interference signal oscillation characteristics meet pre-determined stability feature, the preset areas before signal
Do not occur the load pulsewidth of amplitude and frequency more than the three-dimensional interference signal of pre-determined stability characteristic value in domain, specifically, selecting
So that three-dimensional interference signal oscillation characteristics are stablized, do not occur apparent amplitude bigger in signal leading portion, frequency is higher three-dimensional dry
Disturb the load pulsewidth of signal.
Specifically, predeterminable area (by width or as unit of the time) before signal, in one embodiment, such as can be with
It is the preceding 4ms (see Fig. 6 and Fig. 7) after sampling starts, is also not limited to this certainly, the environment and survey that it can be based on measurement
The needs of amount it is different and different；Preset invariant feature value refer to then interference signal pulsewidth and frequency in test signal
In remain a certain stationary value, the amplitude of the three-dimensional interference signal of signal leading portion does not increase singularly.For example, frequency values
The discreet value that the three-dimensional interference signal frequency estimation formula proposed in the corresponding present invention obtains, the three-dimensional interference signal of signal leading portion
Amplitude do not increase singularly.
Mode 3, selection pulsewidth are more than the load pulsewidth of foundation pile diameter with the product of stake top surface wave velocity of wave.
Embodiment 2
Fig. 2 is the structural representation that a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles of the present invention determines load pulsewidth
Figure.In the present embodiment, building solid pile is solid circles foundation pile.
Exciting device 200 generates hammer action at the stake top surface arbitrary point of solid pile 100, in building solid pile
At 100 stake top surface, with the adjacent position of beating point, signal pickup assembly 300 is installed as to building solid pile pile body
Measuring point, signal pickup assembly be probe or sensor.Information processing unit 400 is Low Strain Dynamic Testing of Piles instrument.
When exciting device 200 is in the generation beat action of the stake top surface of solid pile 100, pass through sensor and foundation pile
Low strain integrity testing instrument can obtain a velocity test curve.
It is structural schematic diagram shown in Fig. 2 in concrete longitudinal wave velocity 4050m/s, Poisson's ratio also referring to Fig. 3, Fig. 3
0.28, it under the conditions of stake diameter 2.9m, the long 25m of stake, load pulsewidth 1.6ms, is tapped at stake end face center, close to beating point
What is sampled at 0.07R (radius) is approximately sinusoidal incident pulse and the sampling at the sample 0.67R that specification is recommended
Be approximately bell pulse incident pulse.
Fig. 3 shows when pile center taps, and close to the measuring point of beating point, incoming signal is approximate sine curve, lotus
Load pulsewidth is 1.59ms, and only smaller 0.01ms than true load pulsewidth 1.6ms, this difference comes from us can not be by sensor
It is pasted onto beating point center position, and can only be pasted close to beating point.At the sampled point 0.67R as defined in specification, it is originally used for just
The incoming signal of chord curve generates Severe distortion, and the forward direction speed part of distortion accounts for the main body of energy, referred to as bell-shaped pulse, and
The negative sense speed component of distortion is difficult to clearly identify.Engineering circles are generally using this bell-shaped pulse as incoming signal at present.Fig. 3
In, the width of the bell-shaped pulse is 1.08ms, smaller 0.52ms than true load pulsewidth 1.6ms, this is because bell-shaped pulse is only
It is a part for the sinusoidal velocity profile after distortion, i.e., is only a part for incoming signal.So when determining load pulsewidth, I
Need using close to beating point install sensor sample mode.Further, since the forced load that load is additional is tapped, institute
To be tapped in stake top face arbitrary point, incoming signal remains at approximately sinusoidal velocity profile.
Embodiment 3
Fig. 4 is the knot that three-dimensional interference pulsewidth is determined in a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles of the present invention
Structure schematic diagram.In the present embodiment, building solid pile is for real section circle stake.Specially：
Exciting device 200 generates hammer action at the stake top centre of surface point of solid pile 100, in building solid pile
100 stake top surface, the stronger measuring point installation signal pickup assembly 300 of three-dimensional interference signal is as to building solid pile stake
The measuring point of body, signal pickup assembly are probe or sensor.Information processing unit 400 is Low Strain Dynamic Testing of Piles instrument.
When exciting device 200 is when the stake top centre of surface of solid pile 100 generates beat action, by sensor and
Low Strain Dynamic Testing of Piles instrument can obtain a velocity test curve.
Fig. 5 be structural schematic diagram shown in Fig. 4 concrete longitudinal wave velocity 4050m/s, Poisson's ratio 0.28, stake diameter 2.9m,
The long 25m of stake, load pulsewidth 1.6ms under the conditions of no soil layer, are tapped in stake end face center, 0.0R, 0.33R on arbitrary radius,
When being sampled at 0.4R, 0.54R, 0.67R, 0.75R, R, the contrast schematic diagram of calculating speed signal.
Fig. 5 under stake end face center taps embodies following features：
Feature 1：Between incoming signal and pile bottom reflection signal, there are the three-dimensional interference signals of sustained oscillation, and by stake
To outermost measuring point, three-dimensional interference strength is first successively decreased to be incremented by afterwards at midpoint, there is three-dimensional interference smallest point, in this example, due to Poisson
Than being 0.28, three-dimensional interference smallest point is about at 0.53R.
Fig. 5 illustrates that the measuring point on the outside of foundation pile center and foundation pile, their three-dimensional interference signal is stronger, more conducively three
Tie up the accurate reading of interference signal period or wavelength.Therefore, it in step 102 in embodiment 1, proposes in three-dimensional interference signal
Intensity is more than that the measuring point of preset strength value installs second signal harvester.
Specifically, the measuring point that three-dimensional interference signal is more than preset strength value refers to leaving one spacing of the positions 0.67-0.5 υ
From, and three-dimensional interference signal intensity is more than preset value, specific preset value can be that the engineering staff of profession is empirically determined
Value, be intuitively embodied on signal graph that be shown as fluctuation strong.In other words, signal pickup assembly is mounted on three-dimensional interference signal
Stronger measuring point.Feature 2：For single measuring point signal, three-dimensional interference signal is the oscillator signal in the periods such as approximation, i.e. frequency
Rate is stablized.For different measuring points, the period of their three-dimensional interference and frequency approximately equal.In other words, Fig. 5 illustrates, different
The pulsewidth of measuring point signal, three-dimensional interference is consistent.
It is based on this point, in the three-dimensional signal for interfering stronger measuring point to be acquired, the pulsewidth of three-dimensional interference signal
The three-dimensional interference signal pulsewidth of entire foundation pile could be represented.Secondly as three-dimensional interference signal is persistent oscillation, and the period and
Frequency is stable, so, it is just proposed in the step 102 in above-described embodiment 1 when determining the pulsewidth of three-dimensional interference signal,
Approximate sinusoidal or cosine curve the period that can be made up of the three-dimensional interference signal of reading or wavelength or multiple close
As sinusoidal or cosine curve average period or wavelength determine, referring specifically to Fig. 5.Wherein, multiple approximate sines are sought
Cosine curve average period or wavelength can reduce extraneous factor interference and error.
It is structural schematic diagram shown in Fig. 4 in concrete longitudinal wave velocity 4050m/s, Poisson's ratio also referring to Fig. 6, Fig. 6
0.28, stake diameter 2.9m, the long 25m of stake, load pulsewidth are respectively 0.409ms, 0.619ms, 1.239ms, 1.6ms, no soil layer condition
Under, it is tapped in stake end face center, at the 0.67R on arbitrary radius when sampling, the contrast schematic diagram of calculating speed signal.
Fig. 6 shows following characteristics：
Although feature 1, load pulsewidth are different, interference signal feature of each curve in posterior segment is consistent, and the period is equal
For 1.239ms, frequency 809Hz.
Feature 2, when load pulsewidth is more than the period (1.239ms) of the three-dimensional interference of signal back segment, single signal is entire
In sampling process, the pulsewidth of the cycle stability of three-dimensional interference signal, i.e., three-dimensional interference signal is stablized, moreover, at this point, different loads
Under pulsewidth, the three-dimensional interference signal form in each signal is also almost consistent on the whole, only exists the difference of intensity.
These give first selection methods of load pulsewidth：Pulsewidth is selected to be more than the load arteries and veins of three-dimensional interference signal pulsewidth
In other words width selects its inverse less than the load pulsewidth of three-dimensional interference signal frequency.
Feature 3, when load pulsewidth is significantly narrower than period (1.239ms) of the three-dimensional interference signal of signal back segment, such as arteries and veins
Wide 0.409ms and 0.619ms, there are frequency higher, the three-dimensional interference signals of amplitude bigger for signal leading portion at this time.These give lotuses
Carry second selection method of pulsewidth：
Selection is so that three-dimensional interference signal oscillation characteristics meet pre-determined stability feature, before the signal in predeterminable area not
There is the load pulsewidth of amplitude and frequency more than the three-dimensional interference signal of pre-determined stability characteristic value, specifically, i.e. selection is so that three
It ties up interference signal oscillation characteristics to stablize, does not occur apparent amplitude bigger, the lotus of the higher interference signal of frequency in signal leading portion
Carry pulsewidth.
It is structural schematic diagram shown in Fig. 4 in concrete longitudinal wave velocity 4050m/s, Poisson's ratio also referring to Fig. 7, Fig. 7
0.28, stake diameter 2.9m, the long 25m of stake, load pulsewidth 0.619ms under the conditions of no soil layer, are tapped, arbitrary radius in stake end face center
On 0.39R, 0.53R, 0.67R at sample when, the contrast schematic diagram of calculating speed signal.
When Fig. 7 shows to tap pulsewidth 0.619ms, first, at three-dimensional interference smallest point 0.53R, in the back segment of signal,
Interference signal intensity is approximately zero, but in signal leading portion, and stake top different measuring points all have significant interference strength bigger, and frequency is more
High interference signal.They can not be avoided by the selection of measuring point, i.e. the leading portion in signal sampling, three-dimensional interference smallest point
Sampling method fails, in other words, existing specification method of sampling failure.Secondly, this being present in signal leading portion, interference strength is more
Greatly, the higher interference signal of frequency, they will be considered as superficial part major defect signal, be not used to foundation pile judge.Above-mentioned phenomenon
It is the basic point of departure of second selection method of load pulsewidth in the present invention.
Also referring to Fig. 8 A-8D, Fig. 8 A- Fig. 8 D are concrete longitudinal wave velocity 4050m/s, Poisson's ratio 0.28, stake diameter
When 2.9m, the long 25m of stake, load pulsewidth are respectively 0.409ms, 0.619ms, 1.239ms, 1.6ms, under the conditions of no soil layer, in stake
End face center taps, the middle point moment of load action and finish time, by the vertical section of stake axis in stake top near zone
Sum velocity vector cloud atlas contrast schematic diagram.
Fig. 8 A-8D are shown, within the load action period, the sum velocity vector field of stake top region unilateral side, is by one in section
What a or multiple speed spirals for not stopping to rotate and move were constituted, and the movement speed of speed spiral center is approximately surface
Wave velocity of wave.In conjunction with simultaneously comparison diagram 8A-8D and Fig. 6 it is found that signal leading portion does not occur amplitude bigger, the higher interference signal of frequency
Always a speed spiral is only existed when load pulsewidth, within the scope of stake top cross sectional radius, so, we have proposed load pulsewidths
Third selection method, the half of load pulsewidth and the product of surface wave velocity of wave are more than the radius of foundation pile.
The load pulsewidth selection method of a kind of Low Strain Dynamic Testing of Piles of the present invention, by the solid stake top table of building
Beating point is arranged in face, and signal pickup assembly is installed close to beating point, obtains the load pulsewidth that accurate pile monkey taps concrete, this
It lays a good foundation for the selection and making of pile monkey.Secondly, method and the three-dimensional interference of estimation of the three-dimensional interference pulsewidth of test are given
The expression formula of signal frequency, furthermore, give the selection method of load pulsewidth.When load pulsewidth meets load proposed by the present invention
When the selection method of pulsewidth, the oscillating characteristic of three-dimensional interference signal is stablized, and does not occur amplitude bigger in the leading portion of signal, frequency is more
High three-dimensional interference signal.There is this amplitude bigger due to working as signal leading portion, when the higher interference signal of frequency, they can not
It is eliminated by selecting sampling point position, that is, in this period, the three-dimensional of existence anduniquess does not interfere most in stake top surface radius
Dot, so in this period, the basic ideas of existing low strain integrity testing method sample this side at three-dimensional interference smallest point
Method fails.In other words, the present invention can solve the problems, such as how to select corresponding pile monkey (as stake diameter is different) for different foundation piles.
Furthermore under conditions of meeting load pulsewidth selection method proposed by the present invention, using relatively narrow load pulsewidth, it can ensure
Under the premise of three-dimensional interference smallest point sampling method does not fail, improves and ensure the resolution ratio of defect, that is, improve test signal
Quality, to help more accurately to judge the integrality of building solid pile pile body.
It will be appreciated by those skilled in the art that the accompanying drawings are only schematic diagrams of a preferred implementation scenario, module in attached drawing or
Flow is not necessarily implemented necessary to the present invention.
It will be appreciated by those skilled in the art that the module in device in implement scene can be described according to implement scene into
Row is distributed in the device of implement scene, can also be carried out respective change and is located at the one or more dresses for being different from this implement scene
In setting.The module of above-mentioned implement scene can be merged into a module, can also be further split into multiple submodule.
Aforementioned present invention serial number is for illustration only, does not represent the quality of implement scene.
Disclosed above is only several specific implementation scenes of the present invention, and still, the present invention is not limited to this, Ren Heben
What the technical staff in field can think variation should all fall into protection scope of the present invention.
Claims (6)
1. a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles, which is characterized in that it is solid that this method is applied to building
Stake pile body, the building solid pile pile body is specially building solid circles foundation pile；This method comprises the following steps：
Step A, the determination of load pulsewidth：The first beating point is set on the solid stake top surface of building, and is struck described first
First signal pickup assembly is installed, when receiving the hammer action in first beating point in preset range centered on hitting a little
When, the first measuring point signal from first signal pickup assembly is obtained, and load is determined by the first measuring point signal
Pulsewidth；First beating point is the arbitrary position including stake top centre of surface point on the solid stake top surface of the building
It sets；The load pulsewidth be the first measuring point signal in be approximately sinusoidal incoming signal period or wavelength；It is described
It refer to the measuring point close to beating point in preset range centered on first beating point；
Step B, the determination of three-dimensional interference signal pulsewidth：In the solid stake top centre of surface of building, the second beating point is set,
Three-dimensional interference signal intensity is more than that the measuring point of preset strength value installs second signal harvester, when receiving in the second beating point
Hammer action when, obtain the second measuring point signal from second signal harvester, and based on the second measuring point signal it is true
Fixed three-dimensional interference signal pulsewidth；Second beating point is the central point on the solid stake top surface of the building；The three-dimensional
Interference signal pulsewidth is the period of three-dimensional interference signal or wavelength in the second measuring point signal；
Step C, load pulsewidth is selected：Pulsewidth is selected to be more than the load pulsewidth of three-dimensional interference signal pulsewidth；Or selection is so that three-dimensional
Interference signal oscillation characteristics meet pre-determined stability feature, and it is more than pre- not occur amplitude and frequency in predeterminable area before the signal
If the load pulsewidth of the three-dimensional interference signal of invariant feature value；Or selection pulsewidth and the product of stake top surface wave velocity of wave are more than foundation pile
The load pulsewidth of diameter.
2. a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles according to claim 1, which is characterized in that described
Hammer action is to carry out vertical tap by power hammer or power stick to generate.
3. a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles according to claim 1, which is characterized in that described
First signal pickup assembly and/or the second signal harvester are probe or sensor, first signal pickup assembly
And/or by stickums such as glue, butter or plasticine to be pasted onto the building solid for the second signal harvester
Stake top surface.
4. a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles according to claim 1, which is characterized in that described
First signal pickup assembly and/or the second signal harvester are connected with information processing unit；Described information processing unit
Specially Low Strain Dynamic Testing of Piles instrument.
5. a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles according to claim 1, which is characterized in that work as institute
It states load pulsewidth or three-dimensional interference signal pulsewidth corresponds to the period, wavelength is corresponded to after information processing.
6. a kind of load pulsewidth selection method of Low Strain Dynamic Testing of Piles according to claim 1, which is characterized in that three-dimensional
The frequency of interference signal asks inverse to obtain according to three-dimensional interference signal pulsewidth；Or it is estimated according to following expression formula：
Wherein：νx、Cx、Dx、It respectively waits asking the concrete Poisson's ratio of the foundation pile of three-dimensional interference signal frequency, one-dimensional longitudinal wave
Velocity of wave (m/s), stake diameter (m) and three-dimensional interfering frequency (Hz)；
ν0、C0、D0、It is the concrete Poisson's ratio for having demarcated or having measured foundation pile, one-dimensional longitudinal wave velocity (m/s), stake diameter respectively
(m) and three-dimensional interfering frequency (Hz)；
The three-dimensional interference signal pulsewidth estimated by foundation pile longitudinal wave velocity divided by the three-dimensional interference signal frequency estimated.
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