CN103255785A - Technology for performing foundation pile quality detection and geology survey by adopting single tube longitudinal wave method - Google Patents

Abstract

The invention relates to a technology for performing foundation pile quality detection and geology survey by adopting a single tube longitudinal wave method. The technology is relevant to comprehensive testing of the actual using effect of a foundation pile and is characterized in that longitudinal wave transmitting downwards along a pile body is generated by knocking the top surface of the foundation pile, the longitudinal wave velocity and pile length of the foundation pile can be accurately measured by detecting the time difference of arrival of the longitudinal wave in a sounding pipe, and the quality of pile body concrete can be judged; actual measurement on the time difference of arrival of the longitudinal wave which is transmitted from the pile side soil along the knocked pile body can be conducted in adjacent pipelines or geological bore holes, and the length of the foundation pile, the pile body quality and the chambering degree can be measured; and the wave length of a geological soil layer can be measured, the condition of the geological soil layer around the pile can be judged, and the rock-inlet condition of the foundation pile can be analyzed. By means of the technology for performing foundation pile quality detection and geology survey by adopting the single tube longitudinal wave method, a signal processor can be configured externally or inserted in on the basis of the existing low-strain ultrasonic detection devices and the like, the technology can achieve foundation pile quality nondestructive testing and geology survey, is an economic and ready-made pile foundation nondestructive testing auxiliary validation method and can remarkably improve accuracy and service level of pile foundation quality decision.

Description

Adopt the single tube normal beam technique to carry out the technology of pile quality detection and geology detecting

Affiliated technical field

The present invention relates to the technology of the nondestructive testing of foundation pile construction quality and geology detecting.

Background technology

Under existing dynamic pile test condition, also there are many uncertainties in the detection of pile foundation construction quality, has influence on the correct judgement of pile foundation construction quality:

1. though the dynamic test for pile foundation method can be sensed the information of all soil of stake and stake bed rock layer, owing to can not quantize the corresponding specific targets of its geological condition, can not confirm the supporting capacity of pile foundation.

2. can not accurately measure the foundation pile velocity of wave, so that can not judge accurately that stake is long and estimate the integral level of foundation pile concrete quality.The difficulty that also exists some to use in the method that pile crown adopts dual sensor to demarcate foundation pile concrete velocity of wave, as: (1). the situation that exposes pile crown seldom exists; (2). near the concrete quality the in situ pile pile crown is relatively poor relatively, can not represent the average quality situation of whole stake etc.

3. all soft or hard soil layers of the castinplace pile that the pile body cross section is changeable and amplitude of variation is bigger, and stake change tangible geological conditions, all can cause testing result inaccurate, need to adopt other householder method checking.

4. for the quality examination of the pre cast pile of super long pile, manually digging hole filling pile, multi-segmental etc., often because of the reflected signal at the bottom of can't detecting, can only rely on the testing staff in conjunction with the experience synthetic determination, or adopt other method further to detect.

5. for the quality examination of socketed pile and bearing pile, the reflection wave signal that homophase at the bottom of stake, occurs, or time-domain curve is not seen into the rock signal and when not having pile bottom reflection ripple signal, also need adopt veritifications such as the method for loosing core to the judgement of stake base concrete quality and pile bottom force holding layer situation.

Existing pile foundation transmission ultrasonic wave method detection technique has its limitation, and existence can not be implemented effectively to detect and the mistake check weighing such as declares at situation:

1. pile foundation transmission ultrasonic wave method can only reflect the sound detecting pipe scope with interior pile body concrete quality, can not reflect all soil of stake and bearing course at pile end situation.

2. because displacement appears in sound detecting pipe easily that bury underground, making range finding become uncertain important parameter, so be difficult to obtain accurately and can represent the average velocity of wave of putting in order pile driving construction quality level; At the bottom of stake section also normal appearance depart from the maximum value or minimum value of physical significance fully, cause and pass judgment on difficulty.

3. when little defectives such as the local folder of sound detecting pipe periphery appearance mud, easily be mistaken for great quality problems such as serious undergauge, broken pile.

When the corrosion of sound detecting pipe inwall, outer wall mud skin is thicker or sound detecting pipe and concrete break away from when splitting, ultrasonic wave can't transmission, these situations or cause mistake to survey erroneous judgement.

5. when sound detecting pipe distortion, when stopping up, can not effectively detect and judge the processing of to loose core pile body or a stake end.

Under existing pile foundation construction quality Dynamic Non-Destruction Measurement condition, in the time can't detecting judgement or the quality query occur, generally adopt the method verification of loosing core, but it is higher that the method for loosing core is tested a cost, consuming time longer, for long stake loose core also be difficult to be extracted at the bottom of, the situation of bearing course at pile end also can only be provided simultaneously, can not resolve bearing capacity of pile foundation, therefore existing pile foundation construction quality detection technology can't satisfy the demand of reality fully comprehensively.

Summary of the invention

Purpose of the present invention; be to wish to improve on the basis of existing detecting instrument equipment and innovate; and the condition of utilizing engineering site to provide; the research invention is a kind of not only can carry out the pile quality nondestructive testing; and the new technology that can also survey stake week geology soil layer; guarantee construction quality and the bearing capacity of foundation pile, become ready-made, accurately, the aided verification method of economic pile foundation Dynamic Non-Destruction Measurement, improve accuracy and service level that the pile foundation nondestructive testing is judged.

The technical solution adopted for the present invention to solve the technical problems is: adopt the single tube normal beam technique to carry out the technology of pile quality detection and geology detecting, it is characterized in that checked object is the steel concrete foundation pile, buried sound detecting pipe or core-drawing hole underground at the foundation pile pile body, its test macro comprises: power hammer (rod), sensor, wave detector, single tube normal beam technique signal processor and Acquisition Instrument.Power hammer (rod) knocks exciting at the foundation pile end face and produces a compressional wave of propagating along pile body downwards, by on the end face of foundation pile or at the sensor that power hammer (rod) is installed, detecting knocking, in sound detecting pipe or core-drawing hole, detect the transmitting signal that knocks compressional wave by wave detector, measure wave detector and lay the degree of depth that enters below the foundation pile end face, sensor and wave detector are connected respectively to the input of single tube normal beam technique signal processor, the major function of single tube normal beam technique signal processor be with the detected knocking of sensor be processed into one with knock synchronous single pulse signal of exciting moment, and synchronization pulse is added in the signal that wave detector detects, signal after will handling is again delivered to Acquisition Instrument, carry out data acquisition by Acquisition Instrument, storage and initial analysis, measure the propagation time difference of compressional wave and calculate the longitudinal wave velocity of foundation pile, the length of the size by analyzing longitudinal wave velocity and the relation judgement foundation pile of propagation time difference and the detection degree of depth, pile body concrete quality.

The single pile single tube detects to such an extent that the one dimension rod longitudinal wave velocity is that the average velocity of wave to pile cutoff between test point is pushed up in stake, when the pile body concrete quality uniformity, equates and equal this average velocity of wave at all detected velocities of wave in degree of depth place.When the material that adopts when concrete is identical with match ratio, can estimate the quality level of whole pile concrete in conjunction with the age of concrete, the representative velocity of wave that records can be used as the representative velocity of wave of low strain testing, and it is long to be used for accurately estimating stake.

Foundation pile h_iThe longitudinal wave propagation speed of place's actual measurement is that the average velocity of wave to pile cutoff between test point is pushed up in stake

c_i＝h_i/t_i

H in the formula_iFor foundation pile end face to wave detector is surveyed distance between central point

t_iBe h_iLocate the descending wave propagation time difference

Homogeneous concrete t_iWith degree of depth h_iBe the linear changing relation, slope of a curve is a constant.When diminishing, slope represents that velocity of wave reduces, and is reflected as t_i-h_iOccur flex point on the curve, there is mass defect in the interval pile concrete that flex point occurs; At t_i-h_iOn the curve, t_iHave additive effect to represent the defective that full section character appears in pile foundation, not having additive effect is local defect.

Can utilize amplitude change and the wave distortion of actual measurement compressional wave to come the long and pile body concrete quality of analysis-by-synthesis stake, according to foundation pile one dimension elastic rod theory, also the superposeed reflection (upgoing wave) at interfaces such as the pile foundation abrupt change of cross section, the stake end and stake side formation variations of the descending ripple of actual measurement changes measured waveform.The reflection that the energy of ripple can change because of the pile body wave impedance and stake side soil absorb and reduce, also can be because of being absorbed by pile defect or shielding and reduce.

By at h_iAnd h_I+iMeasure the difference t time of advent of descending ripple in the detection signal at place respectively_iAnd t_I+1The difference t time of advent with the pile bottom reflection ripple_HAnd t_H+1, calculate that the actual stake of foundation pile is long

L＝h_i+Δh/(Δt_i+1-Δt_i)*Δt_i

Or L=h_I+1+ Δ h/ (Δ t_I+1-Δ t_i) * Δ t_I+1

Δ t in the formula_i=t_H-t_i

Δt_i+1＝t_H+1-t_i+1

Δ h=h_I+1-h_iBe h_iWith h_I+1The discrepancy in elevation

t_iAnd t_I+1For at h_iAnd h_I+1The descending wave propagation time difference in place's detection signal

t_HAnd t_H+1For at h_iAnd h_I+1The propagation time difference of back wave at the bottom of place's detection signal king-pile

The going into the rock signal and may arrive in advance than pile bottom reflection signal of foundation pile utilizes foundation pile length reality that following formula tries to achieve to push up the degree of depth to scar for stake, thus can utilize that its relation judges foundation pile effectively go into the rock degree of depth

H＝h_man+a-L′

H in the formula_ManBe the darkest detection degree of depth

A is that the darkest detection degree of depth is to the stake distance at the end

L ' is that the degree of depth to scar is pushed up in stake

Test shows since the sound detecting pipe tube wall is thin, rigidity is little and with pile concrete bonding, can constitute one and common vibration with pile concrete, so in sound detecting pipe, measure the longitudinal wave velocity of foundation pile, can not be subjected to the influence of steel pipe material.

The invention is characterized in the adjacent stake sound detecting pipe of adjacent foundation pile or adjacent stake core-drawing hole to detect by wave detector and knock compressional wave along the foundation pile pile body and the signal of propagating from stake side geology soil layer downwards, the time of advent of measuring compressional wave is poor, measure wave detector and lay the degree of depth that enters below the foundation pile end face, judge length, pile body concrete quality and the reaming degree of foundation pile by the relation of analyzing propagation time difference and the detection degree of depth; Oneself knows the pile concrete velocity of wave, concern according to time-histories and ask the longitudinal wave velocity of calculating the geology soil layer, and the situation of all geology soil layers of differentiation stake is gone into the rock situation with the analysis foundation pile.

Detect by the longitudinal wave propagation time difference t of exciting at adjacent foundation pile_i, formed by exciting stake and stake side geology soil layer two time-histories partly: when pile foundation is complete, only reflect the variation of geology soil layer; When geology soil layer homogeneous, only reflect the variation of tested stake; When two pilespacings more are the variation that has reflected tested stake when nearer; When two pilespacings are away from, it more is the variation that has reflected the geology soil layer.When being used for differentiating pile foundation quality, should improve understanding and understanding to the situations such as geology of one's respective area at several piles of the many detections of the same area.The length of adjacent stake should can be passed through t more than or equal to the length of tested foundation pile when the judgement stake was long_i-h_iA knee of curve method judgement stake position, the end comes the verification stake long; Also can utilize known S, h_i, c_i, v_iWith t_iThe relational checking stake long

h＝(t_i-S/v_i)*c_i

S is the distance of foundation pile and adjacent stake in the formula

v_iVelocity of wave for stratum at the bottom of this stake

c_iVelocity of wave for this pile concrete

t_iFor corresponding to the stake bottom descending wave propagation time difference

At the pile cutoff that reaming may occur, work as t_i-h_iThe curve indent, t_iWhen obviously reducing, can be judged to pile body and reaming occur, the value added of its reaming

L＝(v_im*h_i-t_i*c_i*v_im)/(c_i-v_im)

C in the formula_iVelocity of wave for pile concrete

v_ImBe h_iThe normal velocity of wave on stratum, place

t_iBe the descending wave propagation of the reaming place time difference

For accurately measuring the velocity of wave of geology soil layer, should choose two full piles, and two pilespacings are away from, the longitudinal wave velocity of geology soil layer

v_i＝S/(t_i-h_i/c_i)

In the formula: v_iLongitudinal wave velocity for the geology soil layer

S is the distance of foundation pile and adjacent foundation pile

c_iAverage longitudinal wave velocity for foundation pile

Consider when compressional wave is walked the fastest shortcut, then the longitudinal wave velocity v of geology soil layer correction_Ii

$v_{\mathrm{ii}}=\sqrt{\frac{{\mathrm{<figure-callout\; label="s"\; filenames="HSA00000670380500061.png"\; state="\{\{state\}\}">s</figure-callout>}}^2*{c_i}^2}{{{\mathrm{<figure-callout\; label="c\; i"\; filenames="HSA00000670380500061.png"\; state="\{\{state\}\}">c</figure-callout>}}_i}^2*{(t_i-\frac{h_i}{c_i})}^2+{\mathrm{<figure-callout\; label="s"\; filenames="HSA00000670380500061.png"\; state="\{\{state\}\}">s</figure-callout>}}^2}}$

The of the present invention detection by wave detector in geotechnical boring knocked compressional wave along the foundation pile pile body and the signal of propagating from stake side geology soil layer downwards, the time of advent of measuring compressional wave is poor, measure wave detector and lay the degree of depth that enters below the foundation pile end face, ask the longitudinal wave velocity of calculating the geology soil layer according to the physical relation of time-histories, and the situation of all geology soil layers of judgement stake, analyze foundation pile and go into the rock situation.

The longitudinal wave velocity of geology soil layer

v_i＝S/(t_i-h_i/c_i)

V in the formula_iLongitudinal wave velocity for the geology soil layer

S is the distance of foundation pile and geotechnical boring

c_iAverage longitudinal wave velocity for foundation pile

In the geology hole, detect the soil layer compressional wave, can eliminate in the adjacent stake single tube normal beam technique when two approaching and hammer vibration energy when big, resonate because adjacent stake exists, the phenomenon that the particle of a neighbour bottom is vibrated in advance.Should select the full pile of known quality for use and adopt big exciting force, detect at a distance in distance, improve the accuracy that geology soil layer velocity of wave detects; And when surveying the unfavorable geology structures such as soil cave, solution cavity of stake side, then should adopt short range finding.

The invention is characterized in that a kind of single tube normal beam technique signal processor is by voltage amplifier I, voltage amplifier II, voltage comparator circuit, the monostable trigger circuit, voltage adder circuit and power circuit are formed, the output of voltage amplifier I is connected to the input of voltage comparator circuit, the output of voltage comparator circuit is connected to the trigger end of monostable trigger circuit, the output of monostable trigger circuit and voltage amplifier II is connected respectively to two inputs of voltage adder circuit, by the voltage signal of the synthetic longitudinal elastic wave that knocks the exciting synchronization pulse of having superposeed of voltage adder circuit.Automatically trigger and gather from the Acquisition Instrument that triggers function by having signal, also the synchronization pulse of single tube normal beam technique signal processor can be directly connected to the external trigger input interface of Acquisition Instrument, the control Acquisition Instrument is gathered the signal of wave detector synchronously.

The invention is characterized in that single tube normal beam technique signal processor has increased wireless transmitter module in the rearmost end of circuit, in Acquisition Instrument inside or the outside corresponding wireless receiving module has been installed, constitute wireless connection system.The circuit of single tube normal beam technique signal processor can be directly embedded in the existing Acquisition Instrument, constitute a kind of intelligent acquisition instrument with single tube normal beam technique measuring ability.The Acquisition Instrument of above-mentioned indication comprises: dynamic testing of pile instrument, nonmetal ultrasonic detector, ultrasonic wave follow surveys instrument, high strain detector, engineering dynamic tester and seismic detector etc.The wave detector that the present invention adopts comprises: broadband ultrasonic wave transducer, hydrophone, three-component geophone etc.Existing three-component geophone diameter is bigger, is not suitable for being applied in the sound detecting pipe and detects, and should adopt the less broadband ultrasonic wave transducer of diameter, and is not only economical, and one-object-many-purposes, easy to carry.

The invention is characterized in wave detector and wave detector II have been installed in sound detecting pipe or core-drawing hole simultaneously, the constant distance of two wave detectors of testing process, by measuring the time difference of same exciting ripple, measure the concrete velocity of wave of corresponding pile cutoff between two wave detectors, to improve the sensitivity that the pile body local defect is judged.

The invention is characterized in and the invention has the beneficial effects as follows, according to foundation pile one dimension rod elastic oscillation theory, explicit physical meaning, single tube normal beam technique signal processor by invention, can directly adopt intelligent equipments such as existing dynamic testing of pile instrument and supersonic reflectoscope, under existing engineering-environment condition, realize that quickly and accurately a kind of new foundation pile can't harm quality examination.Because sensor very closely can be placed in pile crown beating point next door, this law can accurately be measured the longitudinal wave velocity of foundation pile.According to homogeneous concrete t_iWith degree of depth h_iBe the basic law of linear change and the additive effect of time-histories, can accurately differentiate position and the order of severity of defective.Can judge pile bottom reflection signal and go into the rock signal, it is long and effectively go into the rock degree of depth accurately to calculate the actual stake of foundation pile.Utilize sound detecting pipe on the adjacent foundation pile, core-drawing hole and a stake side geotechnical boring to carry out the pile foundation nondestructive testing, can further expand to the foundation pile of buried pipeline is not carried out quality examination, be applied to the nondestructive testing of existing building foundation pile simultaneously.When the sound detecting pipe obstruction can not realize detecting fully or adopt dynamic measurement of pile abnormality inconvenience judgement to occur, the present invention can be used as the aided verification method of pile foundation nondestructive testing, can significantly improve accuracy and service level that pile foundation quality is judged.Utilize sound detecting pipe, core-drawing hole and stake side geotechnical boring on the adjacent foundation pile to carry out geology detecting, can measure velocity of wave, the situation of all geology soil layers of judgement stake, the analysis foundation pile of geology soil layer and go into the rock situation, adopting the punching hammer of standard penetration test to knock soil sampler with geology detecting cross hole method wave velocity testing technology compares as vibration source, the present invention with the engineering stake as feeler lever, adopt heavier power rod exciting on the stake top, the vibration wave that produces downwards and propagate to the stake side periphery, have fast, economical, and can carry out the advantage of wave velocity testing to the solid rock stratum; Than the single hole wave velocity testing method that excites on the face of land, the present invention can better get rid of soil layer to the influence of test result, utilizes existing pile foundation to carry out comprehensive geology detecting, can be detailed and the geology and geomorphology of analysis stake position economically.Single tube normal beam technique signal processor of the present invention, voltage comparator circuit, monostable trigger circuit and three functional circuits of add circuit have mainly been adopted, have and judge that quick, reliable, the little power consumption of function-stable reaches the advantage that does not take the Acquisition Instrument operation program, both can be designed to individual devices, offering the numerous intelligent Acquisition Instrument with signal triggering function uses, also the monostable trigger circuit can be directly connected to the Acquisition Instrument with external trigger function, control Acquisition Instrument synchronous working increases main frame and can match scope.Increase wireless transmitter module in single tube normal beam technique signal processor rear end or directly the circuit of single tube normal beam technique signal processor is embedded in the main frame, have simplified apparatus, the convenient detection, and constitute the integrated new equipment with single tube normal beam technique measuring ability.Wave detector adopts less broadband ultrasonic wave transducer and the hydrophone of diameter, not only is applicable in sound detecting pipe and detects one-object-many-purposes, easy to carry, testing process also needn't adopt the rubber pocket inflation to be close to tube wall, obviously optimizes trace routine, and has saved testing cost.Adopt two wave detectors to detect in the testing process simultaneously, can improve the sensitivity that the pile body local defect is judged.

Description of drawings

Below in conjunction with drawings and Examples structure of the present invention and implementation method are further described.

Fig. 1 is the principle schematic that single pile single tube normal beam technique detects.

Fig. 2 is the principle schematic that adjacent stake single tube normal beam technique detects.

Fig. 3 is the principle schematic that adjacent hole single tube normal beam technique detects.

Fig. 4 is a kind of circuit theory and system's connection diagram of single tube normal beam technique signal processor.

Fig. 5 is the circuit theory schematic diagram that adopts a kind of single tube normal beam technique signal processor of wireless transmit.

Fig. 6 is pile concrete defective and t_i-h_iThe schematic diagram of curved line relation

Fig. 7 is the oscillogram of certain stake (the long 29.1m of stake) 22m place actual measurement in sound detecting pipe

Fig. 8 is the oscillogram of certain stake (the long 29.1m of stake) 25m place actual measurement in sound detecting pipe

Fig. 9 is the oscillogram of certain stake (the long 29.1m of stake) 29m place actual measurement in sound detecting pipe

Figure 10 is certain t that utilizes single pile single tube normal beam technique to detect_i-h_iDrawing

Figure 11 is certain transmission ultrasonic wave method testing result

Figure 12 is the t that surveys in the adjacent stake sound detecting pipe of 3.9m_i-h_iCorrelation diagram

Figure 13 is the t that surveys in the adjacent stake sound detecting pipe of 9.8m_i-h_iThe stratum V-h distribution map of correlation diagram and calculating

Figure 14 is the principle schematic that adopts the single pile single tube normal beam technique detection of wireless receiving and dispatching working method.

Figure 15 adopts the diplopore method to detect the principle schematic of stratum velocity of wave

Figure 16 is the principle schematic that single pile single tube normal beam technique adopts two wave detectors to detect

Among the figure: 1. foundation pile, 2. sound detecting pipe, 3. core-drawing hole, 4. power is hammered (rod) into shape, 5. sensor, 6. wave detector, 7. single tube normal beam technique signal processor, 8. Acquisition Instrument, 9. adjacent foundation pile, a 10. adjacent sound detecting pipe, 11. an adjacent core-drawinghole 12. geology soil layers, 13. wireless receiving module, 14. wave detector II, 15. geotechnical borings, 7-1. voltage amplifier I, 7-2. voltage amplifier II, 7-3. voltage comparator circuit, 7-4. monostable trigger circuit, 7-5. voltage adder circuit, 7-6. power circuit, the 7-7. wireless transmitter module.

The specific embodiment

Embodiment 1

Adopt single pile single tube normal beam technique to detect the pile concrete construction quality

Adopt single pile single tube normal beam technique to detect the pile concrete construction quality as shown in Figure 1, whereinAcquisition Instrument 8 uses the dynamic testing of pile instrument, the fundamental diagram of single tube normal beamtechnique signal processor 7 and connection are as shown in Figure 4, adopt iron hammer asexciting hammer 4, degree of will speed upsensor 5 is installed in an end face exciting point next door,wave detector 6 adopts the highly sensitive ultrasonic transducer of RS-YH45III wideband, and probe diameter Φ 26mm utilizessound detecting pipe 2 to be sense channel.Be depicted as certain respectively at the capable figure of ripple of 22m, 25m and 29m place actual measurement as accompanying drawing 7, accompanying drawing 8 and accompanying drawing 9, what superpose in the signal of the capable figure of ripple knocks synchronizing signal, the descending ripple and the upgoing wave that comprise accumulation signal, descending ripple is direct wave, the stake end and the back wave of going into the rock place are upgoing wave, and the wave amplitude of pile bottom reflection ripple is obviously higher as seen from the figure.

It is as follows to detect the data analysis computational methods:

1. foundation pile h_iThe descending wave propagation time of place's actual measurement is poor

t_i＝t_h-t₀

T in the formula_hBe h_iThe moment of place's actual measurement

t₀For knocking the moment of exciting

2. foundation pile h_iThe longitudinal wave propagation speed of place's actual measurement is that the average velocity of wave to pile cutoff between test point is pushed up in stake

c_i＝h_i/t_i

H in the formula_iFor foundation pile end face to wave detector is surveyed the degree of depth between central point

3. foundation pile h_iThe slope of place's actual measurement

k＝(h_i+1-h_i)/(t_i+1-t_i)

H in the formula_I+1Be h_iThe next test point degree of depth

t_I+1For at h_I+1The time difference of place's actual measurement

Can adopt the slope criterion to improve the susceptibility of judging defective

K＝＝(h_i+1-h_i)²/(t_i+1-t_i)

4. the average velocity of wave c of pile foundation concrete_iDetermine

4-1 when the pile body concrete quality uniformity, all detected c in degree of depth place_iEquate and equal this average velocity of wave.For reducing the influence that embedding rock back wave stack back is differentiated the pile bottom reflection ripple, should get the signal before foundation pile is gone into rock for socketed pile.

When 4-2 open defect occurs when pile body, should get rid of the unusual velocity of wave of fault location, calculate its velocity of wave average.

4-3 chooses the average velocity of wave c that is no less than 5 piles_mCalculating velocity of wave as the dynamic measurement of pile of this project.

5. the actual stake of foundation pile is long

L＝h_i+Δh/(Δt_i+1-Δt_i)*Δt_i

Or L=h_I+1+ Δ h/ (Δ t_I+1-Δ t_i) * Δ t_I+1

Δ t in the formula_i=t_H-t_i

Δt_i+1＝t_H+1-t_i+1

Δh＝h_i+1-h_i

6. the rock degree of depth of going into of foundation pile is

H＝h_man+a-L′

H in the formula_ManBe the darkest detection degree of depth

A is that the darkest detection degree of depth is to a stake end distance

L ' is that the degree of depth to scar is pushed up in stake

Accompanying drawing 6 is pile concrete defective and t_i-h_iThe schematic diagram of curved line relation:

1. as the A curve among the figure, when the pile body concrete quality uniformity, t_i-h_iBe a straight line, slope is a constant.

2. as a of the B curve among the figure₁To a₂The interval, when wave detector passes through the pile body local defect, t_iIncrement make t_i-h_iCurve is the evagination phenomenon and progressively recovers, and interval slope is a variable.

3. as the b of the B curve among the figure₃To b₄And c₅To c₆The interval, when the defective of section character appears in pile body, t_iIncrement be additive effect, interval slope reduces, and the more serious slope of the degree of defective is more low.

4. as a of the B curve among the figure₂To b₃And b₄To c₅The interval, when pile body concrete quality recovers normal level, t_iPressing normal value increases, and slope also returns to normal level.

Receive waveform and also be one of foundation that quality judges, the reflection that the energy of descending ripple can change because of the pile body wave impedance and the absorption of stake side soil reduce, also can be because of being reduced by the absorption of pile defect or shielding.Near the pile foundation abrupt change of cross section, the stake end and stake side formation variations section, also the superposeed upgoing wave of boundary reflection of the downward traveling waveform of actual measurement changes measured waveform.

Adopt single pile single tube normal beam technique to detect the principle of judging the pile concrete construction quality:

1. survey velocity of wave in normal range (NR), t_i-h_iBe a straight line, slope is a constant, can be judged to the pile body concrete quality uniformity, is full pile.

2. the actual measurement velocity of wave is normal substantially, t_i-h_iThe local evagination of curve also progressively recovers t_i-h_iCurve totally is a straight line, and the below receives the wave-wave width of cloth and obviously do not reduce, and can be judged to pile body and local light defects occur.

3. the actual measurement velocity of wave is normal substantially, t_i-h_iThe local obviously evagination of curve, t_i-h_iSome additive effects appear in curve, and the below receives the wave-wave width of cloth and obviously reduces, and can be judged to pile body and local major defect occur.

4. the actual measurement velocity of wave is normal substantially, t_i-h_iAdditive effect appears in curve, and slope slightly reduces, below t_i-h_iSlope of a curve is constant, can be judged to the light defects that section character appears in pile body.

5. the actual measurement velocity of wave is normal substantially, t_i-h_iPhenomenon appears obviously adding up in curve, and slope reduces, and it is obvious that the below receives wave attenuation, can be judged to the major defect that section character appears in pile body.

6. the actual measurement velocity of wave is on the low side, can be judged to pile body concrete quality and have query.

The strength grade of concrete of certain bridge foundation pile is C30, the moving survey velocity of wave of the left 18-1 stake of bridge, left 18-2 stake, left 18-3 stake and right 18-1 stake, right 18-2 stake is 4283m/s, 4302m/s, 4302m/s, 4302m/s, 4214m/s, and the velocity of wave of calibration reason condition is obviously higher.Adopt single pile single tube normal beam technique to demarcate, the velocity of wave of surveying left 18-2 stake, right 18-stake and right 18-3 stake be respectively 4282m/s, 4211m/s and 4244m/s close with the velocity of wave that dynamic measurement of pile detects, prove long errorless, the verification of must not loosing core.

Accompanying drawing 10 is t that certain engineering pile foundation utilizes the actual measurement of single pile single tube normal beam technique_i-h_iDrawing, 33m below t as seen from the figure_i-h_iThe curve phenomenon that occurs obviously adding up, slope reduces, and has major defect at the bottom of being judged to, this transmission ultrasonic wave method testing result as shown in Figure 11, both testing result unanimities.

Accompanying drawing 7 is certain the capable figure of ripple that surveys at the 22m place, its Δ t_i=t_H-t_i=11.97-5.34=6.63ms, accompanying drawing 8 are that same stake is at the capable figure of ripple of 25m place actual measurement, Δ t_I+1=t_H+1-t_I+1=9.84-6.06=3.78ms, Δ h=h_I+1-h_i=25-22=3.0m.L=h then_i+ Δ h/ (Δ t_I+1-Δ t_i) * Δ t_i=25+3/ (6.63-3.78) * 6.63=28.98m or L=h_I+1+ Δ h/ (Δ t_I+1-Δ t_i) * Δ t_I+1=22+3/ (6.63-3.78) * 3.78=28.98m.Accompanying drawing 9 is the capable figure of ripple of this 29m place actual measurement at the bottom of stake, and pile bottom reflection ripple and descending ripple are overlapping fully, prove to adopt this method to infer that stake is long, and its precision is higher.

Embodiment 2

Adopt adjacent stake single tube normal beam technique to detect the pile concrete construction quality

Certain engineering design is friction pile, stake footpath 1.8m, and the long 27m that is of stake, as shown in Figure 2,Acquisition Instrument 8 utilizes supersonic reflectoscope, detects infoundation pile 9sound detecting pipes 10 of adjacent 3.9m alongfoundation pile 1 pile body downwards and the compressional wave t time of advent that propagates from stake sidegeology soil layer 12_i, its result as shown in Figure 12, because geology is simple relatively, the formation travel time is relatively stable, thus the criterion that the judgement of pile body concrete quality can adopt single pile single tube normal beam technique detect to judge, from t_i-h_iAs seen curve does not have tangible evagination and the phenomenon that adds up, and thinks that this pile body concrete quality is complete, utilize the anti-stake of asking of soil layer velocity of wave long with an appearance symbol is provided.At t_i-h_iCurve has indent phenomenon, t_iWhen obviously reducing, think that pile body reaming occurs at the 15m place.

All the other are withembodiment 1.

Embodiment 3

Adopt adjacent stake single tube normal beam technique to survey all geology of stake

As shown in Figure 2, adopt adjacent stake single tube normal beam technique to survey all geology soil layer situations of stake, wherein adopt single tube normal beamtechnique signal processor 7 andAcquisition Instrument 8 to constitute knockdown seismic detector, wave detector adopts the highly sensitive ultrasonic transducer of RS-YH45III wideband, andAcquisition Instrument 8 utilizes supersonic reflectoscope in this example.The cross hole method wave velocity testing technology of analogy geology detecting, withfoundation pile 1 as feeler lever, adopt heavier power rod to impact pile crown on the stake top, make on the pile body vibration wave that produces downwards and propagate to the stake side periphery, the receiver hole that test needs usefulness is the directsound detecting pipe 10 in the sharpadjacent stake 9 then, also be the engineering existence conditions, needn't carry out geotechnical boring, setting of casing and grouting.

Accompanying drawing 13 is the t-h correlation diagram of this actual measurement and the stratum V-h distribution map of calculating.For accurately measuring the velocity of wave of geology soil layer, two engineering stakes are full pile.Pile Foundations Design is socketed pile, the long 22.2m of stake, and stake footpath 2m, two pile spacings are from 9.8m.

Adopt v simultaneously_i=S/ (t_i-h_i/ c_i) and

Calculate the longitudinal wave velocity of geology soil layer.

In conjunction with the geological exploration report, judge that this stake begins to embed decomposed rock near 18m, embed little decomposed rock at the 20m place.Think and near 17m, have a geology interlayer.

Be to survey the geology state of engineering foundation pile comprehensively, can utilize the plane relation of engineering stake, stake with between combined detection and carry out the analysis-by-synthesis of landforms.

Be more accurate detection stratum longitudinal wave velocity, as shown in Figure 15, on the sound detecting pipe of another farther adjacent stake, lay another wave detector more synchronously, the wave detector that increases is connected on another receive path of Acquisition Instrument, by measuring the time difference and the calculating of the relation between the pitch-row geology soil layer velocity of wave that two wave detectors receive signal.

All the other are withembodiment 2.

Embodiment 4

Adopt geology hole single tube normal beam technique to detect pile quality and geological condition

As shown in Figure 3, in the other boring of stake, adopt hydrophone as wave detector, adopt adjacent hole single tube normal beam technique to detect and evaluation pile body concrete quality and geology soil layer situation.

All the other are withembodiment 2 andembodiment 3.

Embodiment 5

Adopt geology hole single tube normal beam technique to detect the quality of existing building foundation pile

As shown in Figure 3, in the other boring of existing building foundation pile stake, the architectural employing power rod as cushion cap above pile foundation knocks exciting, when detecting the arrival of compressional wave in the hole, utilizes t_i-h_iThe relationship analysis pile body concrete quality that adds up of relation curve is long with the judgement stake, and utilizes the time-histories relation to ask the longitudinal wave velocity of calculating the stratum, the analysis stratum condition.

All the other are withembodiment 4.

Embodiment 6

Adopt two wave detectors to detect the pile concrete construction quality

As shown in Figure 16, on same sound detecting pipe, lay another wave detector simultaneously, the wave detector that increases is connected on another receive path of Acquisition Instrument, receive the time difference of signals and the concrete velocity of wave of the relation calculating pile body pile cutoff of the two detector discrepancy in elevation by measuring two wave detectors

All the other are withembodiment 1

Embodiment 7

A kind of single tube normal beam technique signal processor

As shown in Figure 4, voltage amplifier I and voltage amplifier II all adopt the operational amplifier of 1/4TL084 to constitute in-phase amplification circuit, other adopts 1/4TL084 to constitute single limit voltage comparator circuit, wherein with the potentiometer adjustment doors position of rationing the power supply, adopt 1/4TL084 to constitute the in-phase voltage add circuit, constitute the monostable trigger circuit with a slice CD4011, adopt two 9V batteries as power supply.Single tube normal beam technique signal processor is provided with two input interfaces of sensor and wave detector simultaneously, a signal output interface that is synthesized by voltage adder circuit, and a synchronization pulse output interface.

All the other are withembodiment 1.

Embodiment 8

Adopt wireless transmissioning mode to detect the pile concrete construction quality

As shown in Figure 14,sensor 5 is directly installed on the power hammer, on same sound detecting pipe, lay another wave detector simultaneously, the wave detector that increases is connected on another receive path of Acquisition Instrument, receives the time difference of signals and the velocity of wave of the relation calculating pile body pile cutoff of the two detector discrepancy in elevation by measuring two wave detectors.

All the other are withembodiment 1.

Embodiment 9

Adopt the single tube normal beam technique as the aided detection method of pile foundation nondestructive testing

For improving detection technique and the service level of sound wave transmission method, following suggestion is proposed:

1. should be adopting single pile single tube normal beam technique examine and determine the longitudinal wave velocity of pile concrete apart from the stake about 1m in end place, as the evaluation foundation of pile concrete construction quality level, also as the pile body velocity of wave average of dynamic measurement of pile employing.

2. during ultrasonic transmission beam method detected, on the low side when the actual measurement velocity of wave, or pile body should adopt the true velocity of wave of single pile single tube normal beam technique calibrating pile concrete when occurring departing from the maximum value or minimum value of physical significance fully.

3. during ultrasonic transmission beam method detects, when finding that major defect appears in pile body, should adopt the verification of single pile single tube normal beam technique, avoid occurring locally when pressing from both sides little defective such as mud when the sound detecting pipe periphery, judge by accident and be great quality problems such as serious undergauge, broken pile.

4. ultrasonic transmission beam method detects when pile body can't transmission or received weak output signal, should adopt the verification of single pile single tube normal beam technique, avoids when the corrosion of sound detecting pipe inwall, outer wall mud skin is thicker or sound detecting pipe and concrete break away from when splitting, ultrasonic wave can't transmission and by mistake survey judge by accident.

5. bury the stake of 2 sound detecting pipes underground, wherein 1 pipe during 1 pipe plug plug, should adopt the verification of single pile single tube normal beam technique on earth, and in conjunction with sound wave transmission method actual measurement synthetic determination as a result partly, length is appropriate to the occasion in conjunction with judgements such as dynamic measurement of pile when plugging.

6. bury the stake of 3 sound detecting pipes underground, 2 pipes are wherein arranged on earth, during 1 pipe plug plug, should adopt the verification of single pile single tube normal beam technique, in conjunction with sound wave transmission method actual measurement synthetic determination as a result partly.

7. bury the stake of 3 sound detecting pipes underground, wherein have only 1 pipe on earth, during 2 pipe plug plugs, should adopt the verification of single pile single tube normal beam technique, in conjunction with sound wave transmission method actual measurement synthetic determination as a result partly, length is appropriate to the occasion in conjunction with judgements such as dynamic measurement of pile when plugging.

8. bury the stake of 4 sound detecting pipes underground, 3 pipes are wherein arranged on earth, during 1 pipe plug plug, should adopt the verification of single pile single tube normal beam technique, in conjunction with sound wave transmission method actual measurement synthetic determination as a result partly.

9. bury the stake of 4 sound detecting pipes underground, 2 pipes are wherein arranged on earth, during 2 pipe plug plugs, should adopt the verification of single pile single tube normal beam technique, except surveying synthetic determination as a result partly in conjunction with sound wave transmission method, length is appropriate to the occasion in conjunction with judgements such as dynamic measurement of pile when plugging.

10. bury the stake of 4 sound detecting pipes underground, wherein have only 1 pipe on earth, during 3 pipe plug plugs, should adopt the verification of single pile single tube normal beam technique, removing should be in conjunction with the measured result synthetic determination of sound wave transmission method and dynamic measurement of pile, the verification of should loosing core in case of necessity.

11. all sound detecting pipes all stop up, when sound detecting pipe come-up or sound detecting pipe do not bury at the bottom of the stake, should adopt the verification of single pile single tube normal beam technique, when arriving by measuring the pile bottom reflection ripple, the actual stake of verification is long, in conjunction with sound wave transmission method actual measurement synthetic determination as a result partly, the check of should loosing core in case of necessity.

For improving detection technique and the service level of low strain reflected, following suggestion is proposed:

1. utilize the longitudinal wave velocity of single pile single tube normal beam technique detection as pile body velocity of wave average.

2. when 2L/C strong oscillator signal influence occurs and judges constantly, should adopt concrete quality that adjacent stake or adjacent hole single tube normal beam technique householder method verify pile body with long.

3. for super long pile, manually digging hole filling pile etc., in the time of can't detecting pile body and stake end signal, should adopt concrete quality and the stake of adjacent stake or adjacent hole single tube normal beam technique householder method checking pile body long.

4, for prefabricated tubular pile, can consider wave detector directly is put into that (the water place to be arranged) in the pipe and adopt single pile single tube normal beam technique to detect concrete quality and the stake of pile body long.

5. for socketed pile and bearing pile, the reflection wave signal of homophase at the bottom of stake, occurs, or time-domain curve is not seen into the rock signal and when not having pile bottom reflection ripple signal, should adopt adjacent stake or adjacent hole single tube normal beam technique checking pile soil horizon situation.

Claims (10)

1. adopt the single tube normal beam technique to carry out the technology of pile quality detection and geology detecting, it is characterized in that checked object is steel concrete foundation pile (1), buried sound detecting pipe (2) or core-drawing hole (3) underground at foundation pile (1) pile body, its test macro comprises: power hammer (rod) (4), sensor (5), wave detector (6), single tube normal beam technique signal processor (7) and Acquisition Instrument (8).Power hammer (rod) (4) are knocked exciting at foundation pile (1) end face and are produced a compressional wave of propagating along pile body downwards, by on the end face of foundation pile (1) or in power, hammering sensor (5) the detection knocking of installing (rod) (4) into shape, in sound detecting pipe (2) or core-drawing hole (3), detect the transmitting signal that knocks compressional wave by wave detector (6), measure wave detector (6) and lay the degree of depth that enters below foundation pile (1) end face, sensor (5) and wave detector (6) are connected respectively to the input of single tube normal beam technique signal processor (7), the major function of single tube normal beam technique signal processor (7) be with the detected knocking of sensor (5) be processed into one with knock synchronous single pulse signal of exciting moment, and synchronization pulse is added in the signal that wave detector (6) detects, signal after will handling is again delivered to Acquisition Instrument (8), carry out data acquisition by Acquisition Instrument (8), storage and initial analysis, measure the propagation time difference of compressional wave and calculate the longitudinal wave velocity of foundation pile, the length of the size by analyzing longitudinal wave velocity and the relation judgement foundation pile (1) of propagation time difference and the detection degree of depth, pile body concrete quality.

2. employing single tube normal beam technique as claimed in claim 1 carries out the technology of pile quality detection and geology detecting, it is characterized in that in the adjacent stake sound detecting pipe (10) of adjacent foundation pile (9) or adjacent stake core-drawing hole (11) by wave detector (6) detect knock compressional wave along foundation pile (1) pile body downwards and from the signal of stake side geology soil layer (12) propagation, the time of advent of measuring compressional wave is poor, measure wave detector (6) and lay the degree of depth that enters below foundation pile (1) end face, judge the length of foundation pile (1) by the relation of analyzing propagation time difference and the detection degree of depth, pile body concrete quality and reaming degree; Oneself knows the pile concrete velocity of wave, concerns according to time-histories and asks the longitudinal wave velocity of calculating geology soil layer (12), and differentiate a situation of all geology soil layers (12) and go into the rock situation with the analysis foundation pile.

3. employing single tube normal beam technique as claimed in claim 1 carries out the technology of pile quality detection and geology detecting, it is characterized in that in geotechnical boring (15) detecting by wave detector (6) and knock compressional wave along foundation pile (1) pile body and the signal of propagating from stake side geology soil layer (12) downwards, the time of advent of measuring compressional wave is poor, measure wave detector (6) and lay the degree of depth that enters below foundation pile (1) end face, ask the longitudinal wave velocity of calculating geology soil layer (12) according to the physical relation of time-histories, and judge a situation of all geology soil layers (12), analyze foundation pile and go into the rock situation.

4. carry out the technology of pile quality detection and geology detecting as claim 1 to the described employing single tube of claim 3 normal beam technique, it is characterized in that a kind of single tube normal beam technique signal processor is by voltage amplifier I (7-1), voltage amplifier II (7-2), voltage comparator circuit (7-3), monostable trigger circuit (7-4), voltage adder circuit (7-5) and power circuit (7-6) are formed, the output of voltage amplifier I (7-1) is connected to the input of voltage comparator circuit (7-3), the output of voltage comparator circuit (7-3) is connected to the trigger end of monostable trigger circuit (7-4), the output of monostable trigger circuit (7-4) and voltage amplifier II (7-2) is connected respectively to two inputs of voltage adder circuit (7-5), by the voltage signal of the synthetic longitudinal elastic wave that knocks the exciting synchronization pulse of having superposeed of voltage adder circuit (7-5).

5. employing single tube normal beam technique as claimed in claim 4 carries out the technology of pile quality detection and geology detecting, the major function that it is characterized in that a kind of single tube normal beam technique signal processor be with the detected signal of sensor (5) be processed into one with knock synchronous single pulse signal of exciting moment, synchronization pulse is connected to the external trigger input interface of Acquisition Instrument (8), and control Acquisition Instrument (8) is gathered the signal of wave detector (6) synchronously.

6. employing single tube normal beam technique as claimed in claim 4 carries out the technology of pile quality detection and geology detecting, it is characterized in that a kind of single tube normal beam technique signal processor has increased wireless transmitter module (7-7) in the rearmost end of circuit, in Acquisition Instrument (8) inside or the outside corresponding wireless receiving module (13) has been installed.

7. carry out as claim 4 and the described employing single tube of claim 5 normal beam technique that pile quality detects and the technology of geology detecting, it is characterized in that a kind of Acquisition Instrument with single tube normal beam technique measuring ability, is that the circuit with single tube normal beam technique signal processor (7) is directly embedded in the existing Acquisition Instrument (8).

8. carry out the technology of pile quality detection and geology detecting as claim 1 to the described employing single tube of claim 7 normal beam technique, it is characterized in that Acquisition Instrument (8) comprising: dynamic testing of pile instrument, nonmetal ultrasonic detector, ultrasonic wave follow surveys instrument, high strain detector, engineering dynamic tester and seismic detector.

9. employing single tube normal beam technique as claimed in claim 1 carries out the technology of pile quality detection and geology detecting, it is characterized in that wave detector (6) comprising: broadband ultrasonic wave transducer, hydrophone, three-component geophone.

10. employing single tube normal beam technique as claimed in claim 1 carries out the technology of pile quality detection and geology detecting, it is characterized in that in sound detecting pipe (2) or core-drawing hole (3), having installed simultaneously wave detector (6) and wave detector II (14), the constant distance of two wave detectors of testing process, by measuring the time difference of same exciting ripple, measure the concrete velocity of wave of corresponding pile cutoff between two wave detectors.

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