CN101078661B - Method and instrument for determining hammer force in foundation pile high stress drive detection - Google Patents
Method and instrument for determining hammer force in foundation pile high stress drive detection Download PDFInfo
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- CN101078661B CN101078661B CN200710122947XA CN200710122947A CN101078661B CN 101078661 B CN101078661 B CN 101078661B CN 200710122947X A CN200710122947X A CN 200710122947XA CN 200710122947 A CN200710122947 A CN 200710122947A CN 101078661 B CN101078661 B CN 101078661B
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Abstract
The invention relates to a method for measuring impact force when pile foundation high strain power is measured and the matched instrument, belonging to the measuring field for pile foundation engineering quality in civil engineering. Extended instrument with conventional measuring method for pile foundation high strain power is used. By measuring acceleration of free-fall hammer body and pile head directly and carrying out low-pass filter to acceleration signal of hammer body, according to Newton second law impact force at pile top and inertia force at pile head are calculated respectively and after impact force at pile top is corrected by inertia effect impact force for measuring section position under pile top can be obtained. Because high-frequency interference in falling-hammer acceleration signal and inertia effect of pile head relates with geometrical dimension of falling hammer and inertia weight respectively and there is no relation with concrete material and stress-strain relationship. Furthermore signal measuring quality and accuracy for high-strain impact force wave of concrete pile can be improved. In addition, when the method is used in field measurement of grouting pile reinforcing cost of concrete pile head can be decreased properly and digging time for pile head can be saved.
Description
Technical field
The present invention relates to a kind of method and matching used acquisition and recording instrument that is used to measure hammer force in foundation pile high stress drive detects, belong to the pile foundation engineering quality testing field of civil engineering work.
Background technology
When the pile foundation engineering quality testing, often adopt foundation pile high stress drive to detect (also claiming high strain power stake testing) mode to the foundation pile vertical compression bearing capacity in the pile foundation and the detection of pile construction integrity.In traditional foundation pile high stress drive detects, the hammering Reeb on stake top and speed responsive are installed in by symmetry respectively and measure the cross section (approximately apart from stake top 2D, D is the diameter or the hem width of stake, as follows) 2 ring type strainometers and 2 accelerometer measures of locating, wherein the strain measurement value of the ring strain ga(u)ge output pile shaft material elastic modulus that need multiply by estimation just can be converted into the power value.Because most pile foundation materials are concrete, the difference of system stake or pile-formation process, the non-linear and heterogeneity of various degrees makes the hammer force wave measurement following problem occur:
(1) the impulsive force amplitude height of weight, concrete deformation is the linear elasticity scope head and shoulders above, non-linear making " elastic modulus " successively decreased with the increase of strain, it is higher to adopt the elastic modulus of low strain amplitude correspondence to multiply by the convert power value that obtains of actual measurement strain value, accuracy is low, and the pile bearing capacity numerical value amplification that causes analytical calculation in view of the above to obtain, dangerous to engineering.Under the coupling influence of hammering off-centre and concrete heterogeneity factor, the situation of hammering Reeb test crash occurs now and then especially, even is out of shape the excessive ring strain ga(u)ge that causes and damages.
(2) bored concrete pile test generally will be in the above scope in the measurement cross section of sensor installation (approximately apart from a stake top 2D) consolidation process pile crown again, time-consuming and increase the detection cost.If ring strain ga(u)ge directly is installed at untreated pile crown concrete side surface, the problem of increase of the probability of hammering Reeb test crash and ubiquity test force poor signal quality.
Content of the present invention
Measure the problem that exists based on hammer force in the above-mentioned present foundation pile high stress drive detection, the objective of the invention is to propose a kind of method and instrument of measuring hammer force, by this method and supporting testing tool, directly measure and calculate hammer force wave-wave shape, and then solve the problem of carrying out foundation pile high stress drive low, test force poor signal quality of hammer force test accuracy when detecting by traditional approach, be a kind ofly to substitute traditional ring strain ga(u)ge that utilizes and measure the convert method of hammer force of strain.
The present invention is by the acceleration signal of synchro measure free-falling hammer hammer body and pile body acceleration signal, the high frequency interference of the acceleration signal that longitudinal and transverse ripple on the hammer body is caused is carried out low-pass filtering, utilize Newton second law to calculate a top hammer force, utilize the acceleration measurement of measurement section under the stake top that the pile crown of measuring cross section to stake top scope is partly carried out the inertial effect correction again, thereby the hammer force of realization measurement section is measured.Its concrete grammar step is:
(1) utilize symmetry to be installed on the hammer body, can to measure the sensor of impact acceleration, and the signals collecting register instrument that links to each other with sensor, the impact acceleration that produces on hammer body during survey record weight free-falling bump stake top is the variation a of t in time
r(t);
(2) at free-falling hammer interfering frequency different frequently of longitudinal and transverse wave height in the hammer body that causes that bump or rub with guide piece, select filtering cutoff frequency or trap frequency, to acceleration signal a
r(t) carry out low-pass filtering or trap;
(3) utilize formula F
r(t)=m
ra
r(t) calculate hammering Reeb, a top time-history curves F
r(t), m in the formula
rQuality for free-falling hammer;
(4) utilize the sensor that is installed in measurement section depth place's stake side surface, can measures impact acceleration, and the signals collecting register instrument that links to each other with sensor, the impact acceleration that survey record produces on pile body when dropping hammer free-falling bump stake top is the variation a of t in time
p(t);
(5) utilize unintegrated acceleration time signal a
p(t), by formula F
p(t)=m
pa
p(t) calculate pile crown inertial force time-history curves F
p(t), a wherein
p(t) be installed in apart from the acceleration sensor outputs signals of the measurement section of stake top 1D～2D degree of depth, m for symmetry
pFor stake is pushed up to measuring pile crown quality of concrete in the section depth scope;
(6) utilize formula F (t)=F
r(t)-F
p(t) carry out the correction of pile crown inertial effect, calculate the hammer force time-history curves F (t) that measures section.
When adopting traditional foundation pile high stress drive to detect, hammering Reeb amount is the strain of measuring section by actual measurement, multiply by the pile shaft material elastic modulus conversion power value of estimation then, because piling concrete nonlinear and high stress level are impacted, " elastic modulus " is not constant, and the accuracy of conversion power value is low; Because hammering is eccentric and the heteropical coupling influence of piling concrete, causes the test force poor signal quality.And the extended pattern instrument of the present invention's to be it utilize compatible traditional foundation pile high stress drive detection mode---on the basis of two traditional acceleration analysis passages, be extended to the instrument of four acceleration analysis passages, by direct measurement drop hammer acceleration, calculate a top hammer force by Newton second law.When stake top hammer force being changed into measurement cross section hammer force, the high frequency interference of dropping hammer in the acceleration signal is only relevant with the inertial mass of physical dimension of dropping hammer and pile crown respectively with the pile crown inertial effect, irrelevant with concrete material and strain-stress relation, and then obviously improved the high strain hammering Reeb signal testing quality of concrete-pile, improved the accuracy of hammer force wave measurement; In addition, when adopting this method to carry out the detection of bored concrete pile scene, can suitably reduce concrete pile crown reinforcing scope and pile crown cutting depth, reduce the detection cost to a certain extent, improved detection efficiency.
The present invention is further elaborated below in conjunction with the specific embodiment of measuring method.
Description of drawings
Fig. 1 is measuring method of the present invention and necessary instrument principle of work synoptic diagram.
Fig. 2 is the hammering Reeb time-history curves that utilizes acquisition and recording instrument shown in Figure 1 to record.
Embodiment
Specific implementation method, step are:
(1) the middle part symmetry of the hammer body M1 hammer body in Fig. 1 is installed 2 sensors A 1 that can measure impact acceleration, in 2 sensors A 2 that can measure impact acceleration of pile body P side surface symmetry installation apart from the measurement plane P2 degree of depth place of stake top plane P 1 following 1D～2D; Acceleration transducer A1 links to each other with 4 passage acquisition and recording instrument A4 by signal wire A3 respectively with A2;
(2) calculating chart 1 midplane P1 obtains the inertial mass m of pile crown to the pile crown volume of plane P 2 depth rangees, the mass density that multiply by pile shaft material
p
(3) according to the physical dimension of free-falling hammer hammer body M1 among Fig. 1, default High frequency filter or trap cutoff frequency f
H
(4) as shown in Figure 1, hammer body M1 falls to clashing into stake top plane P 1 along saddle M2, utilizes the acquisition and recording instrument A4 that links to each other with signal wire A3, and synchronous acquisition is recorded in the impact acceleration signal a that the acceleration transducer A1 on the hammer body M1 produces
r(t) and the impact acceleration signal a that produces of the acceleration transducer A2 on pile body P
p(t);
(5) according to the height of interference wave frequency, select filtering cutoff frequency or trap frequency, to acceleration signal a
r(t) carry out low-pass filtering or trap;
(6) utilize formula F
r(t)=m
ra
r(t) calculate the hammering Reeb time-history curves F at top plane P 1 place
r(t);
(7) utilize formula F
p(t)=m
pa
p(t) calculate pile crown inertial force time-history curves F
p(t);
(8) utilize formula F (t)=F
r(t)-F
p(t) carry out the inertial effect correction, calculate the hammer force time-history curves F (t) at P2 place, measurement cross section as shown in Figure 2.
The sensor of measuring impact acceleration among the present invention does not limit, and it can adopt types such as piezoelectric type, pressure resistance type, condenser type; Equally, will not limit the suitable accent of the signal of acquisition and recording instrument, analog-to-digital conversion precision, sample frequency etc.
Claims (1)
1. measure the method for hammering Reeb when a foundation pile high stress detects, it is characterized in that it is by the drop hammer acceleration of hammer body and pile crown of direct measurement, high frequency interference ripple in the hammer body acceleration signal that drops hammer is carried out low-pass filtering or trap, calculate the hammer force on stake top and the inertial force of pile crown respectively by Newton second law, stake top hammer force is carried out obtaining the hammer force that following measurement section is pushed up in stake after the inertial effect correction, thereby realize the measurement of hammering Reeb, its concrete steps are:
(1) utilizes the symmetrical sensor a that is installed on the hammer body that drops hammer, measures impact acceleration, and the signal testing register instrument A that links to each other with measurement jerk acceleration transducer a, the impact acceleration time signal a that survey record produces on the hammer body that drops hammer when dropping hammer hammer body bump stake top
r(t);
(2) the longitudinal and transverse wave height frequency interference wave frequency that bumps or rub and cause in the hammer body that drops hammer according to drop hammer hammer body and guide piece is selected filtering cutoff frequency or trap frequency, to acceleration signal a
r(t) carry out low-pass filtering or trap;
(3) utilize formula F
r(t)=m
ra
r(t) calculate hammering Reeb, a top time-history curves F
r(t), m in the formula
rQuality for the hammer body that drops hammer;
(4) utilize the sensor b that is installed in measurement section depth place's stake side surface, measures impact acceleration, and the signal testing register instrument A that links to each other with measurement jerk acceleration transducer b, the impact acceleration time signal a that survey record produces on pile body when dropping hammer hammer body bump stake top
p(t);
(5) utilize unintegrated acceleration time signal a
p(t), by formula F
p(t)=m
pa
p(t) calculate pile crown inertial force time-history curves F
p(t), m
pFor stake is pushed up to measuring pile crown quality of concrete in the section depth scope;
(6) utilize formula F (t)=F
r(t)-F
p(t) carry out the inertial effect correction, calculate the hammer force time-history curves F (t) that measures section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200710122947XA CN101078661B (en) | 2007-07-05 | 2007-07-05 | Method and instrument for determining hammer force in foundation pile high stress drive detection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200710122947XA CN101078661B (en) | 2007-07-05 | 2007-07-05 | Method and instrument for determining hammer force in foundation pile high stress drive detection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101078661A CN101078661A (en) | 2007-11-28 |
| CN101078661B true CN101078661B (en) | 2010-06-30 |
Family
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|---|---|---|---|
| CN200710122947XA Expired - Fee Related CN101078661B (en) | 2007-07-05 | 2007-07-05 | Method and instrument for determining hammer force in foundation pile high stress drive detection |
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Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102268886B (en) * | 2010-06-04 | 2013-08-14 | 中国海洋石油总公司 | Method for detecting and evaluating design bearing capacity of pile foundation of offshore oil platform |
| CN102944692A (en) * | 2012-11-09 | 2013-02-27 | 江苏大学 | Detection system and detection method for hammer head speed of hydraulic counterblow hammer |
| CN103048075B (en) * | 2013-01-08 | 2015-07-29 | 浙江大学 | A kind of impact force testing device |
| CN105756667B (en) * | 2016-02-22 | 2019-02-12 | 青岛蓝天创先科技服务有限公司 | A kind of Punching Borehole Cast-in-place Concrete Pile block stamp enters the decision maker of design rock stratum |
| CN105759076B (en) * | 2016-03-09 | 2019-12-24 | 西北工业大学 | Strain type acceleration sensor with forging hammer striking force detection integrated structure |
| CN107246840A (en) * | 2017-07-14 | 2017-10-13 | 浙江大学 | A kind of dynamic strain measuring method based on piezo-electric effect |
| CN107356317B (en) * | 2017-08-21 | 2023-04-07 | 兰州交通大学 | Transverse wave attenuation measuring device and method |
| CN109138005B (en) * | 2018-08-30 | 2021-05-07 | 中建七局第四建筑有限公司 | Construction process for existing load-bearing engineering foundation pile detection structure measures |
| EP3756831A1 (en) * | 2019-06-25 | 2020-12-30 | Hilti Aktiengesellschaft | Sensor to detect a mechanical stress on the battery pack |
| CN112012252B (en) * | 2020-08-29 | 2021-08-03 | 东南大学 | Integrated fast-loading method pile foundation detection device and detection method thereof |
| CN113404095B (en) * | 2021-04-12 | 2022-03-01 | 昆山求正工程质量检测有限公司 | Detection equipment and detection method for high strain of foundation pile |
| CN114354040A (en) * | 2021-12-06 | 2022-04-15 | 河北燕兴机械有限公司 | Testing device for firing energy of firing mechanism |
-
2007
- 2007-07-05 CN CN200710122947XA patent/CN101078661B/en not_active Expired - Fee Related
Non-Patent Citations (4)
| Title |
|---|
| JP特开2005-330743A 2005.12.02 |
| 全文. |
| 李大展，陈凡.采用CASE法试桩的技术和操作要求.建筑科学 4.1989,(4),26-30. |
| 李大展,陈凡.采用CASE法试桩的技术和操作要求.建筑科学 4.1989,(4),26-30. * |
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|---|---|
| CN101078661A (en) | 2007-11-28 |
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