CN1042991A - The test pile technology of vibratory drilling method and transfer function method combination - Google Patents
The test pile technology of vibratory drilling method and transfer function method combination Download PDFInfo
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- CN1042991A CN1042991A CN 88108160 CN88108160A CN1042991A CN 1042991 A CN1042991 A CN 1042991A CN 88108160 CN88108160 CN 88108160 CN 88108160 A CN88108160 A CN 88108160A CN 1042991 A CN1042991 A CN 1042991A
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- stake
- pile
- bearing capacity
- displacement
- transfer function
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- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The test pile technology of a kind of vibratory drilling method and transfer function method combination relates to the method for testing of pile foundation in the civil construction project.It is characterized in that, utilize the ultimate bearing capacity of single pile of measured rigidity of vibratory drilling method and transfer function method calculating and the ratio K of rigidity
r, determine the single pile actual carrying capacity.This technology is found the solution the relation between bearing capacity and the rigidity, and has changed the situation and the complete mode of determining bearing capacity of single pile by rule of thumb of small strain of big strain testing equipment heaviness, makes the bearing capacity of single pile measuring accuracy be significantly improved.
Description
The present invention relates to the method for testing of pile foundation in the civil construction project.
The dynamic pile testing method that adopts both at home and abroad is a lot of at present, mainly contains large-strain method and small Strain method two classes.Large-strain method is mainly used in the bearing capacity of detective pole, but since its to add load bigger, so testing apparatus heaviness, be not completely free of the worry of static test, in addition, its theoretical and imprecision also has many parameters to determine by test and dynamic and static testing comparison in the computing formula of foundation, therefore be difficult to the degree of accuracy that reaches higher.Small Strain method is mainly used in the quality of checking stake at present, for the bearing capacity value of stake, can only determine with dynamic and static testing comparison and experience, therefore has time error bigger.
The objective of the invention is to solve the bearing capacity of stake and the relation between the rigidity, thereby make the small strain dynamic measuring method of stake can more accurately record actual bearing capacity of single pile.
The method that technical solution of the present invention realizes, adopt stable state frequency sweep forced oscillation method (abbreviation vibratory drilling method) and transfer function method in conjunction with testing bearing capacity of single pile:
1, uses the stiffness K of vibratory drilling method detective pole
With the stake of constant exciting force F exciting, get the velocity admittance response curve (Fig. 1) of stake.V among the figure
0And F
0Be respectively the amplitude of a top vibration velocity V and exciting force F, f is an excited frequency.Calculate the dynamic stiffness K of stake thus
2, determine bearing capacity of single pile.Adopt transfer function method to calculate the relation of pile top load P and displacement S, i.e. P～S curve, the bearing capacity P that tries to achieve then
uRatio K with stiffness K
r, performing step:
Soil is to the friction resistance f(S of stake around d, the supposition stake) represent with following transport function form:
f（S）＝ (CfuS)/(Su+（C-1）S)
In the formula: fu is all native limit frictional resistances of stake; S
uBe corresponding displacement; S is the displacement in certain cross section of stake; C is a coefficient, depends on the relation of initial tangent line of transport function and limit frictional resistance.
E, correspondingly suppose unit area end resistance r(S
b):
r(S
b)= (CRuS
b)/(S
bu+(C-1)S
b)
In the formula: R
uBe ultimate bearing capacity of pile tip, S
BuFor corresponding displacement, S are held in stake
bBe pile end displacement, C is a coefficient.
F, ask the stake P～S relation curve, computing formula:
In the formula: u is the stake perimeter of section; A is that dowel section area: E is the pile concrete elastic modulus; L is that stake is long; Z be the stake cross section, F(S) be transport function f(S) original function.
F, the P～S curve of trying to achieve according to aforementioned e calculate the stiffness K of stake
j:
K
j＝Lim (P)/(S)
S→O
G, ask the ratio K of pile ultimate bearing capacity and rigidity
r:
Kr= (P＇
u)/(K
j)
Calculating limit bearing capacity P ' in the formula
uCan determine that the ultimate bearing capacity regulation of stake tries to achieve in (JGJ4-80) according to " industry with covil construction bored concrete pile foundation design and construction rules ".
H, calculating single pile actual carrying capacity P
u:
P
u＝η K
rK
In the formula: η is an experience factor; K
rRatio for pile ultimate bearing capacity and rigidity among the aforementioned g; K is the vibratory drilling method test rigidity of aforementioned 1 king-pile.
3, realize a kind of vibratory drilling method test macro of the present invention (Fig. 2), form by excitation system, dynamometric system and pick-up system.
Excitation system is made up of signal generator (1), power amplifier (2) and vibrator (3).Signal generator produces the sinusoidal signal of an a certain frequency, is amplified by power amplifier then, to promote the stake of vibrator exciting.
Dynamometric system is made up of force transducer (4), charge amplifier (5) and digital voltmeter (6).Force transducer is because the effect of power produces charge signal, and charge amplifier is enlarged into the voltage signal of certain value to charge signal, detects with digital voltmeter, thereby measures and control exciting force.
The pick-up system is made up of acceleration transducer (7), charge amplifier (8) and digital voltmeter (9).Acceleration transducer absorbs the signal of stake vibration, and this signal is amplified by charge amplifier, and is integrated acceleration speed, is read by digital voltmeter at last.
The present invention has changed the situation and the complete mode of determining bearing capacity of single pile by rule of thumb of small strain of big strain testing equipment heaviness.Utilize transfer function method to calculate the bearing capacity of stake and the relation between the rigidity, make of the influence of principal element such as soil property situation around long, the dowel section area of stake, the stake to concerning between the bearing capacity of stake and the rigidity, can both accurately consider, avoid the one-sidedness and the narrow property of usable range of experience factor, made the bearing capacity of single pile measuring accuracy obviously improve.
Claims (4)
1, the test pile technology of a kind of vibratory drilling method and transfer function method combination, adopt the stake of constant exciting force exciting, get the velocity admittance response curve of stake, calculate the dynamic stiffness K of stake according to this, it is characterized in that adopting again transfer function method to calculate the P～S curve of stake, and calculate the stiffness K of stake
j=
Lim S → O(P)/(S), try to achieve the ultimate bearing capacity P ' of stake then
uWith stiffness K
jRatio K
r, calculate single pile actual carrying capacity P at last
u=η K
rK, the η in the formula are empirical data.
2,, it is characterized in that the computing formula of the P～S curve of described stake is according to the described test pile technology of claim 1:
In the formula: S
bBe pile end displacement, S is the displacement in certain cross section of stake, and u be a stake perimeter of section, and A is a dowel section area, and E is the pile concrete elastic modulus, and L be that stake is long, and Z be a stake cross section, F(S) is a supposition native on every side friction resistance f(S to stake) original function, r(S
b) be corresponding unit area end resistance, C
1Be coefficient.
3, according to claim 1 or 2 described test pile technology, it is characterized in that described friction resistance f(S) the transport function form be: f (S)=(Cfus)/(Su+ (C-1) S), in the formula: f
uBe native limit frictional resistance of stake week, S
uBe corresponding displacement, C is a coefficient, depends on the relation of initial tangent line of transport function and limit frictional resistance, and S is the displacement in certain cross section of stake.
4, according to claim 1 or 2 described test pile technology, it is characterized in that described end resistance r (S
b)=(CR
uS
b)/(S
Bu+ (C-1) S
b), in the formula: R
uBe ultimate bearing capacity of pile tip, S
BuFor corresponding displacement, S are held in stake
bBe pile end displacement, C is a coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88108160 CN1017749B (en) | 1988-11-24 | 1988-11-24 | Trial staking technology combining vibration method and transfer function method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88108160 CN1017749B (en) | 1988-11-24 | 1988-11-24 | Trial staking technology combining vibration method and transfer function method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1042991A true CN1042991A (en) | 1990-06-13 |
| CN1017749B CN1017749B (en) | 1992-08-05 |
Family
ID=4834969
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88108160 Expired CN1017749B (en) | 1988-11-24 | 1988-11-24 | Trial staking technology combining vibration method and transfer function method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1017749B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102877490A (en) * | 2012-09-18 | 2013-01-16 | 河海大学 | Method for detecting quality of large-diameter tubular pile at low strain |
| CN105386439A (en) * | 2015-10-10 | 2016-03-09 | 长沙理工大学 | Design method of friction pile |
| CN107036774A (en) * | 2017-01-23 | 2017-08-11 | 中国机械工业集团有限公司 | A kind of assessment technology of strong rammer operation to concrete structure vibration effect |
| CN109487835A (en) * | 2018-09-30 | 2019-03-19 | 中国铁道科学研究院集团有限公司铁道建筑研究所 | The detection method and detection device of pile foundation allowable bearing |
| CN111272586A (en) * | 2020-02-22 | 2020-06-12 | 江苏东南特种技术工程有限公司 | Method for detecting vertical load of existing building structure by exciting vibration force |
| CN113158291A (en) * | 2021-03-01 | 2021-07-23 | 中国铁路设计集团有限公司 | Method for calculating length of friction pile of pier under earthquake action |
-
1988
- 1988-11-24 CN CN 88108160 patent/CN1017749B/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102877490A (en) * | 2012-09-18 | 2013-01-16 | 河海大学 | Method for detecting quality of large-diameter tubular pile at low strain |
| CN102877490B (en) * | 2012-09-18 | 2014-06-11 | 河海大学 | Method for detecting quality of large-diameter tubular pile at low strain |
| CN105386439A (en) * | 2015-10-10 | 2016-03-09 | 长沙理工大学 | Design method of friction pile |
| CN105386439B (en) * | 2015-10-10 | 2017-04-19 | 长沙理工大学 | Design method of friction pile |
| CN107036774A (en) * | 2017-01-23 | 2017-08-11 | 中国机械工业集团有限公司 | A kind of assessment technology of strong rammer operation to concrete structure vibration effect |
| CN107036774B (en) * | 2017-01-23 | 2019-02-05 | 中国机械工业集团有限公司 | A kind of assessment technology that strong rammer operation influences concrete structure vibration |
| CN109487835A (en) * | 2018-09-30 | 2019-03-19 | 中国铁道科学研究院集团有限公司铁道建筑研究所 | The detection method and detection device of pile foundation allowable bearing |
| CN111272586A (en) * | 2020-02-22 | 2020-06-12 | 江苏东南特种技术工程有限公司 | Method for detecting vertical load of existing building structure by exciting vibration force |
| CN113158291A (en) * | 2021-03-01 | 2021-07-23 | 中国铁路设计集团有限公司 | Method for calculating length of friction pile of pier under earthquake action |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1017749B (en) | 1992-08-05 |
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