CN108716226A - A kind of improved club-footed pile self-balanced static-load testing device and method - Google Patents
A kind of improved club-footed pile self-balanced static-load testing device and method Download PDFInfo
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- CN108716226A CN108716226A CN201810410733.0A CN201810410733A CN108716226A CN 108716226 A CN108716226 A CN 108716226A CN 201810410733 A CN201810410733 A CN 201810410733A CN 108716226 A CN108716226 A CN 108716226A
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- 238000012360 testing method Methods 0.000 title claims abstract description 88
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- 238000006073 displacement reaction Methods 0.000 claims abstract description 110
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 73
- 238000005259 measurement Methods 0.000 claims abstract description 33
- 230000002787 reinforcement Effects 0.000 claims abstract description 23
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 20
- 239000010959 steel Substances 0.000 claims abstract description 20
- 238000007689 inspection Methods 0.000 claims abstract description 4
- 239000002689 soil Substances 0.000 claims description 13
- 238000002474 experimental method Methods 0.000 claims description 9
- 238000005266 casting Methods 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 4
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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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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/22—Piles
- E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
- E02D5/38—Concrete or concrete-like piles cast in position ; Apparatus for making same making by use of mould-pipes or other moulds
- E02D5/44—Concrete or concrete-like piles cast in position ; Apparatus for making same making by use of mould-pipes or other moulds with enlarged footing or enlargements at the bottom of the pile
Abstract
The invention discloses a kind of improved club-footed pile self-balanced static-load testing devices, including：Stake holes；Steel reinforcement cage stretches in stake holes；Auxiliary survey reinforcing bar is located in steel reinforcement cage, and auxiliary survey reinforcing bar blocks simultaneously bind reinforcing rib meter in variable cross-section position；Load box is located at the bottom of stake holes；Pressure oil pump, pressure oil pump are located at the outside of chamber and are connected to load box by oil pipe；Upper displacement measuring staff and bottom offset measuring staff are buried to be fixedly connected in stake holes and respectively with the upper plate of load box and lower plate；Displacement measurement equipment is installed on the top of displacement measuring staff and bottom offset measuring staff；Data acquisition equipment, the data information for receiving reinforcing rib meter and the acquisition of displacement measurement equipment.The invention also discloses a kind of improved club-footed pile self-balanced static-load testing methods.The present invention can successfully solve the problems, such as the testing inspection of other a variety of base expanding and base expanding pile bearing capacitys such as mountain area, other complex site iron tower of power transmission line and communication tower basis.
Description
Technical field
The present invention relates to static load test technical field, specially a kind of improved club-footed pile self-balanced static-load testing device
And method.
Background technology
The static load test (such as accumulation load method, anchored pile-testing method) for the stake that China uses at this stage is that detection pile bearing capacity is the most reliable
A kind of method, both of which is to withstand on stake top using oil jack to be further applied load, and the counter-force of jack, the former passes through anti-
Heap weight on power frame balances therewith, and counter-force is transmitted to anchoring pile by the latter by reaction frame, the resistance to plucking dynamic balance with anchoring pile.Existing for it
Main problem is：The former must solve load source, stacking and the transportation problem of hundreds of tons of even upper kilotons, and the latter must be provided with
More anchoring piles and counter-force crossbeam, not only needed for somewhat expensive, the time is longer, and is easily limited by tonnage and site condition, with
The bearing capacity of many large-tonnage stakes and the stake in special place (such as mountainous region, bridge pier) is caused often to cannot get accurate data, foundation pile is dived
Power cannot be played rationally, this is a great problem of pile foundation field face.
To solve above problem, American scholar Osterberg first proposed self-balancing approach method of testing the eighties, and in
The mid-80 has carried out the research of pile bearing capacity test method, is applied successfully in bridge piling bar first, gradually promotes later
To various pile-type.Self-balancing approach provides counter-force to determine the side frictional resistance of bearing capacity of single pile and pile soil horizon using pile-soil system itself
Power, end resistance are close to the test method that vertical compression (pulls out) stake actual working state.Its principle is shown referring to Fig.1, is
In pile body or stake end buried loads case 31, compression test, preloading is replaced using epimere stake dead weight, epimere stake pile side friction
The anchoring pile in weight or anchored pile-testing method in method is to provide counter-force.When experiment, load box cavity is applied from stake top by petroleum pipeline
Pressure, case lid are open with bottom, while applying power equal in magnitude, that direction is opposite to epimere stake 30 and hypomere stake 32, promote
The frictional resistance of epimere stake 30 and hypomere stake 32 and the end resistance of supporting course 33 play a role, when pile-soil system destroys or meet engineering
Actual requirement when stop experiment.Working condition and the state of stake in actual work when self-balanced test is different, is
Close to a kind of approximation method of actual working state.
Therefore it buries in test load box to need to block filling pile cage of reinforcement, load box is respectively to upper during experiment
Section stake and hypomere stake are loaded, although can be tested with injecting treatment, for anti-horizontal force and resistance to plucking stress after experiment
Stake remains defect or security risk after having detected.
Invention content
For overcome the deficiencies in the prior art, one of the objects of the present invention is to provide a kind of improved club-footed pile self-balancings
Static-load testing device, can successfully solving mountain area, other complex site iron tower of power transmission line and communication tower basis etc., other are more
The test problems of kind base expanding and base expanding pile bearing capacity, can be detected vertically pulling-resistant, vertical compression bearing capacity respectively, be not necessarily to reinforcing bar
Cage blocks.
One of to achieve the above object, the present invention provides the following technical solutions：
A kind of improved club-footed pile self-balanced static-load testing device, including：
Stake holes, the stake holes include the non-reaming part of stake holes epimere and positioned at the reaming part of the stake holes hypomere,
The non-reaming part and reaming part are respectively used to form the upper pile body of club-footed pile and lower pile body after casting concrete, it is described on
Pile body and lower pile body are using variable cross-section as interface；
Steel reinforcement cage, the steel reinforcement cage stretch in the stake holes；
Auxiliary survey reinforcing bar, the auxiliary survey reinforcing bar are located in steel reinforcement cage, and the auxiliary survey reinforcing bar packet blocks bind in variable cross-section position
Reinforcing rib meter；
Reinforcing rib meter, the reinforcing rib meter are located at the variable cross-section position；
Load box, the load box are located at the bottom of stake holes, the i.e. bottom of reaming part；
Pressure oil pump, the pressure oil pump are located at the outside of stake holes and are connected to load box by oil pipe；
Upper displacement measuring staff, the upper displacement measuring staff are stretched into the stake holes and are fixedly connected with the upper plate of load box；
Bottom offset measuring staff, the bottom offset measuring staff are stretched into the stake holes and are fixedly connected with the lower plate of load box；
Displacement measurement equipment is installed on the upper displacement measuring staff and bottom offset measuring staff such as dial gauge or displacement sensor
Top；
Data acquisition equipment, the data information for receiving the reinforcing rib meter and the acquisition of displacement measurement equipment.
The outside of the upper displacement measuring staff and bottom offset measuring staff is arranged with displacement bar protection pipe respectively and bottom offset bar is protected
Pillar.
The auxiliary quantity for surveying reinforcing bar, upper displacement measuring staff and bottom offset measuring staff is two, is uniformly distributed.
The auxiliary main reinforcement equal diameter for surveying reinforcing bar and steel reinforcement cage, the auxiliary length for surveying reinforcing bar is not less than pile body stake diameter
2.5-3 again.
The second object of the present invention is to provide a kind of improved club-footed pile self-balanced static-load testing method, can succeed
The test problems of other a variety of base expanding and base expanding pile bearing capacitys such as mountain area, other complex site power transmission line columns and communication tower basis are solved,
Vertically pulling-resistant, vertical compression bearing capacity can be detected respectively, without blocking steel reinforcement cage.
To achieve the above object two, the present invention provides the following technical solutions：
A kind of improved club-footed pile self-balanced static-load testing method, includes the following steps：
Test platform is built according to the club-footed pile self-balanced static-load testing device described in one of above-mentioned purpose；
To age in casting concrete to stake holes；
Step stress test；
Unloading test step by step；
Test data is obtained according to the step stress test and step by step unloading test and test result is analyzed.
The step stress test includes：
Equivalent step by step is carried out to load box and loads capacity value, the capacity value of every grade of load is the 1/ of load box maximum load amount
, the capacity value of every grade of load is classification capacity value；
To every grade load after displacement carry out survey reading, at every grade load after 5min, 15min, 30min, 45min with
And 60min surveys the displacement that read bit moves measurement equipment, after 60min at interval of 30min survey read bit move the displacement of measurement equipment with
And reinforcing rib meter reading；
Amplitude of variation of the capacity value of every grade of load in surveying read procedure must not exceed ± the 10% of classification capacity value；
When change in displacement rate when every grade of load reaches opposite stability criterion, then carry out the operation of next stage load.
The unloading test step by step includes：
Equivalent step by step is carried out to load box and unloads capacity value, the capacity value of every grade of unloading is 2 times that are classified capacity value；
Every grade of unloading maintains 1h, and survey reading is carried out to the displacement after every grade of unloading in the 1h, and the after being unloaded at every grade
15min, 30min and 60min survey the displacement and reinforcing rib meter reading that read bit moves measurement equipment；
When discharging quantity after unloading is zero, displacement and reinforcing rib meter reading that read bit moves measurement equipment are surveyed, remembers and is surveyed
Displacement is residual displacement amount, and the survey read time of residual displacement amount is no less than 3h, discharging quantity after unloading be zero after the
5min, 30min respectively survey reading once, are surveyed at interval of 30min after 30min and read a residual displacement amount；
Amplitude of variation of the capacity value of every grade of unloading in surveying read procedure must not exceed ± the 10% of classification capacity value.
During step stress test, occur under following either case, stops step stress test：
During certain grade of load test, displacement increment or bottom offset increment are not less than its previous stage load test mistake thereon
5 times of bottom offset increment in journey, and displacement or bottom offset amount are more than 40min thereon；
During certain grade of load test, displacement increment or bottom offset increment are more than its previous stage load test process thereon
5 times of middle bottom offset increment, and relatively stable mark has not yet been reached in the change in displacement rate during interior this grade of load test for 24 hours
It is accurate；
Reach maximum experiment loading capacity, and tests the change in displacement rate under loading capacity in the maximum and reach relatively stable mark
It is accurate；
Load box has reached load box maximum load amount or upper displacement and bottom offset amount has reached load box stroke.
It is described that test result is analyzed, including：
Draw the relation curve of the relation curve and displacement and load or unload time of capacity value and displacement；
Determine epimere stake limit loaded value and hypomere stake limit loaded value；
It calculates and obtains vertical allowable load capacity of single pile；
It calculates and obtains vertical ultimate uplift resistance of single pile；
Determine single pile vertical resistance pressure characteristic load bearing capacity and unit for single-pile vertical anti-pulling characteristic load bearing capacity.
It is described calculate obtain vertical allowable load capacity of single pile formula be：
Fud=Qud
Fuu=FAxle power
Wherein, QuFor vertical allowable load capacity of single pile, FuuAnd FudThe respectively single-pile vertical orientation of epimere stake and hypomere stake
Compressive ultimate bearing capacity, FAxle powerFor the pile shaft force value of the above position of variable cross-section, QudActual measurement for load box hypomere stake finally loads
Value；W is the sum of dead weight and impost of load box epimere stake, and the impost includes the weight of the superfilled height of stake top or more
Amount, empty pile cutoff mud or Cast-in-situ Piles in Sand-filling and soil dead weight；γ is load box epimere pile side resistance correction factor, according to load upper box part
The type of soil determines；
The pile shaft force value F of the above position of variable cross-sectionAxle powerIt is calculated according to following formula：
FReinforcing rib meter i=ki(fii 2-f0i)
Wherein：kiFor producer's calibration coefficient of i-th reinforcing bar flowmeter sensor；fiiFor i-th reinforcing rib meter this monitoring frequency
Reading；f0iFor the original frequency modulus of i-th reinforcing bar flowmeter sensor；FReinforcing rib meter iFor the axle power of i-th reinforcing rib meter；It is n
The average value of the axle power of reinforcing rib meter；FAxle powerFor the pile shaft force value of the above position of variable cross-section of actual measurement；N is concrete support reinforcing bar
The radical of meter；AReinforcing barFor reinforcing rib meter sectional area；AIt is mixedFor the sectional area of pile concrete, EIt is mixedFor modulus of elasticity of concrete；ESteelFor reinforcing bar
Elasticity modulus；
The vertical ultimate uplift resistance of single pile PuCalculation formula be：
=wherein, γ2For by the resistance to plucking frictional resistance conversion coefficient of inspection stake；
The single pile vertical resistance pressure characteristic load bearing capacity is the 50% of single pile vertical resistance pressure bearing capacity；
The unit for single-pile vertical anti-pulling characteristic load bearing capacity is the 50% of unit for single-pile vertical anti-pulling bearing capacity.
Compared with prior art, the improved club-footed pile self-balanced static-load testing device of the present invention and method, advantage
It is：The present invention can successfully solve other a variety of base expanding and base expandings such as mountain area, other complex site power transmission line columns and communication tower basis
The test problems of pile bearing capacity are directed to and need to arrange place in the large-scale static load equipment of transport, lay road, expend a large amount of manpowers
Material resources are unfavorable for the case where traditional foundation pile static loading test is implemented, and selection uses this method, can be to vertically pulling-resistant, vertical compression
Bearing capacity is detected respectively, without blocking steel reinforcement cage.
Description of the drawings
Fig. 1 is the schematic diagram of existing Self-balanced Testing Method；
Fig. 2 is the structural schematic diagram of the improved club-footed pile self-balanced static-load testing device of the present invention.
In figure：1, load box；2, upper displacement bar protection pipe；3, reinforcing rib meter；4, steel reinforcement cage main reinforcement；5, data acquisition equipment；
6, data acquire cable；7, upper displacement measuring staff；8, displacement measurement equipment；9, bottom offset measuring staff；10, bottom offset bar protection pipe；11,
Reference stake；12, oil pipe；13, datum line beam；14, pressure oil pump；15, auxiliary survey reinforcing bar；16, stirrup；17, upper pile body；18, lower pile body；
19, stake week rock-soil layer；20, grouting behind shaft or drift lining pipe；30, epimere stake；31, load box；32, hypomere stake；33, supporting course.
Specific implementation mode
In the following, in conjunction with attached drawing and specific implementation mode, the present invention is described further, it should be noted that not
Under the premise of conflicting, new implementation can be formed between various embodiments described below or between each technical characteristic in any combination
Example.
A kind of improved club-footed pile self-balanced static-load testing device, please refers to shown in Fig. 2 comprising stake holes, steel reinforcement cage, auxiliary
Survey reinforcing bar 15, reinforcing rib meter 3, load box 1, pressure oil pump 14, upper displacement measuring staff 7, bottom offset measuring staff 9, displacement measurement equipment 8 and
Data acquisition equipment 5.
Wherein, the stake holes, periphery are stake week rock-soil layer 19, and stake holes includes the non-reaming part and position of stake holes epimere
In the reaming part of the stake holes hypomere, the non-reaming part and reaming part form base expanding and base expanding after being respectively used to casting concrete
The upper pile body 17 and lower pile body 18 of stake, upper pile body 17 and lower pile body 18 are using variable cross-section as interface；It is set on the outside of stake holes
It is equipped with reference stake 11 and datum line beam 13.
Steel reinforcement cage stretches in the stake holes, and steel reinforcement cage includes steel reinforcement cage main reinforcement 4 and stirrup 16.Auxiliary survey reinforcing bar 15 is located at steel
In muscle cage, auxiliary survey reinforcing bar 15 and 4 equal diameter of steel reinforcement cage main reinforcement, the auxiliary length for surveying reinforcing bar 15 are not less than the 2.5-3 of stake diameter
Times, the auxiliary survey reinforcing bar 15 is cut into two parts, and respectively in one reinforcing rib meter 3 of variable cross-section position bind, the reinforcing rib meter 3 is located at
The variable cross-section position, the pile shaft force value for testing the above position of variable cross-section, the preferably bottom of reinforcing rib meter 3 exist with variable cross-section
On same plane.
The load box 1 is located at the bottom of stake holes, the i.e. bottom of reaming part, and therefore, such device need not pour
Club-footed pile is cut into two parts after concrete to test, i.e. the epimere stake of load box 1 is entire club-footed pile, and hypomere is not present
Stake；The pressure oil pump 14 is located at the outside of stake holes and is connected to load box 1 by oil pipe 12；The upper displacement measuring staff 7 stretches into
It is fixedly connected in the stake holes and with the upper plate of load box 1；The bottom offset measuring staff 9 stretches into the stake holes and and load box
1 lower plate is fixedly connected；Displacement measurement equipment 8 is installed on the top of upper the displacement measuring staff 7 and bottom offset measuring staff 9.
Upper displacement measuring staff 7, load box 1 upper plate and upper displacement measuring staff 7 on displacement measurement equipment 8 between coordinate, use
In the upper displacement for measuring 1 epimere stake of load box, displacement on abbreviation, bottom offset measuring staff 9, load box 1 lower plate and bottom offset
The cooperation between displacement measurement equipment 8 on measuring staff 9, the bottom offset for measuring 1 hypomere stake of load box, simultaneously due to load box 1
There is no hypomere stakes, and therefore, the bottom offset of hypomere stake here in fact refers to pile bottom settlements.
Data acquisition equipment 5 acquires cable 6 by data and is effectively connect with reinforcing rib meter 3 and displacement measurement equipment 8, for connecing
Receive the data information that the reinforcing rib meter 3 and displacement measurement equipment 8 acquire.The data information that data acquisition equipment 5 will also receive
It is sent to processing equipment and carries out data analysis such as computer.
The outside of the upper displacement measuring staff 7 and bottom offset measuring staff 9 is arranged with displacement bar protection pipe 2 and bottom offset bar respectively
Protection pipe 10.Upper displacement bar protection pipe 2 and bottom offset bar protection pipe 10 are used for that mud and concrete is isolated, it is ensured that upper displacement measuring staff
7 and bottom offset measuring staff 9 can freely up and down move.
As a preferred embodiment, based on the considerations of cost and measurement accuracy, auxiliary survey reinforcing bar 15, upper displacement measuring staff 7 and
The quantity of bottom offset measuring staff 9 is two, is evenly arranged, and can also be arranged to other quantity certainly.
After the test, it is contemplated that stake upper and lower displacement causes load box upper and lower bottom plate displacement, produced between load box upper and lower plates
Raw gap, can be by stretching into the slip casting into gap position of grouting behind shaft or drift lining pipe 20 in stake holes.
The method that club-footed pile self-balanced static-load testing is carried out using above-mentioned improved club-footed pile self-balanced static-load testing device,
Including the following contents：
After the concrete poured in stake holes reaches age, start to carry out experimental test to the bearing capacity of live pile body.It is existing
Field experimental test executes《Architecture foundation pile self-balanced static-load testing technical regulation (JGJ/T 403-2017)》Requirement.Experiment uses
Maintained load test (ML-test) hierarchical loading at a slow speed.
(1), experiment Load-unload mode should meet following provisions：
1. load should be classified progress, load box load operation is realized to load box oiling through oil pipe by pressure oil pump, it should
In the process, it should be loaded using equivalent step by step, the capacity value of every grade of load is the 1/10 of load box maximum load amount, and described every grade adds
The capacity value of load is denoted as classification capacity value, wherein 2 times of the desirable classification capacity value of first order load；
2. progress should be also classified by unloading, every grade of unloading measures 2 times of classification capacity value, and equivalent unloading should be classified lotus step by step
2 times of carrying capacity；
3. when Load-unload, should make load transmit uniformly, it is continuous, without impact, and variation of the every grade of load in maintenance process
Amplitude must not exceed ± the 10% of classification capacity value.
(2) it is met the following requirements using maintained load test (ML-test) test procedure at a slow speed：
1. displacement, which is surveyed, reads interval time：To every grade load after displacement carry out survey reading, at every grade load after 5min,
15min, 30min, 45min and 60min survey the displacement of read bit shifting measurement equipment and reinforcing rib meter is read, every after 60min
The displacement and reinforcing rib meter reading that read bit moves measurement equipment are surveyed every 30min.
2. displacement is with respect to stability criterion：Since the 30min after classification load applies, by continuous 3 times every 30min of 1.5h
Displacement observation value calculate, displacement increment is no more than 0.1mm per hour, and continuously occurs twice.
3. loading standard：When change in displacement rate reaches opposite stability criterion, then apply next stage load；
4. unloading standard：When unloading, every grade of load maintains 1h, presses 15min, 30min, 60min respectively and surveys reading displacement
And after reinforcing rib meter reading, you can unload next stage load；After being offloaded to zero, it should survey and read residual displacement amount and reinforcing rib meter reading,
Must not hold time less than being 3h, surveys and read interval time to be that 5min, 30min respectively survey reading primary, survey reading one every 30min later
Secondary residual displacement amount.
(3), there are following situations for the moment in the displacement of the stake of load box epimere or hypomere stake, you can terminates load.
1. under certain grade of load action, the displacement increment of the stake of load box epimere or hypomere stake is greater than or equal to previous stage load
When acting on 5 times of bottom offset increment, and total displacement amount is more than 40mm.
2. under certain grade of load action, the displacement increment of epimere stake or hypomere stake increases more than previous stage load action bottom offset
2 times of amount, and opposite stability criterion has not yet been reached for 24 hours；
3. the maximum experiment loading capacity and load box epimere and hypomere displacement that have reached design requirement reach relatively stable
(convergence) standard.
4. when load~displacement curve of epimere stake or hypomere stake is slow change type, 40mm can be loaded onto by shifting up total amount
~60mm；It can be loaded onto 60~80mm to bottom offset total amount；When end resistance not yet gives full play to, total displacement amount can be loaded onto
More than 80mm.
5. it has been more than load box stroke that load box, which has reached the load limit of load box or the upper and lower section shifting of load box, i.e.,
Load can be terminated.
Test result analysis
Detection data analysis executes specification《Architecture foundation pile self-balanced static-load testing technical regulation (JGJ/T403-2017)》.
(1) processing of detection data should be met the following requirements：
1. the single pair number curve of the relation curve and displacement and loading times of load and displacement should be drawn, can also draw
Other assistant analysis curves；
(2) epimere stake limit loaded value QuuWith hypomere stake limit loaded value QudDetermination should be integrated as follows：
1. determined with the variation characteristic of load according to displacement, for abrupt change type curve, it should take curve that apparent abrupt change occurs
The corresponding payload values of starting point；2. ultimate bearing capacity is determined according to the displacement feature that changes with time, should take displacement with plus
There are the previous stage payload values being obviously bent in the single pair number curve tail portion for carrying the time；3. when there is this regulation the 4.3.4 articles the 1st, 2
When money situation, previous stage payload values are preferably taken；4. can be determined according to displacement to slow change type curve, epimere stake limit loaded value takes pair
Answer displacement be 40mm when load, when epimere stake it is long be more than 40m when, preferably consider the Elastic penetration of pile body；The hypomere stake limit adds
It is the corresponding payload values of 40mm that load value fetch bit, which moves, and the stake of 800mm is greater than or equal to diameter, and the desirable downward displacement of load box is
The corresponding payload values of 0.05D (D is stake end diameter)；5. when not can determine that by the 1st~4 section of this article, preferably it is respectively oriented, downwards
The maximum finder charge of both direction is as epimere stake limit loaded value and hypomere stake limit loaded value.
(3) the suitable equivalency transform of load-displacement curve that self-balanced static-load testing measures is load-position of traditional static test
Move curve (reference《Architecture foundation pile self-balanced static-load testing technical regulation (JGJ/T 403-2017)》).
(4) single pile vertical resistance pressure (pulls out) ultimate bearing capacity, should be calculated according to the following formula：
1. vertical allowable load capacity of single pile is：
Fud=Qud
Fuu=FAxle power
QuFor vertical allowable load capacity of single pile (kN), FuuFor the vertical allowable load capacity of single pile of epimere stake
(kN)；FudFor the vertical allowable load capacity of single pile (kN) of hypomere stake, FAxle powerFor the pile shaft force value of the above position of variable cross-section
(kN)QudFor the final loaded value of actual measurement of load box hypomere stake；W is the sum of dead weight and the impost of load box epimere stake (kN),
Impost should include weight, empty pile cutoff mud or the Cast-in-situ Piles in Sand-filling of the superfilled height of design stake top or more, soil dead weight, level of ground water with
Under should take buoyant weight degree calculate.γ is load box epimere pile side resistance correction factor, is determined according to the type of load upper box part soil：It is glutinous
Property soil, silt take 0.8, sand takes 0.7, and rock takes 1.0, and weighted average is taken when there is different soil.
This improved measurement method proposes the test method of the final loaded value of actual measurement of load box epimere stake, according to load
The final loaded value of actual measurement of case epimere stake is practical to be equal to above base expanding and base expanding stake body variable cross-section position axle power suffered by pile body, utilizes reinforcing bar
Meter measures the final loaded value of actual measurement of load box epimere stake.It is calculated in the following manner：
FReinforcing rib meter i=ki(fii 2-f0i) (1)
In formula：kiFor producer's calibration coefficient (kN/F) of i-th reinforcing bar flowmeter sensor；fiiFor this prison of i-th reinforcing rib meter
Measured frequency reads (Hz)；f0iFor the original frequency modulus (F of i-th reinforcing bar flowmeter sensor0=f0 2)；FReinforcing rib meter iFor reinforcing rib meter axle power
(kN)；For the average value (kN) of the axle power of n reinforcing rib meter；FAxle powerFor the pile shaft force value of the above position of variable cross-section of actual measurement
(kN)；N is the radical of concrete support reinforcing rib meter；AReinforcing barFor reinforcing rib meter sectional area (mm2)；AIt is mixedFor the sectional area of pile concrete
(mm2), EIt is mixedFor modulus of elasticity of concrete (N/mm2)；ESteelFor reinforcing bar elasticity modulus (N/mm2)。
2. vertical ultimate uplift resistance of single pile should be calculated as follows：
In=formula：γ2For by the resistance to plucking frictional resistance conversion coefficient of inspection stake；Pressure-bearing type uplift pile should take 1.0, for bearing type
Uplift pile should be determined by the Comparability test and regional experience of similar conditions according to actual conditions, but cannot be less than 1.1.
(5) single pile vertical resistance pressure (resistance to plucking) characteristic load bearing capacity should be by single pile vertical resistance pressure (resistance to plucking) ultimate bearing capacity
50% value.
The above embodiment is only the preferred embodiment of the present invention, and the scope of protection of the present invention is not limited thereto,
The variation and replacement for any unsubstantiality that those skilled in the art is done on the basis of the present invention belong to institute of the present invention
Claimed range.
Claims (10)
1. a kind of improved club-footed pile self-balanced static-load testing device, it is characterised in that including：
Stake holes, the stake holes includes the non-reaming part of stake holes epimere and positioned at the reaming part of the stake holes hypomere, described
Non- reaming part and reaming part form the upper pile body of club-footed pile and lower pile body, upper pile body after being respectively used to casting concrete
With lower pile body using variable cross-section as interface；
Steel reinforcement cage, the steel reinforcement cage stretch in the stake holes；
Auxiliary survey reinforcing bar, the auxiliary survey reinforcing bar are located in steel reinforcement cage, and the auxiliary survey reinforcing bar blocks simultaneously one steel of bind in variable cross-section position
Muscle meter；
Reinforcing rib meter, the reinforcing rib meter are located at the variable cross-section position；
Load box, the load box are located at the bottom of stake holes, the i.e. bottom of reaming part；
Pressure oil pump, the pressure oil pump are located at the outside of stake holes and are connected to load box by oil pipe；
Upper displacement measuring staff, the upper displacement measuring staff are stretched into the stake holes and are fixedly connected with the upper plate of load box；
Bottom offset measuring staff, the bottom offset measuring staff are stretched into the stake holes and are fixedly connected with the lower plate of load box；
Displacement measurement equipment is installed on the top of upper the displacement measuring staff and bottom offset measuring staff；
Data acquisition equipment, the data information for receiving the reinforcing rib meter and the acquisition of displacement measurement equipment.
2. club-footed pile self-balanced static-load testing device according to claim 1, it is characterised in that：The upper displacement measuring staff and
The outside of bottom offset measuring staff is arranged with displacement bar protection pipe and bottom offset bar protection pipe respectively.
3. club-footed pile self-balanced static-load testing device according to claim 1, it is characterised in that：The auxiliary survey reinforcing bar, on
The quantity of displacement measuring staff and bottom offset measuring staff is two, is evenly arranged.
4. club-footed pile self-balanced static-load testing device according to claim 1, it is characterised in that：The auxiliary survey reinforcing bar and steel
The main reinforcement equal diameter of muscle cage, the auxiliary length for surveying reinforcing bar are not less than 2.5-3 times of pile body stake diameter.
5. a kind of improved club-footed pile self-balanced static-load testing method, it is characterised in that include the following steps：
Test platform is built according to claim 1-4 any one of them club-footed pile self-balanced static-load testing devices；
To age in casting concrete to stake holes；
Step stress test；
Unloading test step by step；
Test data is obtained according to the step stress test and step by step unloading test and test result is analyzed.
6. club-footed pile self-balanced static-load testing method according to claim 5, it is characterised in that：The step stress test
Including：
Equivalent step by step is carried out to load box and loads capacity value, the capacity value of every grade of load is the 1/10- of load box maximum load amount
1/12, the capacity value of every grade of load is classification capacity value；
To every grade load after displacement carry out survey reading, at every grade load after 5min, 15min, 30min, 45min and
60min surveys the displacement that read bit moves measurement equipment, after 60min at interval of 30min survey read bit move measurement equipment displacement and
Reinforcing rib meter is read；
Amplitude of variation of the capacity value of every grade of load in surveying read procedure must not exceed ± the 10% of classification capacity value；
When change in displacement rate when every grade of load reaches opposite stability criterion, then carry out the operation of next stage load.
7. club-footed pile self-balanced static-load testing method according to claim 6, it is characterised in that：The unloading test step by step
Including：
Equivalent step by step is carried out to load box and unloads capacity value, the capacity value of every grade of unloading is 2 times that are classified capacity value；
Every grade of unloading maintains 1h, and survey reading is carried out to the displacement after every grade of unloading in the 1h, and the after being unloaded at every grade
15min, 30min and 60min survey the displacement and reinforcing rib meter reading that read bit moves measurement equipment；
When discharging quantity after unloading is zero, displacement and reinforcing rib meter reading that read bit moves measurement equipment are surveyed, remembers measured displacement amount
The survey read time of residual displacement amount, residual displacement amount is no less than 3h, discharging quantity after unloading be zero after 5min, 30min
Each survey is read once, is surveyed at interval of 30min after 30min and is read a residual displacement amount；
Amplitude of variation of the capacity value of every grade of unloading in surveying read procedure must not exceed ± the 10% of classification capacity value.
8. club-footed pile self-balanced static-load testing method according to claim 7, it is characterised in that：In step stress test
Cheng Zhong occurs under following either case, stops step stress test：
During certain grade of load test, displacement increment or bottom offset increment are not less than during its previous stage load test thereon
5 times of bottom offset increment, and displacement or bottom offset amount are more than 40min thereon；
During certain grade of load test, under displacement increment or bottom offset increment are more than during its previous stage load test thereon
5 times of displacement increment, and opposite stability criterion has not yet been reached in the change in displacement rate during interior this grade of load test for 24 hours；
Reach maximum experiment loading capacity, and tests the change in displacement rate under loading capacity in the maximum and reach opposite stability criterion；
Load box has reached load box maximum load amount or upper displacement and bottom offset amount has reached load box stroke.
9. club-footed pile self-balanced static-load testing method according to claim 8, it is characterised in that：It is described to test result into
Row analysis, including：
Draw the relation curve of the relation curve and displacement and load or unload time of capacity value and displacement；
Determine epimere stake limit loaded value and hypomere stake limit loaded value；
It calculates and obtains vertical allowable load capacity of single pile；
It calculates and obtains vertical ultimate uplift resistance of single pile；
Determine single pile vertical resistance pressure characteristic load bearing capacity and unit for single-pile vertical anti-pulling characteristic load bearing capacity.
10. club-footed pile self-balanced static-load testing method according to claim 9, it is characterised in that：
It is described calculate obtain vertical allowable load capacity of single pile formula be：
Fuu=FAxle power
Wherein, QuFor vertical allowable load capacity of single pile, FuuAnd FudThe respectively single pile vertical resistance pressure of epimere stake and hypomere stake
Ultimate bearing capacity, FAxle powerFor the pile shaft force value of the above position of variable cross-section, QudFor the final loaded value of actual measurement of load box hypomere stake；W
For the sum of the dead weight of load box epimere stake and impost, the impost includes the weight of the superfilled height of stake top or more, sky
Pile cutoff mud or Cast-in-situ Piles in Sand-filling and soil dead weight；γ is load box epimere pile side resistance correction factor, according to load upper box part soil
Type determines；
The pile shaft force value F of the above position of variable cross-sectionAxle powerIt is calculated according to following formula：
FReinforcing rib meter i=ki(fii 2-f0i)
Wherein：kiFor producer's calibration coefficient of i-th reinforcing bar flowmeter sensor；fiiFor i-th reinforcing rib meter this monitoring frequency reading；
f0iFor the original frequency modulus of i-th reinforcing bar flowmeter sensor；FReinforcing rib meter iFor the axle power of i-th reinforcing rib meter；For n reinforcing rib meter
Axle power average value；FAxle powerFor the pile shaft force value of the above position of variable cross-section of actual measurement；N is the root of concrete support reinforcing rib meter
Number；AReinforcing barFor reinforcing rib meter sectional area；AIt is mixedFor the sectional area of pile concrete, EIt is mixedFor modulus of elasticity of concrete；ESteelFor reinforcing bar springform
Amount；
The vertical ultimate uplift resistance of single pile PuCalculation formula be：
=wherein, γ2For by the resistance to plucking frictional resistance conversion coefficient of inspection stake；
The single pile vertical resistance pressure characteristic load bearing capacity is the 50% of single pile vertical resistance pressure bearing capacity；
The unit for single-pile vertical anti-pulling characteristic load bearing capacity is the 50% of unit for single-pile vertical anti-pulling bearing capacity.
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| CN117432010A (en) * | 2023-10-27 | 2024-01-23 | 广州开发区建设工程检测中心有限公司 | Single pile vertical compression bearing capacity detection method and detection structure for enlarged head pile |
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