CN109900406A - Expand soil layer negative friction conversion coefficient measuring device, design method and measurement method - Google Patents
Expand soil layer negative friction conversion coefficient measuring device, design method and measurement method Download PDFInfo
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- 238000012360 testing method Methods 0.000 claims abstract description 44
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- 238000003860 storage Methods 0.000 claims description 24
- 238000006073 displacement reaction Methods 0.000 claims description 21
- 230000003068 static effect Effects 0.000 claims description 17
- 239000003822 epoxy resin Substances 0.000 claims description 13
- 229920000647 polyepoxide Polymers 0.000 claims description 13
- 238000005259 measurement Methods 0.000 claims description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 238000007654 immersion Methods 0.000 claims description 8
- 229910000838 Al alloy Inorganic materials 0.000 claims description 7
- 238000005520 cutting process Methods 0.000 claims description 7
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- 238000002474 experimental method Methods 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 5
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- 244000137852 Petrea volubilis Species 0.000 claims description 4
- 239000003292 glue Substances 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 229910001018 Cast iron Inorganic materials 0.000 claims description 3
- 238000007596 consolidation process Methods 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 238000003892 spreading Methods 0.000 claims description 3
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- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses expansion soil layer negative friction conversion coefficient measuring device, design method and measurement methods, belong to building field, measuring device includes support, steelframe, upper end counterweight indigo plant, cable wire, pulley, upper end pressure sensor, upper end dial gauge, upper end steel plate, floodpipe, expansion soil layer, upper section Model Pile, foil gauge, lower section Model Pile, cabinet, lower end steel plate, lower end pressure sensor, lower end counterweight indigo plant and lower end dial gauge.It is influenced using indoor model test economic performance, strong operability, by complex environment small, there is some superiority in terms of studying the vertical load-bearing stake of single-layer soil, test result can provide reference for practical engineering application.
Description
Technical field
The present invention relates to building fields, more particularly to expansion soil layer negative friction conversion coefficient measuring device, design method
And measurement method.
Background technique
Pile foundation is one of most common base form, is had a wide range of applications in engineering construction field.Single-pile vertical orientation is held
Carry the important topic that power is always domestic and foreign scholars and researcher's concern.Meanwhile as pile foundation engineering is in complex geological condition
Under extensive use, the negative frictional resistance of pile foundation is also increasingly prominent, becomes one of the hot issue of pile foundation research.
Self balanced method negative friction conversion coefficient need to pass through the Comparability test of similar conditions and area according to the actual situation
It is empirically determined.Realized in present engineering when expansion soil layer negative friction conversion coefficient is surveyed higher cost, operability it is not strong, by
Complex environment influences, more difficult measurement.Therefore, it is necessary to design a kind of indoor model test, test result can be Practical Project
Using offer reference.
Summary of the invention
The purpose of the present invention is to provide expansion soil layer negative friction conversion coefficient measuring device, design method and measurement sides
Method solves the difficult technical problem of existing self balanced method negative friction conversion coefficient measurement.
Expand soil layer negative friction conversion coefficient measuring device, including support, steelframe, upper end counterweight indigo plant, cable wire, pulley,
Upper end pressure sensor, upper end dial gauge, upper end steel plate, floodpipe, expansion soil layer, upper section Model Pile, foil gauge, lower section model
Stake, cabinet, lower end steel plate, lower end pressure sensor, lower end counterweight is blue and lower end dial gauge, the steelframe are fixed at support
On, on the pulley fixed setting steelframe, the pile crown of the upper section Model Pile and lower section Model Pile is oppositely arranged in cabinet, institute
Floodpipe is stated to be arranged in cabinet, the cabinet bottom inserts microlith layer, fill out expansion soil layer on microlith layer, the cable wire with it is upper
One end of side pressure force snesor connects, and the other end passes through pulley and connect with upper end counterweight indigo plant, and the upper end pressure sensor is another
End is connect with upper section Model Pile top, and the upper end steel plate is arranged on upper section Model Pile top, the upper end dial gauge setting
On the steel plate of upper end；
The bottom of box is provided with water inlet, and the bottom of box offers aperture, protection is provided through in aperture
Pipe, protection pipe top are connect with lower section Model Pile bottom end, and the cable wire passes through protection pipe and connect with the bottom end of lower section Model Pile, institute
It states lower end pressure sensor and lower end counterweight indigo plant is successively set on cable wire, the bottom of protection pipe is arranged in the lower end Interal fixation
End, the lower end dial gauge are arranged on the steel plate of lower end, and the foil gauge is arranged in upper section Model Pile and lower section Model Pile side
On, the foil gauge is connect by conducting wire with external strain instrument.
Further, the upper section Model Pile and lower section Model Pile are submerged in inside expansion soil layer, the upper segment model
Several foil gauges are equidistantly provided in stake and lower section Model Pile.
Further, several holes are offered on the floodpipe, geotextiles, floodpipe bottom is enclosed on the outside of floodpipe
End is arranged under microlith layer, and the upper end of floodpipe is flowed or blow over and cover completely in expansion soil layer, and the quantity of floodpipe is 2-6 root, spaced set
In cabinet.
Further, the quantity of the water inlet is 2-4, is uniformly arranged in the bottom side of cabinet, water inlet and thin
Rock layers connection.
Further, this programme further includes water service hose and water storage container, and described water service hose one end is connect with water inlet,
The other end protrudes into water storage container, and the water level of water is higher than the height of expansion soil layer in the water storage container.
Further, the upper section Model Pile and lower section Model Pile are all made of outer diameter 25mm, the aluminum alloy hollow of wall thickness 2mm
The depth that pipe production, upper section Model Pile and lower section Model Pile are embedded in expansion soil layer is 670mm, and upper section Model Pile exposes expansion soil layer
Length be 30mm, paste several foil gauges inside upper section Model Pile and lower section Model Pile, foil gauge spacing is uniformly set as
50mm。
The design method of soil layer negative friction conversion coefficient measuring device is expanded, the design method includes the following steps:
Step 1: design upper section Model Pile, lower section Model Pile and floodpipe；
Step 2: setting experiment support, while steelframe is embedded in support, the cabinet of upper end opening is set, and the bottom of box opens up
Experimental port, side open up water inlet, and cabinet is erected on support, and steelframe is located at cabinet two sides；
Step 3: be put into microlith layer toward the bottom of box, floodpipe be inserted vertically into microlith layer, and upper section Model Pile with
Lower section Model Pile is mutually placed in cabinet setting, and the experiment that protection pipe runs through the bottom of box is arranged in lower section Model Pile bottom
Hole；
Step 4: upper end steel plate being fixedly installed at the top of upper section Model Pile, upper end dial gauge, upper end hundred are set on the steel plate of upper end
Divide table to be fixedly connected with wall or fixed object, passes through connection cable wire and upper end pressure sensor one end at the top of upper section Model Pile
Connection, the upper end pressure sensor other end passes through the pulley being arranged on steelframe using cable wire, and upper end is arranged in cable end
Counterweight is blue；
Step 5: the setting of lower section Model Pile bottom end is connect by connecting cable wire with lower end pressure sensor one end, lower end pressure
Lower end counterweight indigo plant is arranged in the sensor other end, and lower end steel plate is arranged in protection bottom of the tube, and lower end dial gauge is arranged on the steel plate of lower end,
Lower end dial gauge is fixedly connected with wall or fixed object.
Step 6: swelled ground layer is laid on toward microlith layer, fixed setting upper end steel plate enters to expand soil layer at the top of upper section Model Pile
Depth is 670mm, and the above length of the soil body is 30mm.
Further, the detailed process of the step 1 are as follows:
Upper section Model Pile and lower section Model Pile use outer diameter 25mm, and the aluminum alloy hollow pipe of wall thickness 2mm makes, by hollow pipe
It is half-and-half splitted using wire cutting method from center, checks and polished notch after the hollow pipe pile body of cutting is intact with fine sandpaper, in pipe
Wall marks foil gauge position, is polished smooth with sand paper, spreading glue, by connecting terminal and strain gauge adhesion to mark, successively
Conducting wire is reserved into cable hole from stake top after welding lead and draws and post label, smear waterproof material epoxy resin in foil gauge and
At its terminals, while the model splitted is bonded with epoxy resin, then apply asphalt mixtures modified by epoxy resin on the pile crown for putting on 2mm wirerope
Pile crown is made positioned on stake top and stake bottom, pile crown of cast iron rouge, and pile crown overall thickness is 15mm, edge of a wing thickness 3mm, outer diameter 25mm,
Internal diameter 20mm is provided with single or double a 2mm threading openings on pile crown, in addition pastes one piece of iron plate in pile crown convenient for measurement pile body position
It moves；
Floodpipe uses the pvc pipe of 16mm, and pvc pipe body uniformly bores aperture, then wraps up 1~2 layer with geotextiles and block hole,
Guarantee that water energy infilters expansion soil layer and is not blocked.
The measurement method of soil layer negative friction conversion coefficient measuring device is expanded, the measurement method includes the following steps:
Step 1: test load and load, displacement observation, toward upper end counterweight indigo plant and lower end counterweight Lan Shangjia counterweight, every grade adds
Carrying is the 1/10 of ultimate load, and the first order is loaded with counterweight basket, then adds counterweight step by step, using method is maintained at a slow speed, often
After adding level-one, payload data is recorded after data stabilization on pressure sensor instrument board, while recording each dial gauge data, is loaded
Time continues 1 hour, in first hour after load, need to carry out five percentage meter readings, time interval every respectively 5,5,10,
10,15,15min, when pile body reaches stable, the difference that front and back reads displacement twice can carry out next stage load when being less than 0.1mm, out
One of existing following situations terminate load: load added by (a) oneself reach test pile ultimate bearing capacity；(b) displacement of next stage load is
5 times of previous stage load-displacement；(c) accumulative displacement is more than 100mm；(d) it is that stable state is not achieved in test pile that test pile, which destroys, is unloaded
Mode: a point Pyatyi unloads, every grade of unloading 10kg, is divided between discharge time one hour, equally to number on pressure sensor instrument board
According to payload data is recorded after stabilization, displacement data reads a data every 30min, all after unloading, every the last time of reading in 3 hours
Read data is included in table by data；
Step 2: data being collected using wireless static strain testing analysis system, is used by deformeter and was adopted every two seconds
The timing acquiring mode for collecting a strain data is transmitted to wireless static strain testing analysis system；
Step 3: using water service hose and water storage container, water service hose one end is connect with water inlet, and the other end protrudes into water storage
In container, the water level of water is higher than the height of expansion soil layer in water storage container, using law of connected vessels, in immersion, keeps water storage
Container water level is higher than expansion soil layer body surface face, until water level remains unchanged in water storage container, shows that expansion soil layer has been satisfied in cabinet
Wirerope need to be used to bind consolidation with, water inlet, prevent leak；
Step 4: repeating step 1, and record corresponding data；
Step 5: being calculated using test pile negative friction conversion coefficient formula, formula are as follows:
Q is that traditional static pressed pile loads limiting value, Q in formulaOn、QUnderLimiting value is loaded for self balanced method upper-lower section,
W is upper section stake self weight, and γ is the resistance to plucking frictional resistance conversion coefficient for examining stake.
Present invention employs above-mentioned technical proposal, the present invention is had following technical effect that
The present invention using indoor model test economic performance, strong operability, influenced by complex environment it is small, in research single layer
There is some superiority in terms of native vertical load-bearing stake, test result can provide reference for practical engineering application, while study expansion
Self balanced method negative friction characteristic in soil is tested by design immersion and two group models that do not soak, in comparative study swelled ground
Self balanced method and traditional static pressure test pile negative friction characteristic obtain soaking in swelled ground different under two kinds of operating conditions of not soaking
Negative friction conversion coefficient, and its reason is analyzed, to realize that building provides good data reference.
Detailed description of the invention
Fig. 1 is the device of the invention sectional view.
Fig. 2 is Model Pile structural schematic diagram of the invention.
Figure label: 1, support；2, steelframe；3, upper end counterweight is blue；4, cable wire；5, pulley；6, upper end pressure sensor；7,
Upper end dial gauge；8, upper end steel plate；9, floodpipe；10, soil layer is expanded；11, upper section Model Pile；12, foil gauge；13, lower die
Type stake；14, cabinet；15, water inlet；16, microlith layer；17, lower end steel plate；18, lower end pressure sensor；19, lower end counterweight is blue；
20, lower end dial gauge；21, gasket；22, protection pipe.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention more comprehensible, referring to the drawings and preferred reality is enumerated
Example is applied, the present invention is described in more detail.However, it is necessary to illustrate, many details listed in specification are only to be
Reader is set to have a thorough explanation to one or more aspects of the present invention, it can also be with even without these specific details
Realize the aspects of the invention.
As shown in Figure 1, expansion soil layer negative friction conversion coefficient measuring device sectional view according to the present invention, including support
1, steelframe 2, upper end counterweight indigo plant 3, cable wire 4, pulley 5, upper end pressure sensor 6, upper end dial gauge 7, upper end steel plate 8, floodpipe
9, soil layer 10, upper section Model Pile 11, foil gauge 12, lower section Model Pile 13, cabinet 14, lower end steel plate 17, lower end pressure is expanded to pass
Sensor 18, lower end counterweight indigo plant 19 and lower end dial gauge 20, the steelframe 2 are fixed on support 1, and the pulley (5) is fixed
It is arranged on steelframe 2, the pile crown of the upper section Model Pile 11 and lower section Model Pile 13 is oppositely arranged in cabinet 14, the floodpipe
9 are arranged in cabinet 14, and 14 bottom of cabinet inserts microlith layer (16), and expansion soil layer 10, the steel are filled out on microlith layer 16
Rope 4 is connect with one end of upper end pressure sensor 6, and the other end passes through pulley 5 and connect with upper end counterweight indigo plant 3, the upper end pressure
6 other end of sensor is connect with 11 top of upper section Model Pile, and the upper end steel plate 8 is arranged on 11 top of upper section Model Pile, institute
Upper end dial gauge 7 is stated to be arranged on upper end steel plate 8；
14 bottom of cabinet is provided with water inlet 15, and 14 bottom of cabinet offers aperture, runs through setting in aperture
There is protection pipe 22,22 top of protection pipe is connect with 13 bottom end of lower section Model Pile, and the cable wire 4 passes through protection pipe 22 and lower section model
The bottom end connection of stake 13, the lower end pressure sensor 18 and lower end counterweight indigo plant 19 are successively set on cable wire 4, the lower end steel
Plate 17 is fixed at the bottom end of protection pipe 22, and the lower end dial gauge 20 is arranged on lower end steel plate 17, the foil gauge 12
It is arranged on 13 side of upper section Model Pile 11 and lower section Model Pile, the foil gauge 12 is connect by conducting wire with external strain instrument.
After cable wire 4 passes through the knotting of upper end steel plate 8 of pile crown double threading openings, passes through single threading opening at stake bottom, connect pressure and pass
Sensor.Protection pipe 22 is PVC protection pipe, and main function is protection cable wire, otherwise cable wire is directly contacted with soil layer, there is friction
Power, load of the load at stake bottom so is no longer pressure sensor measurements, measures pile bottom settlements, stretches out one section convenient for measurement stake
Bottom displacement.Pvc pipe uniformly smears vaseline and reduces itself and soil layer frictional force, and pvc pipe is pacified in steel drum tapping when preventing water leakage soaks
It fills O-shaped coil and removes coil after the completion of immersion when load test.
Upper end pressure sensor 6 measures specific pressure, while upper end dial gauge 7 measures specific displacement situation, immersion
Pipe 9 is arranged more, so that more preferable faster expand expansion soil layer 10, improves the efficiency of experiment.
In the embodiment of the present invention, the upper section Model Pile 11 and lower section Model Pile 13 are submerged in inside expansion soil layer 10,
Several foil gauges 12 are equidistantly provided in the upper section Model Pile 11 and lower section Model Pile 13.
In the embodiment of the present invention, several holes are offered on the floodpipe 9, are enclosed with geotextiles on the outside of floodpipe 9,
9 bottom end of floodpipe is arranged under microlith layer 16, and the upper end of floodpipe 9 is flowed or blow over and cover completely in expansion soil layer 10, and the quantity of floodpipe 9 is 2-
It 6, is set in qually spaced in cabinet 14.
In the embodiment of the present invention, the quantity of the water inlet 15 is 2-4, is uniformly arranged in the bottom side of cabinet 14,
Water inlet 15 is connected to microlith layer 16.
It further include water service hose and water storage container in the embodiment of the present invention, described water service hose one end and water inlet 15 connect
It connects, the other end protrudes into water storage container, and the water level of water is higher than the height of expansion soil layer 10 in the water storage container.
In the embodiment of the present invention, the upper section Model Pile 11 and lower section Model Pile 13 are all made of outer diameter 25mm, wall thickness 2mm's
The depth that the production of aluminum alloy hollow pipe, upper section Model Pile 11 and lower section Model Pile 13 are embedded in expansion soil layer 10 is 670mm, upper section mould
The length that expansion soil layer 10 is exposed in type stake 11 is 30mm, pastes several strains inside upper section Model Pile 11 and lower section Model Pile 13
Piece 12,12 spacing of foil gauge are uniformly set as 50mm.
Self balanced method in swelled ground and traditional static pressure test pile mechanical characteristic are simulated, by submerging test to pile body
Apply expansive force, pile body loaded using multistage loadings method, carries out following calculate finally by date comprision:
(1) swelled ground does not soak under expansion status, test pile Q-s curve, ultimate bearing capacity, pile shaft force, pile body side frictional resistance
Power and negative friction conversion coefficient；
(2) under swelled ground immersion expansion status, stake, native displacement, test pile Q-s curve, ultimate bearing capacity, pile shaft force, stake
Body side friction and negative friction conversion coefficient；
(3) by under two kinds of operating conditions conversion coefficient and specification in silt, cohesive soil, sand value compare and analyze,
Negative friction conversion coefficient value rule in swelled ground is obtained, taking for negative friction conversion coefficient in swelled ground is then determined
Value.
Upper and lower section stake Z1, Z2 of test model stake tradition static pressed pile C1 and self balanced method are all made of outer diameter 25mm, wall thickness
The aluminum alloy hollow pipe of 2mm makes.Pile body embedded depth is 670mm, and the above length of the soil body is 30mm, side at 20mm under stake top
10mm circular hole is opened up, for drawing foil gauge connecting line.
For measurement pile shaft force distribution, a certain number of foil gauges are pasted inside pile body.To ensure that test data is accurate,
In conjunction with the test pile depth of burying and pile body outlet hole site, foil gauge spacing is uniformly set as 50mm, and compile to each foil gauge
Number.
4mm × 5mm connecting terminal and BX120-3AA type strain of the test using the production of Taizhou of Zhejiang Huangyan test equipment factory
Piece.Foil gauge parameter is as follows: grid length × grid width is 3mm × 2mm, 120 ± 0.1 Ω of resistance value, sensitivity coefficient 2.08 ± 1%.For
Foil gauge is pasted, needs using wire cutting method half-and-half to split hollow pipe from center, checks that pile body is intact and is cut with fine sandpaper polishing
Mouthful, it is bonded convenient for pile body, it is as shown in Figure 1 to split pile body.Foil gauge position is marked in inside pipe wall, is polished smooth, is smeared with sand paper
Conducting wire is successively reserved cable hole from stake top after welding lead and drawn by 502 glue by connecting terminal and strain gauge adhesion to mark
Out and label is posted, smear waterproof material epoxy resin at foil gauge and its terminals, while splitted with epoxy resin bonding
Model.Then epoxy resin is applied on the pile crown for putting on 2mm wirerope, pile crown is positioned on stake top and stake bottom.Pile crown is using casting
Iron is made, and pile crown overall thickness is 15mm, edge of a wing thickness 3mm, outer diameter 25mm, and internal diameter 20mm is provided with single or double a 2mm on pile crown and wears
In addition line mouth pastes one piece of iron plate in pile crown convenient for measurement pile body shifting.Stake top is located at for traditional static pressed pile load(ing) point, therefore
After double threading openings that cable wire passes through stake top are knotted with stainless steel clamp, by stake bill kept on file threading opening, hangs counterweight and realize load；And
Self-balancing stake load(ing) point is located at " equalization point ", and cable wire cabling mode is similar with front.
Pile body is uniformly finally filled into epoxy resin, wraps up in one layer of fine sand.Cable wire passes through pile body, connects counterweight by pulley,
Realize multistage loadings.
The model casing tested using high 880mm, the steel drum of diameter 580mm, wall thickness 3mm as this, model casing bottom are added
The circular steel plate for welding 3mm prevents rammed earth from leading to steel drum deformation of bottom, and the hole of two 20mm is bored in bottom, in model casing two sides the bottom of far from
At portion 20mm, two water inlets, the overhanging 40mm of water inlet, convenient for connection water injection pipe is arranged in parallel.
Model casing is placed on the masonry of high 650mm when test, while the angle bar frame of 1750mm is embedded in masonry.Angle steel
Bracket is located at model casing two sides, wide 200mm, long 300mm, and masonry top steelframe also needs to set up diagonal brace.Connection side on angle bar frame
The fixed pulley of steelframe made of steel, 75mm is fixed on steelframe with wirerope, a set of is firmly made system to be formed.
Often add level-one load by LH-S02 sensor precise measurement in test, in LH-PT600 high speed display instrument panel
Show every grade of peak load.
Dial gauge measurement pile body shifting use range for the dial gauge of 50mm, dial gauge with Magnetic gauge stand be fixed on top surface with
On steelframe.
TST3822EN in deformeter test using the production of Jiangsu Stettlen electronic equipment manufacturing Co., Ltd is wirelessly static
Strain testing analysis system is monitored the pile strain sheet data in loading procedure.TST3822EN is wireless, and static strain is surveyed
Examination analysis system is a kind of Engineering-type static resistance deformeter that built-in single-chip microcontroller is controlled, and can directly by WiFi and be calculated
Machine is communicated.Analyze software by the wireless static strain testing of TST3822EN in computer, to the data acquired in real time into
Row simple process and preservation.It is suitble to be widely applied in the various strain stress testing fields such as laboratory, engineering survey to constitute
High speed data sampling and processing system.Multiple integral formula A/D converter is housed on TST3822EN is wireless statical strain indicator, is guaranteed
The best transition speed and precision of user data.Its working principle is that: resistance strain gage is a kind of resistance sensor, it with
The variation of self-resistance reflects mechanical strain that needs measure.Resistance strain gage is formed into measuring bridge, when arm resistance becomes
When change, electric bridge just exports one and it changes the linear voltage of size.By being amplified to the voltage, and to resistance
The sensitivity coefficient of foil gauge is normalized, and the voltage swing of output and actual strain size can be made corresponding.
The design method of soil layer negative friction conversion coefficient measuring device is expanded, the design method includes the following steps:
Step 1: design upper section Model Pile 11, lower section Model Pile 13 and floodpipe 9.
Upper section Model Pile 11 and lower section Model Pile 13 use outer diameter 25mm, and the aluminum alloy hollow pipe of wall thickness 2mm makes, will be empty
Heart pipe is half-and-half splitted from center using wire cutting method, is checked and is polished notch after the hollow pipe pile body of cutting is intact with fine sandpaper,
Inside pipe wall marks foil gauge position, is polished smooth, spreading glue with sand paper, connecting terminal and foil gauge 12 are affixed to label
Conducting wire is successively reserved cable hole from stake top after welding lead and draws and post label by place, is smeared waterproof material epoxy resin and is existed
At foil gauge and its terminals, while the model splitted is bonded with epoxy resin, then apply on the pile crown for putting on 2mm wirerope
Pile crown is made positioned on stake top and stake bottom, pile crown of cast iron epoxy resin, and pile crown overall thickness is 15mm, edge of a wing thickness 3mm, outside
Diameter 25mm, internal diameter 20mm are provided with single or double a 2mm threading openings on pile crown, in addition paste one piece of iron plate in pile crown convenient for measurement
Pile body shifting；
For floodpipe 9 using the pvc pipe of 16mm, pvc pipe body uniformly bores aperture, then wraps up 1~2 layer with geotextiles and block
Hole guarantees that water energy infilters expansion soil layer 10 and is not blocked.
Step 2: setting experiment support 1, while steelframe 2 is embedded in support 1, the cabinet 14 of upper end opening, cabinet 14 are set
Bottom opens up experimental port, and side opens up water inlet 15, and cabinet 14 is erected on support 1, and steelframe 2 is located at 14 two sides of cabinet；
Step 3: being put into microlith layer 16 toward 14 bottom of cabinet, floodpipe 9 is inserted vertically into microlith layer 16, and upper section mould
Type stake 11 and lower section Model Pile 13 are mutually placed in cabinet 14 setting, and 13 bottom of lower section Model Pile setting protection pipe 22 runs through
The experimental port of 14 bottom of cabinet；
Step 4: upper end steel plate 8 is fixedly installed at the top of upper section Model Pile 11, upper end dial gauge 7 is set on upper end steel plate 8, on
End dial gauge 7 is fixedly connected with wall or fixed object, passes through connection cable wire 4 and upper end pressure at the top of upper section Model Pile (11)
The connection of 6 one end of sensor, 6 other end of upper end pressure sensor pass through the pulley 5, Er Qiegang being arranged on steelframe 2 using cable wire 4
Upper end counterweight indigo plant 3 is arranged in 4 end of rope；
Step 5: the setting of 13 bottom end of lower section Model Pile is connect by connecting cable wire 4 with 18 one end of lower end pressure sensor, under
Lower end counterweight indigo plant 19 is arranged in 18 other end of side pressure force snesor, and lower end steel plate 17, lower end dial gauge 20 is arranged in 22 bottom of protection pipe
It is arranged on lower end steel plate 17, lower end dial gauge 20 is fixedly connected with wall or fixed object.
Step 6: swelled ground layer 10 is laid on toward microlith layer 16, fixed setting upper end steel plate 8 enters at the top of upper section Model Pile 11
Expansion 10 depth of soil layer is 670mm, and the above length of the soil body is 30mm.
The measurement method of soil layer negative friction conversion coefficient measuring device is expanded, the measurement method includes the following steps:
Step 1: test load with load, displacement observation, toward upper end counterweight indigo plant 3 and lower end counterweight indigo plant 19 on add counterweight, often
Grade is loaded as the 1/10 of ultimate load, and the first order is loaded with counterweight basket, then adds counterweight step by step, using maintaining at a slow speed
Method often plus after level-one, records payload data after data stabilization on pressure sensor instrument board, while recording each dial gauge number
According to the load time continues 1 hour, in first hour after load, need to carry out five percentage meter readings, time interval is every respectively
5,5,10,10,15,15min, when pile body reaches stable, the difference that front and back reads displacement twice can carry out next stage when being less than 0.1mm
Load, occur one of following situations terminate load: load added by (a) oneself reach test pile ultimate bearing capacity；(b) next stage load
Displacement is 5 times of previous stage load-displacement；(c) accumulative displacement is more than 100mm；(d) it is that stable shape is not achieved in test pile that test pile, which destroys,
State, unloading manner: a point Pyatyi unloads, every grade of unloading 10kg, is divided into one hour between discharge time, equally to pressure sensing instruments and meters
Payload data is recorded on disk after data stabilization, displacement data reads a data every 30min, all after unloading, reads most every 3 hours
Latter secondary data, are included in table for read data；
Step 2: data being collected using wireless static strain testing analysis system, is used by deformeter and was adopted every two seconds
The timing acquiring mode for collecting a strain data is transmitted to wireless static strain testing analysis system；
Step 3: using water service hose and water storage container, water service hose one end is connect with water inlet 15, and the other end protrudes into storage
In water container, the water level of water is higher than the height of expansion soil layer 10 in water storage container, using law of connected vessels, in immersion, keeps
Water storage container water level is higher than expansion 10 body surface face of soil layer, until water level remains unchanged in water storage container, shows expansion in cabinet 14
Soil layer 10 has been saturated, and need to be bound consolidation with wirerope at water inlet 15, be prevented leak；
Step 4: repeating step 1, and record corresponding data；
Step 5: being calculated using test pile negative friction conversion coefficient formula, formula are as follows:
Q is that traditional static pressed pile loads limiting value, Q in formulaOn、QUnderLimiting value is loaded for self balanced method upper-lower section,
W is upper section stake self weight, and γ is the resistance to plucking frictional resistance conversion coefficient for examining stake.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, without departing from the principle of the present invention, it can also make several improvements and retouch, these improvements and modifications are also answered
It is considered as protection scope of the present invention.
Claims (9)
1. expanding soil layer negative friction conversion coefficient measuring device, it is characterised in that: including support (1), steelframe (2), upper end weight
Code blue (3), cable wire (4), pulley (5), upper end pressure sensor (6), upper end dial gauge (7), upper end steel plate (8), floodpipe
(9), soil layer (10), upper section Model Pile (11), foil gauge (12), lower section Model Pile (13), cabinet (14), lower end steel plate are expanded
(17), lower end pressure sensor (18), lower end counterweight blue (19) and lower end dial gauge (20), the steelframe (2) are fixed at
On support (1), on pulley (5) fixed setting steelframe (2), the stake of the upper section Model Pile (11) and lower section Model Pile (13)
Head is oppositely arranged in cabinet (14), and in cabinet (14), cabinet (14) bottom inserts microlith for floodpipe (9) setting
Layer (16) fills out expansion soil layer (10) on microlith layer (16), and the cable wire (4) connect with one end of upper end pressure sensor (6),
The other end passes through pulley (5) and connect with upper end counterweight blue (3), upper end pressure sensor (6) other end and upper section Model Pile
(11) top connects, and the upper end steel plate (8) is arranged on upper section Model Pile (11) top, upper end dial gauge (7) setting
On upper end steel plate (8)；
Cabinet (14) bottom is provided with water inlet (15), and cabinet (14) bottom offers aperture, is run through in aperture and is set
It is equipped with protection pipe (22), protection pipe (22) top is connect with lower section Model Pile (13) bottom end, and the cable wire (4) passes through protection pipe
(22) it is connect with the bottom end of lower section Model Pile (13), the lower end pressure sensor (18) and lower end counterweight blue (19) are set gradually
On cable wire (4), the lower end steel plate (17) is fixed at the bottom end of protection pipe (22), lower end dial gauge (20) setting
On lower end steel plate (17), the foil gauge (12) is arranged in upper section Model Pile (11) and lower section Model Pile (13) side, institute
Foil gauge (12) are stated to connect by conducting wire with external strain instrument.
2. expansion soil layer negative friction conversion coefficient measuring device according to claim 1, it is characterised in that: the upper section
Model Pile (11) and lower section Model Pile (13) are submerged in expansion soil layer (10) inside, the upper section Model Pile (11) and lower die
Several foil gauges (12) are equidistantly provided in type stake (13).
3. expansion soil layer negative friction conversion coefficient measuring device according to claim 1, it is characterised in that: the immersion
Several holes are offered on pipe (9), geotextiles are enclosed on the outside of floodpipe (9), floodpipe (9) bottom end is arranged in microlith layer
(16) under, the upper end of floodpipe (9) is flowed or blow over and cover completely in expansion soil layer (10), and the quantity of floodpipe (9) is 2-6 root, spaced set
In cabinet (14).
4. expansion soil layer negative friction conversion coefficient measuring device according to claim 1, it is characterised in that: the water inlet
The quantity of mouth (15) is 2-4, is uniformly arranged in the bottom side of cabinet (14), water inlet (15) is connected to microlith layer (16).
5. expansion soil layer negative friction conversion coefficient measuring device according to claim 1, it is characterised in that: further include leading to
Water hose and water storage container, described water service hose one end are connect with water inlet (15), and the other end protrudes into water storage container, the storage
The water level of water is higher than the height of expansion soil layer (10) in water container.
6. expansion soil layer negative friction conversion coefficient measuring device according to claim 1, it is characterised in that: the upper section
Model Pile (11) and lower section Model Pile (13) are all made of outer diameter 25mm, the aluminum alloy hollow pipe production of wall thickness 2mm, upper section Model Pile
(11) and lower section Model Pile (13) is embedded in the depth of expansion soil layer (10) as 670mm, and upper section Model Pile (11) exposes expansion soil layer
(10) length is 30mm, several foil gauges (12), strain are pasted inside upper section Model Pile (11) and lower section Model Pile (13)
Piece (12) spacing is uniformly set as 50mm.
7. the design method of soil layer negative friction conversion coefficient measuring device, feature are expanded described in -6 according to claim 1
It is, the design method includes the following steps:
Step 1: design upper section Model Pile (11), lower section Model Pile (13) and floodpipe (9)；
Step 2: setting experiment support (1), while steelframe (2) are embedded in support (1), the cabinet (14) of upper end opening, case are set
Body (14) bottom opens up experimental port, and side opens up water inlet (15), and cabinet (14) is erected on support (1), and steelframe (2) is located at case
Body (14) two sides；
Step 3: being put into microlith layer (16) toward cabinet (14) bottom, floodpipe (9) is inserted vertically into microlith layer (16), and upper
Segment model stake (11) and lower section Model Pile (13) are mutually placed in cabinet (14) setting, the setting of lower section Model Pile (13) bottom
Protection pipe (22) runs through the experimental port of cabinet (14) bottom；
Step 4: upper end steel plate (8) are fixedly installed at the top of upper section Model Pile (11), upper end dial gauge is set on upper end steel plate (8)
(7), upper end dial gauge (7) is fixedly connected with wall or fixed object, passes through connection cable wire (4) at the top of upper section Model Pile (11)
It is connect with upper end pressure sensor (6) one end, pressure sensor (6) other end in upper end is passed through using cable wire (4) to be arranged in steelframe
(2) pulley (5) on, and cable wire (4) end setting upper end counterweight is blue (3)；
Step 5: the setting of lower section Model Pile (13) bottom end is connect by connecting cable wire (4) with lower end pressure sensor (18) one end,
Lower end counterweight indigo plant (19) is arranged in pressure sensor (18) other end in lower end, and lower end steel plate (17) are arranged in protection pipe (22) bottom, under
Dial gauge (20) are held to be arranged on lower end steel plate (17), lower end dial gauge (20) is fixedly connected with wall or fixed object.
Step 6: being laid with swelled ground layer (10) on toward microlith layer (16), upper end steel plate is fixedly installed at the top of upper section Model Pile (11)
(8) entering to expand soil layer (10) depth is 670mm, and the above length of the soil body is 30mm.
8. the design method of expansion soil layer negative friction conversion coefficient measuring device according to claim 7, feature exist
In the detailed process of the step 1 are as follows:
Upper section Model Pile (11) and lower section Model Pile (13) use outer diameter 25mm, and the aluminum alloy hollow pipe of wall thickness 2mm makes, will be empty
Heart pipe is half-and-half splitted from center using wire cutting method, is checked and is polished notch after the hollow pipe pile body of cutting is intact with fine sandpaper,
Inside pipe wall marks foil gauge position, is polished smooth, spreading glue with sand paper, connecting terminal and foil gauge (12) are affixed to label
Conducting wire is successively reserved cable hole from stake top after welding lead and draws and post label by place, is smeared waterproof material epoxy resin and is existed
At foil gauge and its terminals, while the model splitted is bonded with epoxy resin, then apply on the pile crown for putting on 2mm wirerope
Pile crown is made positioned on stake top and stake bottom, pile crown of cast iron epoxy resin, and pile crown overall thickness is 15mm, edge of a wing thickness 3mm, outside
Diameter 25mm, internal diameter 20mm are provided with single or double a 2mm threading openings on pile crown, in addition paste one piece of iron plate in pile crown convenient for measurement
Pile body shifting；
Floodpipe (9) uses the pvc pipe of 16mm, and pvc pipe body uniformly bores aperture, then wraps up 1~2 layer with geotextiles and block hole,
Guarantee that water energy infilters expansion soil layer (10) and is not blocked.
9. the measurement method of soil layer negative friction conversion coefficient measuring device, feature are expanded described in -6 according to claim 1
It is, the measurement method includes the following steps:
Step 1: test load and load, displacement observation, toward upper end counterweight blue (3) and lower end counterweight indigo plant (19) on add counterweight, often
Grade is loaded as the 1/10 of ultimate load, and the first order is loaded with counterweight basket, then adds counterweight step by step, using maintaining at a slow speed
Method often plus after level-one, records payload data after data stabilization on pressure sensor instrument board, while recording each dial gauge number
According to the load time continues 1 hour, in first hour after load, need to carry out five percentage meter readings, time interval is every respectively
5,5,10,10,15,15min, when pile body reaches stable, the difference that front and back reads displacement twice can carry out next stage when being less than 0.1mm
Load, occur one of following situations terminate load: load added by (a) oneself reach test pile ultimate bearing capacity；(b) next stage load
Displacement is 5 times of previous stage load-displacement；(c) accumulative displacement is more than 100mm；(d) it is that stable shape is not achieved in test pile that test pile, which destroys,
State, unloading manner: a point Pyatyi unloads, every grade of unloading 10kg, is divided into one hour between discharge time, equally to pressure sensing instruments and meters
Payload data is recorded on disk after data stabilization, displacement data reads a data every 30min, all after unloading, reads most every 3 hours
Latter secondary data, are included in table for read data；
Step 2: data being collected using wireless static strain testing analysis system, is used by deformeter and acquired one every two seconds
The timing acquiring mode of secondary strain data is transmitted to wireless static strain testing analysis system；
Step 3: using water service hose and water storage container, water service hose one end is connect with water inlet (15), and the other end protrudes into water storage
In container, the water level of water is higher than the height of expansion soil layer (10) in water storage container, using law of connected vessels, in immersion, keeps
Water storage container water level is higher than expansion soil layer (10) body surface face, until water level remains unchanged in water storage container, shows in cabinet (14)
Expansion soil layer (10) has been saturated, and need to be bound consolidation with wirerope at water inlet (15), be prevented leak；
Step 4: repeating step 1, and record corresponding data；
Step 5: being calculated using test pile negative friction conversion coefficient formula, formula are as follows:
Q is that traditional static pressed pile loads limiting value, Q in formulaOn、QUnderFor self balanced method upper-lower section load limiting value, W be upper section stake from
Weight, γ are the resistance to plucking frictional resistance conversion coefficient for examining stake.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910198670.1A CN109900406B (en) | 2019-03-15 | Device for measuring negative friction conversion coefficient of expansive soil layer, design method and measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910198670.1A CN109900406B (en) | 2019-03-15 | Device for measuring negative friction conversion coefficient of expansive soil layer, design method and measurement method |
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| CN109900406B CN109900406B (en) | 2024-05-17 |
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| CN114910198A (en) * | 2022-03-28 | 2022-08-16 | 中交第二航务工程局有限公司 | Fiber grating side friction resistance sensor and calibration device and method |
| CN115478568A (en) * | 2022-08-22 | 2022-12-16 | 宁波大学 | Experimental apparatus is cuted to drainage stake soil contact surface |
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