CN208501758U - A kind of experimental rig of Collapsible Loess District Long-short Pile Group model - Google Patents

Abstract

The utility model relates to a kind of experimental rig of Collapsible Loess District Long-short Pile Group model, which includes cabinet (1), Model Pile pedestal (2), long Model Pile (3) and short Model Pile (4), stake top power transmission cushion cap (5), pseudo-static test loading system and multiple test data inductive pick-up equipment and respective data receiver.The application of the utility model can overcome field test difficulty and numerical simulation study insufficient, realize different vertical loading conditions, effectively stress condition of the simulation Long-short Pile Group in loess soil layer accurately reflects the corresponding bearer properties of different operating conditions and deformation characteristic.Also, the utility model further comprises that horizontal addload frame etc. realizes the component that horizontal addload test is carried out to Model Pile, compensates for the deficiency of existing the type test, can study bearer properties and deformation characteristic when the horizontal load-bearing of pile body.

Description

A kind of experimental rig of Collapsible Loess District Long-short Pile Group model

Technical field

The utility model relates to Canal in Loess Area pile foundation modeling techniques field more particularly to a kind of collapsible loess The experimental rig of head of district's stub basic model.

Background technique

With the deep implementation of development of the West Regions, China western part Canal in Loess Area super high-rise building engineering is increasing.However Western loess is mostly collapsible loess, and most construction projects can be using pile foundation as super high-rise building under this geological conditions Basis；In big thickness Canal in Loess Area Design of Foundation, for there are two or more layers soil layers can be used as an end in foundation soil The case where supporting course, saturated yielding minimum air velocity discontinuous especially for loess formation saturated yielding, according to the test determination of indoor collapsibility There is obvious waste using the long multi-column pier foundation for penetrating yellow soil horizon of collapsibility of stake in situations such as too conservative.It is analyzed based on Mud Thinner former Reason, using Deformation Control Design principle, mainly controls deformation, stub according to long stake and mainly provides the thinking of bearing capacity, propose Use long-short-pile composite foundation as the basis of Canal in Loess Area super high-rise building, wherein long-short pile is passed through with the pile body of Length discrepancy Upper load is transferred in foundation soil by different supporting courses, and the research about Long-short Pile Group focuses mostly in vertical load Stress deformation characteristic under operative condition, it is less for the research of horizontal Group Piles.

Existing Long-short Pile Group experimental study includes field test and numerical simulation.Since live stake is long, stake diameter all compares Larger, molding is more difficult and costly, so research mostly uses the method for numerical simulation to study the power of Long-short Pile Group Learn performance and deformation characteristic.But since whether the result of numerical simulation meets the actual loading and deformation feelings of Long-short Pile Group Condition will finally be verified by test and live actual effect, so usually passing through under the restriction of the above many factors Laboratory test replaces field test.

Currently, there has been no suitable experimental rigs can more gear to actual circumstances simulation reflection Long-short Pile Group at the scene In " model experiment of composite pile foundation with long and short piles " that actual loading situation, such as the huge China of bear et al. propose, experimental rig includes The square box of ground foundation simulation soil layer sand is accommodated, length Model Pile made of hollow aluminum pipe adds counterweight by reaction frame, lever The loading device of composition, pile strain element and data measurement system.

But, have the disadvantages that (1) test using hollow aluminum pipe as Model Pile, native rigidity ratio (pile body and The relative rigidity of foundation soil) it is bigger than normal, have stress condition and deformation characteristic in test result and pile body Practical Project certain inclined Difference；(2) hardboard auxiliary positioning with holes is directly embedded in sand and used when pile body is embedding, ground foundation simulation soil layer Sand cannot provide stress conditions realistic, for different supporting courses for pile body, and during artificial sand loading very It is difficult to guarantee and the vertical position of pile body is not had an impact, thus it is difficult to ensure that bias does not occur for pile top load during the test, This seriously affects the accuracy of test data；(3) loading device loads pile foundation using cast iron lever, lever and stake The contact position on basis is one flat hinged, and lever does not have lateral confinement device, is easy because basic heavy under load action The bias of load is dropped and is caused.Leading to the factor of load eccentricity during test, there are also such as the inclination of experiment stake pile body, bearing sheets to incline Tiltedly and loading equipemtn causes.

Therefore, how effectively and stress condition of the simulation Long-short Pile Group in loess soil layer that gear to actual circumstances, accurately Reflect corresponding bearer properties and deformation characteristic, is the disaster that puzzlement researcher studies long-short pile for a long time Topic, and this problem how is effectively solved for Long-short Pile Group in the scientific research of Canal in Loess Area, engineer application and right There is important practical significance in the construction and development of Loess Area of Northwest China city super high-rise building.

Utility model content

The technical problem to be solved by the utility model is to provide a kind of Collapsible Loess District Long-short Pile Group models Experimental rig, to realize effective and stress condition of the simulation Long-short Pile Group in loess soil layer that gear to actual circumstances, accurately instead Mirror the purpose of corresponding bearer properties and deformation characteristic.

To solve the above problems, a kind of test of Collapsible Loess District Long-short Pile Group model described in the utility model Device includes:

The cabinet of top end opening, collapsible loess to be inserted；

The Model Pile pedestal of the bottom of box is set；

The long Model Pile and short Model Pile being located at vertically on the Model Pile pedestal when test, the two are iron wire concrete Stake；

It is located at the stake top power transmission cushion cap of model stake top, provides the Pseudo-static test of vertical loading force to the stake top power transmission cushion cap Plate test loading system；

And be uniformly located in model stake body resistance strain gage, be located at model stake top and the stake top power transmission cushion cap Between vertical load sensor, be located at Model Pile and expose to displacement sensor at the collapsible loess discharge position, three It is connected with respective data receiver；

Wherein, the Model Pile pedestal includes long Model Pile pedestal and short Model Pile pedestal, and two kinds of pedestals are by default arrangement Mode is distributed；Each pedestal includes the sleeve that lower end is located at the bottom of box, top end opening, is located at the bullet of the sleeve inner Spring and the stake bottom cushion cap for being located at the spring top；The level of the strength factor of the spring and default foundation soil supporting course is anti- Force coefficient is adapted.

In above-mentioned experimental rig, it is preferred that the experimental rig further includes the horizontal addload that there is pile body to press closer component Frame applies horizontal addload to the horizontal addload frame by horizontal addload mechanism in the pseudo-static test loading system when use Power；Horizontal load sensor is equipped between the horizontal addload frame and the horizontal addload mechanism.

In above-mentioned experimental rig, it is preferred that the pile body on the horizontal addload frame presses closer component in semicircle hook solid.

In above-mentioned experimental rig, it is preferred that the horizontal addload frame includes single pile loading frame, four loading frames or nine Loading frame.

In above-mentioned experimental rig, it is preferred that the long Model Pile and short Model Pile refer to by iron wire as vertical muscle, thin tied silk As tie hoop through iron wire concrete-pile made from filling concrete.

Compared with the prior art, the utility model has the following advantages:

1, mainly there are length Model Pile, Model Pile pedestal, stake top power transmission cushion cap and puppet in the utility model experimental rig Slow test loading system equipment, wherein (1) length Model Pile is the iron wire coagulation according to certain likelihood ratio (scaled) Native stake, close to actual reinforced concrete pile situation；(2) Model Pile pedestal is made of sleeve, spring and stake bottom cushion cap, firstly, It can guarantee verticality of Model Pile when embedding, in experimentation, and then guarantee that bias does not occur for pile top load, secondly, The spring of varying strength coefficient simulates the supporting course of Different Strata, stake in the common soil layer such as analog boulder bed, sandstone, powder soil horizon The stress and deformation of pile body under different operating conditions are held, pile body can be reflected in the various stress conditions of underground with relatively corresponding to reality；(3) pseudo- Size, direction and the position of load, not will cause because of vertical load when slow test loading system guarantees to apply vertical load Application and influence the accuracy of test result.

Therefore, the utility model experimental rig can be effective and gears to actual circumstances simulation Long-short Pile Group in loess soil layer Stress condition, accurately reflect corresponding bearer properties and deformation characteristic, this ensure that the accuracy of test data, into And the accuracy for the conclusion (of pressure testing) that test data analyzer obtained by later use obtains is improved, it is Long-short Pile Group in Canal in Loess Area Application theoretical foundation is provided, while also promoting the theory development of Long-short Pile Group.

2, utility model device further comprises that horizontal addload frame etc. is realized to Model Pile progress horizontal addload test Component compensates for the deficiency of existing the type test, can study bearer properties and deformation characteristic when the horizontal load-bearing of pile body.

Detailed description of the invention

Specific embodiment of the present utility model is described in further detail with reference to the accompanying drawing.

Fig. 1 is three-dimensional structure schematic diagram provided by the embodiment of the utility model.

Fig. 2 is positive schematic view of facade structure provided by the embodiment of the utility model.

Fig. 3 is Model Pile schematic diagram of base structure provided by the embodiment of the utility model.

Fig. 4 is the structural schematic diagram of three kinds of horizontal addload framves provided by the embodiment of the utility model.

In figure: 1-cabinet, 2-Model Pile pedestals, 3-long Model Piles, 4-short Model Piles, 5-stake top power transmission cushion caps, 6-horizontal addload framves, 7-pile bodies press closer component；21-sleeves, 22-springs, 23-stake bottom cushion caps；6a-single pile loading frame, Tetra- loading frames of 6b-, nine loading frames of 6c-.

Specific embodiment

With reference to Fig. 1 ~ 3, the utility model embodiment provides a kind of examination of Collapsible Loess District Long-short Pile Group model Experiment device specifically includes cabinet 1, Model Pile pedestal 2, long Model Pile 3 and short Model Pile 4, stake top power transmission cushion cap 5, Pseudo-static test Plate test loading system, the test data inductive pick-up end being made of resistance strain gage, vertical load sensor and displacement sensor And respective data receiver, each data receiver receive test data and the operation such as are saved, shown.

Cabinet 1 is square case, and top end opening, frame is welded by angle steel, and side wall is organic using organic glass composition It is bolted between glass and angle steel, sealing is wherein filled using expansion glue at gap.Bottom plate is made of steel plate, angle steel Between weld, and bottom plate surrounding uniformly opens up several drainage holes.

Model Pile pedestal 2 divides for long Model Pile pedestal and short Model Pile pedestal, and two kinds of pedestals press default arrangement mode setting It is arranged in 1 bottom of cabinet, such as according to " one is long and the other is short, in quincunx " form.Each pedestal includes that lower end is located at 1 bottom of cabinet Portion, top end opening sleeve 21, the spring 22 being located inside sleeve 21 and the stake bottom cushion cap 23 for being located at the top of spring 22.

Specifically, a connecting plate is welded in 21 bottom of sleeve, and connecting plate is bolted with cabinet 1, easy to disassemble and more It changes；22 bottom end of spring is welded on connection plate top surface, and stake bottom cushion cap 23 is welded on top, for example sleeve 21 is the steel bushing of diameter 70mm Cylinder, stake bottom cushion cap 23 is the groove type steel cushion cap that internal diameter is 70mm, one section of top end opening of the stake bottom cushion cap 23 apart from sleeve 21 Length, stability and verticality after capable of guaranteeing Model Pile insertion in this way.The strength factor of spring 22 is held with default foundation soil The static horizontal loading test of power layer is adapted, and specific value is according to foundation soil water in " technical code for building pile foundation " (JGJ94-2008) Flat resistance coefficient, which calculates, to be determined, the strength factor calculation formula of spring 22 is k=mb (h_p- x), wherein m is that the level of power layer is anti- Force coefficient, b are the equivalent width of stake, h_pFor the buried depth of stake, x is the distance that stake bottom distance calculates point.

Long Model Pile 3 and short Model Pile 4 are iron wire concrete-pile, can be used as vertical muscle, thin tied silk as spiral by iron wire Stirrup through filling concrete be made, such as: according to the length of long and short Model Pile select corresponding length pvc pipe, use diameter for 4, iron wire of 4mm are placed in pvc pipe surrounding, are fixed by thin tied silk interval 30mm, and muscle is indulged using iron wire as Model Pile, Then with thin tied silk interval 25mm around wire mesh cage, thin tied silk is as Model Pile tie hoop, the wire mesh cage diameter of formation 50mm；Then then pvc pipe side is cut through thin tied silk and adhesive tape ring around binding, pvc pipe is reusable, finally by iron Silk cage is placed in concrete perfusion in pvc pipe and forms pile body, shelves 2d and removes pvc pipe later and conserve.

Stake top power transmission cushion cap 5 is thick steel plate, passes through machine driving with the vertical loading mechanism of pseudo-static test loading system It is connected, when test, stake top power transmission cushion cap 5 is located at model stake top, to realize the vertical load test to Model Pile.

Resistance strain gage is uniformly located in model stake body, when test needs to draw in two conducting wires of resistance strain gage, It is connected to static strain testing system, concrete operations refer to the prior art.Vertical load sensor is located at model stake top Between stake top power transmission cushion cap 5, displacement sensor is located at Model Pile and exposes at collapsible loess discharge position.

Above-mentioned resistance strain gage is used to incude and acquire the data of reflection model stake body stress and deformation extent, vertical to carry For lotus sensor for incuding and acquiring the data for reflecting vertical bearing capacity, displacement sensor is heavy for incuding and acquiring reflection stake top Collected data are transmitted to corresponding data receiver by the data of drop amount, three, are used for subsequent analysis.

Wherein, pseudo-static test loading system is common loading system in current pseudo-static test, and pseudo-static test is again Claim Low-cycle Test, refers to the slow test for applying multiple reciprocation cycle effect to structure or structural elements, be to make to tie Structure or structural elements repeat to load and the process of unloading in positive and negative both direction, usually to simulate earthquake when structure back and forth shaking Loading characteristic and deformation characteristics in dynamic.This method is effect when acquiring structural vibration with static(al) method, because referred to herein as pseudo- Slow test or pseudo-static experimental.It include vertical loading mechanism and horizontal addload mechanism in pseudo-static test loading system.

In practical application, data receiver corresponding with resistance strain gage is static strain testing system, is also referred to as Statical strain indicator.Statical strain indicator refers in nondestructive situation, carries out to non electrical quantities such as the deformations of load and material of structure The instrument of electrical measurement.

With reference to Fig. 4, disclosed experimental rig, originally practical in another embodiment of the utility model based on the above embodiment Novel test device further comprises the horizontal addload frame 6 being connected with horizontal addload mechanism in pseudo-static test loading system, There is horizontal addload frame 6 pile body to press closer component 7, and horizontal load sensor is equipped between horizontal addload mechanism, which carries Lotus sensor is used to incude and acquire the data of reflection horizontal bearing amount and sends data to corresponding data receiver, supplies Subsequent analysis uses.

Pile body on horizontal addload frame 6 presses closer component 7 in semicircle hook solid, and the diameter of semicircle crotch is mutually fitted with pile body diameter It answers, it is to be understood that the opening of semicircle crotch is consistent with the direction that horizontal force applies.As needed, horizontal addload frame 6 can be with For the loading frame of corresponding piles with different quantity, than single pile loading frame 6a as shown in Figure 4, four loading frame 6b and nine loading frames 6c.In practical applications, 6 frame body of horizontal addload frame can be formed by reinforcement welding, and then installation requirements uniformly divide semicircle crotch Cloth is welded on frame body.It can be studied based on this by different program simulation single piles, four clump of piles, several different operating conditions of nine clump of piles The bearer properties of the regularity of distribution and pile foundation of pile side friction under soil around pile heterogeneous deformation.

It is accordingly disclosed based on experimental rig disclosed in the various embodiments described above, in the utility model another embodiment a kind of wet The test method for falling into property Canal in Loess Area Long-short Pile Group model, specifically comprises the following steps:

(1) it is evenly arranged resistance strain gage on the pile body of long Model Pile 3 and short Model Pile 4 respectively, then by two kinds of moulds Type stake is respectively placed in corresponding Model Pile pedestal 2.

(2) under the premise of the bulk density and water content of soil around pile and natural collapsible loess are consistent after guaranteeing to fill, toward case Placement in layers collapsible loess material in body 1, and make the exposed segment length of model stake top.

Wherein, collapsible loess material refers to that by collapsible loess, soil around pile obtained is filled out after crushing, sieving, immersion, stirring Material.In the placement in layers collapsible loess material into cabinet 1, controlling compactness is 0.88 ~ 0.93, every layer with a thickness of 8 ~ 10cm. For example, starting paving when filling out, filled out according to every layer of virtual resurfacing thickness 10cm place Min layers, keeps the height of drop of every layer of soil around pile consistent, with Guarantee the uniformity of the soil body, every paving completes into half storey height and flattened, is closely knit, repaves and fill out next layer and flattened, is closely knit. To guarantee the compactness 0.90 of pile peripheral earth during the soil layer of soil around pile paving is filled out, finally by the soil around pile soil body sample into The test of row compacting factor.Soil around pile paving completes finish after Model Pile have exposed a bit of, such as 10cm.

(3) displacement sensor is installed in the revealed section of Model Pile, in model stake top placement vertical load sensor, and Stake top power transmission cushion cap 5 is placed on vertical load sensor.

When practical set, displacement sensor is disposed in Model Pile revealed section, then places vertical load in model stake top Sensor it is levelling can to set sand hill in vertical load sensor and model stake top pad during this, finally on a sensor Place stake top power transmission cushion cap 5 in side.

(4) cabinet 1 is placed on the support frame of pseudo-static test loading system, utilizes pseudo-static test loading system Vertical loading mechanism completes vertical load test, while acquiring corresponding real test data using data receiver, and confession is subsequent Analysis uses.

When actual tests, need first to debug each equipment to ensure all devices normal operation, the cabinet 1 that then will be filled It is moved on the support frame of pseudo-static test loading system and starts to carry out vertical load test, vertical load is hydraulic using digital display Vertical jack adds load, solves not can guarantee load stabilization because of pile foundation settlement after vertically load continues for some time with this The problem of.

Correspondingly, after completing vertical load test using the vertical loading mechanism of pseudo-static test loading system, also The following steps are included:

(5) horizontal addload frame 6 is installed at model stake top upper position, applies 0.7 ~ 0.8 times in model stake top Then ultimate vertical bearing capacity is completed horizontal addload using the horizontal addload mechanism of pseudo-static test loading system and is tested, simultaneously Corresponding real test data is acquired using data receiver, is used for subsequent analysis.

Specifically, after vertical load test, can according to single pile load, four load and nine load respectively into The test of row horizontal addload.By taking four horizontal addload 6b as an example, after the completion of vertical load test, apply 0.8 in model stake top Under the effect of times ultimate vertical bearing capacity, upper position installs four horizontal addload frame 6b at the top of Model Pile, tight with half a month crotch Next point position is leaned in backform type stake top portion, and power is passed to horizontal addload frame by machine driving by level jack.Pseudo-static test load Horizontal load sensor is equipped between the level jack and horizontal addload mechanism of system.

During actual load test, itself is operated for the above vertical load and the load of horizontal addload, in addition to Content mentioned above, other contents refer to the prior art.It but, is quick convenient for those skilled in the art, direct Understand this programme content, some operating process illustrated below.For example, under should meeting during specific load, unloading test Column regulation:

(1) the pile head settlement amount for reading Model Pile is surveyed after every grade of load applies by the 5th, 10,15,30,45,60min, it is later every It is read every 30min primary.

(2) Model Pile settles opposite stability criterion: the pile head settlement amount in every 1h is no more than 0.1mm, and continuously occurs two Secondary (since 30min after every grade of load application, being calculated by the settlement observation value of 3 times or 3 times or more every 30min).

(3) when pile head settlement rate reaches opposite stability criterion, then apply next stage load.

(4) when unloading, every grade of load maintains 1h, and the pile head settlement amount for reading Model Pile is surveyed by the 5th, 15,30,60min；Unloading To after 0, answer the stake top residual settlement amount of measure model stake, hold time as 3h, estimating the time is 5,15,30min, later every 30min, which is surveyed, to be read once.

When there are following situations for the moment, load can be terminated:

(1) under certain grade of load action, the pile head settlement amount of Model Pile is greater than 5 times of settling amount under previous stage load action.

(2) under certain grade of load action, the pile head settlement amount of Model Pile is greater than 2 times of settling amount under previous stage load action, And through stability criterion has not yet been reached for 24 hours.

(3) when, by can determine that the steep drop section of ultimate bearing capacity, and the stake top of Model Pile is total on load-sedimentation (Q-S) curve Settling amount is more than 40mm.

Technical solution provided by the utility model is described in detail above.Specific case pair used herein The principles of the present invention and embodiment are expounded, and the above embodiments are only used to help understand, and this is practical new The method and its core concept of type.It is practical not departing from it should be pointed out that for those skilled in the art Under the premise of new principle, several improvements and modifications can be made to this utility model, these improvement and modification also fall into this In the protection scope of utility model claims.

Claims (5)

1. a kind of experimental rig of Collapsible Loess District Long-short Pile Group model, which is characterized in that the experimental rig includes:

The cabinet (1) of top end opening, collapsible loess to be inserted；

Model Pile pedestal (2) in the cabinet (1) bottom is set；

The long Model Pile (3) and short Model Pile (4), the two being located at vertically on the Model Pile pedestal (2) when test are iron wire Concrete-pile；

It is located at the stake top power transmission cushion cap (5) of model stake top, the puppet for providing vertical loading force to the stake top power transmission cushion cap (5) is quiet Power plate test loading system；

And be uniformly located in model stake body resistance strain gage, be located at model stake top and the stake top power transmission cushion cap (5) Between vertical load sensor, be located at Model Pile and expose to displacement sensor at the collapsible loess discharge position, three It is connected with respective data receiver；

Wherein, the Model Pile pedestal (2) includes long Model Pile pedestal and short Model Pile pedestal, and two kinds of pedestals press default arrangement side Formula distribution；Each pedestal includes the sleeve (21) that lower end is located at the cabinet (1) bottom, top end opening, is located at the sleeve (21) internal spring (22) and the stake bottom cushion cap (23) being located at the top of the spring (22)；The intensity system of the spring (22) Several static horizontal loading tests with default foundation soil supporting course are adapted.

2. experimental rig as described in claim 1, which is characterized in that the experimental rig further includes pressing closer component with pile body (7) horizontal addload frame (6), when use by horizontal addload mechanism in the pseudo-static test loading system to described horizontal plus Carrier (6) applies horizontal loading forces；Horizontal load is equipped between the horizontal addload frame (6) and the horizontal addload mechanism to sense Device.

3. experimental rig as claimed in claim 2, which is characterized in that the pile body on the horizontal addload frame (6) presses closer component It (7) is in semicircle hook solid.

4. experimental rig as claimed in claim 3, which is characterized in that the horizontal addload frame (6) includes single pile loading frame (6a), four loading frames (6b) or nine loading frames (6c).

5. such as the described in any item experimental rigs of Claims 1-4, which is characterized in that the long Model Pile (3) and short Model Pile (4) refer to and be used as vertical muscle, thin tied silk as tie hoop through iron wire concrete-pile made from filling concrete as iron wire.