CN105300813A - Large-scale cyclic simple shear test apparatus - Google Patents

Large-scale cyclic simple shear test apparatus Download PDF

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Publication number
CN105300813A
CN105300813A CN201510809757.XA CN201510809757A CN105300813A CN 105300813 A CN105300813 A CN 105300813A CN 201510809757 A CN201510809757 A CN 201510809757A CN 105300813 A CN105300813 A CN 105300813A
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China
Prior art keywords
oil cylinder
steel loop
simple shear
sample
base
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Pending
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CN201510809757.XA
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Chinese (zh)
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刘方程
王颂
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XIANGTAN CITY HUIFENG EQUIPMENT MANUFACTURING Co Ltd
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XIANGTAN CITY HUIFENG EQUIPMENT MANUFACTURING Co Ltd
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Priority to CN201510809757.XA priority Critical patent/CN105300813A/en
Publication of CN105300813A publication Critical patent/CN105300813A/en
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Abstract

The invention relates to a large-scale cyclic simple shear test apparatus. The apparatus comprises a base. A column and a top beam are arranged on the base. A vertical pressurized oil cylinder and a loading top plate are arranged on the bottom of the top beam. One end of the base is provided with a horizontal counterforce bracket, which is connected to a horizontal pressurized oil cylinder. A loading bottom plate is arranged on the push rod of the horizontal pressurized oil cylinder. A soil bearing box is formed by laminating a plurality of constraining steel rings. The external side of each constraining steel ring is provided with a support lug. The upper surface and lower surface of each support lug are both covered by a layer of rubber gasket. The provided large-scale cyclic simple shear test apparatus can carry out simulation tests of large-size rock samples.

Description

A kind of large-scale Cyclic Simple Shear Testing device
Technical field
The present invention relates to a kind of large-scale cyclic simple shear device for the test of rock soil medium dynamic parameters, relate to ground technical field of measurement and test.
Background technology
Ground is under power cycle load (earthquake, wave, traffic) effect, show hysteresis, nonlinear feature, usually, represent this kinematic behavior by dynamic shear modulus and damping ratio, dynamic shear modulus and damping ratio are the required arguments carrying out Rock And Soil dynamic response analysis.The test method of test soil body kinematic behavior has resonant column test, dynamic triaxial tests and Cyclic Simple Shear Testing.Resonant column test is applicable to test 10 -6~ 10 -4kinematic behavior in range of strain, dynamic triaxial and Cyclic Simple Shear Testing are applicable to test 10 -3~ 10 -1kinematic behavior in range of strain.
Cyclic simple shear equipment in order to when laboratory simulation earthquake shearing wave vertically propagate caused shear stress repeatedly and grow up.Most of many researchers agree to think, Cyclic Simple Shear Testing is the suitable route of bearing (as shown in Figure 1) desirable earthquake stress at test lab simulation soil unit.Therefore, Cyclic Simple Shear Testing is the most suitable test method of test soil body dynamic shear modulus and damping ratio parameter, and it can simulate the stress-strain state of the soil body in place truly, and test findings is more reliable.
The simple shear apparatus that Cyclic Simple Shear Testing is conventional has two kinds, and a kind of flexible formula simple shear apparatus being Norway-Swedish Geotechnical Institute and developing, another kind is the rigidity formula simple shear apparatus of univ cambridge uk's development.The simple shear equipment (being called for short SGI type) that geotechnique research institute of Sweden adopts utilizes folded thin ring repeatedly to place restrictions on the lateral deformation of test specimen, and the simple shear equipment (being called for short NGI type) that geotechnique research institute of Norway adopts then adopts reinforcement rubber membrane.Cambridge type simple shear apparatus then have employed the vertical border of rigidity and rectangular cross section.The simple shear apparatus that Norway's ground is developed, the sample side direction rubber membrane being wound with string is wrapped in, string diameter 0.2mm, pitch 0.5mm.Can prevent lateral expansion after making the sample effect of being under pressure, reach concretion state, after being sheared, shearing can be evenly distributed on sample.The rigidity formula simple shear apparatus of univ cambridge uk's development, sample is square, and during shearing, the side plate of shear direction can rotate, but parallel to each other, keeps specimen length constant.Make the shearing strain of sample even in this way, and lateral expansion does not occur.
Although Cyclic Simple Shear Testing is called " simple shear ", concept is also simple, and the research of many researchers shows, the boundary condition of test specimen in Cyclic Simple Shear Testing is also remarkable.In simple shear sample, what act on the vertical force of upper and lower end face must form a couple with joint efforts to balance the moment of shearing generation, and therefore, vertical normal stress and shear stress are not equally distributed.Seed etc. (1971) first point out that stress distribution uneven in indoor circulation simple shear test instrument may impel test specimen to destroy under lower than the stress required by scene.Prevost and Hoeg(1976) utilize each impact that have studied simple shear test specimen upper and lower end face partial differential boundary slip to homogeneous elasticity analytical technology, find that the distribution of shear stress and normal stress is all subject to the very large interference of this slippage.They report further, owing to there is coupling effect between shearing strain and normal strain in soil, both all can be produced by shear stress or normal stress, and vice versa, therefore, the strain regime usually applying simple scissors can not produce the stress state of simple scissors in soil sample.Shen etc. (1978) have carried out Finite-Element Study to Cyclic Simple Shear Testing, and what discovery NGI type instrument provided is incorrect modulus value.Wright etc. (1978) analyze Cyclic Simple Shear Testing and test, sets forth shearing stress distribution situation that is circular and square surface distance different distance place, test specimen center, find there is significant change to edge scissor stress in the middle part of test specimen, circular test specimen demonstrates larger stress changes than rectangular coupon.In a word, there are some researches show, in conventional Cyclic Simple Shear Testing, there is complicacy and ambiguity in the stress-strain state of sample.
Regular circulation simple shear test is difficult to avoid following defect: 1. specimen size little (maximum gauge≤70mm, highly≤30mm), and soil sample is subject to the impact sampling defect and soil property unevenness, and test findings representativeness is difficult to ensure; 2. because specimen size is little, the stress intrinsic due to test method is concentrated, the impact of Stress non-homogeneity is more remarkable; 3. because specimen size is little, cannot test the great soil group of actual needs research in the engineerings such as coarse-grained soil, reinforced earth, gravel, slag, range of application is restricted.
And large scale Cyclic Simple Shear Testing can improve the defect of stock size Cyclic Simple Shear Testing: 1. first, the increase of specimen size, can reduce the impact of the local defect of sample, improves the representativeness of test findings; 2. the increase of specimen size, can make the impact that in sample, stress is concentrated, stress distribution is uneven reduce; 3. the increase of specimen size, can make soil sample can comprise thick gravel, can carry out straightway testing test, and do not need to carry out scaled down model test to special engineering soil such as coarse-grained soil, reinforced earth, gravel slags, and test findings more directly, reliably; 4. test method, the increase of specimen size, can make test more macroscopicalization, under same Instrument measuring precision, can reduce the lower threshold of minimum strain, the range of application of Extended Cyclic simple shear test.Therefore, large scale Cyclic Simple Shear Testing is a kind of good method and the development trend of the experimental research on dynamic properties of carrying out soil.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, a kind of large-scale Cyclic Simple Shear Testing device is provided.
The present invention is achieved by the following technical programs:
A kind of large-scale Cyclic Simple Shear Testing device, comprise base, column, back timber, vertically pressurize oil cylinder, load top board, horizontal reacting force bracket, level pressurization oil cylinder, add load floor, hold native case;
Described base is vertically provided with two root posts, the top of two root posts is connected to each other by back timber, the bottom of described back timber is provided with the oil cylinder that vertically pressurizes, the push rod of described vertical pressurization oil cylinder is provided with loading top board, described loading top board is provided with guide plate, described guide plate two ends are equipped with vertical slide block, and described column is provided with the vertical guide matched with vertical slide block;
Described base one end is provided with horizontal reacting force bracket, described horizontal reacting force bracket and the level oil cylinder that pressurizes is connected, the push rod of described level pressurization oil cylinder is provided with and adds load floor, described in add load floor bottom cross sliding clock is installed, described base is provided with the horizontal guide rail matched with cross sliding clock;
Describedly hold native case and form by multiple constraint steel loop is mutually stacked, one deck rubber diaphragm is laid at stacked steel loop inwall, to ensure the sealing of sample, the outside of each constraint steel loop is evenly provided with four holder ears tangent with steel loop, described holder ear upper and lower surface respectively posts one deck rubber sheet gasket, in shear history, can there is detrusion in the rubber sheet gasket between adjacent constraint steel loop.
The major function of large-scale Cyclic Simple Shear Testing device of the present invention is: under the effect of external impetus (comprising horizontal direction and vertical direction), side is carried out to test soil sample and limits vertical consolidation, then reciprocal horizontal detrusion is applied to sample, and simulate the volume change of sample in detrusion process.
Principle of work of the present invention is as follows: the native case that holds filling test soil sample is placed on loading top board and adds between load floor by (1).Start the oil cylinder that vertically pressurizes, under oil cylinder effect of vertically pressurizeing, load top board, under the guiding of vertical guide and constraint, vertical displacement occurs, vertical consolidation stress is applied to soil sample; (2) lateral deformation of Sheng soil case to soil sample be made up of stacked constraint steel loop provides constraint, ensures that lateral strain does not occur under vertical stress for it, to simulate the plane strain state in actual soil layer; (3) level pressurization oil cylinder is started, drive adds load floor along horizontal guide rail generation bilateral reciprocation, and it is motionless to load top board horizontal direction maintenance under the constraint of vertical guide, sample is except upper and lower surface is stressed respectively at loading top board and loading contacts baseplate, other no longer by external force, therefore produces along the constant vertical pressure in specimen height direction and horizontal shear force in the sample; (4) sample has the trend that detrusion occurs under the shearing force effect consistent along short transverse, for sample provides the Sheng of boundary constraint soil case while limiting its radial deformation, the generation of sample shear shear deformation is complied with by the relative shear changing of the relative positions between stacked constraint steel loop, thus sample free detrusion can occur, simulate the detrusion state of soil layer in actual soil layer; (5) in shear history, load top board and can not be subjected to displacement in the horizontal direction, but can freely be subjected to displacement at vertical direction, thus the volume change of the soil body in shear history (dilatation or contraction caused by shear) can be simulated.
The present invention has the following advantages:
(1) structural system small axial dimension, do not need outside counter-force: horizontal reacting force is provided by the horizontal reacting force bracket be connected on base, vertical counter-force is provided by the rigid frame (being made up of column and back timber) be connected on base, and system small axial dimension, does not need outer counter power apparatus.
(2) specimen size is large, the prototype test of all kinds of soil can be carried out: in large-scale Cyclic Simple Shear Testing device of the present invention, the maximum gauge of sample can reach 1000mm, specimen height 0 ~ 500mm is adjustable (being realized by the number of plies that stacks changing constraint steel loop), the large dimension specimen circulation shear test of various original state and disturbed soil can be carried out, the coarse-grained soil particularly can not be able to studied conventional test, reinforced earth are tested, and eliminate the scale effect that stock size test apparatus can only do small-scale model test.
(3) boundary condition of Cyclic Simple Shear Testing is strictly met: guarantee that sample can not strain in radial direction by the constraint of stacked steel loop; Guarantee that sample freely detrusion can occur in the horizontal direction by the detrusion of the rubber sheet gasket between stacked steel loop; Guarantee that sample vertical deformation can occur by four vertical guide be installed in rigid posts; Guaranteeing to load top board by the restriction of vertical guide can not occurred level displacement and rotation displacement, guarantees the applying and evenly of shear stress; By the indentation in load plate, increase the friction force between load plate and soil sample, reduce the relative sliding between specimen surface and load plate in shear history.
(4) fill sample simple and convenient: the length of horizontal guide rail is determined through design, be pushed into high order end can obtain enough work spaces by adding load floor when ensureing dress sample, facilitate large-scale soil sample dress sample.
The present invention is unique at home and abroad, fill up the blank of large-scale cyclic simple shear During Geotechnical Tests device, especially large scale, ground sample that shearing strength is high is adapted to, the advantage such as there is compaction capacity is good, water permeability strong, field density more greatly, strictly meets Cyclic Simple Shear Testing boundary condition, easy and simple to handle, test findings is accurate.
Accompanying drawing explanation
Fig. 1 is the stress-strain state schematic diagram of native unit in earthquake.
Fig. 2 is the perspective view of large-scale Cyclic Simple Shear Testing device.
Fig. 3 is the structural representation holding native case.
Fig. 4 is the structural representation of the single constraint steel loop of band holder ear.
In accompanying drawing: 1. base, 2. column, 3. back timber, 4. horizontal reacting force bracket, 5. horizontal guide rail, 6. vertical guide, 7. add load floor, 8. load top board, 9. vertically pressurize oil cylinder, 10. level pressurization oil cylinder, 11. cross sliding clocks, 12. hold native case, 13. holder ears, 14. constraint steel loops, 15. rubber diaphragms, 16. rubber sheet gaskets, 17. guide plates.
Embodiment
As shown in Figure 2, a kind of large-scale Cyclic Simple Shear Testing device, comprises base 1, column 2, back timber 3, vertically pressurization oil cylinder 9, loads top board 8, horizontal reacting force bracket 4, level pressurize oil cylinder 10, add load floor 7, hold native case 12.
Base 1 is welded by shaped steel, base 1 total length about 4m, base 1 overall width about 2.6m.Top base 1 being vertically welded with two root post 2, two root posts 2 is connected to each other by back timber 3, and the connection between back timber 3 and column 2 is for being rigidly connected.Back timber 3 and column 2 all adopt square steel tube or the section steel manufacture such as joist steel or channel-section steel, guarantee that it has enough strength and stiffness during design.
The bottom of back timber 3 is provided with vertically pressurization oil cylinder 9, the push rod of described vertical pressurization oil cylinder 9 is provided with and loads top board 8.Load top board 8 and be provided with two pieces of guide plates 17, the two ends of every block guide plate 17 are equipped with vertical slide block (not shown), and column 2 is provided with the vertical guide 6 matched with vertical slide block.Vertical track is arranged on the tow sides of column 2, each 2 roads, altogether 4 roads on every root post 2, and vertical track adopts high-precision linear track, and length and setting height(from bottom) are determined to ensure that the clear distance loading top board 8 and add load floor 7 is 0 ~ 500mm by design.Load top board 8 and can apply consolidation pressure to sample in oil cylinder 9 effect of vertically pressurizeing, load top board 8 lower surface with sharp tooth indentation, to increase the friction force between itself and sample, the design loading top board 8 guarantees that it has enough strength and stiffness, in loading procedure, only vertical rigid body displacement can occur.
Base 1 one end is provided with horizontal reacting force bracket 4, and described horizontal reacting force bracket 4 is connected with base 1 by high-strength bolt, and the design of bracket guarantees that it has enough strength and stiffness.Horizontal reacting force bracket 4 and the level oil cylinder 10 that pressurizes is connected, the push rod of level pressurization oil cylinder 10 is provided with and adds load floor 7, adding load floor 7 shape is Γ shape, outstanding one end is left screw with connection level pressurization oil cylinder 10, add load floor 7 upper surface band sharp tooth indentation, adding load floor 7 headroom area is 1.0m × 1.0m.The bottom adding load floor 7 is provided with cross sliding clock 11, and described base 1 is provided with the horizontal guide rail 5 matched with cross sliding clock 11; Described horizontal guide rail 5 is laid on base 1, and length is laid along base 1 total length, and horizontal guide rail 5 adopts twice high-precision linear track.
As shown in Figure 3, Figure 4, hold native case 12 and form by multiple constraint steel loop 14 is mutually stacked, lay one deck rubber diaphragm 15 at stacked steel loop inwall, to ensure the sealing of sample.Constraint steel loop 14 diameter is 6mm, and the outside of each constraint steel loop 14 is evenly provided with four holder ears 13 tangent with steel loop.Each holder ear 13 size is about 100 × 50 × 6mm, and holder ear 13 upper and lower surface respectively posts the rubber sheet gasket 16 that a layer thickness is about 2mm, and in shear history, the rubber sheet gasket 16 between adjacent constraint steel loop 14 detrusion can occur.When testing, the native case 12 that holds filling ground sample is placed on and adds on load floor 7.
The present invention is unique at home and abroad, fill up the blank of large-scale cyclic simple shear During Geotechnical Tests device, especially large scale, ground sample that shearing strength is high is adapted to, the advantage such as there is compaction capacity is good, water permeability strong, field density more greatly, strictly meets Cyclic Simple Shear Testing boundary condition, easy and simple to handle, test findings is accurate.
It is to be noted; the present invention is not limited to above-mentioned embodiment; any those skilled in the art, based on any simple modification done above-described embodiment in technical solution of the present invention, Combination application, equivalent variations and modification, all belong in protection scope of the present invention.

Claims (1)

1. a large-scale Cyclic Simple Shear Testing device, comprise base, column, back timber, vertically pressurize oil cylinder, load top board, horizontal reacting force bracket, level pressurization oil cylinder, add load floor, hold native case;
Described base is vertically provided with two root posts, the top of two root posts is connected to each other by back timber, the bottom of described back timber is provided with the oil cylinder that vertically pressurizes, the push rod of described vertical pressurization oil cylinder is provided with loading top board, described loading top board is provided with guide plate, described guide plate two ends are equipped with vertical slide block, and described column is provided with the vertical guide matched with vertical slide block;
Described base one end is provided with horizontal reacting force bracket, described horizontal reacting force bracket and the level oil cylinder that pressurizes is connected, the push rod of described level pressurization oil cylinder is provided with and adds load floor, described in add load floor bottom cross sliding clock is installed, described base is provided with the horizontal guide rail matched with cross sliding clock;
Describedly hold native case and form by multiple constraint steel loop is mutually stacked, one deck rubber diaphragm is laid at stacked steel loop inwall, to ensure the sealing of sample, the outside of each constraint steel loop is evenly provided with four holder ears tangent with steel loop, described holder ear upper and lower surface respectively posts one deck rubber sheet gasket, in shear history, can there is detrusion in the rubber sheet gasket between adjacent constraint steel loop.
CN201510809757.XA 2015-11-21 2015-11-21 Large-scale cyclic simple shear test apparatus Pending CN105300813A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107328664A (en) * 2017-06-28 2017-11-07 同济大学 A kind of self-balancing floating formula shearing loading device tested for rock
CN117433822A (en) * 2023-12-20 2024-01-23 贵州省公路工程集团有限公司 Structural performance evaluation system and method using reinforced concrete bracket as support

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1401987A (en) * 2002-09-28 2003-03-12 清华大学 Circular loading shear apparatus for observing earth and structural member contact face mechanical property

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1401987A (en) * 2002-09-28 2003-03-12 清华大学 Circular loading shear apparatus for observing earth and structural member contact face mechanical property

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
高博等: "《堆叠式剪切模型箱的改进》", 《岩石力学与工程学报》, pages 4021 - 4026 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107328664A (en) * 2017-06-28 2017-11-07 同济大学 A kind of self-balancing floating formula shearing loading device tested for rock
CN107328664B (en) * 2017-06-28 2020-06-26 同济大学 Self-balancing floating type shearing loading device for rock testing
CN117433822A (en) * 2023-12-20 2024-01-23 贵州省公路工程集团有限公司 Structural performance evaluation system and method using reinforced concrete bracket as support
CN117433822B (en) * 2023-12-20 2024-02-13 贵州省公路工程集团有限公司 Structural performance evaluation system and method using reinforced concrete bracket as support

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