CN105910909B - The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores - Google Patents
The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores Download PDFInfo
- Publication number
- CN105910909B CN105910909B CN201610186531.3A CN201610186531A CN105910909B CN 105910909 B CN105910909 B CN 105910909B CN 201610186531 A CN201610186531 A CN 201610186531A CN 105910909 B CN105910909 B CN 105910909B
- Authority
- CN
- China
- Prior art keywords
- rock
- tensile strength
- rock sample
- test
- tensile
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0003—Steady
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/003—Generation of the force
- G01N2203/0042—Pneumatic or hydraulic means
- G01N2203/0048—Hydraulic means
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a kind of double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores.The testing machine includes three loading system, pressure monitoring and data collection system, loading frame and sample clamping system parts.The loading system includes upper platen, bulb, ball seat, tower-shaped spring, flexural pivot end cap, oil cylinder, pressing disc, guide sleeve and guide plate.The pressure monitoring and data collection system include sensor and data acquisition subsystem, pressure on the number display screen, monitoring pressure gauge and laptop data acquisition subsystem.The loading frame and sample clamping system include variable diameters rock sample interior annular platen, variable diameters rock sample outer toroid platen, lower beam, column, column fixed ring and upper beam.The testing machine can monitor and record the entire test process of rock sample tensile failure, and tensile strength quantitative values when quickly determining rocks in direct tension, and test philosophy and process precise and reliable have filled up the blank of this domestic research field.
Description
Technical field
The invention belongs to geological prospecting measuring technique and apparatus fields, and in particular to a kind of double annulus of more diameter cores are direct
Stretch Tensile Strength of Rock testing machine.
Background technique
The tensile strength of rock is an important mechanical index of rock material, in rock mechanics theory research and rock mass work
Irreplaceable role is suffered from journey practical application.Tensile failure is still the chief destructive shape of engineering rock mass and nature rock mass
One of formula, and since the tensile strength of rock material is far below compression strength, cause country rock always to break since Tension Stress Zone
It splits.For from physical significance, Tensile Strength of Rock refers to the limit stress for causing cohesiveness to fail, general only to consider that single shaft is anti-
Tensile strength.Cai Meifeng etc. (2002) is to Rock Under Uniaxial Compression tensile strength is defined as: rock reaches destruction in the case where being uniaxially stretched effect
When the maximum tension stress that can bear.Because of the particularity of rock material, the measurement result of Tensile Strength of Rock often will appear compared with
The simplification of big discreteness and Tensile Strength of Rock calculating formula can also allow measurement result and practical tensile strength values to generate deviation.
Although the tensile strength of rock and/or rock mass can dominate many destructive process, due to measurement Tensile Strength of Rock very it is cumbersome and
Difficulty, therefore can all ignore accurate measurement and estimation to rock and rock mass tensile strength in many engineering practices.It is main at present
Tensile Strength of Rock measuring method can be divided into two class of uniaxial direct tensile method and indirect pulling method.Wherein uniaxial direct tensile method includes straight
To pulling method, the direct simple tension method of amendment, indirect pulling method includes Brazilian split the law, three-point bending method, four-point bending for order
Method method.The basic principle and advantage and disadvantage of these methods will be discussed respectively according to uniaxial direct tensile method and indirect pulling method below.
1, direct tensile test
The tensile strength principle and rock tension of direct tensile test method (Direct pull test, DPT) survey rock are strong
The description for spending definition is the most close, and measurement result is directly effective.1978 International Society of Rock Mechanics (ISRM) as survey
One of the recommended method of Tensile Strength of Rock is tried, American Society Testing and Materials (ASTM) also tried this uniaxial direct tensile in 2008
The code test that proved recipe method is measured as Tensile Strength of Rock.Direct one directional tensile test and metal material stretching test are similar
Seemingly, test specimen and fixture principle are as shown in Figure 1.Test specimen is placed on testing machine and is axially stretched, stress when test specimen is pulled off
Value is the unidirectional tensile strength (abbreviation tensile strength) of rock.By the ratio of height to diameter of rock pillar in direct tensile test in relevant criterion
It is appointed as 2.0-3.0.The key of uniaxial direct tensile method test is: first is that must have enough cohesive forces between rock sample and fixture
Or frictional force；Second is that the pulling force applied must be concentric with rock sample.Otherwise, it just will appear rock sample and fixture be de-
Phenomena such as falling, or due to eccentric load, the destruction section of test specimen is made to be not orthogonal to the axle center of rock sample causes test to lose
It loses.Due to rock category fragile material, it is relatively time consuming to be processed into " dog bone shape " or " cylindrical body " sample, machining yield
Also low, while being difficult for the pulling force of fixture to be overlapped with the holding of the axis of test specimen.When measuring Tensile Strength of Rock with needing larger samples,
Other more general tensile strength measurement methods are preferably combined, only carry out the direct tensile test of few sample as a comparative reference, with
Verify the result error situation of other test methods.
Force-bearing situation under common rocks in direct tension experimental rig and rock sample loading method can be used as Fig. 1 (a) (b)
The Tensile Strength of Rock calculation formula under the force modes is provided in expression, ISRM (1978) and ASTM (2008) standard are as follows:
σt=Fa/A×10(MPa) (1)
In formula: FaIt is the pulling force (kN) when test specimen is pulled off；A is test specimen cross-sectional area (cm2)。
When carrying out direct tensile tests, while it also being applied with confining pressure to test specimen, then Hoek (1964) and Brace
(1964) the Tensile Strength of Rock calculation formula under the dog bone shape test specimen of the suggestion force modes are as follows:
In formula: FaIt is axial application load, A1It is the diameter at the narrow place of rock pillar, A2It is end diameter, P is confining pressure.
As previously described, because it is extremely difficult to apply the pulling force coaxial with rock sample, therefore some scientists propose conversion equipment
Convert the pressure to pulling force, as shown in Fig. 2, due to be experimental rig change, therefore the rock tension under the force modes is strong
Spending calculation formula, still such as formula (1) is shown.Luong (1986,1988) is from the angle of rock sample, it was also proposed that one kind
It is the rock sample uniaxial direct tensile experimental program of pulling force by pressure conversion, but subsequent research work is considerably less, does not form maturation
Experiment parameter and experimental facilities, really become a kind of experimental program and experimental facilities for widely receiving and approving, therefore still
So need further developmental research.
2, Indirect Tensile Tests
2.1 Brazilian diametral compression tests
Brazilian diametral compression test is also known as disk diametral compression test (Brazilian test), because being proposed by Brazilian Hondros
Tensile strength measuring method, therefore Brazilian test method is often made by person, is used to test the tensile strength of rock fragile materials
There is more than 40 years history, and has at home and abroad been widely used in many engineering fields.International Rock power in 1978
As one of the recommended method of test Tensile Strength of Rock, it has been put into U.S. ASTM, Britain BS, the world for association
In iso standard, this method is formally included in national standard and professional standard by 1999 and China in 2001.Brazilian test is
It is horizontally placed between the bearing plate of press machine, and processed discoid (or square plate) test specimen in the upper and lower pressure-bearing of test specimen
A hard steel wire or other materials are respectively placed between plate as filler strip, then load makes test specimen be pressurized, and test specimen radially produces
Raw pulling damage, in the hope of its tensile strength.The effect of filler strip is the pressure of application to be become line load, and it is vertical to generate test specimen
Stretching force in upper and lower load action direction.Therefore, filler strip must be located at and test specimen vertical symmetry axial plane.Disk diametral compression test dress
It sets as shown in Figure 3.
The shape and loading method of experimental rig and rock sample of the people when carrying out Brazilian diametral compression test to Brazil's splitting into
Further investigation is gone.Main Brazilian test device and rock sample style of loading are as follows: be not added filler strip test rock sample (have it is cylindric,
Circular, processing platform shape)；The rock sample (arc fixture, angular loads fixture, thick filler strip, thin filler strip) of cushioning item or fixture.No
The force-bearing situation of same test method rock sample is also not quite similar, and obtained test result also has certain otherness.
The basic principle of Brazilian split the law is the Solution of Elasticity Theory compressed radially in pairs based on disk.Classical disk is split
Tensile Strength of Rock test is split, is testing scheme as defined in International Society of Rock Mechanics recommended method (ISRM, 1978), test specimen is split
The tension direction of broken face should be consistent with the Impact direction of Rock Under Uniaxial Compression compression test, and cylinder test specimen diameter is preferably 48~54mm,
The thickness of test specimen is preferably 0.5~1.0 times of diameter, and should be greater than 10 times of rock the largest particles.Rock is calculated according to the following formula
Tensile strength:
In formula: P is the peak load (N) for acting on sample, and d is disk diameter (mm), and t is disc thickness (mm).
By comparing various disk tensile splitting strength values it is found that the surveyed tensile strength values fluctuation of disk split the law is larger,
By the sequence tensile strength values of sedimentary rock, metamorphic rock, granite in gradually big trend, the compression strength size of this and each rocks
Also corresponding, meet the empirical law that tensile strength and compression strength in pertinent literature are in certain corresponding relationship.For same class
Rock, since (rock sample machining shape, rock sample dry and wet condition, clamp-shaped, load are dynamic for the artificial influence factor of disk diametral compression test
Power mode etc.) very much, so that the test result of measurement is also had very big difference, and slightly biased compared with the practical tensile strength values of rock
It is small.Therefore the tensile strength values of Practical Project rock mass cannot be equivalent to completely according to the test result of disk split the law.
Disk diametral compression test is due to the practicability and simplicity compared with direct tensile test test Tensile Strength of Rock, by me
The Standard for test methods of engineering rock masses (GB/T50266-99) of state, hydraulic and hydroelectric engineering rock test regulation (SL264-2001)
It is defined as the Tensile Strength of Rock test of standard.The hypothesis of disk (or annulus) diametral compression test is that rock is linear elasticity and homogeneous
Material is based on Elasticity Theory.Test itself is simpler, but stress state is very complicated.In addition to this, test result also by
The influence of many factors, the material and size of filler strip have an impact to the test of tensile strength；Load Contact Condition is to test result
Also have an impact；The failure mode of the different lithologies sample such as hard rock and soft rock and bedded rock is different, need to distinguish selection loading method；
The mechanical model of Brazilian tensile splitting strength test determines that many scholars attempt to have obtained Brazilian test rock there are many more querying
Calculation formula is sought in the amendment of tensile strength.Compare diametral compression test and direct tensile test as a result, the Brazilian tension intensity of rock and straight
Connecing (axial direction) tensile strength numerically often has bigger difference, and diametral compression test can't replace direct tensile test completely.
The GENERAL EXPERIMENTATION for measuring Tensile Strength of Rock is Brazilian diametral compression test, but due to Brazilian test result and directly
The result of (axial direction) tension test has difference, and the direct tensile test for carrying out few sample should be aided with while carrying out Brazilian test
To be verified to obtained experimental result, preferably to ensure test result accuracy, reliability.
2.2 bending tensile test
Bend test (Bending tests) is generally used to testing elastic modulus in rock mechanics experiment and rock is anti-
Tensile strength.It makes the lower edge of beam generate the effect of pure tensile stress using the method for 3 points or 4 points loads of structural test central sill
And rock sample is made to produce fracture the principle of destruction, the tensile strength values of rock are found out indirectly.American Society Testing and Materials
(ASTM) bending tensile test is classified as to the code test of measurement Tensile Strength of Rock.The form of bending tensile test mainly has three
Point bending tensile test, four-point bending tension test.Test mainly by the way that rock is processed into the strip of rectangular cross section after, set
Loaded on special support, test specimen beam lower edge Tensile and be broken, main experimental rig and test process such as Fig. 5,
Shown in Fig. 6.
Four-point bending tension test calculation of Tensile Strength formula are as follows:
In formula: L is supporting-point spacing (cm)；H is that test specimen is high (cm)；B is that test specimen is wide (cm).
Three-point bending tension test calculation of Tensile Strength formula are as follows:
In formula: L is supporting-point spacing (cm)；H is that test specimen is high (cm)；B is that test specimen is wide (cm).
The mechanical model of bending tensile test is built upon on following 4 basic assumptions basis: the 1. section of beam
Strictly remain plane；2. material is homogeneous, Hooke's law is obeyed；3. bending occurs in the plane of symmetry of beam；4. stretch and
The stress-strain behavior of compression is identical.For rock, the 4th is assumed that there are biggish difference with the characteristic of rock, therefore
There is also certain deviations for the tensile strength acquired using bending resistance method, and the processing of test specimen is also more than uniaxial direct tensile method trouble.
Currently to bending tensile test carry out it is less, test data is also very limited, the method measurement tensile strength values compared with
Greatly.Compared with the test of uniaxial direct tensile method, generally practical tensile strength values are bigger than normal for measurement result, the reference value of test result
Smaller, recommendation of such test generally not as Tensile Strength of Rock measurement is tested.
Bending tensile test has been studied and has been used by many scholars as one of Tensile Strength of Rock test method, the test
The rock sample of method is strip and block, and test process is succinct, direct.But it asks calculation formula to have more hypotheses, such as " stretches
It is identical with the stress-strain behavior of compression " it is not inconsistent its mechanical property at all for rock, and the processing of test specimen is also more than straight
Connect pulling method trouble.Tensile strength obtained by three-point bending tension test is bigger than normal than direct tensile strength, analysis the main reason is that
The factor of tensile strength is influenced in three-point bending method other than span, height and thickness, it is the length and width of pre-existing crack, preset
All there is large effect in the position etc. of crackle to tensile strength.For the identical rock sample of a batch, in the indiscriminate situation of rock sample itself
Its tensile strength test value and test loading speed also have very big relationship, such as increase an amount in loading speed for granite
When grade, tensile strength about increases by 10%.Furthermore have scholar to query, the rupture mechanism of three-point bending is stretching, compression shear pair
Rupture mechanism is weighed, rock property is converted to Discontinuous transmission by continuous media in rupture process, and in calculation of Tensile Strength formula
In, these influence factors are not considered.To obtain more accurate tensile strength, calculation formula also needs further
Amendment, research.
Many scholars have attempted the various indirect tensile strength measurement methods that can substitute direct tensile test of searching, usually
The maximum tensile stress calculated when rock sample destroys can be sought using continuity mechanics, and assumes that sample meets linear-elastic behavior and Dual module mould
Type.Furthermore rock material properties in tensional state is usually brittleness, only tensile fracture occurs at Tensile stress.Nothing
By being direct tensile test or Indirect Tensile Tests measurement result reliability will receive the scale effect and size effect of test specimen
The influence answered, the former is influenced by particle scale and sample dimensions relative size, and the latter is according to the situation of the volume size of test specimen
Also suffer from the influence that rock material has defect problem.Furthermore the presence of stress gradient effect also will affect Indirect Tensile Tests
Test result.This also explains stress gradients will lead to three-point bending and four-point bending test than straight with the presence of fault in material
The result for connecing tension test is bigger than normal.Smaller size smaller rock sample is also for measuring tensile strength in the presence of big stress gradient, to reduce
Rock own material defect bring influences.Various main Tensile Strength of Rock measurement method advantage and disadvantage are as outlined in table 1
It is described.
The measurement test of 1 main rock tensile strength of table is compared
As previously mentioned, current tensile strength test method causes to test accordingly dry due to loading the variation of contact conditions
Disturb it is also larger, and exist test hypotheses, the approximate error that mechanical model is chosen, numerical value calculate in many influences such as error
Factor fails to be formed one and is widely recognized as and reference so that these method testing results show randomness, unstability
Tensile Strength of Rock testing standard.In view of the foregoing, it is highly desirable to develop new uniaxial direct tensile Tensile Strength of Rock examination
Test equipment.
Summary of the invention
In order to solve the problems, such as that existing tensile strength test method and apparatus exists, the present invention provides a kind of more diameter rocks
The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of core.The experimental machine can be realized more diameter core tensile strength it is easy,
It quickly and precisely determines, while meeting following some specific performance indexs:
(1) tensile strength that can meet more diameter cores acquired in geological prospecting quickly measures, and core diameter is referring to " rock
Geotechnological journey geotechnical investigation code, DGJ08-37-2012 "；
(2) precision of tensile strength experimental machine test pressure sensor is better than 0.1%；
(3) on-load pressure pump is able to satisfy various different-diameters and the tensile strength measurement of lithology core requires, maximum output
Pressure is not less than 50MPa；
(4) laboratory apparatus is equipped with digital display screen, while the real-time Transmission and record of data acquisition may be implemented, and adopts with computer
It is transmitted with R232 interface or USB interface.
To realize above-mentioned target, the invention adopts the following technical scheme:
1, mechanical model and principle
Present invention is primarily aimed at the complete cores obtained using geological prospecting (or geotechnical engineering investigation) quickly to carry out
Tensile Strength of Rock measurement.The core of acquirement is cut into suitable length first, the length for being typically chosen core should be core
2 times of diameter, core length are at least 1.5 times of core diameter, core both ends are polished.By the core of well cutting from top surface and
Bottom surface, which respectively covers, bores two coaxial with core and different-diameter annulus cylinders.Finally the core prepared is placed on loading frame, it can
Apply active load from top-loaded disk or bottom-loaded ring with selection, schematic diagram is as shown in Figure 7.
After experiment starts, to an xial feed is applied at the top of rock sample, the support ring of rock sample bottom can apply one to rock sample
A counter-force, as xial feed constantly increases, can center drum position in the middle part of rock sample generate tensile region, as dark in Fig. 8 (a)
Shown in color dash area.Continue to increase xial feed, last rock sample occurs tensioning in anticipation rupture location as shown in Figure 7 and breaks
It is bad, it is destroyed from starting to be loaded into rock sample, what the stress distribution that rock sample destroys position can be rough be divided into three ranks
Section, before destruction, when destroying and after destroying, as shown in Fig. 8 (b), (c), (d), (e).Prerupture axial stress (σy) distribution is such as
Shown in Fig. 8 (c), correspond to the A point in Fig. 8 (b), at this time since the edge for being applied to center drum of xial feed generates
Stress is concentrated, and stress distribution shows as edge stress and concentrates position stress level high, and then stress is not far from stress concentration portion position
It is disconnected to reduce.As xial feed is continuously increased, stress concentration region constantly expands, the axial stress (σ on center drum sectiony) point
Pulling damage occurs for the region that cloth gradually tends to uniformly reach at first Tensile Strength of Rock, and stress starts to reduce, such as Fig. 8 (d) institute
Show, corresponds to the B point in Fig. 8 (b).After rock sample destroys, axial stress (σy) magnitude decreases, pulling damage occurs
The stress level in region goes to zero, and as shown in Fig. 8 (e), corresponds to the C point in Fig. 8 (b).From starting to be loaded into the complete of rock sample
It destroys in this overall process, the energy to failure of rock continues to increase, and as shown in Fig. 8 (b), and the change procedure of energy to failure depends on
In the ductile characteristic of rock material.
By mechanical analysis above it is found that rock sample is mainly pulled open in the double annulus uniaxial direct tensile experiments of more diameter cores
It is bad, it is possible thereby to derive that the calculation of Tensile Strength formula of rock sample is as follows:
In formula: FaMaximum axial load when being rock sample tension crack, N；r1It is the outer toroid radius of rock sample, m；r2It is
The interior annular radius of rock sample, m.
2, testing machine design is realized with function
Following main points should be paid attention in the double annulus uniaxial direct tensile Tensile Strength of Rock test process of more diameter cores:
1) it due to requiring to carry out core on coaxial sleeve brill twice, covers drill-through journey and the integrality and intensity of core is proposed sternly
The requirement of lattice.It is required that core can bear the processing disturbance that set bores operation, completely, do not influenced by micro-structure face；
2) it requires the length of rock sample to be at least 1.5 times of core diameter, or is 2 times of core diameter；Specific size is wanted
It asks and should be greater than 100mm for core length；If rock particles is larger, core length can be used to be greater than 200mm to meet rock sample
The representative requirement in tensile region, tensile region should be the 1/2~1/3 of rock sample length；
3) it should guarantee that core, interior annular and outer toroid are same using stringent operation safeguard during double annulus sets bore
Axis is concentric；
4) the related rule that the load operation of experimentation can be tested with reference to related experiment regulation about uniaxial compressive strength
It is fixed.Can be used loading stress rate or deformation rate control loading speed, it is proposed that loading stress rate be 0.05MPa/s.
If experiment condition allows, record experiment Complete Stress-Strain Process curve.
5) in loading procedure, it should guarantee that load axis is parallel and coaxial with rock sample using necessary measure.
According to the requirement of experiment and mechanical analysis of front, researches and develops and manufacture the double annulus uniaxial direct tensiles of dedicated more diameter cores
Tensile Strength of Rock testing machine, the testing machine include loading system, pressure monitoring and data collection system, loading frame and sample
Three parts of grasping system, specific structure chart are as shown in Figure 9.
The loading system includes upper platen (16), bulb (10), ball seat (9), tower-shaped spring (12), flexural pivot end cap
(11), oil cylinder (8), pressing disc (3), guide sleeve (5) and guide plate (4).The oil cylinder is the output device of hydraulic power, at this
Electric oil pump and hand oil pump two systems are equipped in set experimental machine, the highest output pressure of electric oil pump is 30MPa, load
Rate can control 0.005MPa/s；The highest output pressure of hand oil pump be 60MPa, pulsed output pressure, LOADING RATES with
People's operating frequency is closely related, when manual operation, can be controlled completely according to the variation of digital display pressure monitor operating frequency with
Meet requirement of experiment.The upper platen and the pressing disc, which are constituted, applies stressed main power source and reaction frame to sample.Institute
The structure for stating bulb, ball seat, tower-shaped spring and flexural pivot end cap composition can guarantee that applied load and rock sample are coaxially put down
Row.The structure of the guide sleeve and guide plate composition guarantees that applied load is coaxially parallel with rock sample, and load is in
In loading frame plane set by testing machine.
The pressure monitoring and data collection system include sensor and data acquisition subsystem, pressure on the number display screen,
Monitor pressure gauge and laptop data acquisition subsystem.The sensor and data acquisition subsystem are high-precision A/D pressure
Force snesor can be connect with computer, realize computer observe in real time, recording and storage.These accessories are all made of industrialized
Standardized product is selected the needs that can meet testing machine according to actual needs, is not described in detail here.It is required that pressure sensor
Precision is better than 0.1%.
The loading frame and sample clamping system include variable diameters rock sample interior annular platen, variable diameters rock sample outer toroid pressure
Disk, lower beam, column, column fixed ring and upper beam.Wherein lower beam, column, column fixed ring and upper beam constitute whole
The load of a testing machine and counter-force bearing system, basic principle are similar with point loading, Brazil's splitting pilot system of disk.For sample
Product clamping, needs to meet the core rock sample requirement of experiment of multiple diameter.In testing machine R&D process, it is desirable to be reduced as far as
Core both ends are simply cut, are polished by sample manufacturing procedure, and then set bores double annulus, are just able to satisfy requirement of experiment.For common
The geological prospecting borehole core of specification, diameter are respectively 49 ± 0.5mm of Φ, 62 ± 0.5mm of Φ, 89 ± 0.5mm of Φ, Φ 94
±0.5mm.For these sizes, with reference to the thick cylinder principle of rock mechanics, the ratio between the internal-and external diameter of each cylinder is no more than
0.75, be based on these size factors, the different diameter of rock sample interior annular design of platens, including Φ 20mm, Φ 25mm, Φ 30mm,
Φ 35mm, Φ 40mm, Φ 45mm, Φ 50mm, Φ 55mm, totally 8 diameters, rock sample outer toroid platen diameter includes Φ 30mm, Φ
35mm, Φ 40mm, Φ 45mm, Φ 50mm, Φ 55mm, Φ 60mm, Φ 65mm, totally 8 diameters can be according to survey in experimentation
Test agent flexibly selects set to bore size, finally averages to obtain final tested volume.It is set between pressing disc on variable diameters rock sample
The device that can adjust its space up and down is counted into, the stroke space of oil cylinder can satisfy the range demands of 300mm, preferably to meet
The flexible convenience for being applicable in requirement and test operation of different rock sample sizes.
The advantages and benefits of the present invention are:
(1) testing machine can monitor and record the entire test process of rock sample tensile failure, and quickly determine that rock is direct
Tensile strength quantitative values when stretching, and test philosophy and process precise and reliable have filled up the sky of this domestic research field
It is white.
(2) testing machine cooperation domestic current four kinds of geological prospecting (geotechnical engineering investigation) bore diameters (Φ 76 ±
94 ± 0.5mm of 0.5mm, Φ, 110 ± 0.5mm of Φ, 130 ± 0.5mm of Φ) and design, it can effectively supplement conventional rock physics power
The experiment parameter of test is learned, and laboratory sample preparation is required lower, it is only necessary to which core both ends are polished into simultaneously (coaxial) set with one heart
Brill can be met the requirements, and the requirement to laboratory sample is well below mentioned-above rock strength test.
(3) transport of this equipment operation is easy.
Detailed description of the invention
Present invention will be further explained below with reference to the attached drawings and examples.
Fig. 1 is several clamping devices of rock sample direct tensile test.
In figure, (a) is rock sample uniaxial direct tensile clamper, be (b) glued cylindrical sample (c) is that " dog bone shape " is biaxial stretch-formed
Rock sample uniaxial direct tensile clamper.
Fig. 2 is revised direct tensile test device, can be pulling force by pressure conversion.
Fig. 3 is disk splitting test method schematic diagram.
In figure, 1 is hard steel wire, and 2 be bearing plate, and 3 be discoid rock sample, and 4 be to answer tabletting, and 5 be pressure sensor,
6 be stress, and 7 be strain, and 8 be ess-strain acquisition system, and 9 be computer processing system, and 10 be the tensile modulus of elasticity of rock.
Fig. 4 is Brazilian test loading method schematic diagram.
In figure, (a) is to be loaded directly into, and is (b) gasket load, is (c) filler strip load, is (d) arc load, FaTo apply
Load, D are rock sample diameter.
Fig. 5 is rock beam four-point bending tension test test schematic diagram.
Fig. 6 is rock beam three-point bending tension test test schematic diagram.
Fig. 7 is the double annulus uniaxial direct tensile Tensile Strength of Rock test philosophy schematic diagrames of more diameter cores of the present invention.
In figure, 1 is the anticipation plane of disruption.
Fig. 8 is the double annulus uniaxial direct tensile experimental test procedures mechanical analysis figures of more diameter cores of the present invention.
In figure, (a) is that the double annulus uniaxial direct tensile Tensile Strength of Rock of diameter core test basic stress model and tensile region
Signal is (b) tensile strength test stress-strain complete process curve and energy to failure signal, is (c) before tensile strength test is destroyed
Force modes and sample interior stress envelope, (d) be tensile strength test destroy when force modes and sample interior answer
Power distribution map, (e) be tensile strength test destroy after force modes and sample interior stress envelope, 1 is tensile region, and 2 are
Uniaxial tensile strength, 3 be energy to failure GfContinue to increase.
Fig. 9 is the double annulus uniaxial direct tensile Tensile Strength of Rock testing machine structure signals of more diameter cores of the present invention
Figure.
In figure, 1 is upper beam, and 2 be column, and 3 be pressing disc, and 4 be guide plate, and 5 be guide sleeve, and 6 be column fixed ring, 7
It is lower beam, 8 be oil cylinder, and 9 be ball seat, and 10 be bulb, and 11 be flexural pivot end cap, and 12 be tower-shaped spring, and 13 be outside variable diameters rock sample
Annulus platen, 14 be rock sample, and 15 be variable diameters rock sample interior annular platen, and 16 be upper platen, and 17 be sensor and data acquisition system
System.
Specific embodiment
Embodiment 1
Referring to Fig. 9:
A kind of double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores, the testing machine include load system
System, pressure monitoring and three data collection system, loading frame and sample clamping system parts.
The loading system includes upper platen (16), bulb (10), ball seat (9), tower-shaped spring (12), flexural pivot end cap
(11), oil cylinder (8), pressing disc (3), guide sleeve (5) and guide plate (4).The oil cylinder (8) is the output device of hydraulic power,
Electric oil pump and hand oil pump two systems are equipped in this set experimental machine, the highest output pressure of electric oil pump is 30MPa,
LOADING RATES can control 0.005MPa/s；The highest output pressure of hand oil pump is 60MPa, pulsed output pressure, load
Rate and people's operating frequency are closely related, when manual operation, can control operation frequency according to the variation of digital display pressure monitor completely
Rate is to meet requirement of experiment.The upper platen (16) and the pressing disc (3) constitute and apply stressed main power source to sample
And reaction frame.The structure that the bulb (10), ball seat (9), tower-shaped spring (12) and flexural pivot end cap (11) form can guarantee institute
The load of application is coaxially parallel with rock sample.The structure of the guide sleeve (5) and guide plate (4) composition guarantees applied lotus
Load is coaxially parallel with rock sample, and load is in loading frame plane set by testing machine.
The pressure monitoring and data collection system (17) include that sensor and data acquisition subsystem, pressure on the number are shown
Screen, monitoring pressure gauge and laptop data acquisition subsystem.The sensor and data acquisition subsystem are high-precision A/D
Pressure sensor can be connect with computer, realize computer observe in real time, recording and storage.The Pressure Sensor Precision is excellent
In 0.1%.
The loading frame and sample clamping system include variable diameters rock sample interior annular platen (15), variable diameters rock sample outer toroid
Platen (13), lower beam (7), column (2), column fixed ring (6) and upper beam (1).Wherein lower beam (7), column (2), vertical
Column fixed ring (6) and upper beam (1) constitute load and the counter-force bearing system of entire testing machine.The rock sample interior annular platen
(15) design has including Φ 20mm, Φ 25mm, Φ 30mm, Φ 35mm, Φ 40mm, Φ 45mm, Φ 50mm, Φ 55mm, totally 8 it is straight
Diameter, rock sample outer toroid platen (13) diameter includes Φ 30mm, Φ 35mm, Φ 40mm, Φ 45mm, Φ 50mm, Φ 55mm, Φ
60mm, Φ 65mm, totally 8 diameters.It is designed to that the dress in its space can be adjusted up and down between the upper and lower platen of variable diameters rock sample
It sets, the stroke space of the oil cylinder (8) can satisfy the range demands of 300mm, preferably to meet the suitable of different rock sample sizes
With requiring and the flexible convenience of test operation.
Application examples 1
After experimental facilities is successfully researched and developed, the experiment of first batch has been carried out using several samples.The loading speed of experiment is
0.02MPa/s, the inner circle ring diameter of rock sample are 30mm, and outer circle ring diameter is 60mm, and the outer diameter of rock sample is 95mm.Test double annulus
The degree of eccentricity be about 3mm.Experimental result is as shown in table 2.
Certain the double annulus uniaxial direct tensile experimental results table of table 2
Finally, it should be noted that obviously, the above embodiment is merely an example for clearly illustrating the present invention, and simultaneously
The non-restriction to embodiment.For those of ordinary skill in the art, it can also do on the basis of the above description
Other various forms of variations or variation out.There is no necessity and possibility to exhaust all the enbodiments.And thus drawn
The obvious changes or variations of stretching are still in the protection scope of this invention.
Claims (2)
- The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of the core of diameter more than 1., it is characterised in that: the testing machine includes adding Three loading system, pressure monitoring and data collection system, loading frame and sample clamping system parts, the loading system includes upper Platen, bulb, ball seat, tower-shaped spring, flexural pivot end cap, oil cylinder, pressing disc, guide sleeve and guide plate；The oil cylinder is hydraulic dynamic The output device of power；The upper platen and the pressing disc, which are constituted, applies stressed main power source and reaction frame to sample；Institute The structure for stating bulb, ball seat, tower-shaped spring and flexural pivot end cap composition guarantees that applied load is coaxially parallel with rock sample；Institute The structure for stating guide sleeve and guide plate composition guarantees that applied load is coaxially parallel with rock sample, and load is in testing machine In set loading frame plane, the pressure monitoring and data collection system include sensor and data acquisition subsystem, pressure Power digital display screen, monitoring pressure gauge and laptop data acquisition subsystem；The sensor and data acquisition subsystem For high-precision A/D pressure sensor, connect with computer, realize computer observe in real time, recording and storage；The pressure sensing Device precision is better than 0.1%, and the loading frame and sample clamping system include variable diameters rock sample interior annular platen, outside variable diameters rock sample Annulus platen, lower beam, column, column fixed ring and upper beam；The lower beam, column, column fixed ring and upper beam group Load and counter-force bearing system at entire testing machine；The rock sample interior annular design of platens has Φ 20mm, Φ 25mm, Φ 30mm, Φ 35mm, Φ 40mm, Φ 45mm, Φ 50mm, Φ 55mm, totally 8 diameters；The rock sample outer toroid design of platens has Φ 30mm, Φ 35mm, Φ 40mm, Φ 45mm, Φ 50mm, Φ 55mm, Φ 60mm, Φ 65mm, totally 8 diameters；The variable diameters rock It is designed to that the device in its space can be adjusted up and down between the upper and lower platen of sample, the stroke that the stroke space of oil cylinder meets 300mm is wanted It asks；The measurement of rock tensile strength is carried out using the double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of above-mentioned more diameter cores Step are as follows:1) core of acquirement is cut into suitable length, the length of core should be 2 times of core diameter, and tensile region is that rock sample is long The 1/2~1/3 of degree；Core both ends are polished；2) by the core of well cutting from top and bottom respectively cover brill two with core coaxial and different-diameter annulus cylinder；3) core prepared is placed on the loading frame of the double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores, Guarantee that load axis is parallel and coaxial with rock sample；Selection applies active load from top-loaded disk or bottom-loaded ring, starts Experiment, loading stress rate are0.05MPa/s；To an xial feed is applied at the top of rock sample, the support ring of rock sample bottom can apply one instead to rock sample Power, record experiment Complete Stress-Strain Process curve；The calculation of Tensile Strength formula of rock sample is as follows:In formula: FaMaximum axial load when being rock sample tension crack, N；r1It is the outer toroid radius of rock sample, m；r2It is rock sample Interior annular radius, m.
- 2. the double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores as described in claim 1, it is characterised in that: It is equipped with electric oil pump and hand oil pump, the highest output pressure of electric oil pump is 30MPa, LOADING RATES control to 0.005MPa/s； The highest output pressure of hand oil pump is 60MPa, pulsed output pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610186531.3A CN105910909B (en) | 2016-03-29 | 2016-03-29 | The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610186531.3A CN105910909B (en) | 2016-03-29 | 2016-03-29 | The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105910909A CN105910909A (en) | 2016-08-31 |
| CN105910909B true CN105910909B (en) | 2018-12-21 |
Family
ID=56745254
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610186531.3A Active CN105910909B (en) | 2016-03-29 | 2016-03-29 | The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105910909B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20230400396A1 (en) * | 2022-06-13 | 2023-12-14 | Chengdu University Of Technology | Multifunctional rock mechanics tester |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106286579B (en) * | 2016-11-01 | 2019-01-18 | 福建省计量科学研究院 | The thrust articulated bearing structure of load sensor |
| CN106644530A (en) * | 2016-11-23 | 2017-05-10 | 中车齐齐哈尔车辆有限公司 | Test apparatus, fatigued test method and output force test method of railway freight car integrated brake cylinder |
| CN107741357B (en) * | 2017-10-11 | 2020-06-05 | 河南理工大学 | Arc tensile creep test method for rock |
| CN108956938B (en) * | 2018-05-25 | 2023-07-07 | 成都理工大学 | Freeze-thawing cycle rock deformation measuring device and measuring method thereof |
| CN109855973A (en) * | 2019-01-22 | 2019-06-07 | 东北大学 | A kind of three axis uniaxial direct tensile indoor experimental apparatus of rock and method |
| CN110208053B (en) * | 2019-01-25 | 2021-05-25 | 东北大学 | Method for manufacturing and loading layered rock sheet sample |
| CN110749428A (en) * | 2019-10-14 | 2020-02-04 | 中国矿业大学 | Hoist brake reliability test bed for simulating actual working conditions and test method thereof |
| CN110987635B (en) * | 2019-11-15 | 2021-11-30 | 河海大学 | Test device of soil core wall water conservancy splitting |
| CN110987619B (en) * | 2019-12-13 | 2022-03-29 | 山西省交通科技研发有限公司 | System for testing tensile strength of large triaxial sample of curing agent stabilized cement soil |
| CN112345355B (en) * | 2020-11-02 | 2022-04-15 | 西南石油大学 | Cement stone tensile strength testing device and method |
| CN112525671B (en) * | 2021-01-21 | 2021-07-30 | 东北石油大学 | Rock direct tensile test device under true triaxial confining pressure condition |
| CN112903452B (en) * | 2021-02-04 | 2023-10-10 | 太原理工大学 | Device and method for testing tensile capacity of multi-row group columns of horizontal goaf under influence of disturbance |
| CN112858013B (en) * | 2021-02-04 | 2023-10-24 | 太原理工大学 | Device and method for testing tensile resistance of multi-row group columns in inclined goaf |
| CN113218769B (en) * | 2021-04-23 | 2022-06-10 | 河海大学 | Indirect stretching device and method for testing tensile strength of rock |
| CN115824811B (en) * | 2023-01-09 | 2023-06-09 | 水利部交通运输部国家能源局南京水利科学研究院 | Brazilian split-based brittle material stretching dynamic full curve testing device and method |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU599190A1 (en) * | 1973-04-02 | 1978-03-25 | Коммунарский Горнометаллургический Институт | Device for testing rock specimens |
| CN200965500Y (en) * | 2006-11-08 | 2007-10-24 | 四川大学 | Spring supporting lower fixture for direct tensile test |
| CN201100859Y (en) * | 2007-11-30 | 2008-08-13 | 山东大学 | Crisp material testing part mould and its fit flexing test clamper |
| CN101819111A (en) * | 2010-03-30 | 2010-09-01 | 中南大学 | Method for testing tensile modulus of brittle material |
| CN202101902U (en) * | 2011-06-27 | 2012-01-04 | 长沙理工大学 | Anti-position loading device for structure test |
| CN103471923A (en) * | 2013-09-25 | 2013-12-25 | 中国地震局地壳应力研究所 | Rapid testing machine for multi-diameter rock core hydraulic fracturing tensile strength |
| CN103543066A (en) * | 2013-10-24 | 2014-01-29 | 山东大学 | Sleeve-spliced rock direct tensile test device and method |
| CN103575597A (en) * | 2013-10-24 | 2014-02-12 | 湖南工业大学 | Axial compression column non-loading reinforcement test device |
| CN104297028A (en) * | 2014-10-11 | 2015-01-21 | 四川大学 | Rock test piece for direct tensile test and rock direct tensile testing method |
| CN104596856A (en) * | 2015-01-16 | 2015-05-06 | 重庆大学 | Uniaxial tension compression system |
| CN104849143A (en) * | 2015-05-22 | 2015-08-19 | 长沙理工大学 | Uniaxial tension device and testing method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3391139B2 (en) * | 1995-03-15 | 2003-03-31 | 株式会社島津製作所 | Tensile impact tester |
-
2016
- 2016-03-29 CN CN201610186531.3A patent/CN105910909B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU599190A1 (en) * | 1973-04-02 | 1978-03-25 | Коммунарский Горнометаллургический Институт | Device for testing rock specimens |
| CN200965500Y (en) * | 2006-11-08 | 2007-10-24 | 四川大学 | Spring supporting lower fixture for direct tensile test |
| CN201100859Y (en) * | 2007-11-30 | 2008-08-13 | 山东大学 | Crisp material testing part mould and its fit flexing test clamper |
| CN101819111A (en) * | 2010-03-30 | 2010-09-01 | 中南大学 | Method for testing tensile modulus of brittle material |
| CN202101902U (en) * | 2011-06-27 | 2012-01-04 | 长沙理工大学 | Anti-position loading device for structure test |
| CN103471923A (en) * | 2013-09-25 | 2013-12-25 | 中国地震局地壳应力研究所 | Rapid testing machine for multi-diameter rock core hydraulic fracturing tensile strength |
| CN103543066A (en) * | 2013-10-24 | 2014-01-29 | 山东大学 | Sleeve-spliced rock direct tensile test device and method |
| CN103575597A (en) * | 2013-10-24 | 2014-02-12 | 湖南工业大学 | Axial compression column non-loading reinforcement test device |
| CN104297028A (en) * | 2014-10-11 | 2015-01-21 | 四川大学 | Rock test piece for direct tensile test and rock direct tensile testing method |
| CN104596856A (en) * | 2015-01-16 | 2015-05-06 | 重庆大学 | Uniaxial tension compression system |
| CN104849143A (en) * | 2015-05-22 | 2015-08-19 | 长沙理工大学 | Uniaxial tension device and testing method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20230400396A1 (en) * | 2022-06-13 | 2023-12-14 | Chengdu University Of Technology | Multifunctional rock mechanics tester |
| US11892432B2 (en) * | 2022-06-13 | 2024-02-06 | Chengdu University Of Technology | Multifunctional rock mechanics tester |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105910909A (en) | 2016-08-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105910909B (en) | The double annulus uniaxial direct tensile Tensile Strength of Rock testing machines of more diameter cores | |
| Huang et al. | The effect of loading rate on the behavior of samples composed of coal and rock | |
| Tarasov et al. | Universal criteria for rock brittleness estimation under triaxial compression | |
| CN103471923B (en) | Rapid testing machine for multi-diameter rock core hydraulic fracturing tensile strength | |
| CN105158087B (en) | A kind of improved method that rock shearing experiment is carried out using rock triaxial apparatus | |
| CN106680079A (en) | Piezoelectric stack direct driving type macro-micro combined biaxial stretching-fatigue testing system | |
| CN106644687A (en) | Small-punch and continuous indentation integrated tester system | |
| Gong et al. | Load–unload response ratio characteristics of rock materials and their application in prediction of rockburst proneness | |
| CN101776551B (en) | Method for testing uniaxial strength mean value of material through instrumented microindentation | |
| CN204718885U (en) | Material Micro Mechanical Properties is biaxial stretch-formed-fatigue test system | |
| CN107907409A (en) | A kind of method, equipment and the storage device of definite rock crack initiation stress | |
| CN104007009B (en) | A kind of testing of materials fixture for clamping tiny sample | |
| Gong et al. | Identifying crack compaction and crack damage stress thresholds of rock using load–unload response ratio (LURR) theory | |
| Rouabhi et al. | Phenomenological behavior of rock salt: On the influence of laboratory conditions on the dilatancy onset | |
| CN101710042A (en) | Device and method for measuring I-type creep fracture toughness and fracture toughness of rock | |
| Vil’deman et al. | Material testing by plotting total deformation curves | |
| CN106644773A (en) | Impact performance testing device for materials | |
| CN104374642A (en) | Testing method for measuring tensile strength of rock by multiple times of splitting | |
| CN103674727A (en) | Method and device for detecting bending strength of battery | |
| CN107389457A (en) | Rock mechanics experiment machine based on carbon fiber balancing gate pit | |
| CN107831069A (en) | A kind of method that elastic deformation energy at rock material peak load point is determined in Point Load Tests | |
| CN104596856A (en) | Uniaxial tension compression system | |
| CN209123872U (en) | The device of dynamic monitoring deformation index under a kind of high-temperature and high-pressure conditions in reaction kettle | |
| CN103499493B (en) | A kind of method determining fragile material splitting-tensile strength | |
| Franklin et al. | The point load strength test |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 100085, Anning Road, Beijing, Haidian District, No. 1 Patentee after: National natural disaster prevention and Control Research Institute, Ministry of emergency management Address before: 100085 Beijing city Haidian District, Xisanqi Ning Zhuang Road No. 1 box 2855 Patentee before: THE INSTITUTE OF CRUSTAL DYNAMICS, CHINA EARTHQUAKE ADMINISTRATION |