The test method of Tensile Strength of Rock under any sheet reason angle is surveyed by single rock sample
Technical field
The present invention relates to Tensile Strength of Rock and measure field, particularly a kind of by under single rock sample survey any sheet reason angle
The test method of Tensile Strength of Rock.
Background technology
In underground engineering design and construction, the tensile strength of rock is a very important mechanical index.Underground work
Journey is enclosed rock mass and is often in the stress state of complexity, such as railway tunnel, vcehicular tunnel, engineering slope and underground engineering hole
The country rock body of room, some places are in tensile stress state, and some positions are then in compressing stress state, due to rock
The tensile strength of stone is far below comprcssive strength, so country rock always starts to destroy from Tension Stress Zone.Therefore, correctly carry out
Underground country rock body stress state region divides, and the determination i.e. destroying hazardous area is that underground engineering wall rock stability analysis is commented
The key of valency, and Tensile Strength of Rock determines that one of the basic data in surrounding rock failure of engineering district.
Rock mass is commonly present various structures face, such as: crack, sheet reason, joint, layer reason, tomography, fracture belt etc. and
Various combinations, near these structural planes, the more complete rock mass of cohesion between the rock particles of composition rock mass reduces,
The tensile strength of rock mass has bigger difference under different angle of beddings.In Practical Project, beded rock mass is respectively to different
Property clearly, the stability after excavating for Correct Analysis anisotropic rock mass, it is necessary to accurately grasp different sheet reason angle
The tensile strength values of rock mass.
At present, the indoor measurement method of Tensile Strength of Rock typically uses uniaxial direct tensile method and split the law, and rock sample is straight
Connecing in tension test, due to clamping and ensure that tensile load axis overlaps with sample axis and to have certain difficulty, employing is directly
Connecing drawing process, to carry out Tensile Strength of Rock test relatively fewer, and more generally uses split the law, i.e. Brazil's examination
Test method, the tensile strength of indirect determination rock.Regardless of whether use uniaxial direct tensile method or traditional Brazilian test method,
It is all to measure it by the natural reason angle rock sample that screening is different when measuring different sheet reason angle Tensile Strength of Rock
Tensile strength.Thus, the problem that following two exists i.e. is caused:
1, test rock sample sample is big.For obtaining the rock sample of different natural angle sheets reason, it is necessary to carry out the brill of a large amount of sillar
Taking and screen, this necessarily causes testing human and material resources and the increase of time cost.
2, any sheet reason angle rock sample acquisition difficulty is big.Natural rock mass sheet reason structure is complicated, is difficult to find several identical
Specifying sheet reason angle rock sample to test, in most cases similar sheet reason structure rock sample can only be classified as one group, this makes
Test error is bigger.
Summary of the invention
The technical problem to be solved is to provide a kind of by Rock Anti under single rock sample survey any sheet reason angle
The test method of tensile strength, can reduce the demand for rock sample sample size, also can strengthen the accuracy of result of the test.
For solving above-mentioned technical problem, the technical solution adopted in the present invention is: a kind of by single rock sample any sheet of survey
The test method of Tensile Strength of Rock under reason angle, comprises the following steps:
One, rock sample to be measured is prepared;
Rock sample is cylinder specimen, and rock sample sheet reason direction should be axially in parallel with it;
Two, the selected sheet reason angle with rock sample sheet reason, makees diametral compression test for the first time along rock sample sheet reason direction;
Three, by cementing for the rock sample after splitting;
Four, change non-cementing position, reselect and the different angles of rock sample sheet reason, carry out second time diametral compression test;
Five, by cementing for the rock sample after splitting;
Repeat step 4, five, obtain maximum load power during the rock sample cleavage fracture of arbitrary demand and rock sample sheet reason angle.
Described rock sample ratio of height to diameter is 0.5~1, and rock sample two ends polish, and smooth-sided compression candles is without projection.
The rock sample destroyed is taken out, pressing after uniform application binding material on rock sample surface of fracture so that it is contact surface is basic
Tight, both ends of the surface guarantee smooth, smooth-sided compression candles, treat that its contact surface glue consolidates;
Tensile strength after described binding material consolidation should be tried one's best close to the tensile strength of rock sample to be measured.
By repeatedly measured result substitution rock cleavage test calculation of Tensile Strength formula:
Wherein: R is Tensile Strength of Rock, maximum load power when P is the rock failure mechanism of rock, D is cylinder specimen diameter,
H is circular height of specimen;
Obtain surveyed Tensile Strength of Rock R1、R2···Rn。
It is a kind of by the test method of Tensile Strength of Rock under single rock sample survey any sheet reason angle that the present invention provides, this
The measuring method of invention only i.e. can get any sheet of demand by a rock sample or minority rock sample are carried out diametral compression test
The tensile strength of reason angle rock, has the advantages that
1, rock sample sample size is greatly reduced.If traditional method wants to obtain the tensile strength values of different sheet reason angle rock,
Then needing to obtain the rock sample of a large amount of different sheet reason angle, the present invention is then the folder by adjusting splitting surface and rock sample sheet reason
Angle, repeatedly tests the tensile strength values of i.e. available different sheet reason angle rock to single or minority rock sample.
2, the result of the test error that rock sample discrete type causes is reduced.Different rock samples, even if drilling through in same sillar,
All may there is larger difference in its lithology, traditional measure different sheet reason angle by being tested to multiple rock samples
Inevitably there is the error caused due to lithology difference in the method for Tensile Strength of Rock, and the present invention is only to one
Rock sample carries out repeating test, greatly reduces the result of the test error caused due to rock sample discrete type.
3, the tensile strength values of rock under any sheet reason angle is accurately obtained.The haircut of natural rock mass sheet is educated extremely complex,
The rock sample going for a certain particular patch reason angle is extremely difficult, and the present invention is then by adjusting splitting surface with special
Angle between inside stator reason rock sample sheet, it is thus possible to the tensile strength of any sheet of point-device acquisition reason angle rock
Value.To sum up, the tensile strength that the present invention manages angle schist for measuring different sheet is compared traditional method and is had obvious technology
Superiority and extensively engineering application prospect.
;Accompanying drawing explanation
The invention will be further described with embodiment below in conjunction with the accompanying drawings:
Fig. 1 is rock sample and the schematic diagram of rock sample sheet reason in the present invention.
When Fig. 2 is repeated loading in the present invention, splitting surface chooses schematic diagram.
Fig. 3 is that in the present invention, schematic diagram fixed by rock sample.
In figure: rock sample 1, for the first time splitting surface 2, for the second time splitting surface 3, for the third time splitting surface 4, the 4th splitting
Face 5, n-th splitting surface 6, diametral compression test device 7, pressure head 8, rock sample sheet reason 9.
Detailed description of the invention
A kind of by the test method of Tensile Strength of Rock under single rock sample survey any sheet reason angle, comprise the following steps:
One, rock sample 1 to be measured is prepared;
If rock sample cylinder specimen, rock sample sheet reason direction should be axially in parallel with it;As shown in fig. 1.
Preferably, described rock sample 1 ratio of height to diameter is 0.5~1, and rock sample 1 two ends polish, and smooth-sided compression candles is without projection.
Two, the selected sheet reason angle with rock sample sheet reason 9, manages 9 directions along rock sample sheet and makees diametral compression test for the first time;
After instrument to be tested and rock sample are ready to, rock sample are put into RMT-150C rock cleavage assay device 7 and fixes,
It is its upper and lower two end faces at cylindrical splitting, rotates rock sample and make the plane of schistosity of its rock sample sheet reason 9 and upper and lower filler strip 10
In a in required reason angle, such as Fig. 11.Debugging operation test instrument, diametral compression test starts, until
Rock sample destroys, and records maximum load power P when this rock sample 1 destroys1。
Three, by cementing for the rock sample 1 after splitting;
The rock sample destroyed is taken out, firmly pressing after uniform application binding material on rock sample surface of fracture so that it is contact surface
Basic tight, both ends of the surface preserve smooth, and rock sample is returned to destroy front state by smooth-sided compression candles as far as possible.Then will
It is placed on the desktop of dried flat, and consolidation time, depending on cementing material character and ambient temperature, typically takes 12h
It is advisable.Treat that its contact surface glue consolidates.The pre-stage test that inventor passes through finds, if not using cementing mode, and weight
During splitting, rock sample splitting surface can disconnect at previous splitting surface again, and splitting surface cannot run through whole rock sample cross section, uses glue
After the mode of knot, it is ensured that during rock sample splitting, internal force conducts and the recovery of its mechanical state.
Tensile strength after described binding material consolidation should be tried one's best close to the tensile strength of rock sample 1 to be measured.
Four, change non-cementing position, reselect and the different angles of rock sample sheet reason 9, the such as a in Fig. 12, enter
Row second time diametral compression test;
Owing to each splitting surface does not repeats, and rock sample destroys the most relevant with the tensile strength of splitting surface, and actual rock sample is cementing
Locating cementing thickness and be about about 0.5mm, a diameter of 50mm of rock sample, cementing area accounts for whole splitting surface less than 1%.
We define cement plane factor of influence ξ=δ × λ to experimental test result, and wherein δ is that cementing place area accounts for whole splitting
Broken face ratio, λ is the tensile strength ratio of binding material and rock, due to δ < 1%, according to binding material with
The tensile strength of rock is more little than difference, then it is very limited amount of on the impact of result.In addition, it is contemplated that schist
Inhomogeneities, for reducing this impact, the splitting surface angle of twice splitting should be greater than 30 ° and is advisable.
Five, by cementing for the rock sample after splitting;
Repeat step 4, five, obtain arbitrary demand and rock sample sheet and manage 9 angle anRock sample cleavage fracture time the most greatly
Load power Pn。
By repeatedly measured result substitution rock cleavage test calculation of Tensile Strength formula:
Wherein: R is Tensile Strength of Rock, maximum load power when P is the rock failure mechanism of rock, D is cylinder specimen diameter,
H is circular height of specimen;
Or
Wherein: R is Tensile Strength of Rock, maximum load power when P is the rock failure mechanism of rock, a is the cube specimen length of side;
Obtain surveyed Tensile Strength of Rock R1、R2···Rn。
Subordinate list 1 is traditional multiple rock sample rock sample single with the present invention different sheet reason angle Tensile Strength of Rock (Mpa)
Measurement result contrasts.
Note: scheme 1 is traditional method, have chosen 5 pack reason angles, and often group is 5 rock samples,;Scheme 2 is this
The experimental technique scheme of invention, have chosen 5 sheet reasons and axially in parallel rock sample, and in upper table, result is each group of mensuration
The meansigma methods of result.
As can be seen from the above table, under each sheet reason angle, the result of the test deviation of two kinds of methods is all below 10%, thus
Also demonstrating the accurate reasonability of the technical program, scheme 1 uses 25, rock sample altogether in addition, and scheme 2 is 5,
Scheme 2 saves the rock sample of 80% than scheme 1, it is seen that the superiority in economy of the present invention.