Direct shear test machine for rock
One, invention field
The present invention relates to a kind of testing machine of testing the shear of rock mechanical property, particularly relate to and be used for the direct shear test machine for rock that the cube specimen to forms such as rock, rock/rock, rock/mix earth and weak intercalated layer, solid structure faces carries out shear test.
Two, background technology
According to the regulation of national standard and department's rules standard, direct shear test is the technological means of the Shear Strength Index of test rock and weak structural plane thereof.Owing to there is not unified direct shear test instrument manufacturer's standard, the rock direct shear test instrument that constituent parts is developed voluntarily all has very big difference from form, structure on using method.Because the singularity of rock mechanics experiment, loading system generally all is a fluid pressure type in its main frame of existing direct shear test machine for rock, and the form that loads frame then has cased beam integral frame-type, column cased beam combined type etc.; Shear box all adopts traditional shear box up and down, and it is several that measuring system mainly contains mechanical type, sensor digital display type, computer automatic analysis formula etc.Control mode mainly contains load control, rate of displacement control and electro-hydraulic servo control and most advanced but very expensive digital servo control.In addition, a spot of rock staight scissors rheological test instrument is also arranged.
No matter above-mentioned direct shear test machine for rock main frame is cased beam integral frame-type, or column cased beam combined type, and it is all complicated that it loads rack construction, testing machine heaviness so not only, and observe measure and the loading and unloading test specimen very inconvenient; Again owing to generally the horizontal loading sensor is installed in horizontal load cylinder pistons end, therefore it is stressed that measurement result is not only test specimen institute, the friction force that has also comprised roller bearing row assembly etc., therefore need to demarcate these friction force before the test, so that in test result, deduct, thereby make troubles to use, waste time and energy.How to develop a kind of promptly simple for structure, test condition is accurate, economical and practical, and direct shear test machine for rock easy to use again, purpose of the present invention just.
Three, summary of the invention
Purpose of the present invention is just in order to overcome the existing existing defective of direct shear test machine for rock, provides in a kind of test main frame vertical load to load frame and loads frame with horizontal loading and all adopt four-column type loading frame; Shear box adopts shearing component and combined type down cut assembly on the combined type; And adopt two ball seats and two ball systems and computer data acquiring automatic measurement system, and direct shear test machine for rock with load and two kinds of control modes of rate of displacement.This testing machine has simple for structure reasonable, and easy to use, test condition is accurate; Not only guarantee the even distribution of normal stress and shear stress, also realized strain rate control; Make shearing force measurement accurately and reliably; And have rock direct shear test and staight scissors rheological test two big functions, be the very high direct shear test machine for rock of present cost performance.
The objective of the invention is to realize by the following technical solutions:
Direct shear test machine for rock of the present invention is made up of test main frame, hydraulic pressure regulator, measuring system three parts.Wherein test main frame and comprise that mainly vertical load loads frame and horizontal loading loads frame, load cylinder, roller bearing heat-extraction system and parts such as ball system, bulb and ball seat, shear box and load transducer; Measuring system is carried out data acquisition process by computing machine, and technical essential of the present invention is:
Vertical load loading frame and horizontal loading load frame and all adopt four-column type loading frame in the test main frame, and vertical load loading frame is made of with following counter-force seat four columns and last counter-force seat, vertical load loads frame and also claims vertical loading frame, four columns upper end is connected with last counter-force seat, its lower end is connected with following counter-force seat, horizontal loading loads frame and is made of four-pull-rod and left counter-force seat and right counter-force seat, horizontal loading loads frame and also claims horizontal loading frame, the four-pull-rod left end is connected with left counter-force seat, and its right-hand member is connected with right counter-force seat;
Shear box adopts knockdown shearing component and the down cut assembly formation of going up in the test main frame, between last shearing component upper end and the vertical loading oil cylinder vertical load sensor that has bulb and ball seat is installed, vertical load sensor lower end is equipped with vertical load Forwarding pearl system again, and last shearing component is lifted on the pistons end of vertical loading oil cylinder with vertical load sensor that has bulb and ball seat and vertical load Forwarding pearl system; Be equipped with between down cut assembly and the following counter-force seat and have gathering sill De Xia Roll axle row assembly; The one horizontal loading sensor that has bulb and a ball seat also is installed between last shearing component left end and the left counter-force seat, horizontal loading sensor left end promptly has an end of bulb, ball seat that horizontal loading ball system is installed again, again horizontal loading sensor and horizontal loading ball system is lifted on the shearing component left end together; , horizontal load cylinder is installed on the right counter-force seat;
The counter-force seat was rigidly connected under direct shear test machine for rock base of the present invention and left counter-force seat, right counter-force seat reached, so that main frame has firm structure and firmly is positioned on the ground.
Shearing component that the present invention says constitutes by four kinds of different rigidity clip plate and corresponding stiffness bearers of size with the down cut assembly, and the test test specimen places between shearing component and the down cut assembly.
The top pressing plate of last shearing component is provided with the counter weight device of being made up of large and small different balancing weight.
The present invention tests and adopts vertical load sensor and horizontal loading sensor promptly to have two bulbs, two ball seat and two load ball systems in the main frame simultaneously, and vertical load ball system and horizontal loading ball system are firm ball ball system.
Horizontal loading sensor of the present invention is installed on passive shearing component one side, passive shearing component promptly is not provided with horizontal load cylinder one side's shearing component, passive shearing component of the present invention is shearing component, can avoid passive shearing component to be subjected to down the effect of the friction force of roller system like this, the power that load transducer measures is exactly the power that test specimen is subjected to.Therefore the accurate flow speed control valve of force feedback such as can carry out at the test of shear rate.
The present invention compared with prior art has following characteristics:
1, direct shear test machine for rock main frame of the present invention adopts the four-column type load to load frame, and it is simple for structure, and has reduced and made this; Come out fully in two sides of test specimen simultaneously, be very easy to measurement of test specimen experimental observation and test specimen loading and unloading like this.
2, the present invention will go up the end that shearing component, vertical load set sensor and vertical load ball system are lifted on the vertical loading oil cylinder piston together, and oil cylinder piston together rises it after the off-test, can change test specimen easily; After having avoided manually to take off each parts successively after test was finished, could change in the past, reduce the loaded down with trivial details work of changing test specimen.
3, invention is adopted as open combined type shearing component with traditional upper and lower shear box, has so not only made things convenient for experimental observation, and it is very convenient that the test specimen of different size specification is changed.
4, between horizontal loading sensor and left counter-force seat, installed horizontal loading ball system additional, and vertical load ball system has been installed above last shearing component, solved the problem that causes stress distribution inequality in the test specimen owing to the nonaffine deformation of test specimen in the process of the test well.
5, the present invention adopts the counterweight briquetting that setting varies in size on the top board of last shearing component, balance the off-centre of last shearing component center of gravity, the normal stress on the shear surface is evenly distributed.
6, horizontal loading sensor of the present invention is installed on passive shearing component one side, and the power that the horizontal loading sensor measures is exactly the power that test specimen is subjected to, and makes measurement more accurately, reliably like this.
7, the present invention such as also can carry out at the test of shear rate.
8, the present invention adopts computer automatic analysis and data acquisition, has improved accuracy of experimental results greatly.
Four, description of drawings
Fig. 1 is a direct shear test machine for rock main machine structure synoptic diagram of the present invention.
Fig. 2 is the left TV structure synoptic diagram of Fig. 1.
Fig. 3 is a system of the present invention connection diagram.
Five, specific embodiments
Below in conjunction with accompanying drawing by structure of the present invention, operating process, test process and embodiment are further described.
Among Fig. 1, the present invention tests in the main frame vertical load and loads frame and load frame with horizontal loading and all adopt four-column type loading frame, and vertical load to load frame be that vertical loading frame is made of four root posts 2 and last counter-force seat 4 and following counter-force seat 5, four root posts, 2 upper ends and last counter-force seat 4 usefulness nuts 18 are fastenedly connected, its lower end is fastenedly connected with following counter-force seat 5 usefulness nuts 18, it is that horizontal loading frame is made of four pull bars 3 and left counter-force seat 6 and right counter-force seat 7 that horizontal loading loads frame, four are fastenedly connected, it is that horizontal loading frame is made of four pull bars 3 and left counter-force seat 6 and right counter-force seat 7 that horizontal loading loads frame, four pull bar left ends are connected with left counter-force seat 6 usefulness nuts, and its right-hand member is connected with right counter-force seat 7 usefulness nuts;
Shear box adopts knockdown shearing component 12 and down cut assembly 13 formations of going up in the test main frame, the vertical load sensor 10 that has bulb 21 and ball seat 20 is installed between last shearing component 12 upper ends and the vertical loading oil cylinder 14, vertical load sensor 10 lower ends are equipped with vertical load Forwarding pearl system 8 again, and last shearing component 12 is lifted on the pistons end of vertical loading oil cylinder 14 with vertical load sensor 10 and vertical load Forwarding pearl system 8; Be equipped with between down cut assembly 13 and the following counter-force seat 5 and have gathering sill De Xia Roll axle row assembly 16; The one horizontal loading sensor 11 that has bulb 21 and a ball seat 20 also is installed between last shearing component 12 left ends and the left counter-force seat 6, horizontal loading sensor left end promptly has an end of bulb, ball seat that horizontal loading ball system 9 is installed again, again horizontal loading sensor 11 and horizontal loading ball system is lifted on shearing component 12 left ends together; Horizontal load cylinder 15 is installed in right counter-force seat 7 left ends;
Counter-force seat 5 was rigidly connected under tester base 1 of the present invention reached with left counter-force seat 6, right counter-force seat 7, so that this testing machine has firm structure and firmly is positioned on the ground.
Last shearing component 12 is made of four kinds of different rigidity clip plate and corresponding stiffness bearers of size, and down cut assembly 13 is made of four kinds of different rigidity clip plate and corresponding stiffness bearers of size equally; The top pressing plate of last shearing component 12 is provided with the counter weight device of being made up of the balancing weight that varies in size 17; So that the off-centre of shearing component center of gravity on the balance, and the normal stress on its shear surface is evenly distributed; Test specimen 19 places between shearing component 12 and the down cut assembly 13.
The present invention tests and adopts vertical load sensor 10 and the horizontal loading sensor 11 that has bulb, ball seat in the main frame, the test main frame has the two load ball system of two bulbs, two ball seat and vertical load ball system and horizontal loading ball system like this, and two load ball system is firm ball ball system; Horizontal loading sensor 11 is installed on passive shearing component one side, passive shearing component promptly is not provided with horizontal load cylinder one side's shearing component, the passive shearing component of the present invention is last shearing component 12, avoided its shearing component to be subjected to down the effect of the friction force of roller system like this, the power that load transducer measures is exactly the power that test specimen is subjected to.
Fig. 2 is the left TV structure synoptic diagram of Fig. 1, two root posts, can see that also level loads four pull bars 3 in the frame and goes up counter-force seat 4 and following counter-force seat 5 among Fig. 2 in seeing vertical load loading frame.
Among Fig. 3, direct shear test machine for rock of the present invention adopts at hydraulic pressure regulator 22 and between the horizontal load cylinder 15 the accurate flow speed control valve 23 that has pressure feedback is installed with testing in the main frame, the test of shear rate such as can carry out like this; Vertical load sensor 10 is sent test signal into signal conditioner 26 with horizontal loading sensor 11 in the test main frame, and its signal is again through A/D converter 27, and the signal through changing send capture card 28, and last capture card is sent signal into computer system 29 and handled.
Use its operation steps of testing machine of the present invention as follows:
At first guarantee the testing machine working power, miscellaneous parts such as oil cylinder oil mass, each measuring sensor are all normal, and load cylinder resets, the good oil cylinder head of Installation and Debugging extension elongation; After pressing test specimen size loading and unloading rigidity clip plate and stiffness bearer, screw shearing component 12 top briquetting screws, and add corresponding counter weight device 17; Down cut assembly 13 is pushed into horizontal load cylinder 15 1 side limited block places, loads onto satisfactory test specimen 19, utilize additive method such as guiding ruler to make centering before and after the test specimen, left and right sides automatic centering with hand operated transport.Add in the upper and lower surface of test specimen and to adjust pad, promptly according to the size and the decrement of test specimen, and in conjunction with this testing machine fixing cut seam (center line respectively has 1 millimeter up and down) and seam is cut in reservation; Call through test machine working power starts each and measures and data acquisition components and parts and zeroing then; Startup level and vertical hydraulic load cylinder adopt the fine motion form that the workplace of two loading systems and test specimen all are adjacent to, and fine motion can overcome the resistance of self with the oil cylinder piston bar and stretch out and be as the criterion; Unclamp the location swivel nut on vertical load sensor 10 four screw rods on every side, size as required takes down this four screw rods then; Can formally load this moment tests; Load onto the screw, screw rod and the location swivel nut that unload after test is finished, oil cylinder resets, and unloads test specimen, closing test machine working power.
Testing machine of the present invention can use the test specimen of four kinds of dimensions of 50 * 50 * 50 cubes of millimeters, 100 * 100 * 100 cubes of millimeters, 200 * 200 * 200 cubes of millimeters, 300 * 300 * 300 cubes of millimeters, and determines the rigidity clip plate in the combined type shearing component and the increase and decrease of stiffness bearer according to the dimensions of test specimen 19.As adopt the test specimen of 50 cubes of millimeter specifications to test, all three blocks of rigidity clip plates and stiffness bearers then are installed, then corresponding one deck rigidity clip plate and the stiffness bearer of taking down of dimensions of every increase.12 sandstone and mud stone test specimen through adopting 50 cubes of millimeter specifications are tested, and the result shows that normal stress is evenly distributed in the test, and test condition is accurate, and test findings is entirely true.It is very satisfied that test findings is made us, and test efficiency raising 120%, and testing crew is very light in entire test.