CN110987642A - Rigid-flexible composite true triaxial loading device of rubber film outer wrapping loading plate - Google Patents
Rigid-flexible composite true triaxial loading device of rubber film outer wrapping loading plate Download PDFInfo
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- CN110987642A CN110987642A CN201911380874.3A CN201911380874A CN110987642A CN 110987642 A CN110987642 A CN 110987642A CN 201911380874 A CN201911380874 A CN 201911380874A CN 110987642 A CN110987642 A CN 110987642A
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- 238000011068 loading method Methods 0.000 title claims abstract description 316
- 239000002131 composite material Substances 0.000 title claims abstract description 18
- 239000002689 soil Substances 0.000 claims abstract description 69
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 34
- 230000009471 action Effects 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 12
- 238000006073 displacement reaction Methods 0.000 claims description 10
- 238000007599 discharging Methods 0.000 claims description 2
- 238000012946 outsourcing Methods 0.000 claims 1
- 238000012360 testing method Methods 0.000 abstract description 27
- 239000011435 rock Substances 0.000 abstract description 25
- 238000010008 shearing Methods 0.000 abstract description 7
- 239000011148 porous material Substances 0.000 abstract description 3
- 239000010408 film Substances 0.000 description 27
- 230000008569 process Effects 0.000 description 9
- 230000008859 change Effects 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 238000009826 distribution Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 238000009827 uniform distribution Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000013590 bulk material Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004141 dimensional analysis Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
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- 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
- G01N3/12—Pressure testing
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- 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
- G01N3/02—Details
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- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
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Abstract
The invention provides a rigid-flexible composite true triaxial loading device for a rubber film outer wrapping loading plate, which comprises: a slide loading member and a rubber film; the sliding loading component comprises four rigid loading plates; the four rigid loading plates are respectively provided with a loading piston, and the loading pistons apply loads to the rigid loading plates; the four rigid loading plates are respectively overlapped in four directions to form a frame with a central accommodating space, and the central accommodating space of the frame is used for accommodating and clamping rock-soil samples; the rubber film wraps the frame and the rock and soil sample, and the flexible film applies load to the rock and soil sample along the direction perpendicular to the two sides of the frame. According to the invention, the rubber film is arranged outside the rigid loading plate, the loading piston connected with the rigid loading plate applies load, so that the pore water pressure can be directly measured, the pressure of the soil sample in the direction during shearing is smaller than the water pressure in the confining pressure chamber, and any Lode angle test of 0-360 degrees can be carried out.
Description
Technical Field
The invention relates to the field of rock-soil mechanical testing, in particular to a rigid-flexible composite true triaxial loading device for a rubber film outer wrapping loading plate.
Background
Three-dimensional analysis problems are often encountered in geotechnical engineering. The design and experimental study of true triaxial apparatus has been an active and challenging research area. The stress-strain intensity characteristic of rock soil is generally measured by adopting a true triaxial system. True triaxial testing means that cubic geotechnical specimens are subjected to uniform pressure (or strain) in three directions (or three axial directions). The true triaxial test has important significance for measuring the stress-strain performance of rock and soil under the load action of three main directions.
The existing loading device for true triaxial test can be divided into the following 3 types: (1) a rigid loading mode; (2) a flexible loading mode; (3) mixed boundary loading mode. The most widely used method is a mixed boundary loading method which solves many limitations in pure rigid and pure flexible loading, but the system also has some defects, such as easy interference at corners, and possibly soil extrusion, uneven stress and strain distribution if gaps exist between steel plates.
In addition to the above problems, the existing loading systems have no rubber membrane for sealing the sample to cover the loading plate, which is not directly applied to the rock-soil pattern, so that the water pressure in the soil hole cannot be directly measured.
Through retrieval, the chinese patent with application number 2018116106201 discloses a true triaxial experiment system and method for intelligent identification of bulk material void ratio, wherein, as shown in fig. 1, the first mechanical confining pressure loading assembly comprises a first mechanical confining pressure controller, a first mechanical confining pressure loading rod and a first mechanical confining pressure loading plate; the outer end of the first mechanical confining pressure loading rod is fixedly connected with the end part of a piston rod of the first mechanical confining pressure controller, and the inner end of the first mechanical confining pressure loading rod is positioned in the pressure chamber; the first mechanical confining pressure loading plate is vertically and fixedly arranged at the inner end of the first mechanical confining pressure loading rod, and the inner side surface of the first mechanical confining pressure loading plate is in contact with a discrete material test.
However, the above patents have the following disadvantages: firstly, the loading mode in the above patent is non-sliding loading, so that gaps are left between loading plates, and the problems of soil squeezing and uneven distribution of stress at the edges of a sample can be caused in the loading process.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a rigid-flexible composite true triaxial loading device for testing the mechanical property of rock and soil.
The invention provides a rigid-flexible composite true triaxial loading device for a rubber film coated loading plate, which comprises: a slide loading member and a rubber film; wherein,
the sliding load member comprises four rigid load plates; the four rigid loading plates are respectively provided with a loading piston, the outer sides of the rigid loading plates are connected with the loading pistons, and the loading pistons apply loads to the rigid loading plates connected with the loading pistons; the four rigid loading plates are respectively overlapped in four directions to form a frame with a central accommodating space, and the central accommodating space of the frame is used for accommodating and clamping rock-soil samples; the four rigid loading plates can slide relative to each other in the horizontal direction and the vertical direction under the action of each loading piston, so that the central accommodating space is reduced after the rock-soil sample is subjected to strain under the action of a load, and the load is ensured to be applied to the rock-soil sample all the time; the sliding loading component comprises four fasteners, the four fasteners are respectively and correspondingly arranged on the outer side of each rigid loading plate, and a combined loading system is formed between the four rigid loading plates and the four fasteners;
the rubber film is wrapped outside the frame and the rock-soil sample and is positioned between the rigid loading plate and the fastener, the rubber film is clamped through the fastener, and therefore the rock-soil sample is sealed,
and the flexible film applies load to the rock-soil sample along the direction vertical to the two sides of the frame.
Preferably, the sliding loading part further comprises four connecting pieces and four sliding blocks;
the four connecting pieces are fixedly connected to the outer sides of the four rigid loading plates respectively and used for transferring load to the rigid loading plates;
the four sliding blocks are respectively arranged between each rigid loading plate and the loading piston, one end of each sliding block is detachably connected with the connecting piece, and the other end of each sliding block is in sliding connection with the loading piston through a sliding bearing, so that the sliding loading plates can freely slide along the direction perpendicular to the connected loading pistons;
it is realized that the four rigid loading plates can slide relative to each other in the horizontal direction and the vertical direction through the four sliding blocks under the action of the loading pistons respectively.
Preferably, the fastener comprises a rectangular plate, two screws are arranged on the rectangular plate, and the inside of the rubber film is in a sealed state by screwing the screws tightly;
the length of the rectangular plate is matched with that of the rigid loading plate, a hole with the same size as the connecting piece is formed in the center of the rectangular plate, and the connecting piece can penetrate through the hole to enable the fastening piece to be sleeved on the connecting piece.
Preferably, the connecting piece is provided with a guide hole, the guide hole is used for connecting a hose for drainage, one end of the hose is connected with the guide hole, and the other end of the hose is connected with the outside.
Preferably, the rigid loading plate is provided with water seepage holes for discharging water in the rock-soil sample, so that the water in the rock-soil sample flows into the connecting piece through the water seepage holes and then is discharged to the outside through the guide holes.
Preferably, the loading device further comprises four stress sensors and four displacement sensors,
the four stress sensors are respectively fixedly connected to the loading piston and used for sensing the load of the loading device acting on the rock-soil sample;
and the displacement sensor is used for sensing the strain of the rock-soil sample under the action of the load.
Preferably, the loading device further comprises a sample loading part, and the sample loading part comprises a fixing plate and a sample loading frame;
the sample loading frame comprises a first cross beam and a second cross beam, and a guide rail is formed by the first cross beam and the second cross beam;
the bottom of the fixing plate is provided with a first groove and a second groove;
the fixed plate is provided with a U-shaped groove which is used for clamping the sliding loading part;
the fixing plate is arranged on the sample loading frame, and the first groove and the second groove of the fixing plate are respectively clamped on the first cross beam and the second cross beam, so that the fixing plate can slide along the direction of the guide rail.
Preferably, the loading piston is driven by a motor system.
Preferably, the rock-soil sample and four rigid loading plates are encapsulated in the flexible rubber film to form a cube shape.
Compared with the prior art, the invention has at least one of the following beneficial effects:
in the structure, four rigid sliding plates and flexible films are adopted to load stress, so that the defect that only rigid loading plates and only flexible films are used for loading is overcome.
In the structure, the rigid loading plate and the rock-soil sample are wholly sealed in the accommodating space by the rubber film and are sealed by the fasteners, so that the conventional structure is changed (the rigid loading plate is arranged outside the rubber film in the conventional structure), and the comprehensive stress path test is realized by changing the arrangement position of the rubber film. In contrast, in the prior art, a rubber film of a general composite true triaxial apparatus can only wrap a soil sample of rock and soil, a rigid loading plate is arranged outside the rubber film, and the stress applied to the soil sample by a horizontal rigid plate is equal to the sum of the water pressure of a pressure chamber and the pressure of the rigid loading plate and cannot be smaller than the water pressure in a confining pressure chamber, so that any Lode angle test of 0-360 degrees cannot be performed. The loading device designed by the invention skillfully designs the rubber film on the rigid loading plate, applies load through the loading piston connected with the rigid loading plate, can directly measure pore water pressure, can realize that the pressure of the soil sample in the direction is smaller than the water pressure in the confining pressure chamber during shearing, and can perform any Lode angle test of 0-360 degrees.
Furthermore, the sliding block is arranged between the loading piston and the rigid loading plate, so that the piston is always positioned at the central position of the deformed central accommodating space, the load can be ensured to be applied to the central position of the rock soil sample, and the uniform distribution of the internal stress of the rock soil is ensured.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a vertical cross-sectional view of the structural principle of the rigid-flexible composite true triaxial loading device according to an embodiment of the present invention;
FIG. 2a is an elevation view of a second rigid load plate in accordance with an embodiment of the present invention;
FIG. 2b is a side view of a second rigid load plate in accordance with an embodiment of the present invention;
FIG. 2c is a top view of a second rigid load plate in accordance with an embodiment of the present invention;
FIG. 3a is a front view of a fixing plate according to an embodiment of the present invention;
FIG. 3b is a side view of a retaining plate according to an embodiment of the present invention;
FIG. 3c is a bottom view of the fixing plate according to an embodiment of the present invention;
FIG. 4a is a front view of a sample rack in an embodiment of the present invention;
FIG. 4b is a side view of a sample rack in an embodiment of the present invention;
FIG. 4c is a top view of a sample rack in accordance with one embodiment of the present invention;
FIG. 5a is a front view of a sample presentation member according to an embodiment of the present invention;
FIG. 5b is a side view of a sample presentation member according to an embodiment of the present invention;
FIG. 5c is a top view of a sample presentation member according to an embodiment of the present invention;
FIG. 6a is an elevation view of the loading process of a loading unit according to an embodiment of the present invention;
FIG. 6b is a side view of the loading process of the loading unit according to an embodiment of the present invention;
FIG. 6c is a bottom view of the loading process of the loading member according to one embodiment of the present invention;
FIG. 7 is a perspective view of a sample loading member in an embodiment of the present invention;
FIG. 8 is a perspective view of a loading process of a loading member in an embodiment of the present invention;
the scores in the figure are indicated as: the rock-soil test sample 10, the test chamber 20, the sliding loading component 30, the first guide hole 41, the second guide hole 42, the first hose 43, the second hose 44, the first water seepage hole 45, the second water seepage hole 46, the fixing plate 51, the sample rack 52, the first rigid loading plate 301, the second rigid loading plate 302, the third rigid loading plate 303, the fourth rigid loading plate 304, the first fastener 305, the second fastener 306, the third fastener 307, the fourth fastener 308, the first connecting piece 309, the second connecting piece 310, the third connecting piece 311, the fourth connecting piece 312, the first sliding block 313, the second sliding block 314, the third sliding block 315, the fourth sliding block 316, the first stress sensor 317, the second stress sensor 318, the third stress sensor 319, the fourth stress sensor 320, the first loading piston 321, the second loading piston 322, the third loading piston 323, the fourth loading piston 324, the first screw 325, 325, A second screw 326, a first groove 511, a second groove 512, a first U-shaped groove 513, a second U-shaped groove 514, a third U-shaped groove 515, a first beam 521, and a second beam 522.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
Referring to fig. 1, a schematic structural diagram of a rigid-flexible composite true triaxial loading device for wrapping a loading plate with a rubber film according to an embodiment of the present invention is shown, including a sliding loading part 30 and a rubber film; wherein the sliding loading member 30 comprises four rigid loading plates. The four rigid loading plates are respectively a first rigid loading plate 301, a second rigid loading plate 302, a third rigid loading plate 303 and a fourth rigid loading plate 304, the four rigid loading plates are overlapped in a manner of being capable of sliding relative to each other to form a frame with a central accommodating space, and the central accommodating space formed by the four rigid loading plates is used for accommodating the rock soil sample 10, so that the rock soil sample 10 is clamped among the four rigid loading plates. In particular, the lower end of third rigid load plate 303 is positioned above the upper surface of fourth rigid load plate 304 and the other end is suspended so that third rigid load plate 303 can slide along the upper surface of load plate 304. The remaining rigid load plates are overlapped in sequence in the same manner. The four rigid loading plates include two vertical plates and two horizontal plates, the second rigid loading plate 302 and the fourth rigid loading plate 304 are vertical plates for applying a load in a vertical direction to the rock and soil sample 10, and the first rigid loading plate 301 and the third rigid loading plate 303 are horizontal plates for applying a load in a horizontal direction to the rock and soil sample 10.
Referring to fig. 1, the sliding loading unit 30 further includes loading pistons respectively acting on the four rigid loading plates, and the four loading pistons are respectively connected to intermediate positions of the four rigid loading plates such that the loading pistons apply loads to the rigid loading plates connected thereto. The four loading pistons are a first loading piston 321, a second loading piston 322, a third loading piston 323, and a fourth loading piston 324, respectively. Preferably, the four loading pistons are driven by an electric motor system. The four rigid loading plates are respectively and correspondingly connected with one loading piston, namely the first loading piston 321 is connected with the first rigid loading plate 301, and the first loading piston 321 applies load to the first rigid loading plate 301; a second loading piston 322 is coupled to the second rigid load plate 302, the second loading piston 322 applying a load to the second rigid load plate 302; the third loading piston 323 is connected to the third rigid loading plate 303, the third loading piston 323 applying a load to the third rigid loading plate 303; the fourth loading piston 324 is coupled to the fourth rigid load plate 304 and the fourth loading piston 324 applies a load to the fourth rigid load plate 304.
The four rigid loading plates are overlapped in a mode that the four rigid loading plates are overlapped in four directions to form a frame with a central containing space in an overlapping mode, so that the four rigid loading plates can slide in the horizontal direction and the vertical direction under the action of the loading piston, and the central containing space is reduced along with the strain of the rock soil sample 10 under the action of the load, so that the load is always exerted on the rock soil sample 10.
The sliding loading part 30 comprises four fasteners, namely a first fastener 305, a second fastener 306, a third fastener 307 and a fourth fastener 308, wherein the four fasteners are respectively correspondingly arranged at the outer side of each rigid loading plate and fixedly connected with each rigid loading plate, and the four fasteners are positioned at the outer side of the rubber film. That is, the first fastener 305 is disposed on the outside of the first rigid load plate 301, the second fastener 306 is disposed on the outside of the second rigid load plate 302, the third fastener 307 is disposed on the outside of the third rigid load plate 303, and the fourth fastener 308 is disposed on the outside of the fourth rigid load plate 304, such that a combined loading system is formed by the four rigid load plates and the four fasteners.
And the rubber film is wrapped outside the four rigid loading plates and the rock soil sample 10 and is positioned between the rigid loading plates and the fasteners, and the rubber film is clamped through the fasteners, so that the rock soil sample 10 is sealed. Thereby encapsulating the soil test sample 10 and the four rigid loading plates in a cubic rubber film (not shown in the drawings) to also form a cubic shape, so that the soil test sample 10 is held by the sliding loading part 30. The flexible thin film applies a load to the rock-soil sample 10 in a direction perpendicular to both sides of the frame, so that the load (flexible load) is applied by water pressure, which directly acts on the rubber thin film in the other two directions, in the other two directions where the rigid loading plate is not provided. In practice, the loading device is placed in the test chamber 20, and the experiment is performed in the test chamber 20, and the test chamber 20 is filled with water during the experiment, so as to apply water pressure (i.e., flexible load) in the other two directions.
In other preferred embodiments, each fastener comprises a rectangular plate on which two screws, shown in fig. 3a as a first screw 325 and a second screw 326, are disposed, and the inside of the rubber film is in a sealed state by tightening the first screw 325 and the second screw 326. The length of the rectangular plate is matched with that of the rigid loading plate, a hole with the same size as the connecting piece is formed in the center of the rectangular plate, and the connecting piece can penetrate through the hole, so that the fastening piece can be just sleeved on the connecting piece.
In other preferred embodiments, in order to ensure that the loading pistons 321, 322, 323 and 324 still act on the central position of the geotechnical specimen 10 after the four rigid loading plates slide, thereby ensuring uniform stress of the geotechnical specimen 10, the four loading pistons are slidably connected with the four rigid loading plates through sliding blocks. The sliding loading unit 30 further includes four connecting members and four sliding blocks, and the connecting members are detachably connected to the sliding blocks. In order to facilitate the connection between the sliding blocks and the rigid loading plate, threads may be provided at the other ends of the first connecting member 309, the second connecting member 310, the third connecting member 311, and the fourth connecting member 312, and the first sliding block 313, the second sliding block 314, the third sliding block 315, and the fourth sliding block 316 may be connected by nuts. The connecting piece is separated from the sliding block in the sample loading process, and the connecting piece is fixedly connected with the sliding block together to transfer load through screwing the screw between the sliding block and the connecting piece after sample loading is finished. Due to the existence of the sliding block, the sliding loading plates can slide relative to each other in the horizontal direction and the vertical direction under the action of the loading piston.
Referring to fig. 1, one end of each of the first connection member 309, the second connection member 310, the third connection member 311, and the fourth connection member 312 is fixedly connected to the outer sides of the first rigid loading plate 301, the second rigid loading plate 302, the third rigid loading plate 303, and the fourth rigid loading plate 304, respectively, for transmitting a load to the rigid loading plates.
The first sliding block 313 is arranged between the first rigid loading plate 301 and the first loading piston 321, the first loading piston 321 and the first sliding block 313 are in sliding connection through a sliding bearing, and the first sliding block 313 is fixedly connected with the first rigid loading plate 301 through a first connecting piece 309; referring to fig. 2a, 2b and 2c, the second sliding block 314 is disposed between the second rigid loading plate 302 and the second loading piston 322, the second loading piston 322 and the second sliding block 314 are slidably connected through a sliding bearing, and the second sliding block 314 is fixedly connected to the second rigid loading plate 302 through the second connecting member 310; the third sliding block 315 is disposed between the third rigid loading plate 303 and the third loading piston 323, the third loading piston 323 and the third sliding block 315 are slidably connected through a sliding bearing, and the third sliding block 315 is fixedly connected to the third rigid loading plate 303 through a third connecting member 311; the fourth sliding block 316 is disposed between the fourth rigid loading plate 304 and the fourth loading piston 324, the fourth loading piston 324 and the fourth sliding block 316 are slidably connected through a sliding bearing, and the fourth sliding block 316 is fixedly connected to the fourth rigid loading plate 304 through a fourth connecting member 312. In the specific implementation process, each connecting piece and each sliding block are separated in the sample loading process, and after the sample loading is finished, the connecting pieces and the sliding blocks are fixedly connected together through screwing screws between the sliding blocks and the connecting pieces to transmit loads.
In the embodiment, the four loading pistons are slidably connected with the four rigid loading plates through the sliding blocks, so that the four loading pistons still act on the central position of the rock soil sample 10 after the four rigid loading plates slide, and the uniform stress of the rock soil sample 10 is ensured, wherein each sliding block is fixedly connected with each rigid loading plate and is slidably connected with the loading piston along the strain direction of the rock soil sample 10. Therefore, after the rock soil sample 10 is strained and the rigid loading plate slides, the sliding block slides to drive the connecting piece and the rigid loading plate to slide, so that the force transmitted by the loading piston is always positioned in the central position of the deformed central accommodating space, the load can be guaranteed to be applied to the central position of the rock soil sample 10, and uniform distribution of the interior of the rock soil is guaranteed.
In some other embodiments, the loading device further comprises a stress sensor and a displacement sensor. And the stress sensor is used for sensing the load of the loading device on the rock soil sample 10. And the displacement sensor is used for sensing the strain of the rock soil sample 10 under the action of the load.
In order to measure the load applied to each of the first, second, third and fourth loading pistons 321, 322, 323 and 324 to the first, second, third and fourth rigid loading plates 301, 302, 303 and 304, a first stress sensor 317, a second stress sensor 318, a third stress sensor 319 and a fourth stress sensor 320 are disposed inside the test chamber 20, and the first stress sensor 317, the second stress sensor 318, the third stress sensor 319 and the fourth stress sensor 320 are all in the shape of a ring and are respectively fixed to the first, second, third and fourth loading pistons 321, 322, 323 and 320, and two of them are fixed to the loading piston in the direction of applying the horizontal load and the other two are located in the direction of applying the vertical load.
In addition, in order to measure the strain of the geotechnical specimen 10 under load, displacement sensors (not shown) are respectively disposed on the second and fourth loading pistons 322 and 324 to measure the displacement in the vertical direction. The other two horizontal first and third loading pistons 321 and 323 are used for applying horizontal pressure, and a displacement sensor (not shown) is also provided for measuring horizontal displacement.
In other preferred embodiments, the slide loading unit 30 can be adjusted appropriately for a particular test protocol. For example, the first and second water seepage holes 45 and 46 are respectively opened on the rigid loading plates acting in the upper and lower directions (the direction of applying a vertical load) of the closed rock-soil sample 10, that is, on the second and fourth rigid loading plates 302 and 304, and water in the rock-soil sample 10 is drained into the second and fourth connectors 310 and 312 through the first and second water seepage holes 45 and 46. The second connector 310 and the fourth connector 312 are respectively provided with a conduit for connecting a water penetration hole and a guide hole, and water entering from the water penetration hole is connected to the outside of the test chamber 20 through the second connector 310, the first guide hole 41 and the second guide hole 42 of the fourth connector 312, and the plastic first hose 43 and the plastic second hose 44 connected to the first guide hole 41 and the second guide hole 42. The plastic first and second hoses 43 and 44 can be used to measure drainage in a drainage shear test or to measure the pressure of water in a non-drainage test.
In other preferred embodiments, as shown in fig. 5a, 5b, 5c and 7, the loading device further includes a sample loading component, the sample loading component includes a fixing plate 51 and a sample loading frame 52, the fixing plate 51 is disposed on the sample loading frame 52, and two grooves, namely a first groove 511 and a second groove 512, are disposed at the bottom of the fixing plate 51 and are used for clamping the sample loading frame 52.
Referring to fig. 4a, 4b and 4c, the sample rack 52 includes a first beam 521 and a second beam 522, which form a guide rail; the fixing plate 51 is placed on the sample loading frame 52, and the first groove 511 and the second groove 512 of the fixing plate 51 are respectively clamped on the first beam 521 and the second beam 522, so that the fixing plate 51 can slide along the direction of the guide rail, and the bottom end of the sample loading frame 52 extends into the three-axis chamber.
Referring to fig. 3a, 3b and 3c, the fixing plate 51 is provided with three U-shaped grooves, namely a first U-shaped groove 513, a second U-shaped groove 514 and a third U-shaped groove 515, for engaging with the sliding loading member 30. In concrete implementation, as shown in fig. 6a, 6b, 6c and 8, when the sample is loaded, the fourth rigid loading plate 304 positioned at the lower portion is placed on the fixed plate 51, the fourth connecting member 312 connected to the fourth rigid loading plate 304 at the lower portion is fastened to the fixed plate 51 through the first U-shaped groove 513 formed in the fixed plate 51, and the first screw 325 and the second screw 326 are fastened to the second U-shaped groove 514 and the third U-shaped groove 515, respectively. The first rigid loading plate 301, the second rigid loading plate 302, the third rigid loading plate 303 and the fourth rigid loading plate 304 in four directions are overlapped on the rock-soil test sample 10 and are mounted on the fixing plate 51. The rock soil sample 10 and the loading plate are conveyed into the triaxial chamber through the sliding fixing plate 51, and then the sample loading is completed through screwing screws on the connecting piece and the sliding block.
In the embodiment, the sample loading process needs to be carried out by an external sample loading device as a support, the sample loading is carried out on the external sample loading device, and after the sample is sealed, the sample is sent into the test chamber through the sample loading device and then is connected with the sliding devices in four directions. The whole formed by the rigid loading plate, the connecting piece and the fastening piece can accurately enter a test room and can be accurately connected with the sliding device.
The loading device of the embodiment uses four rigid loading plates and flexible films to load stress, so that the defect that only the rigid plates and only the flexible films are used for loading is overcome. Meanwhile, the loading device skillfully designs the rubber film outside the rigid loading plate, applies load through the loading piston connected with the rigid loading plate, can directly measure pore water pressure, can realize that the pressure of the soil sample in the direction is smaller than the water pressure in the confining pressure chamber during shearing, and can perform any Lode angle test of 0-360 degrees. Sig1(σ) when Lord angle takes different values from 0 to 360 during shearing1) Refers to the vertical oriented rigid plate pressure, sig2(σ)2) Refers to the magnitude of water pressure, Sig3(σ) in the confining pressure chamber3) Refers to the horizontal stiffness plate pressure, sig2(σ)2)、sig3(σ3) Is equal to sig1(σ)1) Related to the magnitude of change of sig2(σ)2) And sig3(σ)3) Are all followed by sig1(σ)1) The change of (a) is changed, but the change law corresponding to different lored angles is different, for example: the stress in each direction at the initial stage of shearing is taken as 100kPa, and the stress change in shearing under different Lord angles is as follows: when 0 degree Lord angle is taken: sig1(σ)1) If +50kPa, Sig2(σ)2) 25kPa, Sig3(σ)3) -25 kPa; when the angle of Lord of 30 degrees is taken: sig1(σ)1) If +50kPa, Sig2(σ)2) Then unchanged, Sig3(σ)3) Then-50 kPa; when getting60 degree Lord angle: sig1(σ)1) If +50kPa, Sig2(σ)2) Then +50kPa, Sig3(σ)3) -100 kPa; it can be found that at some Lord angle (e.g., 60 degrees), the magnitude of the water pressure in the confining chamber (sig2(σ)2) 100+ 50-150 kPa is the horizontal stiffness plate pressure (sig3(σ)3) 100-. Like the rubber membrane of the ordinary composite true triaxial apparatus can only wrap the soil sample, and the rigid plate is arranged outside the rubber membrane, so that the stress applied on the soil sample by the rigid plate in the horizontal direction is equal to the sum of the water pressure in the pressure chamber and the pressure of the rigid plate, and cannot be smaller than the water pressure in the confining pressure chamber. However, in the embodiment, the rigid loading plate is wrapped in the rubber membrane by the loading device, so that the pressure of the soil sample in the direction is smaller than the water pressure value in the confining pressure chamber during shearing, and a test at any Lord angle of 0-360 degrees can be performed.
The present invention has been described above by way of example only, and is not limited thereto. The scope of protection of the invention is therefore determined by the claims that follow.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (9)
1. The utility model provides a real triaxial loading device of just gentle complex of rubber film outsourcing loading plate which characterized in that: the method comprises the following steps: a slide loading member and a rubber film; wherein,
the sliding load member comprises four rigid load plates; the four rigid loading plates are respectively provided with a loading piston, the outer sides of the rigid loading plates are connected with the loading pistons, and the loading pistons apply loads to the rigid loading plates connected with the loading pistons; the four rigid loading plates are respectively overlapped in four directions to form a frame with a central accommodating space, and the central accommodating space of the frame is used for accommodating and clamping rock-soil samples; the four rigid loading plates can slide relative to each other in the horizontal direction and the vertical direction under the action of each loading piston, so that the central accommodating space is reduced after the rock-soil sample is subjected to strain under the action of a load, and the load is ensured to be applied to the rock-soil sample all the time; the sliding loading component comprises four fasteners, the four fasteners are respectively and correspondingly arranged on the outer side of each rigid loading plate, and a combined loading system is formed between the four rigid loading plates and the four fasteners;
the rubber film is wrapped outside the frame and the rock-soil sample and is positioned between the rigid loading plate and the fastening piece, the rubber film is clamped through the fastening piece, so that the rock-soil sample is sealed, and the flexible film applies loads to the rock-soil sample along the direction perpendicular to the two sides of the frame.
2. The rigid-flexible composite true triaxial loading device of a rubber film outer wrapping loading plate according to claim 1, wherein: the sliding loading part also comprises four connecting pieces and four sliding blocks;
the four connecting pieces are fixedly connected to the outer sides of the four rigid loading plates respectively and used for transferring load to the rigid loading plates;
the four sliding blocks are respectively arranged between each rigid loading plate and the loading piston, one end of each sliding block is detachably connected with the connecting piece, and the other end of each sliding block is in sliding connection with the loading piston through a sliding bearing, so that the sliding loading plates can freely slide along the direction perpendicular to the connected loading pistons;
it is realized that the four rigid loading plates can slide relative to each other in the horizontal direction and the vertical direction through the four sliding blocks under the action of the loading pistons respectively.
3. The rigid-flexible composite true triaxial loading device of a rubber film outer wrapping loading plate according to claim 2, wherein: the fastener comprises a rectangular plate, two screws are arranged on the rectangular plate, and the interior of the rubber film is in a sealed state by screwing the screws tightly;
the length of the rectangular plate is matched with that of the rigid loading plate, a hole with the same size as the connecting piece is formed in the center of the rectangular plate, and the connecting piece can penetrate through the hole to enable the fastening piece to be sleeved on the connecting piece.
4. The rigid-flexible composite true triaxial loading device of a rubber film outer wrapping loading plate according to claim 2, wherein: the connecting piece is provided with a guide hole, the guide hole is used for connecting a hose for drainage, one end of the hose is connected with the guide hole, and the other end of the hose is connected with the outside.
5. The rigid-flexible composite true triaxial loading device of a rubber film outer wrapping loading plate according to claim 4, wherein: and the rigid loading plate is provided with water seepage holes for discharging water in the rock-soil sample, so that the water in the rock-soil sample flows into the connecting piece through the water seepage holes and then is discharged to the outside through the guide holes.
6. The rigid-flexible composite true triaxial loading device of a rubber film outer wrapping loading plate according to claim 1, wherein: the loading device further comprises four stress sensors and four displacement sensors,
the four stress sensors are respectively fixedly connected to the loading piston and used for sensing the load of the loading device acting on the rock-soil sample;
and the displacement sensor is used for sensing the strain of the rock-soil sample under the action of the load.
7. The rigid-flexible composite true triaxial loading device of a rubber film outer wrapping loading plate according to claim 1, wherein: the loading device also comprises a sample loading component, and the sample loading component comprises a fixing plate and a sample loading frame;
the sample loading frame comprises a first cross beam and a second cross beam, and a guide rail is formed by the first cross beam and the second cross beam;
the bottom of the fixing plate is provided with a first groove and a second groove;
the fixed plate is provided with a U-shaped groove which is used for clamping the sliding loading part;
the fixing plate is arranged on the sample loading frame, and the first groove and the second groove of the fixing plate are respectively clamped on the first cross beam and the second cross beam, so that the fixing plate can slide along the direction of the guide rail.
8. The rigid-flexible composite true triaxial loading device of a rubber film overwrap loading plate according to any one of claims 1 to 7, wherein: the loading piston is driven by a motor system.
9. The rigid-flexible composite true triaxial loading device of a rubber film overwrap loading plate according to any one of claims 1 to 7, wherein: the rock-soil sample and the four rigid loading plates are packaged in the flexible rubber film to form a cube.
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| CN201911380874.3A CN110987642A (en) | 2019-12-27 | 2019-12-27 | Rigid-flexible composite true triaxial loading device of rubber film outer wrapping loading plate |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112014228A (en) * | 2020-09-02 | 2020-12-01 | 中国矿业大学 | Rigid-flexible type true triaxial grouting seepage coupling test device and method for CT scanning |
| CN116735378A (en) * | 2023-05-29 | 2023-09-12 | 广州建筑股份有限公司 | Device and method for testing along-drilling follow pipe pile side grouting shear model |
-
2019
- 2019-12-27 CN CN201911380874.3A patent/CN110987642A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112014228A (en) * | 2020-09-02 | 2020-12-01 | 中国矿业大学 | Rigid-flexible type true triaxial grouting seepage coupling test device and method for CT scanning |
| CN116735378A (en) * | 2023-05-29 | 2023-09-12 | 广州建筑股份有限公司 | Device and method for testing along-drilling follow pipe pile side grouting shear model |
| CN116735378B (en) * | 2023-05-29 | 2024-04-16 | 广州建筑股份有限公司 | Device and method for testing along-drilling follow pipe pile side grouting shear model |
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