CN115575316A - Visual test device and method for shear performance of cast-in-place concrete member and soil interface - Google Patents
Visual test device and method for shear performance of cast-in-place concrete member and soil interface Download PDFInfo
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- CN115575316A CN115575316A CN202211231973.7A CN202211231973A CN115575316A CN 115575316 A CN115575316 A CN 115575316A CN 202211231973 A CN202211231973 A CN 202211231973A CN 115575316 A CN115575316 A CN 115575316A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N19/00—Investigating materials by mechanical methods
- G01N19/04—Measuring adhesive force between materials, e.g. of sealing tape, of coating
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N19/00—Investigating materials by mechanical methods
- G01N19/02—Measuring coefficient of friction between materials
Abstract
The invention discloses a visual test device and a test method for shear performance of a cast-in-place concrete member and a soil interface, wherein a test platform, a soil body container tank, a displacement monitoring device, a concrete member traction control box, a counterweight balance frame, a horizontal traction device, a liftable pulley device and the like are adopted, the relation between the concrete member and the soil interface is tested in the actual construction of the cast-in-place concrete, the area of the cast-in-place concrete and the soil interface is kept unchanged in the whole test process, and the real-time observation and recording of the interface friction state are realized; the invention can be used for researching the friction between the concrete pile and the soil interface, can also be used for researching the friction between the underground concrete structure and the soil interface, and can also be used for researching the mechanical characteristics between the cast-in-place concrete member and the interfaces of other materials such as concrete materials, geotextiles and the like.
Description
Technical Field
The invention relates to the technical field of testing of shearing performance and mechanical performance of an interface of a cast-in-place concrete member and a soil body, in particular to a simple visual testing device and method for the shearing performance of the interface of the cast-in-place concrete member and the soil body.
Background
In the cast-in-place concrete engineering, the characteristics of the interface between the cast-in-place concrete member and the soil body are a key technical index, and the stability of the whole engineering can be directly influenced. At present, a test device for testing the interface friction performance between a cast-in-place concrete member and a soil body has no clear specification or standard, so that the device, the component and the design mode in the invention cannot obtain the reference of the relevant specification standard. The existing interface friction test instrument has the following defects:
(1) The existing interface friction test is not a visual test device (for example, CN114993855a discloses a ring shear test device and method for researching friction characteristics of a pile-cement soil contact surface), only the corresponding relation between force and displacement can be obtained, a test block can be taken out for checking after the test is finished, and the interface friction characteristics cannot be observed in real time in the test process.
(2) The existing interface friction test usually adopts a prefabricated concrete member, and the prefabricated concrete member is completely separated from the soil interface, which is different from cast-in-place concrete in actual engineering.
(3) In the existing interface friction test, a counter-force device (such as a device disclosed in CN203191265U and applied to an indoor medium-sized shear test) is adopted for applying overlaying load, and the size of a shear surface can be changed in the whole shearing process, so that the test result is influenced.
Disclosure of Invention
Aiming at the technical problems, the invention provides a visual test device and a visual test method for the shearing performance of the interface between a cast-in-place concrete member and soil.
In order to achieve the above purpose, the invention provides the following technical scheme:
the utility model provides a visual test device of cast in situ concrete member and soil interface shear behavior, includes:
the test platform is used for placing a soil body container groove, a cast-in-place mould, a counterweight balance frame, a horizontal traction device and a traction force generation device;
the soil body container groove is fixed at one end of the test platform and is used for containing a test soil body; a concrete member traction control box is placed in the soil body container groove, a hole for a traction rope to pass through is reserved in the front side of the soil body container groove, and a displacement monitoring device is installed on the rear side of the soil body container groove and used for monitoring the horizontal displacement of the concrete member traction control box;
the concrete member traction control box is sleeved on the concrete member from top to bottom and is used for applying horizontal tension to the concrete member; the concrete member is formed by pouring concrete into the cast-in-place mould;
the counterweight balancing stand is used for providing vertical load for the concrete member and keeping the balance of two sides;
the horizontal traction device is used for applying horizontal tension to the concrete member and the traction control box and adjusting the height through the liftable pulley device;
the traction force generating device is used for providing traction force for the horizontal traction device and controlling the flow of sand in the quicksand pipeline through the flow speed control device;
the cast-in-place mould is used for being inserted into the soil layer of the soil body container groove by 1-3mm and pouring concrete into the cast-in-place mould;
and the digital camera is placed on one side of the test platform and is used for observing the horizontal movement condition of the concrete poured in the soil container groove.
Furthermore, the test platform comprises a test platform main body and a platform height adjusting device, the platform height adjusting device comprises a support sleeve, a lifting rotating ring, a threaded column and a pile bottom cushion block, the upper end of the support sleeve is connected with the bottom of the test platform main body, the lower end of the support sleeve is connected with the threaded column through the lifting rotating ring, the upper end of the threaded column moves inside the lower end of the support sleeve, and the lower end of the threaded column is connected with the pile bottom cushion block; the lifting rotating ring comprises a rotating handle and a supporting ring, and threads matched with the threaded columns are arranged inside the supporting ring.
Furthermore, the soil body container groove is a container groove formed by enclosing three steel plates and toughened glass; the three steel plates are integrated and fixed on the test platform, and a hole for the traction rope to pass through is reserved in the front side of the test platform; the toughened glass is positioned on the side surface and movably connected in the groove tracks of the three steel plates.
Further, displacement monitoring devices includes magnetism and inhales support, hinge bracket and digital display percentage table, and magnetism is inhaled the support and is fixed on test platform, and the support is inhaled through hinge bracket connection magnetism to digital display percentage table.
Furthermore, the concrete member traction control box comprises a traction control box body, a balance weight balance frame pin is arranged at the center of the top of the traction control box body, a traction rope hook is arranged on the front side of the traction control box body, and the height of the traction control box body is 2/3 times of the height of the concrete member and is smaller than 1 time.
Furthermore, the counterweight balance frame consists of 2 counterweight frames, a counterweight block support and a plurality of cow-hoof-shaped counterweight blocks, the upper ends of the 2 counterweight frames are connected in a matched manner to form an upper end connecting hole for inserting a counterweight balance frame pin at the top of the traction control box, and the lower ends of the 2 counterweight frames are connected in a matched manner to form a lower end connecting hole for inserting a threaded rod piece of the counterweight block support; the balancing weight support comprises a nut, a threaded rod piece and a bottom support, the threaded rod piece is upwards inserted into the lower end connecting hole and then screwed and fixed through the nut, and the bottom support is used for placing the cow hoof type balancing weight.
Further, horizontal draw gear includes haulage rope, pulley, digital display spring balance and sand storage container, and the haulage rope couple of concrete member traction control case is connected to the one end of haulage rope, and the upper end of connecting the digital display spring balance behind the pulley is walked around to the other end of haulage rope, and the haulage rope that the lower extreme of digital display spring balance is connected passes and connects sand storage container behind the horizontal draw gear hole that test platform reserved.
Furthermore, the lifting pulley device comprises a pulley pillar inclined strut, a pulley fixing sleeve, a rotating ring, a lifting threaded column and a lifting pulley pillar; the lower end of the lifting pulley pillar is fixed on the test platform, and the upper end of the lifting pulley pillar is connected with the lifting threaded column; two ends of the pulley strut inclined strut are respectively fixed on the test platform and the lifting pulley strut and are used for supporting the lifting pulley strut to keep the lifting pulley strut vertical; the pulley fixing sleeve is connected to the upper end of the lifting threaded column through a rotating ring; an internal thread matched with the lifting threaded column is formed inside the rotating ring, and a rotating handle is arranged outside the rotating ring; the pulley is connected between the two pulley fixing sleeves in a rotating mode.
Further, the traction force generating device comprises an hourglass, a flow speed control device, an hourglass bracket and a quicksand slide; the hourglass is fixed on the test platform through the hourglass support, and the lower end of the hourglass is connected with the quicksand slide through the flow speed control device; the quicksand slide passes through a quicksand slide hole reserved on the test platform and is connected with a sand storage container of the horizontal traction device; the flow velocity control device comprises a quicksand pipeline, a valve support frame, a valve baffle, a support spring, a threaded rod and a rotary handle; the top of the quicksand pipeline is connected with the bottom of the hourglass, the bottom of the quicksand pipeline is connected with the quicksand slideway, and a notch matched with the valve baffle is formed in the middle of the quicksand pipeline; the valve support frame is fixed on one side of the quicksand pipeline and used for supporting the valve baffle; one end of the threaded rod penetrates through a screw hole of the valve support frame to be connected with the rotating handle, and the other end of the threaded rod faces towards the valve blocking piece; the valve blocking piece is partially inserted into the opening of the quicksand pipeline through two supporting springs, and the two supporting springs are connected between the valve blocking piece and the valve supporting frame and are respectively positioned at two sides of the threaded rod; the inserted part of the valve retaining piece is arc-shaped, the diameter of the inserted part is the same as that of the hollow circular ring on the inner wall of the quicksand pipeline, and the inserted part is used for adjusting the falling flow of sand.
On the other hand, the invention also provides a method for testing the friction characteristic of the rib-soil interface, which adopts the device of any one of the above steps:
s1, pouring concrete by adopting a cast-in-place mould, removing the cast-in-place mould after a concrete member is manufactured, and sleeving a traction control box of the concrete member on the concrete member from top to bottom;
s2, mounting the balance weight balance frame on a traction control box, and placing a Niu Tixing balance weight block according to test requirements;
s3, resetting a digital display dial indicator in the displacement monitoring device, and recording the reading on a digital display spring scale in the horizontal traction device; opening a hourglass controller in the traction force generation device, adjusting to a proper flow rate, and synchronously recording the readings displayed by the digital display dial indicator and the digital display spring scale in real time;
s4, stopping the test when the concrete member traction control box and the internal concrete member generate continuous sliding under the action of horizontal traction force;
s5, recording the reading and the time displayed by the digital display spring scale to obtain the relation between the horizontal traction force and the time, and recording the digital display dial indicator and the time to obtain the relation between the horizontal displacement and the time of the concrete member traction control box so as to obtain the relation between the horizontal traction force and the horizontal displacement; calculating to obtain a relation curve between the shear stress and the shear displacement under the vertical load, so as to obtain a group of normal stress and ultimate shear stress;
and S6, changing the numerical value of the vertical load by repeating the steps S1-S5 to obtain multiple groups of normal stress and ultimate shear stress, and calculating to obtain multiple indexes of the shear plane.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention adopts the cast-in-place concrete member to restore the mutual permeation relationship and the working state between the concrete member and the soil contact surface in the actual engineering.
(2) In the whole test process, the contact interface area of the cast-in-place concrete member and the soil is always kept unchanged.
(3) The real-time monitoring of the shearing process of the cast-in-place concrete member and the soil interface in the loading process can be realized through the visual test device, the high-speed camera is used for shooting, and the thickness, the stress characteristics, the displacement state and the like of the shear band can be observed and analyzed.
(4) Normal pressure is exerted through the counter weight balancing stand, can simulate under the different load effects, the interface mechanical properties, adopts the vertical loading system of this patent, and vertical loading's pressure size does not have the restriction, simulation actual engineering condition that can be better.
(5) Based on the test requirements for testing the interface friction performance between a cast-in-place concrete member and a soil body, the invention designs a contrast test which can realize different test parameters (the water content, the density and the type of the soil body, the strength of the concrete member, different vertical loads and the like), collects the test results of the static and dynamic friction forces, the dynamic friction force and the relative displacement, the relationship between the normal pressure and the friction force and the like of the interface between the soil body and the concrete member, and further obtains the friction performance index of the interface;
(6) The horizontal traction force of the invention adopts a mode of controlling the hourglass at a constant speed, a valve capable of controlling the flow speed of the hourglass is arranged in the horizontal traction force, the sand can fall at a constant speed, so that the horizontal traction force is uniform.
(7) The invention can be prefabricated in factory, with simple installation and low cost, to improve test efficiency.
In conclusion, the simple visual test device and the test method for the shearing performance of the cast-in-place concrete member and the soil interface provided by the invention have the advantages that the relation between the concrete member and the soil (or other materials) interface in actual construction is realized through the cast-in-place concrete, and the real-time observation and recording of the interface friction state in the whole test process are realized through the visual test device; by applying normal pressure, simulation of different stress states in actual engineering is realized, and by changing the magnitude of the normal pressure, the shear strength index of the interface is finally obtained. The invention can be used for researching the friction between the concrete pile and the soil interface, the friction between the underground concrete structure and the soil interface, and the mechanical properties between the cast-in-place concrete member and the interfaces of the concrete material, the geotextile and the like.
Drawings
In order to more clearly illustrate the embodiments of the present application or technical solutions in the prior art, the drawings required in the embodiments will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained by those skilled in the art according to these drawings.
Fig. 1 is a schematic perspective view of a simple apparatus for visualizing a shear performance of an interface between a cast-in-place concrete member and soil according to an embodiment of the present invention.
Fig. 2 is a schematic perspective view of a test platform according to an embodiment of the present invention.
Fig. 3 is a schematic perspective view of a test bed height adjusting device according to an embodiment of the present invention.
Fig. 4 is a partial schematic view of a test bed height adjusting device provided in an embodiment of the present invention.
Fig. 5 is a first perspective view of a soil body container tank according to an embodiment of the present invention.
Fig. 6 is a second schematic perspective view of a soil body container tank according to an embodiment of the present invention.
Figure 7 is a front view of a soil body receptacle tank provided in accordance with an embodiment of the present invention.
Fig. 8 is a schematic perspective view of a displacement monitoring device according to an embodiment of the present invention.
Fig. 9 is a perspective view of a concrete member and a traction control box according to an embodiment of the present invention.
Fig. 10 is a schematic view of a counterweight balance frame according to an embodiment of the invention.
Fig. 11 is a side view of a counterweight balance frame according to an embodiment of the present invention.
Fig. 12 is an exploded view of a counterweight balance frame according to an embodiment of the present invention.
Fig. 13 is a schematic view of a counterweight block support according to an embodiment of the present invention.
Fig. 14 is a schematic view of a traction device according to an embodiment of the present invention.
Fig. 15 is a schematic perspective view of a liftable pulley apparatus according to an embodiment of the present invention.
Fig. 16 is a front view of a liftable pulley apparatus according to an embodiment of the present invention.
Fig. 17 is a side view of a liftable pulley apparatus according to an embodiment of the present invention.
Fig. 18 is a perspective view of a traction force generation device according to an embodiment of the present invention.
Fig. 19 is a front view of a traction generating device according to an embodiment of the present invention.
Fig. 20 is a perspective view of a flow rate control device according to an embodiment of the present invention.
Fig. 21 is a top view of a cast-in-place mold according to an embodiment of the invention.
Fig. 22 is a perspective view of a cast-in-place mold according to an embodiment of the invention.
Detailed Description
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and examples.
As shown in fig. 1. The invention provides a simple visual test device for shearing performance of a cast-in-place concrete member and a soil interface, which comprises a test platform 1, a soil body container groove 2, a displacement monitoring device 3, a concrete member traction control box 4, a counterweight balance frame 5, a horizontal traction device 6, a liftable pulley device 7, a traction force generation device 8, a cast-in-place mold 9 and a digital camera 10.
(1) Test platform
As shown in fig. 2-4, the test platform 1 is used for placing a soil container groove, a cast-in-place mold, a counterweight balancing stand, a horizontal traction device and a traction force generating device. The test platform 1 comprises a test platform main body 1-1 and a platform height adjusting device. A horizontal traction device hole 1-2 and a quicksand slideway hole 1-3 are reserved on the test platform main body 1-1 and are respectively used for placing a traction rope of a horizontal traction device 6 and a quicksand slideway 8-4. The platform height adjusting device comprises a supporting sleeve 1-4, a lifting rotating ring 1-5, a threaded column 1-6 and a pile bottom cushion block 1-7, wherein the upper end of the supporting sleeve 1-4 is connected with the bottom of a test platform main body 1-1, the lower end of the supporting sleeve 1-4 is connected with the threaded column 1-6 through the lifting rotating ring 1-5, the upper end of the threaded column 1-6 is movably arranged in the lower end of the supporting sleeve 1-4, and the lower end of the threaded column 1-6 is connected with the pile bottom cushion block 1-7 so as to enlarge the contact area and stabilize the platform; the lifting rotating ring 1-5 comprises a rotating handle 1-8 and a supporting ring 1-9, the threaded column can be moved up and down through forward and reverse rotating of the handle, so that the purpose of accurately adjusting the height can be achieved, threads 1-10 matched with the threaded column 1-6 are arranged inside the supporting ring 1-9, a circle of threads is arranged inside the supporting ring, a rotating curve is consistent with external threads of the threaded column 1-6, the height of the threads is close to the distance between the external threads of the threaded column, the threaded column can rotate freely, the strength of a component can be improved, and stable support can be guaranteed to be provided for the supporting sleeve.
(2) Soil body container groove
As shown in fig. 5-7, the soil body container tank 2 is fixed at one end of the test platform 1 and is used for accommodating a test soil body 2-2; concrete member traction control case 4 has been placed to the inside of soil body container groove 2, and the hole that supplies the haulage rope to pass through is reserved to the front side of soil body container groove 2, and displacement monitoring devices 3 for the horizontal displacement of monitoring concrete member traction control case 4 is installed to the rear side of soil body container groove 2.
Specifically, the soil body container groove 2 is a container groove 2-1 which is formed by enclosing three steel plates and toughened glass; the three steel plates are integrated and welded and fixed on the test platform 1, and holes 2-3 for the traction ropes to pass through are reserved in the front side of the test platform; the toughened glass 2-5 is positioned on the side surface and movably connected in the groove tracks 2-4 of the three steel plates. During installation, the toughened glass is vertically and downwards placed in the track to form a soil body container groove which can be conveniently filled with soil and is beneficial to observation.
(3) Displacement monitoring device
As shown in FIG. 8, the displacement monitoring device 3 comprises a magnetic attraction support 3-1, a hinge support 3-2 and a digital display dial indicator 3-3, the magnetic attraction support 3-1 is fixed on the test platform 1, and the digital display dial indicator 3-3 is connected with the magnetic attraction support 3-1 through the hinge support 3-2. The pointer of the 3-3 digital display dial indicator is tightly attached to the outer wall of the traction control box body 4-3, and when the concrete member 4-1 and the traction control box body 4-3 move, the horizontal displacement of the concrete member 4-1 and the traction control box body 4-3 can be obtained through the reading of the digital display dial indicator 3-3.
(4) Concrete member traction control box
As shown in fig. 9, the concrete member traction control box 4 is sleeved on the concrete member 4-1 from top to bottom, and is used for applying a horizontal pulling force to the concrete member; the concrete member 4-1 is formed by pouring concrete into a cast-in-place mold 9. Specifically, the concrete member traction control box 4 comprises a traction control box body 4-3, a balance weight balance frame pin 4-2 is arranged at the center of the top of the traction control box body 4-3, a traction rope hook 4-4 is arranged on the front side of the traction control box body 4-3, the traction control box body 4-3 is sleeved on the concrete member 4-1 during testing and used for conveniently applying horizontal tension to the concrete member 4-1, in order to ensure that the concrete member 4-1 cannot overturn under the action of the horizontal tension, the height of the traction control box body 4-3 is 5/3 times or more of the height of the concrete member 4-1.
(5) Counterweight balancing stand
As shown in fig. 10-13, the counterweight balance frame 5 is composed of 2 counterweight frames 5-1, a counterweight block support 5-2 and a plurality of cow-hoof type counterweight blocks 5-3, and is used for providing vertical load for concrete members, keeping two sides balanced and not affecting the view of an observation surface; the upper ends of the 2 counterweight frames 5-1 are connected in a matching way to form an upper end connecting hole 5-7 for inserting a counterweight balance frame pin 4-2 at the top of the traction control box, and the lower ends of the 2 counterweight frames 5-1 are connected in a matching way to form a lower end connecting hole 5-8 for inserting a threaded rod piece 5-5 of the counterweight block support; the counter weight block support 5-2 comprises a screw cap 5-4, a threaded rod piece 5-5 and a bottom support 5-6, the threaded rod piece 5-5 is upwards inserted into the lower end connecting hole 5-8 and then is screwed and fixed through the screw cap 5-4, and the bottom support 5-6 is used for placing the cow hoof type counter weight block 5-3. According to the test requirement, for different vertical pressures, the process is completed by placing a cow-hoof-shaped balancing weight 5-2 on the upper side of a bottom support 5-6 of the balancing weight support.
(6) Horizontal traction device
As shown in fig. 14, the horizontal traction device 6 comprises a traction rope 6-1, a pulley 6-2, a digital display spring scale 6-3 and a sand storage container 6-4, and is used for applying horizontal tension to the concrete member and the traction control box and adjusting the height through the liftable pulley device 6; the traction rope 6-1 is preferably a steel wire rope or a nylon rope with light self weight and certain strength and toughness. One end of a traction rope 6-1 is connected with a traction rope hook of a concrete member traction control box, the other end of the traction rope 6-1 is connected with the upper end of a digital display spring scale 6-3 after passing around a pulley 6-2, and the traction rope connected with the lower end of the digital display spring scale 6-3 is connected with a sand storage container 6-4 after passing through a horizontal traction device hole reserved in the test platform. Sand is added to the Chu Sha container 6-4, and a horizontal pulling force can be applied to the concrete member 4-1 through the pulling rope 6-1. The digital display spring scale 6-3 can display the weight of the sand in the sand storage container 6-4 in real time, and the horizontal traction force can be obtained through conversion.
(7) Liftable pulley device
As shown in fig. 15-17, the liftable pulley apparatus 7 comprises a pulley post inclined strut 7-1, a pulley fixing sleeve 7-2, a rotating ring 7-4, a liftable threaded post 7-5 and a liftable pulley post 7-3; the lower end of the lifting pulley pillar 7-3 can be fixed on the test platform 1 by welding, and the upper end is connected with the lifting threaded pillar 7-5; two ends of the pulley strut inclined strut 7-1 can be respectively fixed on the test platform 1 and the liftable pulley strut 7-3 by welding, and are used for supporting the liftable pulley strut 7-3 to keep the liftable pulley strut vertical and prevent inclination; the pulley fixing sleeve 7-2 is connected to the upper end of the lifting threaded column 7-5 through a rotating ring 7-4; an internal thread matched with the lifting threaded column 7-5 is formed inside the rotating ring 7-4, and a rotating handle is arranged outside the rotating ring; the pulley 6-2 is rotatably connected between the two pulley fixing sleeves 7-2, and the height of the pulley 6-2 can be controlled by rotating the rotating ring 7-4, so that the traction rope 6-1 is leveled.
(8) Traction force generating device
As shown in fig. 18-20, the traction force generating device 8 comprises an hourglass 8-1, a flow rate control device 8-2, an hourglass support 8-3 and a quicksand slide 8-4, and is used for providing traction force for the horizontal traction device and controlling the flow of sand in the quicksand pipeline through the flow rate control device. Specifically, an hourglass 8-1 is fixed on a test platform 1 through an hourglass support 8-3, and the lower end of the hourglass 8-1 is connected with a quicksand slideway 8-4 through a flow speed control device 8-2; the quicksand slide 8-4 penetrates through a quicksand slide hole 1-3 reserved on the test platform 1 to be connected with a sand storage container of the horizontal traction device, and the top of the quicksand slide 8-4 is welded with the edge of a quicksand slide hole 1-3 reserved; specifically, the flow rate control device 8-2 comprises a quicksand pipeline 8-5, a valve support frame 8-7, a valve baffle 8-6, a support spring 8-11, a threaded rod 8-8 and a rotary handle 8-9; the top of the quicksand pipeline 8-5 is connected with the bottom of the hourglass 8-1, the bottom of the quicksand pipeline 8-5 is connected with the quicksand slideway 8-4, and a notch 8-10 matched with a valve baffle is formed in the middle of the quicksand pipeline 8-5; the valve support frame 8-7 is fixed on one side of the quicksand pipeline 8-5 and is used for supporting the valve baffle plate 8-6; one end of the threaded rod 8-8 penetrates through a screw hole of the valve support frame 8-7 to be connected with the rotary handle 8-9, and the other end of the threaded rod faces towards the valve baffle plate 8-6; the valve baffle plate 8-6 is partially inserted into a gap 8-10 of the quicksand pipeline through two supporting springs 8-11, and the two supporting springs 8-11 are connected between the valve baffle plate 8-6 and the valve supporting frame 8-7 and are respectively positioned at two sides of the threaded rod 8-8; the inserted part of the valve baffle 8-6 is arc-shaped, the diameter of the inserted part is the same as that of the hollow circular ring on the inner wall of the quicksand pipeline, and the inserted part is used for adjusting the falling flow of sand. The front end of the threaded rod 8-8 is only contacted with the valve baffle plate 8-6 but is not connected with the valve baffle plate. The handle 8-9 is rotated clockwise to enable the threaded rod 8-8 to be screwed into the valve supporting frame 8-7, the front end of the threaded rod 8-8 can push the valve baffle 8-6 to move forwards, the handle 8-9 is rotated counterclockwise to enable the threaded rod 8-8 to move outwards, the threaded rod 8-8 does not generate thrust on the valve baffle 8-6, and at the moment, the supporting spring 8-11 pulls the valve baffle 8-6 to move outwards, so that the flow of sand in the sand flowing pipeline 8-5 is controlled.
(9) Cast-in-situ mould
As shown in fig. 21-22, the cast-in-place mold 9 is composed of a turning angle steel plate 9-1 and an L-shaped steel plate 9-2, and is used for being inserted into a soil layer of a soil container groove by 1-3mm and pouring concrete into the soil layer; proper holes are reserved at the joint of the two sides of the corner steel plate 9-1 and the L-shaped steel plate 9-2, and the corner steel plate and the L-shaped steel plate are fixed by bolts 9-3 during installation. When the cast-in-place mould is used, the assembled 9-cast-in-place mould is inserted into a soil layer for 1-3mm, so that the phenomenon of slurry leakage during concrete pouring is prevented.
(10) Digital camera
As shown in fig. 1, a digital camera 10 is disposed at one side of the testing platform for observing the horizontal movement of the concrete poured in the trough of the soil container.
The invention provides a simple visual test method for shear performance of a cast-in-place concrete member and a soil interface, which comprises the following steps of:
preparation before experiment:
(1) Selecting a relatively flat test field before installation, placing the test platform 1 on a flat ground, then adjusting four lifting rotating rings 1-5 below the test platform 1 to enable the test platform 1 to meet the height required by the test, observing the levelness of the test platform 1 by using a horizontal ruler, and ensuring that the test platform 1 is in a horizontal state.
(2) The toughened glass 2-5 is arranged in a groove track 2-4 of a steel plate container 2-1 to form a soil body container 2, then the soil for the test is loaded into the soil body container 2 in a layering mode, layering compaction processing is carried out according to the test design, and the loading of the soil can be stopped when the soil for the test is loaded to the required height.
(3) And assembling a 9-cast-in-place mould, so as to facilitate smooth demoulding after concrete curing, winding preservative films on steel plates at the periphery of the cast-in-place mould 9, placing the preservative films on a soil layer of the soil body container groove 2, wherein the position is close to the rear and is a certain distance away from the steel plates behind the soil body container groove 2, the distance can meet the requirement of placing the displacement monitoring device 3, and the cast-in-place mould 9 is inserted into the soil layer by 1-3mm to prevent bottom slurry leakage during cast-in-place concrete.
(4) Pouring concrete into the cast-in-place mould 9 according to the mix proportion of the concrete members in the test scheme to the required height, stopping pouring, slightly knocking the steel plate of the cast-in-place mould 9 to ensure that the surface of the concrete inside is as flat as possible, then waiting until the surface is hardened, sprinkling water, covering a preservative film, and maintaining for the required time.
(5) And (3) opening the preservative film above the cast-in-place mould 9, then slightly taking out the cast-in-place mould 9, taking out the rest preservative films, and sleeving the concrete member traction control box 4 on the concrete member from top to bottom.
(6) And (3) adsorbing the magnetic suction support in the displacement monitoring device 3 outside the soil body container groove 2 close to one side of the concrete member, connecting the digital display dial indicator and the spherical hinge support, horizontally placing the digital display dial indicator, and tightly attaching the probe of the digital display dial indicator to the concrete member traction control box 4.
(7) After the upper end connecting holes 5-7 at the upper ends of the 2 counterweight frames 5-1 are aligned with the lower end connecting holes 5-8 at the lower ends, the upper end connecting holes 5-7 at the upper ends are inserted into the counterweight balance frame pins 4-2, the lower end connecting holes 5-8 at the lower ends penetrate through the threaded rod pieces 5-5 from bottom to top, and the screw caps 5-4 are screwed.
(8) According to the test design, for different vertical pressures, the cow-hoof type balancing weights 5-2 are placed on the upper side of a bearing disc of a 5-6 balancing weight support, a dial indicator is installed above a concrete member traction control box 4 to measure vertical displacement of the concrete member traction control box 4 and an internal test block under the effect of the vertical pressure, and when the vertical load meets the test design requirements, the load is stopped being applied.
(9) The lifting pulley device 7 is adjusted and the height is adjusted to be kept horizontal with a traction rope hook 4-4 of the concrete member traction control box 4,
(10) One end of a traction rope 6-1 is connected with a traction rope hook 4-4, the other side of the traction rope passes through a reserved hole 2-3 reserved in a soil body container groove 2, extends downwards after passing through a pulley 6-2, is connected with a digital display spring balance 6-3, and is connected with a Chu Sha container 6-4 below the digital display spring balance 6-3.
(11) Installing a traction force generating device 8, putting sand into the hourglass 8-1, and adjusting the position and the angle of the quicksand slide 8-4 to ensure that the quicksand slide just extends above the sand storage container 6-4.
(12) Before the test is started, a digital camera 10 is placed on the observable side of the soil body container groove 2, the digital display dial indicator 3-3 is reset, and the reading on the digital display spring scale 6-3 is recorded.
After the start of the test:
(13) And opening the hourglass controller, adjusting to a proper flow rate, and synchronously recording the readings displayed by the digital display dial indicator 3-3 and the digital display spring scale 6-3 in real time. When the concrete member traction control box 4 and the internal concrete member generate continuous sliding under the action of horizontal traction force, the test is stopped.
(14) The relation between the horizontal traction force and the time is obtained by recording the reading and the time displayed by the digital display spring balance 6-3, the relation between the horizontal displacement and the time of the concrete member traction control box 4 is obtained by recording the digital display dial indicator 3-3 and the time, so that the relation between the horizontal traction force and the horizontal displacement is obtained, and a relation curve between the shear stress and the shear displacement under the vertical load is obtained by calculation, so that a set of normal stress and ultimate shear stress is obtained.
Normal pressure:
p is a vertical load;
horizontal shear stress:
t is horizontal traction force;
the ultimate shear stress can be obtained from the shear stress and the shear displacement: tau. max
(15) By repeating the steps, the numerical value of the vertical load is changed to obtain multiple groups of normal stress and ultimate shear stress, and then indexes such as cohesive force, internal friction angle and the like of the shearing surface are obtained through calculation.
A first group: sigma 1 ，τ max1
Second group: sigma 2 ，τ max2
Third group: sigma 3 ，τ max3
And a fourth group: sigma 4 ，τ max4
A fifth group: sigma 5 ，τ max5
The shear strength of the interface is described in the form of a straight line by plotting the above 5 groups of points with τ as ordinate and σ as abscissa:
the intercept of the straight line and the vertical coordinate is the cohesive force of the C-interface, and the included angle of the straight line and the horizontal line
The interface internal friction angle.
The above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features thereof, but such modifications or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The utility model provides a visual test device of cast in situ concrete member and soil interface shear behavior which characterized in that includes:
the test platform is used for placing a soil body container groove, a cast-in-place mould, a counterweight balance frame, a horizontal traction device and a traction force generation device;
the soil body container groove is fixed at one end of the test platform and is used for containing a test soil body; a concrete member traction control box is placed in the soil body container groove, a hole for a traction rope to pass through is reserved in the front side of the soil body container groove, and a displacement monitoring device is installed on the rear side of the soil body container groove and used for monitoring the horizontal displacement of the concrete member traction control box;
the concrete member traction control box is sleeved on the concrete member from top to bottom and is used for applying horizontal tension to the concrete member; the concrete member is formed by pouring concrete into the cast-in-place mould;
the counterweight balancing stand is used for providing vertical load for the concrete member and keeping the balance of two sides;
the horizontal traction device is used for applying horizontal tension to the concrete member and the traction control box and adjusting the height through the liftable pulley device;
the traction force generating device is used for providing traction force for the horizontal traction device and controlling the flow of sand in the quicksand pipeline through the flow speed control device;
the cast-in-place mould is used for being inserted into the soil layer of the soil body container groove by 1-3mm and pouring concrete into the cast-in-place mould;
and the digital camera is placed on one side of the test platform and is used for observing the horizontal movement condition of the concrete poured in the soil container groove.
2. The visual testing device for the shear performance of the interface between the cast-in-place concrete member and the soil as claimed in claim 1, wherein the testing platform comprises a testing platform main body and a platform height adjusting device, the platform height adjusting device comprises a supporting sleeve, a lifting rotating ring, a threaded column and a pile bottom cushion block, the upper end of the supporting sleeve is connected with the bottom of the testing platform main body, the lower end of the supporting sleeve is connected with the threaded column through the lifting rotating ring, the upper end of the threaded column is movably arranged in the lower end of the supporting sleeve, and the lower end of the threaded column is connected with the pile bottom cushion block; the lifting rotating ring comprises a rotating handle and a supporting ring, and threads matched with the threaded columns are arranged inside the supporting ring.
3. The visual test device for the shear performance of the cast-in-place concrete member and the soil interface according to claim 1, wherein the soil body container tank is a container tank formed by enclosing three steel plates and toughened glass; the three steel plates are integrated and fixed on the test platform, and a hole for the traction rope to pass through is reserved in the front side of the test platform; the toughened glass is positioned on the side surface and movably connected in the groove tracks of the three steel plates.
4. The visual test device for the shearing performance of the cast-in-place concrete member and the soil interface according to claim 1, wherein the displacement monitoring device comprises a magnetic suction support, a hinge support and a digital display dial indicator, the magnetic suction support is fixed on the test platform, and the digital display dial indicator is connected with the magnetic suction support through the hinge support.
5. The visual test device for the shearing performance of the cast-in-place concrete member and the soil interface as claimed in claim 1, wherein the concrete member traction control box comprises a traction control box body, a balance weight balance frame pin is arranged at the center of the top of the traction control box body, a traction rope hook is arranged on the front side of the traction control box body, and the height of the traction control box body is 2/3 times of the height of the concrete member and is less than 1 time.
6. The visual test device for the shear performance of the cast-in-place concrete member and the soil interface according to claim 1, wherein the counterweight balance frame is composed of 2 counterweight frames, a counterweight block bracket and a plurality of cow-hoof type counterweight blocks, the upper ends of the 2 counterweight frames are connected in a matching way to form an upper end connecting hole for inserting a counterweight balance frame pin at the top of the traction control box, and the lower ends of the 2 counterweight frames are connected in a matching way to form a lower end connecting hole for inserting a threaded rod piece of the counterweight block bracket; the balancing weight support comprises a nut, a threaded rod piece and a bottom support, the threaded rod piece is upwards inserted into the lower end connecting hole and then screwed and fixed through the nut, and the bottom support is used for placing the cow hoof type balancing weight.
7. The visual test device for the shearing performance of the cast-in-place concrete member and the soil interface according to claim 1, wherein the horizontal traction device comprises a traction rope, a pulley, a digital display spring scale and a sand storage container, one end of the traction rope is connected with a traction rope hook of a traction control box of the concrete member, the other end of the traction rope bypasses the pulley and is connected with the upper end of the digital display spring scale, and the traction rope connected with the lower end of the digital display spring scale penetrates through a horizontal traction device hole reserved in the test platform and is connected with the sand storage container.
8. The visual test device for shear performance of a cast-in-place concrete member and a soil interface according to claim 1, wherein the liftable pulley device comprises a pulley pillar diagonal brace, a pulley fixing sleeve, a rotating ring, a liftable threaded pillar and a liftable pulley pillar; the lower end of the lifting pulley pillar is fixed on the test platform, and the upper end of the lifting pulley pillar is connected with the lifting threaded column; two ends of the pulley strut inclined strut are respectively fixed on the test platform and the liftable pulley strut and are used for supporting the liftable pulley strut to keep the liftable pulley strut vertical; the pulley fixing sleeve is connected to the upper end of the lifting threaded column through a rotating ring; an internal thread matched with the lifting threaded column is formed inside the rotating ring, and a rotating handle is arranged outside the rotating ring; the pulley is connected between the two pulley fixing sleeves in a rotating mode.
9. The cast-in-place concrete member and soil interface shear performance visual test device according to claim 1, wherein the traction force generating device comprises an hourglass, a flow rate control device, an hourglass bracket and a quicksand slide; the hourglass is fixed on the test platform through the hourglass support, and the lower end of the hourglass is connected with the quicksand slide through the flow speed control device; the quicksand slide passes through a quicksand slide hole reserved on the test platform and is connected with a sand storage container of the horizontal traction device; the flow velocity control device comprises a quicksand pipeline, a valve support frame, a valve baffle, a support spring, a threaded rod and a rotary handle; the top of the quicksand pipeline is connected with the bottom of the hourglass, the bottom of the quicksand pipeline is connected with the quicksand slideway, and a notch matched with the valve baffle is formed in the middle of the quicksand pipeline; the valve support frame is fixed on one side of the quicksand pipeline and used for supporting the valve baffle; one end of the threaded rod penetrates through a screw hole of the valve support frame to be connected with the rotating handle, and the other end of the threaded rod faces towards the valve blocking piece; the valve blocking piece is partially inserted into the opening of the quicksand pipeline through two supporting springs, and the two supporting springs are connected between the valve blocking piece and the valve supporting frame and are respectively positioned on two sides of the threaded rod; the inserted part of the valve retaining piece is arc-shaped, the diameter of the inserted part is the same as that of the hollow circular ring on the inner wall of the quicksand pipeline, and the inserted part is used for adjusting the falling flow of sand.
10. A visual test method for shear performance of cast-in-place concrete member and soil interface, which is characterized by adopting the device as claimed in any one of claims 1-9 and the following steps:
s1, pouring concrete by adopting a cast-in-place mould, removing the cast-in-place mould after a concrete member is manufactured, and sleeving a concrete member traction control box on the concrete member from top to bottom;
s2, mounting the balance weight balance frame on a traction control box, and placing a Niu Tixing balance weight block according to test requirements;
s3, resetting a digital display dial indicator in the displacement monitoring device, and recording the reading on a digital display spring scale in the horizontal traction device; opening a hourglass controller in the traction force generation device, adjusting to a proper flow rate, and synchronously recording the readings displayed by the digital display dial indicator and the digital display spring scale in real time;
s4, stopping the test when the concrete member traction control box and the internal concrete member generate continuous sliding under the action of horizontal traction force;
s5, recording the reading and the time displayed by the digital display spring scale to obtain the relation between the horizontal traction force and the time, and recording the digital display dial indicator and the time to obtain the relation between the horizontal displacement and the time of the concrete member traction control box so as to obtain the relation between the horizontal traction force and the horizontal displacement; calculating to obtain a relation curve between the shear stress and the shear displacement under the vertical load, so as to obtain a group of normal stress and ultimate shear stress;
and S6, changing the numerical value of the vertical load by repeating the steps S1-S5 to obtain multiple groups of normal stress and ultimate shear stress, and calculating to obtain multiple indexes of the shear surface.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117269042A (en) * | 2023-10-07 | 2023-12-22 | 汇通路桥集团试验检测有限公司 | Pavement material friction performance testing device and method |
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