CN103323340A - Mechanical property test device and method of steel-concrete contact interface - Google Patents

Abstract

The purpose of the invention is to avoid the interference of friction factors and realize the measurement of the mechanical properties of the steel-concrete interface under the conditions of different normal stresses and normal stiffnesses. That is, a test device and method for the mechanical properties of a steel-concrete contact interface. In the present invention, a set of devices can be used to complete at least four tests such as interface equal normal stiffness shear, equal normal stress shear, infinite normal stiffness shear, and interface tension. In addition, in the solution of the present invention, the loading direction of the normal load on the interface is horizontal, perpendicular to the direction of gravity, and parallel to the contact surface between the sample and the base. The application of the normal load will not cause friction that affects the test results, which greatly improves the The precision of the test results. In the solution of the present invention, the area of the contact interface remains unchanged during the interface shearing process, and no experimental error caused by the reduction of the shearing interface will occur.

Description

Device and method for testing mechanical properties of steel-concrete contact interface

technical field

The invention belongs to the field of testing mechanical characteristic parameters of material contact interface, in particular to testing mechanical characteristic of steel-concrete contact interface in civil engineering.

Background technique

With the rapid development of national infrastructure construction, steel casing rock-socketed piles are widely used in major national projects such as long-span bridges, super high-rise buildings, and large wharves. Compared with traditional concrete piles or steel pipe piles, the biggest feature of steel casing rock-socketed piles and similar steel pipe concrete piles is that the outer steel casing and pile core concrete bear the load together, and part of the load acts on the surface of the steel casing , through the interface between the steel casing and the pile core concrete to the inside of the pile and then to the foundation. Therefore, when the pile foundation is loaded, the mechanical properties of the contact interface between steel and concrete will directly affect the performance of the steel casing rock-socketed pile. Bearing performance. The mechanical properties of the interface mainly include the shear properties and tensile properties of the interface. The shear properties include: the change law of shear stress with shear displacement, the law of interface failure, and the change law of residual strength of the interface under repeated shear conditions.

Interface shear test is the basic method to obtain the shear characteristics of steel-concrete interface. The existing interface shear test method and device are generally derived from the method and device of the direct shear test of rock and soil, that is, the steel plate to be tested and the concrete to be tested are respectively placed in the upper and lower shear boxes, and the upper shear box is not fixed. move, and apply a certain vertical load on the top of the upper shear box, and then push the lower shear box at a certain shear rate, so that the contact interface between the two materials produces a shear displacement, and record the shear during this process The relationship between stress and shear displacement; changing different vertical loads to conduct repeated tests to analyze the influence of interface normal stress on interface shear characteristics. Some results have been achieved in similar tests on the shear properties of the steel-concrete interface, but the related test methods and test devices have certain defects. For example, in order to destroy the influence of the interface normal stress on the interface shear properties, the upper shear box Apply a vertical load in the same direction as the gravity, and the load on the material in the upper shear box is transmitted downward through the box wall, and together with the gravity of the upper shear box itself, a certain friction force is generated between the upper and lower shear boxes; At the same time, the lower shear box should be placed on a rigid base, and under the action of the upper load, friction will inevitably be generated between the lower shear box and the base. The shear characteristics of the steel-concrete interface are different from the traditional soil shear test. In order to simulate the actual project, the applied vertical load is generally large. The influence of the above two parts of friction on the test results is generally difficult to ignore, which in turn affects the accuracy of the test results. Spend. For traditional shear tests, the interface contact area will decrease with the increase of shear displacement during the shear process, which will cause errors in the test results. At the same time, for the tensile properties of the steel-concrete contact interface, it is generally necessary to use another test device for testing, resulting in a waste of resources.

The mechanical properties of the steel-concrete contact interface are not only related to the normal stress of the interface, but also related to the normal stiffness of the interface, and are affected by factors such as the strength of the concrete, the roughness of the interface, and the wear resistance of the material. At present, the traditional steel-concrete interface mechanical properties test only studies the shear properties under different normal stress conditions, and has not yet formed a comprehensive and mature steel-concrete interface mechanical properties measurement technology.

Contents of the invention

The purpose of the present invention is to provide a device that avoids the interference of friction factors and can realize the measurement of the mechanical properties of the steel-concrete interface under the conditions of different normal stresses and normal stiffnesses.

The technical solution adopted in order to realize the object of the present invention is as follows. A test device for mechanical properties of a steel-concrete contact interface includes at least two guide rails arranged horizontally and parallel to each other. A base is placed on the guide rail, and fixed rigid baffles and movable rigid baffles are respectively installed at both ends of the guide rail. The board surfaces of the fixed rigid baffle and the movable rigid baffle face the base, the relative positions of the fixed rigid baffle and the guide rail are fixed, and the movable rigid baffle and the base can move along the guide rail under the action of external force. slide.

The base has a horizontal upper end surface. During the test, the upper end face bears the sample to be tested. The sample to be tested includes a steel plate to be tested vertically placed on the base, the two surfaces of the steel plate to be tested face the fixed rigid baffle and the movable rigid baffle respectively, and the two surfaces of the steel plate to be tested are Bond with concrete block I and concrete block II respectively. The side of the concrete block I facing the fixed rigid baffle is in contact with the rigid cover I, and the side of the concrete block II facing the movable rigid baffle is in contact with the rigid cover II. During the test, a connector I was installed between the rigid cover I and the fixed rigid baffle, that is, one end of the connector I was connected to the surface of the rigid cover I, and the other end was connected to the plate of the fixed rigid baffle. noodle. A connector II is installed between the rigid cover II and the movable rigid baffle, that is, one end of the connector II is connected to the surface of the rigid cover II, and the other end is connected to the surface of the movable rigid baffle.

One side of the guide rail has a horizontal loading and measuring device, and the telescopic end of the horizontal loading and measuring device is connected with the steel plate to be tested. During the test, the horizontal loading and measuring device applies a thrust or pull force perpendicular to the direction of the guide rail to the steel plate to be tested.

The plate surface of the movable rigid baffle facing away from the tested sample is connected with the pressure head of the servo hydraulic loading device. During the test, the servo hydraulic loading device applies a thrust parallel to the direction of the guide rail to the movable rigid baffle.

Another object of the present invention is to adopt the above-mentioned steel-concrete contact interface mechanical characteristic testing device to carry out the method for equal normal stiffness test, comprising the following steps:

1) Cut the steel plate for the test into a rectangular steel plate to be tested according to the required size, and the steel plate to be tested has two plate surfaces, two upper and lower end surfaces and two left and right end surfaces. The lower end surface of the steel plate to be tested is rested on the upper surface of the base so that the two surfaces of the steel plate to be tested are perpendicular to the guide rail. The left end surface of the steel plate to be tested is connected with the telescopic end of the horizontal loading device.

2) Setting mold boxes on both sides of the steel plate to be tested and pouring concrete, after curing, the two surfaces of the steel plate to be tested are respectively bonded to concrete block I and concrete block II. The inner side of the concrete block I is bonded to the steel plate to be tested, and the outer side is in contact with the rigid cover plate I. The inner side of the concrete block II is bonded to the steel plate to be tested, and the outer side is in contact with the rigid cover plate II.

3) Install side limiting device I and side limiting device II on the upper surface to limit the movement of concrete block I and concrete block II along the direction perpendicular to the guide rail.

4) Install connecting piece I between the rigid cover plate I and the fixed rigid baffle, and install connecting piece II between the rigid cover II and the movable rigid baffle. The connecting piece I and the connecting piece II are springs.

5) Start the servo-hydraulic loading device to apply a preset load to the movable rigid baffle. After that, the servo hydraulic loading device is locked, so that the position of the movable rigid baffle is fixed.

6) Start the horizontal loading device so that it applies a thrust perpendicular to the direction of the guide rail to the steel plate to be tested. The shear failure occurs at the interface between the steel plate to be tested and the concrete on both sides.

7) Apply a pulling force on the steel plate to be tested in the opposite direction to the thrust described in step 6) through the horizontal loading device, so that the steel plate to be tested returns to the initial position along the moving path in step 6);

8) Apply a thrust in the same direction as the thrust direction described in step 6) to the steel plate to be tested through the horizontal loading device, so that the steel plate to be tested returns to the position at the end of step 6);

9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate to be tested and the concrete tends to be stable, then end the operation.

Another object of the present invention is to use the aforementioned method for testing the mechanical properties of the steel-concrete contact interface to carry out an equal normal pressure test, comprising the following steps:

1) Cut the steel plate for the test into a rectangular steel plate to be tested according to the required size, and the steel plate to be tested has two plate surfaces, two upper and lower end surfaces and two left and right end surfaces. The lower end surface of the steel plate to be tested is rested on the upper surface of the base, and the two plate surfaces of the steel plate to be tested are perpendicular to the guide rail. The left end surface of the steel plate to be tested is connected with the telescopic end of the horizontal loading device.

2) Setting mold boxes on both sides of the steel plate to be tested and pouring concrete, after curing, the two surfaces of the steel plate to be tested are respectively bonded to concrete block I and concrete block II. The inner side of the concrete block I is bonded to the steel plate to be tested, and the outer side is in contact with the rigid cover plate I. The inner side of the concrete block II is bonded to the steel plate to be tested, and the outer side is in contact with the rigid cover plate II.

3) Install side limiting device I and side limiting device II on the upper surface to limit the movement of concrete block I and concrete block II along the direction perpendicular to the guide rail.

4) Install connecting piece I between the rigid cover plate I and the fixed rigid baffle, and install connecting piece II between the rigid cover II and the movable rigid baffle. The connecting piece I and the connecting piece II are springs.

5) Start the servo-hydraulic loading device to apply a preset load to the movable rigid baffle. In the subsequent test process, keep the preset load unchanged.

6) Start the horizontal loading device so that it applies a thrust perpendicular to the direction of the guide rail to the steel plate to be tested. The shear failure occurs at the interface between the steel plate to be tested and the concrete on both sides.

7) Apply a pulling force on the steel plate to be tested in the opposite direction to the thrust described in step 6) through the horizontal loading device, so that the steel plate to be tested returns to the initial position along the moving path in step 6);

8) Apply a thrust in the same direction as the thrust direction described in step 6) to the steel plate to be tested through the horizontal loading device, so that the steel plate to be tested returns to the position at the end of step 6);

9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate to be tested and the concrete tends to be stable, then end the operation.

Another object of the present invention is to adopt the method for testing the mechanical properties of the steel-concrete contact interface described above to carry out the infinite normal stiffness test, which is characterized in that it includes the following steps:

1) Cut the steel plate for the test into a rectangular steel plate to be tested according to the required size, and the steel plate to be tested has two plate surfaces, two upper and lower end surfaces and two left and right end surfaces. The lower end surface of the steel plate to be tested is rested on the upper surface of the base, and the two plate surfaces of the steel plate to be tested are perpendicular to the guide rail. The left end surface of the steel plate to be tested is connected with the telescopic end of the horizontal loading device.

2) Setting mold boxes on both sides of the steel plate to be tested and pouring concrete, after curing, the two surfaces of the steel plate to be tested are respectively bonded to concrete block I and concrete block II. The inner side of the concrete block I is bonded to the steel plate to be tested, and the outer side is in contact with the rigid cover plate I. The inner side of the concrete block II is bonded to the steel plate to be tested, and the outer side is in contact with the rigid cover plate II.

3) Install side limiting device I and side limiting device II on the upper surface to limit the movement of concrete block I and concrete block II along the direction perpendicular to the guide rail.

4) Install connecting piece I between the rigid cover plate I and the fixed rigid baffle, and install connecting piece II between the rigid cover II and the movable rigid baffle. The connecting piece I and the connecting piece II are rigid connecting rods.

5) Start the servo-hydraulic loading device to apply a preset load to the movable rigid baffle. After that, the servo hydraulic loading device is locked, so that the position of the movable rigid baffle is fixed.

6) Start the horizontal loading device so that it applies a thrust perpendicular to the direction of the guide rail to the steel plate to be tested. The shear failure occurs at the interface between the steel plate to be tested and the concrete on both sides.

7) Apply a pulling force on the steel plate to be tested in the opposite direction to the thrust described in step 6) through the horizontal loading device, so that the steel plate to be tested returns to the initial position along the moving path in step 6);

8) Apply a thrust in the same direction as the thrust direction described in step 6) to the steel plate to be tested through the horizontal loading device, so that the steel plate to be tested returns to the position at the end of step 6);

9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate to be tested and the concrete tends to be stable, then end the operation.

Another object of the present invention is to use the steel-concrete contact interface mechanical characteristic testing device described above to carry out the tensile test of the steel-concrete contact interface, comprising the following steps:

1) Cut the test steel plate into a rectangular steel plate to be tested according to the required size. The steel plate to be tested has two plate surfaces, two upper and lower end faces and two left and right end faces; The upper surface of the base, and make the two plate surfaces of the steel plate to be tested perpendicular to the guide rail; the left end surface of the steel plate to be tested is connected with the telescopic end of the horizontal loading device;

2) Set mold boxes on both sides of the steel plate to be tested and pour concrete. After curing, the two surfaces of the steel plate to be tested are respectively bonded to concrete block I and concrete block II; The inner side is bonded to the steel plate to be tested, and the outer side is connected to the rigid cover plate I; the inner side of the concrete block II is bonded to the steel plate to be tested, and the outer side is connected to the rigid cover plate II;

3) Connecting piece I is installed between the rigid cover plate I and the fixed rigid baffle, and connecting piece II is installed between the rigid cover plate II and the movable rigid baffle; the connecting piece I and the connecting piece II are rigid connecting rods ;

4) Start the servo hydraulic loading device to apply tension to the movable rigid baffle until the contact surface between the steel plate to be tested and the concrete block I or concrete block II is destroyed.

Beneficial technical effect of the present invention comprises:

1. A set of equipment can be used to complete at least four tests such as interface equal normal stiffness shear, equal normal stress shear, infinite normal stiffness shear, and interface tension;

2. The loading direction of the normal load on the interface is horizontal, perpendicular to the direction of gravity, and parallel to the contact surface of the sample and the base. The application of the normal load will not cause friction that affects the test results, which greatly improves the accuracy of the test results;

3. The area of the contact interface remains unchanged during the interface shearing process, and there will be no experimental error caused by the reduction of the shearing interface.

Description of drawings

The device of the invention can be further illustrated by the non-limiting examples given in the accompanying drawings.

Fig. 1 is the schematic diagram of embodiment 2 and 3 of the present invention;

Fig. 2 is a schematic diagram of Embodiment 4 of the present invention.

In the figure: 1-horizontal loading and measuring device, 2-lateral limiting device Ⅰ, 3-upper end surface, 4-connecting piece Ⅰ, 5-fixed rigid baffle, 6-rigid cover plate Ⅰ, 7-lateral limiting device Ⅱ, 8-steel plate to be tested, 9-rigid cover Ⅱ, 10-movable rigid baffle, 11-guide rail, 12-servo hydraulic loading device, 13-connector Ⅱ, 15-tested sample, 16-base, 17- Concrete Block I, 18 - Concrete Block II.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but it should not be understood that the scope of the subject matter of the present invention is limited to the following embodiments. Without departing from the above-mentioned technical idea of the present invention, various replacements and changes made according to common technical knowledge and customary means in this field shall be included in the scope of the present invention.

Example 1:

This embodiment discloses a test device for mechanical properties of a steel-concrete contact interface, which includes at least two guide rails 11 arranged horizontally and parallel to each other. A base 16 is placed on the guide rail 11 , and a fixed rigid baffle 5 and a movable rigid baffle 10 are respectively installed at both ends of the guide rail 11 . Since the positional relationship of each component in this embodiment is more important, it is further explained that the "both ends of the guide rail 11" refer to two opposite directions in which objects placed on the guide rail 11 slide along the guide rail.

A plate surface of the fixed rigid baffle 5 faces the base 16. Similarly, a plate surface of the movable rigid baffle 10 also faces the base 16, that is, the base 16 is located between the fixed rigid baffle 5 and the movable rigid baffle 10. . The relative position of the fixed rigid baffle 5 and the guide rail 11 is fixed, and the movable rigid baffle 10 and the base 16 can slide along the guide rail 11 under the action of external force. In the embodiment, the surface of the guide rail 11 has longitudinal grooves or ridges, and the bottoms of the movable rigid baffle 10 and the base 16 have parts that cooperate with the grooves or ridges, so that their lower ends fit into the guide rail 11 and can slide along the guide rail 11.

The base 16 has a horizontal upper face 3 . During the test, the upper end surface 3 bears the sample 15 to be tested. The sample to be tested comprises a steel plate to be tested 8 vertically placed on the base 16, and the two board surfaces of the steel plate to be tested 8 face the fixed rigid baffle 5 and the movable rigid baffle 10 respectively, and the steel plate to be tested The two slab surfaces of 8 are respectively bonded with concrete block I 17 and concrete block II 18. The side of the concrete block I 17 facing the fixed rigid baffle 5 is in contact with the rigid cover I 6, and the side of the concrete block I 17 facing away from the fixed rigid baffle 5 is bonded to the steel plate 8 to be tested. The side of the concrete block II 18 facing the movable rigid baffle 10 is in contact with the rigid cover II 9, and the side of the concrete block II 18 facing away from the movable rigid baffle 10 is bonded to the steel plate 8 to be tested. Both ends of the steel plate 8 to be tested protrude from the concrete block I 17 and the concrete block II 18, that is, the length of the steel plate 8 to be tested perpendicular to the direction of the guide rail is greater than the length of the concrete block II 18 and the concrete block I 17 perpendicular to the direction of the guide rail .

The two ends of all stretch out the end face of concrete block I 17 and concrete block II 18.

Because the heights of the board surfaces of the fixed rigid baffle 5 and the movable rigid baffle 10 are both higher than the height of the upper surface of the base 16 . There is a connecting piece I 4 between the rigid cover plate I 6 and the fixed rigid baffle plate 5. That is, one end of the connector I 4 is connected to the surface of the rigid cover I 6, and the other end is connected to the surface of the fixed rigid baffle 5.

There is a connecting piece II 13 between the rigid cover plate II 9 and the movable rigid baffle plate 10. That is, one end of the connector II 13 is connected to the surface of the rigid cover II 9, and the other end is connected to the surface of the fixed rigid baffle 10.

In the embodiment, the connecting piece I4 and the connecting piece II13 are replaceable parts, which can be both coil springs, or both can be rigid metal rods. Both ends of the coil spring and the metal rod have connecting devices with the board surface, and the coil spring or the metal rod can be replaced as required.

Further, the connecting piece I 4 and the connecting piece II 13 are components that can be converted into rigidity or elasticity. One of the implementation methods is: the connecting piece (that is, the connecting piece I 4 and the connecting piece II 13) includes a cylinder I and a cylinder II sleeved outside the cylinder I, and the cylinder I and the cylinder II can be locked by locking The device is locked, and coil springs are placed inside cylinder body I and cylinder body II. The length of the coil spring is greater than the respective lengths of cylinder body I and cylinder body II, and less than or equal to the sum of the lengths of cylinder body I and cylinder body II. When the cylinder body Ⅰ and cylinder body Ⅱ are locked, the connecting piece (ie connecting piece Ⅰ 4 and connecting piece Ⅱ 13) is a rigid part; when the cylinder body Ⅰ and cylinder body Ⅱ are not locked, the connecting piece ( That is, connecting piece Ⅰ 4 and connecting piece Ⅱ 13) are elastic components.

One side of the guide rail 11 has a horizontal loading and measuring device 1 . When performing certain tests, the telescopic end of the horizontal loading and measuring device 1 is connected to the steel plate 8 to be tested, and the horizontal loading and measuring device 1 applies a thrust or pull force perpendicular to the direction of the guide rail 11 to the steel plate 8 to be tested.

The plate surface of the movable rigid baffle 10 facing away from the tested sample 15 is connected with the pressure head of the servo hydraulic loading device 12 . During the test, the servo hydraulic loading device 12 applies a pushing or pulling force parallel to the direction of the guide rail 11 to the movable rigid baffle 10 .

In this embodiment, the concrete in the tested sample has certain gravity and adhesive force with the upper surface of the base, so it is not easy to slip when pushing and pulling the steel plate to be tested. But as a preference, the concrete can be fixed to the upper surface of the base. One way of realization is: the upper end surface 3 of the base 16 is connected to the side limiting device I 2 and the side limiting device II 7. The side-limiting device I 2 and the side-limiting device II 7 limit the movement of the test sample 15 along the direction perpendicular to the guide rail 11. That is, the bottoms of the confinement device I 2 and the confinement device II 7 are connected to the upper end surface 3 of the base 16, and the two end surfaces of the concrete in the tested sample are in contact with the confinement device I 2 and the confinement device II 7 respectively, so as to limit Movement of concrete blocks.

Example 2:

This embodiment adopts the method for testing the mechanical properties of the steel-concrete contact interface described in Embodiment 1 to perform an equal normal stiffness test, including the following steps:

1) Cut the test steel plate into a rectangular steel plate 15 to be tested according to the required size, and the steel plate to be tested 15 has two plate surfaces, two upper and lower end surfaces and two left and right end surfaces. Place the lower end surface of the steel plate 15 to be tested on the upper surface 3 of the base 16 , and make the two surfaces of the steel plate 15 to be tested perpendicular to the guide rail 11 . The left end surface of the steel plate to be tested is connected to the telescopic end of the horizontal loading device 1 .

2) Set mold boxes on both sides of the steel plate to be tested 15 and pour concrete. After curing, the two surfaces of the steel plate to be tested are bonded to the concrete block I 17 and the concrete block II 18 respectively. The inner side of the concrete block I 17 is bonded to the steel plate 15 to be tested, and the outer side is in contact with the rigid cover plate I 6, but not connected. The inner side of the concrete block II 18 is bonded to the steel plate 15 to be tested, and the outer side is in contact with the rigid cover plate II 9, but not connected.

3) On the upper surface 3, install the side-limiting device I 2 and the side-limiting device II 7 that restrict the movement of the concrete block I and the concrete block II along the direction perpendicular to the guide rail 11.

4) Install connecting piece Ⅰ 4 between the rigid cover Ⅰ 6 and the fixed rigid baffle 5, and install connecting piece Ⅱ 13 between the rigid cover Ⅱ 9 and the movable rigid baffle 10. The connector I 4 and the connector II 13 are elastic components, and this embodiment is a coil spring.

5) Start the servo hydraulic loading device 12 to apply a preset load to the movable rigid baffle 10 . After that, the servo hydraulic loading device is locked, so that the position of the movable rigid baffle 10 is fixed. Turn on the pressure sensor on the servo hydraulic loading device to measure the change of normal pressure during the test.

6) Start the horizontal loading device 1 so that it applies a thrust perpendicular to the direction of the guide rail 11 to the steel plate 8 to be tested. This causes shear failure to occur at the interface between the steel plate 8 to be tested and the concrete on both sides. The interfacial shear test was performed at a constant shear rate and the change in horizontal thrust was measured during the increase in shear displacement.

7) Apply a pulling force on the steel plate 8 to be tested through the horizontal loading device 1 in the opposite direction to the thrust described in step 6), so that the steel plate to be tested returns to the initial position along the moving path in step 6), and measure the normal pressure in the process change and the change in horizontal thrust during the increase in shear displacement.

8) Apply a thrust in the same direction as that in step 6) to the steel plate 8 to be tested through the horizontal loading device 1, so that the steel plate to be tested returns to the position at the end of step 6), and measure the change of normal pressure and Variation of horizontal thrust during increasing shear displacement.

9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate 8 to be tested and the concrete tends to be stable, that is, when the pushing force applied in step 7) is equal to the pulling force applied in step 8), the operation ends.

In this example, the quantities to be measured include: the load described in step 5), the displacement of the steel plate when the thrust and shear failure occurred in step 6), the tensile force described in step 7), and repeating steps 7) to 8) The magnitude of the pulling or pushing force until the shear strength of the contact interface between the steel plate 8 to be tested and the concrete becomes stable. Repeat the test by changing the normal stiffness and initial normal stress, through the relationship between the interface shear displacement and shear stress measured in the test, the relationship between the normal displacement and shear displacement of the concrete to be measured, and the interface normal stress The relationship between the shear displacement and the residual shear strength under the repeated shearing action of the interface is used to analyze the shear law of the interface.

Example 3:

A method for performing an isonormal pressure test using the steel-concrete contact interface mechanical property testing device described in claim 1 or 2, characterized in that it comprises the following steps:

1) Cut the test steel plate into a rectangular steel plate 15 to be tested according to the required size, and the steel plate to be tested 15 has two plate surfaces, two upper and lower end surfaces and two left and right end surfaces. Place the lower end surface of the steel plate 15 to be tested on the upper surface 3 of the base 16 , and make the two surfaces of the steel plate 15 to be tested perpendicular to the guide rail 11 . The left end surface of the steel plate to be tested is connected to the telescopic end of the horizontal loading device 1 .

2) Set mold boxes on both sides of the steel plate to be tested 15 and pour concrete. After curing, the two surfaces of the steel plate to be tested are bonded to the concrete block I 17 and the concrete block II 18 respectively. The inner side of the concrete block I 17 is bonded to the steel plate 15 to be tested, and the outer side is in contact with the rigid cover plate I 6, but not connected. The inner side of the concrete block II 18 is bonded to the steel plate 15 to be tested, and the outer side is in contact with the rigid cover plate II 9, but not connected.

3) On the upper surface 3, install the side-limiting device I 2 and the side-limiting device II 7 that restrict the movement of the concrete block I and the concrete block II along the direction perpendicular to the guide rail 11.

4) Install connecting piece Ⅰ 4 between the rigid cover Ⅰ 6 and the fixed rigid baffle 5, and install connecting piece Ⅱ 13 between the rigid cover Ⅱ 9 and the movable rigid baffle 10. The connector I 4 and the connector II 13 are elastic components, and this embodiment is a coil spring.

5) Start the servo hydraulic loading device 12 to apply a preset load to the movable rigid baffle 10 . In the subsequent test process, keep the preset load unchanged. Turn on the displacement sensor on the servo hydraulic loading device to measure the change in the normal displacement of the top surface of the concrete to be tested during the test.

6) Start the horizontal loading device 1 so that it applies a thrust perpendicular to the direction of the guide rail 11 to the steel plate 8 to be tested. This causes shear failure to occur at the interface between the steel plate 8 to be tested and the concrete on both sides. The interfacial shear test was performed at a constant shear rate and the change in horizontal thrust was measured during the increase in shear displacement.

7) Apply a pulling force on the steel plate 8 to be tested through the horizontal loading device 1 in the opposite direction to the thrust described in step 6), so that the steel plate to be tested returns to the initial position along the moving path in step 6), and measure the normal pressure in the process change and the change in horizontal thrust during the increase in shear displacement.

8) Apply a thrust in the same direction as the thrust direction described in step 6) to the steel plate to be tested through the horizontal loading device 1, so that the steel plate to be tested returns to the position at the end of step 6); and measure the change of normal displacement and Variation of horizontal thrust during increasing shear displacement.

9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate 8 to be tested and the concrete tends to be stable, that is, when the pushing force applied in step 7) is equal to the pulling force applied in step 8), the operation ends.

In this example, the quantities to be measured include: the load described in step 5), the displacement of the steel plate when the thrust and shear failure occurred in step 6), the tensile force described in step 7), and repeating steps 7) to 8) The magnitude of the pulling or pushing force until the shear strength of the contact interface between the steel plate 8 to be tested and the concrete becomes stable. Repeat the test by changing the normal stress, and analyze the shear law of the interface according to the relationship between the interface shear displacement and shear stress measured in the test and the residual shear strength under the repeated shearing action of the interface.

Example 4:

A method for performing an infinite normal stiffness test using the test device for the mechanical properties of the steel-concrete contact interface described in claim 1 or 2, characterized in that it comprises the following steps:

1) Cut the test steel plate into a rectangular steel plate 15 to be tested according to the required size, and the steel plate to be tested 15 has two plate surfaces, two upper and lower end surfaces and two left and right end surfaces. Place the lower end surface of the steel plate 15 to be tested on the upper surface 3 of the base 16 , and make the two surfaces of the steel plate 15 to be tested perpendicular to the guide rail 11 . The left end surface of the steel plate to be tested is connected to the telescopic end of the horizontal loading device 1 .

2) Set mold boxes on both sides of the steel plate to be tested 15 and pour concrete. After curing, the two surfaces of the steel plate to be tested are bonded to the concrete block I 17 and the concrete block II 18 respectively. The inner side of the concrete block I 17 is bonded to the steel plate 15 to be tested, and the outer side is in contact with the rigid cover plate I 6, but not connected. The inner side of the concrete block II 18 is bonded to the steel plate 15 to be tested, and the outer side is in contact with the rigid cover plate II 9, but not connected.

3) On the upper surface 3, install the side-limiting device I 2 and the side-limiting device II 7 that restrict the movement of the concrete block I and the concrete block II along the direction perpendicular to the guide rail 11.

4) Install connecting piece Ⅰ 4 between the rigid cover Ⅰ 6 and the fixed rigid baffle 5, and install connecting piece Ⅱ 13 between the rigid cover Ⅱ 9 and the movable rigid baffle 10. The connecting piece I 4 and the connecting piece II 13 are rigid components, and this embodiment is a rigid metal connecting rod.

5) Start the servo hydraulic loading device 12 to apply a preset load to the movable rigid baffle 10 . After that, the servo hydraulic loading device is locked, so that the position of the movable rigid baffle 10 is fixed. Turn on the pressure sensor on the servo hydraulic loading device to measure the change of normal pressure during the test.

6) Start the horizontal loading device 1 so that it applies a thrust perpendicular to the direction of the guide rail 11 to the steel plate 8 to be tested. This causes shear failure to occur at the interface between the steel plate 8 to be tested and the concrete on both sides. The interfacial shear test was performed at a constant shear rate and the change in horizontal thrust was measured during the increase in shear displacement.

7) Apply a pulling force on the steel plate 8 to be tested through the horizontal loading device 1 in the opposite direction to the thrust described in step 6), so that the steel plate to be tested returns to the initial position along the moving path of step 6); carry out interface shearing at a constant shear rate Test, and measure the change in horizontal thrust as the shear displacement increases.

8) Apply a thrust in the same direction as that in step 6) to the steel plate 8 to be tested through the horizontal loading device 1, so that the steel plate to be tested returns to the position at the end of step 6); and measure the change of normal pressure and Variation of horizontal thrust during increasing shear displacement.

9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate 8 to be tested and the concrete tends to be stable, that is, when the pushing force applied in step 7) is equal to the pulling force applied in step 8), the operation ends.

In this example, the quantities to be measured include: the load described in step 5), the displacement of the steel plate when the thrust and shear failure occurred in step 6), the tensile force described in step 7), and repeating steps 7) to 8) The magnitude of the pulling or pushing force until the shear strength of the contact interface between the steel plate 8 to be tested and the concrete becomes stable. Repeat the test by changing the initial normal stress, through the relationship between the interface shear displacement and shear stress measured in the test, the relationship between the interface normal stress and shear displacement, and the residual shear under repeated interface shear Strength, analyze the shear law of the interface.

Example 5:

A method for performing an interface tensile test using the steel-concrete contact interface mechanical property testing device described in claim 1 or 2, comprising the following steps:

1) Cut the test steel plate into a rectangular steel plate 15 to be tested according to the required size, and the steel plate to be tested 15 has two plate surfaces, two upper and lower end surfaces and two left and right end surfaces. Place the lower end surface of the steel plate 15 to be tested on the upper surface 3 of the base 16 , and make the two surfaces of the steel plate 15 to be tested perpendicular to the guide rail 11 .

2) Set mold boxes on both sides of the steel plate to be tested 15 and pour concrete. After curing, the two surfaces of the steel plate to be tested are respectively bonded to the concrete block I17 and the concrete block II18. The inner side of the concrete block I17 is bonded to the steel plate 15 to be tested, and the outer side is connected to the rigid cover plate I6; the inner side of the concrete block II18 is bonded to the steel plate 15 to be tested, and the outer side is connected to the rigid cover plate II9. That is, both the rigid cover plate I6 and the rigid cover plate II9 are anchored to the concrete block.

3) Install the connector I4 between the rigid cover I6 and the fixed rigid baffle 5, and install the connector II13 between the rigid cover II9 and the movable rigid baffle 10. The connecting piece I4 and the connecting piece II13 are rigid connecting rods. That is, when the movable rigid baffle 10 is dragged, the rigid cover II 9 can be dragged.

4) Start the servo hydraulic loading device 12 to apply tension to the movable rigid baffle 10 . until the contact surface between the steel plate 15 to be tested and the concrete block I17 or concrete block II18 is broken; that is, the concrete block I17 or concrete block II18 is separated from the steel plate 15 to be tested.

In this embodiment, through the above steps, the tensile force exerted by the servo hydraulic loading device on the rigid cover plate II9 can be gradually increased and measured, and the ultimate tensile stress when the steel-concrete contact interface is damaged by tension can be determined.

Change the strength of concrete and the surface roughness of the steel plate to recreate the tested sample. Repeat the above steps to conduct tests to determine the relationship between the tensile properties of the steel-concrete interface, the strength of the concrete, and the roughness of the interface.

Claims (6)

1. A test device for mechanical properties of a steel-concrete contact interface, characterized in that: it comprises at least two guide rails (11) arranged horizontally and parallel to each other; a base (16) is placed on the guide rails (11), and the guide rails The two ends of (11) are respectively installed with a fixed rigid baffle (5) and a movable rigid baffle (10); one surface of the fixed rigid baffle (5) and the movable rigid baffle (10) faces the base (16), the relative position of the fixed rigid baffle (5) and the guide rail (11) is fixed, and the movable rigid baffle (10) and the base (16) can move along the guide rail (11) under the action of external force slide; The base (16) has a horizontal upper end surface (3); during the test, the upper end surface (3) bears the tested sample (15); the tested sample (15) includes the steel plate (8) to be tested, concrete block I (17) and concrete block II (18), the steel plate to be tested (8) is placed vertically on the upper end surface (3) of the base (16), and the two surfaces of the steel plate to be tested (8) face respectively A fixed rigid baffle (5) and a movable rigid baffle (10), the two surfaces of the steel plate to be tested (8) are respectively bonded to concrete block I (17) and concrete block II (18); the concrete The side of the block I (17) facing the fixed rigid baffle (5) is in contact with the rigid cover I (6), and the side of the concrete block II (18) facing the movable rigid baffle (10) is in contact with the rigid cover II ( 9) Contact; during the test, a connector I (4) is installed between the rigid cover I (6) and the fixed rigid baffle (5), and the rigid cover II (9) and the movable rigid baffle (10) is installed with connector II (13); One side of the guide rail (11) has a horizontal loading and measuring device (1); during the test, the telescopic end of the horizontal loading and measuring device (1) is connected to the steel plate (8) to be tested, and the horizontal loading And the measuring device (1) applies a thrust or pull force perpendicular to the direction of the guide rail (11) to the steel plate (8) to be tested; The movable rigid baffle (10) is connected to the pressure head of the servo hydraulic loading device (12) with its back facing the tested sample (15); during the test, the servo hydraulic loading device (12) The baffle (10) exerts a thrust parallel to the direction of the guide rail (11). 2. The test device for the mechanical properties of the steel-concrete contact interface according to claim 1, characterized in that: the upper end surface (3) of the base (16) is connected to the confinement device I (2) and the confinement device II (7 ); the side-limiting device I (2) and the side-limiting device II (7) limit the movement of the tested sample (15) along a direction perpendicular to the guide rail (11). 3. A method that adopts the described steel-concrete contact interface mechanical characteristic testing device of claim 1 or 2 to carry out the method of equal normal stiffness test, is characterized in that, comprises the following steps: 1) Cut the test steel plate into a rectangular steel plate to be tested (15) according to the required size, the steel plate to be tested (15) has two plate surfaces, two upper and lower end faces and two left and right end faces; the steel plate to be tested The lower end surface of (15) rests on the upper surface (3) of the base (16), and makes the two plate surfaces of the steel plate to be tested (15) perpendicular to the guide rail (11); the left end of the steel plate to be tested The surface is connected with the telescopic end of the horizontal loading device (1); 2) Set mold boxes on both sides of the steel plate to be tested (15) and pour concrete. After curing, the two surfaces of the steel plate to be tested are respectively connected to the concrete block I (17) and the concrete block II (18 ) bonding; the inner side of the concrete block I (17) is bonded to the steel plate (15) to be tested, and the outer side is in contact with the rigid cover plate I (6); the inner side of the concrete block II (18) is in contact with the steel plate (15) to be tested Adhesive, the outer side is in contact with the rigid cover II (9); 3) Install side-limiting device I (2) and side-limiting device II (7) on the upper surface (3) to limit the movement of concrete block I and concrete block II along the direction perpendicular to the guide rail (11); 4) Install the connector I (4) between the rigid cover I (6) and the fixed rigid baffle (5), and install the connector between the rigid cover II (9) and the movable rigid baffle (10) II (13); said connector I (4) and connector II (13) are springs; 5) Start the servo hydraulic loading device (12) to apply a preset load to the movable rigid baffle (10); after that, lock the servo hydraulic loading device so that the position of the movable rigid baffle (10) is fixed ; 6) Start the horizontal loading device (1), so that it applies a thrust perpendicular to the direction of the guide rail (11) to the steel plate (8) to be tested; so that shear failure occurs at the interface between the steel plate (8) to be tested and the concrete on both sides; 7) Using the horizontal loading device (1) to apply a pulling force opposite to the thrust direction described in step 6) to the steel plate to be tested (8), so that the steel plate to be tested returns to the initial position along the moving path in step 6); 8) Apply a thrust in the same direction as the thrust described in step 6) through the horizontal loading device (1) to the steel plate to be tested (8), so that the steel plate to be tested returns to the position at the end of step 6); 9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate (8) to be tested and the concrete tends to be stable, and then end the operation. 4. A method for carrying out an equal normal pressure test using the steel-concrete contact interface mechanical property testing device described in claim 1 or 2, is characterized in that, comprises the following steps: 1) Cut the test steel plate into a rectangular steel plate to be tested (15) according to the required size, the steel plate to be tested (15) has two plate surfaces, two upper and lower end faces and two left and right end faces; the steel plate to be tested The lower end surface of (15) rests on the upper surface (3) of the base (16), and makes the two plate surfaces of the steel plate to be tested (15) perpendicular to the guide rail (11); the left end of the steel plate to be tested The surface is connected with the telescopic end of the horizontal loading device (1); 2) Set mold boxes on both sides of the steel plate to be tested (15) and pour concrete. After curing, the two surfaces of the steel plate to be tested are respectively connected to the concrete block I (17) and the concrete block II (18 ) bonding; the inner side of the concrete block I (17) is bonded to the steel plate (15) to be tested, and the outer side is in contact with the rigid cover plate I (6); the inner side of the concrete block II (18) is in contact with the steel plate (15) to be tested Adhesive, the outer side is in contact with the rigid cover II (9); 3) Install side-limiting device I (2) and side-limiting device II (7) on the upper surface (3) to limit the movement of concrete block I and concrete block II along the direction perpendicular to the guide rail (11); 4) Install the connector I (4) between the rigid cover I (6) and the fixed rigid baffle (5), and install the connector between the rigid cover II (9) and the movable rigid baffle (10) II (13); said connector I (4) and connector II (13) are springs; 5) Start the servo-hydraulic loading device (12) to apply a preset load to the movable rigid baffle (10); keep the preset load unchanged during the subsequent test; 6) Start the horizontal loading device (1), so that it applies a thrust perpendicular to the direction of the guide rail (11) to the steel plate (8) to be tested; so that shear failure occurs at the interface between the steel plate (8) to be tested and the concrete on both sides; 7) Using the horizontal loading device (1) to apply a pulling force opposite to the thrust direction described in step 6) to the steel plate to be tested (8), so that the steel plate to be tested returns to the initial position along the moving path in step 6); 8) Apply a thrust in the same direction as the thrust described in step 6) through the horizontal loading device (1) to the steel plate to be tested (8), so that the steel plate to be tested returns to the position at the end of step 6); 9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate (8) to be tested and the concrete tends to be stable, and then end the operation. 5. A method for carrying out the infinite normal stiffness test using the steel-concrete contact interface mechanical characteristic testing device described in claim 1 or 2, it is characterized in that, comprising the following steps: 1) Cut the test steel plate into a rectangular steel plate to be tested (15) according to the required size, the steel plate to be tested (15) has two plate surfaces, two upper and lower end faces and two left and right end faces; the steel plate to be tested The lower end surface of (15) rests on the upper surface (3) of the base (16), and makes the two plate surfaces of the steel plate to be tested (15) perpendicular to the guide rail (11); the left end of the steel plate to be tested The surface is connected with the telescopic end of the horizontal loading device (1); 2) Set mold boxes on both sides of the steel plate to be tested (15) and pour concrete. After curing, the two surfaces of the steel plate to be tested are respectively connected to the concrete block I (17) and the concrete block II (18 ) bonding; the inner side of the concrete block I (17) is bonded to the steel plate (15) to be tested, and the outer side is in contact with the rigid cover plate I (6); the inner side of the concrete block II (18) is in contact with the steel plate (15) to be tested Adhesive, the outer side is in contact with the rigid cover II (9); 3) Install side-limiting device I (2) and side-limiting device II (7) on the upper surface (3) to limit the movement of concrete block I and concrete block II along the direction perpendicular to the guide rail (11); 4) Install the connector I (4) between the rigid cover I (6) and the fixed rigid baffle (5), and install the connector between the rigid cover II (9) and the movable rigid baffle (10) II (13); said connector I (4) and connector II (13) are rigid connecting rods; 5) Start the servo hydraulic loading device (12) to apply a preset load to the movable rigid baffle (10); after that, lock the servo hydraulic loading device so that the position of the movable rigid baffle (10) is fixed ; 6) Start the horizontal loading device (1), so that it applies a thrust perpendicular to the direction of the guide rail (11) to the steel plate (8) to be tested; so that shear failure occurs at the interface between the steel plate (8) to be tested and the concrete on both sides; 7) Using the horizontal loading device (1) to apply a pulling force opposite to the thrust direction described in step 6) to the steel plate to be tested (8), so that the steel plate to be tested returns to the initial position along the moving path in step 6); 8) Apply a thrust in the same direction as the thrust described in step 6) through the horizontal loading device (1) to the steel plate to be tested (8), so that the steel plate to be tested returns to the position at the end of step 6); 9) Repeat steps 7) to 8) until the shear strength of the contact interface between the steel plate (8) to be tested and the concrete tends to be stable, and then end the operation. 6. A method for carrying out the interface tensile test using the steel-concrete contact interface mechanical property testing device described in claim 1 or 2, it is characterized in that, comprising the following steps: 1) Cut the test steel plate into a rectangular steel plate to be tested (15) according to the required size, the steel plate to be tested (15) has two plate surfaces, two upper and lower end faces and two left and right end faces; the steel plate to be tested The lower end surface of (15) rests on the upper surface (3) of the base (16), and makes the two plate surfaces of the steel plate to be tested (15) perpendicular to the guide rail (11); the left end of the steel plate to be tested The surface is connected with the telescopic end of the horizontal loading device (1); 2) Set mold boxes on both sides of the steel plate to be tested (15) and pour concrete. After curing, the two surfaces of the steel plate to be tested are respectively connected to the concrete block I (17) and the concrete block II (18 ) bonding; the inner side of the concrete block I (17) is bonded to the steel plate (15) to be tested, and the outer side is connected to the rigid cover plate I (6); the inner side of the concrete block II (18) is connected to the steel plate (15) to be tested Bonding, the outer side is connected with the rigid cover plate II (9); 3) Install the connector I (4) between the rigid cover I (6) and the fixed rigid baffle (5), and install the connector between the rigid cover II (9) and the movable rigid baffle (10) II (13); said connector I (4) and connector II (13) are rigid connecting rods; 4) Start the servo hydraulic loading device (12) to apply tension to the movable rigid baffle (10); until the contact surface between the steel plate (15) to be tested and the concrete block I (17) or concrete block II (18) is destroyed .

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