Experimental device for simulating uplift pressure loading of concrete canal lining

Abstract

The invention provides an experimental device for loading uplift pressure of a concrete canal lining, and relates to the technical field of concrete precast block testing. The concrete channel lining uplift pressure loading experimental device comprises a platform frame baffle, vertical supporting legs are arranged at the four opposite angles of the lower end face of the platform frame baffle, a supporting rod frame is arranged at the lower position in the platform frame baffle, and a square hole is formed in the center of the upper end face of the supporting rod frame. An experiment structure is arranged on the upper end face of the supporting rod frame located at the upper end of the square hole, the experiment structure comprises seven channel concrete precast blocks, and cement mortar is arranged among the seven channel concrete precast blocks. Through vertical loading of the channel concrete precast blocks, the corresponding relation between the load borne by the channel concrete precast blocks under the effect of uplift pressure load and the uplift displacement of the central channel concrete precast blocks and the uplift displacement of the edge channel concrete precast blocks can be monitored in real time, and the ultimate bearing capacity of the lining structure in the process that uplift pressure is gradually increased is observed.

Description

Technical Field

[0001] The invention relates to the technical field of concrete prefabricated block testing, in particular to an experimental device for simulating uplift pressure loading of concrete channel lining. Background Art

[0002] In order to reduce channel water leakage, save water, improve canal water utilization, ensure water safety, and give full play to the benefits of water diversion projects, it is very necessary to line the water diversion channel. During the channel lining construction, we often encounter projects with small construction space, short construction period and high construction quality requirements. Ordinary cast-in-place concrete structures are difficult to meet the construction requirements, so the construction of assembled concrete precast blocks came into being. The concrete precast block lining has the following advantages: the use of concrete precast blocks transfers most of the on-site construction work to the prefabrication factory, replaces manual construction with mechanized construction, and then transports them to the site for installation and construction. The on-site installation and construction is flexible, and manual or small machinery can be used to assist construction, reducing temporary projects such as on-site formwork, which is conducive to speeding up the construction progress, improving construction quality, and reducing construction risks. Concrete precast blocks are a detachable and reusable lining form that meets the requirements of the circular economy. The cast-in-place concrete surface layer is prone to cracks and breaks under the influence of large loads and temperature, while concrete precast blocks have strong adaptability to bearing capacity and temperature stress.

[0003] Anti-floating performance is one of the important indicators in the design of channel concrete precast block lining. The biggest difference between the anti-floating performance of concrete precast blocks and that of cast-in-place concrete lies in the existence of construction joints. The plates are adhered to each other through the cement mortar at the joint interface, resulting in poor integrity. Under the load caused by groundwater at the bottom of the channel, the cement mortar at the joint interface is prone to cracking. Therefore, the performance of the joint material, especially its bonding ability with the concrete precast blocks, has a great influence on the anti-floating stability of the channel lining. If the anti-floating data indicators of the concrete precast blocks cannot be accurately grasped, the concrete precast blocks are prone to bulge when encountering the uplift pressure at the bottom of the channel during application, resulting in large-scale damage, thereby affecting the safety of channel water supply.

[0004] At present, the anti-floating performance test of concrete precast blocks under load uses a relatively primitive method. Static loading devices such as hydraulic loading devices basically load vertically on the upper part or side of the component, and there is no lower supporting structure. It is unable to accurately reflect the stress state of the joints of the lining plate, a component with a large deadweight. It has certain limitations in terms of operational convenience, test efficiency, loading accuracy and reliability, and the corresponding relationship between stress, strain and displacement of various parts of the block under loading. It is impossible to obtain accurate test data. Therefore, those skilled in the art provide an experimental device for uplift pressure loading of concrete channel lining to solve the problems raised in the above background technology. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the shortcomings of the prior art, the present invention provides an experimental device for uplift pressure loading of concrete channel lining, which solves the problem that static loading devices such as hydraulic loading devices basically load vertically on the upper part or side of the component and have no lower supporting structure, and cannot accurately reflect the stress state of the joints of the lining plate, a component with a large dead weight. It has certain limitations in terms of operational convenience, test efficiency and loading accuracy and reliability, and the corresponding relationship between stress, strain and displacement of various parts of the block under loading, and cannot obtain accurate test data.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: an experimental device for uplift pressure loading of concrete channel lining, comprising a platform frame baffle, wherein four diagonal portions of the lower end surface of the platform frame baffle are provided with vertical support legs, a support rod frame is provided at the lower part of the inside of the platform frame baffle, a square hole is provided at the center of the upper end surface of the support rod frame, and an experimental structure is provided on the upper end surface of the support rod frame at the upper end of the square hole, the experimental structure comprises seven channel concrete prefabricated blocks, cement mortar is provided between the seven channel concrete prefabricated blocks, limit rod reserved holes are provided at the center of the two inner side walls of the platform frame baffle, at the center of the front and rear inner side walls of the platform frame baffle, and at the two sides of the center of the front and rear inner side walls of the platform frame baffle, limit structures are provided at both sides of the upper end surface of the support rod frame, a jacking structure is provided at the lower end of the square hole, and a micrometer fixing bracket is provided at one side of the center of the upper end surface of the platform frame baffle.

[0009] Preferably, the limiting structure includes a limiting rod body and a bow-shaped limiting rod, the limiting rod body passes through a limiting rod reserved hole on one side to the outside of the platform frame baffle, and the bow-shaped limiting rod is arranged at the end of the limiting rod body inside the platform frame baffle, and the end is attached to a side wall of the experimental structure.

[0010] Preferably, the lifting structure includes a base plate, a lifting control, a machine body, a claw block, a tension spring, an anti-slip gasket, a first pressure sensor and an automatic leveling gasket. The lifting control is arranged at the front center of the upper end surface of the base plate, the machine body is arranged at the center of the upper end surface of the base plate, the claw block is arranged on the output end of the machine body, the tension spring is arranged at the upper center of one side wall of the claw block, the other end of the tension spring is fixedly connected to the upper end surface of the base plate, the anti-slip gasket is arranged on the upper end surface of the claw block, the first pressure sensor is arranged on the upper end surface of the anti-slip gasket, and the automatic leveling gasket is arranged on the upper end surface of the first pressure sensor.

[0011] Preferably, the top of the automatic leveling gasket is hemispherical.

[0012] Preferably, the six channel concrete precast blocks are respectively arranged around the central channel concrete precast block, and a 2 cm spacing is reserved between the central channel concrete precast block. The experimental cement mortar is laid in the joints between the central channel concrete precast block and the six channel concrete precast blocks at the edge. The model of the channel concrete precast block is C30, and the model of the cement mortar is M15.

[0013] Preferably, a force-displacement measuring device is provided at one end of the micrometer fixing bracket, and the force-displacement measuring device includes a micrometer, a magnetic base, a fixed rod bracket, a reading microscope, a steel ruler, a pressure sensor and a sensor reader. The pressure sensor is connected to the sensor reader, and the sensor reader records the pressure exerted on the pressure sensor in real time. In addition, a reading microscope and a steel ruler are provided to assist in the measurement.

[0014] Preferably, the micrometer fixing bracket is L-shaped, with the shorter side of the bracket fixed to the platform frame baffle and the longer side horizontally located at the upper end of the square hole. The micrometer fixing bracket can rotate with the short side as the axis. Two micrometers are fixed on the micrometer fixing bracket, and the probes of the two micrometers are respectively arranged at the symmetrical center positions of the channel concrete precast block at the center and the six channel concrete precast blocks at the edge, and the two micrometers respectively record the vertical displacement of the lining plate.

[0015] (III) Beneficial effects

[0016] The present invention provides an experimental device for uplift pressure loading of concrete channel lining. It has the following beneficial effects:

[0017] 1. In the present invention, by vertically loading the channel concrete precast blocks, the corresponding relationship between the load on the channel concrete precast blocks under the vertical load and the rising displacement of the channel concrete precast blocks at the center and the edge channel concrete precast blocks can be monitored in real time. The device is easy to disassemble, the experimental process is simple, and the test efficiency is high. The test process is labor-saving, highly controllable, and safer through loading through the jacking structure. Through detection by multiple devices, the experimental results are obvious and the data is accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A perspective view of the present invention;

[0019] Figure 2 A top view of the present invention;

[0020] Figure 3 A three-dimensional diagram of a platform frame baffle of the present invention;

[0021] Figure 4 It is a three-dimensional diagram of the jacking structure of the present invention;

[0022] Figure 5A three-dimensional diagram of another viewing angle of the present invention;

[0023] Figure 6 for Figure 1 A magnified schematic diagram of center A.

[0024] Among them, 1. Platform frame baffle; 2. Micrometer fixing bracket; 3. Experimental structure; 301. Channel concrete precast block; 302. Cement mortar; 4. Limiting structure; 401. Limiting rod body; 402. Bow-shaped limiting rod; 5. Support rod frame; 6. Vertical supporting leg; 7. Square hole; 8. Limiting rod reserved hole; 9. Lifting structure; 901. Bottom plate; 902. Lifting control; 903. Machine body; 904. Claw block; 905. Tension spring; 906. Anti-slip gasket; 907. First pressure sensor; 908. Automatic leveling gasket. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] like Figure 1-6 As shown, an embodiment of the present invention provides an experimental device for uplift pressure loading of concrete channel lining, including a platform frame baffle 1, wherein four diagonal portions of the lower end surface of the platform frame baffle 1 are provided with vertical support legs 6, a support rod frame 5 is provided at the lower part of the inside of the platform frame baffle 1, a square hole 7 is provided at the center of the upper end surface of the support rod frame 5, and an experimental structure 3 is provided on the upper end surface of the support rod frame 5 at the upper end of the square hole 7, wherein the experimental structure 3 includes seven channel concrete prefabricated blocks 301, cement mortar 302 is provided between the seven channel concrete prefabricated blocks 301, and a vertical support leg 6 is provided at the center of the two inner side walls and the flat surface of the platform frame baffle 1. Limit rod reserved holes 8 are provided at the center of the front and rear inner walls of the platform frame baffle 1 and at the two sides of the center of the front and rear inner walls of the platform frame baffle 1, limit structures 4 are provided on both sides of the upper end surface of the support rod frame 5, and a jacking structure 9 is provided at the lower end of the square hole 7. By jacking through the jacking structure 9, the corresponding relationship between the load on the channel concrete precast block 301 under the action of the vertical load and the rising displacement of the channel concrete precast block 301 at the center and the edge channel concrete precast block 301 can be monitored in real time, and a micrometer fixing bracket 2 is provided at one side of the center of the upper end surface of the platform frame baffle 1.

[0028] The limiting structure 4 includes a limiting rod body 401 and a bow-shaped limiting rod 402. The limiting rod body 401 passes through the limiting rod reserved hole 8 on one side and reaches the outside of the platform frame baffle 1. The bow-shaped limiting rod 402 is arranged at the end of the limiting rod body 401 inside the platform frame baffle 1, and the end is attached to a side wall of the experimental structure 3. The experimental structure 3 is clamped by attaching the bow-shaped limiting rod 402 to the experimental structure 3.

[0029] The lifting structure 9 includes a bottom plate 901, a lifting control 902, a body 903, a claw block 904, a tension spring 905, an anti-slip pad 906, a first pressure sensor 907 and an automatic leveling pad 908. The lifting control 902 is arranged at the front center of the upper end surface of the bottom plate 901, the body 903 is arranged at the center of the upper end surface of the bottom plate 901, the claw block 904 is arranged on the output end of the body 903, the tension spring 905 is arranged at the upper center of one side wall of the claw block 904, and the other end of the tension spring 905 is fixedly connected to the On the upper end surface of the bottom plate 901, an anti-skid pad 906 is arranged on the upper end surface of the claw block 904, a first pressure sensor 907 is arranged on the upper end surface of the anti-skid pad 906, and an automatic leveling pad 908 is arranged on the upper end surface of the first pressure sensor 907. By lifting through the jacking structure 9, the load on the channel concrete precast block 301 under the action of the vertical load and the corresponding relationship between the rising displacement of the channel concrete precast block 301 at the center and the edge channel concrete precast block 301 can be monitored in real time.

[0030] The top of the automatic leveling pad 908 is hemispherical. During the loading process of the channel concrete prefabricated block 301, an inclination angle will appear. The automatic leveling pad 908 avoids the tilt of the hydraulic jack.

[0031] The six channel concrete precast blocks 301 are respectively arranged around the central channel concrete precast block 301, and a 2 cm interval is reserved between the central channel concrete precast block 301. The experimental cement mortar 302 is laid in the joints between the central channel concrete precast block 301 and the six channel concrete precast blocks 301 at the edge. The model of the channel concrete precast block 301 is C30, and the model of the cement mortar 302 is M15.

[0032] A force-displacement measuring device is provided at one end of the micrometer fixing bracket 2, and the force-displacement measuring device includes a micrometer, a magnetic base, a fixed rod bracket, a reading microscope, a steel ruler, a pressure sensor and a sensor reader. The pressure sensor is connected to the sensor reader, and the sensor reader records the pressure exerted on the pressure sensor in real time. In addition, a reading microscope and a steel ruler are provided to assist in the measurement.

[0033] The dial gauge fixing bracket 2 is L-shaped, with the shorter side of the bracket fixed on the platform frame baffle 1, and the longer side horizontally located at the upper end of the square hole 7. The dial gauge fixing bracket 2 can rotate with the short side as the axis. Two dial gauges are fixed on the dial gauge fixing bracket 2. The probes of the two dial gauges are respectively arranged at the symmetrical center positions of the channel concrete precast block 301 at the center and the six channel concrete precast blocks 301 at the edge. The two dial gauges respectively record the vertical displacement of the lining plate.

[0034] Working principle: clean the ground and prepare for the subsequent loading test. Select a high-quality channel concrete precast block 301 with smooth and uniform surfaces and place it steadily on the square hole 7 of the support rod frame 5. Align the center line of the test piece with the center line of the square hole 7 and coincide with the axis of the jacking structure 9. Select six channel concrete precast blocks 301 and place them around the central channel concrete precast block 301. The channel concrete precast blocks 301 are spaced two centimeters apart. Pass the bow-shaped limit rod 402 and the limit rod body 401 through the limit rod reserved hole 8 on the platform frame baffle 1. One end is tightly pressed against the channel concrete precast block 301 to limit the slippage of the channel concrete precast block 301. Tighten the limit bolts inside and outside the limit rod reserved hole 8 on the platform frame baffle 1. Fix the bow-shaped limit rod 402 and the limit rod body 401 through the limit bolts. Prepare P·O 42.5 Ordinary Portland cement, medium sand and water are used to prepare M15 mortar in the ratio of 1:4.84:0.84. Lubricating oil is applied to the horizontal support platform at the gap between the precast channel concrete blocks 301 to prevent the mortar from sticking to the support rod frame 5 after solidification. At the same time, be careful not to apply it on the side of the precast channel concrete blocks 301 to avoid affecting the connection between the precast channel concrete blocks 301. The prepared mortar is laid between the gaps of the precast channel concrete blocks 301. The mortar between the gaps should be compacted and filled. The temperature should be about 20 degrees Celsius in a cool place in autumn and the mortar should be cured for seven days.

[0035] After the cement mortar 302 is cured, the mortar cracks between the channel concrete precast blocks 301 are measured and recorded. The first pressure sensor 907 is arranged between the channel concrete precast block 301 and the body 903 at the center. The micrometer and the magnetic base are installed on the micrometer fixing rod frame 2. Other equipment is also ready. Painting with eye-catching white paint will help to observe the generation and development of cracks in the subsequent experimental loading at the first time. A reading microscope can be used for crack observation, and a steel ruler can be used when the cracks are sufficiently developed.

[0036] After the test begins, the load needs to be continuously applied to the specimen at a steady speed to avoid impact loads. The entire loading process should be completed within 3 minutes. Changes in the micrometer readings should be recorded each time the load is applied. At the same time, attention should be paid to the development of cracks, and subsequent changes in cracks, the lifting of precast concrete blocks, and the relative lifting between slabs should be recorded.

[0037] The specimen is determined to be damaged based on the damage of the joint mortar. When the jacking structure 9 is unloaded, it is determined to be damaged. The load and the lifting of the concrete precast block at this time are recorded, and then the loading is continued within the observable range of the device to observe the later damage.

[0038] After the test, observe the failure characteristics of each specimen and take notes. During the experiment and after the specimen is completed, take photos and records of typical failed specimens and the generation and development of failure at any time. The load and displacement information obtained by the force-displacement device is combined with the failure of the specimens in the test to obtain the anti-floating bonding performance of the mortar between the tested precast concrete blocks.

[0039] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An experimental device for uplift pressure loading of concrete channel lining, comprising a platform frame baffle (1), characterized in that: The four diagonal portions of the lower end surface of the platform frame baffle (1) are provided with vertical support legs (6); a support rod frame (5) is provided at the lower part of the inner part of the platform frame baffle (1); a square hole (7) is provided at the center of the upper end surface of the support rod frame (5); an experimental structure (3) is provided on the upper end surface of the support rod frame (5) located above the square hole (7); the experimental structure (3) comprises seven channel concrete prefabricated blocks (301); water pipes are provided between the seven channel concrete prefabricated blocks (301). Mud mortar (302), the center of the two inner side walls of the platform frame baffle (1), the center of the front and rear inner side walls of the platform frame baffle (1) and the center of the front and rear inner side walls of the platform frame baffle (1) are all provided with limit rod reserved holes (8), the upper end surface of the support rod frame (5) is provided with limit structures (4) on both sides, the lower end of the square hole (7) is provided with a lifting structure (9), and the upper end surface of the platform frame baffle (1) is provided with a dial gauge fixing bracket (2) on one side.

2. The experimental device for uplift pressure loading of concrete channel lining according to claim 1 is characterized by: The limiting structure (4) comprises a limiting rod body (401) and a bow-shaped limiting rod (402); the limiting rod body (401) passes through a limiting rod reserved hole (8) on one side and reaches the outside of the platform frame baffle (1); the bow-shaped limiting rod (402) is arranged at the end of the limiting rod body (401) inside the platform frame baffle (1), and the end is attached to a side wall of the experimental structure (3).

3. The experimental device for uplift pressure loading of concrete channel lining according to claim 1 is characterized by: The lifting structure (9) comprises a base plate (901), a lifting control (902), a machine body (903), a claw block (904), a tension spring (905), an anti-slip pad (906), a first pressure sensor (907) and an automatic leveling pad (908); the lifting control (902) is arranged at the front center of the upper end surface of the base plate (901); the machine body (903) is arranged at the center of the upper end surface of the base plate (901); and the claw block (904) is arranged at the front center of the upper end surface of the body. (903) output end, the tension spring (905) is arranged at the upper center of one side wall of the claw block (904), the other end of the tension spring (905) is fixedly connected to the upper end surface of the base plate (901), the anti-skid gasket (906) is arranged on the upper end surface of the claw block (904), the first pressure sensor (907) is arranged on the upper end surface of the anti-skid gasket (906), and the automatic leveling gasket (908) is arranged on the upper end surface of the first pressure sensor (907).

4. The experimental device for uplift pressure loading of concrete channel lining according to claim 3 is characterized by: The top of the automatic leveling gasket (908) is hemispherical.

5. The experimental device for uplift pressure loading of concrete channel lining according to claim 1, characterized in that: The six channel concrete precast blocks (301) are arranged around the central channel concrete precast block (301) respectively, and a 2 cm spacing is reserved between the central channel concrete precast block (301). The test cement mortar (302) is laid in the joints between the central channel concrete precast block (301) and the six channel concrete precast blocks (301) at the edges. The model of the channel concrete precast block (301) is C30, and the model of the cement mortar (302) is M15.

6. The experimental device for uplift pressure loading of concrete channel lining according to claim 1, characterized in that: A force-displacement measuring device is provided at one end of the micrometer fixing bracket (2), and the force-displacement measuring device comprises a micrometer, a magnetic base, a fixing rod bracket, a reading microscope, a steel ruler, a pressure sensor and a sensor reading instrument. The pressure sensor is connected to the sensor reading instrument, and the sensor reading instrument records the pressure applied to the pressure sensor in real time. In addition, a reading microscope and a steel ruler are provided to assist in the measurement.

7. The experimental device for uplift pressure loading of concrete channel lining according to claim 1 is characterized by: The dial gauge fixing bracket (2) is L-shaped, with a shorter side of the bracket fixed on the platform frame baffle (1), and a longer side horizontally located at the upper end of the square hole (7). The dial gauge fixing bracket (2) can rotate with the shorter side as an axis. Two dial gauges are fixed on the dial gauge fixing bracket (2), and the probes of the two dial gauges are respectively arranged at the symmetrical center positions of the channel concrete prefabricated block (301) at the center and the six channel concrete prefabricated blocks (301) at the edge. The two dial gauges respectively record the vertical displacement of the lining plate.

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