CN112268815B - An experimental testing method for ice pullout force of concrete dams in cold areas - Google Patents

Abstract

The invention discloses a test method for ice pulling force of a concrete dam in a cold area, which comprises the following specific processes: step 1, manufacturing a cube concrete test piece; step 2, cutting the cubic concrete test piece into two equal cuboid concrete test pieces, and reserving the cuboid concrete test pieces with the plastering surfaces; step 3, manufacturing an ice cube-concrete mixture test piece by using the reserved cuboid concrete test piece; step 4, placing the ice block-concrete mixture test piece into a shearing box of a low Wen Zhijian instrument; and 5, setting the temperature of a temperature control system in a low Wen Zhijian instrument, standing, setting the pressure in a vertical pressurizing system in a low Wen Zhijian instrument, setting the shearing speed of a horizontal loading system in a low Wen Zhijian instrument, and starting detection to obtain a shearing stress-strain curve of the contact surface of ice cubes and concrete, thereby obtaining the shearing strength of the contact surface of ice cubes and concrete. The testing method can effectively and intuitively measure the shear strength of the contact surface of the concrete and the ice blocks.

Description

An experimental testing method for ice pullout force of concrete dams in cold areas

Technical field

The invention belongs to the technical field of hydraulic structure protection, and specifically relates to a test method for ice pullout force of concrete dams in cold areas.

Background technique

With the continuous development of my country's water conservancy industry, it has become an inevitable trend for the construction of water conservancy projects to develop in alpine and high-altitude areas, such as Tibet, Xinjiang, Sichuan and other places. When building concrete dams in these areas, when the temperature is below 0°C, the reservoir water surface freezes, and the frozen layer freezes with the upstream dam surface. When the incoming flow of the reservoir is less than the outgoing flow, the water level drops, causing the water body to collapse. The frozen layer detaches, and the frozen layer is affected by its own gravity, causing a downward destructive force on the upstream dam surface connected to it. When the inflow flow of the reservoir is greater than the outflow flow, the water level rises, and the water body will produce an upward buoyancy force on the frozen layer, which will produce an upward destructive force on the upstream dam surface. We refer to this kind of damage to the upstream dam surface as It is called ice-drawing damage. Especially in winter, the ice-drawing damage on the upstream dam surface is particularly serious.

In some old water conservancy buildings in severe cold areas in my country, due to the lack of insulation and moisture retention layers, ice-drawing damage directly acts on the concrete, causing serious hidden dangers to the safety and stability of the dam body. Therefore, some measures need to be taken to reduce the damage caused by ice-drawing. . For newly built water conservancy projects in cold and high-altitude areas, due to the installation of corresponding thermal insulation and moisture-retaining layers, ice-drawing damage will act on the thermal insulation and moisture-retaining layers, which can reduce damage to the dam body. However, whether we are taking corresponding measures on old water conservancy buildings or setting up thermal insulation and moisturizing layers on new buildings, corresponding data indicators are needed to guide this to ensure that the damaging effects of ice pulling can be effectively reduced without causing a waste of resources. .

The existing Chinese patent 201710826801.7 discloses a detection box and a detection method for detecting the ice thrust and ice pulling damage of water conservancy buildings caused by freezing of reservoirs, which can effectively measure the ice thrust and ice thrust of water conservancy buildings caused by freezing of water bodies in the laboratory. Test whether the test material can resist damage caused by ice pulling. However, the shear strength of the test material against ice pullout damage could not be measured. In actual situations, the shear strength of the test material against ice pullout damage is an important indicator to measure its performance. Therefore, a testable method is urgently needed. Develop a test method for testing the shear strength of materials against ice pullout damage.

Contents of the invention

The purpose of the present invention is to provide a test method for ice pullout force of concrete dams in cold areas, which can effectively and directly observe the shear strength of the contact surface between concrete and ice.

The technical solution adopted by the present invention is a test method for ice pullout of concrete dams in cold areas, which is specifically implemented according to the following steps:

Step 1, make a cubic concrete specimen;

Step 2: Cut the cubic concrete specimen produced in Step 1 into two rectangular concrete specimens of equal size, and retain the rectangular concrete specimen with a flat surface;

Step 3: Use the cuboid concrete specimen retained in Step 2 to make an ice cube-concrete mixture specimen;

Step 4: Place the ice-concrete mixture specimen produced in Step 3 into the shear box of the low-temperature direct shear instrument;

Step 5: Set the temperature of the temperature control system in the low-temperature direct shear instrument and let it stand. Then set the value in the vertical pressure system in the low-temperature direct shear instrument, and set the shearing speed of the horizontal loading system in the low-temperature direct shear instrument. , start testing, obtain the shear stress strain curve of the contact surface between the ice block and the concrete, and obtain the shear strength of the contact surface between the ice block and the concrete through the shear stress strain curve, that is, the test is completed.

The invention is also characterized by:

Step 1 is implemented according to the following steps:

Step 1.1, use stainless steel mold A with a specification of 100*100*100mm and concrete to make a cubic concrete specimen, and evenly apply a layer of lubricating oil on the inner wall of mold A;

Step 1.2. After step 1.1 is completed, take concrete and mix it evenly. The particle size of the concrete aggregate shall not exceed 25mm;

Step 1.3. Put the concrete obtained in step 1.2 into the mold A processed in step 1.1. Place the mold A filled with concrete on the vibrating table for vibration. During the vibration, mold A must not have any vibration and continue to the surface of the concrete. Until the slurry is released, place a flat steel plate with a thickness of 5mm on the top of the concrete, and use a rubber hammer to hammer it to make the concrete dense and the surface smooth;

Step 1.4: After the concrete processed in step 1.3 is formed for 24 hours, disassemble the mold A to obtain a cubic concrete specimen;

Step 1.5: Put the cubic concrete specimen obtained in step 1.4 into a curing box with a temperature of 20°C and a relative humidity greater than 95% for curing for 28 days and set aside.

Mold A includes a square bottom plate. One set of two adjacent sides of the bottom plate is provided with a first baffle perpendicular to the bottom plate. The other set of two adjacent sides of the bottom plate is provided with a second baffle perpendicular to the bottom plate. Baffles, the first baffle and the bottom plate, the second baffle and the bottom plate are all provided with baffles and bottom plate fixing blocks, adjacent baffles and bottom plate fixing blocks are connected by bolts, the first baffle and the second baffle are adjacent One end of each is provided with a baffle and a baffle fixing block, and adjacent baffles and baffle fixing blocks are connected by bolts.

Step 2 is specifically implemented according to the following steps:

Step 2.1, mark and draw the cutting line along half of the height of the cubic concrete specimen obtained in step 1;

Step 2.2, use a cutting machine to cut along the cutting line drawn in step 2.1 to obtain two cuboid concrete specimens of equal size, and retain the cuboid concrete specimen with a plastered surface.

Step 3 is specifically implemented according to the following steps:

Step 3.1: Disassemble mold A, apply a layer of lubricating oil evenly on the inner wall of mold A, and then stick the plastic wrap evenly and flatly on the inner wall of mold A;

Step 3.2, reassemble mold A, and place the rectangular concrete specimen with the plastered surface obtained in step 2.2 into mold A, with the cut surface facing down and in contact with the bottom plate of mold A, and the plastered surface is in the middle of mold A. ;

Step 3.3: After the hot melt glue gun equipped with the hot melt glue stick is connected to the power supply, preheat it for 5 minutes, and then conduct the joints on the mold A containing the rectangular concrete specimen with the flat surface obtained in step 3.2. To handle, use a hot melt glue gun to spray evenly along the outside of each contact seam of mold A until all seams are sprayed;

Step 3.4: Inject pure water into the mold A processed in step 3.3 until the water surface is level with the top of the mold A;

Step 3.5, put the mold A processed in step 3.4 into a refrigerator at a temperature of -20°C for 10 hours;

Step 3.6: Take out the mold A processed in step 3.4 from the refrigerator, scrape off the ice above the top of mold A, then fix mold A on the concrete grinder, and use the concrete grinder to smooth the scraped surface. to the level with the top of mold A, and obtain the ice cube-concrete mixture specimen;

Step 3.7: Scrape off the hot melt glue sprayed on the joints of mold A. Disassemble mold A. Take out the ice cube-concrete mixture specimen obtained in step 3.6 from the mold. Place the ice cube upward and the concrete toward Place it in a refrigerator at a temperature of -20°C for later use.

The specific process of step 4 is: put the ice cubes of the ice cube-concrete mixture specimen into the upper shear box of the low-temperature direct shear instrument, and put the concrete into the lower shear box of the low-temperature direct shear instrument, so that the ice cubes and The contact interface of the concrete is consistent with the shear planes of the upper and lower shear boxes.

Step 5 is specifically implemented according to the following steps:

Step 5.1, keep the temperature set by the temperature control system in the low-temperature direct shear instrument constant, set different pressures in the vertical pressurization system, start the direct shear instrument for measurement, and then detect the temperature of the ice-concrete mixture specimen at the same temperature. The shear strength of the interface between ice and concrete under different ice thrust forces at different temperatures;

Step 5.2, keep the pressure set by the vertical pressurization system in the low-temperature direct shear instrument unchanged, set the temperature control system to different temperatures, start the direct shear instrument for measurement, and then detect the ice-concrete mixture specimen at the same temperature. Under ice thrust, shear strength of the interface between ice and concrete at different temperatures;

Step 5.3, keep the temperature set by the temperature control system in the low-temperature direct shear instrument unchanged, set different pressures in the vertical pressurization system, repeat step 5.1, keep the pressure set by the vertical pressurization system in the low-temperature direct shear instrument unchanged , set the temperature control system to different temperatures, and repeat step 5.2 to detect the shear strength of the contact surface between ice and concrete under different temperatures and different ice thrusts.

The size of the cubic concrete specimen in step 1 is 100*100*100mm.

The dimensions of the two cuboids in step 2 are 100*100*50mm.

The beneficial effects of the present invention are:

(1) The present invention is a method for testing the ice pullout force of concrete dams in cold areas. The test process is simple and convenient, and the results are easy to implement. It solves the problem that in the past, test materials had to be constructed and verified on actual water conservancy projects, which was very costly and time-consuming. problems and effectively promote laboratory research and applications;

(2) The present invention is a test method for ice pullout of concrete dams in cold areas. It can adjust the pressure of the vertical pressurization system according to the needs to simulate the ice thrust. The temperature of the shear box is adjusted through the temperature control system to reflect the location of different projects. Ambient temperature effectively simulates the shear damage caused by ice pulling on the upstream dam surface of a concrete dam under actual conditions. The measured shear stress-strain curve is intuitive and clear, and the obtained shear strength of the contact surface between ice and concrete is relatively accurate;

(3) The present invention is a method for testing the ice pullout force of concrete dams in cold areas, in which the concrete dam simulation specimens and the ice layer specimens are equivalently produced according to actual working conditions to meet the needs of the test instruments, and the test results can be accurate , intuitively reflects the stress-strain relationship between concrete dams and ice layers in cold areas.

Description of the drawings

Figure 1 is a schematic structural diagram of the ice cube-concrete mixture specimen involved in the experimental testing method of the present invention;

Figure 2 is a schematic diagram of the disassembled structure of mold A involved in the experimental testing method of the present invention;

Figure 3 is a schematic structural diagram of mold A involved in the experimental testing method of the present invention;

Figure 4 is a schematic structural diagram of a low-temperature direct shear instrument used in the experimental testing method of the present invention.

In the picture, 1. The first baffle, 2. The second baffle, 3. The bottom plate, 4. The baffle and the baffle are fixed quickly, 5. The baffle and the bottom plate are fixed, 6. Ice cubes, 7. Concrete, 8 .Device fixing system, 9. Upper shear box, 10. Lower shear box, 11. Vertical pressurization system, 12. Horizontal loading system, 13. Automatic data acquisition system, 14. Temperature control system.

Detailed ways

The present invention will be described in detail below with reference to the drawings and specific embodiments.

The present invention is a method for testing the ice pullout force of concrete dams in cold areas, which is specifically implemented according to the following steps:

Step 1: Make a 100*100*100mm cubic concrete specimen;

Step 1.1, use stainless steel mold A with specifications of 100*100*100mm and concrete to make a cubic concrete specimen. Apply a layer of lubricating oil evenly on the inner wall of mold A. The purpose of applying lubricating oil is to facilitate the removal of concrete from the mold after final setting. A takes out;

As shown in Figures 2 and 3, mold A includes a square bottom plate 3. First baffles 1 are provided on one set of two adjacent sides of the bottom plate 3 and perpendicular to the bottom plate 3. The other set of bottom plates 3 is adjacent to the bottom plate 3. There are second baffles 2 on the two adjacent sides and perpendicular to the bottom plate 3. The first baffle 1 and the bottom plate 3, the second baffle 2 and the bottom plate 3 are all provided with baffles and bottom plate fixing blocks 5, adjacent to each other. The baffle and the bottom plate fixing block 5 are connected by bolts. The adjacent ends of the first baffle 1 and the second baffle 2 are both provided with baffles and baffle fixing blocks 4. The adjacent baffles and the baffle fixing blocks 4 are connected by bolts. connect;

Step 1.2. After step 1.1 is completed, take concrete and mix it evenly. The particle size of the concrete aggregate shall not exceed 25mm;

Step 1.3. Put the concrete obtained in step 1.2 into the mold A processed in step 1.1. Place the mold A filled with concrete on the vibrating table for vibration. During the vibration, mold A must not have any vibration and continue to the surface of the concrete. Until the slurry is released, place a flat steel plate with a thickness of 5mm on the top of the concrete, and use a rubber hammer to hammer it to make the concrete dense and the surface smooth;

Step 1.4: After the concrete processed in step 1.3 is formed for 24 hours, disassemble the mold A to obtain a cubic concrete specimen;

Step 1.5: Put the cubic concrete specimen obtained in step 1.4 into a curing box with a temperature of 20°C and a relative humidity greater than 95% for curing for 28 days and set aside;

Step 2: Cut the cubic concrete specimen produced in Step 1 into two 100*100*50mm rectangular concrete specimens of equal size, and retain the cuboid concrete specimen with a plastered surface;

Step 2.1, mark the cube concrete specimen obtained in step 1 along its height of 50mm and draw the cutting line;

Step 2.2, use a cutting machine to cut along the cutting line drawn in step 2.1 to obtain two 100*100*50mm rectangular concrete specimens of equal size, and retain the cuboid concrete specimen with a plastered surface;

Step 3: Use the cuboid concrete specimen retained in Step 2 to make an ice cube-concrete mixture specimen as shown in Figure 1;

Step 3.1, disassemble mold A, apply a layer of lubricating oil evenly on the inner wall of mold A, and then use plastic wrap to evenly and flatly paste it on the inner wall of mold A (first baffle, second baffle, bottom plate) , to ensure that the plastic wrap is smooth and even. The main function of setting the plastic wrap is to prevent the ice cubes from freezing together with mold A, which makes it difficult to remove the mold;;

Step 3.2, reassemble mold A, and place the rectangular concrete specimen with the plastered surface obtained in step 2 into mold A, with the cut surface facing down and in contact with the bottom plate of mold A, and the plastered surface is in the middle of mold A. , used to simulate the actual situation where the upstream concrete dam surface is vertical and in contact with water. When placing concrete, ensure that the plastic wrap is intact to avoid scratching;

Step 3.3: After the hot melt glue gun equipped with the hot melt glue stick is connected to the power supply, preheat it for 5 minutes, and then conduct the joints on the mold A containing the rectangular concrete specimen with the flat surface obtained in step 3.2. For treatment, use a hot melt glue gun to spray evenly along the outside of each contact seam of mold A until all seams are sprayed to ensure that mold A is well sealed and does not leak;

Step 3.4: Inject pure water into the mold A processed in step 3.3 until the water surface is level with the top of the mold A;

Step 3.5, put the mold A processed in step 3.4 into a refrigerator at a temperature of -20°C for 10 hours;

Step 3.6, take out the mold A processed in step 3.4 from the refrigerator, scrape off the ice above the top of the mold A (excess ice due to expansion), then fix the mold A on the concrete grinder, and use the concrete The grinder smoothes the scraped surface to the level with the top of mold A to obtain an ice-concrete mixture specimen;

Step 3.7: Scrape off the hot melt glue sprayed on the joints of mold A. Disassemble mold A. Take out the ice cube-concrete mixture specimen obtained in step 3.6 from the mold. Place the ice cube upward and the concrete toward Place it in a refrigerator at a temperature of -20°C for later use;

Step 4: Place the ice-concrete mixture specimen produced in Step 3 into the shear box of the low-temperature direct shear instrument;

As shown in Figure 4, the low-temperature direct shear instrument adopts the STY-1000 low-temperature direct shear instrument produced by Sichuan Dexiang Kechuang Instrument Co., Ltd., including an upper shear box 9 and a lower shear box 10 placed up and down. The upper shear box 9 The height of the upper shearing box 9 and the lower shearing box 10 is 50mm. The interface between the upper shearing box 9 and the lower shearing box 10 is the shearing plane. The bottom of the lower shearing box 10 is provided with a device fixing system 8. A temperature control system 14 is provided outside the box 9 and the lower shearing box 10, which can set the temperature during testing. The temperature range of the temperature control system 14 is 0°C to -20°C. The top of the upper shearing box 9 is provided with a vertical Pressurizing system 11 is used to simulate the ice thrust generated during freezing. The pressure can be adjusted by itself. A horizontal loading system 12 is provided on one side of the upper shear box 9. The horizontal loading system 12 is connected to the automatic data acquisition system 13 for measurement. The shear stress-strain curve of the contact interface between ice cube and concrete can be directly obtained;

Put the ice cube 6 of the ice cube-concrete mixture specimen into the upper shear box 9 of the low-temperature direct shear instrument, and the concrete 7 into the lower shear box 10 of the low-temperature direct shear instrument, so that the ice cube 6 and the concrete 7 The contact interface is consistent with the shear plane of the upper shear box 9 and the lower shear box 10;

Step 5: Set the temperature of the temperature control system 14 in the low-temperature direct shear instrument and let it stand for 10 minutes, then set the pressure in the vertical pressure system 11 in the low-temperature direct shear instrument, and set the horizontal loading system 12 in the low-temperature direct shear instrument. The shear speed is 0.8mm/min, start the detection, and obtain the shear stress-strain curve of the contact surface between the ice block and the concrete. The shear strength of the contact surface between the ice block and the concrete is obtained through the shear stress-strain curve;

Step 5.1, keep the temperature set by the temperature control system 14 in the low-temperature direct shear instrument unchanged, set the vertical pressure system 11 to different pressures, start the direct shear instrument for measurement, and then detect the ice-concrete mixture specimen. The shear strength of the interface between ice and concrete under different ice thrust forces at the same temperature;

Step 5.2, keep the pressure set by the vertical pressurization system 11 in the low-temperature direct shear instrument unchanged, set the temperature control system 14 to different temperatures, start the direct shear instrument for measurement, and then detect the ice cube-concrete mixture specimen. Under the same ice thrust, the shear strength of the interface between ice and concrete under different temperatures;

Step 5.3, keep the temperature set by the temperature control system 14 in the low-temperature direct shear instrument unchanged, set the vertical pressurization system 11 to different pressures, repeat step 5.1, and change the pressure set by the vertical pressurization system 11 in the low-temperature direct shear instrument. Remain unchanged, set the temperature control system 14 to different temperatures, and repeat step 5.2 to detect the shear strength of the contact surface between the ice cube and the concrete under different temperatures and different ice thrust forces.

The present invention provides a test method for ice pullout force of concrete dams in cold areas, which can effectively and directly observe the shear strength of the contact surface between concrete and ice. Its principle is as follows:

In actual circumstances, the contact interface between the frozen layer and the concrete upstream dam surface is the weak surface of the overall structure, so the concrete is easily damaged on the contact surface. The shear strength of the contact surface between ice and concrete is It is an important indicator to measure its structural stability, so it is necessary to measure the shear strength of the contact surface between the two. By simulating the freezing of natural water and concrete dam surfaces in the laboratory, ice cube-concrete mixture specimens can be prepared, and then equipped with upper shear box, lower shear box, vertical pressurization system, and horizontal loading System, temperature control system, and low-temperature direct shear instrument of the automatic data acquisition system conduct direct shear tests on ice-concrete mixture specimens. Among them, the temperature control system can adjust different temperatures and can simulate different temperatures under actual conditions; vertical The pressurization system can adjust different pressures and simulate the different ice thrusts exerted by ice on the concrete dam surface in actual situations; the horizontal loading system is used to simulate the effects of its own gravity on the ice and the buoyancy of the water on the ice in actual situations. During the shearing process, it is assumed that the ice cube and the concrete are both rigid bodies, and neither deforms. Only the displacement occurs at the contact surface between the two. The horizontal loading system is connected to the automatic data acquisition system, and the shear stress can be drawn by itself. -Strain curve, and finally the shear strength of the contact surface between ice cube and concrete can be obtained.

The invention provides an experimental testing method for the ice pullout force of concrete dams in cold areas, which can effectively and directly observe the shear strength of the contact surface between concrete and ice, is simple to operate, easy to implement, and can self-regulate the pressure of the vertical pressurization system according to needs. It is used to simulate the ice thrust, and the temperature is adjusted in the temperature control system, which can effectively simulate the shear damage caused by ice pulling on the upstream dam surface of the concrete dam under actual conditions. The measured shear stress-strain curve is intuitive and clear, and the obtained The shear strength of the contact surface between ice and concrete is relatively accurate, which can effectively avoid the unsatisfactory effect of the anti-ice pullout device or the waste of resources caused by the lack of corresponding data indicators in the past.

Claims (7)

1. The test method for the ice pulling force of the concrete dam in the cold area is characterized by comprising the following steps of:

step 1, manufacturing a cube concrete test piece;

the step 1 is specifically implemented according to the following steps:

step 1.1, manufacturing a cubic concrete test piece by using a stainless steel die A with the specification of 100mm and concrete, and uniformly coating a layer of lubricating oil on the inner wall of the die A;

step 1.2, after the step 1.1 is completed, taking concrete and uniformly stirring, wherein the particle size of concrete aggregate is not more than 25mm;

step 1.3, placing the concrete obtained in the step 1.2 into a die A treated in the step 1.1, placing the die A with the concrete into a vibrating table for vibrating, keeping the die A without beating until the surface of the concrete is pulped, and then filling a flat steel plate with the thickness of 5mm on the top of the concrete, hammering the concrete by using a rubber hammer to compact the concrete and make the surface flat;

step 1.4, after the concrete processed in the step 1.3 is molded into 24h, the die A is disassembled to obtain a cubic concrete test piece;

step 1.5, placing the cubic concrete test piece obtained in the step 1.4 into a curing box with the temperature of 20 ℃ and the relative humidity of more than 95% for curing for 28 days for later use;

step 2, cutting the cubic concrete test piece manufactured in the step 1 into two cuboid concrete test pieces with equal sizes, and reserving the cuboid concrete test pieces with the trowelling surfaces in the cuboid concrete test pieces;

step 3, manufacturing an ice cube-concrete mixture test piece by using the cuboid concrete test piece reserved in the step 2;

the step 3 is specifically implemented according to the following steps:

step 3.1, disassembling the die A, uniformly coating a layer of lubricating oil on the inner wall of the die A, and uniformly and flatly attaching a preservative film on the inner wall of the die A;

step 3.2, reassembling the die A, and placing the cuboid concrete test piece with the plastering surface obtained in the step 2 into the die A, wherein the cutting surface is placed downwards and is contacted with the bottom plate of the die A, and the plastering surface is positioned in the middle of the die A;

step 3.3, after the hot melt adhesive gun with the hot melt adhesive rod is powered on, preheating for 5 minutes, then treating the joint of the die A with the cuboid concrete test piece with the plastering surface obtained in the step 3.2, and uniformly spraying along the outer part of each contact joint of the die A by using the hot melt adhesive gun until all joints are sprayed;

step 3.4, injecting purified water into the die A treated in the step 3.3 to the water surface and the top level of the die A;

step 3.5, putting the die A treated in the step 3.4 into a refrigerator with the temperature of minus 20 ℃ to be frozen for 10 hours;

step 3.6, taking the die A processed in the step 3.4 out of the refrigerator, scraping ice higher than the top of the die A, fixing the die A on a concrete grinding machine, and grinding the scraped surface to be horizontal to the top of the die A by using the concrete grinding machine to obtain an ice block-concrete mixture test piece;

step 3.7, scraping the hot melt adhesive sprayed at the joint of the die A, disassembling the die A, taking out the ice block-concrete mixture test piece obtained in the step 3.6 from the die, upwards placing the ice block, and downwards placing the concrete in a refrigerator with the temperature of-20 ℃ for later use;

step 4, placing the ice cube-concrete mixture test piece manufactured in the step 3 into a shearing box of a low Wen Zhijian instrument;

setting the temperature of a temperature control system (14) in a low Wen Zhijian instrument, standing, setting the pressure in a vertical pressurizing system (11) in a low Wen Zhijian instrument, setting the shearing speed of a horizontal loading system (12) in a low Wen Zhijian instrument, starting detection, obtaining a shearing stress-strain curve of the contact surface of ice cubes and concrete, and obtaining the shearing strength of the contact surface of ice cubes and concrete through the shearing stress-strain curve, thus completing the test;

the step 5 is specifically implemented according to the following steps:

step 5.1, keeping the temperature set by a temperature control system (14) in the low-temperature direct shear device unchanged, setting different pressures by a vertical pressurizing system (11), and starting the direct shear device to measure, so that the shearing strength of the interface between the ice and the concrete under the action of different ice thrusts can be detected when the ice-concrete mixture test piece is at the same temperature;

step 5.2, the pressure set by the vertical pressurizing system (11) in the low-temperature direct shear apparatus is kept unchanged, the temperature control system (14) is set at different temperatures, and the direct shear apparatus is started to measure, so that the shearing strength of the interface between the ice and the concrete under the same ice thrust and different temperatures can be detected;

and 5.3, keeping the temperature set by a temperature control system (14) in the low-temperature direct shear device unchanged, setting different pressures by a vertical pressurizing system (11), repeating the step 5.1, keeping the pressure set by the vertical pressurizing system (11) in the low-temperature direct shear device unchanged, setting different temperatures by the temperature control system (14), and repeating the step 5.2, thereby detecting the shearing strength of the contact surface of ice cubes and concrete under the action of different ice thrusts at different temperatures.

2. The test method for the ice pulling force of the concrete dam in the cold area according to claim 1, wherein the die A comprises a square bottom plate (3), a first baffle (1) is arranged on one group of two adjacent edges of the bottom plate (3) and perpendicular to the bottom plate (3), a second baffle (2) is arranged on the other group of two adjacent edges of the bottom plate (3) and perpendicular to the bottom plate (3), baffle and bottom plate fixing blocks (5) are arranged on the first baffle (1) and the bottom plate (3) and on the second baffle (2) and the bottom plate (3), adjacent baffle and bottom plate fixing blocks (5) are connected through bolts, baffle and baffle fixing blocks (4) are arranged at one ends, adjacent to the first baffle (1) and the second baffle (2), and the adjacent baffle and baffle fixing blocks (4) are connected through bolts.

3. The method for testing the ice pulling force of the concrete dam in the cold area according to claim 1, wherein the step 2 is specifically implemented according to the following steps:

step 2.1, marking the cube concrete test piece obtained in the step 1 along a half of the height of the cube concrete test piece and drawing cutting lines;

and 2.2, cutting along the cutting line drawn in the step 2.1 by using a cutting machine to obtain two cuboid concrete test pieces with equal sizes, and reserving the cuboid concrete test pieces with the trowelling surfaces.

4. The method for testing the ice pulling force of the concrete dam in the cold area according to claim 1, wherein the specific process of the step 4 is as follows: the ice cubes (6) of the ice cube-concrete mixture test piece are placed in an upper shearing box (9) of a low Wen Zhijian instrument, and the concrete is placed in a lower shearing box (10) of a low Wen Zhijian instrument, so that the contact interface of the ice cubes (6) and the concrete (7) is kept consistent with the shearing planes of the upper shearing box (9) and the lower shearing box (10).

5. The method for testing ice pulling force of concrete dams in cold regions according to claim 1, wherein the dimensions of the cubic concrete test pieces in step 1 are 100 x 100mm.

6. The method for testing ice pulling force of concrete dams in cold regions according to claim 1, wherein the dimensions of the two rectangular solids in step 2 are 100×100×50mm.

7. The method for testing ice pulling force of concrete dams in cold regions according to claim 1, wherein in step 5, the standing time is 10min, and the shearing speed is 0.8mm/min.