Testing device and method for researching interaction between ice and structure of reservoir in cold region

Abstract

The invention discloses a test device and method for researching interaction between ice and a structure of a reservoir in a cold region. The test device comprises I-shaped steel, a pier, a circular pile casing, an arc-shaped bracket, a jack and a guyed displacement sensor, one end of the I-steel is in transmission connection with the pier; the circular pile casing is correspondingly arranged on the outer side portion of the pier in a surrounding mode so that a water body with the preset height can be stored in the circular pile casing, and the temperature can be adjusted and controlled to form an ice layer frozen on the pier. One end of the arc-shaped bracket is in transmission connection with the circular pile casing; the jack is positioned between the other end of the arc-shaped bracket and the other end of the I-shaped steel; one end of the stay wire type displacement sensor is adsorbed and positioned on the outer side of the circular pile casing, and the other end of the stay wire type displacement sensor is adsorbed and positioned on the pier so as to measure the relative actual displacement of the pier. The technical problem that in the prior art, the structural design value of the cold region is inaccurate is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cold region hydraulic structures, and in particular to a test device and method for studying the interaction between ice and structures in cold region reservoirs. Background Art

[0002] Currently, the interaction between ice and structures is a significant research topic in cold-region reservoir projects. Ice in reservoirs expands, freezes, and cracks due to temperature fluctuations, posing a potential threat to the safety of hydraulic structures, particularly upright structures such as bridge piers. To investigate the interaction mechanisms between ice and piers, it is necessary to design appropriate test rigs and conduct systematic rig testing. Existing research typically analyzes the mechanical behavior of ice and its impact on structures through field observations or laboratory simulations. However, these methods lack sufficient design, loading methods, and data acquisition to fully reflect the complexities of actual engineering projects. For example, traditional test rigs often overlook the effects of ice freezing forces, resulting in discrepancies between test results and actual conditions. Furthermore, the impact of factors such as ice thickness and pier shape on ice loads has not been fully investigated, lacking systematic parameter analysis and theoretical model support.

[0003] Therefore, how to accurately evaluate the interaction between ice and bridge piers through experiments and numerical simulations, and establish a more realistic ice load calculation model, has become a technical problem that needs to be solved urgently. Summary of the Invention

[0004] To this end, this invention provides a test apparatus and method for studying ice-structure interactions in cold-region reservoirs. This method combines apparatus testing with numerical simulation to determine load-displacement relationships and cracking characteristics under different operating conditions. Furthermore, a correction factor is introduced to account for the influence of freezing forces, improving the accuracy of ice load predictions. This addresses the technical issue of inaccurate design values ​​for cold-region structures in existing technologies.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] An experimental device for studying the interaction between ice and structure in cold region reservoirs, comprising:

[0007] I-beams, bridge piers, circular casings, curved supports, jacks, and cable-type displacement sensors;

[0008] One end of the I-beam is drivingly connected to the bridge pier;

[0009] The circular casing is correspondingly arranged around the outer side of the bridge pier, so that water of a preset height is accumulated inside the circular casing and the temperature is controlled to form an ice layer frozen on the bridge pier;

[0010] One end of the arc-shaped bracket is drivingly connected to the circular casing;

[0011] The jack is positioned between the other end of the arc-shaped bracket and the other end of the I-beam;

[0012] One end of the draw-wire displacement sensor is adsorbed and positioned on the outside of the circular casing, and the other end of the draw-wire displacement sensor is adsorbed and positioned on the bridge pier to measure the relative actual displacement of the bridge pier.

[0013] On the basis of the above technical solution, the present invention is further described as follows:

[0014] As a further embodiment of the present invention,

[0015] The bridge piers are configured as circular or square piers;

[0016] The outer wall of the circular pier and the outer wall of the square pier are both provided with threaded holes, and the circular pier or the square pier is fixed to one end of the I-beam through the threaded holes and bolt rods.

[0017] As a further embodiment of the present invention, the present invention further comprises:

[0018] A straight plate bracket is fixed to the bottom of the other end of the I-beam, and the straight plate bracket and the other end of the arc-shaped bracket are arranged correspondingly at intervals;

[0019] The pressure sensor is arranged horizontally with the jack and positioned and installed at the interval between the other end of the arc-shaped bracket and the straight plate bracket.

[0020] As a further embodiment of the present invention,

[0021] The jack, the pressure sensor and the center of the ice layer are in a straight line;

[0022] The jack outputs a top pressure load based on the arc-shaped support and applies it to the straight plate support, and further transmits the force to the circular pier or the square pier through the I-beam, thereby pushing the circular pier or the square pier to move relative to the ice layer.

[0023] As a further embodiment of the present invention, the present invention further comprises:

[0024] There are two groups of rollers, the top plate of the arc-shaped bracket has a thickness of at least 20 mm, and the two groups of rollers are placed between the top plate of the arc-shaped bracket and the bottom of the I-beam.

[0025] As a further embodiment of the present invention, the present invention further comprises:

[0026] A drain pipe is installed on one side of the circular casing facing the jack, and a heating rod and a temperature sensor are provided inside the drain pipe. The heating rod can cooperate with the temperature sensor to reach a set temperature to melt the ice in the drain pipe and partially drain the water, thereby releasing the pressure caused by the expansion of the ice volume.

[0027] As a further embodiment of the present invention, the present invention further comprises:

[0028] The temperature chain is made of several pt100 sensors, with a distance of 50 mm between two adjacent pt100 sensors. Several of the pt100 sensors are positioned and inserted into the circular casing 5 to monitor the temperature changes of the ice layer in real time and estimate the thickness of the ice layer.

[0029] A test method for the test device for studying the interaction between ice and structure in cold region reservoirs includes the following steps:

[0030] Use a water pump to draw water, and control the water level inside the circular casing to be 100mm lower than the top of the circular casing to reserve the expansion volume of the ice. Position the drain pipe on the outer wall of the circular casing facing the jack to ensure that it does not affect the deformation of the pressure side. Place a temperature sensor and a heating rod inside the drain pipe. The temperature sensor is placed 10mm below the water surface, and the heating temperature is set to 0℃ to 5℃ to release the expansion pressure in time during the freezing process of the ice layer.

[0031] Hang a weight on one end of a scaled nickel wire rope and place it in water for subsequent ice thickness measurement. The nickel wire rope has millimeter-level accuracy. Lift the weight to the bottom of the ice to read the ice thickness.

[0032] During the freezing process, the temperature chain monitors the temperature changes of the ice layer in real time. The distance between adjacent measuring points is 50mm. The temperature data of each layer of ice is recorded to estimate the ice thickness and analyze the ice temperature distribution.

[0033] One end of the cable-type displacement sensor is attached to the outside of the circular casing, and the other end is attached to the circular or square pier to measure the actual displacement of the circular or square pier relative to the circular casing. The cable-type displacement sensor and pressure sensor are connected to a data acquisition box, which is then connected to a computer for real-time readings. Before the test begins, the initial readings of the pressure sensor and cable-type displacement sensor are calibrated. Then, a jack is activated to apply a load to the straight plate support via a pressure pump. The force is then transmitted to the circular or square pier via the I-beam, causing the circular or square pier to move relative to the ice layer.

[0034] Stop loading when the actual displacement of the circular or square pier relative to the circular casing reaches 50 mm, record the changing trend of the load-displacement curve, and measure the actual thickness of the ice layer with a caliper;

[0035] After the test, the heating rod in the drain pipe is started to melt the ice layer, and the I-beam is restored to its original position through the tripod. The next test will be carried out when the thickness of the ice layer reaches the predetermined requirement.

[0036] As a further solution of the present invention, the following steps are also included:

[0037] During the test observation process, as the jack pushed, the load gradually increased, and relative displacement occurred between the ice layer and the circular or square piers, causing cracks in the ice surface.

[0038] The displacement corresponding to the peak load of the circular piers was recorded, verifying that the ultimate bearing capacity increased significantly with increasing ice thickness. The peak load of the square piers occurred earlier than that of the circular piers and decreased faster.

[0039] A freezing force model is constructed, that is, the freezing strength between the ice layer and the circular or square bridge pier is related to the surface roughness of the pier. The freezing force model is used to describe the freezing force when the ice layer interacts with the bridge pier.

[0040] The mathematical expression of the freezing force model is:

[0041] F f =A·τ f =A·(μ·σ n +c)

[0042] Among them: F f : Total freezing force (kN)

[0043] A: Ice-pier contact area (m 2 )

[0044] τ f :Freezing strength (kPa)

[0045] μ: Friction coefficient (related to the surface roughness of the bridge pier)

[0046] σ n : Normal stress (kPa)

[0047] c: Cohesion (kPa, related to ice thickness and temperature).

[0048] As a further solution of the present invention, the following steps are also included:

[0049] Obtain load-displacement curves and calculation results of the first ice load peak for circular and square piers under different pier cross-sections and different ice thickness conditions, and further obtain load-displacement curves and calculation results of the second ice load peak corresponding to the above curves and calculation results considering the freezing force model;

[0050] For circular piers, when the ice thickness is 5 cm, 10 cm, and 15 cm, the difference between the second ice load peak value of the model considering freezing force and the first ice load peak value of the model not considering freezing force is 4.2%, -1.8%, and -3.8%, respectively. For square piers, when the ice thickness is 10 cm and 15 cm, the difference between the second ice load peak value and the first ice load peak value is -3.5% and -3.4%, respectively, and the difference is within 5%.

[0051] Furthermore, the standard calculated value G of ice load for different pier cross-sections under different ice layer thicknesses, the model calculated value N without considering freezing force, and the model calculated value F with considering freezing force were introduced. Comparing the above data, the ratio N / G of the peak ice load calculated without considering freezing force to the standard calculated value fluctuated around 1. Meanwhile, the ratio F / N of the peak ice load calculated with freezing force to the calculated value without considering freezing force fluctuated within a certain range, with the circular cross-section fluctuating around 1.63 and the square cross-section fluctuating around 1.49.

[0052] To this end, the coefficient ξ is introduced to consider the influence of freezing force, and the following formula is established for correction:

[0053] F=ξαDhσ c

[0054] Where F is the static ice pressure of the bridge pier frozen in the ice layer; ξ is the correction factor considering the influence of the cross-section, which is 1.64 for circular cross-sections and 1.49 for square cross-sections; D is the width of the extrusion surface where the ice layer directly contacts the bridge pier and produces an extrusion effect; h is the ice thickness; σ c is the uniaxial compressive strength of ice; α is the shape coefficient of the pier front edge.

[0055] The present invention has the following beneficial effects:

[0056] 1. In terms of test device design, the stability of the loading system and the accuracy of the measurement data are ensured by rationally arranging components such as I-beams, rollers, and pressure sensors. The combined design of the drainage pipe and the heating rod effectively solves the problem of ice volume expansion and avoids the formation of ice surface bulges or cracks.

[0057] 2. Optimizing the test method allows for accurate simulation of the mechanical behavior of bridge piers under varying ice thicknesses, loading rates, and shapes. Key data, such as ice cracking and load-displacement relationships, can be obtained, providing a theoretical basis and technical support for the design of hydraulic structures in cold regions. This invention is suitable for the design and research of reservoirs, bridges, and other hydraulic structures in cold regions, and has broad application value and potential for widespread adoption. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0059] Figure 1 A schematic diagram of the overall axonometric structure of a test device for studying the interaction between ice and structures in cold region reservoirs provided by an embodiment of the present invention.

[0060] Figure 2 One of the schematic diagrams for measuring and analyzing the load-displacement relationship in the experimental method for studying the interaction between ice and structure in cold region reservoirs provided by an embodiment of the present invention;

[0061] Figure 3 The second schematic diagram of the load-displacement relationship measurement and analysis in the experimental method for studying the interaction between ice and structure in cold region reservoirs provided by an embodiment of the present invention;

[0062] Figure 4 The third schematic diagram of the measurement and analysis of the load-displacement relationship in the experimental method for studying the interaction between ice and structure in cold region reservoirs provided by an embodiment of the present invention.

[0063] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0064] 1. I-beam; 2. Circular bridge pier; 3. Square bridge pier; 31. Threaded hole; 4. Straight plate bracket; 5. Circular casing; 6. Arc bracket; 7. Roller; 8. Drain pipe; 9. Pressure sensor; 10. Temperature chain; 11. Jack; 12. Wire-type displacement sensor. DETAILED DESCRIPTION

[0065] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0066] The terms "upper", "lower", "left", "right", "middle", etc. used in this specification are only for the convenience of description and are not intended to limit the scope of the present invention. Changes or adjustments to their relative relationships should be regarded as within the scope of the present invention without substantially changing the technical content.

[0067] like Figures 1 to 4 As shown, embodiments of the present invention provide a test apparatus and method for studying ice-structure interactions in cold-region reservoirs. The core of this method is to comprehensively study the mechanical behavior of bridge piers in different ice environments through the rational design of the test apparatus and loading system, combined with precise measurement methods and numerical simulation analysis. The specific implementation process of this invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0068] S1: Assembly and debugging phase of the test device.

[0069] Please refer to Figure 1 The test device includes an I-beam 1, a circular pier 2, a square pier 3, a straight plate support 4, a circular casing 5, an arc support 6, a roller 7, a drain pipe 8, a pressure sensor 9, a temperature chain 10, a jack 11 and a wire-type displacement sensor 12.

[0070] First, the I-beam 1, with a length of 4150 mm and a longitudinal cross-sectional dimension of 600 mm × 500 mm × 20 mm, serves as the core load-transmitting structure of the entire test apparatus. Threaded holes 31 are provided on the outer walls of the circular pier 2 and the square pier 3. These holes are then secured to one end of the I-beam 1 using bolts fitted into the holes. This ensures relative stability between the I-beam 1 and the circular pier 2 or pier 3, creating a transmission mechanism. The other end of the I-beam 1 is secured to a straight plate bracket 4, ensuring a clear and stable load transfer path.

[0071] The diameter and height of the circular casing 5 are set to Φ2500mm×600mm, and the wall thickness is set to 5mm. Its bottom is welded to the upper part of the base, and the circular casing 5 is correspondingly arranged around the outer side of the circular pier 2 or the square pier 3 to accumulate water of a preset height inside the circular casing 5 and control the temperature to form an ice layer.

[0072] One end of the curved support 6 is fixed to the outer wall of one side of the circular casing 5, and a stiffening rib is fixed to the web of the curved support 6 to enhance the overall structural rigidity. The other end of the curved support 6 is spaced correspondingly between the straight support 4. A jack 11 and a pressure sensor 9 are horizontally arranged and positioned in the gap between the other end of the curved support 6 and the straight support 4. The jack 11, pressure sensor 9, and the center of the ice layer are aligned. The jack 11 outputs a top pressure load based on the curved support 6 and applies it to the straight support 4. This force is further transmitted to the circular pier 2 or square pier 3 through the I-beam 1, thereby pushing the circular pier 2 or square pier 3 to move relative to the ice layer. The top pressure load output by the jack 11 based on the curved support 6 can be detected in real time by the pressure sensor 9.

[0073] The top plate thickness of the arc-shaped bracket 6 is 20 mm. Two sets of rollers 7 with diameters and lengths corresponding to Φ40 mm × 700 mm are placed between the top plate of the arc-shaped bracket 6 and the bottom of the I-beam 1 to reduce the friction when the I-beam 1 moves, thereby improving the stability of the loading system.

[0074] The drain pipe 8 is installed on one side of the circular casing 5 facing the jack 11, and a heating rod and a temperature sensor are provided inside the drain pipe 8. The heating rod can cooperate with the temperature sensor to reach the set temperature to melt the ice in the drain pipe 8 and partially drain the water, thereby releasing the pressure caused by the expansion of the ice volume and preventing the ice surface from bulging or cracking.

[0075] The temperature chain 10 is made of several pt100 sensors, with a distance of 50 mm between two adjacent pt100 sensors. It is positioned and inserted into the circular casing 5 to monitor the temperature changes of the ice layer in real time and estimate the thickness of the ice layer.

[0076] One end of the wire displacement sensor 12 is adsorbed and positioned on the outside of the circular casing 5, and the other end of the wire displacement sensor 12 is adsorbed and positioned on the circular pier 2 or the square pier 3 to measure the relative actual displacement of the circular pier 2 or the square pier 3.

[0077] S2: Preparation stage for trial implementation.

[0078] A water pump draws water from the reservoir, keeping the water level inside the circular casing 5 100mm below the top to allow for ice expansion. A drain pipe 8 is positioned on the outer wall of the circular casing 5, facing the jack 11, to ensure deformation on the pressure-bearing side is not affected. A temperature sensor and a heater are placed inside the drain pipe 8. The temperature sensor is placed 10mm below the water surface, and the heating temperature is set between 0°C and 5°C to promptly release expansion pressure during ice formation. Simultaneously, a weight is attached to one end of a graduated nickel wire rope and placed in water for subsequent ice thickness measurement. The nickel wire rope has millimeter-level accuracy, and the ice thickness can be read by lifting the weight to the bottom of the ice. Furthermore, during the freezing process, a temperature chain 10 monitors ice temperature changes in real time, with 50mm spacing between adjacent measuring points. Temperature data for each layer of ice is recorded for ice thickness estimation and temperature distribution analysis.

[0079] S3: Specific steps in the experimental operation phase.

[0080] One end of the cable displacement sensor 12 is attached to the outside of the circular casing 5, and the other end of the cable displacement sensor 12 is attached to the circular pier 2 or the square pier 3 to measure the actual displacement of the circular pier 2 or the square pier 3 relative to the circular casing 5. The cable displacement sensor 12 and the pressure sensor 9 are connected to the data acquisition box, which is then connected to the computer for real-time readings. Before the test begins, check whether the installation positions of all components are correct, ensure that there is no jamming in the loading system, and calibrate the initial readings of the pressure sensor 9 and the cable displacement sensor 12. Subsequently, start the jack 11 to lift the load through the pressure pump, apply the load to the straight plate bracket 4, and transmit the force to the circular pier 2 or the square pier 3 through the I-beam 1, pushing the circular pier 2 or the square pier 3 to move relative to the ice layer.

[0081] After measuring the actual displacement of the circular pier 2 or the square pier 3 relative to the circular casing 5 to be 50 mm, stop loading, record the changing trend of the load-displacement curve, and measure the actual thickness of the ice layer with a caliper.

[0082] After the test, the heating rod is started to melt the ice layer, and the I-beam 1 is restored to its original position through the tripod. The next test is carried out when the thickness of the ice layer reaches the predetermined requirement.

[0083] S4: Observation and analysis of ice cracking phenomena.

[0084] During the test observation process, with the pushing action of the jack 11, the load gradually increased, and relative displacement occurred between the ice layer 16 and the circular pier 2 or the square pier 3, resulting in cracks on the ice surface.

[0085] For example, for circular pier 2, when the ice thickness was 5 cm, as the pier displacement increased, the initial cracking appeared as multiple initial vertical cracks (including annular cracks), eventually forming a crushing zone accompanied by buckling. When the ice thickness reached 10 cm, the initial cracks were symmetrically located left and right along the centerline of I-beam 1. As the displacement of circular pier 2 increased, a larger crushing zone formed, with intersecting annular and vertical cracks. The ice crushing process was captured by a camera, and the location and distribution of the cracks were recorded. The damage mechanism of the ice was further analyzed based on the positional status data.

[0086] S5: Measurement and analysis of load-displacement relationships.

[0087] Please refer to Figures 2 to 4 The displacement corresponding to the peak load of circular pier 2 was recorded, verifying that the ultimate bearing capacity increases significantly with increasing ice thickness. For example, the ultimate bearing capacity of 5cm thick ice is 68.3kN, while the ultimate bearing capacity of 10cm and 15cm thick ice is 163.9kN and 287.2kN, respectively.

[0088] The load peak of square pier 3 occurs earlier and decreases faster than that of circular pier 2. For example, the ultimate bearing capacity of a 10cm thick ice layer is 212.3kN, while that of a 15cm thick ice layer is 364.2kN.

[0089] A freezing force model is constructed, that is, the freezing strength between the ice layer and the circular pier 2 or the square pier 3 is related to the surface roughness of the pier. The freezing force model is used to describe the freezing force when the ice layer interacts with the pier.

[0090] The mathematical expression of the freezing force model is:

[0091] F f =A·τ f =A·(μ·σ n +c)

[0092] Among them: F f : Total freezing force (kN)

[0093] A: Ice-pier contact area (m 2 )

[0094] τ f :Freezing strength (kPa)

[0095] μ: Friction coefficient (related to the surface roughness of the bridge pier)

[0096] σ n : Normal stress (kPa)

[0097] c: Cohesion (kPa, related to ice thickness and temperature).

[0098] S7: Comparative analysis of ice load peak calculation results.

[0099] The load-displacement curves and the calculation results of the first ice load peak value for circular pier 2 and square pier 3 under different pier cross-sections and different ice thickness conditions are obtained respectively. Furthermore, the load-displacement curves and the calculation results of the second ice load peak value corresponding to the above curves and calculation results considering the freezing force model are further obtained.

[0100] For circular pier 2, when the ice thickness is 5 cm, 10 cm, and 15 cm, the difference between the second ice load peak value considering the freezing force model and the first ice load peak value without considering the freezing force model is 4.2%, -1.8%, and -3.8%, respectively; for square pier 3, when the ice thickness is 10 cm and 15 cm, the difference between the second ice load peak value and the first ice load peak value is -3.5% and -3.4%, respectively, and the differences are all within 5%.

[0101] We further introduce the standard calculated values ​​G of ice loads for different pier sections under different ice thicknesses, the calculated values ​​N without considering the freezing force model, and the calculated values ​​F with considering the freezing force model, as noted in the "Code for Load Design of Hydraulic Structures" (SL744-2016). Comparing the above data, the ratio N / G of the peak ice load calculation result without considering the freezing force to the standard calculated result fluctuates around 1. Meanwhile, the peak ice load with considering the freezing force and the calculated result without considering the freezing force, F / N, fluctuate within a certain value, with the circular section fluctuating around 1.63 and the square section fluctuating around 1.49. Therefore, it can be assumed that there is a certain ratio relationship between the peak ice load with considering the freezing force and the calculated result of the "Code for Load Design of Hydraulic Structures" (SL744-2016). By introducing the coefficient ξ to consider the influence of the freezing force, the following standard formula is established for correction:

[0102] F=ξαDhσ c

[0103] Where F is the static ice pressure of the bridge pier frozen in the ice layer; ξ is the correction factor considering the influence of the cross-section, which is 1.64 for circular cross-sections and 1.49 for square cross-sections; D is the width of the extrusion surface where the ice layer directly contacts the bridge pier and produces an extrusion effect; h is the ice thickness; σ c is the uniaxial compressive strength of ice; α is the shape coefficient of the pier front edge.

[0104] Through the above implementation process, the present invention realizes a systematic study of bridge piers of different shapes under various ice thicknesses and loading rates, obtains key data such as ice cracking phenomenon and load-displacement relationship, and provides a theoretical basis and technical support for the design of hydraulic structures in cold regions.

[0105] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A test device for studying the interaction between ice and structure in cold region reservoirs, characterized in that: include: I-beams, bridge piers, circular casings, curved supports, jacks, and cable-type displacement sensors; One end of the I-beam is drivingly connected to the bridge pier; The circular casing is correspondingly arranged around the outer side of the bridge pier, so that water of a preset height is accumulated inside the circular casing and the temperature is controlled to form an ice layer frozen on the bridge pier; One end of the arc-shaped bracket is drivingly connected to the circular casing; The jack is positioned between the other end of the arc-shaped bracket and the other end of the I-beam; One end of the draw-wire displacement sensor is adsorbed and positioned on the outside of the circular casing, and the other end of the draw-wire displacement sensor is adsorbed and positioned on the bridge pier to measure the relative actual displacement of the bridge pier.

2. The test device for studying the interaction between ice and structure in cold region reservoirs according to claim 1, characterized in that: The bridge piers are configured as circular or square piers; The outer wall of the circular pier and the outer wall of the square pier are both provided with threaded holes, and the circular pier or the square pier is fixed to one end of the I-beam through the threaded holes and bolt rods.

3. The test device for studying the interaction between ice and structure in cold region reservoirs according to claim 2, characterized in that: Also includes: A straight plate bracket is fixed to the bottom of the other end of the I-beam, and the straight plate bracket and the other end of the arc-shaped bracket are arranged correspondingly at intervals; The pressure sensor is arranged horizontally with the jack and positioned and installed at the interval between the other end of the arc-shaped bracket and the straight plate bracket.

4. The test device for studying the interaction between ice and structure in cold region reservoirs according to claim 3, characterized in that: The jack, the pressure sensor and the center of the ice layer are in a straight line; The jack outputs a top pressure load based on the arc-shaped support and applies it to the straight plate support, and further transmits the force to the circular pier or the square pier through the I-beam, thereby pushing the circular pier or the square pier to move relative to the ice layer.

5. The test device for studying the interaction between ice and structure in cold region reservoirs according to claim 4, characterized in that: Also includes: There are two groups of rollers, the top plate of the arc-shaped bracket has a thickness of at least 20 mm, and the two groups of rollers are placed between the top plate of the arc-shaped bracket and the bottom of the I-beam.

6. The test device for studying the interaction between ice and structure in cold region reservoirs according to claim 4, characterized in that: Also includes: A drain pipe is installed on one side of the circular casing facing the jack, and a heating rod and a temperature sensor are provided inside the drain pipe. The heating rod can cooperate with the temperature sensor to reach a set temperature to melt the ice in the drain pipe and partially drain the water, thereby releasing the pressure caused by the expansion of the ice volume.

7. The test device for studying the interaction between ice and structure in cold region reservoirs according to claim 6, characterized in that: Also includes: The temperature chain is made of several pt100 sensors, with a distance of 50 mm between two adjacent pt100 sensors. Several of the pt100 sensors are positioned and inserted into the circular casing 5 to monitor the temperature changes of the ice layer in real time and estimate the thickness of the ice layer.

8. A test method for a test device for studying the interaction between ice and structures in cold region reservoirs according to claim 7, characterized in that: The steps include: Use a water pump to draw water, and control the water level inside the circular casing to be 100mm lower than the top of the circular casing to reserve the expansion volume of the ice. Position the drain pipe on the outer wall of the circular casing facing the jack to ensure that it does not affect the deformation of the pressure side. Place a temperature sensor and a heating rod inside the drain pipe. The temperature sensor is placed 10mm below the water surface, and the heating temperature is set to 0℃ to 5℃ to release the expansion pressure in time during the freezing process of the ice layer. Hang a weight on one end of a graduated nickel wire rope and place it in water for subsequent ice thickness measurement. The nickel wire rope has millimeter-level accuracy. Lift the weight to the bottom of the ice to read the ice thickness. During the freezing process, the temperature chain monitors the temperature changes of the ice layer in real time. The distance between adjacent measuring points is 50mm. The temperature data of each layer of ice is recorded to estimate the ice thickness and analyze the ice temperature distribution. One end of the cable-type displacement sensor is attached to the outside of the circular casing, and the other end is attached to the circular or square pier to measure the actual displacement of the circular or square pier relative to the circular casing. The cable-type displacement sensor and pressure sensor are connected to a data acquisition box, which is then connected to a computer for real-time readings. Before the test begins, the initial readings of the pressure sensor and cable-type displacement sensor are calibrated. Then, a jack is activated to apply a load to the straight plate support via a pressure pump. The force is then transmitted to the circular or square pier via the I-beam, causing the circular or square pier to move relative to the ice layer. Stop loading when the actual displacement of the circular or square pier relative to the circular casing reaches 50 mm, record the changing trend of the load-displacement curve, and measure the actual thickness of the ice layer with a caliper; After the test, the heating rod in the drain pipe is started to melt the ice layer, and the I-beam is restored to its original position through the tripod. The next test will be carried out when the thickness of the ice layer reaches the predetermined requirement.

9. The test method for the test device for studying the interaction between ice and structure in cold region reservoirs according to claim 8, characterized in that: The following steps are also included: During the test observation process, as the jack pushed, the load gradually increased, and relative displacement occurred between the ice layer and the circular or square piers, causing cracks in the ice surface. The displacement corresponding to the peak load of the circular piers was recorded, verifying that the ultimate bearing capacity increased significantly with increasing ice thickness. The peak load of the square piers occurred earlier than that of the circular piers and decreased faster. A freezing force model is constructed, that is, the freezing strength between the ice layer and the circular or square bridge pier is related to the surface roughness of the pier. The freezing force model is used to describe the freezing force when the ice layer interacts with the bridge pier. The mathematical expression of the freezing force model is: F f =A·τ f =A·(μ·s n +c) Among them: F f : Total freezing force (kN) A: Ice-pier contact area (m 2 ) τ f :Freezing strength (kPa) μ: Friction coefficient (related to the surface roughness of the bridge pier) σ n : Normal stress (kPa) c: Cohesion (kPa, related to ice thickness and temperature).

10. The test method for the test device for studying the interaction between ice and structure in cold region reservoirs according to claim 9, characterized in that: The following steps are also included: Obtain load-displacement curves and calculation results of the first ice load peak for circular and square piers under different pier cross-sections and different ice thickness conditions, and further obtain load-displacement curves and calculation results of the second ice load peak corresponding to the above curves and calculation results considering the freezing force model; For circular piers, when the ice thickness is 5 cm, 10 cm, and 15 cm, the difference between the second ice load peak value of the model considering freezing force and the first ice load peak value of the model not considering freezing force is 4.2%, -1.8%, and -3.8%, respectively. For square piers, when the ice thickness is 10 cm and 15 cm, the difference between the second ice load peak value and the first ice load peak value is -3.5% and -3.4%, respectively, and the difference is within 5%. Furthermore, the standard calculated value G of ice load for different pier cross-sections under different ice layer thicknesses, the model calculated value N without considering freezing force, and the model calculated value F with considering freezing force were introduced. Comparing the above data, the ratio N / G of the peak ice load calculated without considering freezing force to the standard calculated value fluctuated around 1. Meanwhile, the ratio F / N of the peak ice load calculated with freezing force to the calculated value without considering freezing force fluctuated within a certain range, with the circular cross-section fluctuating around 1.63 and the square cross-section fluctuating around 1.

49. To this end, the coefficient ξ is introduced to consider the influence of freezing force, and the following formula is established for correction: F=ξαDhσ c Where F is the static ice pressure of the bridge pier frozen in the ice layer; ξ is the correction factor considering the influence of the cross-section, which is 1.64 for circular cross-sections and 1.49 for square cross-sections; D is the width of the extrusion surface where the ice layer directly contacts the bridge pier and produces an extrusion effect; h is the ice thickness; σ c is the uniaxial compressive strength of ice; α is the shape coefficient of the pier front edge.

Images