A slope model test device and method under thermal-mechanical coupling in alpine regions

Abstract

The present invention belongs to the field of slope engineering technology, specifically relating to a device and method for testing slope models under thermal coupling in high-altitude cold regions. The device comprises a pipe pile, a cover plate, a lateral loading system, a freezing system, a heat exchange system, and a monitoring system. The lateral loading system comprises a pressure plate and a drive mechanism connected in sequence. Rotating the pressure plate changes the loading angle, enabling simulation of complex slope lateral constraints. The freezing system simulates the soil temperature field in high-altitude cold regions. The heat exchange system comprises a U-shaped heat exchange tube and a thermal response instrument. The U-shaped heat exchange tube heats the pipe pile and the surrounding soil, and the reflux coolant then enters the thermal response instrument for reuse. The monitoring system comprises a temperature sensor, a strain gauge, an earth pressure gauge, and a displacement meter. The present invention addresses the existing problems of being unable to analyze the stability of slope soil under lateral uneven loads and geothermal effects, and unable to conduct feasibility studies on the use of ground-source heat pump technology in slope snow and ice melting.

Description

Technical Field

[0001] The invention belongs to the technical field of slope engineering, and in particular relates to a slope model test device and method under thermal-mechanical coupling in alpine regions. Background Art

[0002] In high-altitude cold regions, slopes subjected to repeated freezing and thawing in snowy weather can easily lead to loose soil and damage. The water formed by the melting of ice and snow seeps into the soil, causing the soil's strength to decrease and its anti-slip ability to decrease. Under the action of load, the soil is prone to local slippage or even overall damage. Ground-source heat pump technology exchanges heat with the surrounding soil and even the pile foundation through the fluid in the heat exchange tube, which can heat the upper structure, help melt the snow water on the ground, and prevent the soil from freezing.

[0003] At present, in model test research on slopes, most devices are unable to realize the combined effect study of geothermal and mechanical responses. The research on slopes mainly focuses on the effects of rainfall and vertical loads, and rarely considers the influence of lateral loads and geothermal heat. It is impossible to effectively study the stability of slopes in high-altitude and cold areas. Summary of the Invention

[0004] The present invention provides a slope model test device and method under the action of thermal coupling in high-altitude cold areas, so as to solve the problems that the existing technology cannot realize the stability analysis of slope soil under lateral uneven load and geothermal effect, and cannot conduct feasibility research on ground source heat pump technology in slope snow and ice melting.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a slope model test device under thermal coupling in alpine areas, the test device comprising a model box with an open top, pipe piles, a cover plate, a side loading system, a freezing system, a heat exchange system and a monitoring system, wherein:

[0006] The model box is filled with slope soil, and the pipe piles are buried in the slope soil;

[0007] The cover plate is arranged on a side wall inside the model box, and the lower end of the cover plate is hinged to the side wall of the model box, and the angle between the cover plate and the model box corresponds to the compression angle of the simulated slope side;

[0008] The lateral loading system includes a pressure plate and a driving mechanism connected in sequence. The pressure plate is arranged between the cover plate and the side wall of the model box. The driving mechanism is arranged on the side of the pressure plate facing away from the cover plate. The driving mechanism is hinged to the pressure plate and provides a driving force to press the pressure plate toward the cover plate. The simulation of the lateral constraint of the slope is achieved through the cooperation of the driving mechanism, the pressure plate and the cover plate.

[0009] The freezing system includes a freezing pipe and a freezing device. The freezing pipe is pre-buried in the slope soil filled in the model box. The freezing pipe is connected to the freezing device. The freezing pipe and the freezing device cooperate to cool the slope soil filled in the model box to simulate the soil temperature field in the alpine region.

[0010] The heat exchange system includes a U-shaped heat exchange tube and a thermal response instrument. The U-shaped heat exchange tube is buried inside the pipe pile and distributed along the depth of the pipe pile. The thermal response instrument is arranged outside the model box and connected to the U-shaped heat exchange tube. The heat flow output by the heat exchange system heats the pipe pile and the surrounding soil through the U-shaped heat exchange tube, and then the reflux cooling liquid enters the thermal response instrument for repeated use.

[0011] The monitoring system includes a plurality of temperature-sensing sheets arranged on the inner wall of the pipe pile, a plurality of strain gauges arranged on the outer wall of the pipe pile in contact with the slope soil, a plurality of earth pressure gauges arranged in the slope soil, a plurality of displacement gauges arranged on the slope surface simulated by the slope soil, a temperature collector connected to the plurality of temperature-sensing sheets, a strain collector connected to the plurality of strain gauges, a pressure collector connected to the plurality of earth pressure gauges, and a displacement collector connected to the plurality of displacement gauges;

[0012] The test device simulates the slope environment under the thermal coupling of high-altitude cold areas through the lateral loading system, the freezing system and the heat exchange system, and then studies the stability of the slope in the high-altitude cold areas through the test data of temperature, deformation, pressure and displacement collected by the monitoring system.

[0013] As a further preferred embodiment of the present invention, the driving mechanism includes a piston, a first articulated support, a cylinder, a hydraulic pipe, a hydraulic device and a hydraulic gauge connected in sequence, the piston is arranged on the side wall of the model box connected to the cover plate, the first articulated support connects the piston to the pressure plate, the cylinder is connected to the piston, the hydraulic pipe connects the cylinder to the hydraulic device, and the hydraulic device is provided with the hydraulic gauge.

[0014] As a further preferred embodiment of the present invention, the freezing equipment is provided with a brine tank, a water pump and a condenser pipe which are connected in sequence.

[0015] As a further preferred embodiment of the present invention, the freezing pipe includes a freezing pipe body, a first water baffle, a second water baffle, a water inlet steel pipe and a water outlet steel pipe, wherein:

[0016] The freezing tube body is a tubular structure with two ends open;

[0017] The first water baffle is arranged at the end of the freezing pipe, and the second water baffle is arranged inside the freezing pipe near the other end of the freezing pipe;

[0018] One end of the water inlet steel pipe passes through the second water baffle and extends into the interior of the freezing pipe, and the other end is connected to the condensing pipe in the freezing equipment;

[0019] One end of the water outlet steel pipe is arranged on the second water baffle and communicates with the inside of the freezing pipe, and the other end is connected to the brine tank in the freezing equipment.

[0020] As a further preferred embodiment of the present invention, the present invention further comprises a pulley receiving plate, at least two receiving cavities, at least two partitions, at least two pulley supports, at least two pulleys, at least four ear plates and at least two limit plates, wherein:

[0021] The pulley storage plate is arranged below the bottom plate of the model box;

[0022] The storage cavity is provided inside the pulley storage plate;

[0023] The partition is arranged on the top of the pulley storage plate along the depth direction of the storage cavity, and the partition is located in the storage cavity. The depth of the partition is shallower than the depth of the storage cavity, and two opposite grooves are opened along the depth direction of the partition;

[0024] The pulley support comprises a top plate and a connecting piece, wherein the top plate is located in the receiving cavity and below the partition plate and is coaxial with the partition plate, and the connecting piece connects the pulley to the top plate;

[0025] Two opposite ear plates are provided on the outer edge of the top plate, and the top plate can be rotated to adjust the alignment of the two ear plates with the two grooves of the partition plate, so that the ear plates can move along the length direction of the groove in the space between the receiving cavity wall and the partition plate;

[0026] In order to always limit the top plate of the pulley support within the storage cavity, the limiting plate is formed at the portion extending toward the partition plate 39 from the bottom edge of the storage cavity.

[0027] As a further preferred embodiment of the present invention, the cross-sections of the storage cavity, the partition and the top plate are all circular.

[0028] A test method using a slope model test device under thermal-mechanical coupling in alpine regions is also provided, comprising the following steps:

[0029] Step S1: Determine the slope model parameters to be simulated:

[0030] Step S1-1, measuring the on-site parameters, measuring the on-site slope, and obtaining the height h1 and slope i1 of the on-site slope;

[0031] Step S1-2: According to the on-site parameters measured in step S1-1, the height of the slope model is determined to be h2, where h2:h1=1:100, and the slope of the slope model is determined to be i2, where i2=i1;

[0032] Step S2: Set test parameters:

[0033] Set the test lateral pressure application angle, that is, the angle between the cover plate and the side wall of the model box, to α 设 , set the temperature of the inner wall of the pile and the surrounding soil as T 设 , set the lateral pressure load to G 设 ;

[0034] Step S3: constructing the slope model:

[0035] Step S3-1, adjust the angle α between the cover plate and the side wall of the model box to the set value α 设 , and then adjusting the pressure plate and the cover plate to overlap;

[0036] Step S3-2: Fill the slope soil layer by layer, determining the number of layers of the layered filled slope soil to be n; fill the first layer of slope soil to a thickness of 10 cm, and pre-embed a plurality of the earth pressure gauges and the strain gauges in the first layer of slope soil; fill the second layer of slope soil to a thickness of 10 cm, and pre-embed a plurality of the earth pressure gauges and the strain gauges in the second layer of slope soil... Fill the last layer of slope soil to a thickness of [h2 - 10 × (n - 1)] cm, and pre-embed a plurality of the earth pressure gauges and the strain gauges in the last layer of slope soil. When filling the last layer of slope soil, pre-embed the freezing pipes;

[0037] When pre-buried, the soil pressure gauge needs to be connected to the pressure collector via a connecting line, and when pre-buried, the strain gauge needs to be connected to the strain collector via a connecting line;

[0038] Step S3-3: The side of the slope soil facing away from the cover plate is the slope surface, and a plurality of displacement meters are arranged on the slope surface;

[0039] Step S4: Install the U-shaped heat exchange tube:

[0040] The U-shaped heat exchange tube is placed inside the pipe pile and distributed along the depth, a temperature sensor is tied at the water inlet and outlet ends of the U-shaped heat exchange tube, and the U-shaped heat exchange tube is connected to the thermal response instrument;

[0041] Step S5: Adjust the thermal response instrument:

[0042] Turn on the thermal response instrument, which delivers heated water to the U-shaped heat exchange tube through the insulation hose to circulate and heat the soil. The instrument also monitors the temperature changes on the temperature collector in real time, monitoring the temperature changes of the inner wall of the pile and the surrounding soil. When the temperature rises to T 设 When the temperature reaches 0.05°C, the thermal response instrument is adjusted to perform constant temperature heating;

[0043] Step S6: Perform lateral load:

[0044] When the soil temperature rises to the test set value T 设 When the driving mechanism is in operation, the bearing plate is loaded in stages to achieve lateral non-uniform loading of the soil;

[0045] Step S7: Analyze the stability of the high-altitude cold region under the effect of thermal coupling:

[0046] By observing the data collected by the temperature collector, strain collector, pressure collector and displacement collector during the graded loading in step S6, the stability of the slope soil under lateral uneven load and geothermal action is analyzed, and the feasibility of ground source heat pump technology in slope snow and ice melting is studied.

[0047] As a further preferred embodiment of the present invention, after each level of loading is completed in step S6, the pressure must be kept constant, and the pressure collector, strain collector, and displacement collector are observed. After the changes are stable, they are recorded and the next level of loading is performed. This step is repeated until the set value G is reached. 设 ;

[0048] Before each loading, the temperature collector reading must be read to ensure that the soil temperature remains constant. If the reading changes, adjust it to the set value T through the thermal response instrument. 设 .

[0049] Through the above technical solution, compared with the existing technology, the present invention has the following beneficial effects:

[0050] The present invention can carry out slope model tests under the combined action of lateral load and ground source heat, and observe the deformation of slope soil under the action of heat.

[0051] The present invention takes into account the influence of low temperature in alpine areas and can simulate the temperature field of slope soil in alpine areas.

[0052] The present invention can adjust the size of the lateral load as well as the ground source heat temperature and burial depth, thereby performing stability analysis of the slope under thermal action.

[0053] The pulley provided at the bottom of the model box of the present invention can be retracted into the pulley receiving plate to prevent the model box from being damaged due to local pressure on the bottom plate during the test pressurization process.

[0054] The cover plate of the side wall of the model box of the present invention can adjust the angle to realize loading of the slope in different directions.

[0055] The heat exchange system of the present invention can circulate the water in the water tank for heating, and can adjust the heating temperature and liquid flow rate, and can also monitor the temperature of the inlet and outlet water in real time, thereby improving the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The present invention will be further described below with reference to the accompanying drawings and examples.

[0057] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0058] Figure 2 This is a schematic diagram of the freezing pipe structure of the present invention;

[0059] Figure 3 This is a cross-sectional view of the pipe pile structure of the present invention;

[0060] Figure 4 It is a schematic diagram of the retractable pulley structure of the present invention.

[0061] In the figure: 1- model box, 2- slope soil, 3- cover plate, 4- pressure plate, 5- first hinged support, 6- second hinged support, 7- oil cylinder, 8- piston, 9- hydraulic pipe, 10- hydraulic gauge, 11- hydraulic equipment, 12- pulley receiving plate, 13- pulley support, 14- pulley, 15- bottom plate, 16- top plate, 17- connecting piece, 18- strain gauge, 19- temperature sensor, 20- soil pressure gauge, 21- displacement meter, 22- pipe pile, 23- U-shaped heat exchange tube, 24- temperature Sensor, 25-freezing pipe, 26-insulating hose, 27-freezing equipment, 28-brine tank, 29-water pump, 30-condenser, 31-thermal response instrument, 32-first water baffle, 33-second water baffle, 34-water inlet steel pipe, 35-water outlet steel pipe, 36-binding steel bars, 37-freezing pipe body, 38-storage cavity, 39-partition, 40-pressure collector, 41-temperature collector, 42-strain collector, 43-displacement collector, 44-ear plate, 45-limiting plate. DETAILED DESCRIPTION

[0062] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner, and thus only show components relevant to the present invention.

[0063] In the description of the present invention, it should be understood that the terms "left side," "right side," "upper," "lower," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Terms such as "first" and "second" do not indicate the importance of components and therefore should not be construed as limitations on the present invention. The specific dimensions used in this embodiment are intended only to illustrate the technical solution and do not limit the scope of protection of the present invention. Example

[0064] This embodiment provides a preferred embodiment. Figure 1 As shown, a slope model test device under thermal-mechanical coupling in alpine regions includes a model box 1, pipe piles, a cover plate 3, a side loading system, a freezing system, a heat exchange system, and a monitoring system, wherein:

[0065] The model box 1 has an open top and is mainly composed of a metal plate, one side of which is a transparent thickened glass plate. The model box 1 is filled with slope soil 2, which is preferably composed of saturated sand, clay or gravel soil.

[0066] During the test, the pipe piles 22 are buried in the slope soil 2 . Before burying, the pipe piles 22 can be fixed inside the model box 1 .

[0067] The above-mentioned cover plate 3 is arranged on a side wall inside the model box 1, and the lower end of the cover plate 3 is hinged to the side wall of the model box 1. The angle between the cover plate 3 and the model box 1 corresponds to the compression angle of the simulated slope side. Specifically, the cover plate 3 is arranged on a metal side wall close to the transparent thickened glass plate; the lower end of the cover plate 3 is connected to the middle section of the lower half of the side wall of the model box 1 through a second hinged support 6, ensuring that part of the length of the cover plate 3 must be outside the slope soil 2, so as to facilitate the adjustment of the angle between the cover plate 3 and the side wall of the model box 1, that is, the adjustment of the simulated slope. This embodiment sets different compression angles of the slope side by adjusting the angle between the cover plate 3 and the side of the model box 1.

[0068] The above-mentioned lateral loading system includes a pressure plate 4 and a driving mechanism connected in sequence. The pressure plate 4 is arranged between the cover plate 3 and the side wall of the model box 1. The driving mechanism is arranged on the side of the pressure plate 4 away from the cover plate 3. The driving mechanism is hinged to the pressure plate 4, and the driving mechanism provides a driving force to press the pressure plate 4 toward the cover plate 3. The simulation of the lateral constraint of the slope is achieved through the cooperation of the driving mechanism, the pressure plate 4 and the cover plate 3.

[0069] Specifically, the above-mentioned driving mechanism includes a piston 8, a first articulated support 5, an oil cylinder 7, a hydraulic pipe 9, a hydraulic device 11 and a hydraulic gauge 10 connected in sequence. The piston 8 is arranged on the side wall of the model box 1 connected to the cover plate 3. The first articulated support 5 connects the piston 8 to the pressure plate 4, the oil cylinder 7 is connected to the piston 8, the hydraulic pipe 9 connects the oil cylinder 7 to the hydraulic device 11, and the hydraulic device 11 is provided with the hydraulic gauge 10.

[0070] The freezing system includes a freezing pipe 25 and a freezing device 27. The freezing pipe 25 is pre-buried in the slope soil 2 filled in the model box 1 and connected to the freezing device 27. Through the freezing pipe 25 and the freezing device 27, the slope soil filled in the model box 1 is cooled, simulating the soil temperature field in high-altitude cold regions. The freezing device 27 is equipped with a brine tank 28, a water pump 29, and a condenser 30 connected in sequence. After the water in the brine tank 28 is cooled by the condenser 30, it is transported to the freezing pipe 25 through the water inlet steel pipe 34 to freeze and cool the soil.

[0071] The freezing pipe 25 includes a freezing pipe 25 body, a first water baffle 32, a second water baffle 33, a water inlet steel pipe 34 and a water outlet steel pipe 35. The freezing pipe 25 body is a tubular structure with both ends open; the first water baffle 32 is arranged at the end of the freezing pipe 25, and the second water baffle 33 is arranged inside the freezing pipe 25 near the other end of the freezing pipe 25; one end of the water inlet steel pipe 34 passes through the second water baffle 33 and extends into the freezing pipe 25, and the other end is connected to the condenser pipe 30 in the freezing device 27; one end of the water outlet steel pipe 35 is arranged on the second water baffle 33 and communicates with the inside of the freezing pipe 25, and the other end is connected to the brine tank 28 in the freezing device 27.

[0072] The heat exchange system includes a U-shaped heat exchange tube 23 and a thermal response instrument 31. The U-shaped heat exchange tube 23 is buried within the pipe pile 22 and distributed along the depth of the pipe pile 22. The thermal response instrument 31 is located outside the model box 1 and connected to the U-shaped heat exchange tube 23. A temperature sensor 24 is installed at the end of the U-shaped heat exchange tube 23 and is connected to the thermal response instrument 31 via an insulating hose 26. The heat flow output by the heat exchange system passes through the U-shaped heat exchange tube 23 to heat the pipe pile 22 and the surrounding soil. The reflux cooling liquid then enters the thermal response instrument 31 for reuse.

[0073] The monitoring system includes several temperature sensors 19 installed on the inner wall of the pipe pile 22 and arranged along the depth of the pipe pile 22 through binding steel bars 36; several strain gauges 18 installed on the outer wall of the pipe pile 22 in contact with the slope soil 2; several earth pressure gauges 20 installed within the slope soil 2; several displacement gauges 21 installed on the slope surface simulated by the slope soil 2; temperature collectors 41 connected to the temperature sensors 19; strain collectors 42 connected to the strain gauges 18; pressure collectors 40 connected to the earth pressure gauges 20; and displacement collectors 43 connected to the displacement gauges 21. The displacement gauges 21 can be replaced by dial indicators.

[0074] This embodiment simulates the slope environment under the thermal coupling of high-altitude cold areas through the lateral loading system, the freezing system and the heat exchange system, and then studies the stability of the slope in high-altitude cold areas through the test data of temperature, deformation, pressure and displacement collected by the monitoring system.

[0075] During the test, it is necessary to ensure that the model box 1 remains stationary and does not move, that is, to prevent the bottom plate 15 from being locally compressed during the test pressurization process, thereby preventing the model box 1 from being damaged. This embodiment includes a pulley 14 receiving plate 12, at least two receiving cavities 38, at least two partitions 39, at least two pulley supports 13, at least two pulleys 14, at least four lugs 44, and at least two limit plates 45.

[0076] The pulley 14 receiving plate 12 is disposed below the bottom plate 15 of the mold box 1; the receiving cavity 38 is provided within the pulley 14 receiving plate 12. The partition 39 is provided at the top of the pulley 14 receiving plate 12 along the depth direction of the receiving cavity 38, and the partition 39 is located within the receiving cavity 38. The depth of the partition 39 is shallower than the depth of the receiving cavity 38, and two opposing grooves are provided along the depth direction of the partition 39. The pulley support 13 includes a top plate 16 and a connecting member 17. The top plate 16 is located within the receiving cavity 38 and below the partition 39, coaxial with the partition 39. The connecting member 17 connects the pulley 14 to the top plate 16. Two opposite ear plates 44 are provided on the outer edge of the top plate 16. The top plate 16 can be rotated to adjust the two ear plates 44 to align with the two grooves of the partition 39, so that the ear plates 44 in the space between the wall of the storage cavity 38 and the partition 39 can move along the length direction of the groove.

[0077] In order to always limit the top plate 16 of the pulley support 13 within the receiving cavity 38, the limit plate 45 is formed at the bottom edge of the receiving cavity 38 extending toward the partition 39. Preferably, the receiving cavity 38, the partition 39 and the top plate 16 are all circular in cross section.

[0078] This embodiment also provides a test method using a slope model test device under thermal-mechanical coupling in alpine regions, specifically comprising the following steps:

[0079] Step S1: Determine the slope model parameters to be simulated:

[0080] Step S1-1, measuring the on-site parameters, measuring the on-site slope, and obtaining the height h1 and slope i1 of the on-site slope;

[0081] Step S1-2: According to the on-site parameters measured in step S1-1, the height of the slope model is determined to be h2, where h2:h1=1:100, and the slope of the slope model is determined to be i2, where i2=i1.

[0082] Step S2: Set test parameters:

[0083] The test lateral pressure angle, i.e. the angle between the cover plate 3 and the side wall of the model box 1, is set to α. 设 , set the temperature of the inner wall of the pipe pile 22 and the surrounding soil to T 设 , set the lateral pressure load to G 设 .

[0084] Step S3: constructing the slope model:

[0085] Step S3-1, adjust the angle α between the cover plate 3 and the side wall of the model box 1 to the set value α 设 , and then adjust the pressure plate 4 and the cover plate 3 to overlap;

[0086] Step S3-2: Fill the slope soil 2 in layers. Determine the number of layers of slope soil to be filled in layers as n. Fill the first layer of slope soil 2 to a thickness of 10 cm, and pre-embed a plurality of the soil pressure gauges 20 and strain gauges 18 within the first layer of slope soil 2. Fill the second layer of slope soil 2 to a thickness of 10 cm, and pre-embed a plurality of the soil pressure gauges 20 and strain gauges 18 within the second layer of slope soil 2. Fill the last layer of slope soil 2 to a thickness of [h2 - 10 × (n - 1)] cm, and pre-embed a plurality of the soil pressure gauges 20 and strain gauges 18 within the last layer of slope soil 2. When filling the last layer of slope soil 2, pre-embed the freezing pipes 25. When pre-embedding the soil pressure gauges 20, they must be connected to the pressure collector 40 via a connecting wire. When pre-embedding the strain gauges 18, they must also be connected to the strain collector 42 via a connecting wire.

[0087] Specifically, the soil pressure gauge 20 and strain gauge 18 are arranged at the junction of each layer, with two to six arranged on each layer, located on both sides of the pipe pile 22 respectively. The temperature sensing piece 19 is arranged on the inner wall of the pipe pile 22, with one to three arranged on each layer along the depth direction and four arranged horizontally at the top surface of the slope. The displacement meter 21 is arranged on the slope surface, with one to three arranged at the junction of each layer.

[0088] Step S3-3: The side of the slope soil 2 facing away from the cover plate 3 is a slope surface, and a plurality of displacement meters 21 are arranged on the slope surface.

[0089] Before proceeding to step S3 to construct the slope model, the test device is assembled and then pushed to the test site. The pulley support 13 is then rotated to rotate the top plate 16 within the receiving chamber 38 until the two ear plates 44 correspond to the two grooves on the partition plate 39. Then, due to the action of gravity, the test device moves downward, that is, the two ear plates 44 on the outer edges of the top plate 16 move upward along the length of the two grooves until the receiving plate 12 of the pulley 14 touches the ground. At this time, the pulley 14 is completely stored in the receiving chamber 38.

[0090] Step S4: Install the U-shaped heat exchange tube 23:

[0091] The U-shaped heat exchange tube 23 is placed inside the pipe pile 22 and distributed along the depth. The temperature sensor 24 is tied at the water inlet and outlet ends of the U-shaped heat exchange tube 23, and the U-shaped heat exchange tube 23 is connected to the thermal response instrument 31 through the insulation hose 26.

[0092] Step S5: Adjust the thermal response instrument 31:

[0093] The thermal response instrument 31 is turned on. The thermal response instrument 31 transmits heated water to the U-shaped heat exchange tube 23 through the thermal insulation hose 26 to heat the soil in a cycle. The temperature change on the temperature collector 41 is monitored in real time to monitor the temperature change of the inner wall of the pile 22 and the surrounding soil. When the temperature rises to T 设 When the temperature is 0, the thermal response device 31 is adjusted to perform constant temperature heating.

[0094] Step S6: Perform lateral load:

[0095] When the soil temperature rises to the test set value T 设 When the driving mechanism is in operation, the bearing plate 4 is loaded in stages to achieve lateral non-uniform loading of the soil.

[0096] Specifically, after each level of loading is completed, the pressure must be kept constant, and the pressure collector 40, strain collector 42, and displacement collector 43 are observed. After the changes are stable, they are recorded and the next level of loading is carried out. This step is repeated until the set value G is reached. 设Before each loading, the reading of the temperature collector 41 must be read to ensure that the soil temperature remains constant. If the reading changes, the thermal response instrument 31 is used to adjust it to the set value T 设 .

[0097] After step S6 loading is completed, the slope soil 2 is first unloaded through the hydraulic equipment 11. During the unloading process, the changes in the readings of the soil pressure gauge 20, the strain gauge 18 and the displacement meter 21 are constantly observed, and the deformation during the unloading process is recorded. Finally, the thermal response instrument 31 is adjusted to stop the cyclic heating.

[0098] Step S7: Analyze the stability of the high-altitude cold region under the effect of thermal coupling:

[0099] By observing the data collected by the temperature collector 41, strain collector 42, pressure collector 40 and displacement collector 43 during the graded loading in step S6, the stability of the slope soil 2 under lateral uneven load and geothermal action is analyzed, and the feasibility of ground source heat pump technology in slope snow and ice melting is studied.

[0100] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such, will not be interpreted in an idealized or overly formal sense.

[0101] The meaning of "and / or" in this application means that both situations where each exists alone or both exist at the same time are included.

[0102] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0103] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A slope model test device under thermal-mechanical coupling in alpine regions, comprising a model box with an open top, characterized in that: The test device includes pipe piles, cover plates, side loading system, freezing system, heat exchange system and monitoring system, wherein: The model box is filled with slope soil, and the pipe piles are buried in the slope soil; The cover plate is arranged on a side wall inside the model box, and the lower end of the cover plate is hinged to the side wall of the model box, and the angle between the cover plate and the model box corresponds to the compression angle of the simulated slope side; The lateral loading system includes a pressure plate and a driving mechanism connected in sequence. The pressure plate is arranged between the cover plate and the side wall of the model box. The driving mechanism is arranged on the side of the pressure plate facing away from the cover plate. The driving mechanism is hinged to the pressure plate and provides a driving force to press the pressure plate toward the cover plate. The simulation of the lateral constraint of the slope is achieved through the cooperation of the driving mechanism, the pressure plate and the cover plate. The freezing system includes a freezing pipe and a freezing device. The freezing pipe is pre-buried in the slope soil filled in the model box. The freezing pipe is connected to the freezing device. The freezing pipe and the freezing device cooperate to cool the slope soil filled in the model box to simulate the soil temperature field in the alpine region. The heat exchange system includes a U-shaped heat exchange tube and a thermal response instrument. The U-shaped heat exchange tube is buried inside the pipe pile and distributed along the depth of the pipe pile. The thermal response instrument is arranged outside the model box and connected to the U-shaped heat exchange tube. The heat flow output by the heat exchange system heats the pipe pile and the surrounding soil through the U-shaped heat exchange tube, and then the reflux cooling liquid enters the thermal response instrument for repeated use. The monitoring system includes a plurality of temperature-sensing sheets arranged on the inner wall of the pipe pile, a plurality of strain gauges arranged on the outer wall of the pipe pile in contact with the slope soil, a plurality of earth pressure gauges arranged in the slope soil, a plurality of displacement gauges arranged on the slope surface simulated by the slope soil, a temperature collector connected to the plurality of temperature-sensing sheets, a strain collector connected to the plurality of strain gauges, a pressure collector connected to the plurality of earth pressure gauges, and a displacement collector connected to the plurality of displacement gauges; The test device simulates the slope environment under the thermal coupling of high-altitude cold areas through the lateral loading system, the freezing system and the heat exchange system, and then studies the stability of the slope in the high-altitude cold areas through the test data of temperature, deformation, pressure and displacement collected by the monitoring system.

2. The slope model test device under thermal-mechanical coupling in alpine regions according to claim 1 is characterized by: The driving mechanism includes a piston, a first articulated support, a cylinder, a hydraulic pipe, a hydraulic device and a hydraulic gauge connected in sequence. The piston is arranged on the side wall of the model box connected to the cover plate. The first articulated support connects the piston to the pressure plate, the cylinder is connected to the piston, the hydraulic pipe connects the cylinder to the hydraulic device, and the hydraulic device is provided with the hydraulic gauge.

3. The slope model test device under thermal-mechanical coupling in alpine regions according to claim 1 is characterized by: The freezing device is provided with a brine tank, a water pump and a condenser pipe which are connected in sequence.

4. The slope model test device under thermal-mechanical coupling in alpine regions according to claim 3 is characterized by: The freezing pipe includes a freezing pipe body, a first water baffle, a second water baffle, a water inlet steel pipe and a water outlet steel pipe, wherein: The freezing tube body is a tubular structure with two ends open; The first water baffle is arranged at the end of the freezing pipe, and the second water baffle is arranged inside the freezing pipe near the other end of the freezing pipe; One end of the water inlet steel pipe passes through the second water baffle and extends into the interior of the freezing pipe, and the other end is connected to the condensing pipe in the freezing equipment; One end of the water outlet steel pipe is arranged on the second water baffle and communicates with the inside of the freezing pipe, and the other end is connected to the brine tank in the freezing equipment.

5. The slope model test device under thermal-mechanical coupling in alpine regions according to claim 1 is characterized by: It also includes a pulley receiving plate, at least two receiving cavities, at least two partitions, at least two pulley supports, at least two pulleys, at least four ear plates and at least two limit plates, wherein: The pulley storage plate is arranged below the bottom plate of the model box; The storage cavity is provided inside the pulley storage plate; The partition is arranged on the top of the pulley storage plate along the depth direction of the storage cavity, and the partition is located in the storage cavity. The depth of the partition is shallower than the depth of the storage cavity, and two opposite grooves are opened along the depth direction of the partition; The pulley support comprises a top plate and a connecting piece, wherein the top plate is located in the receiving cavity and below the partition plate and is coaxial with the partition plate, and the connecting piece connects the pulley to the top plate; Two opposite ear plates are provided on the outer edge of the top plate, and the top plate can be rotated to adjust the alignment of the two ear plates with the two grooves of the partition plate, so that the ear plates in the space between the receiving cavity wall and the partition plate can move along the length direction of the groove; In order to always limit the top plate of the pulley support within the receiving cavity, the limiting plate is formed at a portion extending toward the partition plate from the bottom edge of the receiving cavity.

6. The slope model test device under thermal-mechanical coupling in alpine regions according to claim 5, characterized in that: The cross sections of the receiving cavity, the partition and the top plate are all circular.

7. A test method using the slope model test device under thermal-mechanical coupling in alpine regions according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1: Determine the slope model parameters to be simulated: Step S1-1, measuring the on-site parameters, measuring the on-site slope, and obtaining the height h1 and slope i1 of the on-site slope; Step S1-2: According to the on-site parameters measured in step S1-1, the height of the slope model is determined to be h2, where h2:h1=1:100, and the slope of the slope model is determined to be i2, where i2=i1; Step S2: Set test parameters: Set the test lateral pressure application angle, that is, the angle between the cover plate and the side wall of the model box, to α 设 , set the temperature of the inner wall of the pile and the surrounding soil as T 设 , set the lateral pressure load to G 设 ; Step S3: constructing the slope model: Step S3-1, adjust the angle α between the cover plate and the side wall of the model box to the set value α 设 , and then adjusting the pressure plate and the cover plate to overlap; Step S3-2: Fill the slope soil layer by layer, determining the number of layers of the layered filled slope soil to be n; fill the first layer of slope soil to a thickness of 10 cm, and pre-embed a plurality of the earth pressure gauges and the strain gauges in the first layer of slope soil; fill the second layer of slope soil to a thickness of 10 cm, and pre-embed a plurality of the earth pressure gauges and the strain gauges in the second layer of slope soil... Fill the last layer of slope soil to a thickness of [h2 - 10 × (n - 1)] cm, and pre-embed a plurality of the earth pressure gauges and the strain gauges in the last layer of slope soil. When filling the last layer of slope soil, pre-embed the freezing pipes; When pre-buried, the soil pressure gauge needs to be connected to the pressure collector via a connecting line, and when pre-buried, the strain gauge needs to be connected to the strain collector via a connecting line; Step S3-3: The side of the slope soil facing away from the cover plate is the slope surface, and a plurality of displacement meters are arranged on the slope surface; Step S4: Install the U-shaped heat exchange tube: The U-shaped heat exchange tube is placed inside the pipe pile and distributed along the depth, a temperature sensor is tied at the water inlet and outlet ends of the U-shaped heat exchange tube, and the U-shaped heat exchange tube is connected to the thermal response instrument; Step S5: Adjust the thermal response instrument: Turn on the thermal response instrument, which delivers heated water to the U-shaped heat exchange tube through the insulation hose to circulate and heat the soil. The instrument also monitors the temperature changes on the temperature collector in real time, monitoring the temperature changes of the inner wall of the pile and the surrounding soil. When the temperature rises to T 设 When the temperature reaches 0.05°C, the thermal response instrument is adjusted to perform constant temperature heating; Step S6: Perform lateral load: When the soil temperature rises to the test set value T 设 When the driving mechanism is in operation, the bearing plate is loaded in stages to achieve lateral non-uniform loading of the soil; Step S7: Analyze the stability of the high-altitude cold region under the effect of thermal coupling: By observing the data collected by the temperature collector, strain collector, pressure collector and displacement collector during the graded loading in step S6, the stability of the slope soil under lateral uneven load and geothermal action is analyzed, and the feasibility of ground source heat pump technology in slope snow and ice melting is studied.

8. The test method according to claim 7, wherein: After each level of loading in step S6 is completed, the pressure must be kept constant, and the pressure collector, strain collector, and displacement collector are observed. After the changes are stable, record them and proceed to the next level of loading. Repeat this step until the set value G is reached. 设 ; Before each loading, the temperature collector reading must be read to ensure that the soil temperature remains constant. If the reading changes, adjust it to the set value T through the thermal response instrument. 设 .

Images