CN116429585A

CN116429585A - Device and method for detecting grouting performance of highway subgrade in severe cold region

Info

Publication number: CN116429585A
Application number: CN202211630777.7A
Authority: CN
Inventors: 高峰; 张军辉; 曾宪璋; 陈志德
Original assignee: Changsha University of Science and Technology
Current assignee: Changsha University of Science and Technology
Priority date: 2022-12-19
Filing date: 2022-12-19
Publication date: 2023-07-14

Abstract

The utility model provides a device and a method for detecting grouting performance of highway subgrade in severe cold areas. The cold bath pipe is arranged in the side wall interlayer space of the model box, antifreeze is filled outside the cold bath pipe, the cold bath pipe is spirally wound in the side wall interlayer space, and heat preservation cotton is sleeved outside the side wall and the box bottom of the model box. The utility model is suitable for testing grouting performance of highway subgrade in severe cold areas, deeply researches grouting diffusion characteristics under low-temperature conditions, establishes an evaluation system of grouting treatment effect of highway in severe cold areas, forms an optimal grouting technical scheme with high highway construction speed, low cost and good treatment effect, and has important theoretical significance and engineering value for scientifically knowing grouting rules of highway subgrade in cold areas, guiding highway disease control work and improving construction theory and maintenance technical level of highway subgrade structures in China.

Description

Device and method for detecting grouting performance of highway subgrade in severe cold region

Technical Field

The utility model belongs to the field of instrument and equipment development, and particularly relates to a device and a method for detecting grouting performance of a highway subgrade in a severe cold region.

Background

Road construction and maintenance are key foundations for promoting traffic development. Under the long-term freezing and thawing cycle, dry-wet alternation and traffic load coupling effect, frost heaving, thawing, sinking and slurry-forming diseases commonly occur on various highway lines in severe cold areas after 5-10 years of operation, thereby causing the crack of roadbed structures and the deterioration of road smoothness, bringing serious challenges to the safety and comfort of highway operation, and greatly increasing the maintenance cost of the lines. Therefore, research on prevention and control technology for treating and controlling the frost heaving, thawing and sinking and slurry-turning mud-like diseases of highway subgrades in severe cold areas is unprecedented.

As a main treatment mode of frozen swelling, thawing and sinking of highway subgrade and mud-pumping disease, the grouting technology and the matched construction technology are commonly applied at home and abroad at present. The traditional grouting has the advantages of convenient operation, economy, high efficiency, difficult influence of driving conditions and weather in the construction treatment process and the like. However, in severe cold areas such as northern China and Qinghai-Tibet plateau, the surface temperature is low in winter, and the distribution of frozen soil and seasonal frozen soil is wide for many years, so that the highway foundation is very sensitive to the external environment and climate change. Engineering practice shows that when the road subgrade in severe cold areas is subjected to disease treatment by grouting, the repairing effect can play a good role in the early stage of grouting, but the long-term effect is not ideal. The fundamental reason is that the grouting performance and evolution rule of the highway subgrade in severe cold areas are not known clearly, so that great blindness is brought to the design and construction of grouting, and the selection of grouting control parameters mainly depends on practical experience and the like. With the large-scale development of the construction of traffic infrastructures in northern China and Qinghai-Tibet plateau, complex geological conditions, climates and construction environments provide higher requirements for highway grouting technology, and development of basic science and application research related to tracing and evaluating grouting performance and treatment effect of highway subgrade in severe cold areas is urgently needed.

At present, the system and the method for deeply researching the low-ground temperature condition in the severe cold region or the grouting design theory and the detection evaluation method in the frozen soil highway subgrade have not been reported yet. The Chinese patent No. 212336116U discloses grouting experimental equipment, which comprises a foundation environment device, a grouting device and a data acquisition system and is used for recording the diffusion rule and the slurry pulse distribution characteristics of grouting liquid in a simulated foundation. However, the device has the defects that the grouting opening of the device is fixed in position, and the grouting depth cannot be flexibly adjusted; secondly, the slurry containing box is formed by splicing a plurality of components of a wood board, angle steel and a steel pipe, repeated tests are not easy to develop, and the square model box has quite remarkable soil body boundary constraint effect; finally, the type and layout form of the sensor are also simpler, if the soil deformation only measures the displacement of the top seat, the deformation characteristics of the near grouting area can not be accurately represented. In addition, chinese utility model patent CN112697652a and CN111006951a respectively disclose an experimental device and a testing method for indoor grouting, which cannot be accurately regulated and controlled in real time on parameters such as grouting flow, grouting pressure, etc.; meanwhile, the cylindrical organic glass barrel is adopted by the model box, and although the phenomenon of stress concentration in soil body can be avoided, the devices do not consider the influence of temperature fields in soil body, namely the coupling effect of simulating complex temperature and groundwater environment on grouting performance cannot be realized, so that a scientific and effective detection platform cannot be provided for the highway subgrade grouting theory and design method in severe cold regions.

Based on the above, research and development of test equipment is urgently needed to develop researches on grouting performance (such as fluidity, permeability, setting time and strength) in low-earth-temperature or frozen-soil highway subgrade in severe cold areas, mechanical mechanism of subgrade structure-filler-slurry interaction under grouting pressure, influence of the whole grouting process on surrounding soil deformation, bearing capacity of adjacent subgrade structure, sedimentation and the like. The related achievements are used for promoting the progress of grouting design methods for the frost heaving, thawing and sinking of highway subgrade and the slurry-casting mud-pumping diseases in the severe cold areas such as northern China, qinghai-Tibet plateau and the like, accelerating the formation of a grouting repair effect evaluation system, and providing theoretical support and decision basis for formulating an optimal control scheme with short construction period, low cost and good repair effect.

Disclosure of Invention

In order to make up for the defects of the highway subgrade grouting theory and technical research in severe cold areas, the utility model aims to provide a highway subgrade grouting performance detection test device and a test method suitable for the severe cold areas, and the test device has the advantages of high temperature controllability, wide application range, strong time correlation of test data and the like.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:

the device comprises a model box and a grouting module arranged above the model box, wherein the grouting module is communicated with an inner cavity of the model box through a grouting pipe;

the model box is provided with a water level gauge, the water level gauge is communicated with an inner cavity of the model box, the bottom of the inner cavity of the model box is a water supplementing chamber, a soil body sample chamber is arranged above the water supplementing chamber, the end part of the grouting pipe stretches into the soil body sample chamber, and the soil body sample chamber and the water supplementing chamber are separated by a porous plate;

the cold bath pipe is arranged in the side wall interlayer space of the model box, antifreeze is filled outside the cold bath pipe, the cold bath pipe is spirally wound in the side wall interlayer space, the upper end of the cold bath pipe is provided with a liquid inlet pipe, the lower end of the cold bath pipe is provided with a liquid outlet pipe, the liquid inlet pipe and the liquid outlet pipe are both communicated with the cold bath instrument, and heat preservation cotton is sleeved outside the side wall and the bottom of the model box;

the soil body sample chamber is internally provided with a plurality of sensor groups, the top of the soil body sample chamber is provided with a surface displacement sensor, the sensor groups and the surface displacement sensor are electrically connected with a processor, and the lower end of the surface displacement sensor is provided with an endoscope.

Therefore, a cold bath pipe is arranged in the interlayer space of the side wall of the model box, the soil body sample chamber is cooled, so that the frozen soil environment in a severe cold region is simulated, the upper end of the cold bath pipe is provided with a liquid inlet pipe, the lower end of the cold bath pipe is provided with a liquid outlet pipe, so that cold bath liquid is prevented from flowing back under the action of gravity, in order to prevent the box from freezing and ensure that the temperature in the box is not influenced by external temperature conditions, the cold bath pipe is filled with the antifreezing liquid, the antifreezing liquid is transformer oil with extremely low freezing point, and a circle of heat preservation cotton is wrapped outside the box. Grouting is carried out on frozen soil in the soil body sample chamber through the grouting module, collected data and images are sent to the processor through the endoscope, the sensor group and the surface displacement sensor, and the processor analyzes the collected stress state, displacement data and images.

The test device provided by the utility model can simulate the roadbed layering grouting process in severe cold regions, monitor the stress strain and surface displacement of the grouting pulse body and surrounding soil under various water temperature conditions and different grouting pressures, analyze the internal stress field and surface displacement distribution characteristics of roadbed soil at different curing times in different grouting stages, and verify the internal interaction mechanics mechanism of a roadbed structure-filler-slurry system, so that the feedback is fed back to engineering practice, and the fine control of grouting repair effect and the evaluation cost selection of an optimal scheme are realized.

Further, be equipped with the drive unit of its axial motion of control on the slip casting pipe, endoscope and drive unit all are connected with comprehensive control platform electricity, flexible slip casting pipe sets up to double-deck hollow screw structure, realizes the precession lift of slip casting mouth through the control head connection comprehensive control platform of tip.

Further, still include the support, the support includes the support bottom plate and is located support baffle of support bottom plate top, support through the support stand between support bottom plate and the support baffle, the model box sets up on the support bottom plate, grouting module sets up on the support baffle, grouting pipe passes support baffle extends to the model box in.

Still further, the processor includes data acquisition ware and image analysis processor, sensor group and surface displacement sensor all with data acquisition ware electricity is connected, data acquisition ware and image analysis processor electricity are connected.

Still further, one side of moisturizing room is equipped with the inlet tube, the opposite side of moisturizing room is equipped with the drain pipe, the inlet tube links to each other with the water tank, the water tank sets up on the elevating platform.

Furthermore, an antifreezing solution inlet valve and an antifreezing solution outlet valve are arranged at the top end of the side wall of the model box.

Still further, the sensor group comprises a plurality of groups of soil pressure boxes, thermometers, hygrometers and pore pressure sensors which are arranged on the same depth plane.

Based on the same inventive concept, the utility model also provides a method for testing by adopting the device for testing the grouting performance of the highway subgrade in the severe cold region, which comprises the following steps:

step one, keeping a grouting pipeline of the grouting module in a closed state before grouting work;

step two, filling test soil samples into a soil body sample chamber and compacting the test soil samples in layers, embedding a sensor group at a preset position for each filling layer of test soil samples, leveling the test soil samples at the uppermost layer, and finishing the filling work of the test soil samples;

thirdly, injecting water into the water supplementing chamber through the water inlet pipe and observing a water level meter, and stopping injecting water and closing the water inlet valve after the water level in the water supplementing chamber is stabilized at an expected value;

step four, starting a cold bath instrument, setting the cold bath temperature, and cooling and freezing the test soil sample in the model box;

step five, vertically inserting a grouting pipe into the middle position of the soil body sample chamber, and arranging a surface displacement sensor and an endoscope on the top of the model box;

step six, starting a grouting module, grouting each layer of test soil sample in the model box in a layering manner after grouting pressure is stable, recording data after grouting of each layer is completed, closing the grouting module after grouting of the last layer is completed, operating an endoscope after data in a processor is stable, and recording soil body surface subsidence deformation images after grouting is completed along a plurality of radial paths;

and step seven, closing the test device, and cleaning the test soil sample to finish the cleaning work of the test device.

Further, before the step two, the method further comprises: and a layer of vaseline is coated on the side wall of the soil body sample chamber.

Still further, after the fifth step, the method further includes: and starting the processor, and resetting the data of the surface displacement sensor to zero after the numerical value received by the processor is stable and reaches a preset value.

The device and the method for detecting and testing the grouting performance of the highway subgrade in severe cold areas have the following advantages:

1) The device can be used for carrying out model test research on the grouting repair of the roadbed in severe cold areas under the combined conditions of the simulated water level and the temperature, and can simulate different earthiness, different freezing temperatures, different underground water levels, various grouting pressures, layered grouting methods and the like.

2) A series of soil physical parameter measuring sensor groups are respectively distributed on different radial layers of the model box by the test device, and the test device comprises: the surface displacement sensor, the soil pressure box, the thermometer, the hygrometer and the pore pressure sensor are used for realizing real-time monitoring and recording of the development rules and characteristics of the stress field distribution, the pore water pressure and the soil surface displacement in the simulated frozen soil roadbed soil layer in the grouting process.

3) The grouting control module in the test device and the model box are arranged in the same vertical direction, so that the actual grouting direction of the roadbed grouting site is reduced; the grouting depth of the telescopic grouting pipe can be adjusted in real time through a control console, and different grouting schemes can be simulated maximally; the grouting process and the development of the stress strain state on the surface and the internal of the soil body are organically unified by using the arranged sensor group, and a more reliable data basis is provided for the follow-up research of the evolution rule of the mechanical characteristics of the roadbed engineering in the whole grouting scheme process.

4) The test device adopts a multi-layer temperature control system, utilizes a small-diameter cold bath copper pipe to encircle the box body, wets the copper pipe in transformer oil with extremely low freezing point, realizes low-temperature freezing simulation, and ensures that other parts outside the soil chamber of the model box are not frozen, so that other modules of the test device can keep working stably.

5) According to the utility model, by applying a set of frozen soil roadbed grouting and detecting system, not only are mechanical and engineering characteristic indexes of different grouting construction schemes and different slurry curing times conveniently, immediately and accurately measured, but also the model soil sample detecting chamber is quickly cleaned and recycled after detection, so that the detecting efficiency is improved, considerable resource waste is reduced, and the environment-friendly design concept is followed.

Drawings

FIG. 1 is a schematic diagram of the structure of the present utility model;

fig. 2 is a top view of the section of the mold box I-I and the internal sensor arrangement of fig. 1.

The figure indicates: 1. a bracket base plate; 2. a support column; 3. a bracket; 4. a slide rail; 5. a model box; 6. an antifreeze inlet valve; 7. an antifreezing solution; 8. thermal insulation cotton; 9. an air outlet valve; 10. a water level gauge; 11. a water level gauge valve; 12. a porous plate; 13. water inlet valve of water tank; 14. water outlet valve of water tank; 15. a lifting table controller; 16. a lifting table; 17. a water level control table; 18. a lifting platform controller; 19. a water inlet pipe; 20. a water supplementing chamber; 21. a drain pipe; 22. a liquid outlet pipe; 23. a liquid inlet pipe; 24. a cold bath tube; 25. a cold bath instrument; 26. an endoscope; 27. a comprehensive control console; 28. a driving unit; 29. a surface displacement sensor; 30. a soil pressure box; 31. a thermometer; 32. a hygrometer; 33. a pore pressure sensor; 34. an impermeable joint; 35. a data collector; 36. an image analysis processor; 37. a motor; 38. a transmission gear; 39. a crankshaft; 40. a connecting rod; 41. a pull rod; 42. a piston; 43. a slurry inlet pipe; 44. a pressure release valve; 45. an oil pressure chamber; 46. a pressure gauge; 47. a pulp discharge valve; 51. grouting modules; 54. a soil body sample chamber; 55. a processor; 56. a sensor group; 57. grouting pipe; 59. a bracket partition; 60. a water tank.

Detailed Description

The present utility model will be described in further detail with reference to the accompanying drawings for a better understanding of the objects, structures and functions of the present utility model.

As shown in fig. 1 and 2, a device for detecting grouting performance of highway subgrade in severe cold region according to this embodiment includes a bracket 3, a mold box 5 and a grouting module 51 disposed above the mold box 5, where the mold box 5 and the grouting module 51 are mounted on the bracket 3, and the mold box 5 and the bracket 3 are made of steel materials, so as to ensure sufficient strength, rigidity and stability on one hand, and to have better heat conducting performance due to metal materials on the other hand. The cross section of the model box 5 is designed into a round shape so as to ensure the consistency of the constraint conditions of the sample soil body. In order to observe the surface displacement of the soil body after grouting, the top of the box is not constrained and is designed to be open. The support 3 comprises a support bottom plate 1 and a support partition plate 59 arranged above the support bottom plate 1, the support bottom plate 1 and the support partition plate 59 are supported by support columns 2, the model box 5 is arranged on the support bottom plate 1, the grouting module 51 is arranged on the support partition plate 59, and the grouting module 51 is communicated with the inner cavity of the model box 5 through a grouting pipe 57.

Specifically, the grouting module 51 includes a motor 37, a crankshaft 39, a connecting rod 40, a pull rod 41, a piston 42, and the like, controls grouting pressure by a pressure gauge 46 and a pressure release valve 44, and adjusts grouting flow by controlling a grouting valve 47. The grouting control module is fixed on the bracket partition 59 by bolts.

The grouting pipe 57 penetrates through the support partition 59 to extend into the model box 5, a driving unit 28 for controlling axial movement of the grouting pipe 57 is arranged on the grouting pipe 57, grouting depth of the grouting pipe 57 can be adjusted by the driving unit 28 according to test requirements, the driving units 28 are electrically connected with the comprehensive control console 27, depth of the telescopic grouting pipe 28 inserted into soil in the model box is adjusted through the comprehensive control console 27 so as to simulate a layered grouting method, the driving unit 28 is arranged into a double-layer hollow screw structure, a control head at the end part is connected with the comprehensive control console 27 to achieve screwing-in lifting of a grouting port, and the comprehensive control console 27 is suspended and fixed at the bottom of the support partition 59 through a steel truss. In order to reduce or eliminate wear between the grouting pipe 57 and the perforations of the bracket partition 59, the perforation holes should be 3-5mm larger than the outer diameter of the grouting pipe 57 and clamped between the gaps by using a silica gel cushion.

The model box 5 is provided with a water level gauge 10, the water level gauge 10 is communicated with an inner cavity of the model box 5, the bottom of the inner cavity of the model box 5 is provided with a water supplementing chamber 20, a soil body sample chamber 54 is arranged above the water supplementing chamber 20, the end part of a grouting pipe 57 stretches into the soil body sample chamber 54, the soil body sample chamber 54 and the water supplementing chamber 20 are separated by a porous plate 12, the porous plate 12 has a certain thickness so as to ensure strength and rigidity, and a supporting block can be arranged at the lower end of the water supplementing chamber 20 for supplementing. The porous plate 12 is provided with water permeable stone and filter paper to prevent soil particles from entering the water supplementing chamber 20. One side of the water supplementing chamber 20 is provided with a water inlet pipe 19, the other side of the water supplementing chamber 20 is provided with a water outlet pipe 21, the water inlet pipe 19 is connected with a water tank 60, and the water tank 60 is arranged on the lifting table 16.

The cold bath pipe 24 is arranged in the interlayer space of the side wall of the model box 5, the antifreeze 7 is filled outside the cold bath pipe 24, and the antifreeze inlet valve 6 and the air outlet valve 9 are arranged at the top end of the side wall of the model box 5. The cold bath pipe 24 is spirally wound in the side wall interlayer space, the upper end of the cold bath pipe 24 is provided with a liquid inlet pipe 23, the lower end of the cold bath pipe 24 is provided with a liquid outlet pipe 22, the liquid inlet pipe 23 and the liquid outlet pipe 22 are communicated with a cold bath instrument 25, and the side wall of the model box 5 and the outside of the box bottom are sleeved with heat preservation cotton 8. A plurality of sensor groups 56 are arranged in the soil body sample chamber 54, and the sensor groups 56 comprise a plurality of groups of soil pressure boxes 30, thermometers 31, hygrometers 32 and pore pressure sensors 33 which are arranged on the same depth plane. The top of soil body sample room 54 is equipped with surface displacement sensor 29, sensor group 56 and surface displacement sensor 29 all are connected with the processor 55 electricity, processor 55 includes data collection station 35 and image analysis processor 36, sensor group 56 and surface displacement sensor 29 all with data collection station 35 electricity is connected, data collection station 35 and image analysis processor 36 electricity is connected. The lower end of the surface displacement sensor 29 is provided with an endoscope 26, the endoscope 26 is electrically connected with the integrated console 27 by a movable probe, so that surface displacement images can be acquired at multiple angles, all acquired image data and digital signals are transmitted to the data acquisition unit 35, and finally reflected to the image analysis processor 36 for further integrated analysis. More preferably, the surface of the sensor and the outer side of the data wire are coated with corrosion-resistant coatings, so that the sensor is prevented from being polluted by slurry; two groups of sensor group wires close to the bottom of the box are led out through the seepage-proof joint of the box wall so as to reduce disturbance to the soil structure.

The method for testing by adopting the device for testing the grouting performance of the highway subgrade in the severe cold region comprises the following steps:

step one, pipeline inspection. The grouting pipe 57 holding the grouting module 51 is kept in a closed state before grouting operation, and the pressure release valve 44 is kept in an open state. The antifreeze inlet valve 6 and the air outlet valve 9 of the model box are kept in an open state, and after the model box is filled with antifreeze 7, the antifreeze inlet valve is closed.

And step two, filling a soil body sample and burying a sensor group. The permeable stone and the filter paper are paved at the bottom of the model box, and the model box 5 is coated with a layer of vaseline on the side wall of the soil body sample chamber 54, so that the model box is convenient to demould after the test. Five layers are filled with test soil samples from bottom to top, the test soil samples are compacted in a layering manner, the surfaces of the test samples are leveled, and the filling work of the test samples is completed. Meanwhile, each layer of soil sample is filled, a sensor group 56 is embedded in a preset position, and cables of the sensor group 56 are led out from the impermeable joints 34 arranged on the side wall of the model box 5. After the arrangement of the sensors in the soil is completed, the model box 5 is moved into the set position of the bracket 3 along the sliding rail 4.

And step three, preparing a water level control module. The tank outlet valve 14 is hose connected to the inlet pipe 19. The water level meter valve 11 is opened, the drain pipe 21 is closed, the water tank inlet valve 13, the water tank outlet valve 14 and the water inlet pipe 19 are opened, the model box 5 is replenished with water, after the water level is stabilized at an expected value, the water inlet pipe 19 is closed, and the water head height is adjusted through the lifting table 16 as required in the test process.

And step four, opening valves of the liquid outlet pipe 22 and the liquid inlet pipe 23, starting the cold bath instrument 25 to cool and freeze soil in the model box, and maintaining the temperature of the cold bath at the moment when the sensor indicates that the temperature reaches the expected value.

And fifthly, data acquisition preparation work. The grouting pipe 57 is vertically inserted into the center of the box, and the driving unit 28 is connected to the integrated console 27. The surface displacement sensor 29 and endoscope 26 are arranged along the radial direction of the mold box and connect the data line to the data collector 35 together with the aforementioned sensor group 56. The data acquisition and image analysis processor 36 is turned on to complete the layout of the data acquisition processing module. And starting a data acquisition system, observing sensor temperature and water level data, and resetting and zeroing the data of the surface displacement sensor 29 after the data reach a preset value and are stable.

Step six, closing the pressure release valve 44 and opening the slurry discharge valve 47; starting the motor 37, starting feeding grouting after grouting pressure is stable, and starting an in-situ performance test of roadbed grouting repair after grouting of soil in the model box is started. The method comprises the following specific steps: the position of the port of the grouting pipe 57 is driven by the driving unit 28 for grouting in layers, a group of stress, hole pressure and surface displacement data are measured after each layer of grouting is completed, and corresponding temperature and humidity conditions are recorded. After the last layer of grouting is completed, the motor 37 and the grouting valve 47 are closed, and grouting is stopped. After the sensor data are stable, the endoscope 26 is operated by the comprehensive control console 27, and the subsidence deformation image of the soil surface after grouting is completed is recorded along a plurality of radial paths.

Step seven, after finishing the above-mentioned soil body grouting repair performance in situ performance detection work, closing the test device of this embodiment, discharging the residual slurry in the grouting pipe 57, taking out the soil body style, and cleaning the model box 5 and the sensor measuring end by using clean water; the power supply is cut off, the cold bath instrument 25 and the valve of the test device are closed, and instrument arrangement work is completed.

It will be understood that the utility model has been described in terms of several embodiments, and that various changes and equivalents may be made to these features and embodiments by those skilled in the art without departing from the spirit and scope of the utility model. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the utility model without departing from the essential scope thereof. Therefore, it is intended that the utility model not be limited to the particular embodiment disclosed, but that the utility model will include all embodiments falling within the scope of the appended claims.

Claims

1. The highway subgrade grouting performance detection test device for the severe cold areas is characterized by comprising a model box (5) and a grouting module (51) arranged above the model box (5), wherein the grouting module (51) is communicated with an inner cavity of the model box (5) through a grouting pipe (57);

the model box (5) is provided with a water level gauge (10), the water level gauge (10) is communicated with an inner cavity of the model box (5), the bottom of the inner cavity of the model box (5) is provided with a water supplementing chamber (20), a soil body sample chamber (54) is arranged above the water supplementing chamber (20), the end part of the grouting pipe (57) stretches into the soil body sample chamber (54), and the soil body sample chamber (54) is separated from the water supplementing chamber (20) by a porous plate (12);

a cold bath pipe (24) is arranged in the side wall interlayer space of the model box (5), antifreeze (7) is filled outside the cold bath pipe (24), the cold bath pipe (24) is arranged in the side wall interlayer space, a liquid inlet pipe (23) is arranged at the upper end of the cold bath pipe (24), a liquid outlet pipe (22) is arranged at the lower end of the cold bath pipe (24), and the liquid inlet pipe (23) and the liquid outlet pipe (22) are both communicated with a cold bath instrument (25);

a plurality of sensor groups (56) are arranged in the soil body sample chamber (54), a surface displacement sensor (29) is arranged at the top of the soil body sample chamber (54), the sensor groups (56) and the surface displacement sensor (29) are electrically connected with a processor (55), and an endoscope (26) is arranged at the lower end of the surface displacement sensor (29).

2. The device for detecting and testing the grouting performance of the highway subgrade in the severe cold area according to claim 1, wherein a driving unit (28) for controlling the axial movement of the grouting pipe (57) is arranged on the grouting pipe, and the endoscope (26) and the driving unit (28) are electrically connected with a comprehensive control console (27).

3. The severe cold district highway subgrade grouting performance detection test device according to claim 1, further comprising a bracket (3), wherein the bracket (3) comprises a bracket bottom plate (1) and a bracket partition plate (59) positioned above the bracket bottom plate (1), the bracket bottom plate (1) and the bracket partition plate (59) are supported by a bracket upright post (2), a model box (5) is arranged on the bracket bottom plate (1), a grouting module (51) is arranged on the bracket partition plate (59), and a grouting pipe (57) penetrates through the bracket partition plate (59) to extend into the model box (5).

4. The severe cold district highway subgrade grouting performance detection test device according to claim 1, characterized in that said processor (55) comprises a data collector (35) and an image analysis processor (36), said sensor group (56) and surface displacement sensor (29) are both electrically connected with said data collector (35), said data collector (35) is electrically connected with said image analysis processor (36).

5. The severe cold district highway subgrade grouting performance detection test device according to claim 1, characterized in that one side of the water supplementing chamber (20) is provided with a water inlet pipe (19), the other side of the water supplementing chamber (20) is provided with a water outlet pipe (21), the water inlet pipe (19) is connected with a water tank (60), and the water tank (60) is arranged on a lifting table (16).

6. The device for detecting and testing the grouting performance of the highway subgrade in the severe cold area according to claim 1 is characterized in that an antifreezing fluid inlet valve (6) and an air outlet valve (9) are arranged at the top end of the side wall of the model box (5).

7. The severe cold district highway subgrade grouting performance test device according to claim 1, characterized in that the sensor group (56) comprises a plurality of groups of soil pressure boxes (30), thermometers (31), hygrometers (32) and pore pressure sensors (33) arranged on the same depth plane.

8. A method of testing by using the device for testing grouting properties of highway subgrade in severe cold areas as claimed in claims 1 to 7, comprising the steps of:

step one, keeping a grouting pipeline of the grouting module (51) in a closed state before grouting work;

step two, filling test soil samples into a soil body sample chamber (54) and compacting the test soil samples in layers, wherein each layer of test soil samples is filled, a sensor group (56) is embedded in a preset position, and the uppermost layer of test soil samples are leveled to finish the filling work of the test soil samples;

thirdly, injecting water into the water supplementing chamber (20) through the water inlet pipe (19) and observing the water level meter (10), stopping injecting water and closing the water inlet valve when the water level in the water supplementing chamber (20) is stabilized at an expected value;

step four, starting a cold bath instrument (25), setting the cold bath temperature, and cooling and freezing a test soil sample in the model box (5);

fifthly, vertically inserting a grouting pipe (57) into the middle position of a soil body sample chamber (54), and arranging a surface displacement sensor (29) and an endoscope (26) on the top of the model box (5);

step six, starting a grouting module (51), grouting each layer of test soil sample in the model box (5) in a layering manner after grouting pressure is stable, recording data after grouting of each layer is completed, closing the grouting module (51) after grouting of the last layer is completed, operating an endoscope (26) after data in a processor (55) is stable, and recording soil body surface sedimentation deformation images after grouting is completed along a plurality of radial paths;

and step seven, closing the test device, removing the test soil sample and completing the cleaning work of the test device.

9. The method for testing grouting performance of highway subgrade in severe cold areas according to claim 8, further comprising, before performing step two: and (3) coating vaseline on the side wall of the soil body sample chamber (54) in a thick way.

10. The method for testing grouting performance of highway subgrade in severe cold areas according to claim 8, further comprising after step five: and starting the processor (55), and resetting the data of the surface displacement sensor (29) to zero when the value received by the processor (55) is stable and reaches a preset value.