A frozen soil frost heaving and thawing settlement deformation monitoring unit and a monitoring and early warning method implemented by the same

Abstract

The application provides a frozen soil frost heaving and thawing settlement deformation monitoring monomer and a monitoring and early warning method realized by the same. At present, there is a lack of real-time monitoring and early warning method for the frozen soil frost heaving amount of the area where various buildings in cold regions are located, which leads to lag of relevant emergency measures and passive remedial treatment. In the application, the lower end of the lower steel column is fixed to the detection plate, the upper end of the lower steel column is arranged in the tubular shell, the composite electrode is arranged in the tubular shell, the composite electrode is arranged at the upper end of the lower steel column, the connecting nail is arranged at the upper end of the composite electrode, the upper end of the first wire is connected with the resistance measuring instrument, the lower end of the first wire penetrates through the top end of the tubular shell and is connected with the connecting nail, the slip ring is sleeved on the composite electrode, the outer circumferential wall of the slip ring is fixed to the inner wall of the tubular shell, the inner wall of the slip ring is processed with a plurality of blind holes, one steel ball is arranged in each blind hole, each steel ball is connected with the bottom of the blind hole through a compression elastic element, each steel ball is connected with the resistance measuring instrument through a second wire, and each steel ball is attached to the outer wall of the composite electrode.

Description

Technical Field

[0001] This invention specifically relates to a single monitoring unit for frozen soil frost heave and thaw settlement deformation and the monitoring and early warning method thereof. Background Technology

[0002] Frozen soil forms due to cold climates. Based on whether it thaws, frozen soil can be divided into seasonally frozen soil and perennial frozen soil. Frozen soil affects 75% of my country's total land area, with perennial frozen soil accounting for 21.5% and the remainder being seasonally frozen soil. The frost heave deformation of soil during winter and the thawing and settlement of soil in spring can damage the foundations of civil engineering projects, thus affecting their service life. Technical measures to prevent frost heave of building foundations mainly include sand replacement, physicochemical methods, thermal insulation, and drainage. Evaluating the feasibility and effectiveness of these methods requires long-term monitoring of the frost heave and thaw settlement deformation of seasonally frozen soil beneath the building to obtain first-hand data. This data serves as an early warning for large-scale frost heave deformation. Therefore, it is essential to monitor the frost heave and thaw settlement deformation of the soil in the project area to take appropriate measures to ensure the safety and reliability of the engineering structures.

[0003] Currently, the methods and devices for on-site observation of frost heave in seasonally frozen soil areas mainly use various displacement sensors such as rod displacement gauges, wire displacement gauges, and eddy current displacement sensors to monitor the change in distance between upper and lower anchor plates to reflect the deformation of seasonally frozen soil, as shown in (CN201510174071.8, CN201910240855.4, CN201910240917.1, CN201910240849.9, CN201910240916.7). There is also a soil frost heave detection device and its detection method without external power supply (CN201910240854.X). This method uses a tension sensor to convert frost heave deformation into force value to achieve monitoring without external power supply. The soil frost heave detection device acquires frost heave data of the frost heave layer at each measuring point at different time periods. Based on the frost heave data fed back from each measuring point, the frost heave deformation of the frozen soil in the test area is obtained. Because the meter head needs to be exposed on the ground surface, this invention is more suitable for on-site investigation and monitoring of frost heave in frozen soil.

[0004] Unlike most on-site monitoring devices for soil frost heave in seasonally frozen soil regions, monitoring the frost heave deformation of building foundations requires consideration of existing buildings on the ground surface. Due to the use of preventive technologies such as sand replacement, physicochemical methods, and thermal insulation, frost heave deformation monitoring devices need to be placed on the surface of the frozen soil layer and below the ground surface. On the one hand, it is not suitable to observe directly from the ground surface; on the other hand, it is greatly affected by rainfall, surface drainage, air humidity, and temperature. In addition, there is a lack of relevant methods for real-time monitoring and early warning of frost heave in the area where the building is located. Currently, it is only possible to take remedial measures after the building foundation settles, which has poor emergency response capabilities, passive handling methods, and high remedial costs. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this paper provides a single monitoring unit for frozen soil frost heave and thaw settlement deformation and its monitoring and early warning method to solve the above problems.

[0006] A single unit for monitoring frozen soil frost heave and thaw settlement deformation includes a detection plate, a lower steel column, a tubular outer shell, a composite electrode, a slip ring, a connecting pin, a first conductor, multiple steel balls, multiple compression elastic elements, and multiple second conductors. The detection plate is horizontally positioned, and the tubular outer shell is vertically positioned above the detection plate. The lower end of the lower steel column is fixedly connected to the detection plate, and the upper end of the lower steel column passes through the tubular outer shell. The composite electrode is located inside the tubular outer shell and at the upper end of the lower steel column. The connecting pin is located at the upper end of the composite electrode. The upper end of the first conductor is connected to... The resistance measuring instrument is connected, and the lower end of the first wire passes through the top of the tubular shell and is connected to the connecting pin. The slip ring is fitted on the composite electrode, and the outer circumferential wall of the slip ring is fixedly connected to the inner wall of the tubular shell. The inner wall of the slip ring is machined with multiple blind holes along its circumference. The length direction of each blind hole is the same as the radial direction of the slip ring. A steel ball is set in each blind hole. Each steel ball is connected to the bottom of the blind hole through a compression elastic element. Each steel ball is connected to the resistance measuring instrument through a second wire. Each steel ball is attached to the outer wall of the composite electrode.

[0007] As a preferred embodiment: multiple strip grooves are machined on the outer circumferential wall of the composite electrode. The length direction of each strip groove is in the same direction as the height direction of the composite electrode. The strip grooves are arranged in a one-to-one correspondence with the steel balls. Each steel ball is placed in its corresponding strip groove and slides back and forth along the length direction of its corresponding strip groove.

[0008] As a preferred embodiment: the lower steel column is a multi-section column, including a bottom column, a first pipe section, an intermediate pipe and a second pipe section. The lower end of the bottom column is fixedly connected to the top surface of the detection plate, the upper end of the bottom column is coaxially connected to the lower end of the intermediate pipe through the first pipe section, and the upper end of the intermediate pipe is coaxially connected to the lower end of the composite electrode through the second pipe section.

[0009] As a preferred embodiment, the lower and upper ends of the tubular outer shell are respectively provided with a first blocking plate and a second blocking plate.

[0010] A monitoring and early warning method is implemented using a single monitoring unit for frozen soil frost heave and thaw settlement deformation according to any one of the specific embodiments one, two, three, or four. The monitoring and early warning method involves determining the location and number of monitoring point groups and the density of multiple monitoring points within each monitoring point group based on the building span, building foundation area, and soil frost heave type in the building area as shown in the construction drawings. A single monitoring unit for frozen soil frost heave and thaw settlement deformation is set up at each monitoring point. By summarizing and analyzing the frost heave data of the frost heave layer at each monitoring point at different time periods obtained from multiple monitoring units, the process of real-time evaluation of the frost heave condition of the frost heave layer where the building is located is completed.

[0011] As a preferred option: The process for determining the soil frost heave type based on the average frost heave rate of the soil in the building area involves reviewing the average frost heave rate of the soil in the building location over the past 5 years. Based on the frost heave rate ranges of 0–1%, 1–3.5%, 3.5–6%, 6–10%, and above 10%, the soil is classified into non-frost heave, weakly frost heave, frost heave, strongly frost heave, and extremely strongly frost heave. Frost heave, strongly frost heave, and extremely strongly frost heave all belong to frost heave-sensitive frozen soil, while non-frost heave and weakly frost heave belong to frost heave-insensitive frozen soil. After determining the number and location of frost heave-sensitive and non-frost heave-insensitive frozen soil areas within the building area, corresponding monitoring point groups are arranged in the frost heave-sensitive and / or non-frost heave-insensitive frozen soil areas, along with the number of monitoring points in each group. The density of monitoring points in the non-frost heave-sensitive frozen soil areas is less than that in the frost heave-sensitive frozen soil areas.

[0012] As a preferred option, there are two ways to determine the location of the measuring point group based on the building span and foundation area in the construction drawings: The first arrangement of the measuring point group: The measuring point group is arranged along the ground beams around the building area. When the span of the building area is within 60m on one side or within 30m on both sides, multiple groups of measuring points and / or multiple measuring points are arranged at intervals on the ground beams around the building. The groups of measuring points or multiple measuring points are arranged circumferentially along the independent foundations under the columns. When the groups of measuring points or multiple measuring points are arranged in a sparse manner, a group of measuring points or a single measuring point is arranged every 4-6m at the four corners of the building area, and a group of measuring points or a single measuring point is arranged every 7-8m in the middle of the ground beams of the building area. When the groups of measuring points or multiple measuring points are arranged in a dense manner, a group of measuring points or a single measuring point is arranged every 1-1.5m at the four corners of the building area, and a group of measuring points or a single measuring point is arranged every 1.5-2m in the middle of the ground beams of the building area. Ensure that all groups of measuring points and / or all measuring points are arranged to cover the area around the building foundation.

[0013] The second arrangement of the measuring point group: The measuring point group is arranged along the ground beams around the building and along the foundation slab. When the span of the building area is greater than 60m on one side or greater than 30m on both sides, multiple groups and / or multiple measuring points are arranged around the ground beams and foundation slab of the building. When the multiple groups and / or multiple measuring points are sparsely arranged, a group or a single measuring point is placed every 4-6m near the four corners of the building area, and a group or a single measuring point is placed every 7-8m in the middle of the ground beams. When the multiple groups and / or multiple measuring points are densely arranged, a group or a single measuring point is placed every 1-1.5m near the four corners of the building area, and a group or a single measuring point is placed every 1.5-2m in the middle of the ground beams. The measuring point groups or measuring points are arranged at intervals in the middle of the foundation slab of the building area, dividing the middle section into grids, with the measuring point positions corresponding to the monitoring points on the ground beams. Once the measuring points are arranged, ensure that all measuring point groups and / or all measuring points cover the perimeter of the foundation and the area of ​​the foundation slab.

[0014] As a preferred option: By summarizing and analyzing the frost heave data of the frost heave layer at different time points obtained from multiple frozen soil frost heave and thaw settlement deformation monitoring units, the process of evaluating the frost heave of the frost heave layer of the building at the same time period or time point is to summarize the frost heave rate data of all monitoring points obtained at the same time period or time point, draw a three-dimensional image of the plane position of each monitoring point and its frost heave deformation rate, and mark the trend of change over time. By analyzing the maximum, minimum, and average values ​​of frost heave and the law of change over time, the frost heave of the frost heave layer in the measurement area can be comprehensively evaluated.

[0015] As a preferred approach: Frost heave data for each measuring point in the frost heave and thaw settlement deformation monitoring unit is obtained, leading to the frost heave force at the corresponding measuring point. The magnitude of the frost heave force on the foundation beams or foundation slab is calculated to determine whether the frost heave force threatens the structural safety and stability. If the bending moment at the structural control section is less than 80% of the designed bending moment, the structure is considered to be in a safe and stable state. If the bending moment at the structural control section is greater than 80% of the designed bending moment, the structure is considered to be in an unsafe and unstable state, and subsequent remedial measures are initiated promptly.

[0016] The beneficial effects of this invention are as follows: I. The frozen soil frost heave and thaw settlement deformation monitoring unit of this invention addresses the lack of existing devices for monitoring soil frost heave deformation. Through the coordinated operation of a detection plate, lower steel column, tubular shell, composite electrode, slip ring, connecting nail, first conductor, multiple steel balls, multiple compression elastic elements, and multiple second conductors, soil deformation is converted into changes in resistance. By establishing the relationship between resistance and deformation, long-term real-time monitoring of soil frost heave deformation is achieved, resulting in more accurate and reliable deformation data. Furthermore, it can operate in low-temperature and humid environments, with minimal impact from temperature and moisture content, filling the gap in devices that can be buried underground in buildings for long-term, stable, and reliable monitoring of frost heave and thaw settlement deformation in seasonally frozen soil regions.

[0017] II. Advantages of using a sliding ring and composite electrode in a single-unit frozen soil frost heave and thaw settlement deformation monitoring system compared to a sliding wire resistor: The multi-point contact measurement of the composite electrode provides accurate resistance; the sliding connection between the steel ball and the composite electrode results in low frictional resistance, ensuring durability and long-term effectiveness; the slip ring is fixed to the outer shell, and multiple compression elastic elements press the steel ball to constrain the composite electrode, ensuring uniform force on the composite electrode and guaranteeing its vertical movement; the slip ring also provides guidance; the composite electrode is the element for measuring resistance, avoiding the insulation problems between the metal wires in a sliding wire resistor, thus making it easier to manufacture, more reliable, and cheaper to produce; the composite electrode is suitable for long-term operation in low-temperature and humid environments.

[0018] III. The single-unit structure for monitoring frozen soil frost heave and thaw settlement deformation is simple, easy to manufacture, and convenient to assemble on the construction site. After assembly, only instrument readings need to be observed, allowing for long-term real-time monitoring. The materials used are corrosion-resistant, have a long service life, and the measurement accuracy meets engineering design requirements.

[0019] Fourth, the present invention uses multiple monitoring points formed by multiple frozen soil frost heave and thaw settlement deformation monitoring units to conduct a comprehensive and real-time monitoring process of frost heave in the building area. This can promptly detect frost heave problems in the building area, and the monitoring has an early warning effect. Once the value is exceeded, relevant reinforcement or other remedial measures can be taken in time, which is conducive to the long-term safe use of the building. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main structure of the monitoring unit for frozen soil frost heave and thaw settlement deformation in this invention; Figure 2 A top view schematic diagram showing the connection relationship between the tubular shell, composite electrode, slip ring, multiple steel balls and multiple compression elastic elements; Figure 3 for Figure 1 Schematic diagram of the cross-sectional structure at point AA; Figure 4 This is a top view of the slip ring structure. Figure 5This is a top view of the detection plate. Figure 6 This is a schematic diagram of the three-dimensional structure of the composite electrode; Figure 7 A schematic diagram of the structure of a single unit for monitoring the frost heave and thaw settlement deformation of frozen soil on an independent foundation; Figure 8 A schematic diagram of the structure of a single unit for monitoring the frost heave and thaw settlement deformation of pile foundation frozen soil. Figure 9 A top-view structural diagram of the arrangement of measuring points along the ground beams around the building area in the detection and early warning method; Figure 10 A top-view structural diagram showing the arrangement of measuring points along the ground beams and foundation slab around the building in the detection and early warning method; Figure 11 This is a flowchart of the monitoring and early warning method of the present invention; Figure 12 This is a schematic diagram illustrating the principle of calculating uniformly distributed loads on a beam by classifying the load distribution into two equivalent types in the monitoring and early warning method. Figure 12 'a' is a distribution diagram when the actual load size distribution approximates a triangle, which can be equivalent to the uniformly distributed load size on the right side for calculation. q represents the maximum value of the actual load, and q represents the equivalent uniformly distributed load. Figure 12 b is a distribution diagram when the actual load magnitude distribution approximates a trapezoid. In the diagram, where multiple load values ​​are similar, they are equivalent to the uniformly distributed load magnitude on the right side for calculation. q is the maximum value of the actual load, q is the equivalent uniformly distributed load, and a is the distance from the end of the point where the load value decreases. Figure 13-1 A schematic diagram illustrating the monitoring point layout and calculation principle of the monitoring and early warning method applied to the board; Figure 13-2 This is a schematic diagram of the load-bearing principle of plate 1-1. Figure 13-3 This is a schematic diagram of the load-bearing principle of the plate in the 1-2 direction.

[0021] In the diagram: 1-Detection plate; 2-Lower steel column; 2-1-Bottom column; 2-2-First pipe section; 2-3-Intermediate pipe; 2-4-Second pipe section; 3-Tubular outer shell; 4-Composite electrode; 5-Slip ring; 6-Connecting nail; 7-First conductor; 8-Steel ball; 9-Compression elastic element; 10-Second conductor; 11-Blind hole; 12-Strip groove; 13-First blocking plate; 14-Second blocking plate; 22-Upper steel column; 24-Shaped hinge wire; 30-Frozen soil frost heave and thaw settlement deformation monitoring unit; 31-Resistance measuring instrument; 32-Fixed rigid foundation; 33-Thin steel column; 34-Pointer plate; 35-Column; 36-Independent foundation under column; 37-Foundation beam; 38-Frozen soil layer; 39-Non-frozen soil layer; 40-Conductive sheet; 41-Pile foundation. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0023] Specific implementation method one: Combining Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13-1 , Figure 13-2 and Figure 13-3This embodiment describes a detection plate 1, a lower steel column 2, a tubular outer shell 3, a composite electrode 4, a slip ring 5, a connecting nail 6, a first wire 7, multiple steel balls 8, multiple compression elastic elements 9, and multiple second wires 10. The detection plate 1 is horizontally arranged and has a cross-shaped plate body. Its structural shape facilitates contact with soil in multiple positions and directions, allowing it to move under the influence of frost heave of soil in multiple positions and directions. The tubular outer shell 3 is vertically arranged above the detection plate 1. The lower steel column 2 is used to connect the tubular outer shell 3 and the detection plate 1. The lower end of the lower steel column 2 is fixedly connected to the detection plate 1, and the upper end of the lower steel column 2 passes through the tubular outer shell 3. The upper end of the tubular outer shell 3 is connected to an upper steel column 22, which provides the threading position and space for each wire. The composite electrode 4 is disposed inside the tubular outer shell 3 and is located at the upper end of the lower steel column 2. The connecting pin 6 is located at the upper end of the composite electrode 4. The upper end of the first wire 7 is connected to the resistance measuring instrument, which is an existing device used to measure the specific resistance value. The lower end of the first wire 7 passes through the top end of the tubular outer shell 3 and is connected to the connecting pin 6. The slip ring 5 is fitted onto the composite electrode 4. The outer circumferential wall of the slip ring 5 is fixedly connected to the inner wall of the tubular outer shell 3. The inner wall of the slip ring 5 is machined with multiple blind holes 11 along its circumferential direction. The length direction of each blind hole 11 is in the same direction as the radial direction of the slip ring 5. A steel ball 8 is correspondingly disposed in each blind hole 11. Each steel ball 8 is connected to the bottom of the blind hole 11 through a compression elastic element 9. Each steel ball 8 on the slip ring 5 is connected to the resistance measuring instrument through a second wire 10. The steel ball 8 and the second wire 10 are not directly connected. The second wire 10 only needs to be connected to the surface of the slip ring 5 in the vicinity of the steel ball 8. Each steel ball 8 is attached to the outer wall of the composite electrode 4.

[0024] In this embodiment, the number of steel balls 8 is multiple, not less than four. The specific number is selected and configured according to the size and specifications of the frozen soil frost heave and thaw settlement deformation monitoring unit 30.

[0025] In this embodiment, the shape of each steel ball 8 facilitates its effective fit with the composite electrode 4, reducing the amount of wear caused by friction during its movement.

[0026] Furthermore, multiple strip-shaped grooves 12 are machined on the outer circumferential wall of the composite electrode 4. The strip-shaped grooves 12 are grooves that cooperate with the steel balls 8, and are used to provide a directional channel for the steel balls 8 to move stably and effectively on the composite electrode 4 without deviating from the movement trajectory. The length direction of each strip-shaped groove 12 is in the same direction as the height direction of the composite electrode 4. The strip-shaped grooves 12 are set one-to-one with the steel balls 8. Each steel ball 8 is set in its corresponding strip-shaped groove 12, and each steel ball 8 slides back and forth along the length direction of its corresponding strip-shaped groove 12.

[0027] The working principle of the composite electrode 4 in this embodiment is as follows: The composite electrode 4 is a dynamic component that moves during operation, while the tubular outer shell 3, slip ring 5, and multiple steel balls 8 are static components. The movement of the steel balls 8 is determined by the movement of the composite electrode 4. When soil frost heave occurs in the area where the monitoring unit 30 for frozen soil frost heave and thaw settlement deformation occurs, the frost heave change is directly reflected by the detection plate 1. The rise and fall of the detection plate 1 are directly transmitted to the composite electrode 4 through the lower steel column 2. The composite electrode 4 and the detection plate 1 move synchronously. Since the position of the steel balls 8 remains unchanged, the movement of the composite electrode 4 causes the position of the steel balls 8 on the composite electrode 4 to change, thereby generating a resistance change value that is reflected on the resistance measuring instrument, facilitating real-time acquisition of resistance changes.

[0028] The compression elastic element 9 is in a compressed state throughout the entire use process, in order to ensure that its corresponding steel ball 8 can be squeezed and pressed against the composite electrode 4 in real time, thereby achieving effective monitoring.

[0029] Furthermore, the lower steel column 2 is a multi-section column, comprising a base column 2-1, a first tube section 2-2, an intermediate tube 2-3, and a second tube section 2-4. The lower end of the base column 2-1 is fixedly connected to the top surface of the detection plate 1. The upper end of the base column 2-1 is coaxially connected to the lower end of the intermediate tube 2-3 via the first tube section 2-2. The upper end of the intermediate tube 2-3 is coaxially connected to the lower end of the composite electrode 4 via the second tube section 2-4. The multi-section structure of the lower steel column 2 is designed for easy disassembly, thus facilitating reuse.

[0030] Furthermore, a first blocking plate 13 and a second blocking plate 14 are respectively provided at the lower and upper ends of the tubular outer shell 3. The first blocking plate 13 is used to block the lower end of the tubular outer shell 3, and the second blocking plate 14 is used to block the upper end of the tubular outer shell 3. This facilitates the smooth installation of relevant internal components of the tubular outer shell 3, and also enables reasonable wiring and isolation from the external humid environment after the internal components are installed.

[0031] Furthermore, the slip ring 5 is a component formed from a ring-shaped steel block, with multiple blind holes 11 machined along its circumference on its inner wall. The number of blind holes 11 is no less than four, and the dimensions of the blind holes 11 are matched to the dimensions of the steel ball 8 to ensure that the steel ball 8 can smoothly move within the blind holes 11 without shifting. The blind holes 11 provide an installation position for the compression elastic element 9 and also restrict the position of the steel ball 8, preventing significant shifts and ensuring that the steel ball 8 can slide on the surface of the composite electrode. The outer wall of the slip ring 5 is fixed to the tubular outer shell 3 with screws.

[0032] Furthermore, a hole is machined in the lower steel column 2, and a pin is inserted into the hole. The tubular outer shell 3 contacts the pin. After the pin is inserted, it is used to lock the lower steel column 2, thereby preventing the position of the frozen soil frost heave and thaw settlement deformation monitoring unit 30 from moving up and down during the installation process, thus directly avoiding the change of the initial resistance value. After the frozen soil frost heave and thaw settlement deformation monitoring unit 30 is installed, the pin is pulled out and real-time monitoring of the frozen soil begins.

[0033] Specific Implementation Method Two: Combining Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13-1 , Figure 13-2 and Figure 13-3 This embodiment describes a monitoring and early warning method that determines the location, number, and density of monitoring point groups based on the building span, foundation area, and soil frost heave type in the building area as shown in the construction drawings. Each monitoring point is equipped with a corresponding frozen soil frost heave and thaw settlement deformation monitoring unit 30. By summarizing and analyzing the frost heave data of each monitoring point at different time periods obtained from multiple frozen soil frost heave and thaw settlement deformation monitoring units 30, the process of real-time evaluation of the frost heave condition of the frost heave layer where the building is located is completed.

[0034] In this embodiment, the process of determining the frost heave type of soil based on the average frost heave rate of the soil in the building area involves consulting the average frost heave rate of the soil in the building location over the past 5 years. Based on the frost heave rate ranges of 0–1%, 1–3.5%, 3.5–6%, 6–10%, and above 10%, the soil is classified into non-frost heave, weakly frost heave, frost heave, strongly frost heave, and extremely strongly frost heave. Frost heave, strongly frost heave, and extremely strongly frost heave all belong to frost heave-sensitive frozen soil, while non-frost heave and weakly frost heave belong to frost heave-insensitive frozen soil. After determining the number and location of frost heave-sensitive and non-frost heave-insensitive frozen soil areas within the building area, corresponding measurement point groups and the number of measurement points in each measurement point group are arranged within the frost heave-sensitive and / or non-frost heave-insensitive frozen soil areas. The density of measurement point arrangement in the non-frost heave-insensitive frozen soil areas is less than that in the frost heave-sensitive frozen soil areas.

[0035] In this invention, multiple frozen soil frost heave and thaw settlement deformation monitoring units 30 are in use, and multiple frozen soil frost heave and thaw settlement deformation monitoring units 30 form a monitoring system.

[0036] Combination Figure 7 and Figure 8 As shown, based on the type of building foundation in the construction drawings (either an independent column foundation 36 or a pile foundation 41), two typical usage processes of forming a monitoring system from multiple frozen soil frost heave and thaw settlement deformation monitoring units 30 are specifically explained: The first application of the monitoring system is when the building foundation is an independent foundation, i.e., a shallow foundation with a depth of less than 5m. The foundation is above the frost line 38, and the impact of frost heave on the foundation cannot be ignored. When the frost line 38 undergoes frost heave and thaw settlement deformation, the independent foundation 36 under the column will experience corresponding vertical displacement, and the column 35 will also experience slight displacement. Based on structural deformation coordination, the foundation beam 37 will also experience slight vertical displacement. Therefore, it is necessary to install individual monitoring units 30 for frost heave and thaw settlement deformation at the four corners of the building's columns 35 to monitor the slight displacement of the columns and to correct the frost heave and thaw settlement deformation monitoring results at the foundation beams 37 around the building. The monitoring device for the column above ground is arranged as follows: a conductive sheet 40 with the same conductive coating as the composite electrode 4 is made and fixed at a certain position above ground on the column 35. A separate thin steel column 33 is arranged on the outside of the column 35, with its lower end extending into the non-frozen soil layer 39 to ensure that it does not affect the vertical displacement when the frozen soil undergoes frost heave and thaw settlement deformation. A fixed rigid support 32 is arranged at the upper end, and a pointer piece 34 is connected to the conductive sheet 40 to ensure that the position of the pointer piece 34 is fixed. A wire is connected to the upper end of the conductive sheet 40 and the pointer piece 34. The other end of the wire is connected to a resistance measuring instrument 31 to measure the resistance. As the column 35 moves up and down, the conductive sheet 40 slides relative to the pointer piece 34, and the resistance measuring instrument 31 measures the change in resistance. When the measured resistance value changes by ΔR, it indicates that the column 35 has generated a vertical displacement of Δs. According to the deformation coordination of the structure, the column 35 and the foundation beam 37 are a whole, so the vertical displacement of the corresponding beam position can be obtained as Δs. Then, the location of the measuring point group is determined according to the building span and building foundation area in the construction drawings. Then, this displacement Δs is used to correct the frost heave deformation ΔH of the frozen soil layer 38 under the beam measured by the single monitoring unit 30 for frost heave and thaw settlement deformation.

[0037] The second monitoring method is used when the building foundation is a pile foundation 41, i.e., a deep foundation with a depth greater than 5m. The superstructure transfers the load to the deeper non-frozen soil layer 39 below the frozen soil layer 38 through the pile foundation 41. In this case, the influence of frost heave of the frozen soil layer 38 on the vertical displacement of the foundation columns can be ignored. The location of the measuring point group can be directly determined based on the building span and foundation area in the construction drawings.

[0038] In this embodiment, there are two methods for determining the location of the measuring point group based on the building span and foundation area in the construction drawings: The first arrangement of the measuring point group is applicable to both existing and under-construction buildings. Specifically, the measuring point group is arranged along the ground beams around the perimeter of the building area. For existing buildings, pits are dug near the surrounding ground beams to bury the frozen soil heave and thaw settlement deformation monitoring unit 30 below the ground surface. The monitoring plate 1 is placed on the upper surface of the frozen soil layer 38, and the frozen soil heave and thaw settlement deformation monitoring unit 30 is fixed to the foundation beam 37. For buildings under construction, the frozen soil heave and thaw settlement deformation monitoring unit 30 is directly fixed and connected and buried on the upper surface of the frozen soil layer 38 during the construction of the ground beams. The surrounding ground beams are the underground foundation beams 37.

[0039] When the span of the building area is within 60m on one side or within 30m on both sides, multiple groups of measuring points and / or multiple measuring points are arranged at intervals on the ground beams around the building. The groups of measuring points or multiple measuring points are arranged circumferentially along the independent foundations under the columns. When the groups of measuring points or multiple measuring points are arranged in a sparse manner, a group of measuring points or a single measuring point is arranged every 4-6m at the four corners of the building area, and a group of measuring points or a single measuring point is arranged every 7-8m in the middle of the ground beams of the building area. When the groups of measuring points or multiple measuring points are arranged in a dense manner, a group of measuring points or a single measuring point is arranged every 1-1.5m at the four corners of the building area, and a group of measuring points or a single measuring point is arranged every 1.5-2m in the middle of the ground beams of the building area. Ensure that all groups of measuring points and / or all measuring points are arranged to cover the area around the building foundation.

[0040] The second arrangement of the measuring point group is applicable to the layout of buildings, specifically, the measuring point group is arranged along the ground beams around the building and the foundation slab: For buildings under construction, the frozen soil frost heave and thaw settlement deformation monitoring unit 30 is directly fixed and embedded into the upper surface of the frozen soil layer 38 during the construction of the ground beams and foundation slab. The surrounding ground beams are also the foundation beams 37.

[0041] When the span of the building area is 60m or more on one side, or 30m or more on both sides, multiple groups and / or multiple measuring points are arranged around the ground beams and foundation slab of the building. When the multiple groups and / or multiple measuring points are arranged in a sparse manner, a group or a single measuring point is arranged every 4-6m near the four corners of the building area, and a group or a single measuring point is arranged every 7-8m in the middle of the ground beams of the building area. When the multiple groups and / or multiple measuring points are arranged in a dense manner, a group or a single measuring point is arranged every 1-1.5m near the four corners of the building area, and a group or a single measuring point is arranged every 1.5-2m in the middle of the ground beams of the building area. The measuring point group or measuring points in the middle of the foundation slab of the building area adopts the plastic hinge line arrangement method of the slab. First, the slab is divided into grids according to the measuring point positions on the beam. The measuring points of the slab are arranged at the intersection of the longitudinal lines of the grid and the plastic hinge lines. After the measuring points are arranged, ensure that all measuring point groups and / or all measuring points cover the perimeter of the foundation and the area of ​​the foundation slab.

[0042] Specific Implementation Method 3: This implementation method is a further limitation of Specific Implementation Method 2. In this implementation method, when the monitoring and early warning method is in real-time monitoring, when the detection plate 1 is in the initial position in the frozen soil layer 38, the output resistance of the composite electrode 4 is set to 500Ω. When the frozen soil layer 38 rises by 20cm, the output resistance of the composite electrode 4 is 0Ω. When the frozen soil layer 38 falls by 20cm, the output resistance of the composite electrode 4 is 1000Ω.

[0043] When the detection plate 1 is initially positioned in the frozen soil layer 38, the output resistance of the composite electrode 4 is 500Ω. The specific operation process is as follows: A hole is machined in the lower steel column 2, and a pin is inserted into the hole. The tubular outer shell 3 contacts the pin, and the pin is inserted in front of the pre-embedded detection plate 1. The composite electrode 4 outputs a measuring resistance of 500Ω. After the pre-embedded detection plate 1 is installed, the pin is pulled out, and real-time monitoring of the frozen soil begins. When the measured resistance value changes by ΔR, the corresponding deformation of the frozen soil layer 38 is ΔH. By consulting or measuring the local frozen soil layer thickness, the minimum value is selected as the frozen soil layer thickness H0, and the frost heave rate of the soil at this monitoring point is obtained as ΔL=ΔH / H0. By analogy, the frost heave rate data of all monitoring points are obtained at the same time point. The planar position of each measuring point and its frost heave deformation rate are plotted into a three-dimensional image, and the trend of change over time is marked. By analyzing the maximum, minimum, and average values ​​of frost heave and the law of change over time, the frost heave situation of the frost heave layer in the measurement area can be comprehensively evaluated. The system provides a clear and quantitative assessment of the degree of frost heave deformation in the test area, along with guidance. When the frost heave deformation in a localized area monitored at a certain monitoring point exceeds the average frost heave rate of the soil in the region over the past five years, an early warning is issued. In this case, the stress generated by the frost heave deformation in that area on the foundation beam or foundation slab should be calculated to determine whether it will harm the structural stability. Corresponding technical measures can then be taken to reduce the impact of frost heave, thereby achieving frost heave prevention for the foundation structure of subsequent engineering construction in the region and providing remedial measures for the current building.

[0044] In this embodiment, the frost heave data of the frost heave layer at each measuring point at different time periods is obtained by monitoring the frost heave device. The frost heave data fed back by each measuring point are summarized to obtain a comprehensive picture of the reliability and subsequent utilization of the frozen soil frost heave in the test area.

[0045] Specific Implementation Method Four: This implementation method is a further limitation of Specific Implementation Method Three. In this implementation method, the planar position of each measuring point and its frost heave deformation rate are plotted into a three-dimensional image, and the changing trend over time is marked. By analyzing the maximum, minimum, and average values ​​of frost heave and the law of change over time, the frost heave situation of the frost heave layer in the measuring area can be comprehensively evaluated. The specific process is as follows: At the same time, frost heave rate data of all monitoring points are obtained, and the frost heave deformation diagram of the whole plane is drawn by drawing software. By comparing the maximum, minimum and average values ​​of frost heave, the maximum value and its position are selected and marked.

[0046] When the frost heave deformation of a localized area monitored at a certain monitoring point in the test area is excessive, exceeding the average frost heave rate of the soil in the region over the past 5 years, an early warning is issued, and the magnitude of the frost heave force generated by this deformation on the foundation beam or foundation slab is calculated. Simultaneously, the trend of frost heave rate over time is plotted. When the frost heave rate of a certain monitoring point consistently exceeds the average, it is placed under close observation, and the magnitude of the frost heave force generated on the foundation beam or foundation slab is calculated to determine whether it will harm structural stability. The specific calculation method is as follows: Beam calculations: Based on the frost heave deformation of frozen soil, calculate the corresponding frost heave force according to Equation 1-1: (1-1) in: P —Normal frost heave force, in N; ΔH —The frost heave deformation of the frost-susceptible soil layer at the monitoring point, in mm; E —The elastic modulus of frozen soil, in N / mm² 2 μ —Poisson's ratio of frost-susceptible soil layers; —The side length of the monitoring plate, in mm.

[0047] When the monitoring system is used in the first mode, the measured vertical displacement of the column is: Δs Then you need to use ΔH - Δs The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated. When the monitoring system is used in the second mode, it is directly used... ΔH Perform frost heave calculations.

[0048] Due to seasonal freeze-thaw cycles, the pore water inside the soil undergoes transformation between the solid and liquid phases, resulting in significant deformation and damage to building foundations, ground surfaces, and other components. Therefore, during building foundation construction, backfilling or frost heave prevention measures are taken at the points where the building contacts the frozen soil layer 38. In this case, the intermediate layer between the foundation beam or foundation slab and the frozen soil layer 38 serves as a buffer layer.

[0049] When a buffer layer is present, the amount of frost heave deformation absorbed by the buffer layer is: Δh Then you need to use ΔH-Δh The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated.

[0050] like Figure 11As shown, based on the obtained frost heave force and for safety considerations, the largest load is selected as the actual load at a measured point, denoted as Pi. The load distribution is divided into two equivalent uniformly distributed loads on the beam for calculation. When calculating according to elastic theory, the trapezoidal or triangular loads on the beam can first be converted into equivalent uniformly distributed loads based on the condition of equal support rotation angles, and then calculated using structural mechanics methods. For multi-span continuous beams, the support bending moments under the equivalent uniformly distributed loads can be obtained from tables. Then, using the obtained support bending moments and the actual load of each span, the shear force and section bending moment of the beam are calculated according to equilibrium conditions, thereby determining whether the stress meets the design safety range of the beam.

[0051] in, Figure 11 'a' is a distribution diagram when the actual load size distribution approximates a triangle, which can be equivalent to the uniformly distributed load size on the right side for calculation. q is the maximum value of the actual load, and q is the equivalent uniformly distributed load; q is calculated according to Equation 1-2. Figure 11 b is a distribution diagram when the actual load magnitude distribution approximates a trapezoid. In the diagram, where multiple load values ​​are similar, they are equivalent to the uniformly distributed load magnitude on the right side for calculation. q represents the maximum actual load, and q represents the equivalent uniformly distributed load. a q is the distance from the end of the point where the load value decreases; it is calculated according to Equation 1-3.

[0052] (1-2) , (1-3) By calculating the internal forces, the bending moment envelope diagram of the beam under load is drawn. When the bending moment envelope diagram of the beam is less than 80% of the beam's design bending moment resistance, the beam is considered to be in a safe state. When it is greater than 80% of the beam's design bending moment resistance, an early warning should be issued so that relevant remedial measures can be taken.

[0053] like Figure 12-1 , Figure 12-2 and Figure 12-3 The diagram shows the specific layout and calculation process of monitoring points on the beam's upper slab: Considering that when the plate is about to fail, the plastic hinge line 24 occurs at the point of maximum bending moment, and the deformation of the plate is concentrated on the plastic hinge line 24, the presence of the plastic hinge line 24 makes the several plates of the structure a geometrically variable system. Therefore, the monitoring points are installed on the plastic hinge lines 24 of the plate, namely AE, BE, CE, DE, and EF.

[0054] For segment EF, the average deflection of the segment is calculated according to equation 1-4: (1-4) Where: ν—average deflection ΔHi —Frost heave deformation of frost-susceptible soil layers at different monitoring points n — Number of monitoring points When the monitoring system is used in the first mode, the measured vertical displacement of the column is: Δs Then you need to use ΔH i - Δs The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated. When the monitoring system is used in the second mode, it is directly used... Δ H i Perform frost heave calculations.

[0055] When a buffer layer is present, the amount of frost heave deformation absorbed by the buffer layer is: Δh Then you need to use ΔH i -Δh The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated.

[0056] Since the slab is surrounded by beams, it can be considered as an equivalent two-way slab with four simply supported segments. For the elastic limit analysis method, the magnitude of the obtained shear force can be used to derive the equivalent uniformly distributed load, which can then be calculated using formula 1-5. (1-5) The equivalent uniformly distributed load obtained is then calculated according to formula 1-6: (1-6) in: B c —This refers to the bending stiffness of the two-way slab strip section; l ox —Distance of the short side of the board; l oy —Distance along the longer side of the board; β ν 、β M --according to l ox 、l oy The relative value is determined by a coefficient.

[0057] To determine whether the current stress state meets the design safety range of the slab, if the bending moment envelope of the slab is less than 80% of the slab's design bending moment resistance, the slab is determined to be in a safe and stable state. If the bending moment envelope of the slab is greater than 80% of the slab's design bending moment resistance, the slab is determined to be in an unsafe and unstable state, requiring timely warning and appropriate remedial measures.

[0058] Specific Implementation Method Five: This implementation method is a further limitation of Specific Implementation Methods One, Two, Three, or Four. The structural composition and preparation process of the composite electrode in this implementation method are as follows: The composite electrode 4 comprises a phenolic resin cylinder and a conductive coating. The upper surface of the phenolic resin cylinder and the interior of the strip-shaped groove 12 are uniformly coated with a conductive coating sensitive to resistivity changes, thus connecting the upper surface of the cylinder and the strip-shaped groove 12. The phenolic resin cylinder has a radius of 2-10 mm and a length of 5-50 cm. The surface of the phenolic resin cylinder is evenly divided into four grooves, each 1-5 mm wide and 1-5 mm deep, with a length consistent with the length of the phenolic resin cylinder.

[0059] The conductive coating comprises the following raw materials by weight: 80-98% graphite, 1-5% conductive carbon black, 3-15% binder, and 3-8% ceramic particles. The sum of the mass fractions of the above components is 100%, and the particle size of the ceramic particles is 5-25 nm.

[0060] The graphite particle size (D50) is 10~18 μm. The conductive carbon black has a specific surface area of ​​50~80 m² / g. The binder is at least one or two of styrene-butadiene rubber, sodium carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylic acid, or thermoplastic elastomer.

[0061] The preparation steps of composite electrode 4 are as follows: Step 1: Weigh the raw materials according to the specified weight ratio and mix them thoroughly; Step 2: Add the mixed raw materials from Step 1 to the solvent and stir for 1-8 hours to obtain the coating slurry.

[0062] Step 3: Apply the coating slurry obtained in step 2 into the groove of the phenolic resin cylinder, and then dry it at a constant temperature of 125℃ for 10~60 minutes to form a conductive coating product with a thickness of 1~5mm.

[0063] The solvent in step 2 is at least one of N-methylpyrrolidone, water, and dimethylformamide.

[0064] The following embodiments are described in conjunction with the beneficial effects of the present invention: Example

[0065] The test area in this embodiment is the frozen soil area of ​​X region in H city in Northeast China, where a frozen soil frost heave and thaw settlement deformation monitoring device is installed on the ground beam of the building.

[0066] The specific operation process of monitoring frozen soil frost heave and thaw settlement deformation using the frozen soil frost heave and thaw settlement deformation monitoring device is as follows: According to the relevant design requirements, four steel balls 8 are configured inside the slip ring 5.

[0067] Step 1: Before installing the frozen soil frost heave and thaw settlement deformation monitoring unit 30, connect the frozen soil frost heave and thaw settlement deformation monitoring unit 30 to the resistance measuring instrument, move the detection plate 1, record the resistance change, and establish a calibration curve, that is, the corresponding relationship curve between the moving distance of the detection plate 1 and the resistance change.

[0068] The testing plate 1 is placed on the upper surface of the frozen soil being tested. The upper steel column 22 is perpendicular to the frozen soil layer 38, and the upper end of the upper steel column 22 is fixed to the foundation beam 37 with steel plate 18 and screws. Two types of wires leading out from the lower steel column 2 are respectively connected to the resistance measuring instrument.

[0069] The outer wall of the upper steel column 22 is connected to the tubular outer shell 3 through the second blocking plate 14, which is an asphalt sealing plate.

[0070] The detection plate 1 is cross-shaped and made of stainless steel. It is placed on the upper surface of the frozen soil layer 38 of the soil being tested. A lower steel column 2 is welded to the center of the detection plate 1. The upper end of the first pipe section 2-2 of the lower steel column 2 is threaded to the lower end of the second pipe section 2-4. The upper end of the second pipe section 2-4 is threaded to the lower end of the composite electrode 4. The lower steel column 2 passes through the first blocking plate 13. A through hole is machined at the center of the first blocking plate 13. The lower steel column 2 is clearance-fitted with the through hole. The composite electrode is inserted into the slip ring 5. The strip groove 12 of the composite electrode 4 is slidably connected to the steel ball 8 of the slip ring 5. The composite electrode 4 has a connecting pin 6 at its upper end, and the upper end of the tubular outer shell 3 is threadedly connected to the second blocking plate 14. The upper steel column 22 contains two types of wires: one end of the first wire 7 is connected to the connecting pin 6, and one end of the second wire 10 is connected to the upper surface of the slip ring 5, ensuring that each connection point of the second wire 10 is close to the location of a steel ball 8. The upper ends of the first wire 7 and the four second wires 10 are all connected to a resistance measuring instrument. By measuring the change in resistance of the composite electrode 4, the change in frost heave and thaw settlement of the frozen soil layer 38 in the soil can be obtained. Both the tubular outer shell 3 and the first blocking plate 13 are made of engineering plastics.

[0071] Step Two: Connect four second wires 10 to four resistance measuring instruments respectively. Take the average of the four readings as the final result. Discard any reading that is too high or too low, and take the average of the other three readings as the final result. In the frozen soil layer 38, the output resistance of the composite electrode 4 at the initial position of the detection plate 1 is set to 500 ohms. When the frozen soil layer 38 rises by 20 cm, the output resistance of the composite electrode 4 is 0 ohms; when the frozen soil layer 38 falls by 20 cm, the output resistance of the composite electrode 4 is 1000 ohms.

[0072] The method for determining the initial position of the detection plate 1 and the output resistance of the composite electrode 4 in the frozen soil layer 38 to be 500 ohms is as follows: A hole is made in the lower steel column 2, and a pin is inserted into the hole. The tubular outer shell 3 contacts the pin. The pin is inserted before the pre-embedded detection plate 1 to achieve a temporary positioning effect. The output measurement resistance of the composite electrode 4 is 500 ohms. After the detection plate 1 is pre-embedded, the pin is removed, and real-time monitoring of the frozen soil begins. When the measured resistance value changes, it corresponds to the deformation occurring in the corresponding frozen soil layer 38. The trend of change over time is marked to quantitatively evaluate the degree of frost heave and thaw settlement deformation in the test area, providing real-time and timely quantitative early warning opinions.

Claims

1. A monitoring and early warning method for frozen soil frost heave and thaw settlement deformation monitoring unit, characterized in that: The monitoring and early warning method is to determine the location, number, and density of the monitoring point group based on the building span, building foundation area, and soil frost heave type in the building area in the construction drawings. Each monitoring point is equipped with a frozen soil frost heave and thaw settlement deformation monitoring unit (30). By summarizing and analyzing the frost heave data of each monitoring point in the frost heave layer at different time periods obtained from multiple frozen soil frost heave and thaw settlement deformation monitoring units (30), the process of real-time evaluation of the frost heave status of the frost heave layer where the building is located is completed. There are two ways to determine the location of the measuring point group based on the building span and foundation area in the construction drawings: The first arrangement of the measuring point group: The measuring point group is arranged along the ground beams around the building area. When the span of the building area is within 60m on one side or within 30m on both sides, multiple groups of measuring points and / or multiple measuring points are arranged at intervals on the ground beams around the building. The groups of measuring points or multiple measuring points are arranged circumferentially along the independent foundations under the columns. When the groups of measuring points or multiple measuring points are arranged in a sparse manner, a group of measuring points or a single measuring point is arranged every 4-6m at the four corners of the building area, and a group of measuring points or a single measuring point is arranged every 7-8m in the middle of the ground beams of the building area. When the groups of measuring points or multiple measuring points are arranged in a dense manner, a group of measuring points or a single measuring point is arranged every 1-1.5m at the four corners of the building area, and a group of measuring points or a single measuring point is arranged every 1.5-2m in the middle of the ground beams of the building area, ensuring that all groups of measuring points and / or all measuring points cover the area around the building foundation after they are arranged. The second arrangement of the measuring point group: The measuring point group is arranged along the ground beams around the building and along the foundation slab. When the span of the building area is more than 60m on one side or more than 30m on both sides, multiple groups and / or multiple measuring points are arranged around the ground beams and foundation slabs of the building. When the multiple groups and / or multiple measuring points are sparsely arranged, a group or a single measuring point is arranged every 4-6m near the four corners of the building area, and a group or a single measuring point is arranged every 7-8m in the middle of the ground beams of the building area. When the multiple groups and / or multiple measuring points are densely arranged, a group or a single measuring point is arranged every 1-1.5m near the four corners of the building area, and a group or a single measuring point is arranged every 1.5-2m in the middle of the ground beams of the building area. The measuring point groups or measuring points are arranged at intervals in the middle of the foundation slab of the building area, and the middle part is divided into grids, with the measuring point groups or measuring points arranged at intervals. The position of the measuring points corresponds to the position of the monitoring points on the ground beams. After the measuring points are arranged, ensure that all measuring point groups and / or all measuring points cover the perimeter of the foundation and the area of ​​the foundation slab. By summarizing and analyzing the frost heave data of each measuring point in the frost heave layer at different time periods obtained from multiple frozen soil frost heave and thaw settlement deformation monitoring units (30), the process of evaluating the frost heave of the building in the same time period or at the same time point is to summarize the frost heave rate data of all monitoring points obtained in the same time period or at the same time point, draw a three-dimensional image of the plane position of each measuring point and its frost heave deformation rate, and mark the trend of change with time. Through the analysis of the maximum, minimum, average and time-varying laws of frost heave, the frost heave of the frost heave layer in the measurement area is comprehensively evaluated. The planar positions of each measuring point and their frost heave deformation rates are plotted into a three-dimensional image, and the changing trend over time is marked. By analyzing the maximum, minimum, and average values ​​of frost heave and their changing patterns over time, the frost heave condition of the frost heave layer in the measurement area can be comprehensively evaluated. The specific process is as follows: At the same time, frost heave rate data of all monitoring points are obtained, and frost heave deformation diagram of the whole plane is drawn by drawing software. By comparing the maximum, minimum and average values ​​of frost heave, the maximum value and its position are selected and marked. When the frost heave deformation of a localized area monitored at a certain monitoring point in the test area is excessive, exceeding the average frost heave rate of the soil in the region over the past 5 years, an early warning is issued, and the magnitude of the frost heave force generated by the frost heave deformation in this localized area on the foundation beam or foundation slab is calculated. Simultaneously, the trend of frost heave rate over time is plotted. When the frost heave rate of a certain monitoring point consistently exceeds the average, it is placed under close observation, and the magnitude of the frost heave force generated on the foundation beam or foundation slab is calculated to determine whether it will pose a threat to structural stability. The specific calculation method is as follows: Beam calculations: Based on the frost heave deformation of frozen soil, calculate the corresponding frost heave force according to Equation 1-1: （1-1） in: P —Normal frost heave force, in N; ΔH —The frost heave deformation of the frost-susceptible soil layer at the monitoring point, in mm; E —The elastic modulus of frozen soil, in N / mm² 2 μ —Poisson's ratio of frost-susceptible soil layers; —The side length of the monitoring plate, in mm; When the monitoring and early warning method is applied to a building with an independent foundation, the measured vertical displacement of the column is: Δs Then you need to use Δ H - Δs The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated; when the monitoring and early warning method is used for a building foundation that is a pile foundation (41), it is directly used ΔH Calculate the frost heave force; Due to seasonal freeze-thaw cycles, the pore water inside the soil will change between the solid and liquid phases and undergo significant deformation, leading to damage to the building foundation and ground surface. Therefore, during the construction of the building foundation, backfilling or anti-frost heave measures will be taken at the part of the building that is in contact with the frozen soil layer (38). At this time, the middle layer between the foundation beam or foundation slab and the frozen soil layer (38) is a buffer layer. When a buffer layer is present, the amount of frost heave deformation absorbed by the buffer layer is: Δh Then you need to use ΔH-Δh The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated. Based on the obtained frost heave force, and for safety considerations, the largest load is selected as the actual load at a measured point, denoted as Pi. The load distribution is divided into two equivalent uniformly distributed loads on the beam for calculation. When calculating according to elastic theory, the trapezoidal or triangular loads on the beam can be converted into equivalent uniformly distributed loads based on the condition of equal support rotation angles, and then calculated according to structural mechanics methods. For multi-span continuous beams, the support bending moments under the equivalent uniformly distributed loads can be obtained from tables. Then, using the obtained support bending moments and the actual load of each span, the shear force and section bending moment of the beam are obtained according to the equilibrium conditions, so as to determine whether the stress at this time meets the design safety range of the beam. When the actual load distribution is approximated as a triangle, the distribution diagram is equivalent to the uniformly distributed load on the right side for calculation. Let q be the maximum value of the actual load, and q be the equivalent uniformly distributed load. q is calculated according to Equation 1-2. When the actual load distribution is approximated as a trapezoid, if there are multiple load values ​​that are similar, it is equivalent to the uniformly distributed load on the right side for calculation. q represents the maximum actual load, and q represents the equivalent uniformly distributed load. The distance q is the distance from the end point where the load value decreases; q is calculated according to Equation 1-3: （1-2） ， （1-3） By calculating the internal forces, the bending moment envelope diagram of the beam under load is drawn. When the bending moment envelope diagram of the beam is less than 80% of the beam's design bending moment, the beam is considered to be in a safe state. When it is greater than 80% of the beam's design bending moment, an early warning should be issued in time so that relevant remedial measures can be taken. The process of arranging and calculating monitoring points on the beam slab: When the plate is about to fail, the plastic hinge line (24) occurs at the point of maximum bending moment, and the deformation of the plate is concentrated on the plastic hinge line (24). The appearance of the plastic hinge line (24) makes the several plates of the structure become a geometrically variable system. Therefore, the monitoring points are installed on the plastic hinge line (24) of the plate, namely AE, BE, CE, DE, EF. For segment EF, the average deflection of segment EF is calculated according to equation 1-4: （1-4） Where: ν—average deflection; ΔH i —The amount of frost heave deformation in the frost-susceptible soil layer at different monitoring points; n — number of monitoring points; When the monitoring and early warning method is applied to a building with an independent foundation, the measured vertical displacement of the column is: Δs Then you need to use Δ H i - Δs The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated; when the monitoring and early warning method is used for a building foundation that is a pile foundation (41), it is directly used ΔH i Calculate the frost heave force; When a buffer layer is present, the amount of frost heave deformation absorbed by the buffer layer is: Δh Then you need to use ΔH i -Δh The frost heave deformation of the frost-susceptible soil layer at the monitoring point is calculated. Since the slab is surrounded by beams, it can be considered as an equivalent two-way slab with four simply supported segments. For the elastic limit analysis method: the magnitude of the obtained shear force is used to derive the equivalent uniformly distributed load, which is then calculated using formula 1-5. （1-5） The equivalent uniformly distributed load obtained is then calculated according to formula 1-6: （1-6） in: B c —This refers to the bending stiffness of the two-way slab strip section; l ox —Distance of the short side of the board; l oy —Distance along the longer side of the board; 、β M --according to 、 The relative value is determined by a coefficient. To determine whether the stress state at this time meets the design safety range of the plate, when the bending moment envelope of the plate is less than 80% of the design bending moment resisted by the plate, the plate is determined to be in a safe and stable state; when the bending moment envelope of the plate is greater than 80% of the design bending moment resisted by the plate, the plate is determined to be in an unsafe and unstable state, and an early warning should be issued in time so that relevant remedial measures can be taken.

2. The monitoring and early warning method according to claim 1, characterized in that: The process of determining the soil frost heave type based on the average frost heave rate of the soil in the building area is as follows: The average frost heave rate of the soil in the building location over the past 5 years is consulted. Based on the frost heave rate ranges of 0–1%, 1–3.5%, 3.5–6%, 6–10%, and above 10%, the soil is classified into non-frost heave, weakly frost heave, frost heave, strongly frost heave, and extremely strongly frost heave. Frost heave, strongly frost heave, and extremely strongly frost heave all belong to frost heave-sensitive frozen soil, while non-frost heave and weakly frost heave belong to frost heave-insensitive frozen soil. After determining the number and location of frost heave-sensitive and non-frost heave-sensitive frozen soil areas in the building area, corresponding measurement point groups are arranged in the frost heave-sensitive and non-frost heave-sensitive frozen soil areas, along with the number of measurement points in each measurement point group. The density of measurement point arrangement in the frost heave-insensitive frozen soil areas is less than that in the frost heave-sensitive frozen soil areas.

Images