A method and device for assessing the risk of frozen soil thawing and settlement by combining dynamic deformation and static index

Abstract

The present invention provides a method and device for assessing the risk of frozen soil thawing settlement that combines dynamic deformation and static index. The method proposes a risk assessment index that combines the dynamic deformation information of the surface and the static simulation information on the basis of the simulation results of the traditional static risk assessment index. The frozen soil surface deformation information is obtained by interferometric SAR (InSAR) inversion, and the static index simulation results are obtained by the thawing settlement index, the risk zoning index and the allowable bearing capacity index. The static index is combined with the dynamic deformation through the analytic hierarchy process to obtain a multi-factor index that considers the freezing and thawing change state of the frozen soil. The present invention attempts to verify the multi-factor index using the assessment results of the existing index and the frozen soil surface deformation data of the study area, which has a certain reference significance for the assessment of permafrost thawing settlement disasters along the infrastructure in the frozen soil area.

Description

Technical Field

[0001] The present invention relates to the technical field of frozen soil thawing settlement risk assessment, and in particular to a frozen soil thawing settlement risk assessment method and device combining dynamic deformation and static index. Background Art

[0002] As the global climate warms, rising temperatures will accelerate the degradation of permafrost, causing geological disasters such as thawing settlement, landslides, and lake expansion, which have a significant impact on local hydrological and ecological processes, the stability of permafrost engineering, and the global carbon balance. Traditional geodetic methods can monitor permafrost at a point scale, but are limited by human, material, and financial resources at a large scale. Risk mapping is a spatial representation of the risks associated with specific hazards. It is used to determine the current and future risks of a region and can be used to assess the risk of thawing settlement of permafrost on a large scale.

[0003] Nelson et al. (2001) first proposed a thaw settlement index that takes into account the relative changes in the ice content of frozen soil and the thickness of the active layer; Daanen et al. (2012) considered four different factors and proposed a risk zoning index; Xu and Wu (2019) considered the different bearing capacities of different soil types and proposed an allowable bearing capacity index by combining the annual average ground temperature with the soil type. However, these indices all have some shortcomings. For example, the thaw settlement index and the allowable bearing capacity index do not comprehensively consider the factors affecting thaw settlement disasters, and the judgment process of the risk zoning index currently lacks the ability to handle ice separation in sediments, so there may be errors in judging the ice content. In addition, the above-mentioned traditional indices have different results due to the different factors they consider, and most of these indices are static and do not consider the dynamic changes of the freeze-thaw process. Summary of the invention

[0004] How to solve the shortcomings of the above method is the main problem solved by the present invention.

[0005] The technical solution adopted by the present invention is: a method and device for assessing the risk of thawing and settlement of frozen soil combining dynamic deformation and static index are proposed. The method uses InSAR technology to obtain the frozen soil surface deformation, and combines the traditional risk assessment index and the frozen soil surface deformation through the hierarchical analysis method to obtain a multi-factor index, taking into account various frozen soil thawing and settlement disaster factors and the dynamic changes of frozen soil freeze-thaw cycles, so as to improve the accuracy of risk zoning.

[0006] According to one aspect of the present invention, a frozen soil thawing settlement risk assessment method combining dynamic deformation and static index comprises the following steps:

[0007] Obtain three static indices for frozen soil thawing settlement risk assessment, including thawing settlement index, risk zoning index and allowable bearing capacity index;

[0008] Use InSAR technology to obtain frozen ground surface deformation;

[0009] Calculating the correlation coefficients between the frozen ground surface deformation and the three static indices respectively;

[0010] According to the correlation coefficients, a judgment matrix is ​​listed through the hierarchical analysis method to obtain the weights of frozen soil surface deformation and three static indexes. The multi-factor index for frozen soil thawing settlement risk assessment is obtained by superimposing the weights.

[0011] Preferably, the step of obtaining the melting-settling index comprises:

[0012] The annual average ground temperature, slope, normalized difference vegetation index and soil type data were obtained, and the weights of different data were obtained through the hierarchical analysis method, and the volume ice content was obtained by superposition;

[0013] Collect soil type parameter data and local melting index, and use Stefan formula to get the active layer thickness. The calculation formula is as follows:

[0014]

[0015] Among them, Z is the thickness of the active layer; λ is the thermal conductivity of the soil; DDT is the melting index; L is the latent heat of ice melting; γ is the dry bulk density of the soil; W is the total water content of the soil during melting; Wu is the unfrozen water content in the frozen soil;

[0016] According to the thickness of the active layer and the ice content of the frozen soil volume, the thawing settlement index is calculated by the thawing settlement formula, and the calculation formula is as follows:

[0017] I s =V ice ×ΔALT

[0018] Among them, I s is the melting index, V ice is the volumetric ice content of frozen soil, ΔALT is the relative rate of change of the thickness of the active layer;

[0019] The melting-sinking index is classified according to the nested-means method into low-risk area, medium-risk area and high-risk area.

[0020] Preferably, the step of obtaining the risk zoning index comprises:

[0021] For frozen soil areas, determine whether the surface is bare rock or a sedimentary basin. If it is bare rock, it is directly judged as a low-risk area. If it is a sedimentary basin, it is judged to be gravel or sand, or silt or clay.

[0022] If it is gravel or sand, determine the ice content. If the ice content is lower than the preset ice content value, it is determined to be a low-risk area. Otherwise, continue to determine the thickness of the active layer. If the thickness of the active layer is greater than the preset active layer thickness value, it is determined to be a high-risk area. Otherwise, it is determined to be a medium-risk area.

[0023] If it is silt or clay, the ice content is also judged. If the ice content is lower than the preset ice content value, it is judged as a low-risk area; otherwise, continue to judge whether the active layer thickness is greater than the preset active layer thickness value. If so, it is judged as a high-risk area, otherwise it is judged as a medium-risk area.

[0024] Preferably, the step of obtaining the allowable bearing capacity index comprises:

[0025] According to the soil properties of the frozen ground surface, the frozen ground surface is divided into five categories: the first category: crushed gravel soil, the second category: gravel sand and coarse sand, the third category: medium sand, fine sand and silt sand, the fourth category: clay, silty clay and silt soil, and the fifth category: soil-containing ice layer;

[0026] Different soil types correspond to different allowable bearing capacity formulas, as follows:

[0027] Category 1: R f =-0.3959MAGT+0.6092

[0028] Category 2: R f =-0.3012MAGT+0.4954

[0029] Category 3: R f =-0.3012MAGT+0.3454

[0030] Category 4: R f =-0.1979MAGT+0.3046

[0031] Category 5: R f =-0.1MAGT+0.0500

[0032] Among them, R f is the allowable bearing capacity of the frozen ground area, MAGT is the annual mean ground temperature;

[0033] The allowable bearing capacity index is divided into low-risk area, medium-risk area and high-risk area according to the nested-means method.

[0034] Preferably, the step of obtaining frozen ground surface deformation using InSAR technology includes:

[0035] Based on the small baseline set interferometry method, multiple synthetic aperture radar images are interferometrically processed to determine the surface deformation rate of the frozen soil study area.

[0036] Preferably, the correlation coefficients between the frozen ground surface deformation and the three static indices are calculated respectively, and the specific calculation formula is as follows:

[0037]

[0038] Among them, R xy is the correlation coefficient between the two sample variables of surface deformation and any static index, x i ,y i are the surface deformation and any static index, The average value corresponding to the surface deformation and any static index, n is the number of sample variables, and i represents the sequence number of the sample variable.

[0039] Preferably, the step of listing a judgment matrix by means of a hierarchical analysis method according to each correlation coefficient, obtaining weights of frozen ground surface deformation and three static indexes, and obtaining a multi-factor index for frozen ground thawing and settlement risk assessment according to weight superposition includes:

[0040] Based on the correlation coefficients, a judgment matrix about frozen ground surface deformation and three static indices is listed.

[0041] The judgment matrix is ​​tested for consistency. If the consistency ratio is less than 0.1, it meets the requirements. If the consistency ratio is not less than 0.1, the importance of the relationship between the frozen ground surface deformation and the three static indices in the judgment matrix is ​​revised until the requirements are met.

[0042] According to the weights obtained from the judgment matrix, the frozen soil surface deformation and the three static indices are superimposed according to the weights to obtain a multi-factor index, which is used for frozen soil thawing settlement risk assessment.

[0043] The consistency check process is as follows:

[0044]

[0045]

[0046] Among them, CI is the consistency index, λ is the maximum eigenvalue of the judgment matrix, m is the order of the judgment matrix, RI is the random consistency index, and CR is the consistency ratio.

[0047] According to another aspect of the present invention, a frozen soil thawing settlement risk assessment method and device combining dynamic deformation and static index includes the following modules:

[0048] Static index acquisition module, used to obtain three static indexes for frozen soil thawing settlement risk assessment, including thawing settlement index, risk zoning index and allowable bearing capacity index;

[0049] Dynamic deformation acquisition module, used to obtain frozen ground surface deformation using InSAR technology;

[0050] A correlation calculation module, used to calculate the correlation coefficients between the frozen ground surface deformation and the three static indices respectively;

[0051] The multi-factor index acquisition module is used to list the judgment matrix through the hierarchical analysis method according to the correlation coefficients, obtain the weights of the frozen ground surface deformation and the three static indexes, and obtain the multi-factor index for frozen soil thawing settlement risk assessment according to the weight superposition.

[0052] The technical solution provided by the present invention has the following beneficial effects: the present invention combines the traditional static index frozen soil thawing settlement risk assessment method and the deformation data considering the dynamic frozen soil freezing and thawing process through the hierarchical analysis method to obtain a multi-factor index that combines multiple disaster influencing factors, and evaluates the frozen soil thawing settlement risk through the index, thereby improving the accuracy of the frozen soil thawing settlement risk zoning results. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The specific effects of the present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

[0054] Figure 1 It is a flow chart of a frozen soil thawing settlement risk assessment method combining dynamic deformation and static index provided by an embodiment of the present invention;

[0055] Figure 2 It is the risk assessment of frozen soil thawing settlement near the Qinghai-Tibet Railway using the multi-factor index proposed in the embodiment of the present invention;

[0056] Figure 3 It is a structural diagram of a frozen soil thawing settlement risk assessment device combining dynamic deformation and static index provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0058] Embodiment 1:

[0059] refer to Figure 1 This embodiment provides a frozen soil thawing settlement risk assessment method combining dynamic deformation and static index, the method comprising the following steps:

[0060] S1: Obtain three static indices for frozen soil thawing settlement risk assessment, including thawing settlement index, risk zoning index and allowable bearing capacity index;

[0061] In this embodiment, S1 specifically includes:

[0062] S1.1: Obtain data related to the thickness of the active layer and the ice content of the frozen soil volume, and calculate the thaw settlement index using the thaw settlement formula. The specific steps are as follows:

[0063] S1.1.1: Obtain the annual average ground temperature, slope, normalized difference vegetation index and soil type data, obtain the weights of different data through the hierarchical analysis method, and superimpose them to obtain the volume ice content;

[0064] S1.1.2: Collect soil type parameter data and local melting index, and use Stefan's formula to obtain the active layer thickness, which is calculated as follows:

[0065]

[0066] Where Z is the thickness of the active layer (m); λ is the thermal conductivity of the soil (W / (m·℃)); DDT is the melting index; L is the latent heat of ice melting (3.3×10 5 J / kg); γ is the dry bulk density of soil (kg / m 3 ); W is the total water content of the soil during thawing (%); Wu is the unfrozen water content in the frozen soil (%);

[0067] S1.1.3: After obtaining the thickness of the active layer and the ice content of the frozen soil volume, the thaw settlement index is calculated using the thaw settlement formula, which is as follows:

[0068] I s =V ice ×ΔALT

[0069] Among them, I s is the melting index, V ice is the volumetric ice content of frozen soil, ΔALT is the relative rate of change of the thickness of the active layer;

[0070] S1.1.4: The obtained melting-settlement index is classified into low-risk area, medium-risk area and high-risk area according to the nested-means method.

[0071] S1.2: Obtain the data on the distribution of exposed bare rock, soil sedimentation basin types, frozen soil ice content and active layer thickness, and obtain the risk zoning index according to the risk zoning process. The specific steps are as follows:

[0072] S1.2.1: For frozen ground areas, determine whether the surface is bare rock or sedimentary basin. If it is bare rock, it is directly judged as a low-risk area. If it is a sedimentary basin, it is judged to be gravel / sand or silt / clay;

[0073] S1.2.2: If it is gravel or sand, determine the ice content (ice content greater than 20% is high, ice content less than 20% is low). If the ice content is low, directly determine it as a low-risk area. If the ice content is high, continue to determine the thickness of the active layer. If the thickness of the active layer is greater than 2.5 meters, it is determined to be a high-risk area. If the thickness of the active layer is less than 2.5 meters, it is determined to be a medium-risk area.

[0074] S1.2.3: If it is silt or clay, the ice content is also judged. If the ice content is low, it is directly judged as a low-risk area. If the ice content is high and the thickness of the active layer is greater than 2.5 meters, it is judged as a high-risk area, otherwise it is a medium-risk area.

[0075] S1.3: Obtain annual average ground temperature data and soil type classification data, and calculate different types of soil according to the allowable bearing capacity model. The specific steps are as follows:

[0076] S1.3.1: The frozen ground surface is divided into five categories according to its soil properties: Category 1: crushed gravel soil, Category 2: gravel sand and coarse sand, Category 3: medium sand, fine sand and silt sand, Category 4: clay, silty clay and silt soil, Category 5: soil-containing ice layer;

[0077] S1.3.2: Different soil types correspond to different allowable bearing capacity formulas, as follows:

[0078] Category 1: R f =-0.3959MAGT+0.6092

[0079] Category 2: R f =-0.3012MAGT+0.4954

[0080] Category 3: R f =-0.3012MAGT+0.3454

[0081] Category 4: R f =-0.1979MAGT+0.3046

[0082] Category 5: R f =-0.1MAGT+0.0500

[0083] Among them, R f is the allowable bearing capacity of the frozen ground area, MAGT is the annual mean ground temperature;

[0084] S1.3.3: The allowable bearing capacity index is divided into low-risk area, medium-risk area and high-risk area according to the nested-means method.

[0085] In step S1, the melting settlement index and the allowable bearing capacity index are divided into low-risk area, medium-risk area and high-risk area according to the nested-means method, in order to unify them with the risk zoning index and facilitate subsequent calculations.

[0086] S2: Using InSAR technology to obtain frozen ground surface deformation;

[0087] In this embodiment, S2 specifically includes: obtaining Sentinel-1AVV polarization data, and obtaining frozen ground surface deformation based on the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) method. The specific steps are as follows:

[0088] S2.1: dividing a plurality of synthetic aperture radar images into a plurality of small baseline sets based on a spatial baseline threshold and a temporal baseline threshold, wherein the small baseline sets include a plurality of synthetic aperture radar image pairs;

[0089] S2.2: determining a deformation time series of each synthetic aperture radar image pair among a plurality of synthetic aperture radar image pairs based on a least square method;

[0090] S2.3: Based on the singular value decomposition method and deformation time series, the surface deformation amount and deformation rate of the closed mining area within a preset time period are obtained.

[0091] S3: respectively calculating the correlation coefficients between the frozen ground surface deformation and the three static indices;

[0092] In S3, the correlation coefficient is used to analyze the correlation between the frozen ground surface deformation and the three static indices. The specific calculation formula is as follows:

[0093]

[0094] Among them, R xy is the correlation coefficient between the two sample variables of surface deformation and any static index, x i ,y i are the surface deformation and any static index, The average value corresponding to the surface deformation and any static index, n is the number of sample variables, and i represents the sequence number of the sample variable.

[0095] S4: According to the correlation coefficients, a judgment matrix is ​​listed through the hierarchical analysis method to obtain the weights of the frozen ground surface deformation and the three static indexes, and a multi-factor index for frozen soil thawing and settlement risk assessment is obtained by superimposing the weights.

[0096] In this embodiment, step S4 specifically includes:

[0097] S4.1: Based on the obtained correlation coefficients, the three static indices and dynamic surface deformation are assigned values ​​using the scales in Table 1 to construct a judgment matrix:

[0098] Table 11-9 Meaning of the scale method

[0099] Scale meaning 1 Indicates that two factors are equally important. 3 Indicates that one factor is slightly more important than the other factor. 5 Indicates that one factor is significantly more important than the other factor when compared with the other factors. 7 Indicates that one factor is more important than the other. 9 Indicates that one factor is extremely more important than the other factor. 2、4、6、8 The median of the two adjacent judgment values reciprocal If the scale of A compared to B is 3, then B is 1 / 3 compared to A.

[0100] S4.2: Find the eigenvector of the judgment matrix, which is the weight of each index;

[0101] S4.3: Perform consistency check on the judgment matrix. If the consistency ratio is less than 0.1, it meets the requirements. If the consistency ratio is not less than 0.1, the importance of the relationship between the frozen ground surface deformation and the three static indices in the judgment matrix is ​​revised until the requirements are met.

[0102] The steps of consistency check are as follows:

[0103]

[0104]

[0105] Among them, CI is the consistency index, λ is the maximum eigenvalue of the judgment matrix, m is the order of the judgment matrix, RI is the random consistency index, and CR is the consistency ratio.

[0106] S4.4: After passing the consistency test, the frozen ground surface deformation and the three static indices are superimposed according to the weights to obtain a multi-factor index.

[0107] In order to verify the risk assessment effect of the multi-factor index in this embodiment, the multi-factor index is used for the risk assessment of frozen soil thawing settlement near the Qinghai-Tibet Railway. Figure 2 , there are five areas with high-risk concentrations in the figure, namely Tanggula, Beilu River, Tuotuo River, Wudaoliang and Xidatan. In these areas, it is necessary to strengthen protective measures and monitor the thawing and settlement of frozen soil in real time. In addition, in the Anduo to Tanggula section, the multi-factor index of this embodiment is divided into a low-risk area, while the comprehensive index calculated by Ni et al. (2021) divides this section into a high-risk area. Combined with the local deformation data results, the surface change in the Anduo to Tanggula section is mainly frozen soil uplift rather than thawing and settlement. Therefore, it is more reasonable to use the multi-factor index proposed in this embodiment to judge the frozen soil thawing and settlement risk in the Anduo to Tanggula section as a low-risk area.

[0108] Embodiment 2:

[0109] refer to Figure 3 This embodiment provides a frozen soil thawing settlement risk assessment device combining dynamic deformation and static index, and the device includes the following modules:

[0110] Static index acquisition module 1 is used to obtain three static indexes for frozen soil thawing settlement risk assessment, including thawing settlement index, risk zoning index and allowable bearing capacity index;

[0111] Dynamic deformation acquisition module 2, used to obtain frozen ground surface deformation using InSAR technology;

[0112] A correlation calculation module 3 is used to calculate the correlation coefficients between the frozen ground surface deformation and the three static indices respectively;

[0113] The multi-factor index acquisition module 4 is used to list the judgment matrix according to the correlation coefficients through the hierarchical analysis method, obtain the weights of the frozen ground surface deformation and the three static indexes, and obtain the multi-factor index for frozen ground thawing settlement risk assessment according to the weight superposition.

[0114] Each module of the frozen soil thawing and settlement risk assessment device is used to implement each step of the frozen soil thawing and settlement risk assessment method embodiment, and can achieve the same technical effect.

[0115] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0116] The serial numbers of the embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In a unit claim that lists several means, several of these means may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order and these words may be interpreted as identifiers.

[0117] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A frozen soil thawing settlement risk assessment method combining dynamic deformation and static index, characterized in that: The following steps are involved: Obtain three static indices for frozen soil thawing settlement risk assessment, including thawing settlement index, risk zoning index and allowable bearing capacity index; Use InSAR technology to obtain frozen ground surface deformation; Calculating the correlation coefficients between the frozen ground surface deformation and the three static indices respectively; According to the correlation coefficients, a judgment matrix is ​​listed through the hierarchical analysis method to obtain the weights of frozen ground surface deformation and three static indexes, and a multi-factor index for frozen soil thawing and settlement risk assessment is obtained by superposition of the weights; The step of obtaining the melting-settling index includes: The annual average ground temperature, slope, normalized difference vegetation index and soil type data were obtained, and the weights of different data were obtained through the hierarchical analysis method, and the frozen soil volume ice content was obtained by superposition; Collect soil type parameter data and local melting index, and use Stefan formula to get the active layer thickness. The calculation formula is as follows: Among them, Z is the thickness of the active layer; λ is the thermal conductivity of the soil; DDT is the melting index; L is the latent heat of ice melting; γ is the dry bulk density of the soil; W is the total water content of the soil during melting; Wu is the unfrozen water content in the frozen soil; According to the thickness of the active layer and the ice content of the frozen soil volume, the thawing settlement index is calculated by the thawing settlement formula, and the calculation formula is as follows: I s =V ice ×ΔALT Among them, I s is the melting index, V ice is the volumetric ice content of frozen soil, ΔALT is the relative rate of change of the thickness of the active layer; The melting and sinking index is classified into low-risk area, medium-risk area and high-risk area according to the nested-means method; The step of obtaining the risk zoning index comprises: For frozen soil areas, determine whether the surface is bare rock or sedimentary basin. If it is bare rock, it is judged as a low-risk area. If it is a sedimentary basin, continue to determine whether it is gravel or sand, or silt or clay. If it is gravel or sand, determine the ice content. If the ice content is lower than the preset ice content value, it is determined to be a low-risk area. Otherwise, continue to determine the thickness of the active layer. If the thickness of the active layer is greater than the preset active layer thickness value, it is determined to be a high-risk area. Otherwise, it is determined to be a medium-risk area. If it is silt or clay, the ice content is also judged. If the ice content is lower than the preset ice content value, it is judged as a low-risk area; otherwise, it is further judged whether the active layer thickness is greater than the preset active layer thickness value. If so, it is judged as a high-risk area, otherwise it is judged as a medium-risk area; The step of obtaining the allowable bearing capacity index comprises: According to the soil properties of the frozen ground surface, the frozen ground surface is divided into five categories: the first category: crushed gravel soil, the second category: gravel sand and coarse sand, the third category: medium sand, fine sand and silt sand, the fourth category: clay, silty clay and silt soil, and the fifth category: soil-containing ice layer; Different soil types correspond to different allowable bearing capacity formulas, as follows: Category 1: R f =-0.3959MAGT+0.6092 Category 2: R f =-0.3012MAGT+0.4954 Category 3: R f =-0.3012MAGT+0.3454 Category 4: R f =-0.1979MAGT+0.3046 Category 5: R f =-0.1MAGT+0.0500 Among them, R f is the allowable bearing capacity of the frozen ground area, MAGT is the annual mean ground temperature; The allowable bearing capacity index is divided into low-risk area, medium-risk area and high-risk area according to the nested-means method.

2. The frozen soil thawing settlement risk assessment method according to claim 1, characterized in that: The step of obtaining frozen ground surface deformation using InSAR technology includes: Based on the small baseline set interferometry method, multiple synthetic aperture radar images are interferometrically processed to determine the surface deformation rate of the frozen soil study area.

3. The frozen soil thawing settlement risk assessment method according to claim 1 is characterized in that: The correlation coefficients between the frozen ground surface deformation and the three static indices are calculated respectively, and the specific calculation formula is as follows: Among them, R xy is the correlation coefficient between the two sample variables of surface deformation and any static index, x i ,y i are the surface deformation and any static index, The average value corresponding to the surface deformation and any static index, n is the number of sample variables, and i represents the sequence number of the sample variable.

4. The frozen soil thawing settlement risk assessment method according to claim 1 is characterized in that: The steps of listing a judgment matrix by using the hierarchical analysis method according to each correlation coefficient, obtaining the weights of the frozen ground surface deformation and the three static indexes, and obtaining a multi-factor index for frozen ground thawing and settlement risk assessment according to the weight superposition include: Based on the correlation coefficients, a judgment matrix about frozen ground surface deformation and three static indices is listed. The judgment matrix is ​​tested for consistency. If the consistency ratio is less than 0.1, it meets the requirements. If the consistency ratio is not less than 0.1, the importance of the relationship between the frozen ground surface deformation and the three static indices in the judgment matrix is ​​revised until the requirements are met. According to the weights obtained from the judgment matrix, the frozen soil surface deformation and the three static indices are superimposed according to the weights to obtain a multi-factor index, which is used for frozen soil thawing settlement risk assessment.

5. The frozen soil thawing settlement risk assessment method according to claim 4 is characterized in that: The consistency check process is as follows: Among them, CI is the consistency index, λ is the maximum eigenvalue of the judgment matrix, m is the order of the judgment matrix, RI is the random consistency index, and CR is the consistency ratio.

6. A frozen soil thawing settlement risk assessment method and device combining dynamic deformation and static index, characterized in that: Includes the following modules: Static index acquisition module, used to obtain three static indexes for frozen soil thawing settlement risk assessment, including thawing settlement index, risk zoning index and allowable bearing capacity index; Dynamic deformation acquisition module, used to obtain frozen ground surface deformation using InSAR technology; A correlation calculation module, used to calculate the correlation coefficients between the frozen ground surface deformation and the three static indices respectively; A multi-factor index acquisition module is used to list a judgment matrix according to each of the correlation coefficients through a hierarchical analysis method to obtain the weights of frozen ground surface deformation and three static indexes, and obtain a multi-factor index for frozen ground thawing and settlement risk assessment according to the weight superposition; The step of obtaining the melting-settling index includes: The annual average ground temperature, slope, normalized difference vegetation index and soil type data were obtained, and the weights of different data were obtained through the hierarchical analysis method, and the frozen soil volume ice content was obtained by superposition; Collect soil type parameter data and local melting index, and use Stefan formula to get the active layer thickness. The calculation formula is as follows: Among them, Z is the thickness of the active layer; λ is the thermal conductivity of the soil; DDT is the melting index; L is the latent heat of ice melting; γ is the dry bulk density of the soil; W is the total water content of the soil during melting; Wu is the unfrozen water content in the frozen soil; According to the thickness of the active layer and the ice content of the frozen soil volume, the thawing settlement index is calculated by the thawing settlement formula, and the calculation formula is as follows: I s =V ice ×ΔALT Among them, I s is the melting index, V ice is the volumetric ice content of frozen soil, ΔALT is the relative rate of change of the thickness of the active layer; The melting and sinking index is classified into low-risk area, medium-risk area and high-risk area according to the nested-means method; The step of obtaining the risk zoning index comprises: For frozen soil areas, determine whether the surface is bare rock or sedimentary basin. If it is bare rock, it is judged as a low-risk area. If it is a sedimentary basin, continue to determine whether it is gravel or sand, or silt or clay. If it is gravel or sand, determine the ice content. If the ice content is lower than the preset ice content value, it is determined to be a low-risk area. Otherwise, continue to determine the thickness of the active layer. If the thickness of the active layer is greater than the preset active layer thickness value, it is determined to be a high-risk area. Otherwise, it is determined to be a medium-risk area. If it is silt or clay, the ice content is also judged. If the ice content is lower than the preset ice content value, it is judged as a low-risk area; otherwise, it is further judged whether the active layer thickness is greater than the preset active layer thickness value. If so, it is judged as a high-risk area, otherwise it is judged as a medium-risk area; The step of obtaining the allowable bearing capacity index comprises: According to the soil properties of the frozen ground surface, the frozen ground surface is divided into five categories: the first category: crushed gravel soil, the second category: gravel sand and coarse sand, the third category: medium sand, fine sand and silt sand, the fourth category: clay, silty clay and silt soil, and the fifth category: soil-containing ice layer; Different soil types correspond to different allowable bearing capacity formulas, as follows: Category 1: R f =-0.3959MAGT+0.6092 Category 2: R f =-0.3012MAGT+0.4954 Category 3: R f =-0.3012MAGT+0.3454 Category 4: R f =-0.1979MAGT+0.3046 Category 5: R f =-0.1MAGT+0.0500 Among them, R f is the allowable bearing capacity of the frozen ground area, MAGT is the annual mean ground temperature; The allowable bearing capacity index is divided into low-risk area, medium-risk area and high-risk area according to the nested-means method.

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