Method and device for acquiring thickness of permafrost, storage medium and equipment

Abstract

The invention provides a permafrost layer thickness obtaining method and device, a storage medium and equipment, and the method comprises the steps: obtaining the environment similarity between a to-be-predicted point and each reference hole according to an environment feature vector, the environment feature vector comprises a plurality of key environment factors, and the to-be-predicted point and each reference hole are located in a permafrost region; according to the fitting temperature function of the target reference hole and the target offset, the fitting temperature function of the to-be-predicted point is determined, the target reference hole is a reference hole having the highest environmental similarity with the to-be-predicted point, and the target offset is the temperature difference between the to-be-predicted point and the target reference hole at the first preset depth; and determining the permafrost layer thickness of the to-be-predicted point according to the fitting temperature function of the to-be-predicted point. A small amount of deep drill hole ground temperature profile data is used as a reference, the thickness of the permafrost of the wide shallow drill holes in the area is estimated, and the thickness of a permafrost layer of a to-be-predicted point is rapidly and accurately obtained.

Description

Technical Field

[0001] The present invention relates to the field of monitoring, and in particular, to a method, device, storage medium and equipment for obtaining the thickness of permafrost layers. Background Art

[0002] Permafrost refers to the rock and soil layer with a temperature below 0°C at a certain depth below the surface and a duration of two years or more. Permafrost is the product of a cold climate and is a common geological structure in cold regions. According to statistics, about 25% of the global land area is developed with permafrost, and permafrost is closely related to human production and life in cold regions. In the past century, the global climate has been experiencing changes characterized by warming. Correspondingly, permafrost, as an important part of the cryosphere, is degrading, mainly manifested as the thickening of the active layer, the increase in ground temperature, the thinning of the thickness, and the reduction of the area, etc.

[0003] The thickness of permafrost is an important indicator for measuring the development and degradation status of permafrost. Understanding the distribution law of permafrost thickness is of great significance for understanding the development characteristics of permafrost, regional distribution, natural environment assessment of permafrost areas, and engineering construction. The thickness of permafrost refers to the thickness of the frozen rock / soil layer between the upper limit and the lower limit of permafrost. The rock and soil layer covered by the upper part of the permafrost layer, which freezes in winter and thaws in summer, is called the active layer. The lower limit of permafrost refers to the lower interface of permafrost in the vertical section, also known as the permafrost floor, measured by depth. On the ground temperature curve, it usually shows the interface where the ground temperature at the bottom of the permafrost layer is 0°C. Above it is permafrost, and below it is unfrozen soil. The thickness of the active layer changes with the changes in climate, soil moisture and soil texture. For example, in the Arctic region, the thickness of the active layer is only a few tens of centimeters, and the thickness of the active layer in the permafrost area of the Qinghai-Tibet Plateau varies from 1 to 3 m, accounting for a relatively small proportion of the permafrost thickness. Therefore, in field surveys, the depth of the lower limit of permafrost is usually approximated as the thickness of permafrost. The main purpose of permafrost thickness investigation is to obtain the depth and spatial distribution of the lower limit of permafrost.

[0004] Permafrost is a unique geological structure formed in cold regions. Current research on permafrost mainly focuses on the active layer and the near surface. In fact, the thickness of permafrost can generally reach dozens to hundreds of meters, and the maximum recorded permafrost thickness in the Northern Hemisphere can reach 1400 m. Due to technical and cost limitations, the number of boreholes that can penetrate the permafrost layer is scarce in scientific research and engineering surveys, and the understanding of the deep permafrost structure and permafrost thickness is far from sufficient. The existence of deep permafrost has an important impact on the hydrological cycle process, and the thickness of permafrost affects the occurrence state and migration law of deep groundwater. At the same time, permafrost is the basal layer of some cold-region ecosystems. The thinning and disappearance of the permafrost thickness will significantly change the ecosystem. In addition, soil profiles in recent decades have recorded hydrological changes caused by permafrost degradation and thickness disappearance, such as the increase in winter base flow and thermokarst lakes. In engineering, the thinning of permafrost thickness will weaken and damage the bearing capacity of the foundation and affect the safety of infrastructure. The permafrost thickness is also an important calculation parameter for evaluating the underground ice storage and carbon storage in permafrost.

[0005] It is not difficult to understand that the greater the drilling depth, the more accurate the calculated permafrost thickness will be, but the corresponding technical requirements and implementation costs will increase significantly. Therefore, at present, scholars and engineers in related fields mostly adopt a compromise method, controlling the borehole depth within the range of 10 - 20 m. How to infer the thermal condition of deep permafrost and then quantify the permafrost thickness using the limited number of shallow borehole ground temperature observation data has become a key problem that permafrost scientists and engineers urgently need to solve. Summary of the Invention

[0006] The purpose of the present invention is to provide a method, device, storage medium and equipment for obtaining the permafrost layer thickness to improve the above problems.

[0007] To achieve the above purpose, the technical solutions adopted in the embodiments of the present invention are as follows:

[0008] In a first aspect, an embodiment of the present invention provides a method for obtaining the permafrost layer thickness, the method comprising:

[0009] According to the environmental feature vector, obtain the environmental similarity between the point to be predicted and each reference borehole, wherein the environmental feature vector includes a plurality of key environmental factors, and the point to be predicted and each reference borehole are both in the permafrost region;

[0010] According to the fitting temperature function of the target reference borehole and the target offset, determine the fitting temperature function of the point to be predicted, wherein the target reference borehole is the reference borehole with the highest environmental similarity to the point to be predicted, and the target offset is the temperature difference between the point to be predicted and the target reference borehole at the first preset depth;

[0011] Determine the thickness of the permafrost layer at the point to be predicted according to the fitted temperature function of the point to be predicted.

[0012] Optionally, the determining the thickness of the permafrost layer at the point to be predicted according to the fitted temperature function of the point to be predicted includes:

[0013] Substitute 0°C into the fitted temperature function of the point to be predicted to determine the lower limit of the permafrost layer;

[0014] Determine the thickness of the permafrost layer according to the lower limit and the upper limit of the permafrost layer.

[0015] Optionally, the obtaining the environmental similarity between the point to be predicted and each reference hole according to the environmental feature vector includes:

[0016] Determine the environmental distance between the point to be predicted and the reference hole according to the environmental feature vector of the point to be predicted and the environmental feature vector of the reference hole;

[0017] Use the exponential function to convert the environmental distance into the environmental similarity between the point to be predicted and the reference hole.

[0018] Optionally, the method further includes: determining the nth geothermal gradient function corresponding to the reference hole according to the nth set of stable geothermal parameter combinations and the set of instantaneous geothermal gradients corresponding to the reference hole, where the stable geothermal parameter combination includes the stable geothermal gradient depth and the stable geothermal gradient, and the set of instantaneous geothermal gradients includes the instantaneous geothermal gradients at each monitoring depth after the first preset depth of the reference hole, 1 ≤ n ≤ N, and N represents the total number of sets of stable geothermal parameter combinations;

[0019] Determine the nth initial fitted temperature function corresponding to the reference hole according to the nth geothermal gradient function corresponding to the reference hole;

[0020] Obtain the evaluation index between the nth initial fitted temperature function corresponding to the reference hole and the measured temperature function of the reference hole, where the evaluation index includes the coefficient of determination and / or the root mean square error;

[0021] Determine the fitted temperature function corresponding to the reference hole from the N initial fitted temperature functions according to the evaluation index.

[0022] Optionally,

[0023] where GOT(Z) n represents the nth geothermal gradient function, a n represents the first fitting parameter in the nth geothermal gradient function, Z represents the depth, b nRepresents the second fitting parameter in the nth geothermal gradient function, H n Represents the geothermal gradient depth in the nth set of stable geothermal parameter combinations, C n Represents the stable geothermal gradient in the nth set of stable geothermal parameter combinations, T(Z) n Represents the nth initial fitting temperature function, C 1 and C 2 are constants.

[0024] Optionally, before determining the nth geothermal gradient function corresponding to the reference borehole according to the nth set of stable geothermal parameter combinations and the set of instantaneous geothermal gradients corresponding to the reference borehole, the method further includes:

[0025] Performing interpolation processing based on the geothermal measurement values at different measurement depths of the borehole to obtain the estimated geothermal values corresponding to each target depth between any two adjacent measurement depths;

[0026] Determining the instantaneous geothermal gradients at each monitoring depth after the first preset depth of the first type of borehole according to the geothermal measurement values at different measurement depths of the first type of borehole and the estimated geothermal values corresponding to each target depth, where the monitoring depth is the measurement depth or the target depth, and the first type of borehole is a borehole with a depth greater than the second preset depth;

[0027] Determining the first type of borehole with a positive gradient for the instantaneous geothermal gradient after the first preset depth as the reference borehole.

[0028] Optionally, the determining the instantaneous geothermal gradients at each monitoring depth after the first preset depth of the first type of borehole according to the geothermal measurement values at different measurement depths of the first type of borehole and the estimated geothermal values corresponding to each target depth includes:

[0029] Obtaining the geothermal values at each monitoring depth within the target window;

[0030] where the target window is a window centered on the target monitoring depth and with a length of a preset length;

[0031] Determining the geothermal change rate within the target window based on the geothermal values at each monitoring depth within the target window as the instantaneous geothermal gradient corresponding to the target monitoring depth.

[0032] In a second aspect, an embodiment of the present invention provides a device for obtaining the thickness of a permafrost layer, the device including:

[0033] A first processing unit, configured to obtain the environmental similarity between the point to be predicted and each reference borehole according to the environmental feature vector, where the environmental feature vector includes multiple key environmental factors, and the point to be predicted and each reference borehole are both in a permafrost region;

[0034] The first processing unit is further configured to determine the fitted temperature function of the point to be predicted according to the fitted temperature function of the target reference hole and the target offset, where the target reference hole is the reference hole with the highest environmental similarity to the point to be predicted, and the target offset is the temperature difference between the point to be predicted and the target reference hole at the first preset depth;

[0035] The second processing unit is configured to determine the permafrost layer thickness of the point to be predicted according to the fitted temperature function of the point to be predicted.

[0036] In a third aspect, an embodiment of the present invention provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the above method is implemented.

[0037] In a fourth aspect, an embodiment of the present invention provides an electronic device, where the electronic device includes: a processor and a memory, and the memory is used to store one or more programs; when the one or more programs are executed by the processor, the above method is implemented.

[0038] Compared with the prior art, a method, device, storage medium and equipment for obtaining permafrost layer thickness provided by an embodiment of the present invention obtain the environmental similarity between a point to be predicted and each reference hole according to an environmental feature vector, where the environmental feature vector includes multiple key environmental factors, and both the point to be predicted and each reference hole are in a permafrost area; determine the fitted temperature function of the point to be predicted according to the fitted temperature function of the target reference hole and the target offset, where the target reference hole is the reference hole with the highest environmental similarity to the point to be predicted, and the target offset is the temperature difference between the point to be predicted and the target reference hole at the first preset depth; determine the permafrost layer thickness of the point to be predicted according to the fitted temperature function of the point to be predicted. Using a small amount of deep borehole ground temperature profile data as a reference, the permafrost thickness of a large number of shallow boreholes in the area is estimated, and the permafrost layer thickness of the point to be predicted is obtained quickly and accurately.

[0039] To make the above objects, features and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given, and in conjunction with the accompanying drawings, the detailed description is as follows. Description of the Drawings

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained according to these drawings without creative efforts.

[0041] Figure 1Schematic structural diagram of the electronic device provided by the embodiment of the present invention.

[0042] Figure 2 One of the flow schematic diagrams of the method for obtaining the thickness of permafrost provided by the embodiment of the present invention.

[0043] Figure 3 Another flow schematic diagram of the method for obtaining the thickness of permafrost provided by the embodiment of the present invention.

[0044] Figure 4 The third flow schematic diagram of the method for obtaining the thickness of permafrost provided by the embodiment of the present invention.

[0045] Figure 5 Unit schematic diagram of the device for obtaining the thickness of permafrost provided by the embodiment of the present invention.

[0046] In the figure: 10 - processor; 11 - memory; 12 - bus; 13 - communication interface; 501 - first processing unit; 502 - second processing unit. Detailed implementation manners

[0047] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0048] Therefore, the detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0049] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present invention, terms such as "first" and "second" are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0050] It should be noted that, in this text, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0051] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0052] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "arrange" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] The following will, with reference to the drawings, elaborate on some embodiments of the present invention. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0054] The embodiment of the present invention provides a method for obtaining the thickness of permafrost layers. By using a small amount of deep borehole geothermal profile data as a reference, the estimation of the thickness of permafrost in a large area of shallow boreholes is realized. The methods and processes involved can provide service support for hydrogeological research in cold regions, exploration of permafrost characteristics, and guidance for infrastructure construction in cold regions.

[0055] The embodiment of the present invention provides an electronic device, which can be a mobile phone device, a computer device, a server device, etc. Please refer to Figure 1, a schematic diagram of the structure of an electronic device. The electronic device includes a processor 10, a memory 11, and a bus 12. The processor 10 and the memory 11 are connected via the bus 12, and the processor 10 is used to execute an executable module stored in the memory 11, such as a computer program.

[0056] The processor 10 may be an integrated circuit chip having signal processing capability. In the implementation process, each step of the method for obtaining the thickness of the permafrost layer may be completed by an integrated logic circuit of hardware in the processor 10 or by instructions in the form of software. The above-mentioned processor 10 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, or discrete hardware components.

[0057] The memory 11 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory.

[0058] The bus 12 may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus. Figure 1 Although only one bidirectional arrow is used in the figure, it does not mean that there is only one bus 12 or only one type of bus 12 .

[0059] The memory 11 is used to store programs, such as programs corresponding to the permafrost layer thickness acquisition device. The permafrost layer thickness acquisition device includes at least one software function module that can be stored in the memory 11 in the form of software or firmware or solidified in the operating system (OS) of the electronic device. After receiving the execution instruction, the processor 10 executes the program to implement the permafrost layer thickness acquisition method.

[0060] Possibly, the electronic device provided by an embodiment of the present invention further includes a communication interface 13. The communication interface 13 is connected to the processor 10 through a bus.

[0061] It should be understood that Figure 1 the structure shown is only a schematic diagram of part of the structure of the electronic device, and the electronic device may further include more or fewer components than those shown Figure 1 herein, or have a different configuration from that shown Figure 1 herein. Figure 1 Each component shown herein may be implemented by hardware, software, or a combination thereof.

[0062] A method for obtaining the thickness of permafrost layers provided by an embodiment of the present invention can be, but is not limited to, applied to Figure 1 the electronic device shown herein. For the specific process, please refer to Figure 2 , and the method for obtaining the thickness of permafrost layers includes: S21, S22, and S23, which are specifically described as follows.

[0063] S21. According to the environmental feature vector, obtain the environmental similarity between the point to be predicted and each reference hole.

[0064] Among them, the environmental feature vector includes multiple key environmental factors, and both the point to be predicted and each reference hole are located in the permafrost region. Both the point to be predicted and each reference hole are located in the exploration area, that is, the exploration area is the permafrost region. Optionally, the environmental feature vector includes meteorological factors (temperature factor, precipitation factor, freeze-thaw index factor), soil factors (soil texture factor, land cover factor, bedrock depth factor), and topographic factors (longitude factor, latitude factor, elevation factor, aspect factor, and slope factor), etc. The key environmental factors are the main environmental variables affecting the permafrost condition in the exploration area.

[0065] Optionally, S21. According to the environmental feature vector, obtain the environmental similarity between the point to be predicted and each reference hole, including: S211 and S212, specifically as follows.

[0066] S211. Determine the environmental distance between the point to be predicted and the reference hole according to the environmental feature vector of the point to be predicted and the environmental feature vector of the reference hole.

[0067] S212. Use the exponential function to convert the environmental distance into the environmental similarity between the point to be predicted and the reference hole.

[0068] Regarding the formulas for environmental distance and environmental similarity, an optional implementation manner is also provided in an embodiment of the present invention. Please refer to the following text.

[0069] e i =(EV i,1 ,EV i,2 ,...EVi,K )

[0070] e j = (EV j,1 , EV j,2 ,... EV j,K )

[0071]

[0072] wherein, e i represents the environmental feature vector of the point to be predicted, and e j represents the environmental feature vector of the reference hole. EV i,k represents the k-th key environmental factor in e i , and EV j,k represents the k-th key environmental factor in e j . d i,j represents the environmental distance between the point to be predicted and the reference hole, and K represents the total number of key environmental factors in the environmental feature vector;

[0073] s i,j = exp(-d i,j )

[0074] wherein, s i,j represents the environmental similarity between the point to be predicted and the reference hole. The exponential function is used to convert the environmental distance between the point to be predicted and the reference hole into environmental similarity (0 < d i,j < 1).

[0075] S22. According to the fitting temperature function of the target reference hole and the target offset, determine the fitting temperature function of the point to be predicted.

[0076] wherein, the target reference hole is the reference hole with the highest environmental similarity to the point to be predicted, the target offset is the temperature difference between the point to be predicted and the target reference hole at the first preset depth, and the first preset depth can be the annual change depth corresponding to the exploration area.

[0077] In an optional implementation manner, translate the fitting temperature function of the target reference hole based on the target offset, so as to determine the fitting temperature function of the point to be predicted.

[0078] S23. Determine the permafrost thickness of the point to be predicted according to the fitting temperature function of the point to be predicted.

[0079] Optionally, S23. Determining the permafrost thickness of the point to be predicted according to the fitting temperature function of the point to be predicted includes: S231 and S232, which are specifically described as follows.

[0080] S231. Substitute 0 °C into the fitting temperature function of the point to be predicted to determine the lower limit of the permafrost layer.

[0081] It should be understood that with the increase of depth, under the influence of geothermal heat flow, the ground temperature will gradually increase. When its temperature is greater than 0 °C, it means that it is no longer a frozen soil layer. Therefore, 0 °C is substituted into the fitting temperature function of the point to be predicted to determine the lower limit of the permafrost layer.

[0082] S232. Determine the thickness of the permafrost layer according to the lower limit and upper limit of the permafrost layer.

[0083] Optionally, the formula for the thickness of the permafrost layer is: H = H m -H t ; where H is the thickness of the permafrost layer (m); H m is the lower limit of the permafrost (m); H t is the upper limit of the permafrost (m).

[0084] In an alternative embodiment, the active layer is regarded as a part of the permafrost layer, and the formula for the thickness of the permafrost layer is: H≈H m .

[0085] The embodiment of the present invention provides a method for obtaining the thickness of the permafrost layer. By using a small amount of geothermal temperature profile data of deep boreholes as a reference, the thickness of the permafrost layer of a large number of shallow boreholes in the region can be estimated, and the thickness of the permafrost layer at the point to be predicted can be obtained quickly and accurately.

[0086] On the basis of the foregoing, with regard to how to obtain the fitting temperature function corresponding to the reference hole, the embodiment of the present invention also provides an alternative embodiment. Please refer to Figure 3 , the method for obtaining the thickness of the annual frozen soil layer further includes: S14, S15, S16, and S17, which are specifically described as follows.

[0087] S14. Determine the nth geothermal gradient function corresponding to the reference hole according to the nth set of stable geothermal parameter combinations and the set of instantaneous geothermal gradients corresponding to the reference hole.

[0088] Among them, the stable geothermal parameter combination includes the stable geothermal gradient depth and the stable geothermal gradient. The set of instantaneous geothermal gradients includes the instantaneous geothermal gradients at each monitoring depth after the first preset depth of the reference hole. 1≤n≤N, and N represents the total number of sets of stable geothermal parameter combinations.

[0089] Optionally, the formula for the nth geothermal gradient function is:

[0090]

[0091] where GOT(Z) n represents the nth geothermal gradient function, a n represents the first fitting parameter in the nth geothermal gradient function, Z represents the depth, b nRepresents the second fitting parameter in the nth geothermal gradient function, H n Represents the geothermal gradient depth in the nth set of stable geothermal parameter combinations, C n Represents the stable geothermal gradient in the nth set of stable geothermal parameter combinations.

[0092] In an alternative embodiment, a parameter space of two parameters (H, C) can be constructed, and the value ranges of H and C are determined based on empirical knowledge.

[0093] Among them, {H ∈ (15, 16, 17... 38, 39, 40), C ∈ (0.1, 0.11, 0.12... 0.48, 0.49, 0.5)}.

[0094] Taking this as an example, the first set of stable geothermal parameter combinations is (H = 15, C = 0.1), the second set of stable geothermal parameter combinations is (H = 15, C = 0.2), and so on, (H = 15, C = 0.5), (H = 16, C = 0.1), ……, (H = 16, C = 0.5), …… (H = 40, C = 0.1), ……, (H = 40, C = 0.5).

[0095] It should be noted that the geothermal gradient is not a fixed constant at different depths, but a function that varies dynamically with depth. Usually in the shallower soil layer, due to seasonal temperature fluctuations and changes in surface climate conditions, the geothermal gradient may vary with seasons; while in the deep strata, since the geothermal change tends to be slow, the geothermal gradient will gradually tend to be stable, and based on this, a geothermal gradient function can be designed.

[0096] The specific design and assumptions are as follows: In the shallower soil layer, the geothermal gradient may be affected by factors such as seasonal changes and day-night temperature differences, so it cannot be simply considered as a constant. The change of the geothermal gradient with depth can be described by a decay function. As the depth increases, the geothermal gradient may tend to be stable. This usually occurs below the frozen soil layer or under the influence of geothermal flow, where the heat conduction of the soil plays a dominant role. That is, below a certain depth, the geothermal gradient tends to be a constant, which can be modeled by introducing a piecewise function, specifically as the above formula.

[0097] S15. Determine the nth initial fitting temperature function corresponding to the reference hole according to the nth geothermal gradient function corresponding to the reference hole.

[0098] Optionally, the formula of the nth initial fitting temperature function is:

[0099]

[0100] Among them, T(Z) n Represents the nth initial fitting temperature function, C 1 and C2 is a constant.

[0101] S16. Obtain the evaluation index between the n-th order fitting temperature function corresponding to the reference hole and the measured temperature function of the reference hole.

[0102] Among them, the evaluation index includes the coefficient of determination (R 2 ) and / or the root mean square error (RMSE); the measured temperature function is a function constructed based on the measured temperature of the reference hole.

[0103] S17. Determine the fitting temperature function corresponding to the reference hole from the N order fitting temperature functions according to the evaluation index.

[0104] In an alternative embodiment, from one or more order fitting temperature functions with the smallest difference between the coefficient of determination (R 2 ) and 1, determine the order fitting temperature function with the smallest root mean square error (RMSE) as the fitting temperature function corresponding to the reference hole.

[0105] Alternatively, use the order fitting temperature functions with the difference between the coefficient of determination (R 2 ) and 1 less than the preset difference and the root mean square error (RMSE) less than the preset error as the fitting temperature function corresponding to the reference hole.

[0106] Please refer to Table 1. Table 1 is a schematic illustration of the geothermal gradient function corresponding to the fitting temperature function determined based on the embodiments of the present invention.

[0107] Table 1

[0108]

[0109] The Z in Table 1 is all greater than the first preset depth. Five reference holes are taken as examples in Table 1, namely the GHMS borehole, the GH4 borehole, the NJY borehole, the JB-B-I borehole, and the XA-B-I borehole. It can be seen from Table 1 that the geothermal gradient functions corresponding to different reference holes are not the same.

[0110] In an alternative embodiment, after determining the fitting temperature function corresponding to the reference hole, the thickness of the frozen soil layer can be inversely estimated based on it, so as to evaluate the accuracy of the fitting temperature function corresponding to the reference hole. Specifically, please refer to Table 2.

[0111] Table 2

[0112]

[0113] It can be seen from Table 2 that the error of the fitting temperature function corresponding to the reference hole determined based on the embodiments of the present invention is small and the accuracy is high enough.

[0114] InFigure 3 Based on this, regarding how to determine the reference hole, an alternative implementation manner is provided in an embodiment of the present invention. Please refer to Figure 4 , in S14, before determining the nth geothermal gradient function corresponding to the reference hole according to the stable geothermal parameter combination of the nth group and the set of instantaneous geothermal gradients corresponding to the reference hole, the method for obtaining the permafrost layer thickness further includes: S11, S12, and S13, which are specifically described as follows.

[0115] S11, perform interpolation processing (which can be linear interpolation processing or cubic spline interpolation processing) based on the geothermal measurement values at different measurement depths of the borehole to obtain the estimated geothermal values corresponding to each target depth between any two adjacent measurement depths.

[0116] Among them, the interpolation processing can be linear interpolation processing or cubic spline interpolation processing. The interval between any two adjacent target depths is a preset interval length. The interval between the first target depth and the smaller one of the two adjacent measurement depths is the preset interval length, and the interval between the last target depth and the larger one of the two adjacent measurement depths is the preset interval length.

[0117] S12, determine the instantaneous geothermal gradients at each monitoring depth after the first preset depth of the first type of borehole based on the geothermal measurement values at different measurement depths of the first type of borehole and the estimated geothermal values corresponding to each target depth.

[0118] Among them, the monitoring depth is the measurement depth or the target depth. The first type of borehole is a borehole with a depth greater than the second preset depth. The second preset depth is greater than the first preset depth. The first preset depth can be but is not limited to 15m, and the second preset depth can be but is not limited to 25m.

[0119] S13, determine the first type of borehole with a positive gradient of the instantaneous geothermal gradient after the first preset depth as the reference hole.

[0120] Among them, the positive gradient means that after the first preset depth (such as 15m) of the borehole, the temperature rises as the depth increases. When the geothermal gradient of the borehole is a zero gradient or even a negative gradient, the deep geothermal condition cannot be estimated.

[0121] In Figure 4 Based on this, regarding the content in S12, an alternative implementation manner is provided in an embodiment of the present invention. Please refer to the following text. S12, determine the instantaneous geothermal gradients at each monitoring depth after the first preset depth of the first type of borehole based on the geothermal measurement values at different measurement depths of the first type of borehole and the estimated geothermal values corresponding to each target depth, including: S121 and S122, as follows.

[0122] S121. Obtain the ground temperature values at various monitoring depths within the target window.

[0123] Among them, the target window is a window centered on the target monitoring depth (greater than the first preset depth) with a length of the preset length. It should be noted that when the monitoring depth is the measured depth, the ground temperature value at the monitoring depth is the measured ground temperature value at the measured depth; when the monitoring depth is the target depth, the ground temperature value at the monitoring depth is the estimated ground temperature value corresponding to the target depth.

[0124] S122. Determine the ground temperature change rate within the target window based on the ground temperature values at various monitoring depths within the target window, and use it as the instantaneous ground temperature gradient at the corresponding target monitoring depth.

[0125] In an alternative embodiment, regarding how to find the optimal value of the preset length, the embodiment of the present invention also provides an alternative embodiment. Set multiple window estimation lengths. Based on each window estimation length, execute S12 once, so as to obtain the instantaneous ground temperature gradients at various monitoring depths of the first type of borehole under different window estimation lengths. Then, determine the window estimation length whose proportion of jump values below the first preset depth exceeds the target proportion as the final preset length. The jump value herein represents the inflection point of the ground temperature gradient change.

[0126] In some exploration submissions, it can be found through the above steps that when the preset length is 5 m or 7 m, the instantaneous ground temperature gradient at the monitoring depth is still unstable, while when the preset length is 9 m, the instantaneous ground temperature gradient at the monitoring depth reaches a stable state. Therefore, the preset length can be taken as 9 m.

[0127] The information on the thickness of permafrost is an important basic data in the fields of cold region engineering construction, hydrogeological and water resources investigation, ecological environment protection, etc. at present. However, the current borehole ground temperature observations in permafrost regions show that due to the widespread existence of negative ground temperature gradients and zero ground temperature gradients at the annual change depth, the simple ground temperature gradient method has poor general applicability for estimating the thickness of permafrost in many permafrost regions. A method for obtaining the thickness of permafrost layers provided by the embodiment of the present invention constructs a new ground temperature gradient model using the ground temperature profile of reference deep holes in the region; environmental factors that can affect the ground temperature gradient are mapped to shallow holes according to certain rules for the ground temperature gradient model of the reference boreholes; the measured temperature results of the shallow holes are used to iteratively calculate the ground temperature of the deep layer; finally, the corresponding permafrost thickness is obtained by interpolation through the reconstructed deep ground temperature. It improves the prediction accuracy of the engineering geological stability of permafrost, directly serves the planning and construction of cold region infrastructure, and also provides new ideas for regional related basic scientific research.

[0128] Please refer to Figure 5 , Figure 5A device for obtaining the thickness of permafrost layers provided by an embodiment of the present invention. Optionally, the device for obtaining the thickness of permafrost layers is applied to the electronic device described above.

[0129] The device for obtaining the thickness of permafrost layers includes: a first processing unit 501 and a second processing unit 502.

[0130] The first processing unit 501 is configured to obtain the environmental similarity degree between the point to be predicted and each reference hole according to the environmental feature vector, where the environmental feature vector includes a plurality of key environmental factors, and the point to be predicted and each reference hole are both in the permafrost region;

[0131] The first processing unit 501 is further configured to determine the fitting temperature function of the point to be predicted according to the fitting temperature function of the target reference hole and the target offset, where the target reference hole is the reference hole with the highest environmental similarity degree to the point to be predicted, and the target offset is the temperature difference between the point to be predicted and the target reference hole at the first preset depth;

[0132] The second processing unit 502 is configured to determine the thickness of the permafrost layer at the point to be predicted according to the fitting temperature function of the point to be predicted.

[0133] Optionally, the second processing unit 502 may execute the above S23, and the first processing unit 501 may execute other steps in the above method embodiment.

[0134] It should be noted that the device for obtaining the thickness of permafrost layers provided in this embodiment can execute the method flow shown in the above method flow embodiment to achieve the corresponding technical effect. For a brief description, for the parts not mentioned in this embodiment, reference may be made to the corresponding content in the above embodiment.

[0135] An embodiment of the present invention further provides a storage medium, which stores computer instructions and programs. When the computer instructions and programs are read and run, they execute the method for obtaining the thickness of permafrost layers in the above embodiment. The storage medium may include memory, flash memory, registers or a combination thereof, etc.

[0136] The following provides an electronic device, which may be a mobile phone device, a computer device, a server device, etc. As shown in Figure 1 The electronic device can implement the above method for obtaining the thickness of permafrost layers; specifically, the electronic device includes: a processor 10, a memory 11, and a bus 12. The processor 10 may be a CPU. The memory 11 is used to store one or more programs. When the one or more programs are executed by the processor 10, the method for obtaining the thickness of permafrost layers in the above embodiment is executed.

[0137] In summary, a method, device, storage medium and equipment for obtaining the thickness of permafrost layers provided by the embodiments of the present invention obtain the environmental similarity between a point to be predicted and each reference hole according to an environmental feature vector, where the environmental feature vector includes multiple key environmental factors, and the point to be predicted and each reference hole are both in the permafrost region; determine the fitting temperature function of the point to be predicted according to the fitting temperature function of the target reference hole and the target offset, where the target reference hole is the reference hole with the highest environmental similarity to the point to be predicted, and the target offset is the temperature difference between the point to be predicted and the target reference hole at a first preset depth; determine the thickness of the permafrost layer at the point to be predicted according to the fitting temperature function of the point to be predicted. Using a small amount of deep borehole ground temperature profile data as a reference, the estimation of the permafrost thickness of a large number of shallow boreholes in a region is realized, and the thickness of the permafrost layer at the point to be predicted is obtained quickly and accurately.

[0138] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and changes can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0139] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A method for obtaining the thickness of permafrost layer, characterized in that: The method comprises: According to the environmental feature vector, the environmental similarity corresponding to the point to be predicted and each reference hole is obtained, wherein the environmental feature vector includes multiple key environmental factors, and the point to be predicted and each reference hole are both in the permafrost area; Determine the fitting temperature function of the point to be predicted according to the fitting temperature function of the target reference hole and the target offset, wherein the target reference hole is a reference hole with the highest environmental similarity to the point to be predicted, and the target offset is the temperature difference between the point to be predicted and the target reference hole at a first preset depth; The thickness of the permafrost layer at the point to be predicted is determined according to the fitted temperature function of the point to be predicted.

2. The method for obtaining the thickness of permafrost layer according to claim 1, characterized in that: Determining the permafrost thickness of the point to be predicted according to the fitted temperature function of the point to be predicted includes: Substituting 0°C into the fitting temperature function of the point to be predicted to determine the lower limit of the permafrost layer; The thickness of the permafrost layer is determined according to the lower limit of the permafrost layer and the upper limit of the permafrost layer.

3. The method for obtaining the thickness of permafrost layer according to claim 1, characterized in that: The step of obtaining the environmental similarity between the point to be predicted and each reference hole according to the environmental feature vector includes: Determining the environmental distance between the point to be predicted and the reference hole according to the environmental feature vector of the point to be predicted and the environmental feature vector of the reference hole; The environmental distance is converted into the environmental similarity between the point to be predicted and the reference hole using an exponential function.

4. The method for obtaining the thickness of permafrost layer according to claim 1, characterized in that: The method further comprises: Determine the nth geothermal gradient function corresponding to the reference hole according to the nth group of stable geothermal parameter combinations and the instantaneous geothermal gradient set corresponding to the reference hole, wherein the stable geothermal parameter combination includes a stable geothermal gradient depth and a stable geothermal gradient, and the instantaneous geothermal gradient set includes the instantaneous geothermal gradients of the reference hole at each monitoring depth after a first preset depth, 1≤n≤N, and N represents the total number of stable geothermal parameter combinations; Determining an nth primary-order fitting temperature function corresponding to the reference hole according to an nth geothermal gradient function corresponding to the reference hole; Obtaining an evaluation index between the nth primary-order fitting temperature function corresponding to the reference hole and the measured temperature function of the reference hole, wherein the evaluation index includes a determination coefficient and / or a root mean square error; The fitting temperature function corresponding to the reference hole is determined from N primary-order fitting temperature functions according to the evaluation index.

5. The method for obtaining the thickness of permafrost layer according to claim 4, characterized in that: Where GOT(Z)n represents the nth geothermal gradient function, an represents the first fitting parameter in the nth geothermal gradient function, Z represents the depth, and b n represents the second fitting parameter in the nth geothermal gradient function, H n represents the stable geothermal gradient depth in the nth stable geothermal parameter combination, C n represents the stable geothermal gradient in the nth stable geothermal parameter combination, T(Z) n represents the nth primary fitting temperature function, where C1 and C2 are constants.

6. The method for obtaining the thickness of permafrost layer according to claim 4, characterized in that: Before determining the nth geothermal gradient function corresponding to the reference hole according to the nth group of stable geothermal parameter combinations and the instantaneous geothermal gradient set corresponding to the reference hole, the method further includes: Interpolation is performed based on the ground temperature measurement values ​​of the borehole at different measurement depths to obtain the ground temperature estimation values ​​corresponding to each target depth between any two adjacent measurement depths; Determine the instantaneous geothermal gradient of the first type of borehole at each monitoring depth after a first preset depth according to the geothermal measurement values ​​of the first type of borehole at different measurement depths and the geothermal estimation values ​​corresponding to each target depth, wherein the monitoring depth is the measurement depth or the target depth, and the first type of borehole is a borehole having a depth greater than a second preset depth; The first type of boreholes whose instantaneous geothermal gradients after the first preset depth are all positive gradients are determined as reference holes.

7. The method for obtaining the thickness of permafrost layer according to claim 6, characterized in that: The method of determining the instantaneous geothermal gradient of the first type of borehole at each monitoring depth after the first preset depth according to the geothermal measurement values ​​of the first type of borehole at different measurement depths and the geothermal estimation values ​​corresponding to each target depth includes: Obtain ground temperature values ​​at each monitoring depth within the target window; Wherein, the target window is a window centered at the target monitoring depth and having a preset length; According to the ground temperature values ​​at each monitoring depth in the target window, the ground temperature change rate in the target window is determined as the instantaneous ground temperature gradient corresponding to the target monitoring depth.

8. A device for obtaining the thickness of permafrost layer, characterized in that: The device comprises: A first processing unit is used to obtain the environmental similarity corresponding to the point to be predicted and each reference hole according to the environmental feature vector, wherein the environmental feature vector includes multiple key environmental factors, and the point to be predicted and each reference hole are both in a permafrost area; The first processing unit is further used to determine the fitting temperature function of the point to be predicted according to the fitting temperature function of the target reference hole and the target offset, wherein the target reference hole is a reference hole with the highest environmental similarity to the point to be predicted, and the target offset is a temperature difference between the point to be predicted and the target reference hole at a first preset depth; The second processing unit is used to determine the permafrost thickness of the point to be predicted according to the fitting temperature function of the point to be predicted.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that: include: A processor and a memory, the memory being used to store one or more programs; When the one or more programs are executed by the processor, the method according to any one of claims 1 to 7 is implemented.

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