Methods and related devices for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks

Abstract

This invention provides a method and related apparatus for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes. The method includes: selecting a target bank section and obtaining soil layer distribution data and soil physical and mechanical parameters of the target bank section; based on the soil layer distribution data, performing linear fitting on the scattered sequence of natural bank slope morphology to simplify the bank slope morphology; then, according to the soil layer interface elevation and river water level elevation, vertically dividing the simplified bank slope into blocks; based on the divided soil blocks and the soil physical and mechanical parameters, calculating the sliding force and anti-sliding force of each soil block, thereby obtaining the total sliding force and total anti-sliding force; based on the total sliding force and total anti-sliding force, adjusting the slope toe θ value through trial calculations until the total sliding force equals the total anti-sliding force, and outputting the corresponding critical stability slope ratio as 1:1 / tanθ. This invention can solve the problem of the lack of theoretical support in existing empirical methods, and can be used to assess bank slope stability and bank collapse risk, ensuring flood control safety and river stability.

Description

Technical Field

[0001] This invention relates to the field of water conservancy engineering, specifically to a method and related apparatus for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks. Background Technology

[0002] Riverbank collapses are classified into several types, including sinkhole collapses, strip collapses, and wash slope collapses. Sinkhole collapses are sudden, Ω-shaped collapses with an arc-shaped slip surface, involving hundreds of thousands to millions of cubic meters of soil in a single collapse, resulting in significant destructive force. Strip collapses are gradual collapses, forming strips along the bank in plan view, with a nearly straight slip surface. Wash slope collapses are mostly caused by waves, exhibiting a stepped appearance, and are relatively less hazardous. Riverbank collapses possess unique characteristics and complexity. Their uniqueness lies in the fact that riverbanks are constantly changing under the influence of water flow and sediment movement, unlike typical slopes. Their complexity stems from the numerous factors that contribute to riverbank instability. Broadly speaking, these influencing factors include river morphology, water flow patterns, bank shape, geological conditions, protection measures, historical collapse history, and the impact of human activities. These major categories of influencing factors can be further subdivided into the distance between the thalweg and the bank, the near-bank comprehensive slope ratio, the near-bank shoal-channel elevation difference, the flow velocity, and the soil layer distribution. Among these, the near-bank comprehensive slope ratio is an important indicator for measuring bank slope stability and assessing the risk of bank collapse. It is generally believed that riverbank slopes will gradually become steeper and the slope ratio will decrease under the scouring action of water flow. When the slope ratio approaches or reaches the critical stable slope ratio, the bank slope may collapse. Therefore, studying the critical stable slope ratio of riverbank slopes is of great significance for measuring bank slope stability and assessing the risk of bank collapse.

[0003] Currently, the critical stability slope ratio is mostly obtained through statistical analysis of actual observation data, which is an empirical result and lacks theoretical support. It is necessary to study a method for determining the critical stability slope ratio based on the analysis of mechanical equilibrium mechanism. Summary of the Invention

[0004] This invention provides a method and related apparatus for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks, which can solve the problem of the lack of theoretical support in existing empirical methods. Based on the mechanical equilibrium mechanism, the results are reliable and can be used to assess the stability of riverbanks and the risk of bank collapse, thereby ensuring flood control safety and river stability.

[0005] A method for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes includes the following steps:

[0006] Step 1) Determine the research section and soil parameters: Select the target section and obtain the soil layer distribution data and soil physical and mechanical parameters of the target section;

[0007] Step 2) Slope morphology simplification and block division: Based on the soil layer distribution data obtained in Step 1), the scatter sequence of natural slope morphology is fitted with a straight line to simplify the slope morphology; then, according to the soil layer interface elevation and the river water level elevation, the simplified slope is vertically divided into blocks.

[0008] Step 3) Soil stress state analysis: Based on the soil blocks divided in Step 2) and the physical and mechanical parameters of the soil, calculate the sliding force and anti-sliding force of each soil block, and then obtain the total sliding force and total anti-sliding force.

[0009] Step 4) Calculation of critical stability slope ratio: Based on the total sliding force and total anti-sliding force obtained in Step 3), the slope toe θ value is adjusted by trial calculation until the total sliding force equals the total anti-sliding force, and the corresponding critical stability slope ratio is output as 1:1 / tanθ.

[0010] Furthermore, the soil layer distribution data includes soil layer type and thickness, and the soil physical and mechanical parameters include unit weight, friction coefficient, cohesion coefficient, slope angle and internal friction angle.

[0011] Furthermore, in step 2), a linear fit is performed on the scatter plot sequence of natural bank slope morphology to simplify the bank slope morphology, specifically including:

[0012] The top of the slope is simplified to a horizontal line with a fixed elevation, the slope itself is simplified to a straight line with gradually decreasing elevation, and the toe of the slope is simplified to a horizontal line with a fixed elevation; the scatter sequence of the slope segment is (x i , z i ), where i=1…n is the number of scatter points, x i The distance from the starting point is in meters (m); z i The elevation is in meters; the scatter plot sequence is fitted using the linear formula z = ax + b, and the coefficients a and b are calculated using the following formulas:

[0013] ;

[0014] ;

[0015] ;

[0016] ;

[0017] In the formula and These are the average values ​​of the starting point distance and elevation of the scattered points, respectively. The fitted straight line, together with the top and bottom sections of the slope, forms the simplified riverbank slope.

[0018] Furthermore, the formula for calculating the sliding force of each soil block in step 3) is:

[0019] ;

[0020] Frictional force is the component of gravity perpendicular to the sliding surface multiplied by the coefficient of friction.

[0021] ;

[0022] Cohesion is the length of the slip surface multiplied by the cohesion coefficient. ;

[0023] Anti-slip force equals the sum of frictional force and cohesive force: ;

[0024] The formulas for calculating the total sliding force and the total anti-slip force are as follows:

[0025] ;

[0026] ;

[0027] in, The unit weight is the density of the soil block; above the groundwater level, the natural unit weight is used, and below the groundwater level, the buoyant unit weight is used. The unit is N / m³. 3 ; The coefficient of friction of the soil. , θ is the internal friction angle of the soil, in °; c is the cohesion coefficient of the soil, in kPa. θ is the length of the soil block along the slope, in meters; θ is the slope angle, in degrees; n is the total number of soil blocks.

[0028] A device for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes, comprising:

[0029] The geological exploration module is used to select the target shoreline and obtain soil layer distribution data and soil physical and mechanical parameters of the target shoreline.

[0030] The slope morphology simplification and block division module is used to perform linear fitting on the scatter sequence of natural slope morphology based on the acquired soil layer distribution data to simplify the slope morphology; then, based on the soil layer interface elevation and river water level elevation, the simplified slope is vertically divided into blocks.

[0031] The force calculation module is used to calculate the sliding force and anti-sliding force of each soil block based on the divided soil blocks and the physical and mechanical parameters of the soil, and then obtain the total sliding force and total anti-sliding force.

[0032] The critical slope ratio solution module is used to adjust the slope toe θ value based on the obtained total sliding force and total anti-sliding force through trial calculations until the total sliding force equals the total anti-sliding force, and outputs the corresponding critical stable slope ratio as 1:1 / tanθ.

[0033] Furthermore, the soil layer distribution data includes soil layer type and thickness, and the soil physical and mechanical parameters include unit weight, friction coefficient, cohesion coefficient, slope angle and internal friction angle.

[0034] Furthermore, the step of performing linear fitting on the scatter plot sequence of natural bank slope morphology to simplify the bank slope morphology specifically includes:

[0035] The top of the slope is simplified to a horizontal line with a fixed elevation, the slope itself is simplified to a straight line with gradually decreasing elevation, and the toe of the slope is simplified to a horizontal line with a fixed elevation; the scatter sequence of the slope segment is (x i , z i ), where i=1…n is the number of scatter points, x i The distance from the starting point is in meters (m); z i The elevation is in meters; the scatter plot sequence is fitted using the linear formula z = ax + b, and the coefficients a and b are calculated using the following formulas:

[0036] ;

[0037] ;

[0038] ;

[0039] ;

[0040] In the formula and These are the average values ​​of the starting point distance and elevation of the scattered points, respectively. The fitted straight line, together with the top and bottom sections of the slope, forms the simplified riverbank slope.

[0041] Furthermore, the formula for calculating the sliding force of each soil block by the force calculation module is as follows:

[0042] ;

[0043] Frictional force is the component of gravity perpendicular to the sliding surface multiplied by the coefficient of friction.

[0044] ;

[0045] Cohesion is the length of the slip surface multiplied by the cohesion coefficient. ;

[0046] Anti-slip force equals the sum of frictional force and cohesive force: ;

[0047] The formulas for calculating the total sliding force and the total anti-slip force are as follows:

[0048] ;

[0049] ;

[0050] in, The unit weight is the density of the soil block; above the groundwater level, the natural unit weight is used, and below the groundwater level, the buoyant unit weight is used. The unit is N / m³. 3 ; The coefficient of friction of the soil. , θ is the internal friction angle of the soil, in °; c is the cohesion coefficient of the soil, in kPa. θ is the length of the soil block along the slope, in meters; θ is the slope angle, in degrees; n is the total number of soil blocks.

[0051] A comprehensive critical stability slope ratio calculation system for multi-soil riverbank slopes includes: a computer-readable storage medium and a processor;

[0052] The computer-readable storage medium is used to store executable instructions;

[0053] The processor is used to read executable instructions stored in the computer-readable storage medium and execute the method for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes.

[0054] A non-transitory computer-readable storage medium storing a computer program that, when executed by a processor, implements the method for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes.

[0055] The present invention has the following beneficial effects:

[0056] 1. Enhanced Calculation Accuracy through Collaboration: By connecting geological survey, slope morphology simplification, block division, stress calculation, and critical slope ratio solution units in an orderly manner, the accurate transfer of data from survey to result output is achieved. Each unit has a clear and complementary function, ensuring the systematic nature and accuracy of the calculation process.

[0057] 2. Enhanced Methodological Logic and Theoretical Support: A closed-loop logic is formed between steps (parameter determination → morphological simplification → block division → stress analysis → trial calculation and solution). The result of the previous step is directly used as the input of the next step. Based on the mechanical equilibrium mechanism, it breaks through the limitations of empirical statistics and provides a scientific theoretical basis for the critical slope ratio of multi-soil slopes.

[0058] 3. Wide range of applications and strong practicality: It can handle single-layer, double-layer and multi-layer slope structures. Considering the differences in soil layers and the influence of water level, the calculation results are consistent with the measured critical slope ratio range (1:3.15~1:4.16), with high reliability, which helps in the assessment of slope stability and the prevention and control of bank collapse risks.

[0059] 4. Ensure project safety and river stability: Provide key technical support for river management, dike protection and other projects, effectively respond to the situation of bank collapse caused by increased river scouring after a certain project, and maintain flood control safety and river stability. Attached Figure Description

[0060] Figure 1 This is a geological distribution map of a bank slope according to an embodiment of the present invention;

[0061] Figure 2 This is a stratum distribution map of the bank slope according to an embodiment of the present invention;

[0062] Figure 3 This is a simplified diagram of the bank slope according to an embodiment of the present invention;

[0063] Figure 4 This is a schematic diagram of the bank slope segmentation according to an embodiment of the present invention;

[0064] Figure 5 This is a simplified diagram of the force calculation for the strip block according to an embodiment of the present invention;

[0065] Figure 6 This is a flowchart illustrating the method for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes according to an embodiment of the present invention. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0067] Riverbank composition can be categorized into single-layer, double-layer, or multi-layer structures. A single-layer structure refers to a bank slope composed of a single type of sandy soil, clayey soil, or rock. A double-layer structure involves an upper layer of highly erosion-resistant clayey soil and a lower layer of less erosion-resistant sandy soil. A multi-layer structure consists of a mixture of clayey and sandy soils distributed alternately along the depth direction. Statistics show that the vast majority of the banks in the middle and lower reaches of the Yangtze River are double-layered, but a small number also exhibit single-layered and multi-layered structures. Different soil layers exhibit significant differences in their physical and mechanical properties and are also influenced by river levels and groundwater levels.

[0068] The morphology of a natural riverbank slope, from the toe towards the river center, is divided into three sections: the top, the sloping section, and the toe. The top section is located on the existing riverbank surface, with a relatively high and stable elevation. The sloping section gradually decreases in elevation and forms the main body of the slope. The toe section is located in the existing riverbed area, with a lower elevation and a gentler change in elevation. The prerequisite for the stability of the gradually decreasing sloping section is that the sliding force acting on the soil must be less than or equal to the resisting force; otherwise, the slope will collapse, leading to riverbank erosion and affecting flood control safety and river stability. Therefore, based on the ultimate stress equilibrium condition of the sloping section, the critical stable slope ratio of the riverbank can be analyzed. The implementation steps of this invention are explained in detail below with examples.

[0069] Please see Figure 6 The first aspect of this invention provides a method for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes, comprising the following steps:

[0070] 1) Determine the soil parameters of the study section and slope.

[0071] The study focuses on the north bank of a certain river section. Under certain natural conditions, the evolution of the bend on the north bank of this river section is characterized by concave scouring and convex silting. However, after the impoundment of water by a certain project, due to the regulation of the water flow process by the project, the river section has experienced concave silting and convex scouring. Therefore, the scouring of the north bank of this river section has been relatively severe recently.

[0072] Geological surveys of the research section revealed that it possesses a typical two-layered structure. The upper layer consists of silty loam and silty clay with good erosion resistance, while the lower layer is fine silty sand with poor erosion resistance. Detailed stratigraphic distribution can be found in [reference needed]. Figure 1 As shown. The upper layer is approximately 10m thick, and the lower layer is over 20m thick. The elevation of the top of the slope is approximately 37m, the elevation of the riverbed is approximately 7m, and the difference in elevation between the banks is approximately 30.0m.

[0073] (2) Simplification of bank slope morphology and segmentation

[0074] Due to various reasons, the elevation of natural riverbeds always fluctuates. While the elevation change at the top of the slope is not significant, there are minor fluctuations. The elevation of the sloping section generally decreases gradually, but this cannot be quantitatively expressed by a fixed function formula; it can only be represented by connecting a series of scattered points into multiple line segments. The elevation change at the toe of the slope is also not significant, but there are still minor fluctuations. For ease of analysis, the riverbanks are simplified: the top of the slope is simplified to a horizontal line with a fixed elevation, the sloping section is simplified to a straight line with a gradually decreasing elevation, and the toe of the slope is simplified to a horizontal line with a fixed elevation. See [link to relevant documentation]. Figure 3 As shown. The scatter sequence of the slope segment is (x i , z i (i=1…n, the number of scatter points), x i The distance from the starting point is in meters (m); z iHere is the elevation, in meters (m). The scatter plot sequence is fitted using the linear formula z = ax + b, with the coefficients a and b calculated using the following formulas:

[0075]

[0076]

[0077]

[0078]

[0079] In the formula and These represent the average distance between the starting points and the average elevation, respectively. The fitted straight line, together with the top and bottom sections of the slope, forms the simplified riverbank slope.

[0080] Laterally, a unit width is taken at the top of the slope, and a straight line parallel to the slope is drawn as the initial assumed sliding surface. The top, slope, toe, and sliding surface form a large block. Based on this large block, further vertical subdivisions are made. The subdivision principles include two aspects: 1) Due to the heterogeneous nature of the slope soil, different soil layers have significant differences in physical and mechanical properties, and their stress states also differ considerably. Vertical subdivisions are based on the elevation of the soil layer interfaces; 2) The river channel contains water for a long time, resulting in the long-term presence of groundwater within the slope. Since the width of the slope blocks is very small, the groundwater level inside the soil can be considered to be level with the river water level. The physical and mechanical properties of the soil in water-containing and waterless states also differ significantly. Vertical subdivisions are based on the river water level elevation. The subdivision results are shown in […]. Figure 4 As shown, the bank slope is divided into four sections from top to bottom: S1 silty loam block, S2 silty clay block, S3 natural fine sand block, and S4 underwater fine sand block.

[0081] (3) Analysis of soil stress state

[0082] The forces acting on the sliding surface of a soil block include the block's own weight, friction caused by gravity, cohesion between soil particles, and buoyancy in the underwater portion. For soil strip slippage and collapse, the forces acting on the sliding surface are the sliding force and the resisting force. The sliding force mainly originates from the tangential component of gravity on the sliding surface, while the resisting force originates from friction and cohesion. For any soil block Si, its force characteristics are shown in [the diagram]. Figure 5 As shown.

[0083] The magnitudes of each force are calculated using the following formula:

[0084] Strip area:

[0085] Bar gravity:

[0086] The sliding force is the component of gravity along the sliding surface:

[0087] Frictional force is the component of gravity perpendicular to the sliding surface multiplied by the coefficient of friction.

[0088]

[0089] Cohesion is the length of the slip surface multiplied by the cohesion coefficient.

[0090] Anti-slip force equals the sum of frictional force and cohesive force:

[0091] The total sliding force is

[0092] The total anti-skid force is

[0093] In the above formula The unit weight is the density of the soil block; above the groundwater level, the natural unit weight is used, and below the groundwater level, the buoyant unit weight is used. The unit is N / m³. 3 ; The coefficient of friction of the soil. , θ is the internal friction angle of the soil, in °; c is the cohesion coefficient of the soil, in kPa. θ represents the length of the soil block along the slope, in meters; θ is the slope angle, in degrees; and n is the total number of soil blocks. The condition for a bank slope to reach the critical stability slope ratio is the total sliding force. With total anti-skid force equal.

[0094] (4) Calculation of critical stability slope ratio

[0095] An equation can be established based on the equilibrium condition η=τ, with l as the variable. i and θ, where l i Since it is also related to θ, the equation cannot obtain the theoretical value of θ, which must be determined through assumptions and trial calculations. First, a small slope toe value is set as θ1. The total sliding force is calculated as η1 and the anti-sliding force as τ1. The residual Δ is defined as Δ = η1 - τ1. If Δ ≈ 0, θ1 is the angle value corresponding to the critical stable slope ratio; if Δ ≠ 0, θ1 is increased by 2° to become θ2. The above calculation process is repeated until Δ approaches 0. The calculation process is shown in [link to calculation process]. Figure 6 As shown. The final critical stability slope ratio is 1:1 / tanθ.

[0096] Figure 1 The physical and mechanical parameters of each soil layer on the bank slope shown are as follows: the natural bulk density of the silty loam is 1900 N / m³. 3The cohesion is 12.89 kPa, and the internal friction angle is 14.7°; the natural bulk density of the silty clay is 1870 N / m³. 3 The cohesion is 14.83 kPa, and the internal friction angle is 12.01°; the natural bulk density of the fine sand is 1930 N / m³. 3 The cohesion is 0 kPa and the internal friction angle is 28°. The river level is 25.65 m. Based on the above parameters, the initial slope toe θ is set to 10°. After multiple trials, it was found that when the slope toe is 16.1°, the slope is in a critical stable state, and the corresponding critical stable slope ratio is 1:3.46. Assuming that the water level rises further to be level with the top of the beach (36.50 m), the critical stable slope ratio calculated according to this method is 1:3.49. Figure 2 The critical stability slope ratio shown is 1:2.99 when the river level is 25.65m and 1:3.61 when the river level rises to 36.65m, which is level with the top of the shoal.

[0097] Based on the actual bank slope observations in recent years, the bank slope has been retreating year by year due to continuous erosion. Currently, the bank slope is basically retreating in parallel at a certain fixed slope ratio, which means that the slope ratio is close to the critical value. The measured bank slope cross-section results show that the critical slope ratio ranges from about 1:3.15 to 1:4.16, which is basically the same as the critical slope ratio value calculated by this method, indicating that this method is basically reliable.

[0098] A second aspect of the present invention provides a device for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes, comprising:

[0099] The geological exploration module is used to select the target shoreline and obtain soil layer distribution data and soil physical and mechanical parameters of the target shoreline.

[0100] The slope morphology simplification and block division module is used to perform linear fitting on the scatter sequence of natural slope morphology based on the acquired soil layer distribution data to simplify the slope morphology; then, based on the soil layer interface elevation and river water level elevation, the simplified slope is vertically divided into blocks.

[0101] The force calculation module is used to calculate the sliding force and anti-sliding force of each soil block based on the divided soil blocks and the physical and mechanical parameters of the soil, and then obtain the total sliding force and total anti-sliding force.

[0102] The critical slope ratio solution module is used to adjust the slope toe θ value based on the obtained total sliding force and total anti-sliding force through trial calculations until the total sliding force equals the total anti-sliding force, and outputs the corresponding critical stable slope ratio as 1:1 / tanθ.

[0103] Another aspect of the present invention provides a comprehensive critical stability slope ratio calculation system for multi-soil riverbank slopes, comprising: a computer-readable storage medium and a processor;

[0104] The computer-readable storage medium is used to store executable instructions;

[0105] The processor is used to read executable instructions stored in the computer-readable storage medium and execute the comprehensive critical stability slope ratio calculation method for multi-soil riverbanks described in the first aspect.

[0106] In another aspect, the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks as described in the first aspect.

[0107] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0108] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0109] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0110] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for calculating the comprehensive critical stability slope ratio of multi-soil riverbank slopes, characterized in that: Includes the following steps: Step 1) Determine the research section and soil parameters: Select the target section and obtain the soil layer distribution data and soil physical and mechanical parameters of the target section; Step 2) Slope morphology simplification and block division: Based on the soil layer distribution data obtained in Step 1), the scatter sequence of natural slope morphology is fitted with a straight line to simplify the slope morphology; then, according to the soil layer interface elevation and the river water level elevation, the simplified slope is vertically divided into blocks. Step 3) Soil stress state analysis: Based on the soil blocks divided in Step 2) and the physical and mechanical parameters of the soil, calculate the sliding force and anti-sliding force of each soil block, and then obtain the total sliding force and total anti-sliding force. Step 4) Calculation of critical stability slope ratio: Based on the total sliding force and total anti-sliding force obtained in Step 3), the slope toe θ value is adjusted by trial calculation until the total sliding force equals the total anti-sliding force, and the corresponding critical stability slope ratio is output as 1:1 / tanθ.

2. The method for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks as described in claim 1, characterized in that: The soil layer distribution data includes soil layer type and thickness, and the soil physical and mechanical parameters include unit weight, friction coefficient, cohesion coefficient, slope angle and internal friction angle.

3. The method for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks as described in claim 1, characterized in that: Step 2) involves performing linear fitting on the scatter plot sequence of natural bank slope morphology to simplify the bank slope morphology, specifically including: The top of the slope is simplified to a horizontal line with a fixed elevation, the slope itself is simplified to a straight line with gradually decreasing elevation, and the toe of the slope is simplified to a horizontal line with a fixed elevation; the scatter sequence of the slope segment is (x i , z i ), where i=1…n is the number of scatter points, x i The distance from the starting point is in meters (m); z i The elevation is in meters; the scatter plot sequence is fitted using the linear formula z = ax + b, and the coefficients a and b are calculated using the following formulas: ； ； ； ； In the formula and These are the average values ​​of the starting point distance and elevation of the scattered points, respectively. The fitted straight line, together with the top and bottom sections of the slope, forms the simplified riverbank slope.

4. The method for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks as described in claim 2, characterized in that: The formula for calculating the sliding force of each soil block in step 3) is: ； Frictional force is the component of gravity perpendicular to the sliding surface multiplied by the coefficient of friction. ； Cohesion is the length of the slip surface multiplied by the cohesion coefficient. ; Anti-slip force equals the sum of frictional force and cohesive force: ; The formulas for calculating the total sliding force and the total anti-slip force are as follows: ； ； in, The unit weight is the density of the soil block; above the groundwater level, the natural unit weight is used, and below the groundwater level, the buoyant unit weight is used. The unit is N / m³. 3 ; Let be the friction coefficient of the i-th soil layer. , Let be the internal friction angle of the i-th soil layer. c i The cohesion coefficient of the i-th soil layer, in kPa; θ is the length of the soil block along the slope, in meters; θ is the slope angle, in degrees; n is the total number of soil blocks.

5. A device for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks, characterized in that: include: The geological exploration module is used to select the target shoreline and obtain soil layer distribution data and soil physical and mechanical parameters of the target shoreline. The slope morphology simplification and block division module is used to perform linear fitting on the scatter sequence of natural slope morphology based on the acquired soil layer distribution data to simplify the slope morphology. Then, based on the elevation of the soil layer interface and the river water level, the simplified bank slope is vertically divided into blocks. The force calculation module is used to calculate the sliding force and anti-sliding force of each soil block based on the divided soil blocks and the physical and mechanical parameters of the soil, and then obtain the total sliding force and total anti-sliding force. The critical slope ratio solution module is used to adjust the slope toe θ value based on the obtained total sliding force and total anti-sliding force through trial calculations until the total sliding force equals the total anti-sliding force, and outputs the corresponding critical stable slope ratio as 1:1 / tanθ.

6. The multi-soil-layer riverbank slope comprehensive critical stability slope ratio calculation device as described in claim 5, characterized in that: The soil layer distribution data includes soil layer type and thickness, and the soil physical and mechanical parameters include unit weight, friction coefficient, cohesion coefficient, slope angle and internal friction angle.

7. The multi-soil-layer riverbank slope comprehensive critical stability slope ratio calculation device as described in claim 5, characterized in that: The method of performing linear fitting on the scatter plot sequence of natural bank slope morphology to simplify the bank slope morphology specifically includes: The top of the slope is simplified to a horizontal line with a fixed elevation, the slope itself is simplified to a straight line with gradually decreasing elevation, and the toe of the slope is simplified to a horizontal line with a fixed elevation; the scatter sequence of the slope segment is (x i , z i ), where i=1…n is the number of scatter points, x i The distance from the starting point is in meters (m); z i The elevation is in meters; the scatter plot sequence is fitted using the linear formula z = ax + b, and the coefficients a and b are calculated using the following formulas: ； ； ； ； In the formula and These are the average values ​​of the starting point distance and elevation of the scattered points, respectively. The fitted straight line, together with the top and bottom sections of the slope, forms the simplified riverbank slope.

8. The multi-soil-layer riverbank slope comprehensive critical stability slope ratio calculation device as described in claim 6, characterized in that: The formula used by the force calculation module to calculate the sliding force of each soil block is as follows: ； Frictional force is the component of gravity perpendicular to the sliding surface multiplied by the coefficient of friction. ； Cohesion is the length of the slip surface multiplied by the cohesion coefficient. ; Anti-slip force equals the sum of frictional force and cohesive force: ; The formulas for calculating the total sliding force and the total anti-slip force are as follows: ； ； in, The unit weight is the density of the soil block; above the groundwater level, the natural unit weight is used, and below the groundwater level, the buoyant unit weight is used. The unit is N / m³. 3 ; Let be the friction coefficient of the i-th soil layer. , c is the internal friction angle of the i-th soil layer, in degrees. i The cohesion coefficient of the i-th soil layer, in kPa; θ is the length of the soil block along the slope, in meters; θ is the slope angle, in degrees; n is the total number of soil blocks.

9. A comprehensive critical stability slope ratio calculation system for multi-soil riverbank slopes, comprising: Computer-readable storage media and processors; The computer-readable storage medium is used to store executable instructions; The processor is used to read executable instructions stored in the computer-readable storage medium and execute the method for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks as described in any one of claims 1-4.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for calculating the comprehensive critical stability slope ratio of multi-soil riverbanks according to any one of claims 1-4.

Images