Combined monitoring and prevention method suitable for bank slope instability failure under erosion condition

Abstract

A combined monitoring method suitable for bank slope instability failure under an erosion condition is characterized in that the combined monitoring method comprises hydraulic gradient monitoring, soil shear strength monitoring and soil surface displacement field monitoring; the hydraulic gradient monitoring result is used for obtaining hydraulic gradient safety coefficients at different area positions of the bank slope, the soil body shear strength monitoring result is used for obtaining the overall anti-slip safety coefficient of the bank slope soil body, and the soil body surface displacement field monitoring result is used for drawing a soil body surface shear strain cloud chart. The combined monitoring method is suitable for various types of bank slope stratums. According to the method, the influence of the erosion action on the stability of the bank slope soil body structure is accurately detected from three angles of hydraulic gradient, soil body shear strength and soil body surface displacement, and early-stage accurate prevention and control of channel bank slope instability failure are achieved. Meanwhile, the invention further provides a bank slope instability damage grading prevention and control method based on the combined monitoring result, and economic, efficient, safe and reliable anti-sliding reinforcement treatment of the channel bank slope is achieved.

Description

Technical Field

[0001] The invention relates to a combined monitoring and prevention method for bank slope instability and damage under erosion conditions, and belongs to the field of geotechnical engineering. Background Art

[0002] The bank slopes of waterways have long been subjected to erosion caused by ship surge loads. Erosion can cause the loss of bank slope soil components, increase the porosity, and reduce strength, making it prone to instability and landslide damage. On the one hand, the instability and damage of the waterway bank slopes can cause siltation of the waterway, and on the other hand, it can cause damage to the bank slope lanes and even induce water from the waterway to flow back into villages and towns, causing great economic and property losses. Therefore, preventing the erosion and instability of the waterway bank slopes plays an important role in protecting the ecological environment of the waterway and maintaining the high-quality development of the local economy.

[0003] At present, the monitoring of bank slopes is mostly carried out by using Beidou positioning, radar measurement and control, drone mapping, etc. (such as CN118393526A, CN202110638189.7, CN111854699A), or monitoring methods based on detection data and acoustic influence fusion (such as CN116540238B), or multi-beam mobile monitoring (such as CN109398624A), or microseismic technology (CN110220979A), etc. to monitor the stability of bank slope soil. It should be noted that these existing technical solutions are based on the strain of the soil to determine whether the bank slope has the risk of instability and landslide. However, before the bank slope surface has a large displacement deformation, the internal erosion of the bank slope has already occurred, and when the internal erosion of the bank slope is transmitted to the surface and shows a large deformation, the strength of the bank slope soil has been greatly reduced, which is extremely unfavorable for bank slope rescue and disaster relief, because when the strength of the bank slope soil is greatly lost, the use of heavy-duty machinery to reinforce the bank slope will increase the risk of landslides. Therefore, there is an urgent need for a comprehensive monitoring system that can simultaneously monitor the internal erosion of the bank slope soil and the surface deformation, provide sufficient early warning information before the bank slope surface undergoes a large deformation, provide sufficient time and safety guarantee for bank slope rescue and reinforcement, and ensure the long-term safe and stable operation of the channel bank slope. Summary of the invention

[0004] In order to overcome the risk uncertainty brought about by the current landslide disaster assessment of waterway slopes based on a single indicator of surface displacement and ensure the long-term safe and stable operation of the waterway slopes, the present invention provides a joint monitoring and prevention method for slope instability and destruction under erosion conditions.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] A joint monitoring method for bank slope instability and failure under erosion conditions, characterized in that the joint monitoring method includes hydraulic gradient monitoring, soil shear strength monitoring and soil surface displacement field monitoring;

[0007] The hydraulic gradient monitoring is performed by arranging pore water pressure sensors at different positions and depths of the bank slope to monitor the change of pore water pressure of the bank slope soil, and calculating the hydraulic gradients at different positions and depths according to formula (1);

[0008]

[0009] Where: Δu is the pore water pressure difference measured by two pore water pressure gauges; ρ w is the density of water; g is the acceleration of gravity; L is the distance between the two pore water pressure gauges;

[0010] The soil shear strength monitoring combines indoor test results and slope soil monitoring indicators to evaluate the shear strength of slope soil at different depths, including soil pressure monitoring, shear wave velocity monitoring and indoor unit body testing;

[0011] The soil pressure monitoring is performed by arranging soil pressure sensors at different positions and depths of the slope to monitor the total soil pressure of the slope, and combining the pore water pressure monitoring results at the same position to calculate the effective stress of the soil at different positions and depths according to formula (2);

[0012] σ′ m =σ-u (2) Where: σ' m is the effective stress of soil; σ is the monitoring result of soil pressure; u is the monitoring result of pore water pressure;

[0013] The shear wave velocity monitoring is used to obtain the shear wave velocity of the bank slope soil at different positions and depths, and calculate the porosity ratio of the bank slope soil at different positions and depths according to formula (3);

[0014]

[0015] Where: e is the porosity of the soil; ρ is the density of the soil; V s is the shear wave velocity measurement result; A is the material constant, which is obtained by fitting the indoor unit body test results; n is the constant describing the influence of stress on the shear wave velocity of the soil, which is determined by fitting the indoor unit body test results;

[0016] The indoor unit body test includes a shear test and a consolidation-shear wave velocity measurement test under different porosity ratio conditions, wherein the shear test is used to obtain the quantitative correlation between the soil porosity ratio and the soil internal friction angle, and the consolidation-shear wave velocity measurement test is used to obtain the A value and the n value in formula (3);

[0017] Combining the indoor unit test results and the slope soil measurement indicators, the shear strength of the soil at different positions and depths is calculated according to formula (4);

[0018]

[0019] Where: τ is the shear strength of the soil; is the function of the internal friction angle and porosity ratio of the soil; c' is the cohesion of the soil;

[0020] The soil surface displacement field monitoring is performed by setting a plurality of fixed and non-fixed monitoring points on the surface, then taking photos of the surface, analyzing the surface displacement field of the slope soil by comparing the pixel positions of the non-fixed monitoring points in the images of different time periods, and calculating the surface shear strain distribution of the slope soil according to formula (5); the pixel position change is judged and measured based on the fixed monitoring points;

[0021]

[0022] Where: Δl is the surface deformation of the slope; L0 is the initial distance of the surface measurement point.

[0023] Preferably, the hydraulic gradient monitoring results at different positions and depths can be used to draw a hydraulic gradient cloud map of the slope area according to the linear interpolation method; hydraulic gradient tests under different porosity conditions are carried out to obtain the relationship between the critical hydraulic gradient and the porosity when the soil body is damaged by piping; based on the relationship between the hydraulic gradient cloud map and the critical hydraulic gradient, the hydraulic gradient safety factor at different regional positions is calculated according to formula (6):

[0024]

[0025] Where: F w is the hydraulic gradient safety factor; i cr is the critical hydraulic gradient; i is the hydraulic gradient.

[0026] Preferably, the soil shear strength monitoring results are used to draw soil effective stress distribution cloud diagrams and calculate the overall anti-sliding safety factor of the slope soil, wherein the anti-sliding safety factor calculation method is shown in formula (7):

[0027]

[0028] Where: K is the anti-sliding safety factor; the subscript i indicates that the slope is divided into i strips; l i is the bottom sliding length of the i-th bar.

[0029] Preferably, the monitoring result of the soil surface displacement field is used to draw a soil surface shear strain cloud map; the monitoring of the soil surface displacement field can be implemented by drone aerial photography or obtained by taking pictures with a camera at a fixed height.

[0030] Preferably, the shear wave velocity monitoring can be implemented by surface wave method, down-hole method and cross-hole method; when the down-hole method and cross-hole method are used for measurement, the shear wave detector needs to be placed in the borehole and be consistent with the burial depth of the pore water pressure sensor and the soil pressure sensor.

[0031] Preferably, the pore water pressure sensor and the earth pressure sensor are buried in the soil of the slope through drilling and are located at the same depth; the monitoring density of the pore water pressure sensor and the earth pressure sensor is: the monitoring distance in the depth direction exceeds 5m from the bottom of the slope, and the monitoring interval does not exceed 3m; the monitoring distance in the direction perpendicular to the slope is consistent with that in the depth direction, and the monitoring interval does not exceed 5m; the monitoring distance along the slope is related to the engineering requirements, and the monitoring interval does not exceed 10m; the starting points of the monitoring distances are all the tops of the slope.

[0032] Preferably, the stratum types of the slope soil body include one or more of clay, clay silt, clay sand, silt, silty clay, silty sand, sand, sandy clay, sandy silt, sandy gravel, gravel soil, and gravelly sand.

[0033] A graded prevention and control method for bank instability based on bank joint monitoring results, characterized in that the graded prevention and control method includes the following parts:

[0034] (1) When the hydraulic gradient safety factor is greater than 2, the anti-sliding safety factor is greater than 1.2, and the maximum surface shear strain is less than 0.01%, there is no need to reinforce the slope;

[0035] (2) When the hydraulic gradient safety factor is between 1 and 2, or the anti-sliding safety factor is between 1 and 1.2, or the maximum surface shear strain is less than 0.01%, a single reinforcement measure can be appropriately adopted for the bank slope, including cutting to reduce load, anchor reinforcement, and bank slope surface waterproofing;

[0036] (3) When the hydraulic gradient safety factor is between 0.95 and 1, or the anti-sliding safety factor is between 0.9 and 1, or the maximum surface shear strain is between 0.01% and 0.1%, single or combined reinforcement measures shall be taken for the slope, including cutting and unloading, anchor reinforcement, anti-sliding pile reinforcement, grouting reinforcement of the eroded surface, and slope surface waterproofing;

[0037] (4) When the hydraulic gradient safety factor is less than 0.95, or the anti-sliding safety factor is less than 0.9, or the maximum surface shear strain is greater than 0.1%, a combination of reinforcement measures must be taken immediately for the slope, including cutting to reduce load, anchor reinforcement, anti-sliding pile reinforcement, grouting reinforcement of the erosion surface, slope surface waterproofing, and slope backwatering.

[0038] The present invention has the following beneficial effects:

[0039] 1) The present invention comprehensively evaluates the stability of the channel bank slope under erosion load from three perspectives: hydraulic gradient, soil shear strength and soil surface displacement. The multi-angle evaluation is conducive to accurately detecting the impact of erosion on the stability of the bank slope soil structure, and realizing early and accurate prevention and control of the instability and damage of the channel bank slope;

[0040] 2) The present invention provides a graded prevention and control method for bank slope instability under different conditions based on the range of three types of safety factor values: hydraulic gradient safety factor, anti-sliding safety factor and maximum surface shear strain, combined with the applicability and economy of different bank slope anti-sliding reinforcement treatment methods, to achieve economical, efficient, safe and reliable anti-sliding reinforcement treatment of waterway bank slopes;

[0041] 3) Based on indoor unit body tests and on-site shear wave velocity tests, soil pressure monitoring, and pore water pressure monitoring, the present invention can accurately detect the change in soil porosity caused by slope soil erosion and accurately predict the attenuation of soil shear strength, providing theoretical and data support for the design of slope anti-sliding reinforcement;

[0042] 4) The present invention selects shear wave velocity as the site porosity measurement index and scale. Compared with the traditional penetration test index, it has the advantage of indoor and outdoor combined measurement. It is a high-quality non-destructive testing method, and the test results have high repeatability and low testing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the combined monitoring method for bank slope instability and failure according to the present invention.

[0044] Figure 2 It is a plan view schematic diagram of the sensor arrangement according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit and protection scope of the claims of the present invention shall fall within the protection scope of the present invention.

[0047] The monitoring area of ​​a channel bank slope is 100m, the distance between the bank slope surface and the channel bottom is 8m, and the stratum of the bank slope is homogeneous silty sand. The stability of the channel bank slope under erosion conditions is evaluated:

[0048] First, it is necessary to design the sensor layout for the channel slope, specifically: the monitoring range of the pore water pressure sensor and the soil pressure sensor is 15m in the depth direction, 15m in the direction perpendicular to the slope, and 100m in the direction parallel to the slope; the monitoring density of the pore water pressure sensor and the soil pressure sensor is 3m apart in the depth direction, 5m apart in the direction perpendicular to the slope, and 10m apart in the direction parallel to the slope, requiring a total of 220 pore water pressure sensors and soil pressure sensors. The shear wave velocity test is carried out using the down-hole method. The shear wave excitation source is arranged at the center of the adjacent surface boreholes, and the detector is placed along the borehole at the same depth as the pore water pressure sensor and the soil pressure sensor. Fixed monitoring points and non-fixed monitoring points are set in the middle of adjacent boreholes, and 4 non-fixed monitoring points and 2 fixed monitoring points are set perpendicular to the slope. The corresponding sensor layout is as follows: Figure 2 shown.

[0049] Secondly, the slope soil was sampled and indoor unit tests were carried out, including shear tests under different porosity ratios, consolidation-shear wave velocity measurement tests, and hydraulic gradient tests under different porosity ratios. The shear test was used to obtain the quantitative correlation between the porosity ratio of the soil and the internal friction angle of the soil; the consolidation-shear wave velocity measurement test was used to obtain the A value and n value in formula (3); and the hydraulic gradient test was used to obtain the quantitative correlation between the critical hydraulic gradient and the porosity ratio of the soil.

[0050] Finally, joint monitoring of slope instability and failure under erosion conditions was carried out and the corresponding safety factor was calculated:

[0051] (i) By arranging pore water pressure sensors at different positions and depths of the slope, the pore water pressure changes of the slope soil are monitored, and the hydraulic gradients at different positions and depths are calculated according to formula (1).

[0052]

[0053] Where: Δu is the pore water pressure difference measured by two pore water pressure gauges; ρ w is the density of water; g is the acceleration due to gravity; L is the distance between the two pore water pressure gauges.

[0054] The monitoring results of hydraulic gradients at different positions and depths can be used to draw the hydraulic gradient cloud map of the slope area according to the linear interpolation method; based on the relationship between the hydraulic gradient cloud map and the critical hydraulic gradient, the hydraulic gradient safety factor at different regional positions is calculated according to formula (6):

[0055]

[0056] Where: F w is the hydraulic gradient safety factor; i cr is the critical hydraulic gradient; i is the hydraulic gradient.

[0057] (ii) By arranging soil pressure sensors at different positions and depths on the slope to monitor the total soil pressure on the slope, combined with the pore water pressure monitoring results at the same position, the effective stress of the soil at different positions and depths is calculated according to formula (2).

[0058] σ′ m =σ-u (2) Where: σ' m is the effective stress of soil; σ is the soil pressure monitoring result; u is the pore water pressure monitoring result.

[0059] Shear wave velocity monitoring is carried out to obtain the shear wave velocity of the slope soil at different positions and depths, and the porosity ratio at different positions and depths of the slope soil is calculated according to formula (3).

[0060]

[0061] Where: e is the porosity of the soil; ρ is the density of the soil; V s is the shear wave velocity measurement result; A is the material constant, which is obtained by fitting the indoor unit test results; n is a constant that describes the influence of stress on the shear wave velocity of soil, which is determined by fitting the indoor unit test results.

[0062] Based on the quantitative correlation between the soil porosity and the internal friction angle determined by the indoor unit body test, the shear strength of the soil at different positions and depths is calculated in combination with formula (4).

[0063]

[0064] Where: τ is the shear strength of the soil; is a function of the internal friction angle and porosity of the soil; c' is the cohesion of the soil.

[0065] The monitoring results of soil shear strength are used to draw the soil effective stress distribution cloud map and calculate the overall anti-sliding safety factor of the slope soil. The calculation method of the anti-sliding safety factor is shown in formula (7):

[0066]

[0067] Where: K is the anti-sliding safety factor; the subscript i indicates that the slope is divided into i strips; l i is the bottom sliding length of the i-th bar.

[0068] (iii) The slope surface is photographed by drone, and the surface displacement field of the slope soil is analyzed by comparing the pixel positions of non-fixed monitoring points in the images at different time periods. The surface shear strain distribution of the slope soil is calculated according to formula (5). The pixel position changes are judged and measured based on the fixed monitoring points. The monitoring results of the soil surface displacement field are then used to draw the soil surface shear strain cloud map.

[0069]

[0070] Where: Δl is the surface deformation of the slope; L0 is the initial distance of the surface measurement point.

[0071] Then, according to the monitoring results of (i)-(iii), determine the corresponding graded prevention and control methods:

[0072] (1) When the hydraulic gradient safety factor is greater than 2, the anti-sliding safety factor is greater than 1.2, and the maximum surface shear strain is less than 0.01%, there is no need to reinforce the slope;

[0073] (2) When the hydraulic gradient safety factor is between 1 and 2, or the anti-sliding safety factor is between 1 and 1.2, or the maximum surface shear strain is less than 0.01%, a single reinforcement measure can be appropriately adopted for the bank slope, including cutting to reduce load, anchor reinforcement, and bank slope surface waterproofing;

[0074] (3) When the hydraulic gradient safety factor is between 0.95 and 1, or the anti-sliding safety factor is between 0.9 and 1, or the maximum surface shear strain is between 0.01% and 0.1%, single or combined reinforcement measures shall be taken for the slope, including cutting and unloading, anchor reinforcement, anti-sliding pile reinforcement, grouting reinforcement of the eroded surface, and slope surface waterproofing;

[0075] (4) When the hydraulic gradient safety factor is less than 0.95, or the anti-sliding safety factor is less than 0.9, or the maximum surface shear strain is greater than 0.1%, a combination of reinforcement measures must be taken immediately for the slope, including cutting to reduce load, anchor reinforcement, anti-sliding pile reinforcement, grouting reinforcement of the erosion surface, slope surface waterproofing, and slope backwatering.

[0076] The monitoring results of this waterway are as follows: the hydraulic gradient safety factor of the bank slope at the middle position along the waterway (width 40m) is 0.98, the anti-sliding safety factor is 1.1, and the maximum surface shear strain is 0.01%. The monitoring results show that there is no risk of landslide instability in the bank slope, but there is a certain risk of piping, so the design adopts erosion surface grouting reinforcement; the monitoring results at the end position along the waterway (width 20m) are the hydraulic gradient safety factor of 1.05, the anti-sliding safety factor of 0.95, and the maximum surface shear strain of 0.05%. The monitoring results show that the bank slope at the end of the waterway has a slight risk of instability and landslide, but no risk of piping, so the design adopts anchor reinforcement; the monitoring results at the other end position along the waterway (width 40m) are the hydraulic gradient safety factor of 1.05, the anti-sliding safety factor of 1.15, and the maximum surface shear strain of 0.01%. The monitoring results show that there is no risk of instability and landslide and piping in the bank slope at the other end position of the waterway. In summary, the bank slope of the waterway needs to be reinforced in a refined manner using different regions and technologies to achieve the best economic benefits.

Claims

1. A joint monitoring method for bank slope instability and failure under erosion conditions, characterized in that: The combined monitoring method includes monitoring of hydraulic gradient, monitoring of soil shear strength and monitoring of soil surface displacement field; The hydraulic gradient monitoring is performed by arranging pore water pressure sensors at different positions and depths of the bank slope to monitor the change of pore water pressure of the bank slope soil, and calculating the hydraulic gradients at different positions and depths according to formula (1); Where: Δu is the pore water pressure difference measured by two pore water pressure gauges; ρ w is the density of water; g is the acceleration of gravity; L is the distance between the two pore water pressure gauges; The soil shear strength monitoring combines indoor test results and slope soil monitoring indicators to evaluate the shear strength of slope soil at different depths, including soil pressure monitoring, shear wave velocity monitoring and indoor unit body testing; The soil pressure monitoring is performed by arranging soil pressure sensors at different positions and depths of the slope to monitor the total soil pressure of the slope, and combining the pore water pressure monitoring results at the same position to calculate the effective stress of the soil at different positions and depths according to formula (2); in m =σ-u (2) Where: σ' m is the effective stress of soil; σ is the monitoring result of soil pressure; u is the monitoring result of pore water pressure; The shear wave velocity monitoring is used to obtain the shear wave velocity of the bank slope soil at different positions and depths, and calculate the porosity ratio of the bank slope soil at different positions and depths according to formula (3); Where: e is the porosity of the soil; ρ is the density of the soil; V s is the shear wave velocity measurement result; A is the material constant, which is obtained by fitting the indoor unit body test results; n is the constant describing the influence of stress on the shear wave velocity of the soil, which is determined by fitting the indoor unit body test results; The indoor unit body test includes a shear test and a consolidation-shear wave velocity measurement test under different porosity ratio conditions, wherein the shear test is used to obtain the quantitative correlation between the soil porosity ratio and the soil internal friction angle, and the consolidation-shear wave velocity measurement test is used to obtain the A value and the n value in formula (3); Combining the indoor unit test results and the slope soil measurement indicators, the shear strength of the soil at different positions and depths is calculated according to formula (4); Where: τ is the shear strength of the soil; is the function of the internal friction angle and porosity ratio of the soil; c' is the cohesion of the soil; The soil surface displacement field monitoring is performed by setting a plurality of fixed and non-fixed monitoring points on the surface, then taking photos of the surface, analyzing the surface displacement field of the slope soil by comparing the pixel positions of the non-fixed monitoring points in the images of different time periods, and calculating the surface shear strain distribution of the slope soil according to formula (5); the pixel position change is judged and measured based on the fixed monitoring points; Where: Δl is the surface deformation of the slope; L0 is the initial distance of the surface measurement point.

2. The joint monitoring method according to claim 1, characterized in that: The hydraulic gradient monitoring results at different positions and depths can be used to draw the hydraulic gradient cloud map of the slope area according to the linear interpolation method; hydraulic gradient tests under different porosity conditions are carried out to obtain the relationship between the critical hydraulic gradient and the porosity when the soil body is damaged by piping; based on the relationship between the hydraulic gradient cloud map and the critical hydraulic gradient, the hydraulic gradient safety factor at different regional positions is calculated according to formula (6): Where: F w is the hydraulic gradient safety factor; i cr is the critical hydraulic gradient; i is the hydraulic gradient.

3. The joint monitoring method according to claim 1, characterized in that: The soil shear strength monitoring results are used to draw the soil effective stress distribution cloud map and calculate the overall anti-sliding safety factor of the slope soil. The anti-sliding safety factor calculation method is shown in formula (7): Where: K is the anti-sliding safety factor; the subscript i indicates that the slope is divided into i strips; l i is the bottom sliding length of the i-th bar.

4. The joint monitoring method according to claim 1, characterized in that: The monitoring result of the soil surface displacement field is used to draw a soil surface shear strain cloud map; the soil surface displacement field monitoring can be implemented by drone aerial photography or obtained by taking photos with a camera at a fixed height.

5. The joint monitoring method according to claim 1, characterized in that: The shear wave velocity monitoring can be implemented by the surface wave method, the down-hole method and the cross-hole method; when the down-hole method and the cross-hole method are used for measurement, the shear wave detector needs to be placed in the borehole and be consistent with the burial depth of the pore water pressure sensor and the soil pressure sensor.

6. The joint monitoring method according to claim 1, characterized in that: The pore water pressure sensor and soil pressure sensor are buried in the soil of the slope through drilling and are located at the same depth; the monitoring density of the pore water pressure sensor and the soil pressure sensor is: the monitoring distance in the depth direction exceeds 5m from the bottom of the slope, and the monitoring interval does not exceed 3m; the monitoring distance in the direction perpendicular to the slope is consistent with that in the depth direction, and the monitoring interval does not exceed 5m; the monitoring distance along the slope is related to the engineering requirements, and the monitoring interval does not exceed 10m; the starting points of the monitoring distances are all the tops of the slope.

7. The joint monitoring method according to claim 1, characterized in that: The stratum types of the slope soil body include one or more of clay, clay silt, clay sand, silt, silty clay, silty sand, sand, sandy clay, sandy silt, sandy gravel, gravel soil, and gravelly sand.

8. A method for preventing and controlling bank slope instability based on claim 1, characterized in that: The hierarchical prevention and control method includes the following parts: (1) When the hydraulic gradient safety factor is greater than 2, the anti-sliding safety factor is greater than 1.2, and the maximum surface shear strain is less than 0.01%, there is no need to reinforce the slope; (2) When the hydraulic gradient safety factor is between 1 and 2, or the anti-sliding safety factor is between 1 and 1.2, or the maximum surface shear strain is less than 0.01%, a single reinforcement measure can be appropriately adopted for the bank slope, including cutting to reduce load, anchor reinforcement, and bank slope surface waterproofing; (3) When the hydraulic gradient safety factor is between 0.95 and 1, or the anti-sliding safety factor is between 0.9 and 1, or the maximum surface shear strain is between 0.01% and 0.1%, single or combined reinforcement measures shall be taken for the slope, including cutting and unloading, anchor reinforcement, anti-sliding pile reinforcement, grouting reinforcement of the eroded surface, and slope surface waterproofing; (4) When the hydraulic gradient safety factor is less than 0.95, or the anti-sliding safety factor is less than 0.9, or the maximum surface shear strain is greater than 0.1%, a combination of reinforcement measures must be taken immediately for the slope, including cutting to reduce load, anchor reinforcement, anti-sliding pile reinforcement, grouting reinforcement of the erosion surface, slope surface waterproofing, and slope backwatering.

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