A monitoring and early warning method for geological disasters caused by landslides along oil and gas pipelines.

Abstract

This invention relates to the field of geological disaster early warning technology, and discloses a monitoring and early warning method for landslide geological disasters along oil and gas pipelines. The method includes: Step 1: Modeling and analyzing the landslide slope to determine that the landslide slope includes the rock mass that has collapsed and the slope surface that has not collapsed, wherein the bottom of the collapsed rock mass is a plastic zone; Step 2: Obtaining the self-weight of the rock mass, the anti-sliding force of the rock mass on the slope surface, and the sliding force of the rock mass; analyzing the pressure on the plastic zone from the rock mass during a landslide; and simulating the crack opening degree between the rock mass and the slope surface; Step 3: Based on the crack opening degree, creating an early warning level, and issuing an early warning corresponding to the specific crack opening degree value. This method can predict and issue early warnings for different levels of landslide disasters, and can solve the problem of landslide prevention and mitigation.

Description

Technical Field

[0001] This invention relates to the field of geological disaster early warning technology, and in particular to a monitoring and early warning method for geological disasters caused by landslides along oil and gas pipelines. Background Technology

[0002] Geological hazards affecting oil and gas pipelines include landslides, collapses, and water damage. Among these, collapses primarily cause damage through traction, impact, and burial. Pipelines laid in relatively loose rock and soil, with excavated edges forming steep slopes, are susceptible to collapse due to atmospheric precipitation and weathering. If a slope collapses, the pipeline will be exposed and subjected to impact from debris, leading to rupture. Furthermore, pipelines laid at the foot of steep cliffs below potential collapse zones are also at risk. If a collapse occurs, the falling debris can crush or even deform the pipeline, compromising its safety. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a monitoring and early warning method for geological disasters caused by landslides along oil and gas pipelines, which addresses the above-mentioned problems. This method models the landslide slope and uses stress analysis to calculate the real-time state of the landslide slope, thereby issuing corresponding prediction and early warning signals and providing a scientific basis for the protection against landslide disasters.

[0004] The technical solution adopted in this invention is as follows: A method for monitoring and early warning of geological disasters caused by landslides along oil and gas pipelines, comprising:

[0005] Step 1: Model and analyze the collapsed slope to determine that the collapsed slope includes the rock mass that has collapsed and the slope surface that has not collapsed. The bottom of the collapsed rock mass is a plastic zone.

[0006] Step 2: Obtain the self-weight of the rock mass, the anti-sliding force of the rock mass on the slope, and the sliding force of the rock mass. Analyze the pressure from the rock mass on the plastic zone when a collapse occurs, and simulate the opening and closing degree of cracks between the rock mass and the slope.

[0007] Step 3: Combine the crack opening degree to create an early warning level, and issue an early warning of the corresponding level based on the specific crack opening degree value.

[0008] Furthermore, step 1, specifically the modeling and analysis of the collapsed slope, includes:

[0009] Based on the geological conditions of actual landslides, the landslide slope is simplified into a trapezoid, the landslide rock mass into a parallelogram, and the plastic zone into a triangle, thus constructing a physical force model of the landslide slope.

[0010] Furthermore, step 2 specifically includes:

[0011] Step 21: Obtain the self-weight G of the rock mass, using the following formula:

[0012]

[0013] Where G represents the self-weight of the rock mass (kN), S BCDE This represents the area (m²) of the rock mass after the plastic zone has been removed. 2 ), where γ represents the unit weight of the rock mass (kN / m³). 3 ), where a represents the horizontal width of the rock mass (m), H represents the height of the collapse slope (m), and α represents the slope of the collapse rock mass (°);

[0014] Step 22: Obtain the anti-sliding force R of the rock mass on the slope surface φ The specific formula is as follows:

[0015] R φ =λtanφ·G cosα (2)

[0016] Among them, R φ λ represents the sliding resistance (kN), φ represents the internal friction angle of the rock mass (°), λ represents the contact coefficient (0.75), α represents the slope of the collapsed rock mass (°), and G represents the self-weight of the rock mass (kN).

[0017] The specific formula for obtaining the sliding force T of the rock mass is as follows:

[0018] T = G sinα (3)

[0019] Where T represents the sliding force (kN), G represents the self-weight of the rock mass (kN), and α represents the slope of the collapsed rock mass (°);

[0020] Step 23: Based on the obtained anti-slip force R φ Given the sliding force T, we further analyze the effective pressure on the top surface of the plastic zone, which is expressed as stress σ, as follows:

[0021]

[0022] Among them, S BE σ1 represents the length (m) of the top surface of the plastic zone, σ1 represents the stress (MPa), and T represents the sliding force (kN);

[0023] Step 24: Based on the plasticity condition, determine the critical condition for stress σ1 that must be satisfied when the rock mass collapses. The critical condition is as follows:

[0024]

[0025] Where σ1 represents stress (MPa), denoted by , where is the internal friction angle of the rock mass in the plastic zone (°), and c represents the cohesion of the rock mass in the plastic zone (MPa).

[0026] Step 25: By integrating equations (4) and (5) and substituting them into equation (1), the relationship between the critical inclination angle a0 for maintaining slope stability and the slope height H can be obtained, as follows:

[0027]

[0028] Where H represents the height of the collapsed slope (m), and c represents the cohesion of the rock mass in the plastic zone (MPa). γ represents the internal friction angle (°) of the rock mass in the plastic zone, and γ represents the unit weight of the rock mass (kN / m³). 3 ), φ represents the internal friction angle of the rock mass (°), α0 represents the critical dip angle for the slope to remain stable (°), a represents the horizontal width of the rock mass (m), and λ represents the contact coefficient (0.75);

[0029] Step 26: The crack opening degree L0 between the slope surface and the rock mass is obtained as follows:

[0030]

[0031] Where L0 represents the crack opening degree (m), H represents the slope height (m), β represents the slope of the collapsed rock mass (°), and α0 represents the critical dip angle for the slope to remain stable (°).

[0032] Furthermore, step 3, in conjunction with the crack opening degree, includes the following steps for creating an early warning level:

[0033] Based on the geological disaster meteorological early warning classification formulated by the Ministry of Land and Resources and the China Meteorological Administration, and combined with the numerical range of crack opening degree, the early warning level is formulated.

[0034] Furthermore, the warning levels include four levels: blue warning, yellow warning, orange warning, and red warning.

[0035] Furthermore, blue, yellow, orange, and red alerts each correspond to a range of crack opening / closing values. When the calculated crack opening / closing value falls within a certain range, a corresponding alert is issued based on the alert level corresponding to that range.

[0036] Compared with existing technologies, the beneficial effects of adopting the above technical solution are as follows:

[0037] Under different surface changes, this method can predict and issue early warnings for different levels of landslide disasters, thus solving the problem of landslide prevention and mitigation. Attached Figure Description

[0038] Figure 1This is a flowchart illustrating a method for monitoring and early warning of geological disasters caused by landslides along oil and gas pipelines, as provided in this embodiment.

[0039] Figure 2 This is a schematic diagram of the physical force model of the collapsed slope in this embodiment.

[0040] Figure 3 This is a schematic diagram of the stress analysis in the plastic zone.

[0041] Figure 4 This is a schematic diagram of the state when the center of gravity of the rock mass deviates from the centroid. Detailed Implementation

[0042] The present invention will now be further described with reference to the accompanying drawings.

[0043] like Figure 1 As shown in the figure, this embodiment provides a method for monitoring and early warning of geological disasters such as landslides along oil and gas pipelines. The method includes the following steps:

[0044] Step 1: Model and analyze the collapsed slope to determine that the collapsed slope includes the rock mass that has collapsed and the slope surface that has not collapsed. The bottom of the collapsed rock mass is a plastic zone.

[0045] Specifically, in this embodiment, such as Figure 2 As shown, the rock mass is represented by a parallelogram ABCD. The rock mass surface AD ​​is completely parallel to the slope surface BC (α = β). It is assumed that the huge self-weight of the potential collapse rock mass ABCD puts the soft rock at its bottom in a plastic state. The plastic zone is represented by the triangle ABE at the bottom, thus completing the modeling of the collapse slope.

[0046] Step 2: Obtain the self-weight of the rock mass, the anti-sliding force of the rock mass on the slope, and the sliding force of the rock mass. Analyze the pressure from the rock mass on the plastic zone when a collapse occurs, and simulate the opening and closing degree of cracks between the rock mass and the slope.

[0047] Specifically, in this embodiment, such as Figure 1 As shown, the rock mass BCDE in the upper part of the plastic zone is hard rock and in an elastic state. Its self-weight G is:

[0048]

[0049] Where G represents the self-weight of the rock mass (kN), S BCDE This represents the area (m²) of the rock mass after the plastic zone has been removed. 2 ), where γ represents the unit weight of the rock mass (kN / m³). 3 ), where a represents the horizontal width of the rock mass (m), H represents the height of the collapse slope (m), and α represents the slope of the collapse rock mass (°);

[0050] According to the classical mechanics formula, the anti-slip force R on the BC surface is calculated as follows: φ yes:

[0051] R φ =λtanφ·G cosα (2)

[0052] Among them, R φ λ represents the sliding resistance (kN), φ represents the internal friction angle of the rock mass (°), λ represents the contact coefficient (0.75), G represents the self-weight of the rock mass (kN), and α represents the slope of the collapsed rock mass (°).

[0053] The sliding force T is:

[0054] T = G sinα (3)

[0055] Where T represents the sliding force (kN), α represents the slope of the collapsed rock mass (°), and G represents the self-weight of the rock mass (kN);

[0056] Then, further analysis and calculation yielded the effective pressure (TR) acting on the top surface BE of the plastic zone. φ ), expressed in terms of stress as:

[0057]

[0058] Among them, S BE σ1 represents the length (m) of the top surface of the plastic zone, σ1 represents the stress (MPa), and T represents the sliding force (kN);

[0059] The stress state of the plastic zone is as follows Figure 3 As shown:

[0060] Figure 3 In the plastic zone, the maximum principal stress σ1 and the minimum principal stress σ3 are respectively:

[0061]

[0062] As the geological movement intensifies, the dip angle of the rock mass increases. The insufficient self-supporting capacity of the top plate in the plastic zone inevitably leads to bending and subsidence of the top plate, gradually developing into a dangerous area. The overlying hard rock subsides, causing tensile cracks on the structural plane BC, significantly reducing λ and thus increasing R. φ The pressure on BE decreases due to factors such as dissolution, the intrusion of other rocks, and the filling of water, which cause fissure water pressure. Therefore, σ1 increases.

[0063] At this point, according to the plasticity condition, if the stress in the plastic zone satisfies the yield condition, then the rock mass will fail. That is:

[0064]

[0065] Where σ1 represents stress (MPa), denoted by , where is the internal friction angle of the rock mass in the plastic zone (°), and c represents the cohesion of the rock mass in the plastic zone (MPa).

[0066] By integrating equations (4), (5), and (6) and substituting them into equation (1), we can derive the relationship between the critical angle of inclination α0 for maintaining slope stability and the slope height H:

[0067]

[0068] Where H represents the height of the collapsed slope (m), and c represents the cohesion of the rock mass in the plastic zone (MPa). γ represents the internal friction angle (°) of the rock mass in the plastic zone, and γ represents the unit weight of the rock mass (kN / m³). 3 ), φ represents the internal friction angle of the rock mass (°), α0 represents the critical dip angle for the slope to remain stable (°), a represents the horizontal width of the rock mass (m), and λ represents the contact coefficient (0.75);

[0069] After a slope collapses and becomes unstable, it enters a stage of toppling failure with the plastic zone as the turning point. The rock mass separates from the slope surface, and cracks gradually extend deeper in the vertical direction. At this point, the rock mass is only affected by gravity, such as... Figure 3 As shown, the crack opening degree at this time is as follows:

[0070]

[0071] Where L0 represents the crack opening degree (m), H represents the slope height (m), β represents the slope of the collapsed rock mass (°), and α0 represents the critical dip angle for the slope to remain stable (°).

[0072] The opening and closing of cracks can be used to observe the state of the rock mass and determine whether it will collapse.

[0073] Step 3: Combine the crack opening degree to create an early warning level, and issue an early warning of the corresponding level based on the specific crack opening degree value.

[0074] Specifically, in this embodiment, through multiple sets of data fitting analysis and case verification, in order to ensure the effectiveness of the collapse disaster early warning value, based on the experience of the empirical curve method and the mechanical analysis method, combined with a large amount of classical collapse data critical data analysis, and in accordance with the geological disaster meteorological early warning classification formulated by the Ministry of Land and Resources and the China Meteorological Administration, combined with the numerical range of crack opening and closing degree, the early warning level of this method is obtained, as shown in Table 1.

[0075] Table 1 Classification of Landslide Disaster Early Warning Levels

[0076] Warning Level Blue Alert Yellow Alert Orange alert Red Alert Crack opening degree 0.5～0.8m 0.8～1.1m 1.1～1.5m >1.5m

[0077] Based on the actual geographical conditions, the crack opening degree between the rock mass and the slope surface is determined. The specific crack opening degree value is used to determine the current warning level and issue corresponding warning information.

[0078] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein. Any non-substantial changes or modifications made by those skilled in the art without departing from the spirit of this invention should fall within the scope of the claims.

Claims

1. A method for monitoring and early warning of geological disasters such as landslides along oil and gas pipelines, characterized in that, include: Step 1: Model and analyze the collapsed slope to determine that the collapsed slope includes the rock mass that has collapsed and the slope surface that has not collapsed. The bottom of the collapsed rock mass is a plastic zone. Step 2: Obtain the self-weight of the rock mass, the anti-sliding force of the rock mass on the slope surface, and the sliding force of the rock mass. Analyze the pressure from the rock mass on the plastic zone when a collapse occurs, and simulate the crack opening degree between the rock mass and the slope surface. Step 3: Combine the crack opening degree to create an early warning level, and issue an early warning of the corresponding level based on the specific crack opening degree value; Step 2 specifically includes: Step 21: Obtain the self-weight of the rock mass G The specific formula is as follows: （1） in, G This indicates the rock mass's self-weight (kN). This represents the area (m²) of the rock mass after the plastic zone has been removed. 2 ), This indicates the unit weight of the rock mass (kN / m³). 3 ), Indicates the horizontal width (m) of the rock mass. H Indicates the height (m) of the collapsed slope. Indicates the slope (°) of the collapsed rock mass; Step 22: Obtain the anti-sliding force of the rock mass on the slope surface The specific formula is as follows: （2） in, This indicates the anti-slip force (kN). Indicates the internal friction angle (°) of the rock mass. λ This represents the contact coefficient (0.75). Obtaining the sliding force of the rock mass T The specific formula is as follows: （3） in, T This represents the sliding force (kN). G This indicates the rock mass's self-weight (kN). Indicates the slope (°) of the collapsed rock mass; Step 23: Based on the obtained anti-slip force and sliding force T Further analysis was conducted on the effective pressure on the top surface of the plastic zone, and stress was used as the basis for analysis. The form is expressed as follows: （4） in, Indicates stress, This indicates the length (m) of the top surface of the plastic zone. T This represents the sliding force (kN). Indicates anti-slip force (kN); Step 24: Based on the plasticity condition, determine the stress that should be satisfied when the rock mass collapses. The critical conditions are as follows: （5） in, Indicates stress (MPa). Indicates the internal friction angle (°) of the rock mass in the plastic zone. c This represents the cohesion of the rock mass in the plastic zone (MPa). Step 25: By integrating equations (4) and (5) and substituting them into equation (1), the critical angle for maintaining slope stability can be obtained. The relationship between the slope height H and the slope surface height is as follows: （6） in H Indicates the height (m) of the collapsed slope. c This represents the cohesion (MPa) of the rock mass in the plastic zone. Indicates the internal friction angle (°) of the rock mass in the plastic zone. This indicates the unit weight of the rock mass (kN / m³). 3 ), Indicates the internal friction angle (°) of the rock mass. α 0 represents the critical angle of inclination (°) at which the slope remains stable. Indicates the horizontal width (m) of the rock mass. λ This represents the contact coefficient (0.75). Step 26: The crack opening degree L0 between the slope surface and the rock mass is obtained as follows: （7） in, L 0 indicates the crack opening degree (m). H β represents the slope height (m), and β represents the slope of the collapsed rock mass (°). α 0 represents the critical angle of inclination (°) at which the slope remains stable.

2. The monitoring and early warning method for geological disasters caused by landslides along oil and gas pipelines according to claim 1, characterized in that, Step 1, specifically the modeling and analysis of the collapsed slope, includes: Based on the geological conditions of actual landslides, the landslide slope is simplified into a trapezoid, the landslide rock mass into a parallelogram, and the plastic zone into a triangle, thus constructing a physical force model of the landslide slope.

3. The monitoring and early warning method for geological disasters caused by landslides along oil and gas pipelines according to claim 1, characterized in that, Step 3, which involves determining the warning level based on the crack opening degree, includes the following steps: Based on the geological disaster meteorological early warning classification formulated by the Ministry of Land and Resources and the China Meteorological Administration, and combined with the numerical range of crack opening degree, the early warning level is formulated.

4. A monitoring and early warning method for geological disasters caused by landslides along oil and gas pipelines, as described in claim 3, is characterized in that... The warning levels include four levels: blue warning, yellow warning, orange warning, and red warning.

5. A monitoring and early warning method for geological disasters caused by landslides along oil and gas pipelines according to claim 4, characterized in that, Blue, yellow, orange, and red alerts each correspond to a range of crack opening values. When the calculated crack opening value falls within a certain range, a corresponding alert is issued based on the alert level corresponding to that range.

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