A method for highway risk assessment and rescue channel optimization after a strong earthquake

Abstract

The present invention discloses a method for evaluating the risk of highways after a strong earthquake and optimizing rescue channels, and the steps include: S1, solving the slope displacement according to the geometric properties of the highway slope, the physical and mechanical parameters of the rock and soil body, and the seismic acceleration data of the corresponding area, S2, comparing the slope displacement with the critical displacement of the regional highway slope for geological disasters, and judging the susceptibility of geological disasters; S3, calculating the initial efficiency of the existing road network according to the highway network topology model of the region, and adjusting the connectivity configuration in the road network based on this, so as to calculate the severity of the consequences when a single line or node is damaged, S4, adjusting according to the post-disaster site information, and then establishing a risk matrix according to the severity of the consequences and the susceptibility of the geological disasters to perform risk evaluation of each line in the regional road network, and obtaining the optimal selection of the rescue channel. The present invention can simultaneously consider the problems of regional geological disaster susceptibility and road network toughness, and select the optimal rescue channel.

Description

Technical Field

[0001] The present invention relates to the field of risk analysis of path selection in engineering geological slope disaster prevention and control, and in particular to a method for risk assessment of highways after a strong earthquake and for optimizing rescue channels. Background Art

[0002] The western part of my country is dominated by tectonic erosion of mid- and high-mountain landforms, especially in the transition zone from the Sichuan Basin to the Yunnan-Guizhou Plateau and the Sichuan-Tibet Plateau. Due to tectonic uplift and river cutting, significant deep canyon landforms have been formed. Geological disasters frequently occur under the influence of surface runoff scouring, earthquakes, and engineering excavation disturbances. Mountain roads are long and low-density, and geological disasters often lead to traffic paralysis on the roads where they are located, seriously affecting disaster relief and travel.

[0003] Existing disaster investigation methods include manual ground verification, drone technology, 3D laser scanning, radar remote sensing and time-series InSAR (synthetic aperture radar interferometry), etc. For example, Chinese invention patent application CN103399344A discloses a method for predicting the location of landslide disasters after an earthquake, and Chinese invention patent application CN118583971A discloses a method and device for monitoring and evaluating the stability of highway slopes, wherein the method obtains vibration data at a preset position of the highway slope to be monitored; processes the vibration data, calculates the change in the elastic wave velocity of the slope medium of the highway slope to be monitored; and evaluates the stability of the highway slope based on the change in the elastic wave velocity of the slope medium of the highway slope to be monitored.

[0004] Existing methods for evaluating the efficiency of transportation networks, such as the Chinese invention patent CN115169771B, disclose a method for quickly evaluating the efficiency of transportation networks affected by flood disasters, including obtaining rainfall forecast results; extracting the flood inundation range; establishing a geological disaster risk background field for the rainfall area within the flood inundation range; identifying the affected areas affected by the flood disaster and the results of the flood disaster on the affected areas; fusing the results of the flood disaster on the affected areas with the transportation network data for analysis, and obtaining information on the scale and degree of road damage and obstruction caused by the flood disaster in the affected areas. For example, Chinese invention patent CN109740898B discloses a road network reliability assessment method, which obtains the geospatial location data, road data and historical geological disaster data of the road sections in the area to be assessed; constructs a road complex network model based on the acquired geospatial location data and road data; constructs different types of disaster scenario interference patterns based on the historical geological disaster data; simulates and attacks the road complex network model with different types of disaster scenario interference patterns; analyzes and calculates the overall network connectivity and network efficient connectivity of the road complex network model in the initial state and the simulated attack state, and evaluates the reliability of the road sections in the area to be assessed based on the importance of the road sections, the relative decrease rate of the maximum connected subgraph size and the relative decrease rate of the whole network connectivity efficiency.

[0005] However, the risk assessment of highways after a strong earthquake is in urgent need of immediate action, and existing technical means cannot meet the actual needs of disaster rescue. Among them, the evaluation of geological disaster susceptibility has not been effectively combined with the risk assessment of highway geological disasters after a disaster, especially the weak nodes of geological disaster-bearing bodies in the regional highway network and the degree of influence of different nodes on the regional highway network, which plays an important supporting role in the risk assessment of regional highways after a disaster and the optimization of rescue channels. Summary of the invention

[0006] The purpose of the present invention is to solve the above-mentioned shortcomings and propose a method for risk assessment of highways after a strong earthquake and optimization of rescue channels, which solves the problem that the existing risk assessment methods for highways after a strong earthquake fail to simultaneously consider the susceptibility to regional geological disasters and the resilience of the road network. A method for risk assessment of highways after a strong earthquake and optimization of rescue channels based on the susceptibility to regional geological disasters and the resilience of the road network is proposed to solve the technical difficulties in the risk assessment of geological disasters on highways in mountainous areas after a strong earthquake.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] A method for risk assessment of highways after a strong earthquake and optimal selection of rescue channels, comprising the following steps:

[0009] S1. Determine the displacement of the slope according to the geometric properties of the highway slope, the physical and mechanical parameters of the rock and soil mass, and the seismic acceleration data of the corresponding area. In the absence of seismic acceleration data of the highway slope, the Newmark displacement model is used to determine the displacement of the slope in the area.

[0010] S2, comparing the slope displacement with the critical displacement of the highway slope in the area for geological disasters to determine the susceptibility of geological disasters to occur;

[0011] S3. Calculate the initial performance of the existing road network based on the road network topology model of the region, and adjust the connectivity configuration in the road network based on this to calculate the severity of the consequences when a single line or node is damaged, wherein the road network topology model includes the road network, road length and population density of the region;

[0012] S4. Based on the post-disaster on-site information feedback, the roads with serious damage that affects traffic are removed from the road network. Then, based on the severity of the consequences and the susceptibility of the geological disasters, a risk matrix is ​​established to conduct risk assessment of each line in the regional road network, select the path with the lowest loss, and obtain the optimal choice of rescue channel.

[0013] The preferred technical solutions of the present invention are as follows:

[0014] Preferably, step S1 comprises the following steps:

[0015] S11. Determine the slope stability coefficient F by using the geometric properties of the highway slope and the physical and mechanical parameters of the rock and soil mass. s ,

[0016]

[0017] Among them, the slope geometric attributes include the slope rock and soil layer thickness t, saturation S r and slope foot α; the physical and mechanical parameters of rock and soil include effective cohesion c', internal friction angle φ, rock and soil weight γ and groundwater weight γ w ;

[0018] S12, according to the slope stability coefficient F s , the critical acceleration a of the potential sliding body of the highway slope is calculated by the quasi-static method according to the infinite slope model c ,

[0019]

[0020] Among them, g is the acceleration of gravity, β is the inclination angle of the rock layer sliding surface;

[0021] S13, the earthquake acceleration a is greater than the critical acceleration a c The part of the slope is integrated twice over time to obtain the slope displacement, as follows:

[0022]

[0023] Among them, D n is the slope displacement, t is the time, and v(t) is the intermediate function;

[0024] When the records of the road slope ground acceleration a are lacking, the simplified Newmark displacement model based on statistical analysis is used to determine the Newmark displacement distribution in the study area, as follows:

[0025]

[0026] Where: I a For Arias strength; D f is the earthquake fault distance; D n is the slope displacement.

[0027] Preferably, the slope foot α is used as β as the inclination angle of the rock stratum sliding surface.

[0028] Preferably, S2 is to set the critical displacement of the highway slope in the area for geological disasters in combination with the historical geological disaster information in the area.

[0029] Preferably, the risk matrix in S4 is as follows.

[0030]

[0031] Preferably, the early earthquake damage data of the area is processed according to S1 to S4 to obtain the optimal choice of road network risk assessment and rescue channel before the disaster. Due to the uniqueness of earthquake occurrence, using the early earthquake damage data of the same area to calculate the permanent displacement of the slope, and then establishing the road network risk assessment and rescue channel is a pre-disaster application, which can provide an assessment of the resilience of the road network in the current area during earthquake disasters, which is beneficial to the preparation of the risk assessment matrix and facilitates rapid risk assessment after the earthquake.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: It solves the problem that the existing post-strong earthquake highway risk assessment method fails to consider both the regional geological disaster susceptibility and road network resilience. It proposes a post-strong earthquake highway risk assessment and rescue channel optimization method based on the regional geological disaster susceptibility and road network resilience, solving the technical difficulties of post-strong earthquake highway geological disaster risk assessment in mountainous areas. It provides technical means for emergency repair and rapid maintenance of highways in western mountainous areas after strong earthquakes, which is beneficial to ensuring the safety of personnel and property in engineering construction.

[0033] In some preferred embodiments of the present invention, based on historical geological disaster information, the disaster susceptibility assessment of the road network is more accurate, and a risk matrix for risk assessment is proposed to quickly conduct risk assessment, provide strong support for the optimization of rescue channels, and meet the needs of rapid response during emergency and disaster relief. At the same time, the selected rescue channels take into account the resilience of the road network, and are not prone to traffic paralysis due to aftershocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of an embodiment of a method for risk assessment of highways after a strong earthquake and for selecting rescue channels according to the present invention.

[0035] Figure 2 It is a distribution diagram of calculation results of static stability coefficient of highway slope in an embodiment of a method for risk assessment of highway and optimization of rescue channels after a strong earthquake of the present invention.

[0036] Figure 3 It is a distribution diagram of calculation results of critical acceleration of highway slopes in an embodiment of a method for risk assessment of highways after a strong earthquake and optimization of rescue channels of the present invention.

[0037] Figure 4 It is an Arias intensity distribution diagram of earthquakes in a certain area in an embodiment of a method for risk assessment of highways after a strong earthquake and optimization of rescue channels according to the present invention.

[0038] Figure 5 This is a Newmark displacement calculation result diagram of a highway slope in a certain area in an embodiment of a method for risk assessment of highways after a strong earthquake and optimization of rescue channels of the present invention.

[0039] Figure 6 It is a regional road network distribution map of an embodiment of a method for post-strong earthquake highway risk assessment and rescue channel optimization according to the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention.

[0041] like Figure 1 As shown, a method for risk assessment of highways after a strong earthquake and selection of rescue channels is provided. The steps include:

[0042] S1. Solve the slope stability coefficient Fs through the geometric properties of the highway slope and the physical and mechanical parameters of the rock and soil. The geometric properties of the slope include the thickness of the rock and soil layer t, the saturation S r and slope foot α; the physical and mechanical parameters of rock and soil include effective cohesion c', internal friction angle φ, rock and soil weight γ and groundwater weight γ w Based on this, the slope stability coefficient F is solved s as follows:

[0043] (1)

[0044] Figure 2 The figure shows the slope stability coefficient F of some areas selected in western Sichuan based on S2. s The distribution diagram of the calculation results.

[0045] S2. Combined with the slope stability coefficient, the critical acceleration a of the potential sliding body of the highway slope is calculated by the quasi-static method according to the infinite slope model. c , as shown in formula (2):

[0046] (2)

[0047] Among them, g is the acceleration of gravity, β is the inclination angle of the rock layer sliding surface. In order to simplify the model, the slope foot α mentioned above can be used to replace the inclination angle β of the rock layer sliding surface;

[0048] Figure 3 Shown is the distribution map of the calculation results of critical acceleration of highway slopes based on S3 in some areas selected in western Sichuan.

[0049] S3. Collect complete records of earthquake acceleration on the road slopes in the study area and convert the earthquake acceleration a greater than the critical acceleration a c The part of the slope is integrated twice over time to obtain the permanent displacement of the slope, which is as follows:

[0050] (3)

[0051] Among them, D n is the slope displacement, in cm, and v(t) is the intermediate function;

[0052] When the records of the road slope ground acceleration a are lacking, the simplified Newmark displacement model based on statistical analysis is used to determine the Newmark displacement distribution in the study area. The formula is as follows:

[0053] (4)

[0054] Where: I a is the Arias intensity, in m / s; D f is the distance of the seismogenic fault, unit: km; D n is the Newmark displacement value, i.e. the slope displacement, in cm;

[0055] Figure 4 This is the Arias intensity distribution map of earthquakes in a certain area of ​​western Sichuan after a strong earthquake. Figure 5 This is the Newmark displacement calculation result diagram of the highway slope in this area.

[0056] S4. Combined with the historical geological disaster information of the study area, the critical displacement x of the road slope in the study area for geological disasters is set, in cm, and compared with D n The relative size of and x is used to identify the geological disasters on the highway slope, that is, to determine whether landslides occur and their susceptibility. The rules are:

[0057] (5).

[0058] S5. Statistical information on regional highway networks, highway lengths, and population density is collected to calculate the initial performance of the existing road network based on the network topology model, that is, the impact of a highway interruption. Based on this, the connectivity configuration in the road network is adjusted to improve network performance, so as to calculate the path with the lowest loss, thereby supporting regional road network planning and resilience improvement. Figure 6 As shown, it is a road network topology model diagram of a certain area in the prior art.

[0059] S6. After the earthquake occurs, the geological disasters on the slopes of each highway in the regional road network are predicted through the steps described in S1 to S3, and the susceptibility of landslides on the slopes of each highway in the road network is evaluated; the severity of the consequences when a single line or node in the regional road network is damaged is calculated based on the network topology model described in S5; the risk of each line in the regional road network is evaluated based on the risk matrix to obtain the risk evaluation results.

[0060] S7. Based on the risk assessment results in S6 and combined with post-disaster on-site information feedback, the roads with severe damage that affects traffic are removed from the road network, and then the lowest loss path is selected to obtain the optimal choice of rescue channel.

[0061] In the above embodiment, a further preferred technical solution is: in step S6, the recommended risk matrix is ​​shown in the following table.

[0062]

[0063] Based on the above embodiment, the early earthquake damage data (i.e., historical earthquake damage data) of the area to be evaluated can also be processed according to S1 to S7 in the above embodiment to obtain the optimal selection of road network risk assessment and rescue channels before the disaster. Due to the uniqueness of earthquake occurrence, using the early earthquake damage data in the same area to calculate the permanent displacement of the slope and then establish the road network risk assessment and rescue channel is preferably a pre-disaster application, which can provide an assessment of the resilience of the road network in the current area during earthquake disasters, is beneficial to prepare a risk assessment matrix, and facilitates rapid risk assessment after the earthquake.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for risk assessment of highways after a strong earthquake and optimal selection of rescue channels, comprising the following steps: S1. Determine the displacement of the slope according to the geometric properties of the highway slope, the physical and mechanical parameters of the rock and soil mass, and the seismic acceleration data of the corresponding area. In the absence of seismic acceleration data of the highway slope, the Newmark displacement model is used to determine the displacement of the slope in the area. S2, comparing the slope displacement with the critical displacement of the highway slope in the area for geological disasters to determine the susceptibility of geological disasters to occur; S3. Calculate the initial performance of the existing road network based on the road network topology model of the region, and adjust the connectivity configuration in the road network based on this to calculate the severity of the consequences when a single line or node is damaged, wherein the road network topology model includes the road network, road length and population density of the region; S4. Based on the post-disaster on-site information feedback, the roads with serious damage that affects traffic are removed from the road network. Then, based on the severity of the consequences and the susceptibility of the geological disasters, a risk matrix is ​​established to conduct risk assessment of each line in the regional road network, select the path with the lowest loss, and obtain the optimal choice of rescue channel.

2. The method for post-strong earthquake highway risk assessment and rescue channel optimization according to claim 1, characterized in that: The S1 step includes the following steps: S11. Determine the slope stability coefficient F by using the geometric properties of the highway slope and the physical and mechanical parameters of the rock and soil mass. s , Among them, the slope geometric attributes include the slope rock and soil layer thickness t, saturation S r and slope foot α; the physical and mechanical parameters of rock and soil include effective cohesion c', internal friction angle φ, rock and soil weight γ and groundwater weight γ w ; S12, according to the slope stability coefficient F s , the critical acceleration a of the potential sliding body of the highway slope is calculated by the quasi-static method according to the infinite slope model c , Among them, g is the acceleration of gravity, β is the inclination angle of the rock layer sliding surface; S13, the earthquake acceleration a is greater than the critical acceleration a c The part of the slope is integrated twice over time to obtain the slope displacement, as follows: Among them, D n is the slope displacement, t is the time, and v(t) is the intermediate function; When the records of the road slope ground acceleration a are lacking, the simplified Newmark displacement model based on statistical analysis is used to determine the Newmark displacement distribution in the study area, as follows: Where: I a For Arias strength; D f is the earthquake fault distance; D n is the slope displacement.

3. The method for post-strong earthquake highway risk assessment and rescue channel optimization according to claim 2, characterized in that: Use the slope toe α as the inclination angle of the rock sliding surface and β as the inclination angle of the rock sliding surface.

4. The method for post-strong earthquake highway risk assessment and rescue channel optimization according to claim 3, characterized in that: S2 is to set the critical displacement of the highway slope in the area for geological disasters in combination with the historical geological disaster information in the area.

5. The method for post-earthquake highway risk assessment and rescue channel optimization according to claim 4, characterized in that: The risk matrix in S4 is as follows 。 6. The method for post-strong earthquake highway risk assessment and rescue channel optimization according to claim 5, characterized in that: The early earthquake damage data of the area is processed according to S1 to S4 to obtain the pre-disaster road network risk assessment and the optimal selection of rescue channels.

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