A monitoring and early warning system for secondary collapse of buildings under aftershocks

Abstract

The application relates to a secondary collapse monitoring and early warning system for a building under aftershock, which comprises a building structure monitoring module and an early warning module; the building structure monitoring module comprises a plurality of sensors, the sensors are installed at local collapse building target monitoring points, and are used for monitoring the structural response of the local collapse building under aftershock; the early warning module is provided with a dynamic early warning threshold algorithm, different initial early warning thresholds are set according to the characteristic collapse mode of the local collapse building on site, and accurate and timely early warning is provided after data screening processing and sensitivity analysis are carried out by collecting aftershock source signals and structural response signals, meanwhile, the collapse early warning threshold is dynamically updated and is used for collapse judgment and early warning next time. Compared with the prior art, the application considers two factors of aftershock and structural response, and through the dynamic iterative early warning threshold, the monitoring and early warning of the secondary collapse of the building can be more scientific and accurate.

Description

Technical Field

[0001] This invention relates to the field of earthquake on-site rescue technology, and in particular to a monitoring and early warning system for secondary building collapse under aftershocks. Background Technology

[0002] Buildings that collapse locally after the main shock may experience secondary collapse under aftershocks, posing a significant danger and challenge to rescuers searching for buried individuals. Currently, in my country, earthquake rescue operations typically rely on safety officers for on-site supervision. They assess secondary collapse based on their experience and real-time observation of the site, or use theodolites to monitor displacement changes in the collapsed structure for early warning. However, neither method can quickly and accurately determine whether a building has experienced secondary collapse under aftershocks. Internationally, sensor devices are often used to monitor the response of collapsed structures, such as displacement, velocity, and acceleration. However, this method cannot accurately provide a warning threshold for the structural response, or the given threshold may be too high or too low, often resulting in alarms that do not match the actual state of the building. For example, an alarm may sound even when the building has not collapsed, causing repeated psychological panic among rescue personnel. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a secondary collapse monitoring and early warning system for buildings under aftershocks. This system monitors the structural response of partially collapsed buildings during aftershocks, sets corresponding initial early warning thresholds for different collapse modes, and iteratively updates the early warning thresholds by monitoring the building collapse status after each aftershock, thereby achieving more accurate early warnings that are more in line with reality.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A monitoring and early warning system for secondary building collapse under aftershocks, the system is connected to earthquake monitoring stations and includes a building structure monitoring module and an early warning module;

[0006] The building structure monitoring module and the early warning module are connected;

[0007] The building structure monitoring module includes multiple sensors, which are installed at the target monitoring points of the partially collapsed building. The sensors are used to monitor the structural response of the partially collapsed building under aftershocks.

[0008] The early warning module issues an early warning based on the structural response signal detected by the building structure monitoring module.

[0009] Furthermore, the structural response includes displacement response, velocity response, and acceleration response.

[0010] Furthermore, the sensor is a wireless sensor.

[0011] Furthermore, the early warning module is equipped with a sensitivity analysis method for identifying active data, amplifying key data, and reducing noise in key data of the structural response signals transmitted from the building structure monitoring module.

[0012] Furthermore, the early warning module is connected to an aftershock source signal data receiving device, which is used to acquire aftershock source signal data measured by earthquake monitoring stations.

[0013] Furthermore, the early warning module is equipped with an initial early warning threshold group and a dynamic early warning parameter threshold algorithm, which are used to analyze the aftershock source signal and the structural response signal and issue early warnings in real time, while dynamically adjusting the early warning threshold.

[0014] Furthermore, the initial warning threshold group is a set of corresponding initial warning thresholds set based on previous experiments for different initial local collapse modes.

[0015] Furthermore, the initial value of the warning threshold is obtained from the initial warning threshold group based on the characteristic collapse pattern of the partially collapsed building on site.

[0016] Furthermore, the warning parameters included in the dynamic warning parameter threshold algorithm are the P-wave signal strength and the warning threshold. The P-wave signal strength is a necessary condition for generating a warning signal, and the warning threshold is a sufficient condition for generating a warning signal.

[0017] Furthermore, the dynamic early warning parameter threshold algorithm includes the following execution steps:

[0018] S1. When the first aftershock occurs, the intensity of the P-wave signal Ms(1) measured by the seismic monitoring station is obtained. At the same time, the structural response of the target point of the collapsed structure is monitored. If the first structural response monitoring data exceeds the initial warning threshold TH, the first warning is issued; otherwise, no warning is issued.

[0019] S2. Determine whether the target point of the collapsed structure has collapsed a second time after the first warning. If not, set the second warning threshold to TH+1.

[0020] S3. When the second aftershock occurs, the intensity of the P-wave signal measured by the seismic monitoring station is obtained. If it is less than Ms(1), no alarm is generated; otherwise, the intensity of the P-wave signal is recorded as Ms(2). Then, the structural response of the target point of the collapsed structure is monitored. If the second structural response monitoring data exceeds the second warning threshold TH+1, a second warning is issued; otherwise, no warning is issued.

[0021] S4. Determine whether the target point of the collapsed structure has collapsed a second time after the second warning. If not, set the third warning threshold to TH+1+1.

[0022] S5. When the third aftershock occurs, the intensity of the P-wave signal measured by the seismic monitoring station is obtained. If it is less than Ms(2), no alarm is generated; otherwise, the intensity of the P-wave signal is recorded as Ms(3). The response of the target monitoring point is then analyzed. If the third structural response monitoring data exceeds the third warning threshold TH+1+1, a third warning is issued; otherwise, no warning is issued.

[0023] S6. Determine whether the target point of the collapsed structure has collapsed a second time after the third warning. If not, set the third warning threshold to TH+1+1+1. Repeat this process until no more aftershocks occur.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention utilizes aftershock source signal data measured by seismic monitoring stations to monitor the structural response of partially collapsed buildings during aftershocks. For different characteristic collapse modes, corresponding initial warning thresholds are set for secondary collapse warnings. Furthermore, after each aftershock, the warning thresholds are iteratively updated by monitoring the building's collapse status, achieving more accurate and realistic warnings. This invention enables dynamic and precise real-time monitoring and warning of partially collapsed buildings under aftershock conditions. By continuously iterating and updating the aftershock P-wave signal intensity and warning thresholds, it avoids the many drawbacks of relying on experience and real-time observation of on-site conditions, or using theodolites to observe displacement changes in collapsed structures, which has been a long-standing practice in my country. It also provides a scientific and reasonable method to address the deficiency of using sensor devices to monitor the response of collapsed structures and obtain accurate warning thresholds. Attached Figure Description

[0026] Figure 1 This is a flowchart of the present invention;

[0027] Figure 2 This is a schematic diagram of the system framework of the present invention. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0029] Example 1

[0030] In the description of this embodiment, the following terms need to be understood: Ms represents the intensity of the aftershock P-wave signal, Ms+1… indicates that the intensity of the aftershock P-wave signal increases step by step; TH represents the initial warning threshold, TH+1… indicates that the warning threshold increases step by step, and the initial threshold TH is obtained from the initial warning threshold group according to the characteristic collapse mode of the locally collapsed building; P-wave is a longitudinal wave, which is vertical shaking, and S-wave is a transverse wave, which is horizontal shaking and is the main cause of building collapse. P-wave propagation speed is faster than S-wave; N represents the number of aftershocks, assuming that a maximum of 100 aftershocks will occur during the rescue process; j represents the variable of the number of aftershocks N.

[0031] Appendix Figure 1-2 The flowchart and schematic diagram of a monitoring and early warning system for secondary building collapse under aftershocks are described.

[0032] This invention proposes a monitoring and early warning system for secondary building collapse under aftershocks. The system is installed at the rescue site after the main shock and consists of a building structure monitoring module and an early warning module. The early warning module is connected to the aftershock source signal of the earthquake monitoring station and the structural response signal of the building structure monitoring module.

[0033] The building structure monitoring module includes multiple sensors, which are installed at the target monitoring points of the partially collapsed building. The sensors are used to monitor the structural response of the partially collapsed building under aftershocks. The early warning module issues early warnings based on the structural response signals monitored by the building structure monitoring module.

[0034] The structural response includes displacement response, velocity response, and acceleration response. Preferably, the sensor used in this embodiment is a wireless sensor.

[0035] In this embodiment, the early warning module incorporates a sensitivity analysis method for identifying active data, amplifying key data, and reducing noise in key data from the structural response signals transmitted by the building structure monitoring module. Simultaneously, the early warning module is connected to an aftershock source signal data receiving device, which acquires aftershock source signal data measured by earthquake monitoring stations. The early warning module also includes an initial early warning threshold set and a dynamic early warning parameter threshold algorithm for analyzing aftershock source signals and structural response signals, providing real-time early warnings, and dynamically adjusting the early warning thresholds.

[0036] The initial warning threshold set is a collection of corresponding initial warning thresholds set based on previous experiments for different initial local collapse modes. The initial values ​​of the warning thresholds are obtained from the initial warning threshold set according to the characteristic collapse modes of the partially collapsed buildings on site, and are used for the first aftershock warning after the system is installed.

[0037] The dynamic early warning parameter threshold algorithm includes P-wave signal strength and early warning threshold as early warning parameters. P-wave signal strength is a necessary condition for generating an early warning signal, and early warning threshold is a sufficient condition for generating an early warning signal.

[0038] In this embodiment, the earthquake monitoring station and the on-site early warning module are equipped with associated wireless transmission devices. First, after the earthquake ruptures at the epicenter, P-waves and S-waves are transmitted in all directions. The P-waves arrive at the station first and are recorded by the strong-motion seismometer. Then, the measured aftershock intensity data is transmitted wirelessly to the early warning module at the earthquake rescue site.

[0039] Specifically, the building structure monitoring module installs wireless sensors for displacement, velocity, and acceleration at target monitoring points of collapsed buildings at the earthquake site. When the collapsed structure is subjected to aftershocks, the structural response signals generated by the sensors are transmitted to the early warning module.

[0040] Specifically, the target monitoring points are installed on the intact structure above the collapsed layer. The safety officer at the earthquake search and rescue site selects at least three monitoring points according to the actual situation. The sensors at each monitoring point use wireless transmission and can simultaneously record the time history response of structural displacement, velocity, and acceleration, and transmit the response signals to the early warning module in real time.

[0041] Specifically, the dynamic early warning parameter threshold algorithm built into the early warning module is programmed using MATLAB software. This algorithm takes into account the dynamic early warning threshold. Once the P-wave signal intensity of the current aftershock exceeds the P-wave signal intensity of the previous aftershock, and the current structural response exceeds the early warning threshold updated in the previous internal program, an alarm is immediately generated. The algorithm specifically includes the following steps:

[0042] After the first aftershock occurs after installation, the monitoring and early warning system receives the P-wave signal intensity Ms(1) transmitted from the earthquake monitoring station. At the same time, it monitors the structural response of the target point of the collapsed structure. If the first structural response exceeds the initial early warning threshold TH, an alarm is generated. If the structure does not collapse a second time after the alarm, the threshold needs to be increased to TH+1.

[0043] When a second aftershock occurs, the monitoring and early warning system receives the intensity of the P-wave signal transmitted from the earthquake monitoring station. If it is less than Ms(1), no alarm is generated. If it is greater than Ms(1), the intensity of the P-wave signal Ms(2) is recorded. The response of the target monitoring point is then analyzed. If the second structural response exceeds the threshold TH+1, an alarm is generated. If the structure does not collapse a second time after the alarm, the threshold needs to be increased to TH+1+1 again.

[0044] When the third aftershock occurs, the monitoring and early warning system receives the intensity of the P-wave signal transmitted from the earthquake monitoring station. If it is less than Ms(2), no alarm is generated. If it is greater than Ms(2), the intensity of the P-wave signal Ms(3) is recorded. The response of the target monitoring point is then analyzed. If the structural response exceeds the threshold TH+1+1, an alarm is generated. If the structure does not collapse after the warning, the threshold needs to be increased to TH+1+1+1.

[0045] The process is repeated iteratively until no more aftershocks occur, at which point the early warning threshold is adaptively adjusted, resulting in more accurate early warnings that better reflect reality.

[0046] Example 2

[0047] In this embodiment, the dynamic early warning parameter threshold algorithm described in the above embodiment was implemented using a MATLAB program. The specific algorithm includes:

[0048]

[0049]

[0050]

[0051] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A monitoring and early warning system for secondary building collapse under aftershocks, characterized in that, The system is connected to earthquake monitoring stations and includes a building structure monitoring module and an early warning module; The building structure monitoring module and the early warning module are connected; The building structure monitoring module includes multiple sensors, which are installed at the target monitoring points of the partially collapsed building. The sensors are used to monitor the structural response of the partially collapsed building under aftershocks. The early warning module issues an early warning based on the structural response signal monitored by the building structure monitoring module. The early warning module is connected to an aftershock source signal data receiving device, which is used to acquire aftershock source signal data measured by earthquake monitoring stations. The early warning module is equipped with an initial early warning threshold group and a dynamic early warning parameter threshold algorithm, which are used to analyze the aftershock source signal and the structural response signal and provide real-time early warning, while dynamically adjusting the early warning threshold. The dynamic early warning parameter threshold algorithm includes early warning parameters such as P-wave signal strength and early warning threshold. The P-wave signal strength is a necessary condition for generating an early warning signal, and the early warning threshold is a sufficient condition for generating an early warning signal. The dynamic early warning parameter threshold algorithm includes the following execution steps: S1. When the first aftershock occurs, the intensity of the P-wave signal Ms(1) measured by the seismic monitoring station is obtained. At the same time, the structural response of the target point of the collapsed structure is monitored. If the first structural response monitoring data exceeds the initial warning threshold TH, the first warning is issued; otherwise, no warning is issued. S2. Determine whether the target point of the collapsed structure has collapsed a second time after the first warning. If not, set the second warning threshold to TH+1. S3. When the second aftershock occurs, the intensity of the P-wave signal measured by the seismic monitoring station is obtained. If it is less than Ms(1), no alarm is generated; otherwise, the intensity of the P-wave signal is recorded as Ms(2). Then, the structural response of the target point of the collapsed structure is monitored. If the second structural response monitoring data exceeds the second warning threshold TH+1, a second warning is issued; otherwise, no warning is issued. S4. Determine whether the target point of the collapsed structure has collapsed a second time after the second warning. If not, set the third warning threshold to TH+1+1. S5. When the third aftershock occurs, the intensity of the P-wave signal measured by the seismic monitoring station is obtained. If it is less than Ms(2), no alarm is generated; otherwise, the intensity of the P-wave signal is recorded as Ms(3). The response of the target monitoring point is then analyzed. If the third structural response monitoring data exceeds the third warning threshold TH+1+1, a third warning is issued; otherwise, no warning is issued. S6. Determine whether the target point of the collapsed structure has collapsed a second time after the third warning. If not, set the third warning threshold to TH+1+1+1. Repeat this process until no more aftershocks occur.

2. The monitoring and early warning system for secondary building collapse under aftershocks according to claim 1, characterized in that, The structural response includes displacement response, velocity response, and acceleration response.

3. The monitoring and early warning system for secondary building collapse under aftershocks according to claim 1, characterized in that, The sensor is a wireless sensor.

4. The monitoring and early warning system for secondary building collapse under aftershocks according to claim 1, characterized in that, The early warning module is equipped with a sensitivity analysis method, which is used to identify active data, amplify key data, and reduce noise in key data of the structural response signals transmitted from the building structure monitoring module.

5. A monitoring and early warning system for secondary building collapse under aftershocks according to claim 1, characterized in that, The initial warning threshold group is a set of corresponding initial warning thresholds set based on previous experiments for different initial local collapse modes.

6. The monitoring and early warning system for secondary building collapse under aftershocks according to claim 1, characterized in that, The initial value of the warning threshold is obtained from the initial warning threshold group based on the characteristic collapse pattern of the partially collapsed building on site.

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