A method and system for early warning of earthquake intensity at key work points during railway construction

Abstract

The present application discloses an earthquake intensity early warning method and system for key construction sites during railway construction, the method comprising: obtaining waveform analysis results corresponding to on-site seismic data; identifying P-wave events of earthquakes at frontier stations according to the waveform analysis results; if the P-wave event of earthquakes at the frontier station triggers an alarm for a single station, the earthquake magnitude of the single station is obtained and the epicenter distance is calculated, and the intensity of the construction site is calculated according to the earthquake magnitude and epicenter distance of the single station; if the P-wave event of earthquakes at the frontier station triggers an alarm for more than two stations, the earthquake magnitude of the double stations is obtained and the double-station earthquake positioning is performed, and the intensity of the construction site is calculated according to the earthquake magnitude of the double stations and the double-station earthquake positioning results; when the intensity value of the construction site exceeds IV degrees, an intensity early warning is issued to the construction site. In this way, a second-level earthquake intensity early warning can be achieved for key construction sites of railway projects under construction, which increases timeliness, improves the accuracy of early warning, and reduces personnel and property losses at the construction site.

Description

Technical Field

[0001] The present invention relates to the field of earthquake early warning, and in particular to an earthquake intensity early warning method and system for key work points during railway construction. Background Art

[0002] Earthquake prevention and disaster reduction is an important livelihood project that concerns the property safety of the people and guarantees social stability and national economic development. my country is one of the countries with the most serious earthquake disasters in the world, with the characteristics of frequent earthquakes, wide distribution, high intensity and severe disasters.

[0003] In recent years, as the world has entered an active earthquake period, frequent earthquakes have not only paralyzed a large number of railway projects in operation, but also posed serious safety threats to railway projects under construction. However, domestic and foreign research on railway earthquake resistance is mainly focused on the operation period. There are few studies and construction of earthquake early warning systems during the construction period of major projects. Only a few studies are conducted on small projects such as bridges and buildings. Other earthquake early warning systems are mainly regional earthquake early warning and alarm systems based on P-wave early warning and intensity rapid reporting. However, the false alarm rate of P-wave early warning is high, and it is impossible to accurately determine the degree of damage to specific protected objects caused by earthquakes; intensity rapid reporting can only provide regional and minute-level intensity information after the earthquake, which is not timely, and the early warning accuracy for specific protected objects is not high. At the same time, it is necessary to establish dense monitoring stations on a large scale, and the construction cost is high.

[0004] The existing railway earthquake early warning system generally adopts a center-based model, which cannot meet the time efficiency requirements of earthquake early warning for railway projects under construction in seconds. For example, my country's intensity rapid report can only provide intensity rapid report information 2-5 minutes after the earthquake. In order to improve the accuracy of the alarm, earthquake early warning systems for railway operations at home and abroad need to densely deploy stations along the line. At the same time, in order to identify interference sources as much as possible, the acquisition equipment needs to use a high-cost three-axis force balance accelerometer. In addition, the transmission of seismic data generally adopts wired transmission, and for important construction sites such as railway engineering bridges and long tunnels under construction, the construction period is mostly in unmanned areas in the wild, and the supporting facilities are incomplete. The system cannot meet the requirements of field power supply and information transmission. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method and system for early warning of earthquake intensity at key construction sites during railway construction, which can realize early warning of earthquake intensity at key construction sites of railway projects under construction in seconds, increase timeliness, and improve early warning accuracy. The specific scheme is as follows:

[0006] A method for early warning of earthquake intensity at key construction sites during railway construction, comprising:

[0007] Obtain waveform analysis results corresponding to on-site seismic data;

[0008] According to the waveform analysis results, identifying earthquake P wave events at frontier stations;

[0009] If the earthquake P wave event at the frontier station triggers an alarm for a single station, the earthquake magnitude of the single station is obtained and the epicenter distance is calculated, and the intensity of the working point is calculated according to the earthquake magnitude of the single station and the epicenter distance;

[0010] If the P-wave event of the frontier station earthquake triggers an alarm for more than two stations, the magnitude of the earthquake at the two stations is obtained and the earthquake positioning of the two stations is performed, and the intensity of the working point is calculated according to the magnitude of the earthquake at the two stations and the earthquake positioning results of the two stations;

[0011] When the calculated intensity value of the work site exceeds IV degree, an intensity warning is issued to the work site.

[0012] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, a first formula is used to identify earthquake P wave events at frontier stations; the first formula is:

[0013]

[0014] Where i is the current sampling point, x(i) is the current three-dimensional synthetic acceleration record, α is the sampling interval of the seismic signal, Δt is the time window length, and L Small (Δt) is the smaller value of the upper and lower waveform lengths of the seismic waveform axis, L big (Δt) is the length of the upper and lower waveforms on the seismic waveform axis and the relatively larger value of the two, X(i) is the amplitude corresponding to the current time sampling point, and T is the current time sampling point.

[0015] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, the step of obtaining the earthquake magnitude at a single station includes:

[0016] The logarithm of the product of the maximum displacement and the maximum velocity of the waveform after the single station is triggered for a set time and the logarithm of the maximum value of the Fourier transform within the set time window are used as sensitivity factors;

[0017] Using the least square method to fit the relationship between the sensitivity factor and the earthquake magnitude;

[0018] The earthquake magnitude at a single station is obtained according to the fitted relationship.

[0019] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, the relationship between the sensitivity factor and the earthquake magnitude is:

[0020] M=a*log|P max *v max |+b*K max +c

[0021] Where M is the magnitude of the earthquake, P max is the maximum amplitude within the set time window, v max K is the maximum speed within the set time window. max is the maximum value of the Fourier transform spectrum within the set time window, and a, b, and c are three constants calculated by the least squares method.

[0022] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, the calculating of the epicenter distance includes:

[0023] The epicenter distance is calculated based on the dominant period and the maximum acceleration within the set time window.

[0024] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, after calculating the epicenter distance, it also includes:

[0025] The azimuth of a single station is determined by the three-dimensional covariance matrix;

[0026] The epicenter position of a single station is located according to the determined azimuth and the calculated epicenter distance.

[0027] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, the performing of dual-station earthquake positioning includes:

[0028] By searching in the pre-established arrival time difference matrix, the position whose arrival time difference is closest to the P-wave triggering time difference of the two frontier stations is searched, and this position is the epicenter position of the two frontier stations;

[0029] According to the epicenter positions of the two frontier stations, the distance between the epicenter and the key working point is obtained as the dual-station earthquake positioning result.

[0030] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, the step of calculating the intensity of the working point according to the earthquake magnitude of the single station and the epicenter distance includes:

[0031] Calculating the PGA of a key working point according to the earthquake magnitude of the single station and the epicenter distance; calculating the intensity of the working point according to the calculated PGA of the key working point;

[0032] The calculating of the intensity of the working point according to the earthquake magnitudes of the two stations and the earthquake positioning results of the two stations comprises:

[0033] The PGA of the key working point is calculated according to the magnitude of the earthquake at the dual stations and the distance between the epicenter and the key working point; and the intensity of the working point is calculated according to the calculated PGA of the key working point.

[0034] Preferably, in the earthquake intensity early warning method provided in the embodiment of the present invention, it also includes:

[0035] Determine whether the on-site station at the work site triggers an event within a preset time period after the two frontier stations are triggered;

[0036] If not, it is determined to be a false alarm event and a false alarm cancellation is issued to the work site;

[0037] If so, after the local station triggers the preset time period, if the PGA of the local station no longer increases, an alarm cancellation is sent to the work site.

[0038] The embodiment of the present invention also provides an earthquake intensity early warning system for key work points during railway construction, including: earthquake monitoring equipment, network transmission equipment, cloud server and power supply equipment;

[0039] The power supply equipment includes a solar panel, a battery and a controller, and is used to provide electrical energy;

[0040] The network transmission device is used to network the earthquake monitoring device and the cloud server via a wireless network;

[0041] The earthquake monitoring equipment is used to collect on-site earthquake data in real time;

[0042] The cloud server is used to create a virtual station according to the station information; the virtual station is used to receive the on-site seismic data, perform data waveform analysis on the cloud, and obtain waveform analysis results corresponding to the on-site seismic data;

[0043] The cloud server is also used to obtain the waveform analysis results; identify the earthquake P wave events at the frontier station according to the waveform analysis results; when the earthquake P wave event at the frontier station triggers an alarm for a single station, obtain the earthquake magnitude of the single station and calculate the epicenter distance, and calculate the intensity of the work point according to the earthquake magnitude of the single station and the epicenter distance; when the earthquake P wave event at the frontier station triggers an alarm for more than two stations, obtain the earthquake magnitude of two stations and perform dual-station earthquake positioning, and calculate the intensity of the work point according to the earthquake magnitude of the two stations and the dual-station earthquake positioning results.

[0044] It can be seen from the above technical scheme that the earthquake intensity early warning method for key work points during railway construction provided by the present invention includes: obtaining waveform analysis results corresponding to on-site seismic motion data; identifying earthquake P wave events at frontier stations based on the waveform analysis results; if the earthquake P wave event at the frontier station triggers an alarm for a single station, then obtaining the earthquake magnitude of the single station and calculating the epicenter distance, and calculating the intensity of the work point based on the earthquake magnitude and epicenter distance of the single station; if the earthquake P wave event at the frontier station triggers an alarm for more than two stations, then obtaining the earthquake magnitude of two stations and performing dual-station earthquake positioning, and calculating the intensity of the work point based on the earthquake magnitude of the two stations and the dual-station earthquake positioning results; when the calculated work point intensity value exceeds IV degrees, issuing an intensity warning to the work point.

[0045] Through the earthquake intensity early warning method provided by the present invention, a second-level earthquake intensity early warning can be achieved for key construction sites of railway projects under construction, and earthquake intensity early warning information can be provided to the construction sites before destructive earthquake waves arrive, thereby increasing timeliness and accuracy of early warning, eliminating the need for human intervention, and reducing personnel and property losses at the construction site. In addition, the present invention also provides a corresponding system for the earthquake intensity early warning method, further making the above method more practical, and the system has corresponding advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0047] Figure 1 A flowchart of an earthquake intensity early warning method provided by an embodiment of the present invention;

[0048] Figure 2 A schematic diagram of the layout principle of the on-site station and the frontier station provided in an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of a seismic waveform provided by an embodiment of the present invention;

[0050] Figure 4 A schematic diagram of a record 3 seconds before a magnitude 3.7 earthquake in a certain city provided by an embodiment of the present invention;

[0051] Figure 5 for Figure 4 Schematic diagram of the Fourier spectrum recorded from the beginning to the first 3 seconds;

[0052] Figure 6 A schematic diagram of the structure of an earthquake intensity early warning system provided by an embodiment of the present invention;

[0053] Figure 7 A specific flow chart of early warning collection for a single station provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] The present invention provides an earthquake intensity early warning method for key work points during railway construction, such as Figure 1 As shown, the following steps are included:

[0056] S101, obtaining waveform analysis results corresponding to on-site earthquake data;

[0057] It should be noted that the present invention can collect on-site seismic data in real time through on-site monitoring equipment; then the cloud server can create a virtual station based on the station information; the virtual station can receive the on-site seismic data, perform data waveform analysis in the cloud, and obtain waveform analysis results corresponding to the on-site seismic data; the cloud server can summarize the waveform analysis results, and perform subsequent operation steps to comprehensively judge and correct the intensity information of the construction point, and issue comprehensive earthquake warning information.

[0058] S102, identifying earthquake P wave events at frontier stations according to waveform analysis results;

[0059] It should be noted that the early warning target of key construction sites during railway construction is mainly to ensure the personal safety of construction workers and personnel. From this perspective, the early warning system of key construction sites during railway construction should have the function of on-site early warning. From the perspective of responding to large earthquakes in other places and improving the time of early warning, the early warning system of key construction sites during railway construction should also have the function of off-site early warning. Therefore, the layout of early warning monitoring stations at key construction sites during railway construction should follow the principle of "on-site + regional" monitoring, such as Figure 2 As shown, local stations are deployed in the center, and frontier stations are discretely distributed at preset intervals in areas set outward to the south, north, east and west of the center, while meeting certain economic requirements.

[0060] When an earthquake occurs, the source will stimulate seismic P waves and seismic S waves. When the seismic waves propagate to the frontier stations, they will cause obvious mutations in the seismic records, such as Figure 3 As shown, there are obvious differences in the records before and after the arrival of the seismic waves. The occurrence of an earthquake can be identified by judging the difference in waveforms.

[0061] S103, if the earthquake P wave event at the frontier station triggers an alarm for a single station, the earthquake magnitude of the single station is obtained and the epicenter distance is calculated, and the intensity of the working point is calculated according to the earthquake magnitude and epicenter distance of the single station;

[0062] It should be emphasized that the alarm triggered by a frontier station and a local station at the work site is also considered as the above-mentioned single station triggering alarm. If the local station is triggered first, there are two situations. The first situation is a false trigger, and the second situation is that the epicenter is closer to the local station than other frontier stations. At this time, it is in the early warning blind area. When this happens, the early warning is not timely, and the process returns to step S102 to continue monitoring.

[0063] S104. If the earthquake P wave event at the frontier station triggers an alarm for more than two stations, the earthquake magnitude of the two stations is obtained and the earthquake positioning of the two stations is performed, and the intensity of the working point is calculated according to the earthquake magnitude of the two stations and the earthquake positioning results of the two stations;

[0064] It can be understood that when an earthquake P-wave event at a frontier station triggers an alarm for more than two stations, the second frontier station triggers an alarm subsequently after the first frontier station triggers an alarm; here, it is necessary to obtain the magnitude of the second frontier station, that is, the step of obtaining the earthquake magnitude in step S103 is the same as the step of obtaining the earthquake magnitude in step S104, except that step S104 needs to obtain the earthquake magnitudes of two stations.

[0065] S105. When the calculated intensity value of the work site exceeds IV degree, an intensity warning is issued to the work site.

[0066] In practical applications, the earthquake intensity early warning method provided by the present invention can be applied to key construction sites during railway construction; the key construction sites can be important construction sites such as railway bridges under construction and long tunnels.

[0067] In the above-mentioned earthquake intensity warning method provided in the embodiment of the present invention, a second-level earthquake intensity warning can be achieved for key work points of the railway project under construction. Before the destructive seismic waves arrive, earthquake intensity warning information can be provided to the work points, which increases timeliness and improves the accuracy of the warning. It does not require human intervention and reduces personnel and property losses at the construction site.

[0068] In specific implementation, in the earthquake intensity early warning method provided in the embodiment of the present invention, the following formula is used to identify the earthquake P wave event at the frontier station in step S102:

[0069]

[0070] Where i is the current sampling point, x(i) is the current three-dimensional synthetic acceleration record, α is the sampling interval of the seismic signal, Δt is the time window length, and L Small(Δt) is the smaller value of the upper and lower waveform lengths of the seismic waveform axis, L big (Δt) is the length of the upper and lower waveforms on the seismic waveform axis and the relatively larger value of the two, X(i) is the amplitude corresponding to the current time sampling point, and T is the current time sampling point.

[0071] In practical applications, by setting the threshold Y, when X>Y, the single station trigger condition is met. Due to different geological conditions, earthquakes have obvious regional characteristics. For different regions, Y and Δt can be determined based on the actual waveform, and Δt is generally 2-3 seconds.

[0072] The first term of the above formula (1) compares the sum of the squares of the amplitudes in the Δt time window before and after the current time point. Since the amplitude increases significantly when the seismic wave arrives, this term can reflect the difference in amplitude changes before and after the seismic wave. The second term of the above formula (1) compares the sum of the waveform lengths in the time window before and after the current point. Since the amplitude becomes significantly stronger after the seismic wave arrives, this formula can enhance the ability to pick up weak seismic phase earthquakes. The third term of the above formula (1) compares the waveform lengths above and below the axis in the Δt time window after the current sampling point. Since for a real seismic event, the seismic waveform is basically symmetrical above and below the axis, the waveform length ratio will be close to 1. If the event is a non-seismic interference event, such as electromagnetic interference, screening, tamping and other construction interference, it does not meet the symmetry condition, and the waveform length ratio will be close to 0. The third term can retain the intensity of the real earthquake, reduce the intensity of the interference event, and avoid false triggering of non-seismic events. In other words, the above formula (1) can ensure the accurate pickup of seismic P waves in the case of weak seismic phases, and at the same time has the characteristics of preventing false triggering.

[0073] In specific implementation, in the earthquake intensity early warning method provided in the embodiment of the present invention, step S103 obtains the earthquake magnitude of a single station, which may specifically include: taking the logarithm of the product of the maximum displacement and the maximum velocity of the waveform after the single station is triggered for a set time (such as 3s) and the logarithm of the maximum value of the Fourier transform in the time window of the set time (such as 3s) as sensitive factors; fitting the relationship between the sensitive factor and the earthquake magnitude using the least squares method; and obtaining the earthquake magnitude of the single station according to the fitted relationship. The set time can be set to 3s or other seconds, which is not limited here.

[0074] It should be noted that the magnitude of an earthquake reflects the intensity of the earthquake. As the magnitude of an earthquake increases from small to large, the amplitude of the underground medium caused by the large magnitude will inevitably increase. Similarly, the vibration speed of the medium will also gradually increase. In addition, the magnitude of an earthquake is also intrinsically related to the frequency. Therefore, the present technical solution can adopt the maximum waveform displacement P after the event triggering setting time (such as 3s) in step S102. max With maximum speed v maxThe logarithm of the product of and the logarithm of the maximum value of Fourier transform within a set time window (such as 3s) are used as sensitivity factors. Based on a large amount of historical data, the least squares method is used to fit the calculation formula of sensitivity factors and earthquake magnitude:

[0075] M=a*log|P max *v max |+b*K max +c (2)

[0076] Where M is the magnitude of the earthquake, P max is the maximum amplitude within the set time window (such as 3s), v max K is the maximum speed within the set time window (such as 3s), max is the maximum value of the Fourier transform spectrum within the set time window, a, b, c are three constants calculated by the least squares method. Figure 4 The following is a schematic diagram showing the 3s record before a 3.7 magnitude earthquake in a certain city. Figure 5 The Fourier spectrum recorded in the first 3 seconds of the first arrival is shown. Figure 5 The maximum value of the Fourier transform spectrum can be found in .

[0077] In practical applications, due to the large regional differences in earthquakes, a, b, and c need to be calculated using local historical earthquake records. The more historical earthquakes there are, the more accurate the fitting formula is. The present invention applies the magnitude sensitivity factors in the time domain and frequency domain to the magnitude calculation formula (2), and fits the empirical formula with multiple parameters to obtain better calculation accuracy.

[0078] Furthermore, in a specific implementation, in the earthquake intensity warning method provided in the embodiment of the present invention, step S103 of calculating the epicenter distance may specifically include: calculating the epicenter distance according to the dominant period and the maximum acceleration within a set time window.

[0079] Specifically, in the present invention, the epicenter distance of a single station is calculated using the dominant period τ within a set time window (such as 3s) after triggering. pmax With the maximum acceleration P max The specific calculation formula is as follows:

[0080]

[0081] Among them, α0, β, and γ are three constants. The values ​​of these three constants can be obtained by using the least squares method. R represents the epicenter distance, P max It represents the maximum value of the acceleration amplitude of the P wave within the set time window (such as 3s). When an earthquake event occurs, the observed τ pmax and P max , according to the above relationship, the epicenter distance R of each station is calculated. τ pmaxThe calculation of is as follows:

[0082]

[0083]

[0084]

[0085] Among them, x i It is the vertical velocity record, which can be obtained by integrating the acceleration data. Before integration, it must be band-pass filtered. α' is a smoothing parameter, which is generally given as 0.99. Before the magnitude estimation, the vertical acceleration record is first band-pass filtered at 0.075Hz to 5Hz. τ pmax τ is the time window within the set time (such as 3s) p The maximum value of .

[0086] In a specific implementation, in the above-mentioned earthquake intensity warning method provided in an embodiment of the present invention, after executing step S103 to calculate the epicentral distance, it can also include: determining the azimuth of a single station through a three-dimensional covariance matrix; locating the epicenter position of the single station according to the determined azimuth and the calculated epicentral distance.

[0087] Specifically, in the present invention, the azimuth angle of a single station is calculated by using the three-dimensional covariance matrix:

[0088]

[0089] Among them, the original three-dimensional acceleration record Var(X) = COV(X,X), ns represents the north-south direction, ew represents the east-west direction, and ud represents the vertical direction (vertical). The covariance operator is defined as in are the average values ​​of A and B respectively. The three-dimensional (non-zero) vector that satisfies the equation MX = λX represents the three main axis directions of the ellipsoid. This three-dimensional vector is the eigenvector of the matrix M. Assuming that the three eigenroots obtained from the matrix M are λ1>λ2>λ3, their corresponding eigenvectors are expressed as Then by The constructed matrix is ​​the required characteristic matrix X.

[0090] The azimuth of the earthquake is determined by the projection of the eigenvector corresponding to the maximum eigenvalue on the horizontal plane. Suppose the eigenvector corresponding to the maximum eigenvalue is The azimuth of the actual earthquake relative to the station needs to be combined with The sign of ud and the size relationship of ns and ew are determined. The specific steps are as follows:

[0091] definition When ud<0, the azimuth angle in radians can be calculated according to the following formula:

[0092]

[0093] When ud>0, the azimuth is calculated as follows:

[0094]

[0095] The final calculated azimuth is It means the clockwise angle of the earthquake relative to the geographic North Pole where the station is located. The epicenter position can be located by the azimuth and the epicenter distance calculated in step S103.

[0096] In specific implementation, in the above-mentioned earthquake intensity warning method provided in an embodiment of the present invention, step S103 calculates the intensity of the work point according to the earthquake magnitude and epicenter distance of a single station, which can specifically include: calculating the PGA (three-dimensional composite peak acceleration) of the key work point according to the earthquake magnitude and epicenter distance of a single station; calculating the intensity of the work point according to the calculated PGA of the key work point.

[0097] Specifically, the magnitude M and epicenter distance R obtained in step S103 are used to calculate the PGA of the work point using the attenuation formula of PGA. The calculation formula is as follows:

[0098] ln(PGA)=C1+C2M+C3lnR (10)

[0099] Among them, C1, C2, and C3 are unknown coefficients, which are calculated by the least squares method based on local historical earthquake data.

[0100] Then the PGA is obtained by calculation, and the PGA is converted into intensity through the empirical formula. The specific formula is as follows:

[0101] I A =3.17log 10 (PGA)+6.59 (11)

[0102] When I A >IV, an intensity warning will be issued to the work site.

[0103] Furthermore, in a specific implementation, in the above-mentioned earthquake intensity warning method provided in an embodiment of the present invention, step S104 performs dual-station earthquake positioning, which may specifically include: by querying in a pre-established arrival time difference matrix, searching for the position in the matrix where the inverse time difference is closest to the P-wave triggering time difference of the two frontier stations, and this position is the epicenter position of the two frontier stations; according to the epicenter position of the two frontier stations, obtaining the distance between the epicenter of the two frontier stations and the key working point (i.e., the epicenter distance) as the dual-station earthquake positioning result.

[0104] Specifically, when two stations trigger an alarm, the P wave triggering time difference ΔT of the two stations is 1，2 It is known that by searching in the previously established arrival time difference matrix, the inversion time difference ΔT and ΔT in the search matrix 1，2 The closest position is the epicenter. The method to establish the time difference matrix is ​​as follows:

[0105] Assume that the propagation speed of earthquake P wave is about V p , the focal depth is H, and the time it takes for the seismic wave to propagate to two different ground stations a and b is t a and t b :

[0106]

[0107]

[0108] The time difference between the two stations is:

[0109] ΔT a，b =t a -t b (D a >D b ) (14)

[0110] The propagation speed of earthquake P waves is about 5.5km / s-7km / s. Assuming the average propagation speed of P waves is V p The frequency is 6.25km / s, the focal depth is H=0km, and with the key working point as the center, the areas 200km to the south, north, east and west are discretized at intervals of 1km. Since the positions of the two stations are known, it is assumed that each discrete point is the earthquake source, and the inverse time difference from the discrete point to the two stations is calculated and coexists in the corresponding position of the inverse time difference matrix, that is, a 400*400 arrival time difference matrix can be obtained.

[0111] When an earthquake occurs, if stations 1 and 2 are triggered first, it is only necessary to search for the time difference matrix and the time difference ΔT between the real stations. 1，2 The closest point is the epicenter, and the distance between the epicenter and the key work point can be obtained.

[0112] It should be noted that the above method uses the method of establishing a time difference matrix for dual-station positioning. This method completes the calculation of the time difference from each discrete point to each station in advance. When an earthquake occurs, only the minimum difference needs to be searched to determine the epicenter, which is highly timely. In addition, the above method uses two stations for positioning, which is more accurate than single-station positioning, and can also avoid alarms caused by false triggering.

[0113] In the specific implementation, in the earthquake intensity early warning method provided by the embodiment of the present invention, step S104 calculates the intensity of the work point according to the earthquake magnitude of the dual stations and the earthquake positioning results of the dual stations, which may specifically include: calculating the PGA of the key work point according to the earthquake magnitude of the dual stations and the distance between the epicenter and the key work point; calculating the intensity of the work point according to the calculated PGA of the key work point. Specifically, the PGA of the key work point can be calculated using formula (10), and the intensity of the work point can be calculated using formula (11).

[0114] It should be noted that, in view of the existing P-wave early warning technology, the frontier station of the present invention measures PGA to calculate the intensity of the work site, and at the same time, the intensity prediction information is corrected through the P-wave early warning information of the on-site station of the work site, thereby further improving the accuracy of the early warning information. At the same time, by utilizing the different triggering sequences of the frontier station and the central station, it is possible to effectively eliminate interference false alarms caused by the construction environment, and realize the organic combination of on-site early warning and regional early warning.

[0115] Furthermore, in the specific implementation, the earthquake intensity early warning method provided in the embodiment of the present invention may also include: judging whether the on-site station at the construction site triggers an event within a preset time period after the two frontier stations are triggered; if not, it is determined to be a false alarm event, and a false alarm cancellation is issued to the construction site; if so, after the on-site station triggers the preset time period, if the PGA of the on-site station no longer increases, an alarm cancellation is issued to the construction site. In this way, in view of the characteristics of large interference in the construction environment of railway projects, false alarms caused by non-earthquake events can be avoided by formulating earthquake early warning and alarm mechanism processes.

[0116] Specifically, the preset time period can be set to 2 minutes, or other time periods, which are not limited here. If the on-site station at the work site does not trigger an event within 2 minutes after the two frontier stations are triggered, it is determined to be a false alarm event, and a false alarm cancellation is issued to the work site. If the on-site station at the work site triggers an event within 2 minutes after the two frontier stations are triggered, and the PGA of the on-site station does not increase 2 minutes after the center is triggered, an alarm cancellation is issued to the work site.

[0117] Based on the same inventive concept, an embodiment of the present invention also provides an earthquake intensity warning system. Since the principle of solving the problem by the system is similar to that of the aforementioned earthquake intensity warning method, the implementation of the system can refer to the implementation of the earthquake intensity warning method, and the repeated parts will not be repeated.

[0118] In specific implementation, the earthquake intensity early warning system provided by the embodiment of the present invention is used at key work points during railway construction, and specifically includes: earthquake monitoring equipment, network transmission equipment, cloud servers and power supply equipment;

[0119] Power supply equipment, including solar panels, batteries and controllers, is used to provide electrical energy; such as Figure 6As shown, the present invention uses solar power supply equipment, mainly using solar energy for power supply;

[0120] Network transmission equipment, used to network earthquake monitoring equipment and cloud servers through wireless networks; network transmission equipment can transmit earthquake data packets to designated servers through 4G networks;

[0121] Earthquake monitoring equipment is used to collect on-site earthquake data in real time; such as Figure 6 As shown, the earthquake monitoring equipment may be composed of an earthquake monitoring instrument (intensity meter), which has the function of collecting on-site earthquake data in real time and the function of sending data packets through a wireless network;

[0122] The cloud server is used to create a virtual station based on the station information; the virtual station is used to receive on-site seismic data, perform data waveform analysis on the cloud, and obtain waveform analysis results corresponding to the on-site seismic data;

[0123] The cloud server is also used to obtain waveform analysis results; identify earthquake P-wave events at the frontier station based on the waveform analysis results; when an earthquake P-wave event at the frontier station triggers an alarm for a single station, obtain the earthquake magnitude at the single station and calculate the epicenter distance, and calculate the intensity of the working point based on the earthquake magnitude and epicenter distance of the single station; when an earthquake P-wave event at the frontier station triggers an alarm for more than two stations, obtain the earthquake magnitude at two stations and perform dual-station earthquake positioning, and calculate the intensity of the working point based on the earthquake magnitude at the two stations and the dual-station earthquake positioning results.

[0124] It should be noted that the cloud server uses load balancing and virtualization technology. Each server is responsible for data processing of multiple monitoring stations around key work points, which can ensure the timeliness of real-time data processing.

[0125] Specifically, the earthquake intensity warning process may include: networking the on-site earthquake monitoring equipment with the server through a wireless router, the on-site earthquake monitoring equipment pushes the collected real-time data to the server, the server creates a virtual station through the station information, and runs the virtual station in the cloud to calculate and analyze the real-time waveform, while integrating the real-time waveform analysis results of other virtual stations to issue comprehensive earthquake warning information. Figure 7 The specific flow chart of early warning collection at a single station is shown.

[0126] When multiple virtual stations trigger alarms, the server will use the information sent by multiple stations to comprehensively judge and correct the intensity information of the construction point. The specific operation process can refer to the implementation of the above-mentioned earthquake intensity early warning method provided by the present invention.

[0127] In the above-mentioned earthquake intensity warning system provided in the embodiment of the present invention, the architecture is simple, and the system warning function can be realized by using relatively low-cost monitoring equipment. Compared with the existing earthquake warning system in the operational period, the cost is greatly reduced, and it is also easier to implement and maintain. Through this system, a second-level earthquake intensity warning can be achieved for key work points of the railway project under construction. Before the destructive seismic waves arrive, earthquake intensity warning information can be provided to the work points, which increases timeliness and improves the accuracy of the warning. No human intervention is required, and the loss of personnel and property at the construction site is reduced.

[0128] For more specific working processes of the above-mentioned components, please refer to the corresponding contents disclosed in the aforementioned embodiments, which will not be repeated here.

[0129] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the systems, devices, and storage media disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0130] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0131] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0132] In summary, an earthquake intensity warning method for key construction sites during railway construction provided by an embodiment of the present invention includes: obtaining waveform analysis results corresponding to on-site seismic data; identifying earthquake P wave events at frontier stations according to the waveform analysis results; if the earthquake P wave event at the frontier station triggers an alarm for a single station, the earthquake magnitude of the single station is obtained and the epicenter distance is calculated, and the intensity of the construction site is calculated according to the earthquake magnitude and epicenter distance of the single station; if the earthquake P wave event at the frontier station triggers an alarm for more than two stations, the earthquake magnitude of the double stations is obtained and the double-station earthquake positioning is performed, and the intensity of the construction site is calculated according to the earthquake magnitude of the double stations and the double-station earthquake positioning results; when the calculated construction site intensity value exceeds IV degrees, an intensity warning is issued to the construction site. In this way, a second-level earthquake intensity warning for key construction sites of railway projects under construction can be achieved, and earthquake intensity warning information can be provided to the construction site before the destructive seismic wave arrives, which increases timeliness and improves the accuracy of the warning, does not require human intervention, and reduces the loss of personnel and property at the construction site. In addition, the present invention also provides a corresponding system for the earthquake intensity early warning method, which further makes the above method more practical, and the system has corresponding advantages.

[0133] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0134] The earthquake intensity early warning method and system for critical work points during railway construction provided by the present invention are introduced in detail above. Specific examples are used herein to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for early warning of earthquake intensity at key construction sites during railway construction, characterized in that: include: Obtain waveform analysis results corresponding to on-site seismic data; According to the waveform analysis results, a first formula is used to identify earthquake P wave events at frontier stations; the first formula is: Where i is the current sampling point, x(i) is the current three-dimensional synthetic acceleration record, α is the sampling interval of the seismic signal, Δt is the time window length, and L Small (Δt) is the length of the upper and lower waveforms of the earthquake waveform axis and the relatively smaller value of the two. big (Δt) is the length of the upper and lower waveforms on the seismic waveform axis and the relatively larger value of the two, X(i) is the amplitude corresponding to the current time sampling point, and T is the current time sampling point; If the earthquake P wave event at the frontier station is a single station trigger alarm, the logarithm of the product of the maximum displacement and the maximum velocity of the waveform after the single station is triggered for a set time and the logarithm of the maximum value of the Fourier transform within the set time window are used as sensitivity factors; the relationship between the sensitivity factor and the earthquake magnitude is fitted using the least squares method; the single station earthquake magnitude is obtained according to the fitted relationship and the epicenter distance is calculated, and the working point intensity is calculated according to the single station earthquake magnitude and the epicenter distance; If the P-wave event of the frontier station earthquake triggers an alarm for more than two stations, the magnitude of the earthquake at the two stations is obtained and the earthquake positioning of the two stations is performed, and the intensity of the working point is calculated according to the magnitude of the earthquake at the two stations and the earthquake positioning results of the two stations; When the calculated intensity value of the work site exceeds IV degree, an intensity warning is issued to the work site.

2. The earthquake intensity early warning method according to claim 1, characterized in that: The relationship between the sensitivity factor and the earthquake magnitude is: M=a*logP max *v max / +b*K max +c Where M is the magnitude of the earthquake, P max is the maximum amplitude within the set time window, v max K is the maximum speed within the set time window. max is the maximum value of the Fourier transform spectrum within the set time window, and a, b, and c are three constants calculated by the least squares method.

3. The earthquake intensity early warning method according to claim 2, characterized in that: The calculation of epicenter distance comprises: The epicenter distance is calculated based on the dominant period and the maximum acceleration within the set time window.

4. The earthquake intensity early warning method according to claim 3, characterized in that: After calculating the epicentral distance, the method further includes: The azimuth of a single station is determined by the three-dimensional covariance matrix; The epicenter position of a single station is located according to the determined azimuth and the calculated epicenter distance.

5. The earthquake intensity early warning method according to claim 4, characterized in that: The dual-station earthquake positioning comprises: By searching in the pre-established arrival time difference matrix, the position whose arrival time difference is closest to the P-wave triggering time difference of the two frontier stations is searched, and this position is the epicenter position of the two frontier stations; According to the epicenter positions of the two frontier stations, the distance between the epicenter and the key working point is obtained as the dual-station earthquake positioning result.

6. The earthquake intensity early warning method according to claim 5, characterized in that: The calculating of the intensity of the working point according to the earthquake magnitude of the single station and the epicenter distance comprises: Calculating the PGA of a key working point according to the earthquake magnitude of the single station and the epicenter distance; calculating the intensity of the working point according to the calculated PGA of the key working point; The calculating of the intensity of the working point according to the earthquake magnitudes of the two stations and the earthquake positioning results of the two stations comprises: The PGA of the key working point is calculated according to the magnitude of the earthquake at the dual stations and the distance between the epicenter and the key working point; and the intensity of the working point is calculated according to the calculated PGA of the key working point.

7. The earthquake intensity early warning method according to claim 6, characterized in that: Also includes: Determine whether the on-site station at the work site triggers an event within a preset time period after the two frontier stations are triggered; If not, it is determined to be a false alarm event and a false alarm cancellation is issued to the work site; If so, after the local station triggers the preset time period, if the PGA of the local station no longer increases, an alarm cancellation is sent to the work site.

8. An earthquake intensity early warning system for key construction sites during railway construction, characterized in that: include: Earthquake monitoring equipment, network transmission equipment, cloud servers and power supply equipment; The power supply equipment includes a solar panel, a battery and a controller, and is used to provide electrical energy; The network transmission device is used to network the earthquake monitoring device and the cloud server via a wireless network; The earthquake monitoring equipment is used to collect on-site earthquake data in real time; The cloud server is used to create a virtual station according to the station information; the virtual station is used to receive the on-site seismic data, perform data waveform analysis on the cloud, and obtain waveform analysis results corresponding to the on-site seismic data; The cloud server is further used to obtain the waveform analysis result; according to the waveform analysis result, a first formula is used to identify the earthquake P wave event of the frontier station; the first formula is: Where i is the current sampling point, x(i) is the current three-dimensional synthetic acceleration record, α is the sampling interval of the seismic signal, Δt is the time window length, and L Small (Δt) is the length of the upper and lower waveforms of the earthquake waveform axis and the relatively smaller value of the two. big (Δt) is the length of the upper and lower waveforms on the earthquake waveform axis and the relatively larger value of the two, X(i) is the amplitude corresponding to the current time sampling point, and T is the current time sampling point; when the earthquake P wave event at the frontier station triggers an alarm for a single station, the logarithm of the product of the maximum displacement and the maximum velocity of the waveform after the single station is triggered for a set time and the logarithm of the maximum value of the Fourier transform within the set time window are used as sensitive factors; the relationship between the sensitive factor and the earthquake magnitude is fitted using the least squares method; the earthquake magnitude of the single station is obtained according to the fitted relationship and the epicenter distance is calculated, and the intensity of the working point is calculated according to the earthquake magnitude of the single station and the epicenter distance; when the earthquake P wave event at the frontier station triggers an alarm for more than two stations, the earthquake magnitude of the dual stations is obtained and the dual-station earthquake positioning is performed, and the intensity of the working point is calculated according to the earthquake magnitude of the dual stations and the dual-station earthquake positioning results.

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