Method and program product for monitoring and safety warning of collapse of a building composite bridge

Abstract

The present application relates to the technical field of civil engineering construction safety monitoring, in particular to a kind of collapse monitoring safety early warning method and program product of comprehensive bridge under construction, comprising: generating dynamic safety threshold envelope adapted to current working condition;Calculate the residual of its measured value and the dynamic safety threshold envelope;When residual is over limit, extract the energy dissipation characteristics of measured data;If it is judged to be unstable, generate blocking instruction before bridge structure occurs physical fall and causes pipeline to reach tensile limit;The blocking instruction is used to trigger the action of the circuit breaking mechanism preinstalled at the two ends of the municipal pipe gallery, cut off the transmission line inside the pipe gallery, and synchronously trigger the traffic lock signal and emergency data broadcast;The present application overcomes the defect that traditional fixed threshold cannot adapt to the dramatic change of bridge stiffness under construction by establishing a time-varying mechanical model of structure, so as to ensure high sensitivity to the loss of structural stiffness while effectively shielding false alarms caused by normal construction vibration such as concrete pouring and hanging basket walking.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of civil engineering construction safety monitoring, in particular to a safety early warning method and program product for collapse monitoring of a comprehensive bridge under construction. BACKGROUND

[0002] With the acceleration of urbanization, modern large-scale bridge projects are often not only traffic chokepoints, but also important carriers of municipal pipe corridors for power, communication, gas, water supply, etc. In the existing bridge construction safety monitoring technology, total station, GNSS (Global Navigation Satellite System), inclinometer and stress-strain sensor are usually used to monitor the geometric shape and stress state of the bridge structure. However, in actual engineering application, the existing monitoring and early warning system mainly has the following problems:

[0003] Firstly, in the setting of monitoring threshold, the existing technology mainly uses fixed threshold based on design specifications or empirical values. However, during the construction life cycle of the bridge under construction, the structural stiffness, boundary conditions and load distribution dynamically change with the advancement of construction processes (such as concrete pouring, hanging basket walking, prestress tensioning, etc.). The use of a single or static threshold system often cannot adapt to the dramatic evolution of structural physical parameters, leading to false alarms under normal construction disturbances, and possible missed alarms in the early stage of real structural instability due to the wide threshold.

[0004] Secondly, for bridges carrying municipal pipelines, whether in the process of new construction or reconstruction, the normal operation of existing pipelines or temporary pipelines needs to be ensured. The current structure monitoring system and pipeline control system are usually operated in a "island" mode independently of each other. The blocking mechanism of the pipeline system often relies on the sudden pressure drop or flow anomaly signal after the pipeline itself breaks. This means that only when the bridge has collapsed substantially and caused the pipeline to physically break, the cut-off command will be triggered. This delayed response mechanism cannot complete the medium cutoff within the "time window" before the pipeline reaches its limit, and is prone to secondary disasters (such as gas leakage explosion, high-voltage cable short circuit fire, etc.). SUMMARY

[0005] The present application provides a safety early warning method and program product for collapse monitoring of a comprehensive bridge under construction, which realizes accurate identification of construction interference and structural instability precursors, and realizes pre-emptive linkage blocking of pipelines before the structure is completely destroyed.

[0006] The present application is realized by the following technical solutions:

[0007] A safety early warning method for collapse monitoring of a comprehensive bridge under construction, comprising the following steps:

[0008] The dynamic reference construction step: obtaining the current construction process progress data of the bridge, establishing a time-varying mechanical model of the structure evolving with the process, and combining with the environmental thermal effect compensation to generate a dynamic safety threshold envelope line adapting to the current working condition;

[0009] The precursor feature recognition step: real-time acquisition of the motion state data of the key nodes of the bridge, calculation of the residual error between the measured value and the dynamic safety threshold envelope line; when the residual error is out of limit, the energy dissipation feature of the measured data is extracted;

[0010] The instability determination and blocking step: determining whether the structure is in an irreversible instability collapse stage according to the energy dissipation feature; if instability is determined, a blocking instruction is generated before the bridge structure falls physically and causes the pipeline to reach the tensile limit;

[0011] The emergency execution step: triggering the action of the circuit breaking mechanism pre-installed at both ends of the municipal pipe gallery by using the blocking instruction, cutting off the transmission line inside the pipe gallery, and synchronously triggering the traffic blocking signal and the emergency data broadcast.

[0012] Optionally, the method for establishing the time-varying mechanical model of the structure in the dynamic reference construction step specifically comprises:

[0013] Discretize the construction process progress data into a plurality of process nodes, and the process nodes correspond to different structural system conversion states;

[0014] According to the type of the process node at the current time, the stiffness matrix of the structure finite element model is updated in real time, and a real-time construction load vector is introduced to calculate the theoretical state reference value under the current working condition;

[0015] Acquire the cross-section temperature gradient data of the bridge structure, calculate the temperature additional deformation amount by using a preset thermal sensitivity coefficient, superimpose the temperature additional deformation amount to the theoretical state reference value, and obtain the corrected dynamic reference value.

[0016] Optionally, the method for generating the dynamic safety threshold envelope line in the dynamic reference construction step comprises:

[0017] Identify the work type of the current process node, and the work type at least includes a static curing stage and a dynamic work stage;

[0018] According to the work type, a corresponding process disturbance factor is selected, and the numerical value of the process disturbance factor in the dynamic work stage is greater than that in the static curing stage;

[0019] The dynamic safety bandwidth is calculated by multiplying the sensor inherent noise reference value by the process disturbance factor, the dynamic safety bandwidth is superimposed on the upper and lower boundaries of the dynamic reference value, and the dynamic safety threshold envelope line is generated.

[0020] Optionally, the energy divergence feature extracted in the precursor feature recognition step includes a macro kinetic energy divergence component and a micro damage divergence component.

[0021] The extraction method of the macro kinetic energy divergence component includes:

[0022] The inclination data of the key node is parsed from the motion state data, the angular velocity is obtained by differential calculation, and the phase plane trajectory based on the inclination and the angular velocity is constructed;

[0023] The dynamic instability index of the structure is calculated, and the dynamic instability index represents the nonlinear divergence degree of the kinetic energy of the structure relative to the potential energy barrier of gravity;

[0024] The dynamic instability index is taken as the macro kinetic energy divergence component;

[0025] The extraction method of the micro damage divergence component includes:

[0026] The high-frequency acceleration signal is parsed from the motion state data, and the high-frequency acoustic emission component representing the internal fracture of the material is separated by frequency domain decomposition;

[0027] The impact index of the high-frequency acoustic emission component is calculated by using a statistical fourth moment algorithm;

[0028] The impact index is taken as the micro damage divergence component.

[0029] Optionally, the method for extracting the energy divergence feature specifically includes:

[0030] When the phase plane trajectory breaks through the stable limit cycle and the dynamic instability index grows, it is determined that the macro kinetic energy divergence component is effective;

[0031] When the impact index exceeds a preset structure damage threshold, it is determined that the micro damage divergence component is effective;

[0032] Using a logical AND gate mechanism, when the macro kinetic energy divergence component and the micro damage divergence component are simultaneously determined to be effective, it is determined that the energy divergence feature is extracted, and it is determined that the structure enters an irreversible instability state.

[0033] Optionally, the method for determining instability in the instability determination and blocking step specifically includes:

[0034] A physical cut-off threshold corresponding to the voltage drop rate is set, and the physical cut-off threshold is greater than the voltage drop rate of the natural depletion of the battery;

[0035] While collecting the motion state data of the structure, the voltage drop rate of the system main power supply loop is monitored in real time;

[0036] When the energy dissipation feature is confirmed, or the voltage drop rate is monitored to exceed the physical cut-off threshold, the determination structure is in the unstable collapse stage, and the blocking program is activated immediately.

[0037] Optionally, the instability determination and the generation of the blocking instruction in the blocking step need to meet a time window constraint, specifically including:

[0038] According to the geometric structure and material elongation rate of the bridge pipe gallery, the theoretical safety time window required for the pipeline to free fall to the physical tensile limit height of the bridge is calculated;

[0039] The total time consumed by the system control to generate and send the blocking instruction, including the sum of the sampling filtering time, the algorithm calculation time and the breaker mechanical action time, is less than the theoretical safety time window.

[0040] Optionally, the emergency execution step specifically includes:

[0041] Emergency energy release mode switching: when receiving the blocking instruction or determining that the main power supply loop fails, the system cuts off the power supply of the conventional sensor, forces the pre-set transient high-power energy storage loop to be turned on, and uses the high-density energy released by the transient high-power energy storage loop to take over the power supply of the communication module;

[0042] Protocol degradation and compression: suspend the conventional full waveform data transmission protocol, and generate a minimalist SOS data packet containing only the device identity code, the collapse trigger time and the accident type code;

[0043] Saturated power broadcast: remove the conventional power consumption limit of the wireless transmission module, adjust the transmission power gain to the maximum saturation value allowed by the hardware, and broadcast the minimalist SOS data packet through the local wireless link and the remote communication link within the survival time window of the device free falling with the bridge.

[0044] Further, the emergency execution step further includes:

[0045] On-site physical blocking execution: using the hardware I / O interface of the edge gateway to directly drive the on-site sound and light alarm to start a high-decibel alarm, and synchronously light up the lane LED no-entry light, to achieve millisecond-level on-site traffic physical blocking before the remote management intervention.

[0046] A computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the built comprehensive bridge collapse monitoring safety warning method as described above.

[0047] Compared with the prior art, the present application has the following characteristics and beneficial effects:

[0048] The application overcomes the defect that the traditional fixed threshold cannot adapt to the dramatic change of the rigidity of the bridge under construction by establishing a structure time-varying mechanical model, thereby effectively shielding the false alarm caused by normal construction vibration such as concrete pouring and hanging basket walking while ensuring high sensitivity to the loss of structural rigidity.

[0049] The application can complete the physical cutting of the municipal pipe gallery transmission line in advance when the bridge structure falls physically, thereby eliminating the secondary disasters caused by passive pipeline pull-off.

[0050] The application solves the safety pain points such as "monitoring threshold misalignment" and "pipeline blocking lag" during the construction period of the comprehensive bridge under construction, and improves the risk control ability and emergency response speed of large infrastructure construction under extreme disasters. BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings illustrate exemplary embodiments of the present application and together with the description, explain the principles of the application, in which the drawings are included to provide further understanding of the present application, and form part of the description and are included as part of the specification, and do not constitute limitations on the embodiments of the present application.

[0052] Figure 1 is a flowchart of a comprehensive bridge under construction collapse monitoring safety warning method according to the application.

[0053] Figure 2 is a time-varying dynamic safety threshold envelope diagram according to the application.

[0054] Figure 3 is a instability determination diagram based on a phase plane trajectory according to the application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related content, and not to limit the present application.

[0056] In addition, it should be noted that only the parts related to the present application are shown in the drawings for ease of description.

[0057] In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0058] Embodiment one

[0059] As Figure 1As shown, the embodiment provides a method for monitoring and early warning of the collapse of a comprehensive bridge under construction. The overall operation process follows the technical path of "dynamic modeling-deviation identification-instability determination-linkage execution". The technical solution of the embodiment is described in detail as follows:

[0060] Dynamic reference construction step: obtain the current construction process progress data of the bridge (for example, is it currently in the concrete pouring stage or the prestressed tension stage), establish a structure time-varying mechanical model evolving with the process, and generate a dynamic safety threshold envelope line adapting to the current working condition in combination with environmental thermal effect compensation.

[0061] The structure time-varying mechanical model is a mathematical model that can update the physical parameters (such as stiffness and mass distribution) of the structure in real time as time passes and the working condition changes. On this basis, in combination with environmental thermal effect compensation (i.e. deducting normal deformation caused by thermal expansion and cold contraction), a dynamic safety threshold envelope line adapting to the current specific working condition is generated, such as Figure 2 As shown, the upper and lower limit values of the structure within the safe range in the current construction state are defined by the dynamic safety threshold envelope line. The horizontal axis in the figure represents the time process of the construction process, and the vertical axis represents the displacement or stress monitoring value of the key node.

[0062] As can be seen, in the T1 and T3 dynamic operation stages, due to the introduction of a larger process disturbance factor, the threshold bandwidth (envelope line distance) is significantly widened to tolerate construction noise; and in the T2 static curing stage, the threshold bandwidth is automatically contracted to improve the monitoring sensitivity to small structure creep or abnormal settlement.

[0063] The green line (theoretical state reference value) shows the theoretical displacement trajectory of the structure due to the stress system conversion as the T0 to T3 processes advance. For example, in T1 (pouring stage), the green line shows a large deflection trend (the value decreases from 0 to -20) due to the influence of wet heavy concrete load; and in T3 (tension stage), the green line shows an upward trend of the inverted arch (the value increases from -20 to +10) due to the influence of prestressed tension.

[0064] The yellow line (upper threshold) and the blue line (lower threshold) together constitute the dynamic safety threshold envelope line, and the vertical distance between the yellow line and the green line represents the dynamic safety bandwidth. As shown in the figure, in the T1 and T3 dynamic operation intervals, the yellow and blue lines expand outward, and the bandwidth significantly increases, which is because the system introduces a larger process disturbance factor to shield the background noise caused by construction machinery and prevent false alarms. On the contrary, in the T2 (static curing stage), the yellow and blue lines shrink towards the green line, and the bandwidth is extremely narrow, which is because the system switches to a smaller process disturbance factor, and the system enters a high sensitivity mode, which can capture small structure creep or abnormal settlement.

[0065] The precursor feature recognition step: real-time acquisition of the motion state data of the bridge key nodes, calculation of the residual of the measured value and the dynamic safety threshold envelope; when the residual is over-limit, the energy dissipation feature of the measured data is extracted.

[0066] After the establishment of the benchmark, the system enters the real-time monitoring state. Through the sensors installed on the bridge, the motion state data (such as displacement, inclination angle, etc.) of the bridge key nodes are collected in real time. The system calculates the residual between these measured values and the dynamic safety threshold envelope in real time. The residual is the difference between the actual measured value of the sensor and the theoretical value calculated by the model.

[0067] When the system detects that the residual exceeds the allowed range (i.e., the residual is over-limit), the energy dissipation feature of the measured data is extracted to determine whether the structure shows a trend of abnormal energy accumulation or release.

[0068] The instability determination and blocking step: according to the energy dissipation feature, it is determined whether the structure is in an irreversible instability collapse stage; if instability is determined, a blocking instruction is generated before the bridge structure collapses physically and causes the pipeline to reach the tensile limit.

[0069] The system determines the stability of the structure based on the extracted energy dissipation feature, and confirms whether the structure has entered an irreversible instability collapse stage. Irreversible instability collapse refers to the structure having crossed the critical point of elastic recovery and will inevitably collapse physically.

[0070] Once the determination result is "instability", the system will execute the pre-emptive control strategy: in the process of physical collapse of the bridge structure, and before the pipeline attached to the bridge reaches the tensile limit (i.e., the pipeline is physically torn), a blocking instruction is immediately generated to ensure that the control signal is sent earlier than the time of physical damage.

[0071] The emergency execution step: using the blocking instruction to trigger the action of the circuit breaking mechanism pre-installed at both ends of the municipal pipe gallery, cutting off the transmission lines inside the pipe gallery, and simultaneously triggering the traffic blocking signal and emergency data broadcast.

[0072] Using the above generated blocking instruction, the circuit breaking mechanism pre-installed at both ends of the municipal pipe gallery (i.e., in the non-collapse area) is directly triggered to act, thereby physically cutting off the transmission lines (such as power, gas, etc.) inside the pipe gallery, preventing secondary disasters caused by pipeline rupture.

[0073] At the same time, the system synchronously triggers the traffic blocking signal to prevent vehicles from entering the danger zone, and starts the emergency data broadcast to send alarm information to the outside world.

[0074] Example Two

[0075] The embodiment details the dynamic reference construction step, specifically including:

[0076] S11, bridge construction is a process of continuous conversion of structural system (for example: from T cantilever stress conversion for continuous beam stress), in order to accurately simulate this process, the construction process progress data is discretized into Process nodes, the process nodes correspond to different structural system conversion state, such as: the Segment reinforcement binding, the Segment concrete pouring, the Segment prestressed tension.

[0077] S12, according to the process node type of the current time, real-time update the stiffness matrix of the structure finite element model, and introduce the real-time construction load vector, calculate the theoretical state reference value under the current working condition;

[0078] Based on the finite element method (FEM), the structure equilibrium equation changes with time At any time , belongs to the Process node, the current theoretical state reference value vector Is calculated by the following stiffness balance equation: .

[0079] Wherein: : represents the theoretical state reference value vector at time , including the theoretical displacement (such as midspan deflection) and theoretical angle of key nodes.

[0080] : represents the global structure stiffness matrix corresponding to the Process node. The matrix is updated in real time according to the BIM model, reflecting the geometric topology structure of the bridge at the current time (such as whether the closure) and the material properties (such as the elastic modulus of concrete With the growth of age).

[0081] : represents the real-time construction load vector, including the self weight of hanging basket, wet concrete weight and dynamic position load of construction machine.

[0082] : represents the environmental basic load vector, mainly refers to the constant structure dead weight and foundation wind load.

[0083] By solving the above equation, the theoretical state reference value considering only the mechanical stress can be obtained: .

[0084] S13, collect the cross-section temperature gradient data of the bridge structure, calculate the temperature additional deformation amount by using the preset thermal sensitivity coefficient, superimpose the temperature additional deformation amount to the theoretical state reference value, and obtain the corrected dynamic reference value.

[0085] Since the bridge structure is sensitive to temperature changes, the pure mechanical model cannot separate the temperature deformation, so the temperature compensation term is introduced to eliminate the influence of non-disaster environmental thermal expansion and cold contraction.

[0086] Collect the temperature data of the bridge cross-section, define the temperature additional deformation amount The calculation model is as follows:

[0087] Among them: : represents the cross-section average effective temperature at time .

[0088] : represents the reference temperature of the closed or initial state of the structure.

[0089] : represents the cross-section temperature gradient in the direction of the beam height at time .

[0090] : represents the uniform temperature difference influence coefficient matrix, which represents the sensitivity of the structure to expansion and contraction deformation due to overall temperature rise and fall. It is obtained by regression training of historical monitoring data.

[0091] : represents the gradient temperature difference influence coefficient matrix, which represents the sensitivity of the structure to flexural deformation due to the temperature difference between the upper and lower surfaces. It is obtained by regression training of historical monitoring data.

[0092] Obtain the corrected dynamic reference value : .

[0093] S13, identify the operation type of the current process node, and the operation type at least includes the static curing stage and the dynamic operation stage; select the corresponding process disturbance factor according to the operation type, wherein the process disturbance factor value of the dynamic operation stage is greater than that of the static curing stage;

[0094] Identify the operation type of the current process node, and select the process disturbance factor accordingly .

[0095] When it belongs to the dynamic operation stage, When it belongs to the static curing stage, . Among them, (for example, 1.5, Taking 4.0), that is, loosening the threshold in the dynamic operation period and tightening the threshold in the static period.

[0096] S14, multiplying the sensor inherent noise reference value by the process disturbance factor to calculate the dynamic safety bandwidth, superimposing the dynamic safety bandwidth on the upper and lower boundaries of the dynamic reference value to generate the dynamic safety threshold envelope.

[0097] The calculation time The dynamic safety bandwidth : .

[0098] Where: : represents the sensor inherent noise reference value (usually taking 3 times the standard deviation of the sensor accuracy, such as ).

[0099] : represents the minimum safety redundancy constant of the system.

[0100] Finally, the dynamic safety threshold envelope is generated, including the upper limit and the lower limit : .

[0101] Example Three

[0102] This embodiment describes the precursor feature recognition step in detail. By introducing a dual verification mechanism of macroscopic kinetic energy and microscopic damage, a high-confidence early warning logic is constructed.

[0103] S21, the inclination data of the key node is parsed from the motion state data, the angular velocity is calculated by differentiation, and the phase plane trajectory based on inclination and angular velocity is constructed.

[0104] The real-time inclination of the key node (such as the cantilever end of the bridge) is parsed from the motion state data . The angular velocity is calculated by using the difference or differential filter .

[0105] A two-dimensional state vector is constructed, and its evolution trajectory is plotted on the phase plane.

[0106] S22, calculating the dynamic instability index of the structure, the dynamic instability index representing the nonlinear divergence degree of the structure rotation kinetic energy relative to the gravitational potential energy barrier;

[0107] Define the total energy function of the system . For a single-degree-of-freedom inverted pendulum model (simulating a cantilever structure), its energy is composed of kinetic energy and gravitational potential energy: .

[0108] wherein: : moment of inertia of the structure.

[0109] : equivalent mass of the structure.

[0110] : distance from the center of gravity to the center of rotation.

[0111] : acceleration of gravity.

[0112] Define dynamic instability index : .

[0113] wherein, is the remaining potential energy barrier that needs to be overcome for the current position to reach the overturning critical angle .

[0114] When the structure is in stable oscillation, the energy is converted between kinetic and potential energy, and remains at a low level; when the structure is unstable, the kinetic energy continues to increase and the potential energy constraint fails, and will show a nonlinear exponential growth.

[0115] The dynamic instability index is taken as the macroscopic kinetic energy dissipation component;

[0116] S23, parse the high-frequency acceleration signal from the motion state data, and perform frequency domain decomposition to separate the high-frequency acoustic emission component representing material internal fracture.

[0117] Collect high-frequency acceleration signals , and perform fast Fourier transform (FFT) or wavelet packet decomposition (WPD) to filter out low-frequency components representing environmental vibrations (such as wind load, traffic flow, usually ) and separate high-frequency acoustic emission components representing material internal micro-crack propagation (frequency band usually even higher).

[0118] S24, calculate the impact index of the high-frequency acoustic emission component using the statistical fourth moment algorithm.

[0119] The fourth central moment in statistics is used to quantify the impact characteristics of the signal. Normally distributed random vibration (such as background noise) has a kurtosis value close to 3, while signals containing fracture impacts have a thick-tailed characteristic and the kurtosis value will increase significantly. Calculate the impact index : .

[0120] wherein: : time window The acoustic emission signal sampling point inside.

[0121] The signal mean value.

[0122] The signal standard deviation.

[0123] The numerator is the fourth central moment, and the denominator is the square of the second central moment (variance).

[0124] The impact index is taken as the micro-damage divergence component.

[0125] S25, when the phase plane trajectory breaks through the stable limit cycle and the dynamic instability index grows, it is determined that the macro kinetic energy divergence component is effective.

[0126] As Figure 3 shown, the phase plane trajectory is monitored, if the trajectory breaks through the pre-labeled stable limit cycle (i.e. the maximum phase trajectory envelope under normal working conditions), and the is detected synchronously exponentially increases (i.e. and ), it is determined that the macro kinetic energy divergence component is effective.

[0127] The horizontal axis represents the inclination angle of the key node, and the vertical axis represents the inclination rate (angular velocity). The closed loop trajectory (inner circle) in the figure represents the stable limit cycle, indicating the normal elastic swing of the structure under the action of wind load or vehicle load, and the energy is conserved and converted between kinetic energy and potential energy. The outward diverging spiral trajectory (outer circle) represents the energy divergence state. When the monitored real-time trajectory breaks through the boundary of the stable limit cycle and does not return to the origin but expands outward exponentially, corresponding to the growth of the dynamic instability index as described above, the system determines that the macro kinetic energy divergence component is effective.

[0128] When the impact index exceeds the preset structure damage threshold, it is determined that the micro-damage divergence component is effective.

[0129] The impact index is monitored. If is a preset structure damage threshold, for example, it is 5 or more, indicating the occurrence of non-Gaussian impact, it is determined that the micro-damage divergence component is effective.

[0130] S26, using a logical AND gate mechanism, when the macro kinetic energy divergence component and the micro-damage divergence component are simultaneously determined to be effective, it is confirmed that the energy divergence feature is extracted, and it is determined that the structure enters an irreversible unstable state.

[0131] Macroscopic indicators can identify "moving", microcosmic indicators can identify "broken", the combination of the two (logical and) can effectively eliminate the interference of "blown by strong wind but not broken" (macroscopic without microcosmic) or "local blockage but stable main body" (microcosmic without macroscopic), so as to accurately lock the real overall collapse accident.

[0132] Embodiment four

[0133] This embodiment describes the instability determination and blocking steps in detail.

[0134] S31, while collecting the structure motion state data, the voltage drop rate of the system main power supply loop is monitored in real time.

[0135] The system configures a high-frequency voltage sampling module in the main power supply loop, and sets The voltage of the main loop at the moment is The system calculates the voltage change rate with time, that is, the voltage drop rate , wherein is the sampling interval.

[0136] S32, set the physical cut-off threshold corresponding to the voltage drop rate, and the physical cut-off threshold is greater than the voltage drop rate of the natural depletion of the battery.

[0137] In order to distinguish between normal depletion of the battery and physical breakage of the line, two thresholds are set:

[0138] Natural depletion slope : the slow voltage drop rate when the battery power is depleted (usually mV / h level).

[0139] Physical cut-off threshold : the voltage transient drop rate when the power supply line is physically broken or short-circuited (usually V / ms level). And .

[0140] The system performs the following comparison logic: if , it is determined that the power supply loop is physically damaged.

[0141] S33, when the energy dissipation feature is confirmed, or the voltage drop rate is monitored to exceed the physical cut-off threshold, it is determined that the structure is in the instability collapse stage, and the blocking program is immediately activated.

[0142] The system adopts "logical or" architecture for final instability determination. Whether it is the calculated structure instability (soft criterion) or the monitored power supply line breakage (hard criterion), as long as one of them is met, the system immediately activates the blocking program.

[0143] ​It ensures that even if the monitoring probe falls with the beam body, the power line breakage can serve as the last alarm signal.

[0144] S34, in order to ensure that the blocking instruction takes effect before the pipeline is pulled off, a time window calculation model must be established.

[0145] According to the geometric structure and material elongation rate of the bridge pipe gallery, the theoretical safety time window required for the pipeline to free fall to the physical pull-off limit height of the bridge is calculated.

[0146] According to the geometric structure of the pipe gallery and the material properties of the pipeline, the maximum falling displacement that the pipeline can withstand is calculated. Assuming that the ultimate elongation of the pipeline material is (e.g. the yield elongation of steel pipe), the initial length of the pipeline between the two end anchor points is . The maximum arc length allowed by the pipeline before breaking is: .

[0147] Assuming that the bridge falls vertically at the midspan, according to the geometric relationship (such as the Pythagorean theorem), the maximum falling height of the bridge allowed by the pipeline without breaking : .

[0148] The calculation of the theoretical safety time window assumes that the bridge collapse is a free fall motion. According to the kinematics formula , the time required for the structure to fall from the beginning of instability to reach , that is, the theoretical safety time window : , where is the acceleration of gravity.

[0149] S35, the total time of the system control to generate and send the blocking instruction, including the sum of the sampling filtering time, the algorithm calculation time and the breaker mechanical action time, and the total time is less than the theoretical safety time window.

[0150] In order to ensure the pre-emptive blocking, the total response time of the system must be less than the theoretical safety time window. Composed of the following parts: .

[0151] Among them: : sensor sampling and filtering delay.

[0152] : algorithm calculation and logical judgment time.

[0153] : instruction sending and transmission delay.

[0154] Time for a breaker mechanism (such as solenoid, relay) to complete a mechanical action from receiving an electrical signal.

[0155] Therefore, the constraint condition needs to be met: In the system design phase, it must be ensured to meet the above inequality by selecting high-frequency processors, low-latency communication modules, and fast cut-off valves. For example, if it is calculated that , then the total time consumption of the system should be designed to be controlled within 1.0s, leaving a safety margin of 0.5s.

[0156] Example five

[0157] This embodiment specifically describes the emergency execution steps. When the bridge collapses substantially, causing the conventional power supply to be cut off and the conventional communication link to be unstable, the alarm information is ensured to be sent out and the on-site blocking is executed. Specifically, it includes:

[0158] Emergency energy release mode switching: when receiving the blocking instruction or determining that the main power loop fails, the system cuts off the power supply of the conventional sensor, forces the pre-installed transient high-power energy storage loop to be turned on, and uses the high-density energy released by it to take over the power supply of the communication module.

[0159] In the normal monitoring state, the system pursues low power consumption to maintain long endurance. However, at the moment of collapse, the conventional power line (mains) is usually pulled off instantly, and the on-board lithium battery may not have enough capacity for high-current discharge.

[0160] The core component of the transient high-power energy storage loop is usually a super capacitor module.

[0161] When the central processor receives the "blocking instruction" (from the determination of example four) or detects the "main power loop failure" (voltage drops to zero) through the hardware watchdog circuit, the system immediately performs the following actions:

[0162] Load shedding: cut off the power supply of all non-core sensors (such as cutting off the total station, high-definition camera, and other high-energy-consuming collection devices that are meaningless at this time) through solid-state relays to prevent invalid power consumption.

[0163] Forced conduction: close the high-frequency switch to connect the pre-charged super capacitor to the main power bus and completely take over the power supply task of the communication module. Use the high-density energy released by the super capacitor instantaneously to support the subsequent high-power signal transmission.

[0164] Protocol degradation and compression: suspend the conventional full waveform data transmission protocol and generate a minimalist SOS data packet containing only the device identity code, collapse trigger time, and accident type code.

[0165] Routine monitoring data contains high-sampling-rate waveform files, usually in the order of megabytes (MB), which takes a long time to transmit and requires a complete TCP / IP handshake protocol. This step performs protocol downgrade logic:

[0166] Abort transmission: Immediately interrupt all ongoing routine data upload tasks, and discard unsent waveform buffers.

[0167] Generate SOS packet: Assemble a minimal SOS data packet. This packet contains only the most critical metadata, without any waveform payload. Its typical structure is as follows:

[0168] Device identity code: 4 bytes, identifying which bridge and which node the device is.

[0169] Collapse trigger time: 8 bytes, accurate to milliseconds, for post-accident recovery.

[0170] Accident type code: 1 byte, for example, 0x01 represents macro kinetic energy dispersion, 0x02 represents microscopic damage overrun, and 0x03 represents physical tearing of the power line.

[0171] Compress the amount of data to be transmitted from MB level to tens of bytes, and complete the transmission within a few milliseconds.

[0172] Saturated power broadcast: Remove the regular power consumption limit of the wireless transmission module, and adjust the transmit power gain to the maximum saturation value allowed by the hardware. Within the survival time window of the device falling freely with the bridge, the minimal SOS data packet is broadcasted cyclically through the local wireless link and the remote communication link.

[0173] In order to ensure that the SOS data packet can be received, the regular power consumption limit rule is broken.

[0174] Remove the limit: Software shields the automatic gain control (AGC) and energy-saving algorithm of the radio frequency (RF) module.

[0175] Saturated transmission: Adjust the gain of the power amplifier (PA) to the absolute maximum value allowed by the hardware (saturation region).

[0176] Cyclic broadcast: Within the survival time window of the device falling freely with the bridge, the above SOS data packet is broadcasted cyclically through the local wireless link (such as LoRa / Zigbee, which wakes up nearby devices) and the remote communication link (such as 4G / 5G / Beidou short message).

[0177] On-site physical lockout execution: Use the hardware I / O interface (such as GPIO or relay output) of the edge gateway to directly drive the on-site sound and light alarm to start a high-decibel alarm, and simultaneously turn on the car lane LED no-entry light, achieving millisecond-level on-site traffic physical blocking before remote management intervention.

[0178] Embodiment six

[0179] A safety early warning terminal for monitoring collapse of a comprehensive bridge under construction, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the safety early warning method for monitoring collapse of a comprehensive bridge under construction as described above when executing the computer program.

[0180] The memory can be used to store software programs and modules, and the processor executes various functions of the terminal and data processing by running the software programs and modules stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one execution program required by a function, etc.

[0181] The data storage area can store data created according to the use of the terminal, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device.

[0182] A computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the safety early warning method for monitoring collapse of a comprehensive bridge under construction as described above.

[0183] Without loss of generality, the computer readable medium can include computer storage media and communication media. The computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer readable instructions data structures, program modules or other data. Computer storage media includes RAM, ROM, EPROM, EEPROM, flash memory or other solid state storage technology, CD-ROM, DVD or other optical storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device. Of course, those skilled in the art can know that the computer storage medium is not limited to the above several. The system memory and mass storage device described above can be collectively referred to as memory.

[0184] A computer program product, comprising computer programs / instructions, which are executed by a processor to implement the safety early warning method for monitoring collapse of a comprehensive bridge under construction as described above.

[0185] A computer program product includes a computer program or a set of instructions for performing a particular task or implementing a particular abstract data type. These programs or instructions are designed and constructed for execution by a processor, thereby implementing a series of predefined steps or operations. The program product can be stored in various forms of computer storage media, such as memory, hard disk, solid state drive, optical disc, or other forms of digital storage devices. It can exist in the form of compiled binary code or in the form of scripts or bytecodes executable by an interpreter. The program product, through carefully designed algorithms and logical instructions, enables the processor to process data in a specific order and manner, complete various functions such as data analysis, user interaction, device control, etc.

[0186] In the description of the present specification, the description of the terms "one embodiment / way", "some embodiments / ways", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / way or example are included in at least one embodiment / way or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments / ways or examples. In addition, the person skilled in the art can combine and combine the different embodiments / ways or examples described in the present specification and the features of the different embodiments / ways or examples, without contradiction.

[0187] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0188] Those skilled in the art should understand that the above embodiments are only for the purpose of clearly illustrating the present application, and are not intended to limit the scope of the present application. Other changes or modifications can be made to the above embodiments by those skilled in the art, and these changes or modifications are still within the scope of the present application.

Claims

1. A method for monitoring and providing early warning of collapse of a comprehensive bridge under construction, characterized in that, Includes the following steps: Dynamic benchmark construction steps: Obtain the current construction process progress data of the bridge, establish a time-varying mechanical model of the structure that evolves with the process, and combine environmental thermal effect compensation to generate a dynamic safety threshold envelope that is adapted to the current working conditions. Precursor feature identification steps: Real-time acquisition of motion state data of key bridge nodes, calculation of the residual between the measured value and the dynamic safety threshold envelope; when the residual exceeds the limit, extraction of energy divergence features of the measured data; Instability determination and blocking steps: Based on the energy dissipation characteristics, determine whether the structure is in an irreversible unstable and collapsing stage; If the bridge structure is determined to be unstable, a blocking command will be generated before the pipeline reaches its tensile limit due to a physical collapse of the bridge structure. Emergency Execution Steps: The blocking command is used to trigger the circuit breaker mechanisms pre-installed at both ends of the municipal utility tunnel to cut off the transmission lines inside the tunnel, and simultaneously trigger traffic closure signals and emergency data broadcasts. The specific methods for establishing the time-varying mechanical model of the structure in the dynamic benchmark construction step include: The construction process progress data is discretized into multiple process nodes, and each process node corresponds to a different structural system transformation state. Based on the current process node type, the stiffness matrix of the structural finite element model is updated in real time, and the real-time construction load vector is introduced to calculate the theoretical state reference value under the current working condition. Collect cross-sectional temperature gradient data of the bridge structure, calculate the temperature-induced deformation using a preset thermal sensitivity coefficient, and superimpose the temperature-induced deformation onto the theoretical state reference value to obtain the corrected dynamic reference value. The method for generating the dynamic safety threshold envelope in the dynamic benchmark construction step includes: Identify the operation type of the current process node, wherein the operation type includes at least the static curing stage and the power operation stage; Select the corresponding process disturbance factor according to the type of operation, where the process disturbance factor value of the power operation stage is greater than that of the static curing stage. The dynamic safety bandwidth is calculated by multiplying the sensor's inherent noise reference value by the process disturbance factor. The dynamic safety bandwidth is then superimposed on the upper and lower boundaries of the dynamic reference value to generate the dynamic safety threshold envelope.

2. The method for monitoring and providing early warning of collapse of an integrated bridge under construction as described in claim 1, characterized in that, The energy divergence features extracted in the precursor feature identification step include macroscopic kinetic energy divergence components and microscopic damage divergence components; The method for extracting the macroscopic kinetic energy divergence component includes: The tilt angle data of key nodes is parsed from the motion state data, and the angular velocity is obtained through differential calculation to construct a phase plane trajectory based on the tilt angle and angular velocity; The dynamic instability index of the structure is calculated, which characterizes the degree of nonlinear divergence of the rotational kinetic energy of the structure relative to the gravitational potential energy barrier. The dynamic instability index is used as the macroscopic kinetic energy divergence component. The method for extracting the divergent components of the micro-damage includes: The high-frequency acceleration signal is extracted from the motion state data, and its frequency domain is decomposed to separate the high-frequency acoustic emission component representing the internal fracture of the material. The impact index of the high-frequency acoustic emission component was calculated using the statistical fourth-order moment algorithm; The impact index is used as the micro-damage divergence component.

3. The method for monitoring and providing early warning of collapse of an integrated bridge under construction according to claim 2, characterized in that, The specific methods for extracting energy divergence features include: When the phase plane trajectory is detected to have broken through the stability limit cycle and the dynamic instability index is increasing, the macroscopic kinetic energy divergence component is determined to be effective. When the impact index exceeds the preset structural damage threshold, the micro-damage divergence component is determined to be valid. Using an AND gate mechanism, when the macroscopic kinetic energy divergence component and the microscopic damage divergence component are simultaneously determined to be valid, the energy divergence feature is confirmed to have been extracted, and the structure is determined to have entered an irreversible unstable state.

4. The method for monitoring and providing early warning of collapse of an integrated bridge under construction according to claim 1, characterized in that, The methods for determining instability in the instability determination and blocking steps specifically include: A physical cutoff threshold is set corresponding to the voltage drop rate, and the physical cutoff threshold is greater than the voltage drop rate of the battery naturally depleting; While collecting structural motion state data, the voltage drop rate of the system's main power supply circuit is monitored in real time. When the energy dissipation characteristics are confirmed, or when the voltage drop rate is detected to exceed the physical cutoff threshold, the structure is determined to be in an unstable and collapsing stage, and the blocking procedure is immediately activated.

5. The method for monitoring and providing early warning of collapse of an integrated bridge under construction according to claim 4, characterized in that, The generation of blocking instructions in the instability determination and blocking steps must satisfy time window constraints, specifically including: Based on the geometry and elongation of the bridge utility tunnel, the theoretical safe time window required for the pipeline to fall freely from the bridge to its physical tensile strength limit is calculated. The total time taken for the system to generate and send the blocking command includes the sum of sampling and filtering time, algorithm calculation time, and circuit breaker mechanical action time, and the total time is less than the theoretical safe time window.

6. The method for monitoring and providing early warning of collapse of an integrated bridge under construction according to claim 1, characterized in that, The emergency response steps specifically include: Emergency energy release mode switching: When the blocking command is received or the main power circuit is determined to be faulty, the system cuts off the power supply to the conventional sensors, forcibly turns on the preset transient high-power energy storage circuit, and uses the high-density energy released by it to take over the power supply to the communication module. Protocol downgrade and compression: The conventional full waveform data transmission protocol is terminated, and a minimal SOS data packet containing only the device identification code, collapse trigger time, and accident type code is generated; Saturation Power Broadcast: Remove the conventional power consumption limit of the wireless transmission module, adjust the transmit power gain to the maximum saturation value allowed by the hardware, and broadcast the simplified SOS data packet cyclically through the local wireless link and the remote communication link within the survival time window of the device during the free fall of the bridge.

7. The method for monitoring and providing early warning of collapse of an integrated bridge under construction according to claim 6, characterized in that, Emergency response procedures also include: On-site physical blockade execution: The hardware I / O interface of the edge gateway is used to directly drive the on-site audible and visual alarm to activate a high-decibel alarm and simultaneously light up the lane LED no-entry lights, achieving millisecond-level on-site physical traffic blockade before remote management intervention.

8. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the method for monitoring and providing early warning of the collapse of an integrated bridge under construction as described in any one of claims 1-7.

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