Automatic dismantling system for cofferdam construction

Abstract

The invention discloses an automatic demolition system for cofferdam construction, and relates to the technical field of hydraulic cofferdam demolition, and the automatic demolition system is characterized in that pressure measuring points are arranged inside and outside a cofferdam, the same differential pressure measuring unit is connected, clogging and turbulence interference are inhibited by combining a static water well and a controllable flushing branch, and measurement credibility gating is formed by adopting internal and external water level checking; when the credibility is met, a water head difference safety window and a change speed upper limit are loaded, a pump drainage pump and a recharge valve group are adjusted in a closed-loop mode, a controlled pressure equalizing bypass channel is arranged, and automatic flow limiting and pressure equalizing are achieved during overrun, uncredible measurement or control failure; operation permission is generated according to the binding boundary of the dismantling stage, double-channel hardware is connected into a dismantling equipment enabling loop in an interlocking mode, and permission is revoked and degradation mark leaving is carried out when abnormity occurs. According to the scheme, the water head difference judgment reliability is improved, the water head difference and the change speed are limited, the misoperation and sudden water inflow risks are reduced, and the dismantling continuity and traceability are enhanced.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cofferdam demolition technology, specifically to an automated demolition system for cofferdam construction. Background Technology

[0002] Cofferdams are mainly used for foundation construction and maintenance water isolation in river channels, lakes, nearshore and urban waterfront projects. Common forms include steel sheet pile cofferdams, double-walled steel cofferdams, and earth-rock cofferdams. During the demolition phase, the cofferdam needs to be removed and recovered around the original foundation or abutment. This typically occurs in confined spaces, near-water environments, and multi-trade complex environments. On the one hand, the work platform, walers, and internal supports need to be dismantled; on the other hand, the water level relationship inside and outside the cofferdam needs to be changed through dewatering or phased backwatering to meet the requirements of structural stress, lifting, vibration, and cutting during demolition. In some tidal areas, the head difference generated by the rise and fall of the external water level can also be used to detach the cofferdam from the bottom or foundation. Currently, most demolition organizations rely on on-site personnel to judge based on experience using water level gauges, pressure gauges, or monitoring instrument readings, and adjust pump sets and valves as needed. Some solutions introduce water level monitoring and early warning platforms to collect and display information on the water level difference inside and outside the cofferdam, structural stress, or displacement to assist in safety management and process recording. The above-mentioned technical approach can provide some informational assistance, but given the high degree of coupling between the demolition process and water level regulation, as well as the rapid changes in the external water level, there may still be problems such as delayed determination of head difference, inconsistent data sources, and difficulty in directly supporting the determination of on-site operation boundaries with monitoring results.

[0003] This problem often occurs after the removal of internal supports or walers, when the stiffness of the cofferdam structure decreases and the stress path changes. The head difference affects the hydrostatic pressure difference inside and outside the cofferdam, as well as the lateral stress and seepage gradient of the retaining structure. When the external water level is affected by tides, gate scheduling, or flood events, and the pumping or return water on the inside is affected by transients, return water velocity, and local short-circuit flow caused by pump start-stop, the head difference changes rapidly and nonlinearly. In addition, the high sediment content, floating debris and air bubbles in the water inside and outside the cofferdam, as well as the blockage of pressure tapping channels or hydrostatic pipes, lead to measurement response lag, drift, or intermittent failure, resulting in a large difference between the head difference and the displayed value.

[0004] If the head difference exceeds the design limit within a short period, it will cause seepage accumulation, piping, bottom heave, or local instability. This, combined with high-risk operations such as dismantling, hoisting, vibration, and cutting, may lead to sudden water ingress, abnormal component stress, equipment shutdown, or construction safety accidents, resulting in project delays, surrounding disturbances, and increased costs. Therefore, during cofferdam dismantling, issues such as external water level fluctuations, transient pumping and return water, and measurement distortion make it impossible for existing technologies to consistently obtain reliable internal and external head difference criteria and determine the safety boundaries of dismantling operations. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides an automated dismantling system for cofferdam construction. This system loads a safety window for head difference and an upper limit for the rate of change when reliability is satisfied, regulates the pumping and recharge valve groups in a closed loop, and sets up a controlled pressure equalization bypass channel. It automatically limits flow and equalizes pressure when limits are exceeded, measurements are unreliable, or control fails. Work permits are generated according to the boundaries of each dismantling stage, and dual-channel hardware interlocks are connected to the dismantling equipment enable circuit. In case of anomalies, permits are revoked and downgraded with a record, limiting head difference and rate of change, reducing the risk of misoperation and sudden water ingress. This system solves the technical problems described in the background art.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] An automated dismantling system for cofferdam construction includes: pressure tapping points inside and outside the cofferdam; pressure tapping pipelines connected to the same differential pressure measurement unit; a control unit converting the internal and external pressure difference into the internal and external water head difference; the pressure tapping points are equipped with static wells or pressure tapping chambers and controllable flushing branches, and the internal and external water levels are collected for consistency verification to form a measurement reliability judgment.

[0010] When the measurement reliability judgment is met, the control unit loads the range of internal and external head difference and the upper limit of the head difference change rate, and uses the internal and external head difference as feedback to adjust the pump speed and the opening of the recharge valve group; a controlled pressure equalization bypass channel is set up, and when the head difference or change rate exceeds the limit, the measurement is unreliable or the control unit fails, the controlled pressure equalization bypass channel is used to limit the flow and equalize the pressure.

[0011] The dismantling process is divided into stages, binding the range of internal and external head difference and the upper limit of the rate of change of head difference; the control unit determines the dismantling operation permit based on the measurement reliability, the internal and external head difference and the rate of change of head difference, and the dual-channel hardware interlock is connected to the dismantling equipment enable circuit, and the permit is revoked and downgraded.

[0012] Furthermore, the still water well or pressure tapping chamber is fixed to the cofferdam component, with a protective grid on the outside and a sedimentation zone formed inside. The pressure tapping point is equipped with a pressure tapping nozzle, and the inlet face is perpendicular to the main flow direction and arranged in a position that avoids the sedimentation zone. The pressure tapping pipeline is equipped with an exhaust port and a sewage outlet, and is connected to an exhaust valve and a sewage outlet respectively. An exhaust chamber is formed at the top of the still water well and is connected to the exhaust port.

[0013] Furthermore, the controllable flushing branch and the pressure tapping pipeline are connected in parallel and include a flushing valve and a drain valve. When the predetermined cycle is reached, the control unit first puts the pump and the recharge valve group into a safe state, then opens the flushing valve and the drain valve to complete the backflushing. After the backflushing is completed, the exhaust valve is opened briefly to vent and the pressure tapping is restored.

[0014] Furthermore, when the differential pressure-converted head difference and the water level-converted head difference continue to deviate and the head difference response is delayed after the pumping and recharge action, the control unit determines that the measurement reliability judgment is not met, triggers backwashing of the controllable flushing branch, and re-executes the consistency check and writes it into the flushing self-test record after the backwashing is completed.

[0015] Furthermore, the internal and external water level measurement units output water level records with timestamps. The control unit caches the water level records and uses the sampling time of the differential pressure measurement unit as a reference to perform piecewise linear interpolation alignment on the internal and external water levels respectively, calculates the water level difference to convert the head difference, and forms a measurement reliability judgment based on this.

[0016] Furthermore, after loading the internal and external head difference range, the control unit generates a reference head difference and combines the internal and external head difference deviation with the head difference change rate to form a joint control command. The joint control command is mapped to the pump speed setting value and the recharge valve group opening setting value according to positive and negative, respectively, and the change rate of the setting value is limited.

[0017] Furthermore, the controlled equalization bypass channel includes a bypass pipeline, a current limiting element, and a fault default safety valve. The current limiting element and the fault default safety valve are arranged in series on the bypass pipeline. When the control unit loses power, the fault default safety valve returns to the preset safety opening degree, which is the current limiting opening degree and keeps the bypass pipeline connected with current limiting.

[0018] Furthermore, the control unit determines the degree of non-compliance based on the degree of internal and external head difference exceeding the limit, the degree of head difference change rate exceeding the limit, and the measurement reliability, and sets the bypass trigger index, bypass opening threshold, bypass closing threshold, and bypass confirmation time. When the bypass trigger index meets the opening conditions, the fault default safety valve is driven to open to the flow-limiting opening degree. When the closing conditions are met, it returns to the preset safety opening degree.

[0019] Furthermore, the dismantling phase is linked to the range of internal and external head difference and the upper limit of the rate of change of head difference. The control unit freezes and stores boundary snapshots when switching dismantling phases, and uses the boundary snapshots as the sole parameter source for determining the dismantling operation permit. The issuance of the dismantling operation permit adopts the continuous and stable entry condition, and the retention adopts the grace period retention condition.

[0020] Furthermore, the dual-channel hardware interlock is connected in series with two independent contacts to the dismantling equipment enable circuit, and the auxiliary contacts of the dismantling equipment contactor are collected as feedback. When the on / off state of the dual-channel hardware interlock is inconsistent with the feedback, the dismantling operation permit is revoked, and the degradation is performed in the order of interlock disconnection, pumping and recirculation to enter the safe state, and bypass current limiting and equalization. At the same time, a record entry containing the dismantling stage, boundary snapshot and trigger reason is written.

[0021] (III) Beneficial Effects

[0022] This invention provides an automated dismantling system for cofferdam construction, which has the following advantages:

[0023] Pressure taps are located both inside and outside the cofferdam, connected to a differential pressure measurement unit via pressure tapping pipelines. The control unit converts the internal and external pressure difference into the internal and external water head difference. Each pressure tap is equipped with a stilling well or pressure tapping chamber, a protective grid, a sedimentation zone, and a controllable flushing branch. The pressure tapping channel is not blocked by air bubbles or silt, and the internal and external water head differences originate from the same and stable source. Internal and external water level measurement units are set up in parallel. The control unit performs consistency verification on the water level data to determine the measurement reliability. This determination is used as an entry condition for pumping, reinjection, and dismantling; pumping is stopped, controlled pressure equalization is implemented, flushing and self-inspection are performed, and further dismantling is prohibited.

[0024] The control unit loads the range of internal and external head difference and the upper limit of the rate of change of head difference at different stages of dismantling. It uses the internal and external head difference as a feedback closed loop to adjust the speed of the pumping pump and the opening of the reinjection valve group, and limits the rate of change of the set value. When the external water level fluctuation is superimposed with the transient state of the pump and valve, the head difference and the head difference change process are subject to boundary constraints.

[0025] Controlled pressure equalization bypass channels are set up inside and outside the cofferdam for pumping and recharge valve groups. The bypass channels are connected in series with flow limiting elements and fault default safety valves. When the head difference or change rate exceeds the limit, the measurement is unreliable, or the control unit fails, the flow limiting pressure equalization is triggered. In the event of power failure or abnormal control link, there is still an independent pressure equalization channel and the flow is limited and connected.

[0026] During dismantling, the internal and external head difference range and the upper limit of the head difference change rate are bound in three stages, and the boundary snapshot is frozen. The control unit determines the dismantling operation permit based on the measurement reliability, the internal and external head difference and the head difference change rate, and connects to the dismantling equipment enable circuit with dual-channel hardware interlock. In accordance with the revocation of the permit and the downgrade sequence, pumping, recharge and pressure equalization are linked and the head difference curve, threshold envelope and the reason for the permit change are recorded. Together, the measurement, equalization and permit form a closed loop. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the automated dismantling system for cofferdam construction according to the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1 This invention provides an automated dismantling system for cofferdam construction, comprising:

[0030] Step 1: Under the conditions of silt, air bubbles and turbulence coexisting during the cofferdam removal stage, establish a self-sustaining and verifiable internal and external head difference measurement link, and use the measurement reliability as a prerequisite for subsequent removal actions.

[0031] Frequent pumping and backflow during cofferdam removal can easily cause surges and backflows on the water surfaces inside and outside the cofferdam. If the pressure tap is directly exposed to the main flow field, dynamic pressure disturbances may be superimposed on the pressure tapping pipeline, resulting in spikes and jumps in the differential pressure measurement unit output. If the pressure tap is periodically blocked by floating debris or silt, the signal will experience hysteresis and intermittent distortion. These phenomena are more likely to occur before and after the removal of supports and cofferdam components, making it difficult to distinguish between the actual head difference change and measurement link anomalies on site. Therefore, it is necessary to first limit the pressure tapping environment to be predominantly static pressure and not easily blocked at the physical level.

[0032] The hydrostatic pressure is collected from pressure taps on both the inner and outer sides of the cofferdam. The collected pressures are then fed into the same differential pressure measurement unit via pressure tapping pipelines, causing the differential pressure measurement unit to output the internal and external pressure difference. The control unit uses this internal and external pressure difference as the main signal to complete the conversion of the internal and external water head difference and writes it into the measurement baseline. Subsequent flushing, self-testing, and reliability gating are all referenced to this measurement baseline.

[0033] To prevent air bubbles from accumulating and creating false pressure differentials, the pressure tapping lines are organized as monotonically venting paths; to prevent sediment from entering the diaphragm chamber of the differential pressure measurement unit, the pressure tapping lines are organized as monotonically draining paths. Subsequently, the pressure tapping points are isolated from the main flow field through a static well or pressure tapping chamber, making the pressure entering the pressure tapping lines closer to the static pressure, thereby providing a stable input for self-maintenance diagnostics.

[0034] Using the same differential pressure measurement unit as the convergence point for internal and external pressure taps ensures that the internal and external pressure tap signals are compared under the same measurement reference, thus avoiding the superposition of zero-point drift from the two independent sensors.

[0035] During construction, pressure taps are first installed at the pressure tapping points inside the cofferdam, with the inlet face of the pressure taps perpendicular to the main water flow direction. Then, pressure taps are installed at the pressure tapping points outside the cofferdam, maintaining the same installation elevation. The two pressure taps are connected to the high-pressure and low-pressure ends of the differential pressure measurement unit via pressure-resistant pipelines. An air vent valve is installed at the highest point of the pressure tapping pipeline, and a drain outlet is installed at the lowest point, allowing air bubbles to be discharged through the air vent valve and sediment to be discharged through the drain outlet without entering the differential pressure measurement unit.

[0036] The internal and external pressure difference output by the differential pressure measurement unit is converted into the internal and external head difference by the control unit. The conversion relationship is as follows:

[0037]

[0038] Where: internal and external head difference : Static head difference between the two sides, subsequent access determination and control input; internal and external pressure difference The pressure difference output by the differential pressure measurement unit serves as the conversion input and reflects the hydrostatic pressure difference between the two sides; the density of water. : Density of the pressurized medium, which is the conversion factor from pressure to head and corrected for water temperature and sediment content; Gravitational acceleration. Gravitational acceleration constant;

[0039] After conversion, the internal and external head difference is written into the measurement baseline of the control unit, and the zero-point state of the differential pressure measurement unit is recorded as the baseline zero point. During use, the same-source differential pressure acquisition ensures consistent comparison benchmarks, reducing the uncertainty of dual-sensor drift superposition. Clear exhaust and sewage discharge paths make the internal and external pressure difference closer to the static pressure difference, thereby reducing transient jumps and slow drift. Internal and external head difference The conversion relationship is traceable, providing a physical explanation chain for subsequent credibility gating.

[0040] During the installation and commissioning phase, the control unit performs an elevation benchmark calibration process: when the water levels inside and outside the cofferdam reach approximately equal levels through recharge and pumping, a section of the water level on the inner side is collected. With the outer water level The stable difference between the two values ​​is calculated and written into the control unit as the water level reference difference. The calibrated water level difference is then used when calculating the head difference converted from the water level, i.e., this water level reference difference is used for... Perform bias correction.

[0041] By isolating the pressure tapping point from the main flow field through a stilling well or pressure tapping chamber, the pressure collected by the pressure tapping nozzle is mainly static pressure, and a sedimentation path is formed within the stilling well, intercepting sediment before it enters the pressure tapping pipeline. The stilling well uses a cylindrical shell fixed to the cofferdam structure, and a protective grid is installed on the outside of the shell to restrict the entry of floating objects; a sedimentation zone is formed at the bottom of the shell, and the pressure tapping nozzle is installed in a position avoiding the sedimentation zone, with a flow guide baffle installed on the outside of the pressure tapping orifice to reduce the velocity of the water entering the well and form a relatively stable water column.

[0042] The top of the stilling well has an vent that connects to a high-level vent valve, allowing air bubbles inside the well to enter the pressure tapping line. After installation, the control unit performs a short-term test on the output of the differential pressure measurement unit. Once it confirms that the external surge no longer generates high-frequency spikes, the status is marked as effective stilling water isolation. During use, the stilling well minimizes dynamic pressure intrusion, ensuring the internal and external head difference is close to the static head difference. The sedimentation zone and flow guide baffles reduce the covering of the pressure tapping orifice, minimizing measurement hysteresis and intermittent distortion. Once the venting path is determined, air bubble retention is reduced, minimizing elastic hysteresis in the pressure tapping line.

[0043] During the removal of the bridge pier foundation, stilling wells and retaining components were installed on the inner and outer sides of the cofferdam, respectively. Pressure tapping lines on both sides were connected to the same differential pressure measurement unit. The vent valve was opened and closed after continuous water discharge. At the start of dismantling, there was no surge on the outer side, the differential pressure output was stable, and the control unit was calibrated.

[0044] Several days later, as sediment increased inside the cofferdam, the differential pressure output lagged behind the pumping action. The control unit confirmed the measurement's reliability and set the "safe action only" setting to "safe action only." Personnel followed the instructions to open the flushing branch. After the sediment was discharged from the outlet, the differential pressure output resumed following the flow. The control unit then lifted the restriction and continued verification. The direct differential pressure measurement link still exhibited fine particle deposition or gradual distortion due to diaphragm temperature drift. With only a single differential pressure signal, the calculated head difference might be within acceptable limits before the dismantling process was completed, leading to boundary misjudgments. Therefore, a verification channel was needed to place the differential pressure-converted head difference and the water level-converted head difference under the same time reference. The comparison results were converted into executable gating conditions, with abnormal measurements triggering safety actions first.

[0045] A verification channel is formed by the water level measurement units inside and outside the cofferdam. The control unit uses the differential pressure measurement sampling timestamp as a reference to perform piecewise linear interpolation alignment on the two water level sequences to obtain the water level head difference at the same time. Then, the consistency deviation and response hysteresis time are incorporated into the penalty expression to obtain the consistency penalty value, which is then mapped to a measurement reliability index. When the measurement reliability index is lower than the threshold, the control unit outputs a measurement unreliable state and switches to only allowing safe actions, while simultaneously prohibiting the demolition operation permit. After the measurement reliability index recovers and remains stable, the control unit allows parameter loading in step two.

[0046] The control unit uses the sampling time of the differential pressure measurement unit as a reference, retrieves the records from the internal and external water level measurement units at two adjacent sampling times, and uses linear interpolation to obtain the data at the same time. and If the water level measurement unit reports data based on an event, the control unit needs to timestamp the data and cache the two most recent records; if the sampling interval is too large to allow interpolation, then the measurement reliability index at that moment should be used. Set to lower and enter safe-only action mode.

[0047] The inner and outer water level measuring units form an observation path distinct from the differential pressure link, providing bypass evidence when hysteresis occurs due to narrowing of the pressure tapping channel. Both water level measuring units are installed in the middle of the stilling well, measuring the water column height within the well. The control unit converts the two water level readings into a water level-converted head difference, with the following relationship:

[0048]

[0049] Where: water level converted to head difference : Water level difference conversion, used as a verification reference for differential pressure conversion results; Inner water level The water level in the inner stilling well is used for verification and to characterize the position of the water surface inside the cofferdam; the water level on the outer side... The water level in the outer stilling well is used for verification and to characterize the position of the water surface outside the cofferdam.

[0050] After conversion, time alignment is performed: the water level sequence is linearly interpolated piecewise based on the differential pressure measurement sampling timestamp to form the water level head difference at the same time.

[0051] In practice, independent observation paths provide bypass evidence, increasing the detectability of gradual distortion; time alignment mitigates spurious biases caused by sampling inconsistencies; and consistency assessment focuses more on link status. Water level conversion of head difference provides an interpretable explanation for subsequent penalty expressions. By converting deviation magnitude and response hysteresis into continuous penalty quantities and mapping them to credibility indicators, the control unit can accurately make access decisions before dismantling.

[0052] To avoid misjudgment caused by surge spikes, the penalty expression adopts a continuous function with limited amplification of large deviations and still distinguishable small deviations. The control unit uses a feasible criterion to extract the response hysteresis time: using the timestamp of a change in pump speed or reinjection valve position as the starting point, the internal and external head difference is calculated. The three-point difference is calculated and its sign is taken. When the difference sign is consistent within the sliding time window and the amplitude is greater than the micro-motion threshold estimated from the fluctuation in the still water well, it can be determined that a stable monotonic trend has occurred. The difference from the starting point to this moment is the response hysteresis time. The lag penalty term has an engineering basis that allows for repeated implementation.

[0053] The control unit calculates the consistency penalty value using the following expression:

[0054]

[0055] Where: Consistency penalty value The combined penalty for deviation and lag, with a value of [value missing]. to Permissible head difference Consistency deviation scale, representing deviation from normalization and reflecting engineering tolerance; response hysteresis time. The difference in water head between the inside and outside after a step jump. The time required for a stable monotonic trend to form is a dynamic hysteresis characteristic caused by blockage and bubble retention; the allowable hysteresis time. Hysteresis scale, which is a hysteresis normalization and reflects the dynamic requirements of the demolition stage; weighting coefficient : Hysteresis penalty weight, value to Its function is to adjust the intensity of the hysteresis effect on gating; internal and external head difference Water level conversion head difference The value range is the same as before, and it is the input for penalty calculation.

[0056] The control unit maintains the bypass trigger index while keeping the pump and recharge valve assembly unchanged. During the period when the system is not in a triggered state, the difference between internal and external water head is calculated. The maximum fluctuation amplitude within this segment is taken as the static steady-state noise band; when the three-point differential amplitude continuously exceeds this noise band and maintains a consistent sign, a trend is determined to have emerged, thus obtaining... .

[0057] The log-hyperbolic cosine function exhibits approximately quadratic growth with small deviations and approximately linear growth with large deviations, thus it can distinguish sustained small deviations and suppress short-term spikes. The control unit maps the consistency penalty value to a measurement reliability index, with the following mapping relationship:

[0058]

[0059] Where: Measurement reliability index : Reliability metric, with a value range of 0 to Its function is to input the admission criteria for steps two and three and drive the switching of safety actions; attenuation coefficient Attenuation coefficient, range of values to Adjust the consistency penalty value For measurement reliability indicators Sensitivity; consistency penalty value The range of values ​​is the same as before, and it is an exponential mapping input that forms a monotonic gating relationship.

[0060] The flush trigger criterion is limited to satisfying at least one of the following: consistency penalty value. Continuously exceeding a preset threshold for a certain period of time; response lag time Continuous exceedance of hysteresis tolerance time After a step change in the setpoint of the pumping or recharge valve assembly, No identifiable monotonic trend was observed.

[0061] The control unit first puts the pumping pump and the recharge valve group into a safe state, then opens the flushing branch valve, opens the sewage outlet, closes the flushing branch after flushing is completed and performs air venting, and finally re-establishes the zero-point baseline or refreshes the water level reference difference.

[0062] After outputting the measurement reliability index, gating is performed: when the measurement reliability index is lower than the threshold, the control unit outputs the measurement unreliable state and switches to only allowing safe actions, while prohibiting the dismantling work permit; after the measurement reliability index recovers and remains stable, the control unit allows the process to proceed to step two.

[0063] In practice, the penalty expression incorporates deviation and hysteresis into the same continuous quantity, making the gating insensitive to short-term disturbances but sensitive to persistent distortion; reliability metrics are measured. As an explicit output, it is fixed and can be directly called upon in subsequent steps to form a unified admission basis;

[0064] Step 2: Measure the reliability index Under the premise of meeting the requirements, first set the allowable range of internal and external head difference and the upper limit of the rate of change of head difference according to the current demolition stage, and then construct the internal and external head difference. and the rate of change of head difference Joint control commands for feedback quantities The exchange of water inside and outside the cofferdam is driven by adjusting the speed of the pumping pump and the opening of the recharge valve group.

[0065] Based on this, further consideration is given to the degree of head difference exceeding the limit, the degree of head difference change rate exceeding the limit, and the measurement reliability index. The degree of decline is comprehensively calculated as a bypass trigger indicator. Bypass trigger indicators The fault-tolerant bypass valve ensures that the control system prioritizes the execution of the pressure equalization safety action even in the event of failure or severe boundary deterioration.

[0066] During the cofferdam removal project, the difference in water head between the inside and outside... It is closely related to the internal force distribution and seepage state of the cofferdam structure. During different stages of removing the internal supports, walers, and retaining components, the overall stiffness and stress path of the cofferdam change, affecting the same internal and external head difference. The corresponding levels of risk are not the same; at the same time, the rate of change of head difference If the difference is too large in a short period of time, even if the instantaneous head difference is still within the range, it may induce local instability due to increased seepage and sudden changes in the effective stress of the soil.

[0067] Using only the static value of the head difference at a single moment as the basis for judgment cannot cover the dynamic risks during the demolition process. Therefore, it is necessary to introduce two constraints into the control logic: a safety window for the head difference and an upper limit on the rate of change of the head difference, and to construct a joint control instruction that can take into account both constraints. This allows the head difference to be continuously guided to move slowly along the safe zone throughout the entire operation of the pumping and recharge valve assembly.

[0068] Based on the internal and external head difference and measurement reliability index obtained in step one, the control unit calculates the deviation relative to the reference value from the calculated lower limit, upper limit, and upper limit of the head difference change rate at the current stage, according to the dismantling stage identifier. Then, the rate of change of the head difference is used to constrain the pumping speed, finally obtaining a joint control command for the pumping pump and reinjection valve group. The control unit continuously monitors the measurement reliability index, and when the measurement reliability index... When the value is not lower than the set value, the joint control command is executed. Only then can it be issued; when the measurement confidence index drops to the measurement confidence index When the lower limit is reached, joint control commands are executed. Execution is halted. The acceptable range and expected operating point of the internal and external head difference of the cofferdam vary during the dismantling phase, and the internal and external head difference are acceptable ranges and expected operating points at different dismantling phases.

[0069] By combining the stage reference head difference and the head difference safety window, the control unit establishes a safety boundary based on clearly defined dimensions. For the current demolition stage, the control unit reads the allowable lower limit of the head difference from the parameter table. and the upper limit of head difference And calculate the intermediate reference head difference for this stage. To avoid frequent and large-scale pumping operations caused by sudden changes in reference values, the reference value is not directly taken as the midpoint. Instead, a segmented smooth reference trajectory is formed by combining the operational intentions within each stage (such as gradually reducing the head difference or maintaining approximate balance). During the removal of internal supports, the reference trajectory may be biased towards the small head difference range, while in the preparation stage before the partial removal of retaining components, the reference trajectory is closer to the center of the safe range given by the structural analysis.

[0070] The following formula can be used to calculate the reference head difference:

[0071]

[0072] Where: reference head difference The target value of the head difference to be maintained in the current stage, which is taken as the lower limit of the allowable head difference. Maximum allowable head difference between;

[0073] Lower limit of permissible head difference The minimum allowable value for the difference between internal and external water head, determined by structural analysis and construction experience during the current demolition phase, is taken from the range of values ​​determined by the engineering design and is generally not less than the negative boundary.

[0074] Maximum allowable head difference The maximum allowable value of the internal and external water head difference determined by the structural analysis at the current demolition stage. The range of values ​​is set according to the bearing capacity of the cofferdam structure and the seepage safety conditions.

[0075] proportionality coefficient : Offset coefficient within the stage, range of values to ;when Values ​​close to At that time, reference head difference Closer to the lower limit of allowable head difference ,when Values ​​close to At that time, reference head difference Closer to the upper limit of the allowable head difference ;

[0076] The control unit updates the lower limit of the head difference allowable during the dismantling phase switching. Maximum allowable head difference and proportionality coefficient And adjust the reference head difference through a smooth transition. This avoids excessively large reference jumps during phase transitions.

[0077] By introducing a lower limit for permissible head difference Maximum allowable head difference and reference head difference The control unit obtains a clear head difference safety boundary and target position, enabling subsequent control commands to... It can organize drainage and recharge operations within the permitted intervals of the structure. (Proportionality coefficient) The introduction of this feature allows different demolition stages to naturally favor a more conservative or more aggressive head difference range through parameter adjustments, adapting to various engineering scenarios without modifying the control algorithm structure. (Reference head difference) This provides a continuous target for subsequent head difference deviation calculations, reduces the drastic movements of pumping and recharge valve groups during phase switching, and is beneficial for the stable operation of the control system.

[0078] Safety window for head difference and reference head difference Once determined, the rate of change of head difference is introduced. The control commands simultaneously constrain both the head difference deviation and the rate of change of the head difference, thereby suppressing excessively rapid pumping or reinjection caused by chasing the reference value. The control unit uses the current internal and external head difference... head difference with reference The difference is used as the head difference deviation input, and the rate of change of the internal and external head difference at adjacent time points is used as the head difference change rate. A smoothing saturation function is used to compress the deviation and rate of change, and the compression results are linearly superimposed into joint control commands. .

[0079] The data is obtained as discrete difference, and noise reduction processing is provided: the control unit acquires data at a fixed sampling period. The rate of change of head difference is calculated by dividing the difference between adjacent samples by the sampling time interval. To suppress surge noise, the control unit applies a moving average or a first-order inertial filter to the difference results before outputting the result. .

[0080] Joint Control Command The direction and magnitude of the adjustment corresponding to the pump speed and the opening degree of the recharge valve group can be converted into specific execution commands through table lookup or linear mapping in practical applications.

[0081] Joint control commands can take the following forms:

[0082]

[0083] Where: Joint control command The control unit outputs normalized control commands to the pumping and recharge valve assembly, with values ​​of... 1 to Positive values ​​can correspond to enhanced drainage or weakened reinjection, while negative values ​​can correspond to weakened drainage or enhanced reinjection; time variable : Continuous time variable, with values ​​ranging from the construction period during the demolition phase; head difference deviation : The instantaneous deviation of the current internal and external head difference relative to the reference head difference; the range of values ​​is determined based on the allowable range of head difference; the rate of change of head difference. The rate of change of the internal and external head difference at adjacent time points can be approximated using discrete-time difference, and its value range is set based on engineering experience; head difference gain coefficient. : Head difference deviation channel gain, which is positive; rate of change gain coefficient : Rate of change of head difference channel gain, which is positive; Head difference compressibility coefficient : Compressibility factor acting on head difference deviation, positive value; rate of change compressibility factor : The compressibility coefficient acting on the rate of change of head difference, a positive value;

[0084] The control unit, according to the joint control command The sign and magnitude of the value are used to generate the setpoints for the pumping speed and the opening degree of the reinjection valve assembly, for example, by using linear mapping or piecewise mapping. The sign corresponds to the direction of pumping or reinjection, and the amplitude corresponds to the magnitude of the actuator's action. After the actual response of the pumping and reinjection valve assembly, the internal and external head difference... and rate of change of head difference This is then updated to form a closed-loop control system.

[0085] when When it is positive, the control unit will Mapped to the increment of the pump speed setpoint, the reinjection valve assembly remains at a safe minimum opening or closed; when When it is negative, the control unit will Mapped to the increment of the reinjection valve assembly opening setpoint, the pumping speed drops to a safe speed or stops; when the bypass trigger indicator... When entering the triggering zone, the control unit prioritizes the connection of the equalizing bypass channel and puts the pumping pump and the reinjection valve group into a safe state.

[0086] Linear mapping or lookup table mapping; the lookup table is written to the control unit during the debugging phase, and the table entries are... A one-to-one correspondence between the set values ​​of the pumping speed and the set values ​​of the recharge valve assembly opening.

[0087] When in use, it is controlled by joint control commands. By taking both the head difference deviation and the rate of change of head difference into account, the pumping and reinjection behaviors not only track the reference head difference. Moreover, it automatically suppresses excessively rapid changes, reducing the risk of severe head difference fluctuations caused by catch-up deviations.

[0088] The following case illustrates the construction of a bridge pier across a river. The cofferdam was a steel sheet pile retaining structure. The internal supports were removed in two stages, followed by the removal of some retaining components. Before removing the second layer of internal supports, the project team determined the lower limit of the allowable head difference for the second stage. Set the safety deviation to near zero, and set the upper limit of the allowable head difference. Set it to a conservative value less than the design limit, and then use a proportional coefficient. Reference head difference The system was set to maintain a near-equal water level both inside and outside the water. The control unit began operating according to the joint control commands the night before dismantling. By adjusting the speed of the pumping pump and the opening of the recharge valve, the water level inside the cofferdam gradually approaches the water level outside, and the rate of change of the head difference... Maintaining near the set upper limit, the head difference curve on the control screen gradually enters the safe window and changes slowly. After removing the second inner support, the on-site personnel found that the displacement of the deformation monitoring point of the inner wall of the cofferdam changed smoothly without any sudden changes. The support removal was successful, providing stable hydraulic boundary conditions for the subsequent removal of the retaining components.

[0089] Even in joint control directives Even after taking into account both head difference deviation and head difference change rate, issues still exist such as control unit power failure, actuator jamming, and measurement reliability indicators. Sudden drops or communication link interruptions, etc.

[0090] If the aforementioned failure occurs, relying solely on the pumping and reinjection valve assembly to restore normal operation may cause the internal and external head difference to remain unfavorable for an extended period, potentially even accumulating into a dangerous range. Therefore, it is necessary to establish an independent pressure equalization bypass channel outside the main pumping and reinjection circuit. This channel should construct a physical safety net, a slow pressure equalization path, using flow-limiting elements and a fault-default safety valve, and be triggered by a bypass indicator. This drives the opening of the channel, so that when the control system fails or extreme deviations occur, the head difference will actively fall back to the safe range through the bypass channel, instead of relying on manual intervention or waiting for the main control to recover.

[0091] The measurement reliability index in step one The internal and external head difference in the sub-step preceding step two. Rate of change of head difference and the upper limit of the head difference Upper limit of the rate of change of head difference As input, three dimensionless safety deviations are constructed: the degree of exceedance of head difference limits, the degree of exceedance of safety change rate limits, and the degree of decrease in measurement reliability. These three deviations are then linearly combined and mapped to a bypass trigger index through a smoothing trigger function. .

[0092] When bypass triggers the indicator When the preset threshold is exceeded, the equalizing bypass channel is activated, opening from the fault default safety valve to the preset current limiting opening; when the bypass trigger indicator... After the water level drops below the threshold and remains stable for a period of time, the bypass channel can be gradually closed or kept at a small opening according to a predetermined strategy to avoid frequent opening and closing. In actual engineering, the equalization bypass channel can form a pipeline spanning the water bodies inside and outside the cofferdam. A throttling orifice plate or a constant flow valve is installed in the pipeline, connected in series with a spring-reset electric valve. When the electrical signal fails, the spring drives the electric valve back to a safe opening, thus ensuring the safety attribute of equalization in case of failure. This addresses the difference in head between the inside and outside water. The extent of exceeding the limit and the rate of change of head difference Exceeding limits and measurement reliability indicators The degree of decline is uniformly mapped to a bypass trigger indicator. This means that the opening of the equalizing bypass channel no longer depends solely on a single condition, but rather comprehensively considers boundary deviations and measurement reliability. The changes in the setpoints for the pump speed and the opening of the reinjection valve assembly within adjacent control cycles must not exceed a preset upper limit; this upper limit can be determined by… It can be obtained indirectly or given during the debugging phase.

[0093] Therefore, the control unit first constructs three dimensionless deviations: the first is the deviation of the head difference exceeding the limit. Used to characterize the current internal and external head difference Upper limit of relative head difference The degree of excess; secondly, the deviation of the rate of change from the limit. Used to characterize the rate of change of the current head difference Upper limit of the rate of change of relative head difference The degree of excess; third, the deviation in credibility. Used to characterize measurement reliability indicators The degree of inadequacy of the relative credibility threshold. The aforementioned deviations can be normalized to a finite interval using a piecewise linear function or a piecewise proportional function, while maintaining monotonicity.

[0094] Subsequently, the control unit uses a smooth triggering formula to generate bypass triggering indicators:

[0095]

[0096] Where: Bypass trigger indicator : An indicator for controlling the opening degree of the equalizing bypass channel, with a value range arrive ;when near When it can be considered that bypass is not triggered, when near This can be considered as a complete triggering of the bypass;

[0097] Deviation of head difference beyond the limit Current internal and external water head difference relative to the upper limit of the head difference The dimensionless deviation can be set to a range of values. arrive ;when When not close to the upper limit near ,when When the limit is exceeded As the degree of excess increases;

[0098] Deviation of rate of change beyond limit Current rate of change of head difference Relative to the upper limit of the rate of change of head difference The dimensionless deviation can be set to a range of 0 to... When the rate of change is below the upper limit near When the rate of change exceeds the upper limit As the degree of excess increases;

[0099] Decrease in credibility deviation : Measurement reliability index The value range for the dimensionless insufficient quantity relative to the credibility threshold can be set as follows: arrive When measuring reliability indicators When above the threshold near When measuring credibility index When below the threshold As the degree of insufficiency increases;

[0100] Weighting coefficient , , : These correspond to the deviation of the head difference exceeding the limit. Deviation of rate of change beyond limit and the deviation from the decrease in credibility The weights are all positive values.

[0101] :when Time to take ;when Time to take Exceeding The relative quantity (available) or (Return to One) :when Time to take ;when When taking the relative amount of the excess (in terms of...) (Return to One) :when Time to take ;when The relative amount of the threshold difference (in time) Returning to One).

[0102] The above relationship is essentially a weighted sum of three deviations, compressed to the 0-1 range by a smoothing mapping function. When the degree of head difference exceeding the limit, the degree of head difference change rate exceeding the limit, and the degree of measurement reliability decrease all increase simultaneously, the bypass trigger index... Approaching The control unit can select a bypass trigger threshold value, for example... ,when When the value exceeds the threshold and remains above it for a certain period of time, the equalizing bypass valve is driven to open.

[0103] Bypass trigger indicator By integrating risks from three different sources into a single continuous indicator, the decision to activate the equalization bypass channel no longer depends on a single over-limit condition. This enables timely triggering of equalization behavior even in scenarios where the head difference over-limit is not significant but the measurement reliability is severely reduced.

[0104] Through weighting coefficients , , Adjustments can increase the deviation of head difference from the limit in seepage-sensitive engineering projects. The weighting of the deviation from the limit is increased in sensitive engineering projects for equipment protection to improve the rate of change. The weighting of the measurement environment in complex engineering projects improves reliability and reduces deviation. The weighting of the solution enhances its adaptability.

[0105] Bypass trigger indicator Compared with the measurement reliability index in step one Maximum allowable head difference and the upper limit of the rate of change of head difference This forms a parameter chain, making it easier for the subsequent step three to directly use its status to determine the demolition operation permit.

[0106] In bypass trigger indicators After establishment, a physical channel needs to be constructed that can reliably perform pressure equalization behavior even in the event of control unit failure or power outage. A pressure equalization bypass channel is constructed by connecting a flow-limiting element in series with a fault-default safety valve. This ensures that the flow rate in this channel will not cause excessively rapid changes in head difference after opening, and that it automatically returns to a preset safe opening degree in the event of power failure. Specifically, a bypass pipeline is arranged between the inside and outside of the cofferdam. A throttling orifice plate or a fixed-opening flow-limiting valve is installed in the bypass pipeline. The orifice diameter or opening degree of the flow-limiting element is calculated by the designer based on the desired pressure equalization time and the volume of water in the cofferdam. A spring-reset electric valve is connected in series downstream of the flow-limiting element. This electric valve can switch between a closed state and a fully open state when driven by an electrical signal. When there is no electrical signal, the spring pushes the valve to a preset safe opening degree, such as maintaining partial opening rather than complete closure.

[0107] The selection of flow-limiting components should ensure that the rate of change of head difference generated by the equalizing flow rate under the condition of maximum possible head difference does not exceed the upper limit of the rate of change of head difference. It can be achieved by using an orifice plate, a constant flow valve, or a small-diameter bypass pipe, and can be achieved by changing the orifice plate diameter or adjusting the constant flow valve value.

[0108] The control unit is based on the bypass trigger indicator With threshold value Adjust the electric valve control signal according to the relationship. When the value is below the threshold and the situation is stable, the electric valve closes or opens slightly. When the water level exceeds the threshold and remains above it for an extended period, the control unit sends an opening command, causing the electric valve to open fully, creating a controlled pressure equalization flow with the flow-limiting element; when the head difference between the inside and outside of the cofferdam... When the water head difference changes back into the safe range, the rate of change is... Falling back to the upper limit of the rate of change of head difference Once the reliability index is restored, the electric valve will return to a partially open, safe opening according to the engineering strategy to cope with the next sudden deviation. When the control unit loses power, the electric valve does not receive electrical signals. The spring mechanism pushes the electric valve to a safe opening. The flow-limiting element and the electric valve form a pressure equalization channel with a fixed flow rate. The electric valve will not lose its pressure equalization capability due to the failure of the main control system.

[0109] For example, during the dismantling of a river cofferdam, the water level outside the reservoir increased rapidly due to temporary flood discharge from the upstream reservoir. Within a short period of time, the difference in water head between the inside and outside the reservoir approached the difference in water head between the inside and outside reservoirs. Allowable upper limit rate of change of head difference Approaching the upper limit of the rate of change of head difference Insufficient rinsing leads to low measurement reliability indicators and bypass trigger indicators. Rapidly approaching 1. The control unit determines that the bypass is open and pushes the electric valve to open. The water inside and outside slowly equalizes the pressure through the flow limiting element. On-site detection shows that the water level difference between the inside and outside of the cofferdam has decreased, and the strain and displacement curves of the inner wall of the cofferdam are within a stable range. In the event of a sudden power outage at the construction site, the electric valve is reset to a safe opening by the spring after losing power. The pressure equalization bypass channel maintains limited flow pressure equalization to prevent the water head difference between the inside and outside of the cofferdam from falling into an uncontrollable state as the external water level changes.

[0110] When in use, the series connection between the flow limiting element and the fault default safety valve ensures that the pressure equalization bypass channel will not introduce excessively rapid changes in head difference after it is opened. This avoids the head difference from remaining at a high level for a long time when the pumping and reinjection main circuit fails, and also avoids the pressure equalization process from causing new instability due to being too fast.

[0111] The selection of spring-reset electric valves ensures that the pressure equalization bypass channel automatically enters a preset safe opening state in the event of power outage or control unit failure, achieving the design goal of fault-based safety. Through the arrangement of bypass pipelines, flow-limiting elements, and electric valves, a physical pressure equalization path independent of the pumping and reinjection valve groups is formed. This allows the entire automated cofferdam removal system to still rely on the bypass channel to equalize the internal and external water head difference even in the event of a single point of failure. Gradually pull back to a safe range to buy time for subsequent restoration of control or manual takeover.

[0112] Step 3: Adjust the internal and external head difference Boundary constraints and measurement reliability indicators The availability constraints are uniformly written into the demolition operation permit determination chain, and then the permit determination is implemented to the enabling circuit of the vibration demolition equipment, crane winch and underwater cutting power source through dual-channel hardware interlocking. When the permit is revoked, the degradation and record are performed in a fixed order.

[0113] Cofferdam dismantling often involves the simultaneous removal of supports, removal of components, and hoisting and recovery of equipment while the pumping and reinjection valve assemblies are continuously operating. If the dismantling equipment is started and stopped solely based on personnel observation of water levels or interface indicators, the permissible boundaries are easily affected by fluctuations in external water levels and transient changes in pumping and reinjection. Furthermore, when measuring reliability indicators... When the head difference between the inside and outside decreases, It is still possible to mask pressure tapping delays within permissible limits, thereby initiating dismantling operations under unfavorable boundaries. To ensure consistency of permissible boundaries across different shifts and different equipment, the dismantling process needs to be divided into auditable stages, and the boundary parameters and permissible decision sequence for each stage need to be fixed within the control unit.

[0114] After receiving the dismantling stage identifier, the control unit calls the lower limit of the head difference allowed for that stage. Maximum allowable head difference Upper limit of the rate of change of head difference And freeze a boundary snapshot at the moment of phase switch; then the control unit measures the confidence index. As a pre-gating control, the internal and external head difference is determined only after the gate passes. Whether the water head difference falls within the closed interval formed by the lower and upper limits of the allowable head difference, and determine the rate of change of the head difference. Is it subject to the upper limit of the rate of change of head difference? Constraints; after the boundary conditions are met, the control unit then reads the bypass trigger indicator. If the bypass triggers the indicator, the state is as follows. If the equalizing bypass channel is connected, the system will directly output a prohibition on work. Based on this, the control unit will output the demolition work permit status (permitted or prohibited) and write the stage identifier, boundary snapshot, and trigger reason into the log entry.

[0115] Convert the current type of demolition action into a stage identifier that can be called by the control unit, and link the stage identifier with the allowable lower limit of head difference. Maximum allowable head difference Upper limit of the rate of change of head difference The boundary is bound to a stage boundary triplet. The stage identifier can be selected by the operator on the console or entered via the preparation contact for dismantling the equipment. However, upon receiving the stage identifier, the control unit performs the same action: first, it writes the stage identifier to the stage field of the record entry; then, it writes the stage boundary triplet to the boundary field of the record entry; finally, it freezes the boundary snapshot and locks it as the input source for the current stage's permission determination. The frozen boundary snapshot does not change with short-term parameter fluctuations, but is only updated during stage switching, thus avoiding inconsistencies in permission standards caused by temporary boundary modifications by the work team within the same stage. Specifically, the control unit generates a boundary snapshot each time a stage switch is triggered, and writes the boundary snapshot and stage identifier together into the record entry, while simultaneously using the boundary snapshot as a fixed input for the next cycle's permission determination.

[0116] When in use, after the stage boundary triplet is bound, the boundary parameters referenced in the permission determination have a unique source, reducing disagreements among different personnel regarding the boundary caliber. After the boundary snapshot is fixed, any permission issuance or revocation can be traced back to the lower limit, upper limit, and upper limit of the head difference allowable limit at that time, facilitating the restoration of boundary conditions during review.

[0117] Measuring credibility indicators Difference between internal and external water head Rate of change of head difference Bypass trigger indicator The organization uses a fixed-order decision chain, ensuring a single causal link between license issuance and revocation. The control unit first determines the reliability index. If the gate control status is not met, operation is directly prohibited and only safe actions are allowed; if the gate control is met, the difference in internal and external head is then determined. Whether it is between the lower and upper limits of the allowable head difference, and at the same time determine the rate of change of the head difference. Is it subject to the upper limit of the rate of change of head difference? Constraints; after both are satisfied, then examine the bypass trigger indicator. If the bypass triggers the indicator If the equalizing bypass channel is in the control state, operation is prohibited.

[0118] To avoid repeated permitting due to transient fluctuations caused by surges or pump start-stop, the control unit separates the entry conditions from the holding conditions: the entry condition requires a difference in internal and external water head. rate of change of head difference Permissions can only be issued after continuous stability within the boundary; minor transgressions that are permitted for very short periods should be recorded as a warning, but persistent transgressions or bypasses should not trigger indicators. When entering the trigger zone, permission must be revoked and the system must be downgraded.

[0119] Among them, the control unit is based on the measurement reliability index →Difference between internal and external water head → Rate of change of head difference → Bypass Trigger Indicator The conditions are determined sequentially, and the entry conditions are bound to the license issuance, while the retention conditions are bound to the license retention.

[0120] When in use, a fixed decision sequence makes permission changes have an interpretable trigger chain, reducing permission jitter caused by concurrent conditions; entering a hold-and-separate state allows short-term fluctuations to be included in the prompt log instead of an immediate shutdown command, while not relaxing the revocation conditions for continuous out-of-bounds.

[0121] Bypass trigger indicator Incorporating it into the end of the judgment chain ensures that the permitted layer is simultaneously switched to prohibited when the equalization bypass channel is taken over, preventing the equipment from remaining enabled during the equalization process.

[0122] If a dismantling operation permit remains only at the interface prompt or communication command level, it may still fail to constrain the dismantling equipment's actions due to communication interruptions, loose wiring, or operator error. Dismantling equipment possesses mechanical inertia during vibration removal, lifting, or cutting; if the permit revocation cannot be achieved by hardware-based disconnection of the enabling circuit, equipment operation may continue under unfavorable head difference boundaries.

[0123] Meanwhile, the cofferdam site is damp and muddy, and power fluctuations and insulation degradation may cause single-path interlocking to fail. Therefore, dual-channel hardware interlocking is required, and feedback consistency verification should be introduced to keep the interlocking consistent with the equipment status. When the permission is revoked, the pumping pump, the reinjection valve group and the equalizing bypass channel must enter the safe state in a fixed sequence, and the trigger source and key parameters should be solidified to support reset and handover.

[0124] After receiving the demolition operation permit status, the control unit maps it to two independent interlock on / off combinations and connects the two interlocks in series to the demolition equipment enable circuit. Disconnecting either interlock deactivates the device. Simultaneously, the control unit reads the auxiliary contacts of the demolition equipment contactor or the hydraulic station's permission contacts as equipment feedback and performs a consistency check between the interlock expectation and the equipment feedback. If they do not match, the permit is immediately revoked. After revoking the permit, the control unit performs a degradation process in a fixed sequence: first, it disconnects the interlocks; then, it issues a command to the pump to decelerate to a stop or maintain a safe speed; it issues a command to the reinjection valve group to close or maintain a safe opening; and finally, it executes a degradation process based on the bypass trigger indicators. Maintain the flow-limiting opening of the equalizing bypass channel to ensure the difference in head between the inside and outside. The water level is expected to fall back within the permitted range; during the downgrade process, phase markers, boundary snapshots, and internal and external head differences will be used. Rate of change of head difference Measurement reliability index Bypass trigger indicators Write the feedback status to the record entry.

[0125] A safety relay or safety controller serves as the interlocking actuator, outputting two hard-contact points that are physically isolated. These two hard-contact points are connected in series to the enable circuit of the vibration extraction equipment, crane winch, or underwater cutting power source, thus achieving default disabling at the circuit level. When permission is granted, the control unit energizes the safety relay coil, closing the two hard-contact points and providing the enable circuit with a power or hydraulic station permission signal. When permission is revoked, the coil de-energizes, and the two hard-contact points return to the open state. To prevent single-point failure due to contact adhesion, the safety relay uses two sets of independent contacts, and the two hard-contact points are connected to different terminal blocks. Insulating isolation components are installed between the terminal blocks to prevent short circuits caused by moisture.

[0126] Regarding feedback consistency verification, the control unit draws feedback from the equipment side via the contactor auxiliary contact or the hydraulic station pressure establishment contact, and compares it with the expected interlock state: when the expected interlock is open but the equipment feedback still shows energized, the control unit determines a discrepancy and immediately executes the revocation of permission and demotion sequence. In an equivalent implementation, the interlock execution component can be a dual-channel safety relay, a dual-channel safety controller, or two independent contactors connected in series; the equipment feedback can be a contactor auxiliary contact, a frequency converter running contact, or a hydraulic station solenoid valve feedback contact, but it must satisfy the terms "interlock can be disconnected and enable" and "feedback can reflect actual enable". The control unit sets a feedback determination delay after the interlock state changes. Allowing for a physical delay in contactor engagement / disengagement; if in If the feedback is still inconsistent, it is determined that the contacts are stuck or the wiring is abnormal, and the permission is revoked and the device is downgraded.

[0127] The control unit powers the safety relay by granting the removal work permit and switches to the enable circuit via two series hard contacts. At the same time, it checks the equipment feedback contacts against the expected interlock status. If any discrepancy is found, it proceeds to revoke the permit and downgrade the system.

[0128] In use, the dual-channel series hard contacts ensure that disconnection of any channel will deactivate the device, forming a hardware constraint that disables the device by default when power is lost, thus reducing the risk of single-point failure. The feedback consistency check extends the interlock constraint from the signal layer to the action layer, reducing the situation where the interlock has been revoked but the device is still operating without being recognized.

[0129] The regulations specify the sequence of actions following the revocation of permission, ensuring that the head difference boundary and the equipment action boundary converge synchronously. The control unit uses interlock disconnection as its first action, first cutting off the enable circuit to stop the dismantling equipment; then it issues commands to the pumping pump to decelerate to a stop or maintain a safe speed, and issues commands to the reinjection valve group to close or maintain a safe opening, preventing pumping or reinjection from continuing to increase the internal and external head difference. Move away from the permitted range; then, based on the bypass trigger indicator. Maintaining or opening the flow-limiting opening of the equalizing bypass channel to maintain the internal and external head difference Lower limit of head difference allowed Maximum allowable head difference The flow will then reverse; finally, it will trigger the source identifier, stage identifier, boundary snapshot, and internal / external head difference. Rate of change of head difference Measurement reliability index Bypass trigger indicators The pump status and feedback status are written to the same record entry, and the curve segments before and after the permission change are fixed to the storage medium.

[0130] As an example: In the removal of retaining structure components, the enabling circuit of the vibration removal equipment is connected in series to a safety relay via two hard contacts. After the operator requests to enter the removal phase, the control unit determines the activation based on the measured reliability index. Difference between internal and external water head rate of change of head difference Permit issued, vibration removal equipment begins to vibrate and maintains clamping; water from the outside causes a head difference between the inside and outside. The head difference continues to approach the upper limit of the allowable range. And the rate of change of head difference Exceeding the upper limit of the rate of change of head difference The control unit revoked the permit according to the holding conditions, the safety relay was de-energized, and the vibration removal equipment stopped vibrating; the control unit then decelerated and stopped the pumping pump and opened the equalizing bypass channel to the flow-limiting opening, the water levels inside and outside the cofferdam gradually converged, and the permit remained in the prohibition state until the difference in water head between the inside and outside was reached. Return to the permitted range and measure the confidence index Once the situation stabilizes, the license will be reissued. In an equivalent implementation, curve segment solidification can be replaced by key point sequence solidification, and pump deceleration and stopping can be replaced by maintaining a safe speed. However, the order of first disconnecting the interlock, then adjusting the pumping and recharge, then connecting the pressure equalization pipe, and finally solidifying and recording must remain unchanged.

[0131] The control unit is executed in the following sequence: interlock disconnection → pumping and recharge valve assembly enters safe mode → pressure equalization bypass channel flow restriction connection → record entries are solidified, and the internal and external head difference is recorded. Rate of change of head difference Measurement reliability index Bypass trigger indicator Write the boundary snapshot along with the record entry.

[0132] In use, a fixed degradation sequence ensures that permission revocation and hydraulic boundary adjustment are synchronized, reducing the risk of continued deterioration of head difference due to equipment downtime. The equalization bypass channel acts as a takeover point during degradation, providing a clear physical path to guide the internal and external head difference even when the boundary deteriorates or control fails. It has fallen back to the permissible range.

[0133] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0134] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0135] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0136] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0137] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An automated dismantling system for cofferdam construction, characterized in that: include, Pressure tapping points are set inside and outside the cofferdam, and the pressure tapping pipelines are connected to the same differential pressure measurement unit. The control unit converts the internal and external pressure difference into the internal and external water head difference. The pressure tapping points are equipped with static wells or pressure tapping chambers and controllable flushing branches, and the internal and external water levels are collected for consistency verification to form a measurement reliability judgment. When the measurement reliability judgment is met, the control unit loads the range of internal and external head difference and the upper limit of the rate of change of head difference, and uses the internal and external head difference as feedback to adjust the speed of the pumping pump and the opening of the recharge valve group. A controlled pressure equalization bypass channel is set up. When the head difference or rate of change exceeds the limit, the measurement is unreliable, or the control unit fails, the controlled pressure equalization bypass channel will limit the flow and equalize the pressure. The dismantling process is divided into stages, binding the range of internal and external head difference and the upper limit of the rate of change of head difference; the control unit determines the dismantling operation permit based on the measurement reliability, the internal and external head difference and the rate of change of head difference, and the dual-channel hardware interlock is connected to the dismantling equipment enable circuit, and the permit is revoked and downgraded.

2. The automated dismantling system for cofferdam construction according to claim 1, characterized in that: The still water well or pressure tapping chamber is fixed to the cofferdam component, with a protective grid on the outside and a sedimentation zone formed inside. The pressure tapping point is equipped with a pressure tapping nozzle, and the inlet face is perpendicular to the main flow direction and arranged in a position that avoids the sedimentation zone. The pressure tapping pipeline is equipped with an exhaust port and a sewage outlet, and is connected to an exhaust valve and a sewage outlet respectively. An exhaust chamber is formed at the top of the still water well and is connected to the exhaust port.

3. The automated dismantling system for cofferdam construction according to claim 2, characterized in that: The controllable flushing branch and the pressure tapping pipeline are connected in parallel and include a flushing valve and a drain valve. When the predetermined cycle is reached, the control unit first puts the pump and the recharge valve group into a safe state, then opens the flushing valve and the drain valve to complete the backwashing. After the backwashing is completed, the exhaust valve is opened briefly to vent and the pressure tapping is restored.

4. The automated dismantling system for cofferdam construction according to claim 3, characterized in that: When the differential pressure-converted head difference and the water level-converted head difference continue to deviate and the head difference response is delayed after pumping and recharge, the control unit determines that the measurement reliability judgment is not met, triggers backwashing of the controllable flushing branch, and re-executes consistency verification and writes it into the flushing self-test record after the backwashing is completed.

5. An automated dismantling system for cofferdam construction according to claim 4, characterized in that: The internal and external water level measurement units output water level records with timestamps. The control unit caches the water level records and uses the sampling time of the differential pressure measurement unit as a reference. After performing piecewise linear interpolation and alignment on the internal and external water levels, the water level difference is converted into a head difference, and a measurement reliability judgment is formed accordingly.

6. An automated dismantling system for cofferdam construction according to claim 5, characterized in that: After loading the internal and external head difference range, the control unit generates a reference head difference and combines the deviation of the internal and external head difference with the rate of change of the head difference to form a joint control command. The joint control command is mapped to the set value of the pumping speed and the set value of the recharge valve group opening, respectively, and the rate of change of the set value is limited.

7. An automated dismantling system for cofferdam construction according to claim 6, characterized in that: The controlled equalization bypass channel includes a bypass pipeline, a flow limiting element, and a fault default safety valve. The flow limiting element and the fault default safety valve are arranged in series on the bypass pipeline. When the control unit loses power, the fault default safety valve returns to the preset safety opening. The preset safety opening is the flow limiting opening and keeps the bypass pipeline connected with flow limiting.

8. An automated dismantling system for cofferdam construction according to claim 7, characterized in that: The control unit determines the degree of non-compliance based on the degree of internal and external head difference exceeding the limit, the degree of head difference change rate exceeding the limit, and the measurement reliability, and sets the bypass opening threshold, bypass closing threshold, and bypass confirmation time. When the bypass trigger indicator meets the opening conditions, it drives the fault default safety valve to open to the flow-limiting opening degree. When the closing conditions are met, it returns to the preset safety opening degree.

9. An automated dismantling system for cofferdam construction according to claim 8, characterized in that: The dismantling phase is tied to the range of internal and external head difference and the upper limit of the rate of change of head difference. The control unit freezes and stores boundary snapshots when switching dismantling phases, and uses the boundary snapshots as the sole parameter source for determining dismantling operation permits. The issuance of dismantling operation permits adopts continuous and stable entry conditions, and the retention adopts grace period retention conditions.

10. An automated dismantling system for cofferdam construction according to claim 9, characterized in that: The dual-channel hardware interlock connects to the dismantling equipment enable circuit via two independent contacts in series, and collects feedback from the contactor auxiliary contacts of the dismantling equipment. When the on / off state of the dual-channel hardware interlock is inconsistent with the feedback, the dismantling operation permit is revoked, and the degradation is performed in the order of interlock disconnection, pumping and recirculation to enter a safe state, and bypass current limiting and equalization. At the same time, a record entry containing the dismantling stage, boundary snapshot and trigger reason is written.

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