Automatically-controlled multistage interlocking debris flow blocking dam system

Abstract

The invention discloses an automatically-controlled multi-stage interlocking debris flow blocking dam system, and aims to change the blocking sequence of an original debris flow blocking dam, start to intercept from a dam body at the lowest position, gradually intercept upwards, and facilitate subsequent cleaning of deposited bodies behind the dam from the downstream to the upstream along a channel. At the beginning of the occurrence of debris flow, the blocking dams of the second stage and above are all in an open state, the debris flow begins to deposit from the blocking dam of the first stage, when the deposition parameter of the blocking dam of the first stage reaches a preset threshold value, the automatic control unit controls the gate of the adjacent blocking dam of the second stage to be closed, and the blocking dam of the second stage intercepts the debris flow; and when the siltation parameter of the second-stage blocking dam reaches a preset threshold value, the automatic control unit continues to control the gate of the third-stage blocking dam to be closed until siltation of the uppermost-stage blocking dam is completed, and therefore multi-stage linkage interception is completed.

Description

Technical Field

[0001] This invention belongs to the field of geological disaster prevention and control technology, specifically relating to an automatically controlled multi-stage interlocking debris flow barrier dam system. Background Technology

[0002] Debris flows are a common geological disaster in mountainous areas, characterized by sudden onset, enormous energy, and high destructiveness, easily causing gully blockage, road damage, and even casualties. Currently, the main method for preventing and controlling debris flows is through barrier dam structures, which intercept solid particles in the debris flow and slow its velocity.

[0003] In debris flow disaster prevention and control, barrier dam groups are a commonly used engineering measure. The working principle of traditional debris flow barrier dam groups is that when a debris flow occurs, sediment first accumulates at the upstream barrier dam. Once the upstream barrier dam is full, the debris flow continues to flow downstream, where sediment begins to accumulate at the next barrier dam, and so on, until the downstream barrier dam becomes effective.

[0004] However, this traditional design has significant flaws. The total reservoir capacity of the dam group is determined by the total amount of fluid material under the most unfavorable operating conditions within the project's service life, taking into account a redundancy factor. However, in reality, debris flow outbreaks often fail to reach the design limits, and siltation frequently only fills a few upstream dams. To maintain the maximum reservoir capacity of the dam group, frequent dredging of silt behind the upstream dams is necessary. However, in mountainous areas prone to debris flows, poor road conditions result in high manpower and material costs, low efficiency, and high expenses for dredging operations. Especially in high-altitude areas, the lack of road networks and thin air make clearing debris flows at the highest points of mountains extremely difficult and require substantial manpower and resources. Summary of the Invention

[0005] This invention provides an automatically controlled multi-stage interlocking debris flow barrier dam system, which aims to change the original barrier sequence of debris flow barrier dams, starting the interception from the lowest point of the dam body and intercepting it upwards step by step, so as to facilitate the subsequent clearing of the silt behind the dam from downstream to upstream along the gully.

[0006] Therefore, the present invention adopts the following technical solution: An automatically controlled multi-level interlocking debris flow barrier dam system consists of N multi-level interlocking debris flow barrier dams arranged sequentially from low to high elevation along the ditch. The downstream barrier dam is the first-level barrier dam, the next level is the second-level barrier dam, and so on, with the upstream dam being the Nth-level barrier dam. The first-level retaining dam is equipped with monitoring components but no gates. Each of the remaining retaining dams is equipped with gates and monitoring components, as well as automatic control units connected to the monitoring components and gate signals respectively. The monitoring components are used to collect the sedimentation parameters of debris flows within the corresponding retaining dam in real time. The automatic control units control the opening and closing of the gates of the next higher-level retaining dam based on the sedimentation parameters of the current retaining dam. At the beginning of a debris flow, all retaining dams from the second level onwards are open. Debris flows begin to accumulate from the first-level retaining dam. When the sedimentation parameters of the first-level retaining dam reach a preset threshold, the automatic control unit controls the gates of the adjacent second-level retaining dam to close, thus intercepting the debris flow. When the sedimentation parameters of the second-level retaining dam reach the preset threshold, the automatic control unit continues to control the gates of the third-level retaining dam to close, until the top-level retaining dam has completed sedimentation, thereby completing multi-level linkage interception.

[0007] Furthermore, the monitoring components include active monitoring units and passive monitoring units. The active monitoring units include acoustic sensors, radar sensors, and laser rangefinders; the passive monitoring units include fiber optic level sensors and piezoelectric sensors. The active monitoring units are installed on the top of the dam body, and the passive monitoring units are installed on the water-facing side of the dam body.

[0008] Furthermore, the gate is a hydraulic flap gate, and the automatic control unit is connected to the hydraulic flap gate through a drive module to control the opening or closing of the hydraulic flap gate.

[0009] Furthermore, it also includes a debris flow early warning system and a manual control system; The debris flow early warning system includes multiple infrasound sensors deployed in the valley. When a debris flow occurs, infrasound is released. The infrasound sensors receive the signals and send them to the debris flow early warning system processor, which determines whether a debris flow has occurred based on the infrasound signals. When a debris flow occurs, the debris flow early warning system issues an alarm to alert the staff. Visible light and infrared cameras are also installed on the dam body. The data collected by the cameras is transmitted back to the large screen in the control room in real time, and the large screen displays the debris flow status inside the dam body in real time. The control room is also equipped with switches for manually controlling the opening or closing of each gate. According to the operation needs, in case of emergency, the operator can manually control each gate to close. The operation priority of the manual control system is higher than that of the automatic control unit.

[0010] Furthermore, the distance between two adjacent retaining dams is 50-200 meters, and the distance is adjusted reasonably according to the slope. The distance between retaining dams is smaller in areas with steep slopes and larger in areas with gentle slopes. The height of the retaining dam is 5-8 meters.

[0011] Furthermore, the design threshold for concrete siltation is 60%-85% of the effective reservoir capacity of the corresponding retaining dam.

[0012] The beneficial effects of this invention are as follows: 1. In conventional methods, debris flows begin to accumulate at the upstream dam. Once the upstream dam is full, the debris flow crosses the dam and continues downstream, accumulating at the next dam, and so on, from upstream to downstream. This application changes the debris flow interception order. The debris flow flows through an open gate to the downstream first-stage dam, accumulating first at this downstream first-stage dam. When the accumulation parameters reach a preset threshold, the upstream second-stage gate is closed, and the debris flow is then intercepted by this second-stage dam. When the sedimentation parameters reach the preset threshold, the gate of the third-level barrier dam continues to be closed, and so on to complete the multi-level linkage interception; the sedimentation process is changed to sedimentation from downstream to upstream; the technical effect is that when the debris flow is limited, the debris flow in the prior art is sedimented upstream, while the debris flow in this application is sedimented downstream; the prior art requires cleaning from upstream, and it is difficult for personnel and vehicles to reach the site, making cleaning difficult; while this application can start cleaning from the lowest level, and it is easier for personnel and vehicles to enter the site, greatly reducing the difficulty of debris flow dredging and reducing dredging costs; 2. The monitoring components include active monitoring units and passive monitoring units. The active monitoring units include acoustic sensors, radar sensors, and laser rangefinders; the passive monitoring units include fiber optic level sensors and piezoelectric sensors. The system employs real-time sensor monitoring coupled with an automatic control unit. The automatic control unit compares the values ​​monitored by each sensor with pre-designed thresholds to control the gate closure. The gate opening and closing response time is short, allowing for rapid switching of the intercepting main body before the lower-level dam body is filled, significantly improving the automation control level of the barrier dam system and enhancing the accuracy of its operation.

[0013] 3. This application also includes a debris flow early warning system and a manual control system; when a debris flow occurs, the debris flow early warning system issues an alarm to alert personnel; depending on the site conditions, personnel can bypass the automatic control unit and control the closure of each gate through the manual control system, with the manual control system having higher priority than the automatic control unit. The manual control system improves the reliability and resilience of the retaining dam system; if the automatic control unit malfunctions or encounters other problems, personnel can intervene manually. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the layout of the debris flow barrier dam of the present invention; Figure 2 This is a schematic diagram of the layout of the gates on the dam according to the present invention; Figure 3 This is a schematic diagram of the sensor layout for the passive monitoring unit on the water-facing side of the retaining dam according to the present invention. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: An automatically controlled multi-stage interlocking debris flow barrier system comprises N interlocking debris flow barrier dams (N≥2) arranged sequentially along the ditch from low to high elevation. The downstream barrier dam is the first-stage barrier dam, the next upstream is the second-stage barrier dam, and so on, with the upstream dam being the Nth-stage barrier dam. The spacing between adjacent barrier dams is 50-200 meters, adjusted according to the slope; the spacing is smaller in steeper slopes and larger in gentler slopes. The barrier dams are 5-8 meters high and constructed of reinforced concrete.

[0016] The first-level retaining dam is equipped with monitoring components but no gates. Each subsequent retaining dam is equipped with gates and monitoring components, as well as automatic control units connected to the monitoring components and gate signals respectively. The monitoring components are used to collect the sedimentation parameters of debris flows within the corresponding retaining dam in real time. The automatic control unit controls the opening and closing of the gates of the downstream first-level retaining dam based on the sedimentation parameters of the downstream first-level retaining dam. When the sedimentation parameters of the downstream first-level retaining dam reach a preset threshold, the automatic control unit controls the gate of the adjacent second-level retaining dam to close, thus intercepting the debris flow. When the sedimentation parameters of the second-level retaining dam reach the preset threshold, the automatic control unit continues to control the gate of the third-level retaining dam to close, and so on, to complete the multi-level linkage interception. The concrete sedimentation threshold is set at 60%-85% of the effective reservoir capacity of the corresponding retaining dam.

[0017] The gate's specific structure is as follows: The gate is a hydraulic flap gate. The automatic control unit is connected to the hydraulic flap gate via a drive module to control the full opening or closing of the hydraulic flap gate. To prevent the gate from failing to close due to hydraulic flap valve malfunction, the gate and auxiliary equipment need to be inspected regularly.

[0018] The specific structure of the monitoring component is as follows: The monitoring component includes an active monitoring unit and a passive monitoring unit. The active monitoring unit includes an acoustic sensor, a radar sensor, and a laser ranging sensor; the passive monitoring unit includes a fiber optic level sensor and a piezoelectric sensor.

[0019] 1. Active monitoring unit 1.1 The acoustic wave sensor emits ultrasonic waves and receives the echoes reflected from the surface of the debris flow, calculating the propagation time to determine the height. Its advantages include: non-contact measurement, avoiding direct contact with mud and rocks, and installation on an unobstructed location on the outside of the dam.

[0020] The acoustic wave sensor is fitted with a protective shell with a hydrophobic and non-stick coating to prevent mud from covering the probe. Multiple sets are evenly distributed to avoid misjudgment by a single probe being blocked by a boulder.

[0021] 1.2 The radar sensor emits microwave signals and utilizes the Doppler effect and echo time difference to accurately measure the surface height of debris flows. Its advantages include: strong penetration, unaffected by rain, fog, or mud splashes, superior impact resistance compared to ultrasonic waves, and a measurement distance of 0-10m, fully covering the dam height requirements.

[0022] During installation, avoid obstruction by the dam structure and tilt the probe downwards at a angle of 15-30° to reduce ground clutter interference.

[0023] 1.3 Laser Ranging Sensor: Emits a laser beam onto the debris flow surface and calculates the height based on the time difference of the reflected light, achieving a measurement accuracy of ±1mm. Advantages: Accurate measurement over short distances (0-5m), suitable for scenarios with low dam heights (3-5m), and fast response speed (≤1ms).

[0024] The laser sensor is equipped with a dustproof and shockproof protective cover to prevent the laser probe from being damaged by dust or small stones in the mudslide. In severe weather (heavy rain, strong fog), it needs to be linked with other sensors for verification.

[0025] 2. Passive monitoring unit 2.1 Fiber Bragg Grating Level Sensor: The fiber Bragg grating is encapsulated within an elastic probe. When a debris flow submerges the probe, the probe deforms under pressure, causing the grating wavelength to shift. The height is then calculated using a demodulator. It is resistant to electromagnetic interference and corrosion, and can be embedded in the concrete of the dam sidewall, integrating with the dam structure and is not easily damaged by falling rocks.

[0026] Installation location: As an auxiliary sensor, it is deployed in the lower part of the dam body to monitor the debris flow rising process, complementing the radar / ultrasonic sensor.

[0027] 2.2 Piezoelectric sensor: The piezoelectric sensor is installed in the upper part of the dam body and works in conjunction with the fiber optic grating level sensor; the piezoelectric sensor signal is triggered only when the impact force is greater than or equal to the preset pressure value (confirming that it is a debris flow rather than water accumulation / rockfall). The preset pressure value is obtained through test.

[0028] The automatic control unit includes a controller and a communication module. The communication module receives data collected by each monitoring component and sends control commands to the drive modules of each gate. The controller is located in a control room in a safe location. Signal transmission can be wired or wireless. Wired transmission can use fiber optic signals for easy cabling. If wireless signals are used, base stations need to be built along the valley to ensure signal stability, and the signal is transmitted to the control room via the wireless module.

[0029] The work process is as follows: Normal state: The gates of the barrier dam are all fully open, and normal water flow such as rainwater in the ditch can pass through smoothly without any drainage obstruction.

[0030] In the early stages of a debris flow: the debris flow moves from high to low along the ditch, passing through the Nth level barrier dam and the N-1th level barrier dam in sequence, and finally flows into the downstream first level barrier dam, where the first level barrier dam begins to intercept the solid material of the debris flow.

[0031] First-level linkage: When debris flow accumulates in the first-level barrier dam, the fiber optic grating level sensor is triggered first. As the height continues to rise, the piezoelectric sensor is triggered. As the height continues to rise, the acoustic sensor, radar sensor, and laser rangefinder simultaneously monitor the debris flow accumulation height. When the height reaches the set threshold, the monitoring components transmit the signal to the automatic control unit. After receiving the signal, the controller immediately sends a closing command to the gate of the second-level barrier dam. The gate of the second-level barrier dam quickly and completely closes, and subsequent debris flows are intercepted by the second-level barrier dam.

[0032] Second-level linkage: The monitoring components on the second-level barrier dam synchronously begin monitoring the height of debris flow accumulation. When the height reaches the set threshold, the monitoring components send a signal to the automatic control unit, and the controller sends a closing command to the gate of the third-level barrier dam. The third-level barrier dam begins to intercept the debris flow, and so on, with each level of linkage closing the gate.

[0033] After the debris flow ends: The automatic control unit remotely sends an opening command to open each gate in descending order of height, facilitating the clearing of solid materials trapped inside the dam.

[0034] Redundancy design: It also includes a debris flow early warning system and a manual control system.

[0035] The debris flow early warning system includes multiple infrasound sensors deployed in the valley. When a debris flow occurs, they release infrasound waves. The infrasound sensors receive the signals and send them to the control room, which determines whether a debris flow has occurred based on the infrasound signals. When a debris flow occurs, the control room issues an alarm, allowing personnel inside to monitor the situation remotely.

[0036] The control room houses the controllers, and the dam itself is equipped with visible light and infrared cameras. Data collected by these cameras is transmitted in real-time to a large screen in the control room, which displays live video feeds of the area behind the dam. The control room also includes switches for manually opening and closing each gate; in case of emergency, operators can manually close the gates.

[0037] Implementation Cases

[0038] 1.1 Project Location and Mission Background The project area is located in a county, with a river flowing from west to east along its south side. The river's first-level tributary basin has steep banks, a large gradient, and severely weathered mountain surfaces, making it prone to landslides and collapses. The gully contains abundant loose solid material, increasing the likelihood and danger of debris flows, with the potential for large-scale debris flow disasters at any time. This seriously threatens a proposed resettlement area at the gully mouth, a large construction site, a national highway reconstruction project, a county irrigation canal, a photovoltaic power station, and a large amount of farmland and residential buildings at the gully mouth, affecting approximately 1040 people and threatening assets worth 20 million yuan (based on on-site investigation and interviews). Historically, this area has experienced numerous debris flow disasters and is considered a debris flow-prone region. Given the large number of people and significant assets at risk, the management of this debris flow gully is urgent and of great importance.

[0039] 1.2 Survey and Design of Retaining Dam Scheme The five debris flow gullies in the survey area span multiple villages. Debris flows N01 to N05 in the survey area are all classified as stormwater-driven gully debris flows. Based on their frequency of occurrence, they are medium-frequency debris flows, and their development stage is considered mature. Through field investigations, experiments, and calculations, this paper focuses on the management of debris flow N01 as an example. The bulk density of debris flow N01 is 1.54 t / m³. 3 The total volume of a single debris flow event in the main gully, occurring once every 100 years, is 2.35 × 10⁻⁶. 4 m 3 The solid material ejected by a single mudslide is 0.99 × 10⁻⁶. 4 m 3 The debris flow was of medium size.

[0040] The N01 gully project is laid out as follows: 6 retaining dams + M10 masonry block embankment + culvert + water-crossing roadway are constructed in the N01 debris flow gully.

[0041] 1.3 Basis for Dam Site Layout and Selection The dam site is selected in the middle and lower reaches of the gully and the tributary gully with gentle longitudinal slopes, symmetrical valleys, and open upstream areas. The dam foundation soil is composed of gravel, which can meet the foundation bearing capacity requirements. The slopes on both sides of the gully are stable, the left and right dam shoulders are composed of gravel, and there are no adverse geological processes such as landslides or gullies and no groundwater outbursts in the surrounding area. The height can meet the requirements of dam height and reservoir capacity, and there is a relatively open construction site or working face.

[0042] 1.4 Section Design The retaining dams are trapezoidal in cross-section, with a height of 8m each, totaling 6 dams. The top width of each dam is 1.0m, and the foundation depth is 2.0m. The slope of the water-facing side is designed to be 1:0.4, and the slope of the water-returning side is designed to be 1:0.1.

[0043] 1.5 Dam Height Design Based on the characteristics of debris flow solid material replenishment, the height of the retaining dam is designed to raise the erosion base level after siltation and retain most of the loose solid material. The dam height is determined comprehensively based on factors such as the amount of sediment retained, the stabilization of the upstream gully slope after siltation, and the widening of the gully bed. The calculation formula used for the dam height design is as follows: H 1 = L 1 ( i 0 - i′ ) In the formula: H 1 —Calculate the dam height (m); L 1 —The distance between two adjacent dams or the siltation distance determined comprehensively (m); i 0 —Original longitudinal slope of the ditch bed (in decimals); i′ —Longitudinal slope of siltation in the ditch bed (in decimals), according to empirical formula i′ =0.7 i 0 ; 1.6 Sensor Deployment During the construction of the retaining dam, fiber optic level sensors and piezoelectric sensors are installed on the water-facing side of the dam body; the fiber optic level sensors are installed at the lower two-thirds, and the piezoelectric sensors are installed at the upper one-third (e.g., Figure 3 A support frame is installed on the top of the dam, on which acoustic sensors, radar sensors, and laser rangefinders are fixed. The acoustic sensors are fitted with protective housings coated with a hydrophobic, non-stick coating. The radar sensor probes are tilted downwards at 15-30°. The laser sensors are fitted with dustproof and impact-resistant protective covers. After each debris flow interception, any damaged sensors must be replaced promptly.

Claims

1. An automatically controlled multi-stage interlocking debris flow barrier dam system, characterized in that, N multi-level interlocking debris flow barrier dams are arranged in sequence from low to high elevation along the ditch. The downstream barrier dam is the first level barrier dam, the next level is the second level barrier dam, and so on, with the upstream dam being the Nth level barrier dam. The first-level retaining dam is equipped with monitoring components but no gates. Each of the remaining retaining dams is equipped with gates and monitoring components, as well as automatic control units connected to the monitoring components and gate signals respectively. The monitoring components are used to collect the sedimentation parameters of debris flows within the corresponding retaining dam in real time. The automatic control units control the opening and closing of the gates of the next higher-level retaining dam based on the sedimentation parameters of the current retaining dam. At the beginning of a debris flow, all retaining dams from the second level onwards are open. Debris flows begin to accumulate from the first-level retaining dam. When the sedimentation parameters of the first-level retaining dam reach a preset threshold, the automatic control unit controls the gates of the adjacent second-level retaining dam to close, thus intercepting the debris flow. When the sedimentation parameters of the second-level retaining dam reach the preset threshold, the automatic control unit continues to control the gates of the third-level retaining dam to close, until the top-level retaining dam has completed sedimentation, thereby completing multi-level linkage interception.

2. The automatically controlled multi-stage interlocking debris flow barrier dam system according to claim 1, characterized in that, The monitoring components include active monitoring units and passive monitoring units. The active monitoring units include acoustic sensors, radar sensors, and laser rangefinders; the passive monitoring units include fiber optic level sensors and piezoelectric sensors. The active monitoring units are installed on the top of the dam body, and the passive monitoring units are installed on the water-facing side of the dam body.

3. The automatically controlled multi-stage interlocking debris flow barrier dam system according to claim 2, characterized in that, The gate is a hydraulic flap gate. The automatic control unit is connected to the hydraulic flap gate through a drive module and is used to control the opening or closing of the hydraulic flap gate.

4. The automatically controlled multi-stage interlocking debris flow barrier dam system according to claim 1, characterized in that, It also includes a debris flow early warning system and a manual control system; The debris flow early warning system includes multiple infrasound sensors deployed in the valley. When a debris flow occurs, infrasound is released. The infrasound sensors receive the signals and send them to the debris flow early warning system processor, which determines whether a debris flow has occurred based on the infrasound signals. When a debris flow occurs, the debris flow early warning system issues an alarm to alert the staff. Visible light and infrared cameras are also installed on the dam body. The data collected by the cameras is transmitted back to the large screen in the control room in real time, and the large screen displays the debris flow status inside the dam body in real time. The control room is also equipped with switches for manually controlling the opening or closing of each gate. According to the operation needs, in case of emergency, the operator can manually control each gate to close. The operation priority of the manual control system is higher than that of the automatic control unit.

5. The automatically controlled multi-stage interlocking debris flow barrier dam system according to claim 1, characterized in that, The distance between two adjacent retaining dams is 50-200 meters. The distance is adjusted according to the slope. The distance between retaining dams is smaller in areas with steep slopes and larger in areas with gentle slopes. The height of the retaining dam is 5-8 meters.

6. The automatically controlled multi-stage interlocking debris flow barrier dam system according to claim 1, characterized in that, The design threshold for concrete siltation is 60%-85% of the effective reservoir capacity of the corresponding retaining dam.

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