Experimental device and method for simulating adjacent landslides and debris flow river-blocking dam-forming cascade burst

Abstract

The invention discloses an experiment device and method for simulating adjacent landslides and debris flow river-blocking dam-forming cascade burst. The experiment device comprises a water storage tank, a main groove connected with an outlet of the water storage tank, a first branch groove, a second branch groove, a stacking platform communicated with the lower end of the main groove and a supporting frame, wherein the first branch groove and the second branch groove intersect with the main groove in the side direction; the water storage tank is positioned above the main tank and is connected with the main tank through a hinge, so that the gradient of the main tank is convenient to adjust; the bottom face of the water storage tank inclines towards the upper portion of the main water channel. In the experimental device for simulating river blocking and dam forming-cascade burst of adjacent landslides and debris flows, the gradients of the main groove and the branch grooves are adjustable, the flow of the main groove and the material type and material source quantity of the branch grooves are controllable, and the experimental device can be used for simulating the main stream blocking process of single or two landslides and debris flows of adjacent river sections or various scenes of the landslides and debris flows and the cascade burst process of a barrier dam. The formation and evolution mechanism of the landslide and debris flow river blocking dam cascade burst disaster chain can be comprehensively obtained, and the scientificity and comprehensiveness of chain generation mechanism research of the landslide and debris flow river blocking disaster chain are improved.

Description

Technical Field

[0001] The invention relates to the technical fields of geotechnical engineering and engineering geology, and in particular to an experimental device and method for simulating the cascade collapse of adjacent landslides and debris flows blocking a river and forming dams. Background Art

[0002] The plateau transition zone features dramatic terrain and fragile, weak strata. Under the influence of strong earthquakes, extreme rainfall, and human engineering activities, steep slopes along rivers in mountainous areas are prone to instability and failure. In coastal valleys, loose solid matter is susceptible to debris flows under the action of gravity and hydrodynamic forces. Landslides and debris flows, when entering rivers, form natural dams. Due to their loose structure and poor consolidation, these dams are prone to overtopping erosion or failure, triggering catastrophic floods and creating a chain reaction of disasters. In particular, when landslides and debris flows block a river in a short period of time, the cascading failure of dams can create a cumulative effect, exponentially amplifying the scale of floods and posing significant risks to critical infrastructure along the river, such as towns, roads, and energy facilities. Consequently, the research on these chain reactions has received significant attention and attention from the Chinese government.

[0003] The study of the process of landslide and debris flow blocking the river to form dams and cascading collapse and its disaster chain mechanism has always been a core scientific issue in the field of geological disaster prevention and control. At present, most of the research that has been carried out is aimed at the formation and burst flood process of a single type of dam body of landslide or debris flow. For example, CN112763182A discloses an experimental device and experimental method for the formation and burst of landslide dams. The device includes a soil sliding module, a water supply module, a water tank module and a tailings collection module; with the help of this device, the process of landslide instability accumulation into dams and dam bursts can be simulated. CN11871316A discloses a dynamic disaster test system and method for simulating the blocking of rivers and bursts by high-level landslide moraine dams. Through the landslide test system, the basin simulation system and the water supply system, the whole process of the disaster chain of accumulation formation, seepage deformation, burst evolution and dam burst flood evolution of high-level landslide moraine dams can be simulated.

[0004] In addition, CN221545460U and CN221123777U disclose experimental devices for the disaster-causing process of debris flow blocking the river at the intersection of the channel and the main river, and experimental devices for the formation and evolution process of the debris flow blocking the river dam with variable angle. Through the above devices, the angle between the water trough and the debris flow trough can be adjusted to realize the simulation of the disaster-causing process of debris flow blocking the river.

[0005] However, as described in the background technology of CN11975358A, although the existing invention device can simulate different landslide or debris flow conditions, such as speed and volume and river blocking process under different inflow angles, the simulated landslide or debris flow into the river process is inconsistent with the actual landslide or debris flow into the river process. For example, it does not take into account the material sorting effect under real terrain conditions and the superimposed structural characteristics of multi-stage accumulation bodies, and has not yet considered the landslide and / or debris flow blocking river-dam cascade failure process of adjacent river sections.

[0006] Therefore, in view of the above technical solutions, it is necessary to propose an experimental device and method to simulate the cascade collapse of adjacent landslides and debris flows blocking the river and forming dams. Summary of the Invention

[0007] In order to make up for the shortcomings of the existing technology, the present invention proposes an experimental device and method for simulating the cascade collapse of adjacent landslides and debris flows blocking the river to form dams, further restore the real situation, and improve the scientificity and accuracy of the research on the formation process of landslide and debris flow dams and the cascade collapse mechanism of dams.

[0008] The technical solution adopted by the present invention to solve its technical problem is:

[0009] An experimental device to simulate the cascade failure of adjacent landslides and debris flows blocking the river and forming dams.

[0010] It includes a water storage tank, a main trough connected to the outlet of the water storage tank, a first branch trough and a second branch trough laterally intersecting the main trough, a stacking platform connected to the lower end of the main trough, and a support frame;

[0011] The water storage tank is located above the main tank and is connected to the main tank via a hinge to facilitate slope adjustment of the main tank;

[0012] The bottom of the water storage tank is tilted towards the upper part of the main flow tank, which makes it easier for the water in the water storage tank to flow into the main tank;

[0013] The connection between the water storage tank and the main tank is provided with a groove that matches the outer diameter of the gate and is sealed with waterproof glue and other materials to achieve a close fit between the gate and the groove;

[0014] The gate is equipped with an electromagnetic flowmeter to monitor the flow rate, and a pneumatic rod to open the gate;

[0015] The water storage tank, the first branch trough and the second branch trough are all hoisted on the lower part of the support frame by an electric hoist, and the lower part of the support frame is provided with a universal wheel;

[0016] Limiting rods are provided on the first branch groove and the second branch groove.

[0017] Preferably, the side wall of the main trough is provided with a notch connected to the first branch trough and the second branch trough, and is connected to the stacking platform downstream; the side wall of the main trough is a transparent PVC board, and the bottom is a 2mm patterned steel plate, which is used to reproduce the friction resistance characteristics of the natural debris flow bed.

[0018] Preferably, the upper ends of the first branch trough and the second branch trough are equipped with material boxes and baffles, and the baffles are provided with pneumatic rods. The baffles can be opened instantly and can be used to simulate the movement and river blocking process of landslides and / or mudslides. The side walls of the first branch trough and the second branch trough are both transparent PVC boards, and the bottom is 2mm patterned steel plate. The lower ends of the first branch trough and the second branch trough are connected to the main trough.

[0019] Preferably, the stacking platform is located at the lower end of the main trough and is connected to the main trough by a hinge. The stacking platform is used to collect solid matter eroded and migrated in the main trough. The bottom of the stacking platform passes through several layers of filter screens with gradually smaller mesh sizes, and is provided with a filter and a circulation pump, and is connected to the water tank through a return pipe.

[0020] Preferably, the slopes and intersection angles of the main trough, the first branch trough and the second branch trough are adjustable, and parameters such as the flow ratio, flow velocity ratio and momentum ratio of the main trough, the first branch trough and the second branch trough are controllable. The needs of different experimental working conditions can be met through the combination of different parameters; and the adjustment of various parameters can achieve experimental effects that can only be completed by multiple physical models, avoiding the construction of multiple models and saving experimental costs; adjusting various parameters can also more comprehensively study the complete evolution process and chain generation mechanism of the landslide, mudslide and river blocking disaster chain in adjacent river sections.

[0021] Preferably, the water storage tank is supplied with water by a water pump. During the experiment, the outflow is controlled and monitored by a gate and an electromagnetic flowmeter, and the outflow is stable by the stable water level in the water tank; the water outlet of the water storage tank is slightly higher than the main trough; the bottom bed and side walls at the intersection of the main trough and the first branch trough and the second branch trough are flush, so that the materials in the first branch trough and the second branch trough can flow into the main trough in a state closer to nature.

[0022] Preferably, the first branch trough and the second branch trough can be used to simulate a scenario where adjacent landslides become unstable and block a river, or a scenario where adjacent debris flows block a river, or a combined scenario where adjacent landslides and debris flows block a river.

[0023] Preferably, a movable bottom plate is provided at the bottom of the main trough, the first branch trough and the second branch trough, and a three-axis mechanical sensor, an accelerometer and a pore water pressure sensor are arranged at the bottom of the movable bottom plate, which can capture the normal stress and shear stress exerted on the bottom bed during the movement of debris flows and burst floods, the dynamic pore water pressure inside the fluid, and the seismic signals generated by the impact of particles inside the debris flow on the bottom bed, which are difficult to monitor in nature; cameras, laser rangefinders, ultrasonic rangefinders and flowmeters are arranged on the top of the main trough, the first branch trough and the second branch trough, which are used to record and quantify the video data of the entire process of the cascade collapse of the landslide and debris flow blocking the river and the burst flood evolution, and the burst flood dynamic parameters; the side walls of the main trough, the first branch trough and the second branch trough are all provided with 5cm×5cm grid lines, which can record and quantify the movement process of the landslide and debris flow, as well as the burst of the dam and the burst fluid evolution process through high-speed camera video recording.

[0024] An experimental method based on simulating the cascade failure of adjacent landslides and debris flows blocking a river and forming a dam, comprising the following steps:

[0025] Step S1: adjusting and fixing the slopes of the main trough and the branch trough to achieve docking of the branch trough and the main trough, filling the water tank at the upper end of the main trough with water, and placing landslide debris or prepared debris flow in the material box of the branch trough;

[0026] Step S2: Cameras and sensors are deployed along the main channel and branch channels to record the process of landslides and debris flows blocking the river and the formation and failure of landslide dams, and to monitor the water and soil mechanics parameters during the movement of landslides and debris flows. All instruments are turned on at the same time to record the initial parameters before the experiment begins.

[0027] Step S3: First, open the gate of the water storage tank at the upper end of the main stream to ensure that the outflow reaches the required value for the experiment and remains stable. Then, open the material box of the branch channel to release the landslide debris flow. After the landslide debris flow moves to the main channel, it forms a barrier dam and causes water to be stored upstream. When the water flows over the barrier dam, colored plastic balls are released at intervals of 3 seconds upstream of the barrier to capture the hydrodynamic characteristics and estimate the flow velocity. Fluid samples are collected at intervals of 5 seconds downstream of the barrier to obtain the water flow density. All instruments will simultaneously record the experimental process until the shape of the barrier in the main channel no longer changes, and the experiment is terminated.

[0028] Step S4: Record the shape characteristics of the residual damming body in the main tank and the morphological characteristics of the accumulation body in the accumulation platform; clean up the restoration test site, clean up the residual damming body in the main tank, and clean up the accumulated materials in the accumulation platform;

[0029] Step S5: Compare and analyze the experimental results based on the hydraulic characteristics and videos of dam formation and cascade failure under different main and tributary river slopes or flows required by the experiment, or different landslide and debris flow scenarios.

[0030] In step S1, the slopes of the main channel and branch channels, the flow rate of the main channel, the volume and motion parameters of the landslide and debris flow in the branch channels, and the motion parameters of the burst water flow during the cascade failure of the landslide dam are all derived from natural survey statistical data and must meet the experimental similarity principle, including:

[0031] S11. Geometric similarity: The tank model and the prototype maintain a fixed geometric ratio (length, width and height);

[0032] S12, Motion similarity: The motion state (such as flow rate, acceleration, time) of the model is proportional to that of the prototype;

[0033] S13. Dynamic similarity: The force ratio of the model and the prototype must be consistent, and the dimensionless numbers (Froude number, Baigno number, Savage number and friction number) must be the same:

[0034] S14. The calculation formula of Froude number is as follows:

[0035]

[0036] Where, F r is the Froude number, v is the flow velocity, g is the acceleration of gravity, h is the flow depth, and θ is the slope;

[0037] The calculation formula of the Baigno number is as follows:

[0038] Where φ is the solid volume fraction, ρ s is the density of the particles (2650 kg / m3), d s is the average particle size of solid particles entrained by the fluid, μ f is the interstitial fluid viscosity;

[0039] The calculation formula of Savage number is as follows:

[0040] Where, ρ f is the density of the slurry (1000kg / m3), g is the acceleration due to gravity, is the internal friction angle of the solid material;

[0041] The friction number is calculated as follows:

[0042] Beneficial effects of the present invention:

[0043] 1. In the experimental device for simulating adjacent landslides and debris flows blocking a river to form a dam and then cascade failure, the slopes of the main channel and branch channels are adjustable, and the flow rate of the main channel, the material type and material source of the branch channels are controllable. This device can be used to simulate the process of blocking the main stream by a single or two landslides and debris flows in adjacent river sections, or the process of multiple scenarios of landslides and debris flows blocking the main stream, as well as the process of cascade failure of landslide dams. This is conducive to comprehensively understanding the formation and evolution mechanism of the landslide and debris flow blocking the river and the cascade failure of landslide dams, and improving the scientificity and comprehensiveness of the research on the chain mechanism of the landslide and debris flow blocking the river disaster chain.

[0044] 2. The device described in the present invention can simultaneously realize the full life cycle and full process simulation of landslide debris flow movement, blockage of main stream and cascade burst of landslide dams, and the experimental continuity is strong; in addition, the device can also simulate the initiation and movement process of burst-type and runoff-type debris flows and the process of blocking the main stream.

[0045] 3. The monitoring method proposed in the present invention can conduct targeted monitoring of the dynamic characteristics of different disaster types in the complex disaster chain of landslide-mudslide movement evolution, river blocking and dam formation, and cascade failure of landslide dams. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 It is a schematic diagram of the three-dimensional structure of the experimental device of the present invention;

[0048] Figure 2 A side view of the experimental device of the present invention;

[0049] Figure 3 A side view of the first branch slot in the experimental device of the present invention;

[0050] Figure 4 A side view of the second branch slot in the experimental device of the present invention;

[0051] Figure 5 and Figure 6 This is a comparison chart of the cascade burst flow of landslide dams in Examples 1-3 of the present invention;

[0052] Reference numerals in the figure: 1. water tank; 2. gate; 3. pneumatic rod; 4. main trough; 5. electric hoist; 6. first branch trough; 7. second branch trough; 8. stacking platform; 9. baffle; 10. limit rod; 11. universal wheel; 12. support frame. DETAILED DESCRIPTION

[0053] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0054] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0055] The following is combined with Figure 1-6 To further explain this application,

[0056] An experimental device to simulate the cascade failure of adjacent landslides and debris flows blocking the river and forming dams.

[0057] It includes a water storage tank 1, a main trough 4 connected to the outlet of the water storage tank 1, a first branch trough 6 and a second branch trough 7 laterally intersecting the main trough 4, a stacking platform 8 connected to the lower end of the main trough 4, and a support frame 12;

[0058] The water storage tank 1 is located above the main tank 4 and is connected to the main tank 4 by a hinge to facilitate the slope adjustment of the main tank 4;

[0059] The bottom surface of the water storage tank 1 is inclined toward the upper part of the main flow water tank, so that the water in the water storage tank 1 can flow smoothly into the main tank 4;

[0060] The connection between the water storage tank 1 and the main tank 4 is provided with a groove that matches the outer diameter of the gate 2 and is sealed with materials such as waterproof glue to achieve a close fit between the gate 2 and the groove;

[0061] The gate 2 is equipped with an electromagnetic flowmeter for monitoring the flow rate, and the gate 2 is provided with a pneumatic rod 3 for opening the gate 2;

[0062] The water tank 1, the first branch trough 6 and the second branch trough 7 are all hoisted on the lower part of the support frame 12 by the electric hoist 5. The lower part of the support frame 12 is provided with a universal wheel 11;

[0063] Limiting rods 10 are provided on both the first branch groove 6 and the second branch groove 7 .

[0064] The prototype of the main trough 4 is a larger river in the natural water system, and the prototypes of the first branch trough 6 and the second branch trough 7 are the first-level tributaries of the river in nature.

[0065] Furthermore, the side wall of the main trough 4 is provided with a notch connected to the first branch trough 6 and the second branch trough 7, and is connected to the stacking platform downstream; the side wall of the main trough 4 is a transparent PVC board, and the bottom is a 2mm patterned steel plate, which is used to reproduce the friction resistance characteristics of the natural debris flow bed.

[0066] Furthermore, the upper ends of the first branch trough 6 and the second branch trough 7 are equipped with material boxes and baffles 9. The baffles 9 are provided with pneumatic rods 3. The baffles can be opened instantly and can be used to simulate the movement and river blocking process of landslides and / or mudslides. The side walls of the first branch trough 6 and the second branch trough 7 are both transparent PVC boards, and the bottom is 2mm patterned steel plate. The lower ends of the first branch trough 6 and the second branch trough 7 are connected to the main trough 4.

[0067] Furthermore, the stacking platform 8 is located at the lower end of the main trough 4 and is connected to the main trough 4 by a hinge. The stacking platform 8 is used to collect solid matter eroded and migrated in the main trough 4. The bottom of the stacking platform 8 is passed through several layers of filter screens with gradually smaller mesh sizes, and is provided with a filter and a circulation pump, and is connected to the water tank 1 through a return pipe.

[0068] Furthermore, the slopes and intersection angles of the main trough 4, the first branch trough 6 and the second branch trough 7 are adjustable, and parameters such as the flow ratio, flow velocity ratio and momentum ratio of the main trough 4, the first branch trough 6 and the second branch trough are controllable. The combination of different parameters can meet the needs of different experimental conditions; the adjustment of various parameters can achieve experimental effects that can only be completed by multiple physical models, avoiding the construction of multiple models and saving experimental costs; the adjustment of various parameters can also more comprehensively study the complete evolution process and chain generation mechanism of the landslide, mudslide and river blocking disaster chain in adjacent river sections.

[0069] Furthermore, the water storage tank 1 is supplied with water by a water pump. During the experiment, the outflow rate is controlled and monitored by the gate 2 and the electromagnetic flowmeter, and the outflow rate is stable by the stable water level height in the water storage tank 1; the water outlet of the water storage tank 1 is slightly higher than the main trough 4; the bottom bed and side wall at the intersection of the main trough 4, the first branch trough 6 and the second branch trough 7 are flush, so that the substances in the first branch trough 6 and the second branch trough 7 can flow into the main trough 4 in a state closer to nature.

[0070] Furthermore, the first branch trough 6 and the second branch trough 7 can be used to simulate a scenario where adjacent landslides become unstable and block a river, or a scenario where adjacent debris flows block a river, or a combined scenario where adjacent landslides and debris flows block a river.

[0071] Furthermore, a movable bottom plate is provided at the bottom of the main trough 4, the first branch trough 6 and the second branch trough 7, and a three-dimensional mechanical sensor, an accelerometer and a pore water pressure sensor are arranged at the bottom of the bottom plate, which can capture the normal stress and shear stress exerted on the bottom bed during the movement of debris flows and burst floods, the dynamic pore water pressure inside the fluid, and the seismic signals generated by the impact of particles inside the debris flow on the bottom bed, which are difficult to monitor in nature; a camera, a laser rangefinder, an ultrasonic rangefinder and a flowmeter are arranged on the top of the main trough 4, the first branch trough 6 and the second branch trough 6, which are used to record and quantify the video data of the entire process of the cascade collapse of the landslide and debris flow blocking the river dam and the burst flood evolution, and the burst flood dynamic parameters; the side walls of the main trough 4, the first branch trough 6 and the second branch trough 7 are all provided with 5cm×5cm grid lines, which can record and quantify the movement process of the landslide and debris flow, as well as the burst of the dam body and the burst fluid evolution process through high-speed camera video.

[0072] An experimental method based on simulating the cascade failure of adjacent landslides and debris flows blocking a river and forming a dam, comprising the following steps:

[0073] Step S1: Adjust and fix the slopes of the main trough 4 and the branch troughs (the first branch trough 6 and the second branch trough 7), achieve docking of the branch troughs (the first branch trough 6 and the second branch trough 7) with the main trough 4, fill the water tank at the upper end of the main trough 4 with water, and place landslide debris or prepared debris flow in the material boxes of the branch troughs (the first branch trough 6 and the second branch trough 7);

[0074] Step S2: Cameras and sensors are deployed along the main channel 4 and the branch channels (the first branch channel 6 and the second branch channel 7) to record the process of landslides, debris flows, blocking the river, and the formation and failure of the landslide dam. At the same time, the water and soil mechanics parameters of the landslide and debris flow are monitored. Before the experiment begins, all instruments are turned on to record the initial parameters.

[0075] Step S3: First, open the gate 2 in the water storage tank 1 at the upper end of the main stream to ensure that the outflow reaches the required value for the experiment and remains stable. Then, open the material boxes of the branch troughs (the first branch trough 6 and the second branch trough 7) to release the landslide debris flow. After the landslide debris flow moves to the main trough 4, it forms a dam and causes water to accumulate upstream. When the water flows over the dam, colored plastic balls are released upstream of the dam at intervals of 3 seconds to capture the hydrodynamic characteristics and estimate the flow velocity. Fluid samples are collected downstream of the dam at intervals of 5 seconds to obtain the water flow density. All instruments will simultaneously record the experimental process until the shape of the dam in the main trough no longer changes, and the experiment is terminated.

[0076] Step S4: Record the shape characteristics of the residual damming body in the main trough 4 and the morphological characteristics of the accumulation body in the accumulation platform; clean up the reduction test site, clean up the residual damming body in the main trough, and clean up the accumulation material in the accumulation platform;

[0077] Step S5: Compare and analyze the experimental results based on the hydraulic characteristics and videos of dam formation and cascade failure under different main and tributary river slopes or flows required by the experiment, or different landslide and debris flow scenarios.

[0078] In step S1, the slopes of the main channel 4 and the branch channels (the first branch channel 6 and the second branch channel 7), the flow rate of the main channel, the volume and motion parameters of the landslide and debris flow in the branch channels, and the motion parameters of the outburst water flow during the cascade failure of the landslide dam are all derived from natural survey statistical data and must meet the experimental similarity principle, including:

[0079] S11. Geometric similarity: The tank model and the prototype maintain a fixed geometric ratio (length, width and height);

[0080] S12, Motion similarity: The motion state (such as flow rate, acceleration, time) of the model is proportional to that of the prototype;

[0081] S13. Dynamic similarity: The force ratio of the model and the prototype must be consistent, and the dimensionless numbers (Froude number, Baigno number, Savage number and friction number) must be the same:

[0082] S14. The calculation formula of Froude number is as follows:

[0083]

[0084] Where, F r is the Froude number, v is the flow velocity, g is the acceleration of gravity, h is the flow depth, and θ is the slope;

[0085] The calculation formula of the Baigno number is as follows:

[0086] Where φ is the solid volume fraction, ρ s is the density of the particles (2650 kg / m3), d s Fluid entrainment

[0087] Average particle size of solid particles, μ f is the interstitial fluid viscosity;

[0088] The calculation formula of Savage number is as follows:

[0089] Where, ρ f is the density of the slurry (1000kg / m3), g is the acceleration due to gravity, is the internal friction angle of the solid material;

[0090] The friction number is calculated as follows:

[0091] Beneficial effects of the present invention:

[0092] 1. In the experimental device for simulating adjacent landslides and debris flows blocking a river to form a dam and then cascade failure, the slopes of the main channel and branch channels are adjustable, and the flow rate of the main channel, the material type and material source of the branch channels are controllable. This device can be used to simulate the process of blocking the main stream by a single or two landslides and debris flows in adjacent river sections, or the process of multiple scenarios of landslides and debris flows blocking the main stream, as well as the process of cascade failure of landslide dams. This is conducive to comprehensively understanding the formation and evolution mechanism of the landslide and debris flow blocking the river and the cascade failure of landslide dams, and improving the scientificity and comprehensiveness of the research on the chain mechanism of the landslide and debris flow blocking the river disaster chain.

[0093] 2. The device described in the present invention can simultaneously realize the full life cycle and full process simulation of landslide debris flow movement, blockage of main stream and cascade burst of landslide dams, and the experimental continuity is strong; in addition, the device can also simulate the initiation and movement process of burst-type and runoff-type debris flows and the process of blocking the main stream.

[0094] 3. The monitoring method proposed in the present invention can conduct targeted monitoring of the dynamic characteristics of different disaster types in the complex disaster chain of landslide-mudslide movement evolution, river blocking and dam formation, and cascade failure of landslide dams.

[0095] Example 1

[0096] The experiment was based on the debris flow in Ridigou, Guza Town, Kangding City, Sichuan Province, which is a secondary tributary of the Kangding River. On August 3, 2024, a large-scale mountain torrent and debris flow disaster broke out in Ridigou, with a peak flow of about 1800m 3 / s; Among them, the debris flow activity in the right branch of Ridigou is the most intense, with an average width of 30m and an average slope of 10°. There are 6 landslide and debris flow blockage points in the ditch. Taking the right branch ditch as the prototype, according to formula 1, the width of the main ditch in the experiment is determined to be 0.4m, the width of the first branch ditch is 0.4m, and the width of the second branch ditch is 0.3m. According to formula 2, the flow rate of the main ditch is determined to be 0.05m 3 / s, and the tributary flow is 0.03m 3 In the experiment, all experimental parameters meet the principles of geometric similarity and dynamic similarity.

[0097] Experimental methods:

[0098] Step 1: Based on the experimental requirements, use the electric hoist 5 to lift the water tank 1 and main trough 4 to a slope of 10° and secure them. Adjust the slopes of the first branch trough 6 and second branch trough 7 to 30° and 15° according to the position of the main trough 4, and seamlessly connect them to the main trough 4.

[0099] Step 2: Fill the water tank 1 with water and put 0.3m behind the baffle 9 of the first trough 6. 3 Landslide debris, 0.3m 3 , bulk density is 1.8g / cm 3Debris flow material. Cameras, laser rangefinders, ultrasonic rangefinders, and flowmeters were deployed above the main stream flume 4, the first branch flume 6, and the second branch flume 7. A three-dimensional force sensor, pore water pressure sensor, and accelerometer were also deployed on the bottom of the flume floor. Before the experiment began, all instruments were turned on simultaneously and initial data was recorded.

[0100] Step 3: Open gate 2 and stabilize the flow rate of main channel 4 to 0.05m 3 / s later, the pneumatic rods 3 of the first branch trough 6 and the second branch trough 7 are opened at the same time to release the landslide and debris flow materials, and the experiment begins. After the landslide and debris flow materials slide down the branch trough, they accumulate in the main trough 4 to form a landslide dam. When the water flows over the landslide dam formed in the first branch trough 6, colored plastic balls are dropped at intervals of 3 seconds to capture the water flow dynamics and estimate the flow rate. The base pore water pressure of the burst fluid, the normal stress and shear stress exerted on the ditch bed, and the seismic signals generated during the fluid movement are captured through the deployed cameras and sensors, thereby reflecting the movement characteristics and alternating characteristics of the burst fluid. The experiment stops when the shape of the residual dam no longer changes.

[0101] Step 4: Use a handheld laser 3D scanner to monitor the morphological characteristics of the residual dam and the accumulation body on the downstream accumulation platform 8, and clean and restore the test site.

[0102] Example 2

[0103] The experimental device with the structure described in Example 1 was used to conduct a cascade failure test of adjacent landslides blocking the river. The research still used the debris flow in Ridigou, Guza Town, Kangding City, Sichuan Province as the prototype. Here, the case where an adjacent landslide blocked the right branch of Ridigou was considered. The parameters of the experimental device were adjusted as follows: the slope of the main channel 4 was adjusted to 12°, and the flow rate was set to 0.05m 3 / s, the slope of the first branch 6 is 30°, and the landslide volume behind the baffle 9 is 0.3m 3 The slope of the second branch trough 7 is 25°, and the landslide volume behind the baffle 9 is 0.4m 3 .

[0104] At the start of the experiment, landslide debris in the first branch trough (6) slid into the main trough (4) at a speed of 3 m / s, forming a 0.25 m high and 0.6 m wide landslide dam. Soil in the second branch trough slid into the main trough (4) at a speed of 2 m / s, forming a 0.3 m high and 0.7 m wide landslide dam. The formation of the first branch trough (6) dam caused the river water to stagnate, forming a barrier lake. Twenty seconds later, the dam at the first branch trough (6) overtopped and breached, and another 16 seconds later, the dam at the second branch trough (7) overtopped and breached, with the breach discharge exceeding twice the breach discharge of the first branch trough (6).

[0105] Example 3

[0106] The experimental device of the structure described in Example 1 was used to conduct the adjacent debris flow blocking the river and cascade burst test. The debris flow in Ridigou, Guza Town, Kangding City, Sichuan Province was still used as the prototype. Here, the adjacent debris flow blocking the left branch of Ridigou was considered. The parameters of the experimental device were adjusted as follows: the slope of the main channel 4 was adjusted to 7°, and the flow rate was set to 0.03m 3 / s, the slope of the first branch trough 6 is set to 20°, and the bulk density of the debris flow behind the baffle 9 is 1.8g / cm 3 , the volume is 0.3m 3 The slope of the second branch trough 6 is set to 10°, and the bulk density of the debris flow behind the baffle 9 is 1.8g / cm 3 , the volume is 0.2m 3 .

[0107] At the start of the test, debris flow in the first branch channel 6 slid into the main channel 4 at a speed of 2m / s, forming a debris flow dam 0.25m high and 1m wide. The soil in the second branch channel 7 slid into the main channel 4 at a speed of 1.5m / s, forming a debris flow dam 0.2m high and 0.9m wide. The water level upstream of the dam at the first branch channel 6 rose rapidly. After 10 seconds, the dam overtoppled and failed. Another 8 seconds later, the dam at the second branch channel 7 also overtoppled and failed. The burst flow rate of the dam at the first branch channel 6 increased by 1.25 times.

[0108] In traditional landslide or debris flow dam failure experiments, only a single dam body is often considered, and there is a lack of research on the cascade failure process, amplification mechanism, and disaster-causing characteristics of complex landslide and debris flow dam failures in natural channels. The three embodiments listed in the patent of this invention compare and analyze the adjacent landslide and debris flow blocking the river to form a dam, the adjacent landslide blocking the river to form a dam, the adjacent debris flow blocking the river to form a dam, and the dam failure process. It is found that the amplification factor of the flood under the cascade failure of the dam formed by the landslide in the adjacent river section is 1.5 times and 2 times the scale of the flood caused by the adjacent landslide and debris flow dam, and the adjacent debris flow dam (Table 1, Figure 5 and Figure 6 ).

[0109] Table 1 Comparison of flood amplification scale of different types of dam cascade process in the embodiment

[0110]

[0111] In summary, this experimental setup can be used to simulate the entire dynamic process of landslide, debris flow, and dam failure in adjacent river sections, including formation, failure, and flood evolution and accumulation. It demonstrates good consistency and provides valuable insights for simulating similar cascading landslide, debris flow, and dam failure disasters in nature. Furthermore, the various parameters in this experimental model are modifiable, allowing it to adapt to and encompass a wide range of test conditions. Construction is also short, and testing costs are low.

[0112] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. The experimental device for simulating the cascade failure of adjacent landslides and debris flows blocking a river and forming a dam is characterized by: It comprises a water storage tank (1), a main trough (4) connected to the outlet of the water storage tank (1), a first branch trough (6) and a second branch trough (7) laterally intersecting the main trough (4), a stacking platform (8) connected to the lower end of the main trough (4), and a support frame (12); The water storage tank (1) is located above the main tank (4) and is connected to the main tank (4) via a hinge, so as to facilitate the slope adjustment of the main tank (4); The bottom surface of the water storage tank (1) is inclined toward the upper part of the main flow water tank, so that the water in the water storage tank (1) can flow smoothly into the main tank (4); A groove matching the outer diameter of the gate (2) is provided at the connection between the water storage tank (1) and the main tank (4), and is sealed by a waterproof adhesive material to achieve a tight fit between the gate (2) and the groove; The gate (2) is equipped with an electromagnetic flowmeter for monitoring the flow rate, and the gate (2) is provided with a pneumatic rod (3) for opening the gate (2); The water storage tank (1), the first branch trough (6) and the second branch trough (7) are all hoisted on the lower part of the support frame (12) through the electric hoist (5), and the lower part of the support frame (12) is provided with a universal wheel (11); Limiting rods (10) are provided on both the first branch groove (6) and the second branch groove (7).

2. The experimental device for simulating cascading failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 1, characterized in that: The side wall of the main trough (4) is provided with a notch connected to the first branch trough (6) and the second branch trough (7), and is connected to the stacking platform (8) downstream; the side wall of the main trough (4) is a transparent PVC plate, and the bottom is a 2mm patterned steel plate, which is used to reproduce the friction resistance characteristics of the natural debris flow bed.

3. The experimental device for simulating cascading failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 1, characterized in that: The upper ends of the first branch trough (6) and the second branch trough (7) are both equipped with a material box and a baffle (9), the baffle (9) is provided with a pneumatic rod (3), and the baffle (9) can be opened instantly and can be used to simulate the movement of landslides and / or debris flows and the process of blocking the river. The side walls of the first branch trough (6) and the second branch trough (7) are both transparent PVC plates, and the bottom is a 2mm patterned steel plate. The lower ends of the first branch trough (6) and the second branch trough (7) are connected to the main trough (4).

4. The experimental device for simulating cascading failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 1, characterized in that: The stacking platform (8) is located at the lower end of the main trough (4) and is connected to the main trough (4) through a hinge. The stacking platform (8) is used to collect solid matter eroded and migrated in the main trough (4). The bottom of the stacking platform (8) is passed through several layers of filter screens with gradually smaller mesh sizes, and is provided with a filter and a circulation pump. The stacking platform (8) is connected to the water storage tank (1) through a return pipe.

5. The experimental device for simulating cascading failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 1, characterized in that: The slopes and intersection angles of the main trough (4), the first branch trough (6) and the second branch trough (7) are adjustable, and parameters such as the flow ratio, flow velocity ratio and momentum ratio of the main trough (4), the first branch trough (6) and the second branch trough (7) are controllable. The needs of different experimental working conditions can be met by combining different parameters. The adjustment of various parameters can achieve experimental effects that can only be completed by multiple physical models, avoiding the construction of multiple models and saving experimental costs. The adjustment of various parameters can also more comprehensively study the complete evolution process and chain generation mechanism of the landslide, debris flow and river blocking disaster chain in adjacent river sections.

6. The experimental device for simulating cascading failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 1, characterized in that: The water storage tank (1) is supplied with water by a water pump. During the experiment, the outflow rate is controlled and monitored by the gate (2) and the electromagnetic flowmeter, and the outflow rate is ensured to be stable by the stable water level in the water storage tank (1). The water outlet of the water storage tank 1 is slightly higher than the main trough (4). The bottom bed and the side wall at the intersection of the main trough (4), the first branch trough (6) and the second branch trough (7) are flush, so that the substances in the first branch trough (6) and the second branch trough (7) can flow into the main trough (4) in a state closer to nature.

7. The experimental device for simulating cascading failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 1, characterized in that: The first branch trough (6) and the second branch trough (7) can be used to simulate a scenario where adjacent landslides become unstable and block a river, or a scenario where adjacent debris flows block a river, or a combined scenario where adjacent landslides and debris flows block a river.

8. The experimental device for simulating cascading failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 1, characterized in that: The bottom of the main trough (4), the first branch trough (6) and the second branch trough (7) are provided with a movable bottom plate, and the bottom of the movable bottom plate is provided with a three-dimensional mechanical sensor, an accelerometer and a pore water pressure sensor, which can capture the normal stress and shear stress applied to the bottom bed during the movement of debris flow and burst flood, the dynamic pore water pressure inside the fluid, and the seismic signals generated by the impact of particles inside the debris flow on the bottom bed, which are difficult to monitor in nature; the top of the main trough (4), the first branch trough (6) and the second branch trough (6) are provided with a camera, a laser rangefinder, an ultrasonic rangefinder and a current meter, which are used to record and quantify the video data of the whole process of landslide and debris flow blocking the river - cascade burst of the landslide dam - burst flood evolution and the burst flood dynamic parameters; the side walls of the main trough (4), the first branch trough (6) and the second branch trough (7) are all provided with 5cm×5cm grid lines, which can record and quantify the movement process of landslide and debris flow, as well as the burst of the landslide dam and the burst fluid evolution process through high-speed camera video.

9. The experimental method for simulating the cascade failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in any one of claims 1 to 8, comprising the following steps: Step S1: Adjust and fix the slopes of the main trough and the branch trough to achieve docking between the branch trough and the main trough, fill the water tank at the upper end of the main trough with water, and put landslide debris or prepared debris flow into the material boxes of the first and second branch troughs; Step S2: Cameras and sensors are deployed along the main channel and branch channels to record the process of landslides and debris flows blocking the river and the formation and failure of the landslide dam, and to monitor the water and soil mechanics parameters during the movement of the landslides and debris flows. All instruments are turned on at the same time before the experiment begins to record the initial parameters. Step S3: First, open the gate of the water storage tank at the upper end of the main stream to ensure that the outflow reaches the required value for the experiment and remains stable. Then, open the material box of the branch channel to release the landslide debris flow. After the landslide debris flow moves to the main channel, it forms a barrier dam and causes water to be stored upstream. When the water flows over the barrier dam, colored plastic balls are released at intervals of 3 seconds upstream of the barrier to capture the hydrodynamic characteristics and estimate the flow velocity. Fluid samples are collected at intervals of 5 seconds downstream of the barrier to obtain the water flow density. All instruments will simultaneously record the experimental process until the shape of the barrier in the main channel no longer changes, and the experiment is terminated. Step S4: Recording the shape characteristics of the residual dam in the main channel and the morphological characteristics of the accumulation body in the accumulation platform; Clean up the reduction test site, clean up the remaining dam in the main trough, and clean up the accumulated materials in the accumulation platform; Step S5: Compare and analyze the experimental results based on the hydraulic characteristics and videos of dam formation and cascade failure under different main and tributary river slopes or flows required by the experiment, or different landslide and debris flow scenarios.

10. The experimental method for simulating cascade failure of adjacent landslides and debris flows blocking a river and forming a dam as claimed in claim 9, characterized in that: In step S1, the slopes of the main channel and branch channels, the flow rate of the main channel, the volume and motion parameters of the landslide and debris flow in the branch channels, and the motion parameters of the burst water flow during the cascade burst of the landslide dam are all derived from natural survey statistical data and must meet the experimental similarity principle, specifically including: S11. Geometric similarity: The geometric dimensions of the tank model and the prototype should maintain a fixed ratio; S12, Motion similarity: The motion state of the model is proportional to that of the prototype; S13. Dynamic similarity: The force ratio of the model and the prototype must be consistent, and the dimensionless numbers must be the same: S14. The calculation formula of Froude number is as follows: Where, F r is the Froude number, v is the flow velocity, g is the acceleration of gravity, h is the flow depth, and θ is the slope; The calculation formula of the Baigno number is as follows: Where φ is the solid volume fraction, ρ s is the density of the particle, d s is the average particle size of solid particles entrained by the fluid, μ f is the interstitial fluid viscosity; The calculation formula of Savage number is as follows: Where, ρ f is the density of the slurry, g is the acceleration due to gravity, is the internal friction angle of the solid material; The friction number is calculated as follows:

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