Physical model test device and method for silo effect of ice-rock avalanche debris flow based on ice gully terrain

Abstract

The application provides an ice-rock avalanche debris flow silo effect physical model test device and method based on a cirque terrain, and belongs to the field of debris flow disaster simulation. The device comprises a chute with a predetermined inclination angle with the ground; the upper flow passage of the chute is provided with solid side walls on both sides, and the lower part is provided with suspended side rods on both sides, forming a rectangular hollow; a rectangular steel frame is symmetrically embedded in the rectangular hollow on both sides; the height of the rectangular steel frame is lower than the height of the rectangular hollow, and a plurality of horizontal guide rail walls perpendicular to the side rods and parallel to the short sides are arranged in the rectangular steel frame; a spacer with the same height as the gap is arranged at the intersection of the horizontal guide rail wall and the side rod, and a guide rail roller is arranged on the lower side of the spacer, so that the horizontal guide rail wall can move horizontally perpendicular to the side rod along the guide rail roller; side erosion samples are symmetrically arranged on the upper part of the chute and the top of the rectangular steel frame, forming a variable-angle funnel-shaped side erosion channel. The application effectively improves the simulation authenticity and accuracy of the ice-rock avalanche debris flow under the cirque terrain.

Description

Technical Field

[0001] This invention belongs to the field of debris flow disaster simulation, specifically relating to a physical model test device and method for ice and rock collapse debris flow silo effect based on cirque topography. Background Technology

[0002] Ice avalanches are natural disasters caused by the detachment of thick, in-situ ice or rock masses from their parent body due to frost heave, cracking, or other factors, resulting in the collapse, tumbling, and sliding of the ice from steep glaciers. They often occur at glacier termins or on high, steep rock formations. The debris formed during an ice avalanche mixes with meltwater to create a sedimentary gravity flow, or debris flow, which exhibits plastic rheological properties and laminar flow characteristics and is extremely destructive.

[0003] In cirque topography similar to the above-mentioned areas, the characteristics of ice-rock debris flow disasters are mainly as follows: (1) They are widely developed in cirque topography, which significantly affects the fluidity and dynamic disaster characteristics of ice-rock debris flows. Especially in the near-funnel-shaped topography at the entrance of the flow area, the flow of debris flows often exhibits a significant silo effect; (2) The silo effect significantly changes the internal stress state of the debris flow body, leading to the formation of dynamic arches, which to some extent hinders the flow of debris flows; (3) The silo effect greatly increases the lateral pressure of the debris flow body on the sidewall of the channel, promotes the occurrence of lateral erosion, significantly expands the volume of the disaster-causing body, and often exhibits a significant blockage effect after lateral erosion, which improves the fluidity of the debris flow and enhances the disaster impact range in a short period of time. Therefore, revealing the influence of the silo effect on the dynamic disaster mechanism of high-altitude long-distance ice-rock debris flows under cirque topography is one of the key points to achieve accurate risk assessment of this type of disaster. However, the silo effect of debris flow under cirque topography is difficult to record and capture in real time in the field, making it impossible to effectively analyze dynamic arching, enhanced lateral erosion, and related plugging effects.

[0004] In existing technologies, debris flow models are generally used to simulate corresponding disaster types. For example, Chinese patent CN119901900B discloses a high-altitude landslide debris flow test model device, including: an operating support, which includes an upper plate and a lower support frame; a landslide simulation body is rotatably mounted in a rectangular window on the upper plate of the operating support; a slope adjustment drive is fixedly mounted on the upper right side of the operating support, which can drive the landslide simulation body to adjust its slope; a slope adjustment drive is mounted on the upper right side of the operating support; and a drive component is mounted on a support rod on the lower side of the operating support, which can drive the slope adjustment drive and the slope adjustment drive to work. Through the drive component, power can be provided to the slope adjustment drive or the slope adjustment drive as needed during the simulation test, allowing one drive structure to drive and adjust two adjustment components in the simulation test, reducing the number of drive structures required for the simulation device. However, the above-mentioned devices have only been optimized in terms of structure and cannot effectively reflect the impact of cirque topography on debris flow. At the same time, the existing model test devices also lack research on the lateral erosion effect of debris flow and mostly focus on the lateral erosion and scraping of the substrate. They also lack strength control devices for lateral erosion samples and the acquisition of lateral erosion data, thus failing to truly reflect the actual debris flow and resulting in poor risk assessment. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, the present invention aims to provide a physical model test device and method for ice-rock debris flow silo effect based on cirque topography. By adding a translational rectangular steel frame and lateral erosion specimen in the chute, a funnel-shaped lateral erosion channel with variable angle is formed, thereby accurately simulating the ice-rock debris flow process under cirque topography.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] In a first aspect, embodiments of the present invention provide a physical model test device for the silo effect of ice-rock avalanche debris flow based on cirque topography. The device includes: a hopper 1, a first hydraulic cylinder 2, a second hydraulic cylinder 3, a rectangular steel frame 4, a lateral erosion sample 5, a transparent baffle 6, a normal cylinder 7, guide rail rollers 8, a bottom plate for accumulation 9, a chute 10, and high-speed cameras installed at various locations; wherein...

[0008] The chute 10 is placed at a predetermined angle to the ground, connected to the hopper 1 at the high end and to the stacking bottom plate 9 at the low end; a first hydraulic cylinder 2 is provided under the hopper 1, and a second hydraulic cylinder 3 is provided on the lower side of the middle part of the chute 10.

[0009] The slide 10 is divided into an upper flow area and a lower flow area. The upper flow area has solid side walls 102 on both sides, and the lower flow area has suspended side rods 103 on both sides. A rectangular hollow is formed on both sides of the lower flow area of ​​the slide 10. The side rods 103 are connected to the side walls 102 and are extensions of the upper edge of the side walls 102.

[0010] A rectangular steel frame 4 is symmetrically embedded in each of the two rectangular cutouts. The height of the rectangular steel frame 4 is lower than the height of the rectangular cutout. The short side of the steel frame is perpendicular to the side rod 103, and the long side is parallel to the side rod 103. The lower part of the rectangular steel frame 4 extends to the stacking base plate 9. Several transverse guide rail walls 42 are set inside each rectangular steel frame 4, which are perpendicular to the side rod 103 and parallel to the short side. At the position where the transverse guide rail wall 42 intersects with the side rod, a pad 45 with the same height as the gap is set, and a guide rail roller 8 is installed on the lower side of the pad 45, so that the transverse guide rail wall 42 can move perpendicularly to the side rod 103 along the guide rail roller 8.

[0011] On the upper flow area of ​​the chute 10, at the top of the rectangular steel frame 4, symmetrical side corrosion samples 5 are arranged, and the side corrosion samples 5 on both sides form a funnel-shaped side corrosion channel with variable angle.

[0012] In a preferred embodiment of the present invention, each side-corrosion sample 5 is a debris-like particle accumulation. The accumulation has the bottom of the chute as its bottom surface and the transparent baffle 6 as its top surface. The cross-section is a right-angled triangle shape. The two mutually right-angled boundaries are the chute sidewall 102 and the top of the steel frame 41, respectively. The other inclined side is a free side, which participates in the side-corrosion process as the side-corrosion side. The angle between the side-corrosion side and the chute sidewall 102 is the side-corrosion inclination angle. The height of the side-corrosion sample 5 is lower than that of the rectangular steel frame 4. A normal hydraulic cylinder 7 is provided on the transparent baffle 6. A reaction frame 101 is provided on the chute 10 at the position corresponding to the normal hydraulic cylinder 7. The top of the hydraulic cylinder is connected to the reaction frame 101.

[0013] In a preferred embodiment of the present invention, the normal cylinder 7 includes two groups, each group of normal cylinder 7 includes at least two hydraulic rods, the two hydraulic rods are arranged longitudinally and parallel to the side of the slide groove; the first hydraulic rods of each group have the same height, and the second hydraulic rods have the same height.

[0014] In a preferred embodiment of the present invention, a pressure sensor 71 is provided at the hydraulic rod of the normal cylinder 7 to control the shear strength of the lateral corrosion sample 5 through the reaction frame 101, the normal cylinder 7 and the transparent baffle 6.

[0015] In a preferred embodiment of the present invention, an impact sensor 46 is provided on the top of the rectangular steel frame 4 for monitoring the impact force of the debris flow.

[0016] In a preferred embodiment of the present invention, the impact sensor 46 is a triaxial impact sensor; the pressure sensor is a spoke-type sensor.

[0017] In a preferred embodiment of the present invention, the transverse guide rail walls 42 are evenly distributed inside the rectangular steel frame.

[0018] In a preferred embodiment of the present invention, the transparent baffle 6, the bottom surface of the chute, and the sidewalls are made of transparent acrylic sheet.

[0019] In a preferred embodiment of the present invention, a standard grid is drawn on the stacking base plate 9 to record the movement distance, movement speed and stacking status of each group of test materials after they slide down and accumulate.

[0020] Secondly, embodiments of the present invention also provide a physical model test method for the silo effect of ice-rock avalanche debris flow based on cirque topography, implemented using the device described above, characterized in that the method includes the following steps:

[0021] Step S1, Experimental Design: Determine the apex angle of the cirque topography, analyze the controlling factors of the ice-rock debris flow silo effect under the cirque topography, and design an experimental scheme based on the controlling factors.

[0022] Step S2, Equipment Installation: Place high-speed cameras at various locations in the chute, including the initial release area of ​​debris particles, the side erosion area of ​​the funnel, the side of the transverse guide rail wall inside the rectangular steel frame near the center of the chute, and the upper side of the accumulation area; arrange an impact force sensor on the top of the steel frame and a pressure sensor on the lower side of the normal cylinder to monitor the transverse and longitudinal pressure during particle flow; draw a grid on the accumulation bottom plate.

[0023] Step S3, Experiment Preparation: Control the first hydraulic cylinder at the bottom of the hopper to level the hopper, put the prepared simulated debris flow material into the hopper box, and then adjust the second hydraulic cylinder at the bottom of the chute to adjust the slope angle to the target size; according to the size of the apex angle of the funnel area under the simulated cirque topography, make triangular lateral corrosion samples with corresponding lateral corrosion inclination angles on both sides of the chute and place them on the top of the rectangular steel frame, forming a variable angle funnel-shaped lateral corrosion channel between the two triangular lateral corrosion samples; adjust the normal cylinder at the top of the lateral corrosion sample so that the transparent baffle at the bottom of the cylinder is in uniform contact with the upper plane of the lateral corrosion sample, and then apply the same preset overlay pressure to the lateral corrosion samples on both sides of the chute;

[0024] Step S4, Perform the test: Adjust the first hydraulic cylinder at the bottom of the hopper to make the hopper flip upward, release the debris particles in the hopper into the initial release area and flow downward, flow through the funnel area and cause lateral erosion, and finally accumulate on the bottom plate after passing through the flow channel.

[0025] Step S5, Data Collection: Based on high-speed photography and particle velocimetry, acquire the velocity change curves in both the transverse and longitudinal directions at different positions throughout the entire process of debris particle movement; based on the impact force sensor arranged on the top of the steel frame, acquire the pressure change curves in different directions of the funnel area throughout the entire process of debris particle movement; acquire the lateral erosion data under each set of test conditions using a high-speed camera.

[0026] Step S6, Data Analysis: Based on the lateral erosion data of the rate change curve and pressure change curve, analyze the silo effect characteristics and corresponding disaster characteristics of ice-rock debris flow under different funnel zone geometric features, debris flow density and friction properties, as well as the density, friction and strength properties of the lateral erosion material. Analyze the competition mechanism between the silo effect and the dynamic disaster results of ice-rock debris flow under cirque topography.

[0027] The technical solutions provided in the embodiments of the present invention have the following beneficial effects:

[0028] The physical model test device and method for ice-rock debris flow silo effect based on cirque topography provided in this invention can simulate the entire dynamic disaster process of ice-rock debris flow silo effect under three controlling factors in actual cirque topography, mainly including the geometry of the funnel area, the properties of debris flow materials and lateral erosion materials; it can obtain dynamic disaster characteristic data of ice-rock debris flow under different silo effect controlling factors, such as the geometry of the deposition area, deposition distance and deposition scale; it can obtain velocity change curves in both the lateral and longitudinal directions at different positions of the ice-rock debris flow throughout the entire process considering the silo effect; and it can obtain key lateral erosion data to quantify the lateral erosion enhancement effect caused by the silo effect of ice-rock debris flow under cirque topography, including lateral pressure, lateral erosion depth, lateral erosion volume and lateral erosion rate, etc., effectively improving the simulation realism and accuracy of ice-rock debris flow under cirque topography, and improving the accuracy and precision of risk assessment.

[0029] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the physical model test device for the ice and rock avalanche debris flow silo effect based on cirque topography, as described in an embodiment of the present invention.

[0032] Figure 2This is a schematic diagram of the side-etching sample forming a variable-angle funnel-shaped side-etching channel and the overlying normal hydraulic cylinder in an embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the adjustable rectangular steel frame structure in an embodiment of the present invention;

[0034] Figure 4 This is a diagram showing the deployment location of the high-speed camera in an embodiment of the present invention.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1-Hopper, 2-First hydraulic cylinder, 3-Second hydraulic cylinder, 4-Rectangular steel frame, 41-Top of steel frame; 42-Transverse guide rail wall, 44-Transparent inner wall, 45-Padded block, 46-Impact sensor, 5-Side corrosion sample, 6-Transparent baffle, 7-Normal cylinder, 71-Pressure sensor, 8-Guide rail roller, 9-Accumulation base plate, 10-Slide chute, 101-Reaction frame, 102-Side wall, 103-Side rod, 111-First set of cameras, 112-Second set of cameras, 113-Third set of cameras, 114-Fourth set of cameras. Detailed Implementation

[0037] 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 a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can also be combined with each other.

[0038] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, the terms "first," "second," "third," "fourth," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] To address the problems existing in current debris flow simulation devices and methods, this invention provides a physical model test device and method for the silo effect of ice-rock avalanche debris flow based on cirque topography. The trough model test method employs a trough device for lateral erosion specimens that form a funnel-shaped lateral erosion channel with variable angles. The bottom width of the specimen and the outlet width of the funnel area are controlled by a continuously adjustable rectangular steel frame mechanism. A normal hydraulic cylinder is mounted on the lateral erosion specimen, and a spoke-type force sensor is installed at the bottom to apply different normal stresses to control the strength of the lateral erosion specimen. By combining high-speed cameras, triaxial impact force sensors, and particle velocimetry technology based on high-speed camera data at various locations, the experiment explores different funnel geometries, different sliding body materials (density and frictional properties), and... This study investigates the influence of three control factors—density, friction, and strength properties—of lateral erosion specimen materials on the silo effect of debris flows under cirque topography. It quantifies the impact of topographic effects on disaster-causing characteristics, exploring the dynamic response and lateral erosion effect of ice-rock debris flows passing through near-funnel-shaped topography under three control factors: different funnel geometries, sliding materials with varying densities and friction, and lateral erosion specimen materials with different shear strengths. Furthermore, it quantifies the impact of the silo effect on disaster-causing characteristics based on the final depositional features. This research provides experimental technical support for understanding the large-scale, ultra-long-range disaster-causing mechanism of high-altitude, long-distance ice-rock avalanche debris flows, and provides data support for risk assessment and disaster prevention and mitigation of this type of disaster, enabling a better reconstruction and observation of the dynamic response and disaster-causing characteristics of debris flows under the silo effect.

[0040] like Figure 1 As shown, the physical model test device for the ice-rock avalanche debris flow silo effect based on cirque topography includes a hopper 1, a first hydraulic cylinder 2, a second hydraulic cylinder 3, a rectangular steel frame 4, a lateral erosion sample 5, a transparent baffle 6, a normal cylinder 7, a guide rail roller 8, a stacking bottom plate 9, a chute 10, and high-speed cameras installed at each part.

[0041] The chute 10 is placed at a predetermined angle to the ground, connected to the hopper 1 at its higher end and to the stacking base plate 9 at its lower end. A first hydraulic cylinder 2 is installed under the hopper 1 to support the hopper 1, thereby maintaining the preset angle of inclination of the chute 10 connected to the hopper 1. A second hydraulic cylinder 3 is installed on the lower side of the middle part of the chute 10 to provide auxiliary support. The hopper 1 is the loading area of ​​the device, the chute 10 forms the flow area of ​​the device, and the stacking base plate 9 forms the stacking area of ​​the device. The hopper 1 is used to hold simulated ice-rock debris flow material; the first hydraulic cylinder 2 and the second hydraulic cylinder 3 are used together to control the angle between the chute 10 and the horizontal plane to simulate the slope angle of the actual terrain. At the start of the test, the first hydraulic cylinder 2 is adjusted to flip the hopper 1 upward, releasing the simulated debris flow material to flow downward, simulating the start of an actual ice-rock debris flow.

[0042] The chute 10 is divided into an upper flow area and a lower flow area. The upper flow area has solid side walls 102 on both sides, while the lower flow area has suspended side rods 103 on both sides. Rectangular openings are formed on both sides of the lower flow area of ​​the chute 10. The side rods 103 are connected to the side walls 102 and are extensions of the upper edge of the side walls 102. A rectangular steel frame 4 is symmetrically embedded in each of the rectangular openings on both sides.

[0043] like Figure 2 As shown, the height of the rectangular steel frame 4 is lower than the height of the rectangular cutout. The short side of the rectangular steel frame 4 is perpendicular to the side rod 103, and the long side is parallel to the side rod 103. The lower part of the rectangular steel frame 4 extends to the stacking base plate 9. Each rectangular steel frame 4 has several transverse guide rail walls 42 that are perpendicular to the side rod 103 and parallel to the short side. At the intersection of the transverse guide rail wall 42 and the side rod 103, a pad 45 with the same height as the gap is provided, and a guide rail roller 8 is installed on the lower side of the pad 45, so that the transverse guide rail wall 42 can move perpendicularly to the side rod 103 along the guide rail roller 8. The inner wall of the rectangular steel frame 4 is a transparent inner wall 44. Preferably, the transverse guide rail walls 42 are evenly distributed inside the rectangular steel frame 4.

[0044] On the inner side of the upper flow area of ​​the chute 10 and at the top of the rectangular steel frame, symmetrically arranged side-corrosion samples 5 are formed. The side-corrosion samples on both sides form a variable-angle funnel-shaped side-corrosion channel. The side-corrosion sample 5 is a debris-like particle accumulation. The accumulation has the bottom of the chute as the bottom surface and the transparent baffle 6 as the top surface. The cross-section is a right-angled triangle. The two mutually right-angled boundaries are the chute sidewall 102 and the top of the steel frame 41, respectively. The other inclined side is a free side, which participates in the side-corrosion process as the side-corrosion edge. The angle between the side-corrosion edge and the chute sidewall 102 is the side-corrosion inclination angle. The height of the side-corrosion sample 5 is lower than that of the rectangular steel frame 4. The upper side of the side-corrosion sample 5 is covered by a transparent baffle 6 parallel to the bottom of the chute. Two sets of symmetrical normal hydraulic cylinders 7 are arranged on the transparent baffle 6 and directly below the chute reaction frame 101. The shear strength of the side-corrosion sample 5 is changed by adjusting the pressure of the upper normal hydraulic cylinders 7 on both sides. Preferably, each group of normal hydraulic cylinders 7 includes at least two hydraulic rods, arranged longitudinally and parallel to the side 102 of the chute; the first hydraulic rods in each group have the same height, and the second hydraulic rods have the same height, ensuring symmetrical shear strength on both sides. The symmetrically arranged lateral corrosion specimens 5 form a variable-angle funnel-shaped lateral corrosion channel in the middle gap. The side length of the lateral corrosion specimen corresponding to the top 41 of the steel frame is controlled and adjusted by the translation of the rectangular steel frame 4 within the rectangular hollow on the side of the chute, further corresponding to the lateral corrosion inclination angle of the lateral corrosion specimen. The angle variation of the funnel-shaped lateral corrosion channel effectively simulates cirque topography with different apex angles.

[0045] When the apex angle of the funnel area at the entrance of the simulated cirque topography becomes larger and the flow channel narrows, the rectangular steel frame 4 is moved towards the center of the chute. This increases the angle between the lateral corrosion edge of the lateral corrosion sample and the sidewall 102, thus increasing the funnel angle and narrowing the funnel entrance. The lateral corrosion inclination angle of the lateral corrosion sample 5 is determined based on the apex angle of the simulated cirque topography and can be fabricated according to actual conditions during sample preparation.

[0046] like Figure 3 As shown, a pressure sensor 71 is installed at the hydraulic rod of each set of normal cylinders 7. Preferably, the pressure sensor 71 is of the spoke type. A reaction frame 101 is installed at the position of the slide corresponding to the normal cylinder 7, and the top of the cylinder is connected to the slide reaction frame 101. In actual operation, the reaction frame 101, the normal cylinder 7 and the transparent baffle 6 are used to apply an overburden pressure to the lateral corrosion sample 5 to control the shear strength of the lateral corrosion sample 5. The applied force is monitored by the pressure sensor 71 to ensure that the overburden pressure on both sides of the lateral corrosion sample 5 is the same.

[0047] Preferably, an impact force sensor 46 is provided on the top of the rectangular steel frame 4 to monitor the impact force of the debris flow. The impact force sensor 46 is a triaxial impact force sensor.

[0048] During the experiment, the rectangular steel frame 4 was laterally adjusted according to the apex angle of the funnel area in the actual terrain. Adjusting the rectangular steel frame 4 towards the center of the chute simulated a large apex angle and a narrow flow channel, while adjusting it to the sides of the chute simulated a low apex angle and a wide flow channel. Specifically, the adjustment was achieved by using the transverse guide rail wall 42 inside the rectangular steel frame 4 and the guide rail roller 8 at its top to achieve translation, thus performing the lateral adjustment movement. After the experiment, the rectangular steel frame 4 could be adjusted back to the center of the chute and adjusted outwards again before use.

[0049] Preferably, the bottom and sides of the transparent baffle 6 and the chute are all made of transparent acrylic sheets to facilitate observation of the particle state.

[0050] Preferably, a standard grid is drawn on the stacking base plate 9 to record the changes in the movement distance, movement speed, and stacking condition of each group of test materials after they slide down and accumulate.

[0051] Preferably, such as Figure 4 As shown, the cameras include a first group of cameras 111 set in the initial release zone of the debris particles, a second group of cameras 112 set in the funnel side erosion zone, a third group of cameras 113 set in the side of the transverse guide rail wall inside the rectangular steel frame near the center of the chute, and a fourth group of cameras 114 set in the upper side of the accumulation zone. Generally, each group of cameras is set in pairs to collect data more comprehensively.

[0052] Using the aforementioned physical model test apparatus for the silo effect of ice-rock avalanche debris flow based on cirque topography, this embodiment of the invention also provides a test method for the physical model of the silo effect of ice-rock avalanche debris flow based on cirque topography. The specific test steps are as follows:

[0053] Step S1, Experimental Design. Determine the apex angle of the cirque topography, analyze the controlling factors of the silo effect of ice-rock debris flow under the cirque topography, and design an experimental scheme based on the controlling factors.

[0054] The silo effect is influenced by three controlling factors: the geometry of the funnel region, the density and frictional properties of the debris flow, and the density, friction, and strength properties of the lateral erosion material. Based on these factors, experimental schemes were designed. In a specific experiment, three silo effect experimental schemes were designed according to the above three aspects, as shown in Table 1.

[0055] Table 1. Landslide Impact Scraping Test Scheme

[0056]

[0057] As shown in Table 1, in Scheme 1, the silo effect test under different funnel geometries is conducted. Based on the geometric characteristics of the funnel region under the actual cirque topography to be simulated (mainly including the size of the apex angle and the width of the flow channels, apex angles and flow channel widths similar to the actual cirque topography are set), the rectangular steel frame is horizontally adjusted, and lateral erosion samples with predetermined lateral erosion inclination angles are placed on top of the steel frame. In Scheme 2, the silo effect test is conducted under ice-rock debris with different densities and frictions. A mixture of ice particles and rock particles is used to simulate ice-rock debris flow particles. The density and friction of the simulated material are controlled according to the ice particle content (the higher the ice content, the lower the density and the lower the friction) to simulate the ice content in the ice-rock debris flow material. In Scheme 3, the silo effect test is conducted under lateral erosion samples with different shear strengths. The shear strength of the lateral erosion sample is adjusted by the pressure of the normal cylinder at the top of the sample, and multiple sets of overburden pressures are set at equal intervals. Three sets of tests are set for each scheme based on three slope angles.

[0058] Step S2, Equipment Installation. High-speed cameras are placed at various locations in the chute, including the initial release area of ​​debris particles, the lateral erosion area of ​​the funnel, the side of the transverse guide rail inside the rectangular steel frame near the center of the chute, and the upper side of the accumulation area; an impact force sensor is installed on the top of the steel frame, and a pressure sensor is installed on the lower side of the normal cylinder to monitor the transverse and longitudinal pressure during particle flow; a grid is drawn on the accumulation base plate.

[0059] Step S3, Experiment Preparation. The first hydraulic cylinder at the bottom of the hopper is used to level the hopper. The prepared simulated debris flow material is placed into the hopper box. The second hydraulic cylinder at the bottom of the chute is then adjusted to adjust the slope angle to the target size. Based on the size of the apex angle of the funnel area under the simulated cirque topography, triangular lateral corrosion samples with corresponding lateral corrosion inclination angles are made on both sides of the chute and placed on the top of a rectangular steel frame. A variable-angle funnel-shaped lateral corrosion channel is formed between the two triangular lateral corrosion samples. The normal cylinder at the top of the lateral corrosion sample is adjusted so that the transparent baffle at the bottom of the cylinder is in uniform contact with the upper plane of the lateral corrosion sample. Then, the same preset overlay pressure is applied to the lateral corrosion samples on both sides of the chute.

[0060] Step S4, perform the test. Adjust the first hydraulic cylinder at the bottom of the hopper to make the hopper tilt upward, release the debris particles in the hopper into the initial release area and flow downward, flow through the funnel area and cause lateral erosion, and finally accumulate on the bottom plate after passing through the flow channel.

[0061] Step S5, Data Collection. Using high-speed photography and particle velocimetry, acquire velocity variation curves in both the transverse and longitudinal directions at different locations throughout the entire process of debris particle movement; using impact sensors positioned at the top of the steel frame, acquire pressure variation curves in different directions within the funnel region throughout the entire process of debris particle movement; and use a high-speed camera to acquire lateral erosion data for each set of test conditions, including lateral erosion depth, lateral erosion volume, and lateral erosion rate.

[0062] Step S6, Data Analysis. Based on the lateral erosion data from the rate change curve and pressure change curve, analyze the silo effect characteristics and corresponding disaster-causing characteristics of ice-rock debris flow under different funnel zone geometric features, debris flow density and friction properties, as well as the density, friction and strength properties of the lateral erosion material. Also analyze the competition mechanism between the silo effect and the dynamic disaster-causing outcome of ice-rock debris flow under cirque topography, i.e., whether the silo effect forms a dynamic arch to prevent debris flow or causes lateral erosion to expand the disaster scale, while simultaneously exhibiting a blockage effect to enhance debris flow mobility.

[0063] Preferably, this step may also include: summarizing a set of risk assessment methods for ice-rock debris flows under cirque topography, that is, judging the risk of ultra-long-range flow of disasters based on the actual funnel topographic geometry and the physical properties of ice-rock debris flows and lateral erosion materials.

[0064] As can be seen from the above technical solutions, the physical model test device and method for ice-rock debris flow silo effect based on cirque topography provided by the embodiments of the present invention can simulate the three controlling factors of ice-rock debris flow silo effect under actual cirque topography: funnel zone geometry, debris flow material, and lateral erosion material properties; it can obtain dynamic disaster-causing characteristic data of ice-rock debris flow under different silo effect controlling factors, such as deposition zone geometry, deposition distance, and deposition scale; it can obtain velocity change curves in both the transverse and longitudinal directions at different positions during the entire process of ice-rock debris flow considering the silo effect; and it can obtain key lateral erosion data, including lateral pressure, lateral erosion depth, lateral erosion volume, and lateral erosion rate, effectively improving the simulation realism and accuracy of ice-rock debris flow under cirque topography, and improving the accuracy and precision of risk assessment.

[0065] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed, and is not intended to limit the scope of the claimed invention, but merely to illustrate preferred embodiments of the invention. Those skilled in the art should understand that the scope of the invention is not limited to the specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A device for ice-rock avalanche debris flow silo effect physical model test based on cirque topography, characterized in that, The device comprises: A chute is arranged at a predetermined angle with the ground, and is connected with a hopper at a high end and a stacking bottom plate at a low end; a first hydraulic oil cylinder is arranged below the hopper, and a second hydraulic oil cylinder is arranged at the lower side of the middle part of the chute; The chute is divided into an upper flow-through area and a lower flow-through area, wherein the two sides of the upper flow-through area are solid side walls, and the two sides of the lower flow-through area are suspended side rods, and a rectangular hollow is formed at the two sides of the lower flow-through area of the chute; the side rods and the side walls are connected with each other, and the side rods are extensions of the upper edges of the side walls; In the rectangular hollows at the two sides, one rectangular steel frame is symmetrically embedded in each rectangular hollow; the height of the rectangular steel frame is lower than the height of the rectangular hollow, the short side of the rectangular steel frame is perpendicular to the side rod, and the long side is parallel to the side rod; the lower part of the rectangular steel frame extends to the stacking bottom plate; a plurality of horizontal guide rail walls are arranged inside each rectangular steel frame, and the horizontal guide rail walls are perpendicular to the side rod and parallel to the short side; a spacer with the same height as the gap is arranged at the intersection of the horizontal guide rail wall and the side rod, and a guide rail roller is arranged at the lower side of the spacer, so that the horizontal guide rail wall can move horizontally along the guide rail roller and perpendicularly to the side rod; On the inside of the upper flow-through area of the chute and the top of the rectangular steel frame, side erosion samples are symmetrically arranged, and the side erosion samples at the two sides form a variable-angle funnel-shaped side erosion channel; each side erosion sample is a clastic particle accumulation body, the accumulation body has a chute bottom as a bottom surface and a transparent baffle as a top surface, the cross section is in the shape of a right triangle, two mutually perpendicular boundaries are the chute side wall and the top of the steel frame, and the other diagonal side is a free side participating in the side erosion process as a side erosion side; the included angle between the side erosion side and the chute side wall is a side erosion angle; the height of the side erosion sample is lower than that of the rectangular steel frame; the transparent baffle is provided with a normal oil cylinder; the chute is provided with a counterforce frame corresponding to the position of the normal oil cylinder, and the top of the oil cylinder is connected with the counterforce frame.

2. The apparatus of claim 1, wherein, The normal oil cylinder comprises two groups, each group of normal oil cylinder comprises at least two hydraulic rods, and the two hydraulic rods are arranged longitudinally and parallel to the side of the chute; the first hydraulic rod of each group has the same height, and the second hydraulic rod has the same height.

3. The apparatus of claim 1, wherein, A pressure sensor is arranged at the hydraulic rod of the normal oil cylinder, and is used to control the shear strength of the side erosion sample through the counterforce frame, the normal oil cylinder and the transparent baffle.

4. The apparatus of claim 3, wherein, An impact force sensor is arranged at the top of the rectangular steel frame, and is used to monitor the impact force of the clastic flow.

5. The apparatus of claim 4, wherein, The impact force sensor is a three-way impact force sensor; the pressure sensor is a spoke sensor.

6. The apparatus of claim 1 or 2, wherein, The horizontal guide rail walls are distributed at equal intervals inside the rectangular steel frame.

7. The apparatus of claim 1, wherein, The bottom surface and the side wall of the chute and the transparent baffle are made of transparent acrylic plates.

8. The apparatus of claim 1, wherein, A standard grid is drawn on the stacking bottom plate to record the movement distance, movement speed and stacking condition of each group of test materials after sliding and stacking.

9. A physical model test method for the cornice topography based rock avalanche debris flow silo effect, which is implemented by using the device according to any one of claims 1-8, characterized in that, The method comprises the following steps: Step S1, test scheme design: determining the top angle of the cirque terrain, analyzing the control factors of the silo effect of the ice-rock debris flow under the cirque terrain, and designing a test scheme according to the control factors; Step S2, equipment installation: high-speed cameras are placed at each part of the chute, including the initial release area of the debris particles, the side erosion area of the funnel, the wall side of the horizontal guide rail inside the rectangular steel frame, the center side of the chute, and the upper side of the accumulation area; impact force sensors are arranged on the top of the steel frame, and pressure sensors are arranged on the lower side of the normal oil cylinder to monitor the transverse and longitudinal pressures during the flow of the particles; Draw a grid on the accumulation bottom plate; Step S3, test preparation: the first hydraulic oil cylinder at the bottom of the hopper is controlled to flatten the hopper, the prepared simulated debris flow material is placed in the hopper box, and the second hydraulic oil cylinder at the bottom of the chute is adjusted to adjust the slope angle to the target size; according to the size of the top angle of the funnel area under the simulated ice gully terrain, triangular side erosion samples with corresponding side erosion angles are respectively made on both sides of the chute and placed on the top of the rectangular steel frame, and a variable-angle funnel-shaped side erosion channel is formed between the two triangular side erosion samples; the normal oil cylinder on the upper part of the side erosion sample is adjusted so that the transparent baffle at the bottom of the oil cylinder is in uniform contact with the upper plane of the side erosion sample, and then the same preset overburden pressure is applied to the side erosion samples on both sides of the chute; Step S4, execute the test: adjust the first hydraulic oil cylinder at the bottom of the hopper to make the hopper turn upward, release the debris particles in the hopper into the initial release area and flow downward, flow through the funnel area and undergo side erosion, and finally accumulate on the accumulation bottom plate through the flow channel; Step S5, data collection: according to high-speed photography imaging and particle velocity measurement technology, the velocity variation curves in the transverse and longitudinal directions at different positions in the whole process of debris particle movement are obtained; according to the impact force sensors arranged on the top of the steel frame, the pressure variation curves in different directions in the whole process of debris particle movement are obtained; according to the high-speed cameras, the side erosion data under each group of test conditions are obtained; Step S6, data analysis: according to the side erosion data of the velocity variation curves and the pressure variation curves, the characteristics of the ice-rock debris flow silo effect and the corresponding disaster characteristics under different funnel area geometric characteristics, debris flow density and friction properties, as well as the density, friction and strength properties of the side erosion material are analyzed, and the competition mechanism of the silo effect under the ice gully terrain on the dynamic disaster results of the ice-rock debris flow is analyzed.

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