A method for testing variable sliding speed local submerged landslide surge dam surface hydrodynamic pressure

Abstract

The application discloses a kind of variable sliding speed local submergence type landslide surge dam face hydrodynamic pressure test method, comprising the following steps: (1) establish the physical model of landslide surge in line with topographic features;(2) use 3D printing to make sliding surface of different materials;(3) dam wave height tester and hydrodynamic pressure sensor are arranged at dam face;(4) carry out landslide surge physical model test under different sliding speeds;(5) data analysis is carried out to the maximum climbing of surge and the maximum hydrodynamic pressure distribution on dam face under different sliding speeds, the interrelationship of surge climbing and dam face hydrodynamic pressure distribution is obtained, and the maximum hydrodynamic pressure distribution under different surge climbing of dam face can be obtained using the relationship. The application solves the problem that the sliding speed of local submergence landslide cannot be adjusted and the maximum hydrodynamic pressure distribution on dam face is difficult to obtain in engineering, and provides an effective way for accurately evaluating the impact of landslide surge disaster.

Description

Technical Field

[0001] This invention relates to landslide surges in the field of geotechnical engineering, and more particularly to a method for testing the dynamic water pressure on the face of a landslide surge dam with variable sliding speed and local submersion. Background Technology

[0002] Localized submersion landslides are the most common type of landslide in reservoir areas. These landslides often occur after the reservoir is filled with water, where previously exposed slopes are submerged. Under the influence of water, the mechanical parameters of the landslide body and sliding surface decrease significantly, reducing the effective stress within the landslide body and leading to a landslide. Landslide instability will generate more severe secondary disasters from landslide surges, seriously threatening the lives and property of people along the reservoir and the stable operation of water conservancy projects.

[0003] In locally submerged landslides, the landslide has already interacted with the water body at the initiation stage, and the surge is formed instantly upon the landslide's instability and sliding. This characteristic differs significantly from the surge formed by a landslide impacting water at a certain speed. For landslides on water, control focuses on controlling the landslide's entry velocity into the water, without needing to consider the landslide's movement on the water. Therefore, applying different initial velocities to the landslide using dynamic control devices facilitates systematic research on the surge characteristics under different entry velocities. However, locally submerged landslides require consideration of the entire instability and sliding process. The landslide's sliding mode, range, and volume are usually determined during the geological survey stage, while the landslide velocity can only be predicted through calculation. Therefore, studies of landslide surges at different velocities are needed to define the degree of surge influence, but conducting such studies on locally submerged landslide surges at different velocities presents considerable challenges.

[0004] Landslide surges exert enormous hydrodynamic pressure on dams, significantly impacting their gates and dam face. The Malpasse Arch Dam collapse in 1959, caused by heavy rainfall leading to a sharp rise in reservoir water levels and the inability of the gates to open due to excessive water pressure, resulted in the dam's instantaneous collapse. This major engineering failure demonstrates the crucial importance of accurate assessment of landslide surges, especially in the reservoir area near the dam, and the magnitude and distribution of the water pressure exerted by these surges on the dam and gates for engineering safety.

[0005] Currently, various numerical methods are used to calculate landslide surge height and dam run-up, but very few methods are used to calculate the hydrodynamic pressure on the dam face. Model testing is an important and reliable means of directly obtaining hydrodynamic pressure on the dam face. How to transform the limited experimental data on hydrodynamic pressure on the dam face into a reference and basis for numerical calculation, and then accurately obtain the distribution characteristics of hydrodynamic pressure on the dam face from the wave height or run-up obtained by numerical calculation, is an important problem in landslide surges in reservoir-dam areas. Summary of the Invention

[0006] Objective: To address the problems in landslide surge calculations, such as the inability to adjust the sliding velocity of locally submerged landslides and the difficulty in obtaining the maximum hydrodynamic pressure distribution on the dam face through numerical calculations, this invention proposes a method for testing the hydrodynamic pressure on the dam face of locally submerged landslide surges with variable sliding velocity. This method involves replacing the sliding surface in the surge physical model with 3D-printed sliding surfaces of different friction coefficients, thus adjusting the sliding velocity of the landslide. Data analysis of the hydrodynamic pressure on the dam face at different run-up heights is performed to determine the relationship between run-up height and maximum hydrodynamic pressure. Using this formula, the maximum hydrodynamic pressure distribution on the dam face is obtained through the run-up height. This method solves the problems of difficulty in changing the landslide velocity and the difficulty in obtaining the maximum hydrodynamic pressure distribution on the dam face through numerical calculations in the study of locally submerged landslide surges, providing an effective approach for accurately assessing the impact of landslide surges.

[0007] Technical solution: The present invention provides a method for testing the dynamic water pressure on the face of a variable-speed, partially submerged landslide surge dam, comprising the following steps:

[0008] (1) Establish a physical model of landslide surge that conforms to the terrain characteristics; the process is as follows:

[0009] (1.1) Establish landslide surge channels based on topographic contour lines;

[0010] (1.2) Establish the sliding surface of the landslide wave physical model at the landslide body in the landslide wave channel;

[0011] (1.3) Construct the dam in the landslide surge physical model;

[0012] (2) Use 3D printing to create sliding surfaces of materials with different coefficients of friction;

[0013] (3) Install wave height testers at the dam face to measure surge run-up, and install dynamic water pressure sensors at the dam face to measure dynamic water pressure;

[0014] (4) Conduct physical model tests of landslide surges at different sliding velocities; the process is as follows:

[0015] (4.1) Place the 3D-printed sliding surface at the sliding surface of the landslide surge physical model;

[0016] (4.2) Lay the landslide mass on the 3D-printed sliding surface, place the baffle at the landslide outlet, and connect one end of the baffle to a winch. Install hydrodynamic pressure sensors on the dam and impound water in the landslide surge channel;

[0017] (4.3) Place velocity sensors inside the landslide body to monitor the landslide velocity;

[0018] (4.4) After the landslide surge channel is impounded, the landslide body is released by a winch and baffle and the sliding speed of the landslide body is measured to obtain the surge dam climb height and dam surface dynamic water pressure at the sliding speed.

[0019] (4.5) Replace the 3D printed sliding surface with different friction coefficients and repeat steps (4.1) to (4.4) to obtain the rise of the swell on the dam surface at different sliding speeds and the maximum hydrodynamic pressure at different water depths on the dam surface.

[0020] (4.6) Repeat steps (4.1) to (4.5) to complete multiple sets of landslide surge tests under different friction coefficients;

[0021] (5) Analyze the data of the maximum run-up of the surge on the dam surface and the maximum hydrodynamic pressure at different water depths under different slip speeds, determine the relationship between the surge run-up and the maximum hydrodynamic pressure at different water depths on the dam surface, and use this relationship to calculate the maximum hydrodynamic pressure at different water depths on the dam surface under a given run-up.

[0022] In step (1.2), after determining the shape of the river channel at the landslide body, the sliding surface of the landslide body physical model is established at the landslide body in the landslide surge channel based on the characteristics of the landslide sliding surface revealed by the geological profile of the landslide body.

[0023] Step (2) includes the following steps:

[0024] (2.1) Based on the characteristics of the landslide surface revealed by the geological profile of the landslide body, the shape of the landslide surface is obtained;

[0025] (2.2) Use materials with different friction coefficients to 3D print the sliding surface of the landslide body to obtain sliding surfaces with different friction coefficients that have the same shape as the sliding surface in the landslide surge physical model.

[0026] The method for setting up the climbing measurement points and hydrodynamic pressure measurement points in step (3) is as follows:

[0027] (3.1) Set up wave height testers along the dam face at the central water level line to measure the surge run-up;

[0028] (3.2) Dynamic water pressure sensors are installed at the center of different elevations on the dam surface to measure dynamic water pressure.

[0029] In step (4.2), the dynamic water pressure sensors are densely arranged at the water level line to obtain detailed dynamic water pressure changes.

[0030] In step (4.2), a steering beam is fixed at the top of the baffle, and one end of the steering beam is connected to the column through a bracket.

[0031] In step (4.4), the process of releasing the landslide body is as follows: the winch is turned on to lift the baffle, and the landslide body slides down under gravity.

[0032] In step (5), the steps to obtain the relationship between wave run-up and the hydrodynamic pressure distribution on the dam face are as follows:

[0033] (5.1) Plot the maximum hydrodynamic pressure distribution curves at different surge dam surface run-up heights and different water depths at the dam surface;

[0034] (5.2) Data analysis was conducted on the hydrodynamic pressure on the dam face under different wave run-up heights to determine the relationship between wave run-up height and maximum hydrodynamic pressure at different water depths on the dam face. The maximum hydrodynamic pressure is related to both dam run-up height and river depth.

[0035] P 水位下 =ah+(b+ce) dh )e -x / 40h

[0036] In the formula, P 水位下 Let be the dynamic water pressure (kPa), h be the maximum run-up of the wave dam surface (m), x be the water depth (m), and a, b, c, and d be fitting constants.

[0037] By fitting the experimental results using this relationship, the formula for calculating the maximum hydrodynamic pressure at different water depths on the dam surface can be obtained.

[0038] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0039] (1) This invention uses 3D printing to create sliding surfaces with different friction coefficients. The landslide body is fixed on the sliding surface by a baffle. Then, a winch is used to pull up the baffle to release the landslide body, thereby completing the local submerged landslide surge test.

[0040] (2) By replacing the sliding surface in the wave physics model with 3D-printed sliding surfaces of different friction coefficients, the sliding speed of the sliding body was adjusted; data analysis was performed on the hydrodynamic pressure on the dam surface at different run-up heights to determine the relationship between run-up height and maximum hydrodynamic pressure. It was found that this relationship conforms to a negative exponential function, and the maximum hydrodynamic pressure is related to the run-up height of the dam surface and the river depth. By fitting the experimental results with this relationship, the calculation formula for the maximum hydrodynamic pressure at different water depths on the dam surface can be obtained.

[0041] (3) This invention uses numerical calculation of landslide surge dam surface climb height to obtain the maximum dynamic water pressure distribution on the dam surface. This method solves the problem that the sliding velocity of locally submerged landslides cannot be adjusted and that numerical calculation is difficult to obtain the maximum dynamic water pressure distribution on the dam surface, providing an effective way to accurately assess the impact of landslide surge. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the physical model structure of the variable slip velocity locally submerged landslide surge wave of the present invention;

[0043] Figure 2 This is a layout diagram of the dynamic water pressure sensor in this invention;

[0044] Figure 3This is a schematic diagram of a sliding surface made using 3D printing and placed on the sliding surface of a landslide body, according to the present invention.

[0045] Figure 4 This is a diagram showing the completion of water storage after the landslide body has accumulated, according to the present invention.

[0046] Figure 5 This is a diagram showing the distribution of maximum hydrodynamic pressure at different climbing heights in this invention;

[0047] Figure 6 This is a graph showing the negative exponential function formula for the relationship between climb height and maximum hydrodynamic pressure as determined in this invention. Detailed Implementation

[0048] like Figure 1 As shown, the process of constructing a physical model of a variable-speed, locally submerged landslide surge wave in this invention is as follows: A landslide surge wave channel 1 is established using actual topographic contour lines. Considering both the topographic contour lines and the geological profile of the landslide body, after determining the shape of the channel 1 at the landslide body, a sliding surface 2 of the landslide body is established at the landslide body location based on the characteristics of the landslide sliding surface revealed by the geological profile. A dam model 3 is established at the corresponding location according to the actual shape of the dam. A winch 4 is placed on the opposite bank of the landslide body, and the winch 4 is secured to a baffle 9 via a steel wire rope 7 that passes over a steering beam 8. The baffle 9 is placed at the shear outlet of the landslide body to prevent the landslide body 14 from sliding down and to fix the landslide body 14 to the sliding surface 13. The steering beam 8 is welded to a support 6, which spans over the top of the model and is fixed to a column 5. The height of the column 5 is higher than the maximum height of the physical model to support the support 6. The support 6 is fixed to the beam and spans over the model, and the steering beam 8 is welded to it. The wave-dissipating pool 10 and the wave-dissipating sponge 11 are used to eliminate the swell propagating upstream and reduce its impact on the experimental results. 12 is the location for the wave height meter at the dam, used to monitor the rise of the swell on the dam surface.

[0049] The dam dynamic water pressure sensor is deployed on the dam, and the arrangement of the dam dynamic water pressure sensor in this invention is as follows: Figure 2 As shown, before the river was impounded, the dynamic water pressure changed drastically at the impoundment level, so the sensors were densely arranged at the impoundment level.

[0050] In step (4), the process of the variable sliding speed local submerged landslide surge hydrodynamic pressure test and testing method of the present invention is as follows:

[0051] (1) As Figure 3 As shown, the sliding surface 13, which is made by 3D printing, is laid on the sliding surface 2 of the physical model.

[0052] (2) Figure 4As shown, after the 3D-printed sliding surface 13 is laid, the landslide body 14 is piled on the 3D-printed sliding surface 13 and water is added. Because the baffle 9 is relatively thin, it is submerged underwater after water is added.

[0053] (3) After the water surface stabilizes, start the winch 4 to lift the baffle 9. The landslide body 14 loses the support of the baffle 9 and slides into the water, stirring up waves. Figure 5 This section describes the surge height at the dam face and the corresponding maximum hydrodynamic pressure distribution obtained from different sliding surfaces. Figure 5 The results show that the maximum hydrodynamic pressure increases with the rise of the surge wave on the dam face, and gradually decreases with the increase of water depth.

[0054] (4) Figure 6 To fit the maximum hydrodynamic pressure at different depths and different climb elevations using a negative exponential function, the fitting formula used is as follows:

[0055] P 水位下 =ah+(b+ce) dh )e -x / 40h

[0056] In the formula, P 水位下 Let be the dynamic water pressure (kPa), h be the maximum run-up of the wave dam surface (m), x be the water depth (m), and a, b, c, and d be fitting constants.

[0057] The final formula relating climb height and maximum hydrodynamic pressure is as follows:

[0058] P = 2.88h + (34.48 + 0.028e) 0.57h )e -x / 40h

[0059] from Figure 6 It can be seen that the formula has a high fitting coefficient, thus it can better predict the distribution of hydrodynamic pressure on the dam surface under different surge heights.

Claims

1. A method for testing the hydrodynamic pressure on the face of a wave dam in a locally submerged landslide with variable sliding velocity, characterized in that: Includes the following steps: (1) Establish a physical model of landslide surge that conforms to the terrain characteristics. The process is as follows: (1.1) Establish landslide surge channels based on topographic contour lines (1); (1.2) After determining the shape of the river channel at the landslide body, based on the characteristics of the landslide sliding surface revealed by the geological profile of the landslide body, establish the sliding surface (2) of the landslide wave physical model at the landslide body in the landslide wave channel (1). (1.3) Establish the dam in the landslide surge physical model (3); (2) Using 3D printing to create sliding surfaces of materials with different coefficients of friction; the process is as follows: (2.1) Based on the characteristics of the landslide surface revealed by the geological profile of the landslide body, obtain the shape of the landslide surface; (2.2) Use materials with different friction coefficients to 3D print the sliding surface of the landslide body to obtain sliding surfaces with different friction coefficients that have the same shape as the sliding surface in the physical model of the landslide surge; (3) Set up wave height testers along the dam surface at the central water level line of the dam surface to measure the surge rise, and set up dynamic water pressure sensors at the center of different elevations of the dam surface to measure dynamic water pressure. (4) Conduct physical model tests of landslide surges at different sliding velocities. The process is as follows: (4.1) Place the 3D-printed sliding surface at the sliding surface (2) of the landslide surge physical model; (4.2) Lay the landslide body (14) on the 3D printed sliding surface (13), tie the winch (4) to the upper end of the baffle (9), fix the steering beam (8) above the baffle (9), place the baffle (9) at the landslide body outlet, install dynamic water pressure sensors on the dam and store water in the landslide surge channel (1); (4.3) Place a velocity sensor inside the landslide body (14) to monitor the landslide velocity; (4.4) After the water storage of the landslide surge channel is completed, the winch (4) is turned on to lift the baffle (9), and the landslide body (14) is released through the winch and the baffle. The sliding speed of the landslide body (14) is measured, and the rise of the surge dam and the dynamic water pressure on the dam surface under the sliding speed are obtained. (4.5) Replace the 3D printed sliding surface with different friction coefficients and repeat steps (4.1) to (4.4) to obtain the rise of the swell on the dam surface at different sliding speeds and the maximum hydrodynamic pressure at different water depths on the dam surface. (4.6) Repeat steps (4.1) to (4.5) to complete multiple sets of landslide surge tests under different friction coefficients; (5) Analyze the data of the maximum run-up of the surge on the dam surface under different sliding velocities and the maximum hydrodynamic pressure at different water depths to determine the relationship between the surge run-up and the maximum hydrodynamic pressure at different water depths on the dam surface. Using the relationship, the maximum hydrodynamic pressure at different water depths on the dam surface can be calculated at a given run-up. The process is as follows: (5.1) Plot the maximum hydrodynamic pressure distribution curves at different wave run-up heights and different water depths on the dam surface; (5.2) Data analysis was conducted on the hydrodynamic pressure on the dam face under different wave run-up heights to determine the relationship between wave run-up height and maximum hydrodynamic pressure at different water depths on the dam face: O 水位下 =aℎ+(b+c𝑒 dℎ )𝑒 -𝑥 / 40ℎ In the formula, 𝑃 水位下 denoted as dynamic water pressure (kPa), h as maximum run-up of the wave dam surface (m), x as water depth (m), and a, b, c, and d as fitting constants; By fitting the experimental results using this relationship, we can obtain the calculation formula for the maximum hydrodynamic pressure at different water depths on the dam surface.

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