Experimental and field measurement of impact force of debris flow cross section

Abstract

This invention discloses an experimental and field measurement method for the cross-sectional impact force of debris flows. In the experimental measurement of cross-sectional impact force, the method utilizes the experimental system and data to construct an empirical Green's function for the cross-section through convolution inversion. Then, it obtains the vertical ground motion signal at any cross-section, enabling the measurement of the vertical impact force of the solid phase at that location. Furthermore, by introducing a flow depth parameter, it also enables the measurement of the vertical impact force of the liquid phase on the cross-section. In the field measurement of cross-sectional impact force, based on experimental measurements, it solves the problem of simulating and identifying debris flows in the field, enabling the measurement of the vertical impact force of the solid and liquid phases on the channel cross-section. Optimized schemes address signal compensation and the problem of calculating the characteristic particle size using the power spectral density (PSD) of the signal. This invention solves the problem of directly inverting and measuring the impact force of debris flows using ground motion signals, and the problem of separately measuring the vertical impact force of the solid and liquid phases, enabling more effective use of seismic monitoring network data in the field of mountain disasters.

Description

Technical Field

[0001] This invention relates to the field of debris flow motion characteristic measurement, and in particular to experimental and field measurement methods for the impact force of debris flow cross sections. Background Technology

[0002] The scientific description and measurement of debris flow impact characteristics is one of the most important issues in debris flow research and prevention. Debris flow impact force measurement technology is a fundamental aspect of debris flow research and prevention technologies. A fundamental question in debris flow impact measurement is which technical means to employ. Utilizing signals to reflect the debris flow impact motion, and then interpreting and inverting these signals to calculate motion characteristic parameters, is currently a relatively ideal debris flow impact measurement scheme. In this scheme, the specific selection of the signal type becomes crucial. Seismic signals generated by debris flow impacting the bottom of the channel contain information about the debris flow motion process and are therefore a useful signal type for interpreting debris flow impact characteristics.

[0003] The existing technology "Research on the Generation Mechanism and Quantitative Analysis of Ground Motion Signals during Debris Flow Movement" (Zhou Kailai, Southwest Jiaotong University, 2023) analyzes the time-domain, frequency-domain, and time-spectrum characteristics of the bottom impact force and ground motion signals during debris flow movement based on an indoor flume model, as well as the quantitative relationship between bottom wave dynamics and ground motion signals. However, its sensors are installed at the bottom, making them susceptible to damage in real debris flow environments, thus limiting their field application. The existing technology "Research on the Dynamic Mechanism and Early Warning of Outburst Debris Flow Based on Ground Motion Monitoring—Taking the Bailongjiang River Basin as an Example" (Yang Yunpeng, Lanzhou University, 2024) discloses a method for debris flow monitoring, early warning, and quantitative inversion of dynamic parameters based on ground motion signals, constructed using indoor and outdoor physical model experiments and long-term field monitoring data. However, its published peak impact force prediction formula is constructed using mass and momentum conservation equations, not based on the analysis and inversion of ground motion signals. While these technologies provide some scientific information about the relationship between debris flows and ground motion signals, they do not offer practical technical solutions for measuring debris flow impact using ground motion signal acquisition and analysis.

[0004] Advanced issues in using signal analysis and inversion to calculate debris flow impact motion include: Problem 1: The directly acquired motion signals are generated by the debris fluid itself. However, in debris flow research, many problems require the analytical framework to be established on the debris fluid cross-section. Therefore, this type of measurement scheme also needs to solve the technical problem of effectively separating the "surface signal" from the acquired "volume signal" so that the technology can be applied to the characteristics of any cross-section of the debris fluid. Problem 2: In theoretical analysis, debris fluid is generally generalized as a two-phase fluid. How to distinguish and quantify the impact characteristics of the solid and liquid phases of debris flow, especially considering the practical needs in prevention and control engineering design, requires debris flow impact measurement technology to be able to measure solid-phase impact and liquid-phase impact separately. These two problems have also not been solved by existing technologies. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of existing technologies, this invention provides a method for experimental and field measurement of the impact force of mud and rock fluid cross sections.

[0006] The technical solution adopted in this invention is a method for experimental and field measurement of the impact force of mud and rock fluid cross sections, which includes:

[0007] A debris flow flume experimental system was constructed, and a measurement section M was arranged parallel to the flume axis. Section M intersected the bottom of the flume at line a. Sensors were arranged on line a, including a normal stress sensor and a ground vibration sensor.

[0008] A flume simulation experiment was conducted to collect combined signals [F] of the debris flow at section M under different simulation conditions. dm (t),U m [(t)],F dm (t) and U m (t) represent the vertical impact force signal and vertical ground motion signal of the debris flow solid phase on the same cross section M, respectively; the empirical Green's function G(t) of the cross section is constructed by convolution inversion using experimental data to characterize the F on cross section M. dm (t) and U m (t) Relationship between them;

[0009] An arbitrary monitoring section A1, parallel to the measurement section M, is arranged within the debris flow flume. A debris flow flume simulation experiment is conducted, and the vertical ground motion signal U1(t) of the debris flow at section A1 is collected. The vertical impact force of the solid phase of the debris flow at the arbitrary monitoring section A1 is calculated according to the model of equation (1).

[0010] F d1 (t)=U1(t)*G -1 (t) (1)

[0011] In the formula, F d1(t) represents the vertical impact force of the debris flow solid phase at monitoring section A1, U1(t) represents the vertical ground motion signal at monitoring section A1, and G -1 (t) represents the deconvolution part of the empirical Green's function for the cross section, and * represents the convolution calculation.

[0012] Furthermore, the method also includes measuring the vertical impact force of the liquid phase on any monitoring section A1;

[0013] The debris flow flume experimental system has a flow depth h arranged on cross section M. m The measuring instrument includes an online pore water pressure sensor mounted on top.

[0014] A flume simulation experiment was conducted to collect the vertical water pressure F of the debris flow at section M under different simulation conditions. fm (t), using experimental data to construct F expressed according to equation (2) fm (t) model,

[0015] F fm (t)=f(ρ m ,h m ,s m (2)

[0016] In the formula, F fm (t), h m These are the vertical water pressure and debris flow depth at section M, respectively. m To simulate the density of debris flow in the experiment, D is the characteristic parameter of the particle size distribution of debris flow, s m The sensing area of ​​the pore water pressure sensor;

[0017] A debris flow flume simulation experiment was conducted, and the debris flow depth at monitoring section A1 was collected. The vertical impact force F of the debris flow liquid phase at section A1 was calculated using the constructed model (2). f1 (t).

[0018] Furthermore, the D is D 94 The model expression function of equation (2) is equation (2.1).

[0019] F fm (t)=ρ m gh m s m (D 94 ) 0.04 (2.1)

[0020] In the formula, g is the gravitational acceleration constant.

[0021] Furthermore, an empirical Green's function G(t) for the cross-section was constructed using the experimental measurement method of impact force on mud and rock fluid cross-sections.

[0022] A debris flow ground motion signal monitoring system was set up at the gully site, including: setting up a monitoring section A2 perpendicular to the gully direction, with section A2 intersecting the gully bed centerline b at point O, and placing surface vibration sensors at point P on one side of the gully bank extension line of section A2.

[0023] When the debris flow passes through, the vertical ground motion signal U2(t) of the debris flow at point P is collected, and the vertical ground motion signal X2 generated at section A2 is extracted according to equation (3).

[0024]

[0025] In the formula, H is the calculation parameter, r is the straight-line distance between point O and point P, L is the length of the debris flow channel, and n is an empirical value, which is 5, 4, and 3 respectively for small, medium, and large debris flows.

[0026] Substituting X2=U1(t) into the model of Equation 1 constructed in claim 1, the vertical impact force F of the debris flow solid phase at section A2 is calculated. D2 (t).

[0027] Furthermore, a rockfall impact test was conducted at point O on the surface of the gully bed. Vertical ground motion signals U at points O and P were collected using a ground motion sensor under the same rockfall impact test conditions. 21 (t), U 22 (t), analyze U 21 (t) and U 22 (t), determine the vertical seismic signal absorption attenuation factor Q of section A2;

[0028] When the debris flow passes through, the vertical ground motion signal U2(t) of the debris flow at point P is collected. The vertical ground motion recovery signal U′2(t) of the debris flow is obtained by compensating and recovering U2(t) using the absorption attenuation factor Q.

[0029] Substitute U′2(t)=U1(t) into equation (3) to calculate and determine X2.

[0030] Furthermore, U2(t) is compensated and restored according to equation (4).

[0031]

[0032] In the formula, J and K are calculation parameters, and U 23 (t,f) are intermediate values ​​for calculation, σ is the stability control factor, e is the natural constant, f is the frequency of U2(t), ω0 is the reference angular velocity of U2(t) at 1Hz, ω0=2π, ω is the angular velocity of U2(t), f s Let be the centroid frequency of U2(t).

[0033] Furthermore, the debris flow ground motion signal monitoring system also includes a debris flow depth measuring instrument at section A2, which collects the debris flow depth h at section A2 and calculates the vertical impact force F of the debris flow liquid phase at section A2 according to the model of equation (2). f2 (t), where ρ m Take values ​​for debris flow density ρ and h m The values ​​of h and D are determined based on on-site observations.

[0034] Furthermore, the vertical impact force F of the debris flow liquid phase at section A2 is calculated using equations (2.1) and (5). f2 (t), where D 94 Based on on-site observations,

[0035] s m =W×1m (5)

[0036] In the formula, W is the average width of the channel.

[0037] Furthermore, the D 94 The power spectral density (PSD2) of signal U2(t) is determined by inversion calculation, and the following scheme is implemented:

[0038] The debris flow ground motion signal monitoring system also includes a debris flow velocity measuring instrument at section A2, which collects the signal U2(t), debris flow velocity u, and flow depth h at section A2, calculates the power spectral density PSD2 of the signal U2(t), and constructs D according to equation (6). 94 Inversion calculation model,

[0039] D 94 =f(PSD2,u,r,c,ξ,v) c ,r,f) (6)

[0040] In the formula, u is the debris flow velocity at section A2, c is the width of section A2, ξ is the source depth correction parameter, with a value of 0.4, and v c Let f be the propagation speed of the Rayleigh wave phase of U2(t) at 1 Hz, and f be the frequency of U2(t).

[0041] Furthermore, the model in equation (6) is expressed as equation (6.1).

[0042]

[0043] In the formula, e is the natural constant, and R and B are calculation parameters.

[0044] Beneficial effects: This invention proposes a method for experimental and field measurement of the impact force of debris flow cross sections. (1) Specifically, this invention provides a technical concept of using seismic signals to reflect the impact motion of debris flow, and then realizing the measurement of debris flow impact through signal analysis and inversion. This technical concept establishes a scientific scheme between the seismic signals generated by the impact of debris flow on the ground and the quantification of debris flow impact characteristics, extending the law research of existing technologies to a practical and specific technical scheme, making up for the deficiency of existing technologies in directly measuring the solid-liquid two-phase impact force of debris flow, and expanding debris flow measurement technology. (2) Since the seismic signals are transmitted by the stratum rock mass, the instruments can only collect signals generated by the entire debris flow, which limits the utilization of signal data in the study of debris flow impact problems. This invention solves the technical problem of extracting and separating the seismic signals generated at a specified cross section of the debris flow from the debris flow signal through a measurement approach that combines indoor water tank experiments with field observation systems, that is, effectively separating the "surface signal" from the "volume signal". The solution to this problem enables debris flow research based on seismic signal analysis to establish a theoretical analysis framework on the debris flow cross section, which is conducive to applying the corresponding results in the field of fluid to the field of debris flow research and technology development. (3) The technical solution of this invention utilizes the characteristics of debris flow seismic signals, which are mainly generated by particles impacting the bottom of the channel during the debris flow movement. Through theoretical analysis of flume experiments and the application of field measurement technology, the solid phase impact force is calculated using seismic signals. Combined with the debris flow movement characteristics calculated by seismic signals, the liquid phase impact force is calculated, which solves the technical problem of separately measuring the impact force generated by the solid phase component and the liquid phase component in debris flow impact measurement. (4) The technical concept of this invention introduces seismic signal analysis methods into debris flow problem research, solves the most basic problem of solid-liquid two-phase impact force measurement, and enables the data of the earthquake monitoring network to be used more effectively in the field of mountain disasters, enhancing the social and environmental benefits of the integrated utilization of public service products. Attached Figure Description

[0045] Figure 1 This is a flowchart of the method of the present invention;

[0046] Figure 2 This is a partial schematic diagram of the structure and cross-section M of the mudflow flume experimental system of the present invention;

[0047] Figure 3 This is a graph of the empirical Green's function G(t) constructed in this invention;

[0048] Figure 4 This is a schematic diagram of the structure of the gully debris flow ground motion signal monitoring system of the present invention;

[0049] Figure 5 This is a graph of the vertical ground motion signal U2(t) of debris flow according to the present invention;

[0050] Figure 6 This invention relates to the signal U2′(t) curve after U2(t) is recovered by absorption attenuation factor Q compensation;

[0051] Figure 7 This is a schematic diagram of the vertical seismic motion signal X2 of debris flow at section A2 extracted by the present invention;

[0052] Figure 8 The present invention relates to the solid phase impact force F at section A2 of the mud and rock fluid. d2 (t) curve;

[0053] Figure 9 The vertical impact force F of the liquid phase at section A2 of the mud-rock fluid in this invention is... f2 (t) curve.

[0054] The numbers in the attached diagram are labeled as follows:

[0055] 1. Water tank; 2. Sensor; 3. High-speed camera device. Detailed Implementation

[0056] It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. The following describes the application in further detail with reference to the accompanying drawings and specific embodiments.

[0057] like Figure 1 As shown, the experimental and field measurement method for the impact force of debris fluid cross-section is as follows:

[0058] A debris flow flume experimental system was constructed, and a measurement section M was arranged parallel to the flume axis. Section M intersected the bottom of the flume at line a. Sensors were arranged on line a, including a normal stress sensor and a ground vibration sensor.

[0059] A flume simulation experiment was conducted to collect combined signals [F] of the debris flow at section M under different simulation conditions. dm (t),U m [(t)],F dm (t) and U m (t) represent the vertical impact force signal and vertical ground motion signal of the debris flow solid phase on the same cross section M, respectively; the empirical Green's function G(t) of the cross section is constructed by convolution inversion using experimental data to characterize the F on cross section M. dm (t) and U m (t) Relationship between them;

[0060] An arbitrary monitoring section A1, parallel to the measurement section M, is arranged within the debris flow flume. A debris flow flume simulation experiment is conducted, and the vertical ground motion signal U1(t) of the debris flow at section A1 is collected. The vertical impact force of the solid phase of the debris flow at the arbitrary monitoring section A1 is calculated according to the model of equation (1).

[0061] F d1 (t)=U1(t)*G -1 (t) (1)

[0062] In the formula, F d1 (t) represents the vertical impact force of the debris flow solid phase at monitoring section A1, U1(t) represents the vertical ground motion signal at monitoring section A1, and G -1 (t) represents the deconvolution part of the empirical Green's function for the cross section, and * represents the convolution calculation.

[0063] Preferably, the method further includes measuring the vertical impact force of the liquid phase on any monitoring section A1;

[0064] The debris flow flume experimental system has a flow depth h arranged on cross section M. m The measuring instrument includes an online pore water pressure sensor mounted on top.

[0065] A flume simulation experiment was conducted to collect the vertical water pressure F of the debris flow at section M under different simulation conditions. fm (t), using experimental data to construct F expressed according to equation (2) fm (t) model,

[0066] F fm (t)=f(ρ m ,h m ,s m (2)

[0067] In the formula, F fm (t), h m These are the vertical water pressure and debris flow depth at section M, respectively. m To simulate the density of debris flow in the experiment, D is the characteristic parameter of the particle size distribution of debris flow, s m The sensing area of ​​the pore water pressure sensor;

[0068] A debris flow flume simulation experiment was conducted, and the debris flow depth at monitoring section A1 was collected. The vertical impact force F of the debris flow liquid phase at section A1 was calculated using the constructed model (2). f1 (t).

[0069] Preferably, D is D 94 The model expression function of equation (2) is equation (2.1).

[0070] Ffm (t)=ρ m gh m s m (D 94 ) 0.04 (2.1)

[0071] In the formula, g is the gravitational acceleration constant.

[0072] Preferably, the empirical Green's function G(t) of the cross-section is constructed using the experimental measurement method of impact force on mud and rock fluid cross-section;

[0073] A debris flow ground motion signal monitoring system was set up at the gully site, including: setting up a monitoring section A2 perpendicular to the gully direction, with section A2 intersecting the gully bed centerline b at point O, and placing surface vibration sensors at point P on one side of the gully bank extension line of section A2.

[0074] When the debris flow passes through, the vertical ground motion signal U2(t) of the debris flow at point P is collected, and the vertical ground motion signal X2 generated at section A2 is extracted according to equation (3).

[0075]

[0076] In the formula, H is the calculation parameter, r is the straight-line distance between point O and point P, L is the length of the debris flow channel, and n is an empirical value, which is 5, 4, and 3 for small, medium, and large debris flows, respectively.

[0077] Substituting X2=U1(t) into the model of Equation 1 constructed in claim 1, the vertical impact force F of the debris flow solid phase at section A2 is calculated. d2 (t).

[0078] Preferably, a rockfall impact test is conducted at point O on the surface of the gully bed. A ground motion sensor is used to collect vertical ground motion signals U at points O and P under the same rockfall impact test conditions. 21 (t), U 22 (t), analyze U 21 (t) and U 22 (t), determine the vertical seismic signal absorption attenuation factor Q of section A2;

[0079] When a debris flow passes through, the vertical ground motion signal U2(t) of the debris flow at point P is collected. The vertical ground motion recovery signal U2′(t) of the debris flow is obtained by compensating and recovering U2(t) using the absorption attenuation factor Q.

[0080] Substitute U2′(t)=U1(t) into equation (3) to calculate and determine X2.

[0081] Preferably, U2(t) is compensated and restored according to equation (4).

[0082]

[0083] In the formula, J and K are calculation parameters, and U 23 (t,f) are intermediate values ​​for calculation, σ is the stability control factor, e is the natural constant, f is the frequency of U2(t), ω0 is the reference angular velocity of U2(t) at 1Hz, ω0=2π, ω is the angular velocity of U2(t), f s Let be the centroid frequency of U2(t).

[0084] Preferably, the debris flow ground motion signal monitoring system further includes a debris flow depth measuring instrument at section A2 to collect the debris flow depth h at section A2, and calculate the vertical impact force F of the debris flow liquid phase at section A2 according to the model of equation (2). f2 (t), where ρ m Take values ​​for debris flow density ρ and h m The values ​​of h and D are determined based on on-site observations.

[0085] Preferably, the vertical impact force F of the debris flow liquid phase at section A2 is calculated according to the models of equations (2.1) and (5). f2 (t), where D 94 Based on on-site observations,

[0086] s m =W×1m (5)

[0087] In the formula, W is the average width of the channel.

[0088] Preferably, the D 94 The power spectral density (PSD2) of signal U2(t) is determined by inversion calculation, and the following scheme is implemented:

[0089] The debris flow ground motion signal monitoring system also includes a debris flow velocity measuring instrument at section A2, which collects the signal U2(t), debris flow velocity u, and flow depth h at section A2, calculates the power spectral density PSD2 of the signal U2(t), and constructs D according to equation (6). 94 Inversion calculation model,

[0090] D 94 =f(PSD2,u,r,c,ξ,v) c ,r,f) (6)

[0091] In the formula, u is the debris flow velocity at section A2, c is the width of section A2, ξ is the source depth correction parameter, with a value of 0.4, and v c Let f be the propagation speed of the Rayleigh wave phase of U2(t) at 1 Hz, and f be the frequency of U2(t).

[0092] Preferably, the model of equation (6) is expressed as equation (6.1).

[0093]

[0094] In the formula, e is the natural constant, and R and B are calculation parameters.

[0095] Example 1

[0096] like Figures 2-3 As shown, the method of the present invention is used to measure the cross-sectional impact force of mud and rock fluid under experimental environmental conditions.

[0097] 1. Construct a mudflow flume experimental system.

[0098] Figure 2 This is a partial schematic diagram of the structure and cross-section M of the debris flow flume experimental system. The debris flow flume experimental system is constructed, with the measurement cross-section M arranged parallel to the axial direction of flume 1. Cross-section M intersects the inner bottom of the flume at line a. Sensors 2, a flow depth measurement device, and a flow velocity measurement device are arranged on line a. Sensor 2 includes a normal stress sensor, a ground vibration sensor, and a pore water pressure sensor. The normal stress sensor measures the impact force on the flume bottom, and the ground vibration sensor measures the ground motion signal.

[0099] In this embodiment, the normal stress sensor is a NOS-F306 uniaxial stress sensor with a frequency of 0.1kHz to 30kHz and a range of 100N. The ground motion sensor is a 1A314E accelerometer with a frequency of 0.5kHz to 20kHz, a range of 50g, and a sampling frequency of 100Hz. After high-pass filtering, high-frequency signals above 1Hz are obtained. The ground motion signal frequency f is 1Hz to 50Hz, and it can directly collect ground motion signal data in the east-west, north-south, and vertical directions. When the acquired signal is at 1Hz, the reference angular velocity ω0 = 2π, the signal angular velocity ω = 2π, and the signal centroid frequency f is... s =1Hz, the Rayleigh wave phase propagation speed v at 1Hz c = 3.75 km / s. A high-speed camera device 3 was selected as the flow depth and velocity measurement device. Image analysis was used to measure the flow depth h of the debris flow in the flume. m The flow velocity is u. The pore water pressure sensor selected is type PX409-100GV, with a range of 15 kPa.

[0100] 2. Measurement of solid phase impact force in mud and rock fluid cross section.

[0101] 2.1 Construct the empirical Green's function G(t).

[0102] Simulated debris flow samples (density ρ) were prepared according to the experimental design. m Based on the particle size distribution characteristic parameter D), simulated debris flow flume experiments were conducted under different simulation conditions. Combined signals [F] of the debris flow at cross-section M were collected in each group of experiments. dm(t),U m (t)]. For any cross-section M under any experimental condition, F dm (t) is the vertical impact force signal of the solid phase of the debris flow, U m (t) is the vertical ground motion signal of the solid phase of the debris flow.

[0103] In this embodiment, the normal stress data collected by the aforementioned sensor is the impact force data F simulating a debris flow sample. T (t), from which the impact force signal F of the debris flow solid needs to be extracted. dm (t). Table 1.1 shows some of the experimental data.

[0104] Table 1.1 Partial Cross-Sectional M Data under Different Solid Impact Experimental Conditions

[0105]

[0106] Using experimental data, an empirical Green's function G(t) for the cross-section is constructed through convolution inversion, which characterizes F on cross-section M. dm (t) and U m (t) Relationship between them.

[0107] Figure 3 This is the empirical Green's function G(t) constructed in this example.

[0108] 2.2 Measurement of vertical impact data of solid phase in mud and rock fluid cross section.

[0109] Arrange any monitoring section A1 within the water tank (11), with section A1 parallel to the measurement section M. Utilize simulated debris flow samples (with ρ values ​​from the debris flow samples in section 2.1) m (Same as D) Conduct a debris flow flume simulation experiment, collect the vertical ground motion signal U1(t) of the debris fluid in the flume (11) at section A1, and calculate the vertical impact force F of the debris flow solid phase at any monitoring section A1 according to the model in Equation 1. d1 (t). Table 1.2 shows the measurement data and calculation results.

[0110] Table 1.2 Partial Vertical Impact Measurement Data of Solid Phase in Slurry Fluid Cross-Section A1

[0111] 1 0.42 0.13 2 0.51 1.54 3 0.75 3.27 4 1.73 5.51 5 1.95 7.16

[0112] 3. Measurement of vertical impact force of liquid phase in mudstone fluid cross section.

[0113] 3.1 Constructing F fm (t) Computational model.

[0114] Simulated debris flow samples (density ρ) were prepared according to the experimental design. mBased on the particle size distribution characteristic parameter D, simulated debris flow flume experiments were conducted under different simulation conditions. Experimental parameters and the water pressure signal F of the debris fluid phase at cross-section M were collected and recorded in each group of experiments. fm (t)(measured by a pore water pressure sensor). Table 1.3 shows some of the experimental data. In this embodiment, D is taken as D. 94 .

[0115] Table 1.3 Partial cross-sectional M data under different experimental conditions of liquid phase impact

[0116] 1 1.11 1250 0.083 0.0012 0.022 2 1.31 1160 0.11 0.0012 0.016

[0117] Construct F expressed in equation 2 using experimental data fm (t) model, as shown in Equation 2.1.

[0118] 3.2 Measurement of vertical impact data of liquid phase in mud and rock fluid cross-section

[0119] Using simulated debris flow samples (and the ρ of some debris flow samples in section 3.1) m (Same as D) Conduct a debris flow flume simulation experiment and collect the debris flow depth h at monitoring section A1. m The vertical impact force F of the debris flow liquid phase at section A1 was calculated using the constructed model 2-1. f1 (t). Table 1.4 shows the measurement data and calculation results.

[0120] Table 1.4 Partial Measurement Data of Vertical Impact of Slurry Fluid in Section A1

[0121] 1 0.022 1250 0.083 0.0012 1.05 2 0.016 1160 0.11 0.0012 1.27

[0122] Example 2

[0123] like Figures 4-9 As shown, the method of the present invention is used to measure the cross-sectional impact force of mud and rock fluid under field gully environment conditions.

[0124] 1. Establish a field monitoring system for the ditch.

[0125] Figure 4 This is a schematic diagram of the structure of the debris flow ground motion signal monitoring system at the gully site.

[0126] A debris flow ground motion monitoring system was constructed at the gully site. The debris flow gully is 3900m long (L) and has an average width (W) of 20m. A monitoring section A2, perpendicular to the gully direction x, was established within the gully. Section A2 has a width (c) of 24m, and its intersection point O with the gully bed centerline (b) is also established. Debris flow depth (h) and velocity (u) measuring devices were installed on section A2. Section A2 was extended to one side of the gully bank, and point P was determined on the extension line. The straight-line distance between point O and point P is r = 15m. A ground motion sensor was installed at point P. The debris flow was a large-scale debris flow, with a debris flow density (ρ) of 1600 kg / m³. 3 The models of all sensors and signal acquisition devices are the same as in Example 1.

[0127] The characteristic parameter D of debris flow particle size distribution was determined by combining field observations and indoor experiments. 94 =0.011m.

[0128] As the debris flow passes through, the vertical seismic signal U2(t) is collected by a vibration sensor at point P. Signal U2(t) is the seismic signal generated by the debris flow at section A2. The flow depth h and flow velocity u at section A2 are also collected at the same time.

[0129] Figure 5 It is the vertical ground motion signal U2(t) of the debris flow.

[0130] 2. Compensation and recovery of U2(t).

[0131] A rockfall impact test was conducted at point O. Vertical ground motion signals under the same rockfall impact test conditions were collected at points O and P using a ground motion sensor (13), denoted as U0. 21 (t), U 22 (t).

[0132] Analysis U 21 (t) and U 22 (t), determine the vertical ground motion signal absorption attenuation factor Q = 2.8 for section A2.

[0133] The vertical ground motion recovery signal U2′(t) of the debris flow is obtained by compensating and recovering U2(t) using the absorption attenuation factor Q. In this embodiment, the model in Equation 4 is specifically used for the recovery compensation of U2(t).

[0134] Figure 6 It is the signal U2′(t) recovered after U2(t) is compensated by the absorption attenuation factor Q.

[0135] 3. Extract signal X2.

[0136] Substitute U2′(t)=U1(t) into Equation 3 to extract signal X2. Signal X2 is the vertical seismic signal generated by cross section A2 of the signal U2(t) generated by the mud and rock fluid.

[0137] Figure 7 It is the vertical seismic signal X2 of the debris flow extracted from section A2.

[0138] 4. Calculation of solid vertical impact force at section A2 of mud and rock fluid.

[0139] Substituting X2=U1(t) into the model of Equation 1 constructed in claim 1, the vertical impact force F of the debris flow solid phase at section A2 is calculated. d2 (t).

[0140] Figure 8 The solid impact force F at section A2 of the mud and rock fluid is... d2 (t).

[0141] 5. Inversion calculation of characteristic parameter D 94 .

[0142] Based on the experimental measurement data, construct D according to Formula 6. 94 The inversion calculation model specifically adopts the model in Equation 6-1.

[0143] Calculate the power spectral density PSD2 of the signal U2(t), based on PSD2, u = 7.0 m / s, c = 24 m, ξ = 0.4, Q = 2.8, v c =3.75km / s, r=15m, f=1Hz~50Hz, calculate the particle size distribution characteristic parameter D of debris flow according to the model in Equation 6-1. 94 =0.01m.

[0144] 6. Calculation of vertical impact force of liquid phase at section A2 of mud and rock fluid.

[0145] The vertical impact force F of the debris flow liquid phase at section A2 is calculated using Equations 2-1 and 5. f2 (t).

[0146] Figure 9 The vertical impact force F of the liquid phase at section A2 of the mud and rock fluid is... f2 (t).

[0147] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0148] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various equivalent changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for experimentally and field measuring the cross-sectional impact force of a debris flow, characterized in that The method includes: Construct a debris flow flume experimental system, and arrange measurement sections M parallel to the flume's axis. Section M intersects the flume's inner bottom at a line. a ,Wire a Sensors are arranged on the surface, including normal stress sensors and ground vibration sensors. A mudflow flume simulation experiment was conducted, and combined signals of mudflow at section M were collected under different simulation conditions. ], and These are the vertical impact force signal and the vertical ground motion signal of the debris flow solid phase on the same cross section M, respectively; the empirical Green's function of the cross section is constructed by convolution inversion using experimental data. Characterizing section M and Interpersonal relationships; An arbitrary monitoring section A1, parallel to the measurement section M, is set up within the debris flow flume to conduct a debris flow flume simulation experiment. Vertical seismic signals of the debris flow within the flume at section A1 are collected. The vertical impact force of the debris flow solid phase at any monitoring section A1 is calculated according to the model in formula (1). （1） In the formula, To monitor the vertical impact force of the debris flow solid phase at section A1, To monitor the vertical ground motion signal at section A1, The deconvolution part of the empirical Green's function for cross-sections. This is for convolution calculation.

2. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 1, characterized in that, The method also includes measuring the vertical impact force of the liquid phase on any monitoring section A1; The debris flow flume experimental system has flow depths arranged on cross section M. Measuring instrument, online a A pore water pressure sensor is installed at the upper level; A flume simulation experiment was conducted to collect the vertical water pressure of the debris flow at section M under different simulation conditions. Using experimental data, construct the expression according to formula (2). Model, （2） In the formula, , These are the vertical water pressure and debris flow depth measured at section M, respectively. To simulate the density of debris flow in the experiment, These are the characteristic parameters of particle size distribution in debris flows. The sensing area of ​​the pore water pressure sensor; A debris flow flume simulation experiment was conducted, and the debris flow depth at section A1 was collected and monitored. The vertical impact force of the debris flow liquid phase at section A1 was calculated using the constructed model (2). .

3. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 2, characterized in that, The D yes The model expression function of equation (2) is equation (2.1). （2.1） In the formula, is the gravitational acceleration constant.

4. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 2, characterized in that, Constructing the empirical Green's function of the cross-section using the experimental measurement method of impact force on mud and rock fluid cross-section ; A debris flow ground motion monitoring system was constructed at the gully site, including: setting up a monitoring section A2 perpendicular to the gully direction, with section A2 aligned with the centerline of the gully bed. b Intersection point O Point on one side of the ditch bank extension line of section A2 P Deploy ground vibration sensors; When the mudslide passed, the collection point P Vertical seismic signal of debris flow The vertical ground motion signal generated at section A2 is extracted according to equation (3). , （3） In the formula, For calculating parameters, For point O With point P The straight-line distance between them. This represents the length of the debris flow channel. For empirical values, 5, 4, and 3 were assigned to small, medium, and large debris flows, respectively. Will Substituting the model of equation (1) constructed according to claim 1, the vertical impact force of the debris flow solid phase at section A2 is calculated. .

5. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 4, characterized in that, At point O An experiment was conducted to test the impact of falling rocks on the surface of the gully bed. Ground vibration sensors were used to collect data at various points under the same experimental conditions. O Location and point P Vertical ground motion signal at the location , ,analyze and Determine the vertical seismic signal absorption attenuation factor of section A2. Q ; When the mudslide passed, the collection point P Vertical seismic signal of debris flow Utilizing absorption attenuation factor Q right Compensation and restoration were performed to obtain the vertical seismic recovery signal of the debris flow. ; Will = Substitute into equation (3) to calculate and determine. .

6. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 5, characterized in that, According to formula (4) Compensation and restoration shall be carried out. （4） In the formula, , For calculating parameters, To calculate intermediate quantities, To stabilize the control factor, It is a natural constant. for frequency, for The reference angular velocity at 1Hz , for angular velocity, for The frequency of the center of mass.

7. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 4, characterized in that, The debris flow ground motion signal monitoring system also includes a debris flow depth measuring instrument at section A2 to collect debris flow depth data at section A2. The vertical impact force of the debris flow liquid phase at section A2 was calculated according to the model in equation (2). ,in, Take the value of debris flow density , Value , D Determined based on on-site observations.

8. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 3, characterized in that, The vertical impact force of the debris flow liquid phase at section A2 was calculated using equations (2.1) and (5). ,in, Based on on-site observations, ＝ （5） In the formula, This represents the average width of the channel.

9. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 8, characterized in that, The Using signals power spectral density The inversion calculation determines the implementation according to the following scheme: The debris flow ground motion signal monitoring system also includes a debris flow velocity measuring instrument at section A2 to collect signals at section A2. Debris flow velocity Flow depth Calculate signal power spectral density Construct according to formula (6) Inversion calculation model, （6） In the formula, The velocity of the debris flow at section A2 is [value missing]. The width of section A2 This is a correction parameter for the focal depth, with a value of 0.

4. for The propagation speed of the Rayleigh wave phase at 1 Hz for The frequency.

10. The method for experimental and field measurement of impact force on mud and rock fluid cross-sections according to claim 9, characterized in that, The model of equation (6) is expressed as equation (6.1). （6.1） In the formula, It is a natural constant. and These are the parameters for calculation.

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