Debris flow circulation area slope material source dynamic reserve estimation method based on AutoCAD

Abstract

The invention discloses a debris flow circulation area slope material source dynamic reserve estimation method based on AutoCAD, and relates to the technical field of mountain disasters, and the method comprises the following steps: 1, collecting material source body section geometric data, and constructing an AutoCAD digital twinborn model integrating the material source body section geometric data, the channel distribution length and the channel boundary topological relation; according to the method, a zoning coupling mechanism of a channel runoff strong water power direct erosion zone, a slump response zone and a rainfall and slope runoff weak water power progressive erosion zone is provided, the erosion process is decomposed into a multi-physical mechanism synergistic effect, and compared with a previous method, different damage modes of different parts of a slope slump source body are considered, so that the method has the advantages that the method is simple and convenient to operate; and the requirement of finely estimating the dynamic reserve of the slope material source is met.

Description

Technical Field

[0001] This invention relates to the field of mountain disaster technology, specifically to a method for estimating the dynamic reserves of debris flow sources on slopes in debris flow zones based on AutoCAD. Background Technology

[0002] Debris flows are a common natural phenomenon in mountainous areas, causing enormous losses to my country every year. Rainfall, earthquakes, and other factors generate large amounts of landslide source material along gullies. These source materials are often carried agile in the debris flow path, becoming a significant source of debris flow material and exacerbating its destructive power. Estimating the initiation volume of these source materials under the influence of debris flows is an important engineering problem. Estimating the source volume and thus quantifying the destructive power of debris flows is of great significance, providing crucial parameters for debris flow engineering prevention and control, and meeting engineering requirements.

[0003] Currently, some methods exist for estimating the dynamic reserves of such individual debris sources. Qiao Jianping et al. (2012), in their academic paper "Discussion on Statistical Methods for Dynamic Reserves of Debris Flow Sources in the Most Seismically Affected Area of ​​the Wenchuan Earthquake," published in the *Chinese Journal of Geological Hazard Prevention*, refer to this type of source as gully lateral erosion-slide type debris sources and presents an estimation method for this type of source based on a graphical approach. They also calculate the initiation scale of this type of source based on soil erosion models (such as the RUSLE model) and field observation / experimental statistical models (CN105868442A). However, these methods do not consider the failure process of the slope landslide source body under debris flow action, nor do they consider the amount of soil generated during the landslide process, thus failing to meet the need for precise estimation of the initiation scale of a single slope landslide source body. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for estimating the dynamic reserves of debris flow sources on slopes in debris flow zones based on AutoCAD.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for estimating the dynamic reserves of debris flow source areas on slopes based on AutoCAD includes the following steps:

[0007] Step 1: Collect the geometric data of the material source body profile and construct an AutoCAD digital twin model that integrates the geometric data of the material source body profile, the channel distribution length, and the channel boundary;

[0008] Step 2: Based on the dynamic generation of water level lines in debris flow hydrodynamics, the critical instability point C between the water level line and the channel boundary is located using a boundary intersection algorithm, resulting in:

[0009] Strong hydrodynamic scouring zone of gully runoff The hydraulic shear zone is bounded by the water level line, the outline of the landslide source body, and the channel boundary.

[0010] Step 3: Taking the critical instability point C as the origin of the landslide dynamics, a dynamic instability slope CD is derived along the direction of the soil's natural angle of repose, and a three-level erosion response domain is constructed in synergy:

[0011] landslide response zone The chain-like instability domain is formed by the water level line, the channel boundary, and the dynamically unstable inclined side CD.

[0012] Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff Source profile removal and Slope erosion zone under the influence of subsequent rainfall and runoff;

[0013] Step 4: Use AutoCAD's spatial analysis function to extract... , , The vector area parameter;

[0014] Dynamically assigned erosion coefficient K: based on real-time mapping of a ternary parameter matrix of slope, rainfall intensity, and soil cohesion;

[0015] Step 5: Input the area parameters into the partitioned coupling model:

[0016] ;

[0017] in, , , The regions and model items are strictly correlated, reflecting the synergistic physical mechanisms of direct scouring by strong hydrodynamics of gully runoff, chain-like landslides, and gradual erosion by weak hydrodynamics of slope runoff.

[0018] Preferably, the AutoCAD digital twin model in step one is constructed in the following manner:

[0019] The geometric data of the material source body profile is analyzed into a polyline entity, the channel boundary is extracted as a closed spline curve, a spatial dependency matrix of the material source body and the channel boundary is established, the material source profile and the channel boundary are transformed into a surface region, and the intersection is obtained to generate a direct contact boundary.

[0020] Preferably, the boundary intersection algorithm in step two specifically includes:

[0021] The intensity of debris flows can be dynamically simulated and calculated, and can be divided into scenarios of once-in-ten-year, once-in-twenty-year, once-in-fifty-year, and once-in-a-century events according to engineering design. Specific calculations can be performed using variations of the Manning formula.

[0022] ;

[0023] ;

[0024] Where Q is the flow rate, n is the Manning coefficient, B is the channel width, H is the channel water level depth, R is the hydraulic radius, S is the channel gradient, and A is the channel cross-sectional area.

[0025] Draw the water level line through the channel water level depth H, and obtain the critical instability point C between the water level line and the channel boundary.

[0026] Preferably, the method for generating the dynamic instability slope CD in step three is as follows: starting from the critical instability point C, draw a ray along the direction of the natural angle of repose of the soil, and intersect it with the contour line of the source body or the boundary of the previous erosion response domain at point D.

[0027] The natural angle of repose of the soil can be obtained through field experiments or indoor experiments.

[0028] Preferably, the three-level erosion response domains in step three are as follows:

[0029] Strong hydrodynamic scouring zone of gully runoff Areas directly eroded by strong hydrodynamic forces from flash floods / debris flow channels;

[0030] landslide response zone The soil in the area directly eroded by the strong hydrodynamic flow of the gully will collapse naturally due to its own weight after being carried by the material source, and it will fall into the flash flood / debris flow and participate in the debris flow activity.

[0031] Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff The area is affected by rainfall and runoff, and is mainly characterized by erosion.

[0032] Preferably, the weak hydrodynamic progressive erosion zone in step three is characterized by rainfall and slope runoff. Its geometric shape satisfies:

[0033] It does not come into direct contact with the water level.

[0034] Landslide response zone The traction effect of the landslide creates a progressive retreat boundary.

[0035] Preferably, the dynamic erosion coefficient K in step four is 0.2-0.8 based on the real-time mapping of the ternary parameter matrix of slope-rainfall intensity-soil cohesion.

[0036] Preferably, when the slope is 15-25°, the rainfall intensity is <50mm / h, and the soil cohesion is >15kPa, the value of K is in the range of 0.2-0.4.

[0037] Preferably, when the slope is 25-35°, the rainfall intensity is 50-80 mm / h, and the soil cohesion is 10-15 kPa, the value of K is in the range of 0.4-0.6.

[0038] Preferably, when the slope is >35°, the rainfall intensity is >80mm / h, and the soil cohesion is <10kPa, the value of K ranges from 0.6 to 0.8.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] This invention proposes a "direct hydrodynamic scouring zone in channel runoff". +Landslide Response Zone Weak hydrodynamic erosion caused by rainfall and slope runoff The partitioned coupling mechanism decomposes the erosion process into the synergistic effect of multiple physical mechanisms, clearly distinguishing the source initiation areas dominated by three different mechanisms: boundary intersection algorithm, chain landslide, and slope runoff weak hydrodynamic progressive erosion. This results in a more refined estimation of dynamic reserves that better reflects actual failure modes. Furthermore, this method combines soil mechanics theory with dynamic evolution processes, improving the accuracy of instability range prediction to some extent and effectively reducing the dynamic reserves estimation error compared to traditional single-mechanism models. The division of the three-level erosion response domain is not a simple spatial segmentation, but rather a systematic design of "physical mechanism decoupling - spatiotemporal process differentiation - engineering scenario adaptation," which improves the ambiguity, singularity, and lag in the characterization of erosion processes in previous models, enhancing computational accuracy and efficiency. It also overcomes the limitations of traditional methods that only focus on the fluid-particle interaction erosion process, achieving a one-to-one correspondence between spatial partitioning and physical mechanisms, and considering the failure process of slope landslide source bodies, thus meeting the need for precise estimation of slope source dynamic reserves to some extent. Attached Figure Description

[0041] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts. Wherein:

[0042] Figure 1 A graphical calculation model for the source body of slope collapse;

[0043] Figure 2 This is a shape diagram of the landslide material source 1 in the embodiment;

[0044] Figure 3 This is a shape diagram of the landslide material source 2 in the embodiment;

[0045] Figure 4 This is a shape diagram of the landslide material source 3 in the embodiment;

[0046] Figure 5 The diagram shows the model under different working conditions in the embodiment. Detailed Implementation

[0047] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0048] like Figure 1-5 As shown, a method for estimating the dynamic reserves of debris flow source areas on slopes based on AutoCAD includes the following steps:

[0049] Step 1: Collect the geometric data of the material source body profile and construct an AutoCAD digital twin model that integrates the geometric data of the material source body profile, the channel distribution length, and the channel boundary;

[0050] Specifically, the dimensions of the material source, cross-sectional dimensions, and channel dimensions are collected through actual reconnaissance, drilling, and lidar remote sensing. AutoCAD is then opened, and drawing tools such as polylines (PLINE), splines (SPLINE), or lines (LINE) are used to draw the boundaries of irregular areas, ensuring that the drawn graphic is a closed polygon or curve. The geometric data of the material source, the distribution length of the channel, and the boundary topological relationships are integrated into a unified AutoCAD topological model drawing to construct a dynamic digital twin that accurately reflects the spatial dependence between the material source and the channel, thus realizing the correlation between geometric data and dynamic parameters.

[0051] Step 2: Based on the dynamic generation of water level lines in debris flow hydrodynamics, the critical instability point C between the water level line and the channel boundary is located using a boundary intersection algorithm, resulting in:

[0052] Strong hydrodynamic scouring zone of gully runoff The hydraulic shear zone is bounded by the water level line, the outline of the landslide source body, and the channel boundary.

[0053] Specifically, a variation of the Manning formula is used for calculation:

[0054] ;

[0055] ;

[0056] Where Q is the flow rate, n is the Manning coefficient, B is the channel width, H is the channel water level depth, R is the hydraulic radius, S is the channel gradient, and A is the channel cross-sectional area.

[0057] Based on the Manning formula, the highest water level line is dynamically generated through the channel water level depth H. On the AutoCAD topology model drawing constructed in step one, a vertical line with a length equal to the channel water level depth H is drawn using the polyline (PLINE) drawing tool, with the lowest point G of the channel as the vertex. A horizontal line perpendicular to the vertical line is then drawn, using the end point of the vertical line as the reference point. This horizontal line is the highest water level line. The intersection of the highest water level line and the channel boundary is the critical instability point C, thus obtaining the area of ​​direct hydrodynamic scouring of the channel runoff. The hydraulic shear domain is formed by the water level line, the contour of the landslide source body, and the channel boundary. The water level line is dynamically generated based on physical simulation, which is more consistent with the actual rainstorm debris flow process. The boundary intersection algorithm replaces manual experience judgment to achieve automatic, accurate, and rapid identification of critical instability points.

[0058] Step 3: Taking the critical instability point C as the origin of the landslide dynamics, a dynamic instability slope CD is derived along the direction of the soil's natural angle of repose, and a three-level erosion response domain is constructed in synergy:

[0059] landslide response zone The chain-like instability domain is formed by the water level line, the channel boundary, and the dynamically unstable inclined side CD.

[0060] Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff Source profile removal and Slope erosion zone under the influence of subsequent rainfall and runoff;

[0061] Specifically, on the AutoCAD topology model drawing further constructed in step two, a ray is drawn using the polyline (PLINE) drawing tool with the critical instability point C as the origin, based on the natural angle of repose. This ray intersects the source contour at point D, thus obtaining the dynamic instability slope CD. This results in three closed regions on the AutoCAD topology model drawing, thereby constructing the collapse response zone. Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff and the area directly scoured by the strong hydrodynamic force of the gully runoff. A three-tiered erosion response domain is constructed collaboratively, and the direction of the dynamic hypotenuse is determined by the natural angle of repose, while its length and position dynamically influence... The scope allows the model to have physical plausibility.

[0062] Furthermore, by proposing the concept of "direct hydrodynamic scouring zone of channel runoff" +Landslide Response Zone Weak hydrodynamic erosion caused by rainfall and slope runoff The partitioned coupling mechanism decomposes the soil transport process into the synergistic effect of multiple physical mechanisms:

[0063] Strong hydrodynamic scouring zone of gully runoff : The area directly affected by the water flow;

[0064] landslide response zone Taking the critical point C as the origin, a dynamic instability slope CD is derived along the natural angle of repose, forming a "chain-like instability domain" enclosed by the water level, channel boundary, and CD. This simulates a chain of collapses triggered by initial instability, through the landslide response zone. Introducing the angle of repose to reflect the chain reaction of gravity instability conforms to the principle of soil failure, making the mechanical mechanism explicit. The zoning definition closely integrates the soil mechanical properties (natural angle of repose) and the instability dynamics process, quantifying and spatializing the dynamic process of chain collapse;

[0065] Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff The remaining portion of the source material outline represents the area that may be gradually eroded in the future. The area is designed in a gradually receding form to reflect the dynamic erosion process;

[0066] This method clearly distinguishes the source initiation areas dominated by three different mechanisms: direct scouring by strong hydrodynamics of gully runoff, chain landslides, and gradual erosion by weak hydrodynamics of rainfall and slope runoff. It provides a more refined estimation of dynamic reserves that better reflects actual failure modes. Furthermore, this method combines soil mechanics theory with dynamic evolution processes and proposes a quantitative division method for chain-like instability domains, which improves the accuracy of instability range prediction to a certain extent.

[0067] Step 4: Use AutoCAD's spatial analysis function to automatically extract... , , The vector area parameter;

[0068] Dynamically assigned erosion coefficient K: based on real-time mapping of a ternary parameter matrix of slope, rainfall intensity, and soil cohesion;

[0069] Specifically, based on the AutoCAD topology model drawing obtained in step three, type AREA in the command line and press Enter. Follow the prompts to select each vertex of the irregular area. You can specify points by clicking with the mouse or entering coordinates, or you can directly select the object. After selecting all vertices, press Enter or right-click to end the command. The AutoCAD software will automatically calculate and display the area of ​​the selected region. , , The vector area of ​​the region (unit: ㎡) seamlessly integrates the powerful geometry engine of professional AutoCAD software into the analysis process, realizing efficient, accurate and automated conversion of key geometric parameters (area), avoiding tedious and inefficient manual measurement or data export and import, and effectively improving calculation speed and accuracy.

[0070] Furthermore, based on the real-time assignment of the erosion coefficient K using the ternary parameter matrix of slope-rainfall intensity-soil cohesion, dynamic correction under the coupled effects of multiple environmental factors is achieved, replacing the traditional empirical constant values. Through automatic location of critical instability points, solution of three-level erosion domains, and dynamic assignment of erosion coefficients, the deviation of fixed coefficients is effectively avoided, further improving the calculation accuracy.

[0071] Step 5: Input the area parameters into the partitioned coupling model:

[0072] ;

[0073] in, , , The regions and model items are strictly correlated, reflecting the synergistic physical mechanisms of direct scouring by strong hydrodynamics of gully runoff, chain landslides, and gradual erosion by weak hydrodynamics of rainfall and slope runoff;

[0074] Specifically, , , Regions and model items correspond strictly:

[0075] Strong hydrodynamic scouring of gully runoff → instantaneous activation;

[0076] Gravity collapse → short-term chain reaction failure;

[0077] Weak hydrodynamic erosion caused by rainfall and slope runoff → gradual erosion caused by short-term rainfall and runoff;

[0078] The model structure itself reflects the different damage modes of the source material caused by different instability / erosion mechanisms (direct hydrodynamic scouring from channel runoff, chain slumping, and gradual erosion from rainfall and slope runoff). / The correlation between different zones reflects a positive feedback loop where scour induces landslides, and landslides drive erosion. The contribution of each zone quantifies different erosion patterns. , , The vector area parameter is input into the partitioned coupling model, which strictly corresponds to different erosion mechanisms. The model design realizes a one-to-one correspondence between spatial partitions and physical mechanisms, which not only considers the destruction process of the source body of slope collapse, but also improves the accuracy to a certain extent.

[0079] Furthermore, such as Figure 1 As shown, if the landslide source body is simplified to a triangular shape, the channel shape is uncertain, and its area is taken as... Then, the formula for calculating the starting volume of the landslide source body in the flash flood / debris flow zone is:

[0080] ;

[0081] in, The area directly eroded by the strong hydrodynamic flow of flash floods / debris flow gullies is:

[0082] ;

[0083] The soil in the area directly scoured by the strong hydrodynamic flow of the gully collapses naturally due to its own weight after being carried away by the source material. Its area is:

[0084] ;

[0085] For the area affected by rainfall and runoff, This refers to the area of ​​the slope source body that triggers rainfall and slope runoff erosion, of which... The base and height of a triangle can be obtained directly by measurement, and the area can be calculated according to the triangle area formula.

[0086] L is the length of the landslide source body along the debris flow channel. The angle of repose of the soil. and The angle between the highest water level and the boundary of the debris flow channel. The distance between point F, the intersection of the source contour line and the channel boundary, and point A, the intersection of the highest water level line and the debris flow channel boundary, is given. The distance between point A, the intersection of the highest water level line and the boundary of the debris flow channel, and point B, the intersection of the source contour line and the highest water level line. The distance between point B, the intersection of the source contour line and the highest water level line, and the critical instability point C. The length of the dynamically unstable hypotenuse CD;

[0087] Based on the above calculation formula, it can be seen that this formula requires numerous parameters and is a simplified geometric calculation model, which does not conform to the complex shape of the actual slope landslide source body. Compared with previous calculation models, this is a relatively accurate manual calculation model that considers the failure process of the slope landslide source body. However, in practical engineering applications, using this simplified model is time-consuming and labor-intensive. Considering the powerful functions of industrial software AutoCAD, which can calculate the area of ​​arbitrary geometric shapes, a newly developed accurate estimation model combined with the functions of AutoCAD software can quickly estimate the starting volume of the slope landslide source body in the debris flow area, and the model can be simplified as follows:

[0088] ;

[0089] Furthermore, the simplified model is not simply a patchwork of known methods, but rather establishes a completely new correspondence between the physical mechanism of debris flow erosion and the mathematical model. It organically combines zone area, dynamic coefficient, and source thickness to form a logically rigorous and physically clear dynamic reserve calculation framework. It also works with the AutoCAD spatial engine to extract vector area, which can be directly integrated into the AutoCAD engineering design platform without the need for additional professional software. This lowers the threshold for geological hazard assessment and effectively reduces calculation time. While improving calculation accuracy and precision, it also effectively improves calculation efficiency, thus addressing the industry pain point of "high subjectivity and low accuracy in dynamic reserve estimation" to a certain extent.

[0090] Finally, calculate the total dynamic reserves of all material sources in the circulation area and output the estimated total dynamic reserves.

[0091] The AutoCAD digital twin model in step one is constructed in the following way:

[0092] The geometric data of the material source body profile is analyzed into a polyline entity, the channel boundary is extracted as a closed spline curve, a spatial dependency matrix of the material source body and the channel boundary is established, the material source profile and the channel boundary are transformed into a surface region, and the intersection is obtained to generate a direct contact boundary.

[0093] Specifically, the source body profile is analyzed as a multi-segment line entity (a vector object composed of continuous line segments and inflection points), which can accurately preserve the micro-geometric features such as slope undulation, lithological stratification interfaces, and local steep slopes. Compared with the "homogeneous rectangular / triangle simplified model" used in traditional methods, the multi-segment line entity can control the source body contour error within ±0.5m (based on the millimeter-level drawing accuracy of AutoCAD), and is especially suitable for the morphological restoration of heterogeneous source bodies such as fractured rock masses and layered soil masses.

[0094] Furthermore, the channel boundary is extracted as a closed spline curve (a smooth curve fitted by control points), which can realistically reproduce the meandering shape of natural channels (such as meandering sections and bottleneck sections), avoiding the "angularity error" caused by the polyline approximation.

[0095] Furthermore, the direct contact boundary (the overlapping line between the source body surface region and the channel boundary surface region) generated by the surface region intersection operation accurately locates the "starting line of direct contact between the source body and the channel". This boundary is not only the "initial erosion reference surface" of hydrodynamic action (the water flow first acts on this line and extends into the source body), but also the potential distribution area of ​​the subsequent critical instability point C. Compared with the subjectivity of "artificially delineating the reference line" in traditional methods, the objectivity of this boundary can effectively reduce the error in determining the initial erosion range.

[0096] The boundary intersection algorithm in step two specifically includes:

[0097] The intensity of debris flows can be dynamically simulated and calculated, and can be divided into scenarios of once-in-ten-year, once-in-twenty-year, once-in-fifty-year, and once-in-a-century events according to engineering design. Specific calculations can be performed using variations of the Manning formula.

[0098] ;

[0099] ;

[0100] Where Q is the flow rate, n is the Manning coefficient, B is the channel width, H is the channel water level depth, R is the hydraulic radius, S is the channel gradient, and A is the channel cross-sectional area.

[0101] Draw the water level line through the channel water level depth H, and obtain the critical instability point C between the water level line and the channel boundary.

[0102] Specifically, based on the engineering design, the scenarios are divided into once-in-ten-year, once-in-twenty-year, once-in-fifty-year, and once-in-a-century events. The actual erosion thickness varies under different conditions, and the dynamic reserve scale under different conditions can be calculated based on the actual situation.

[0103] To calculate the erosion thickness Z under different working conditions, we can use the formula for calculating the thickness of the initiating layer shift in rock flow established by Japanese scholar Takahasi in 1978:

[0104] ;

[0105] in, For solid density, The density of pure water; For flow depth; The inclination angle of the ditch; The macroscopic friction coefficient between particles; Shear resistance to water flow; This represents the average concentration of coarse particles along the vertical line.

[0106] like Figure 5 As shown, the erosion thicknesses Z1, Z2, and Z3 under different working conditions were calculated, and the erosion boundaries were drawn on the AutoCAD drawing based on the erosion thicknesses. The erosion boundaries were extended to intersect the waterline at C1, C2, and C3, respectively. Rays were drawn according to the natural angle of repose, intersecting the source contour at D1, D2, and D3, respectively, thus obtaining the dynamic instability hypotenuses C1D1, C2D2, and C3D3 under different working conditions. G1, G2, and G3 are the intersection points of the erosion boundaries and channel boundaries under different working conditions. The areas were extracted from the AutoCAD topology model drawing, and the dynamic storage volume of the source under different working conditions was calculated.

[0107] ;

[0108] ;

[0109] ;

[0110] ;

[0111] This allows for the estimation of actual material reserves based on different operating conditions, making the estimation results more consistent with reality and improving the general applicability of the calculation model.

[0112] The method for generating the dynamic instability slope CD in step three is as follows: starting from the critical instability point C, draw a ray along the direction of the natural angle of repose of the soil, and intersect it with the contour line of the source body or the boundary of the previous level erosion response domain at point D.

[0113] The natural angle of repose of the soil can be obtained through field experiments or indoor experiments.

[0114] The three-level erosion response domains in step three are as follows:

[0115] Strong hydrodynamic scouring zone of gully runoff Areas directly eroded by strong hydrodynamic forces from flash floods / debris flow channels;

[0116] landslide response zone The soil in the area directly eroded by the strong hydrodynamic flow of the gully will collapse naturally due to its own weight after being carried by the material source, and it will fall into the flash flood / debris flow and participate in the debris flow activity.

[0117] Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff The area is affected by rainfall and runoff, and is mainly characterized by erosion.

[0118] Specifically, areas directly scoured by strong hydrodynamic forces from gully runoff. Focusing on the direct effects of strong hydrodynamics in channels (such as turbulent scouring and cavitation effects), this model accurately delineates the "initial region where water flow energy directly acts on the source body" through hydrodynamic simulation and boundary intersection algorithm. Compared with the "uniform erosion assumption across the entire domain" in previous models, the delineation of this region further reduces the calculation error of scouring volume.

[0119] landslide response zone This study reveals the dynamic process of "water erosion → soil instability → chain collapse" and couples the soil's self-weight with the hydrodynamic erosion effect through the instability slope CD derived from the natural angle of repose.

[0120] Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff This study isolates the gradual, weakly hydrodynamic erosion process of slope runoff, consisting of "rainfall infiltration – runoff erosion – particle transport," to avoid confusion with sudden scour and landslide processes. By independently assigning a low erosion coefficient K, the "gradual erosion contribution" of short-term rainfall events to the source body can be quantified.

[0121] Level 3 regions do not exist in isolation, but are connected by spatial adjacency ( → → It forms an organic whole with the destructive processes (hydrodynamic scouring, structural instability, runoff erosion). For example, After the soil in the area was washed away, The area collapsed due to its own weight caused by the exposure of the free surface, and the collapsed body then became a new roughness boundary. The runoff flow pattern in the area, this "scouring-slide-erosion" process, makes the dynamic reserve estimation error more in line with engineering needs than the traditional single mechanism model.

[0122] Furthermore, the division of the three-level erosion response domain is not a simple spatial division, but a systematic design of "physical mechanism decoupling - spatiotemporal process differentiation". This improves the ambiguity, uniformity and lag of previous models in the characterization of erosion processes, improves the calculation accuracy and efficiency to a certain extent, and provides a certain scientific basis for debris flow prevention and control.

[0123] Step 3: Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff Its geometric shape satisfies:

[0124] It does not come into direct contact with the water level.

[0125] Landslide response zone The traction effect of the landslide creates a progressive retreat boundary.

[0126] Specifically, The district, through spatial delineation that "does not directly contact the waterline," clearly separates the erosion process dominated by rainfall and low-intensity slope runoff, and... Area (direct scouring by strong hydrodynamic forces from gully runoff) The formation mechanisms of the area (hydrodynamic erosion + self-weight collapse) are complementary, through Independent modeling of the area allows for precise quantification, avoiding the overestimation error caused by previous models that categorized it under "total water erosion".

[0127] Furthermore, The free surface formed by the landslide will change The stress state of the soil in the zone (such as principal stress direction deflection and shear stress concentration) can be simulated using a "progressive retreat boundary" to reveal the chain reaction of "local collapse → unloading of the soil behind → crack propagation → surface spalling," and the progressive erosion zone caused by weak hydrodynamics from rainfall and slope runoff. The construction method, through a triple control mechanism of "spatial isolation, stress traction, and dynamic evolution," makes up for the shortcomings of previous models in characterizing "indirect strong hydrodynamic erosion processes."

[0128] The dynamic erosion coefficient K in step four is based on a real-time mapping of the ternary parameter matrix of slope, rainfall intensity, and soil cohesion, and its value ranges from 0.2 to 0.8.

[0129] When the slope is 15-25°, the rainfall intensity is <50mm / h, and the soil cohesion is >15kPa, the value of K ranges from 0.2 to 0.4.

[0130] When the slope is 25-35°, the rainfall intensity is 50-80 mm / h, and the soil cohesion is 10-15 kPa, the value of K ranges from 0.4 to 0.6.

[0131] When the slope is greater than 35°, the rainfall intensity is greater than 80 mm / h, and the soil cohesion is less than 10 kPa, the value of K ranges from 0.6 to 0.8.

[0132] Specifically, when the slope is greater than 35°, the K value increases to 0.6-0.8, directly reflecting the mechanism of "steep slopes accelerating the conversion of water flow energy into erosion kinetic energy". When the rainfall intensity is greater than 80 mm / h, the splashing kinetic energy of raindrops reaches 15-20 J / m²・min. Combined with the turbulent effect of surface runoff, the K value enters the high range of 0.6-0.8. For loose deposits with cohesion <10 kPa, the cementation force between particles is weak, and the K value is naturally higher by 0.6-0.8. The ternary parameter matrix forms a continuous K value distribution surface through interpolation, avoiding the abrupt error caused by the traditional "one-size-fits-all threshold". Traditional erosion models mostly use empirical coefficient superposition, while this scheme establishes a physical causal chain of "dynamic input (slope, rainfall intensity) - medium properties (cohesion) - erosion output (K value)" through the ternary parameter matrix. The technical solution of dynamically assigning the erosion coefficient K based on the ternary parameter matrix of slope-rainfall intensity-soil cohesion is beneficial to a certain extent for the refined estimation of erosion intensity quantification.

[0133] Example

[0134] A debris flow gully is located in the epicenter of the Wenchuan earthquake. Three typical slope landslide source bodies have developed in its debris flow area. A debris flow retaining dam is planned to be built downstream. The dynamic storage capacity of the debris flow gully slope source needs to be estimated. Its basic shape is as follows: Figure 2-4 .

[0135] Step 1: Obtain the cross-sectional dimensions of the three landslide material sources and the length of the landslide material sources distributed along the gully, and generate AutoCAD dimensional drawings.

[0136] Step Two: Based on the Manning formula and channel parameters, the water levels at three typical slope landslide source bodies under a 100-year debris flow scenario are calculated to be 6.2m, 6.8m, and 8m, respectively. The AutoCAD drawings of the slope landslide source body profiles are imported into AutoCAD software. The highest water level is drawn in AutoCAD software, and the intersection point with the channel boundary line on the side of the landslide source body is found. The areas directly scoured by strong hydrodynamic forces in the channel runoff, enclosed by the water level line, the outline of the landslide source body, and the channel boundary line, are then obtained. .

[0137] Step 3: Based on the field measurement of the natural angle of repose of the soil as 32°, draw the corner lines of the landslide source body on each slope. This yields the landslide area bounded by the debris flow water level, the outline of the landslide source body, and the corner lines of the natural angle of repose. The remaining area is a zone of gradual erosion due to weak hydrodynamics caused by rainfall and slope runoff. .

[0138] Step 4: Using the area calculation function of the CAD software, obtain the following: , , The area.

[0139]

[0140] Step 5: Input the obtained data into the calculation model The initiation volume of a single slope landslide source body can be obtained. Taking K as 0.4, the calculation yields:

[0141] ;

[0142] ;

[0143] ;

[0144] By summing up the starting volumes of all the landslide source bodies, the dynamic storage capacity of the landslide source bodies on the slope of the flow zone can be obtained:

[0145] .

[0146] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A method for estimating the dynamic reserves of debris flow path surface in debris flow zones based on AutoCAD, characterized in that, Includes the following steps: Step 1: Collect the geometric data of the material source body profile and construct an AutoCAD digital twin model that integrates the geometric data of the material source body profile, the channel distribution length, and the channel boundary; Step 2: Based on the dynamic generation of water level lines in debris flow hydrodynamics, the critical instability point C between the water level line and the channel boundary is located using a boundary intersection algorithm, resulting in: Strong hydrodynamic scouring zone of gully runoff The hydraulic shear zone is bounded by the water level line, the outline of the landslide source body, and the channel boundary. Step 3: Taking the critical instability point C as the origin of the landslide dynamics, a dynamic instability slope CD is derived along the direction of the soil's natural angle of repose, and a three-level erosion response domain is constructed in synergy: landslide response zone The chain-like instability domain is formed by the water level line, the channel boundary, and the dynamically unstable inclined side CD. Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff Source profile removal and Slope erosion zone under the influence of subsequent rainfall and runoff; Step 4: Use AutoCAD's spatial analysis function to extract... , , The vector area parameter; Dynamically assigned erosion coefficient K: based on real-time mapping of a ternary parameter matrix of slope, rainfall intensity, and soil cohesion; Step 5: Input the area parameters into the partitioned coupling model: ； in, , , The regions and model items are strictly correlated, reflecting the synergistic physical mechanisms of direct scouring by strong hydrodynamics of gully runoff, chain-like landslides, and gradual erosion by weak hydrodynamics of slope runoff.

2. The method for estimating the dynamic storage capacity of slope debris flow zone based on AutoCAD according to claim 1, characterized in that: The AutoCAD digital twin model in step one is constructed in the following way: The geometric data of the material source body profile is analyzed into a polyline entity, the channel boundary is extracted as a closed spline curve, a spatial dependency matrix of the material source body and the channel boundary is established, the material source profile and the channel boundary are transformed into a surface region, and the intersection is obtained to generate a direct contact boundary.

3. The method for estimating the dynamic storage capacity of slope debris flow zones based on AutoCAD according to claim 1, characterized in that: The boundary intersection algorithm in step two specifically includes: The intensity of debris flows can be dynamically simulated and calculated, and can be divided into scenarios of once-in-ten-year, once-in-twenty-year, once-in-fifty-year, and once-in-a-century events according to engineering design. Specific calculations can be performed using variations of the Manning formula. ； ； Where Q is the flow rate, n is the Manning coefficient, B is the channel width, H is the channel water level depth, R is the hydraulic radius, S is the channel gradient, and A is the channel cross-sectional area. Draw the water level line through the channel water level depth H, and obtain the critical instability point C between the water level line and the channel boundary.

4. The method for estimating the dynamic storage capacity of slope sediment source in debris flow zones based on AutoCAD, as described in claim 1, is characterized in that: The method for generating the dynamic instability slope CD in step three is as follows: starting from the critical instability point C, draw a ray along the direction of the natural angle of repose of the soil, and intersect it with the contour line of the source body or the boundary of the previous level erosion response domain at point D. The natural angle of repose of the soil can be obtained through field experiments or indoor experiments.

5. The method for estimating the dynamic storage capacity of slope sediment source in debris flow zones based on AutoCAD, as described in claim 4, is characterized in that: The three-level erosion response domains in step three are as follows: Strong hydrodynamic scouring zone of gully runoff Areas directly eroded by strong hydrodynamic forces from flash floods / debris flow channels; landslide response zone The soil in the area directly eroded by the strong hydrodynamic flow of the gully will collapse naturally due to its own weight after being carried by the material source, and it will fall into the flash flood / debris flow and participate in the debris flow activity. Weak hydrodynamic progressive erosion zone caused by rainfall and slope runoff The area is affected by rainfall and runoff, and is mainly characterized by erosion.

6. The method for estimating the dynamic storage capacity of slope sediment source in debris flow flow areas based on AutoCAD, as described in claim 5, is characterized in that: The weak hydrodynamic progressive erosion zone in step three refers to rainfall and slope runoff. Its geometric shape satisfies: It does not come into direct contact with the water level. Landslide response zone The traction effect of the landslide creates a progressive retreat boundary.

7. The method for estimating the dynamic reserves of debris flow path slopes based on AutoCAD according to claim 1, characterized in that: The dynamically assigned erosion coefficient K in step four has a value range of 0.2-0.8 based on the real-time mapping of the ternary parameter matrix of slope-rainfall intensity-soil cohesion.

8. The method for estimating the dynamic reserves of debris flow path slopes based on AutoCAD according to claim 7, characterized in that: When the slope is 15-25°, the rainfall intensity is <50mm / h, and the soil cohesion is >15kPa, the value of K ranges from 0.2 to 0.

4.

9. The method for estimating the dynamic reserves of debris flow path slopes based on AutoCAD according to claim 7, characterized in that: When the slope is 25-35°, the rainfall intensity is 50-80 mm / h, and the soil cohesion is 10-15 kPa, the value of K ranges from 0.4 to 0.

6.

10. The method for estimating the dynamic storage capacity of slope debris flow zone based on AutoCAD according to claim 7, characterized in that: When the slope is >35°, the rainfall intensity is >80mm / h, and the soil cohesion is <10kPa, the value of K ranges from 0.6 to 0.8.

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