CN116911206A - Debris flow channel single-wide-diameter flow measuring and calculating method, monitoring and early warning method and system - Google Patents
Debris flow channel single-wide-diameter flow measuring and calculating method, monitoring and early warning method and system Download PDFInfo
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Abstract
The invention discloses a debris flow channel single-wide runoff measuring and calculating method, a monitoring and early warning method and a system. Aiming at the situation that a single-wide-diameter flow calculation scheme does not exist in the prior art, the invention provides a debris flow channel single-wide-diameter flow measuring and calculating method. The optimization scheme of the method comprises a method for measuring and calculating characteristic parameters of surface runoff conditions based on runoff process lines and constructing regional surface runoff process lines by utilizing rainfall distribution data. The invention provides a method for monitoring and early warning occurrence of a gully-type debris flow, which is realized by utilizing a single-wide runoff measuring and calculating scheme of a debris flow channel, and is used for measuring and calculating occurrence risk of the debris flow and rainfall threshold of induced debris flow; and providing a debris flow channel formation area monitoring and early warning system. The single wide runoff measuring and calculating method solves the technical problem of measuring the single wide runoff in a mathematical model mode, and expands the effective utilization prospect of the index. The calculation method is completed by using mathematical model calculation, and is easy to butt joint or apply in various debris flow control technical schemes.
Description
Technical Field
The invention relates to a debris flow monitoring and early warning technical scheme, in particular to a debris flow channel formation area single-wide runoff measuring and calculating method, a debris flow rainfall threshold measuring and calculating method, a debris flow monitoring and early warning method and application of the methods. Belongs to the technical field of geological disaster monitoring and measuring and the technical field of geological disaster prevention and control.
Background
The valley type debris flow is usually the type of debris flow mainly corroded by slopes, is the most common type of debris flow in mountainous areas in rainfall season, and has extremely high degree of harm to social economy and ecological environment in mountainous areas. The gully-type debris flow is mainly caused by erosion of the earth surface by precipitation of a certain scale, damage of the stable structure in the soil body and the entrainment of a large amount of earth and stones along with the surface runoff.
The debris flow monitoring and early warning technology is one of main research contents in the mountain land geological disaster prevention and control field. The prior art CN2018107475705 discloses a watershed debris flow early warning scheme, which is a debris flow monitoring early warning technology established on the basis of a debris flow rainfall I-D curve threshold construction method. The method for constructing the I-D curve threshold comprises the steps of firstly obtaining drainage basin underlying surface data required by numerical simulation of Richard models and Van Genuchten equations, starting a hydrologic simulation process under a given rainfall intensity condition, judging stability and flow production conditions of grids of the drainage basin along a time sequence, calculating the volume weight of a water-soil mixture, recording data conforming to control points to fit the I-D curve, and finally obtaining a group of I-D thresholds under a front-stage rainfall condition. According to the method, the hydrologic model is utilized to simulate the precipitation condition change of the debris flow basin as output, then the analysis means based on the water-soil coupling characteristic change trend in the physical process of debris flow formation is utilized to generate the dynamic change of the volume weight value rho of the water-soil mixture as intermediate quantity, and an I-D curve equation is generated by fitting to determine the monitoring threshold value of debris flow occurrence, so that monitoring and early warning of debris flow occurrence are realized. The technology represents the basic conception of the existing gully-type debris flow monitoring and early warning technical scheme, namely, precipitation data is input as a hydrologic model, key hydrologic parameters for inducing debris flow formation are obtained through hydrologic process numerical simulation, and then different types of water and soil characteristic indexes are further calculated and used as monitoring objects of debris flow occurrence early warning.
The existing debris flow monitoring and early warning technology can be applied to debris flow monitoring and early warning with precipitation as a decisive inducing factor, but has defects when being applied to gully-type debris flow. The main disadvantage is that the type of soil and water characteristic index selected (the soil and water mixture volume weight value ρ selected in CN 2018107475705) is not an ideal index for characterizing channel erosion. The prior research finds that the index for representing the surface runoff characteristics is a powerful index for monitoring whether the debris flow formed by the flood erosion ditch bed reaches critical conditions or not, wherein the powerful index comprises the runoff depth, the single-width runoff quantity and the like. However, the prior art has not used the single wide runoff as the monitoring object index of the debris flow monitoring and early warning scheme. Even in the field of geological disaster prevention and treatment research, a single wide runoff index is only used as an incidental description index when the runoff total amount index is used for a long time, and is not effectively utilized. The reason for forming the image is that the prior art does not solve the calculation problem of single wide-diameter flow, so that the single wide-diameter flow cannot be used as a key index in the research field of various debris flows or high-sand-content floods, and the measuring and calculating technology of the index cannot be fused with the upstream hydrologic condition simulation technology and the downstream debris flow monitoring and early warning technology.
Disclosure of Invention
The invention aims to provide a surface form wide runoff measuring and calculating method and a debris flow monitoring and early warning scheme based on the method.
In order to achieve the above purpose, the invention firstly provides a method for measuring and calculating the single-width runoff of the debris flow channel, which is used for measuring and calculating the single-width runoff of the earth surface of the debris flow channel forming area. The technical scheme is as follows:
a debris flow channel single-wide-diameter flow measuring and calculating method is characterized by comprising the following steps of: measuring and calculating single-width runoff of a ground surface calculation unit of the debris flow channel formation area; basic data are acquired through field investigation, a calculation unit is set, for each calculation unit, a large value of a calculation result is calculated according to an equation set of a formula 1 and is taken as a single-wide-diameter flow q calculation result of the calculation unit,
in the formulas 1-1 and 1-2, the q-forming region calculates the unit surface form wide diameter flow, m 3 ，
τ bx 、τ by The component of the friction stress tau between the water flow and the ground in the x-direction and in the y-direction,
Pa，
h-surface runoff depth, m, collected by on-site monitoring or determined from base data,
ρ -water density, constant, t/m 3 ，
g-gravitational acceleration constant, m/s 2 ，
n-roughness coefficient, the value is 0.035-0.04,
components of u, V-radial flow average velocity V in x-direction, y-direction, m 3 S, on-site monitoring acquisitions or from basic data,
c-the talent factor, determined by the base data;
the x direction is the communication direction, and the y direction is the vertical debris flow channel direction.
In the debris flow channel single-wide runoff measuring and calculating method, parameters h, u and v represent surface runoff condition characteristics and are important data bases for calculating single-wide runoff. Generally, the surface runoff depth h and the runoff average flow velocity V can be obtained through field measurement, historical observation records and the prior art for measuring and calculating h and V, and particularly in the technical field of debris flow monitoring, a mature field monitoring technical scheme exists. However, the values of h, u, v determined by the history have no scientific mathematical expression form, and cannot provide a sufficient data scale for constructing a correlation model; the values of h, u and v determined by the existing calculation method are not completely consistent with the single wide-diameter flow measurement in the invention in the measurement principle, and are not beneficial to constructing a complete and comprehensive calculation model. The invention further provides an optimization scheme of the debris flow channel single-wide runoff measuring and calculating method, and mathematical expression forms of parameters h, u and v are established based on runoff process lines. The method specifically comprises the following steps:
acquiring surface runoff process line data of a debris flow channel formation area, and calculating 3 indexes of surface runoff condition characteristics of the formation area by taking the runoff process line data as input through combined type 2-7: h. u, v,
in the above formulas 2 to 7, t-calculates a time variable, s,
a-a flow conservation vector,
f. j-is the component of the flux vector in the x-direction and y-direction respectively,
s b source term vector of the ditch bed surface gradient effect,
s f source term vector of the ditch bed surface friction effect,
beta-ditch bed surface gradient, degree, determined by the basic data.
Typically, the surface runoff process line may be obtained through local historical observations, or scientifically borrowed from data from regions of similar topography and hydrologic conditions. In order to improve the field performance of single wide runoff measurement, the method for acquiring the surface runoff process line is further optimized, and specifically comprises the following steps:
the data acquisition of the formation area surface runoff process line comprises the following steps: rainfall distribution data is obtained, a formation region surface runoff calculation model expressed by H is established (formula 8 and formula 9) to obtain a formation region surface runoff process line,
in the formulas 8 and 9, the depth of the surface flow of the H-forming region, mm,
p-rainfall intensity, mm, rainfall distribution data,
S 2 the maximum potential water storage capacity at the surface of the formation area, mm,
C n -runoff curve number, value 35-80.
In the above-mentioned optimization scheme, the acquisition of the rainfall distribution data can be constructed by using weather forecast data, or by using extreme rainfall event data, or by monitoring rainfall data in real time. The three are respectively the future, history and current rainfall distribution data. The construction of rainfall distribution data using extreme rainfall event data specifically may use rainfall recurrence period data. Building a rainfall distribution number using extreme rainfall event dataFrom this, the rainfall intensity H at different reproduction periods can be calculated according to the formula 10 p Generating a data set [ H ] p ]，
In 10, H p Rainfall intensity at different reproduction periods, mm/h,
K p rainfall duration coefficient, determined from the formation local storm map set
And (3) monitoring the average rainfall of the early warning area, wherein the average rainfall is determined by a local storm map set of the formation area.
Based on the debris flow channel single-wide-diameter flow measuring and calculating method, the invention further provides a gully-type debris flow occurrence monitoring and early warning method, which has the following technical scheme:
a method for monitoring and early warning occurrence of a gully-type debris flow by utilizing the debris flow channel single-width runoff measuring and calculating method is characterized in that: the method comprises the steps of defining a debris flow channel forming area as a monitoring and early warning area, and measuring and calculating the surface form wide diameter flow q of each calculation unit in the monitoring and early warning area; for each calculation unit, if the surface form wide runoff q is more than or equal to the surface form wide runoff critical value q c The marking calculation unit is a destabilization unit, and otherwise, the marking calculation unit is a stabilization unit; when the proportion of the number of the destabilizing units in the number of all the computing units reaches a destabilizing ratio threshold value, judging that the monitoring and early-warning area has a gully-type debris flow occurrence risk; the critical value q of the surface form wide diameter flow of each computing unit c The calculation determination is performed in accordance with 11,
in formula 10, q c -critical value of surface form wide runoff, m 3 ，
θ—average slope, degree of the debris flow channel formation region, determined from the basic data,
d 84 、d 16 the grading number, m, of the debris flow source soil particles is determined by basic data,
C u the non-uniformity coefficient of the source soil of the debris flow is determined by the basic data,
C c -the coefficient of curvature of the source soil of the debris flow is determined from the basis data.
The method for monitoring and early warning the occurrence of the gully-type debris flow is characterized in that on the basis of measuring and calculating the single wide runoff quantity q of each calculation unit, the measuring and calculating value and the single wide runoff quantity critical value q are calculated c And if the calculated value is not smaller than the critical value, marking the calculation unit as an instability unit, and judging that the monitoring early-warning area has a valley-type debris flow occurrence risk when the ratio of the number of the instability units to the number of all calculation units in the monitoring early-warning area reaches an instability ratio threshold value, and sending out a corresponding warning signal. Further, by setting the threshold values of the destabilizing duty ratios of different grades, the grading early warning of the occurrence risk of the debris flow can be primarily realized. The destabilizing duty cycle threshold may be determined with reference to existing methods. The method for monitoring and early warning the occurrence of the gully-type debris flow can directly take the single-width runoff q as a monitoring object index. In the optimization scheme, if the scheme of taking the surface runoff process line data of the debris flow channel formation area as input to measure and calculate the surface runoff condition characteristics of the formation area is adopted, a rainfall event (which can be called a risk rainfall event) which causes the number proportion of the unstable calculation units in the whole formation area to reach the unstable proportion threshold value can be calculated and marked, and the rainfall condition of the risk rainfall event is further counted, so that a rainfall condition threshold value for forming early warning of the occurrence of the debris flow in the formation area can be constructed. In the optimization scheme, rainfall distribution data can be used as a starting point, and the rainfall data can be directly used as a monitoring object index, so that a debris flow monitoring and early warning technical route is shortened.
Furthermore, the monitoring and early warning method can also calculate the rainfall threshold of the induced gully-type debris flow in the monitoring and early warning area. The method specifically comprises the following steps: constructing rainfall distribution data of a research area, calculating the surface runoff condition characteristics of the formation area under different rainfall conditions by taking the rainfall distribution data as input, and constructing a shape according to the corresponding surface form wide runoff quantity qRegional rainfall distribution data and a surface form wide runoff q two-dimensional curve; calculating the critical value q of the surface form wide runoff of each calculation unit according to 11 c Summarizing the data of the whole research area, constructing a change curve of the proportion of the destabilizing calculation units in the research area along the real-time wide-diameter flow, and marking rainfall events, which lead the proportion of the destabilizing calculation units in the research area to reach a destabilizing proportion threshold value, as destabilizing rainfall events; and counting rainfall condition thresholds in the unsteady rainfall event.
The invention also provides a debris flow channel formation area monitoring system, which takes the debris flow channel single-width runoff measuring and calculating method and the trough-type debris flow occurrence monitoring and early warning method as technical cores, and can monitor the single-width runoff of the formation area surface computing unit and monitor the debris flow occurrence risk in the formation area. The technical scheme is as follows:
a debris flow trench formation area monitoring system, characterized by: monitoring the surface form wide runoff of the debris flow channel forming area; defining a debris flow channel forming area as a monitoring and early warning area, determining a measuring section of a computing unit in the monitoring and early warning area, and arranging measuring equipment on the measuring section and connecting with an upper computer/computing center signal; inputting basic data of a monitoring early warning area into an upper computer/computing center, and acquiring runoff characteristic data by measuring equipment and inputting the runoff characteristic data into the upper computer/computing center; the upper computer/computing center calculates the single wide runoff of the earth surface computing unit of the debris flow channel forming area according to the single wide runoff measuring and calculating method of the debris flow channel.
The monitoring system is further provided with a rain gauge in the monitoring and early warning area, rainfall data is input to the upper computer/computing center in real time, and then the upper computer/computing center can monitor the occurrence risk of the debris flow in the formation area by using the trough-type debris flow occurrence monitoring and early warning method.
The field investigation in the technology comprises various geological investigation, stepping investigation, mapping and measurement works aiming at the mountain torrent mud-rock flow channel field of the engineering site, and the prior simulation experiment, test experiment, observation experiment, analysis experiment, history disaster record acquisition, relevant technical specifications, and experience methods and data acquisition with reference and reference functions in the field. The data obtained by the field investigation are collectively referred to as basic data of the present technical scheme.
Compared with the prior art, the invention has the beneficial effects that: (1) Aiming at the defect that the prior art lacks a calculation scheme for measuring and calculating the surface form wide runoff of the debris flow forming area, the invention particularly provides a calculation method for measuring and calculating the surface form wide runoff of the debris flow forming area, and solves the technical problem which cannot be solved by the prior art. The single wide-diameter flow measurement and calculation method is completed by utilizing mathematical model calculation based on advanced investigation data, has high scientificity, and is easy to apply to various debris flow control technical schemes or expand to corresponding debris flow control technical schemes. The single wide runoff measuring and calculating method solves the technical problem that the single wide runoff is measured in the debris flow research field in a mathematical model mode, and therefore the effective utilization prospect of the index in research and technical development is expanded. (2) The method for monitoring and early warning occurrence of the valley type debris flow based on the single wide runoff measuring and calculating method can measure and calculate occurrence risks of the debris flow in an early warning area and rainfall threshold values for inducing the debris flow. (3) The system can monitor single-wide-diameter flow of the early-warning forming area and occurrence risk of the debris flow.
Drawings
Fig. 1 is a schematic technical route diagram of a method for monitoring and early warning occurrence of a gully-type debris flow.
Fig. 2 a-2 b are lines of runoff flow processes under different rainfall durations and different rainfall recurrence periods.
Fig. 3a to 3d are single wide-diameter flow q monitoring curves of the monitoring and early-warning area under different rainfall reproduction period conditions.
FIG. 4 is an I-D rainfall threshold curve.
Detailed Description
Preferred embodiments of the present invention will be further described with reference to the accompanying drawings.
Example 1
As shown in fig. 1 to 4, the invention designs a gully-type debris flow occurrence monitoring and early warning technical scheme for a debris flow channel.
Fig. 1 is a schematic technical route diagram of a method for monitoring and early warning occurrence of a gully-type debris flow.
1. On-site investigation of monitoring and early warning area
The Zhejiang province is 33 provinces and one-step mud-rock flow small river basin (namely mud-rock flow channel), belonging to the valley-type mud-rock flow easy-occurrence topography. The channel forming region is defined as a monitoring and early-warning region, short for early-warning region, of the project monitoring and early-warning system.
Basic data is obtained by field investigation of a monitoring and early-warning area, which comprises
(1) Debris flow trench DEM raster data. Setting the DEM grid as a calculation unit. Each calculation unit has an area of about 8 x 8m 2 The total of 720 calculation units in the monitoring and early warning area are provided.
(2) The material source grain composition and formation area topography condition data of the monitoring and early-warning area are configured in each DEM grid (the grain size distribution of loose deposit in the monitoring and early-warning area is shown in table 1, and the grain cross section characteristics of the monitoring and early-warning area are shown in table 2).
TABLE 1 particle size distribution of the loosely packed areas formed
| D 16 (mm) | D 50 (mm) | D 84 (mm) |
| 3.1 | 28 | 79.2 |
TABLE 2 formation of regional valley section features
| Bottom width (m) | θ(°) | C u | C c | CN |
| 5.5 | 21 | 20 | 0.3 | 60 |
(3) The extreme rainfall event data of the monitoring and early-warning area is obtained and is a storm chart set of 5 years of first meeting, 10 years of first meeting, 20 years of first meeting and 100 years of first meeting of the monitoring and early-warning area.
2. Important parameter calculation
2.1 calculating the critical value q of the surface form wide diameter flow c
In this embodiment, since the consistency of the water and soil conditions of each calculation unit is high, in order to save calculation power, the critical value q of the surface form wide-diameter flow is calculated only for the whole monitoring and early-warning area c And matching the result value to each calculation unit as the critical value q of the surface form wide diameter flow of each calculation unit c 。
Will be theta, d 84 、d 16 、C u 、C c Substituting the parameter value into 11, and calculating to obtain the ground form wide runoff critical value q calculated in the monitoring and early warning area c ＝0.024m 2 /s。
2.2 construction of monitoring Pre-alarm region to construct rainfall distribution data
Based on the storm map sets of different regression periods, calculating according to a formula 10 to obtain extreme rainfall event data of the monitoring and early-warning area to construct rainfall distribution data. Table 3 is the data of the different regression phases of the rainfall distribution.
TABLE 3 rainfall distribution data (total rainfall: mm) at different regression periods
2.3 construction of surface runoff Process line of monitoring and early-warning area
And measuring and calculating the surface runoff process line of the monitoring and early warning area according to the rainfall distribution data in the table 3 and the formula 8 and the formula 9. The surface runoff process line is a time course curve of the surface runoff depth H under the condition of different rainfall reproduction periods. Fig. 2a and 2b are respectively the runoff flow process lines under the conditions of different rainfall durations and different rainfall recurrence periods. Fig. 2a shows the distribution of runoff in different rainfall reproduction periods of rainfall duration 1h and 3h, and fig. 2b shows the distribution of runoff in different rainfall reproduction periods of rainfall duration 6h and 24 h.
2.4 constructing a characteristic distribution curve of the surface runoff condition of the monitoring and early-warning area
And taking runoff process line data as input, and measuring and calculating surface runoff condition characteristic distribution curves of the monitoring and early-warning area by using the combined type 2-7, wherein the characteristic distribution curves are the surface runoff depth h, the runoff average flow velocity V and components u and V of V in the x and y directions respectively. For example, the hydrodynamic conditions for the formation of the zone at a 24 hour recurring period of 100 years 33600 seconds are shown in Table 4.
TABLE 4 formation of index data (local) for regional surface runoff condition characteristics
| Depth of surface runoff h (m) | Classification u (m/s) of V in x-direction | Classification V (m/s) in y-direction of V |
| 0.1407 | 0.2727 | 0.1639 |
| 0.1458 | 0.3071 | 0.2564 |
| 0.1097 | 0.2427 | 0.2557 |
| 0.0957 | 0.2645 | 0.1382 |
| 0.0985 | 0.2185 | 0.2103 |
| 0.0937 | 0.1769 | 0.1831 |
| 0.0751 | 0.0591 | 0.2323 |
2.5 constructing a rainfall condition early warning and monitoring curve of the monitoring and early warning area
Calculating the single wide runoff q of each calculation unit under different rainfall reproduction period conditions by using a surface runoff condition characteristic distribution curve according to a formula 1 (a Xuetalent coefficient C is calculated by using a Manning formula), and determining a change curve of the single wide runoff q of each calculation unit along rainfall time under different rainfall reproduction period conditions;then the critical value q of the surface form wide diameter flow of each calculation unit is overlapped c Can monitor whether the single-wide-diameter flow q of the real-time unit in the whole monitoring and early-warning area reaches the q of the single-wide-diameter flow q under the condition of different rainfall reproduction periods c The method comprises the steps of carrying out a first treatment on the surface of the All the calculation unit data are further summarized, and the instability calculation units (the real-time wide-diameter flow q is more than or equal to q) in the early warning area can be monitored c The calculating unit) of the real-time wide-diameter flow, and a change curve of the calculating unit of the instability in the early warning area along the real-time wide-diameter flow is measured. Fig. 3a to 3d are single wide-diameter flow q monitoring curves of the monitoring and early-warning area under different rainfall reproduction period conditions. Wherein, fig. 3a (rainfall duration is 1 h), fig. 3b (rainfall duration is 3 h), fig. 3c (rainfall duration is 6 h), and fig. 3d (rainfall duration is 24 h) are respectively single wide-diameter flow distribution curves of the debris flow monitoring and early warning area when the runoff is peak (maximum) under different rainfall durations. In each graph of fig. 3, the horizontal axis is the single wide-diameter flow q, the vertical axis is the corresponding percentage of the single wide-diameter flow of the early warning area, and the curve represents the distribution characteristics of the single wide-diameter flow of the early warning drainage basin when the runoff of the monitoring early warning area reaches the peak flow. The specific meaning is that in the whole monitoring and early warning area, the current single-width runoff of all the calculation units are sequenced from small to large according to the numerical value, and then percentage value is taken. The meaning of each point coordinate (x, y) on the curve is that the current single-width diameter flow q with y in all calculation units of the early warning area is smaller than or equal to the value x. For example, when the single wide runoff value threshold is 0.024 (x axis), the percentage is 85% (y axis), which means that the single wide flow value of 1-85% = 15% of the computing units in the current whole area is greater than or equal to 0.024, that is, 15% of the computing units are destabilizing units.
3. Determining rainfall combination condition threshold value of monitoring and early warning area
In this embodiment, the destabilization duty cycle threshold is set to 10% according to the prior art. According to fig. 3a to 3d, selecting a rainfall event which causes the instability of more than 10% of the computing units, marking the rainfall event as a risk rainfall event, and computing a rainfall condition threshold of the risk rainfall event, namely, monitoring and early warning the rainfall condition threshold. In this embodiment, an I-D curve is selected as the rainfall condition threshold. The method specifically comprises the following steps: calculating the rainfall duration (h) and the rainfall intensity (mm/h) of the risk rainfall event, and drawing the risk rainfall event in a coordinate system taking the rainfall duration (h) as an abscissa and the rainfall intensity (mm/h) as an ordinate to obtain an I-D rainfall threshold curve. Fig. 4I-D rainfall threshold curves (gray dots represent risk rainfall events). And determining a rainfall combination condition threshold value which can induce debris flow in the monitoring and early warning area by using the I-D rainfall threshold value curve.
Claims (9)
1. The debris flow channel single-width runoff measuring and calculating method is characterized by comprising the following steps of: measuring and calculating single-width runoff of a ground surface calculation unit of the debris flow channel formation area; basic data are acquired through field investigation, a calculation unit is set, for each calculation unit, a large value of a calculation result is calculated according to an equation set of a formula 1 and is taken as a single-wide-diameter flow q calculation result of the calculation unit,
in the formulas 1-1 and 1-2, the q-forming region calculates the unit surface form wide diameter flow, m 3 ，τ bx 、τ by The component of the friction stress tau between the water flow and the ground in the x-direction, y-direction, pa,
h-surface runoff depth, m, collected by on-site monitoring or determined from base data,
ρ -water density, constant, t/m 3 ，
g-gravitational acceleration constant, m/s 2 ，
n-roughness coefficient, the value is 0.035-0.04,
components of u, V-radial flow average velocity V in x-direction, y-direction, m 3 S, acquired by on-site monitoring or determined from basic data, C-the Xuetalent coefficient, determined from the underlying data,
the x direction is the debris flow channel direction, and the y direction is the vertical debris flow channel direction.
2. The method of claim 1, wherein: obtaining surface runoff process line data of a debris flow channel formation area, calculating and forming area surface runoff condition characteristics by taking the runoff process line data as input, wherein the surface runoff condition characteristics comprise h, u and v,
in the formulas 2 to 7, t-calculates a time variable, s,
a-a flow conservation vector,
f. j-is the component of the flux vector in the x-direction and y-direction respectively,
s b source term vector of the ditch bed surface gradient effect,
s f source term vector of the ditch bed surface friction effect,
beta-ditch bed surface gradient, degree, determined by the basic data.
3. The method of claim 2, wherein: the surface runoff process line data of the formation area is obtained according to the following steps: obtaining rainfall distribution data, establishing a formation region surface runoff calculation model expressed by H to obtain a formation region surface runoff process line,
in the formulas 8 and 9, the depth of the surface flow of the H-forming region, mm,
p-rainfall intensity, mm, rainfall distribution data,
S 2 the maximum potential water storage capacity at the surface of the formation area, mm,
C n -runoff curve number, value 35-80.
4. A method of measuring according to claim 3, wherein: the rainfall distribution data is constructed by utilizing weather forecast data, or by utilizing extreme rainfall event data, or by monitoring rainfall data in real time.
5. The method of measuring and calculating according to claim 4, wherein: the construction of rainfall distribution data by utilizing the extreme rainfall event data is to calculate and determine rainfall intensity H in different reappearance periods according to 10 p The product can be obtained by the method,
in 10, H p Rainfall intensity at different reproduction periods, mm/h,
K p -a coefficient of duration of rainfall,min, determined from the local storm map set of the formation region,
and monitoring the average rainfall of the early warning area, wherein the average rainfall is mm and is determined by a local storm map set of the formation area.
6. The method for monitoring and early warning occurrence of the gully-type debris flow by using the single wide runoff measuring and calculating method of the debris flow channel according to any one of claims 1 to 5 is characterized by comprising the following steps: the method comprises the steps of defining a debris flow channel forming area as a monitoring and early warning area, and measuring and calculating the surface form wide diameter flow q of each calculation unit in the monitoring and early warning area; for each calculation unit, if the surface form wide runoff q is more than or equal to the surface form wide runoff critical value q c The marking calculation unit is a destabilization unit, and otherwise, the marking calculation unit is a stabilization unit; when the proportion of the number of the destabilizing units in the number of all the computing units reaches a destabilizing proportion threshold value, judging that the monitoring and early-warning area has a gully-type debris flow occurrence risk; the critical value q of the surface form wide diameter flow of each computing unit c The calculation determination is performed in accordance with 11,
in formula 11, q c -critical value of surface form wide runoff, m 3 ，
θ—average slope, degree of the debris flow channel formation region, determined from the basic data,
d 84 、d 16 the grading number, m, of the debris flow source soil particles is determined by basic data,
C u the non-uniformity coefficient of the source soil of the debris flow is determined by the basic data,
C c -the coefficient of curvature of the source soil of the debris flow is determined from the basis data.
7. The method of monitoring and warning according to claim 6, characterized in that: also comprises a measuring and calculating monitoring early warning area for inducing the gulletThe implementation method of the rainfall threshold of the debris flow comprises the following steps: constructing rainfall distribution data of a research area, calculating the surface runoff condition characteristics of the area formed under different rainfall conditions by taking the rainfall distribution data as input, and constructing a two-dimensional curve of the rainfall distribution data of the area and the surface runoff q corresponding to the surface runoff q; calculating the critical value q of the surface form wide runoff of each calculation unit according to 11 c Summarizing the data of the whole research area, constructing a change curve of the proportion of the destabilizing calculation units in the research area along the real-time wide-diameter flow, and marking rainfall events, which lead the proportion of the destabilizing calculation units in the research area to reach a destabilizing proportion threshold value, as destabilizing rainfall events; and counting rainfall condition thresholds in the unsteady rainfall event.
8. Mud-rock flow channel forms district monitoring early warning system, its characterized in that: monitoring the surface form wide runoff of the debris flow channel forming area; defining a debris flow channel forming area as a monitoring and early warning area, determining a measuring section of a computing unit in the monitoring and early warning area, and arranging measuring equipment on the measuring section and connecting with an upper computer/computing center signal; inputting basic data of a monitoring early warning area into an upper computer/computing center, and acquiring runoff characteristic data by measuring equipment and inputting the runoff characteristic data into the upper computer/computing center; the upper computer/computing center calculates the single wide runoff of the earth surface computing unit of the debris flow channel forming area according to the single wide runoff measuring and calculating method of the debris flow channel according to claim 1.
9. The monitoring and early warning system of claim 8, wherein: and a rain gauge is further arranged in the monitoring and early warning area to input rainfall data to the upper computer/computing center in real time, and the upper computer/computing center monitors the occurrence risk of the debris flow in the formation area by using the gully-type debris flow occurrence monitoring and early warning method according to claim 6.
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