Method for judging possibility of forming debris flow by moraine lake outburst and application thereof

Abstract

The invention discloses a method for judging the possibility of forming debris flow by moraine lake outburst, which comprises the following steps of: S1, calculating the average longitudinal gradient J of a downstream channel of a moraine lake, the flood peak flow Q of moraine lake outburst and the particle size characteristic value D of an object source of a downstream drainage basin of moraine lake outburst, and measuring the average width W of the downstream channel of the moraine lake; s2, calculating a moraine lake outburst debris flow possibility evaluation factor P according to the moraine lake downstream channel average longitudinal gradient J, the moraine lake outburst peak flow Q, the moraine lake outburst downstream watershed source particle size characteristic value D and the moraine lake downstream channel average width W; and S3, judging the debris flow occurrence possibility according to the evaluation factor P. The invention further discloses application of the method for judging the possibility of forming the debris flow through moraine lake outburst. According to the method for judging the possibility of forming the debris flow through moraine lake outburst and the application of the method, the problem that the possibility of forming the debris flow through moraine lake outburst cannot be judged in the prior art is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of debris flow prevention and control engineering and water conservancy engineering, and specifically relates to a method for judging the possibility of debris flow formed by the outburst of a moraine lake, and also relates to the application of the method for judging the possibility of debris flow formed by the outburst of a moraine lake. Background Art

[0002] Moraine lakes in high-altitude mountainous areas often experience glacial lake outbursts, forming large-volume outburst floods. When there are sufficient material sources and channel slopes downstream, debris flows often occur. Because the debris flows formed by such glacial lake outbursts have the characteristics of large flow and huge total volume, they may also block the main river channel downstream and burst again to form larger mountain torrents, causing great harm to riverside facilities, roads, residents, etc. along the downstream river channel, forming a disaster chain effect, and causing serious damage to the downstream mountainous areas. However, the outburst of moraine lakes does not necessarily form debris flows, and research is still needed to determine whether debris flows will occur.

[0003] At present, the research on the possibility of debris flow at home and abroad is mainly aimed at the possibility of gully debris flow and slope debris flow. The inducing factors are rainfall. Therefore, the catchment area of ​​gully debris flow and the slope gradient of slope debris flow have important influences on the formation of these two types of debris flow. But the biggest influence is rainfall, because rainfall is both an inducing factor and a water source condition for the formation of debris flow. Other influencing factors include: 1) Valley debris flow: source conditions of debris flow: source particle size, source lithology, weathering degree, structure, fault zone, etc.; terrain conditions of debris flow: channel longitudinal gradient, basin area, basin shape coefficient, gully length, height difference, basin development degree, etc. 2) Slope debris flow: source conditions: parent rock lithology, soil permeability coefficient, clay mineral characteristics and content, etc.; terrain conditions: slope, soil thickness, width, etc. However, the probability of occurrence of these debris flows is far different from the probability of occurrence of debris flows caused by moraine lake outburst: first, the inducing factors, that is, the water source conditions are completely different. The debris flows caused by moraine lake outburst are concentrated with huge moraine lake outburst peak flows; second, the channels downstream of moraine lakes are very wide "U"-shaped valleys due to glacial erosion and a large basin area, and the longitudinal gradient of the channels is relatively small; finally, the material source conditions are often relatively rich and scattered in the wide channels downstream of moraine lakes. Therefore, the original probability of occurrence of valley debris flows is completely inappropriate for the probability of occurrence of such debris flows caused by moraine lake outbursts.

[0004] At present, there is no corresponding research and technical plan to judge the possibility of debris flow caused by moraine lake bursting. However, there is a major strategic demand for highway, railway, hydropower and mountain development and construction in the western high-altitude mountainous areas, which makes the possibility of debris flow caused by moraine lake bursting increasingly important, and this problem needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a method for judging the possibility of a mud-rock flow formed by the outburst of a moraine lake, thereby solving the problem that the prior art cannot judge the possibility of a mud-rock flow formed by the outburst of a moraine lake.

[0006] Another object of the present invention is to provide an application of a method for determining the possibility of a moraine lake burst forming a debris flow.

[0007] The technical solution adopted by the present invention is a method for determining the possibility of a debris flow caused by a moraine lake outburst, comprising the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; S3. Determine the possibility of debris flow based on the possibility evaluation factor P of moraine lake outburst debris flow.

[0008] The present invention is also characterized in that: The calculation process of the average longitudinal gradient drop J in the downstream channel of the moraine lake in S1 is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake.

[0009] The calculation process of the peak discharge Q of the moraine lake outburst in S1 is as follows: Calculate according to formula (2); (2); Where A is the area of ​​moraine lake, unit: m 2 ; Q is the peak flow of moraine lake outburst flood, unit: m 3 / s.

[0010] The calculation process of the characteristic value D of the source particle size in the downstream watershed of the moraine lake outburst in S1 is as follows: Calculate according to formula (3); (3); Among them, F0 is the solidity coefficient of rock properties, which is queried according to the solidity coefficient table; D is the characteristic value of the source particle size in the downstream basin of the moraine lake outburst, unit: m.

[0011] The specific process of S2 is as follows: according to the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate of the moraine lake outburst flood Q, the characteristic value of the source particle size D of the downstream basin of the moraine lake outburst, and the average width W of the channel downstream of the moraine lake, the possibility evaluation factor P of the glacial lake outburst debris flow is calculated according to formula (4); (4); Where g is the acceleration due to gravity, unit: m / s 2 ; W is the average width of the channel downstream of the moraine lake, unit: m.

[0012] The specific process of S3 is as follows: according to the evaluation factor P of the possibility of moraine lake outburst debris flow, an evaluation standard is formulated, and the possibility of debris flow is judged according to the evaluation standard.

[0013] The evaluation criteria are: , the possibility of debris flow is high; , the possibility of debris flow; , the possibility of mudslide is small.

[0014] Another technical solution adopted by the present invention is the application of a method for judging the possibility of a debris flow caused by the outburst of a moraine lake. The method for judging the possibility of a debris flow caused by the outburst of a moraine lake is suitable for judging the possibility of a debris flow caused by the outburst of a moraine lake in debris flow prevention and control and water conservancy projects.

[0015] The beneficial effects of the present invention are: The method for judging the possibility of debris flow caused by moraine lake burst and its application provided by the present invention aims at the mechanism of debris flow caused by moraine lake burst and analyzes and makes a comprehensive judgment according to the three major conditions for forming debris flow, so as to effectively determine the possibility of debris flow caused by moraine lake burst, and greatly improve the accuracy of the result of judging the possibility of debris flow; the peak flow of moraine lake burst is the key to forming debris flow and also the water source condition for forming debris flow, and firstly calculates the peak flow of moraine lake burst, which provides an important basis for correctly judging the possibility of debris flow caused by moraine lake burst, and makes the final judgment more reliable; fully considering the material source condition for forming debris flow is a key factor, and the outburst of moraine lake without material source is a mountain torrent instead of a debris flow. The solidity coefficient of the regional lithology that forms the source is used to judge the amount of the source and the source particle size, and further judge the possibility of debris flow formation, making the judgment result more applicable; the important influence of terrain conditions on the formation of debris flow caused by the outburst of moraine lake is fully considered, and the average longitudinal gradient (average channel slope) and average channel width of the downstream channel of the moraine lake are used as terrain judgment parameters for the formation of debris flow, making the judgment of the possibility of debris flow more reasonable and reliable; considering that the excessively small channel slope downstream of the moraine lake will cause the debris flow (if a short-term debris flow can be formed) to accumulate rapidly, even if the peak flow is large, the source is sufficient and the source particle size is small, it will cause a large amount of siltation in the channel and ultimately only form a mountain torrent in the middle and lower reaches; the judgment factor P is a dimensionless factor, which is not affected by the scale of different moraine lake areas, channel width downstream of the moraine lake, longitudinal gradient and lithology of the source, and is more applicable. DETAILED DESCRIPTION

[0016] The present invention is described in detail below in conjunction with specific implementation modes.

[0017] The method for judging the possibility of a mud-rock flow formed by a moraine lake outburst provided by the present invention comprises the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; The calculation process of the average longitudinal gradient drop J in the downstream channel of the moraine lake in S1 is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake; The calculation process of the peak discharge Q of the moraine lake outburst in S1 is as follows: Calculate according to formula (2); (2); Where A is the area of ​​moraine lake, unit: m 2 ; Q is the peak flow of moraine lake outburst flood, unit: m 3 / s; The calculation process of the characteristic value D of the source particle size in the downstream watershed of the moraine lake outburst in S1 is as follows: Calculate according to formula (3); (3); Among them, F0 is the solidity coefficient of rock properties, which can be queried according to the solidity coefficient table; D is the characteristic value of the source particle size in the downstream basin of the moraine lake outburst, unit: m; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; The specific process of S2 is as follows: according to the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate of the moraine lake outburst flood Q, the characteristic value of the source particle size D of the downstream basin of the moraine lake outburst, and the average width W of the channel downstream of the moraine lake, the possibility evaluation factor P of the glacial lake outburst debris flow is calculated according to formula (4); (4); Where g is the acceleration due to gravity, unit: m / s 2 ; W is the average width of the channel downstream of the moraine lake, unit: m; S3. Determine the possibility of debris flow based on the probability evaluation factor P of the moraine lake outburst debris flow; The specific process of S3 is as follows: according to the evaluation factor P of the possibility of moraine lake outburst debris flow, an evaluation standard is formulated, and the possibility of debris flow is judged according to the evaluation standard; The evaluation criteria are: , the possibility of debris flow is high; , the possibility of debris flow; , the possibility of mudslide is small.

[0018] The basic principle is as follows: Moraine lake outbursts often further induce debris flows, but they do not necessarily form debris flows. First, the flood flow of moraine lake outbursts is large, providing sufficient water sources for the formation of debris flows; second, there must be sufficient material sources to form debris flows; finally, there must be certain terrain conditions to allow the debris flows to continue to move downstream, rather than just silting up immediately after forming.

[0019] Water source, material source, topography and other conditions are the three major conditions for the formation of debris flow, but these conditions do not affect the formation of debris flow in isolation, but are interrelated and mutually influential, and eventually form debris flow. Although the peak flow of moraine lake burst is very large, it will be weakened in the wide downstream channel, resulting in a smaller single-width flow and flow rate, which makes it difficult to start the channel material source to form debris flow; similarly, if the channel material source particles are large, the single-width flow or flow rate after the moraine lake burst is not enough to start these material sources, and debris flow will not form. The particle size of debris flow material source comes from the collapse or landslide in the area. Hard rocks with a large firmness coefficient F0 often collapse, making the material source in the area not only less, but also the particle size of the material source particles is large, making it relatively difficult to form debris flow; soft rocks with a small firmness coefficient F0 often landslide, making the material source in the area not only more, but also the particle size of the material source particles is small, making it relatively easy to form debris flow.

[0020] Another factor that affects the formation of debris flow is topography. For the characteristic of debris flow formed by the outburst of moraine lake, the topographic factor is the longitudinal gradient and width of the channel downstream of moraine lake: if the longitudinal gradient is too small, even if a debris flow is formed briefly, it will cause siltation due to the small longitudinal gradient; when the longitudinal gradient is large, the debris flow will move all the way downstream to the mouth of the main river. At the same time, because the downstream channel is wide, it will also have a huge impact on the formation of debris flow: the wider the channel, the debris flow is dispersed, and it is more likely to silt up when the longitudinal gradient of the channel is small; on the contrary, it is less likely to silt up when the channel is narrow. Because the channel downstream of moraine lake is generally a wider channel, because the basin area is large, and the long-term glacial erosion forms a wide "U"-shaped valley, the downstream channel needs a larger average slope for debris flow to occur.

[0021] Example 1 The method for determining the possibility of a mudslide caused by a moraine lake outburst proposed in this embodiment includes the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; S3. Determine the possibility of debris flow based on the possibility evaluation factor P of moraine lake outburst debris flow.

[0022] Example 2 The method for determining the possibility of a mudslide caused by a moraine lake outburst proposed in this embodiment includes the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; The calculation process of the average longitudinal gradient drop J in the downstream channel of the moraine lake in S1 is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; S3. Determine the possibility of debris flow based on the possibility evaluation factor P of moraine lake outburst debris flow.

[0023] Example 3 The method for determining the possibility of a mudslide caused by a moraine lake outburst proposed in this embodiment includes the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; The calculation process of the average longitudinal gradient drop J in the downstream channel of the moraine lake in S1 is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake; The calculation process of the peak discharge Q of the moraine lake outburst in S1 is as follows: Calculate according to formula (2); (2); Where A is the area of ​​moraine lake, unit: m 2 ; Q is the peak flow of moraine lake outburst flood, unit: m 3 / s; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; S3. Determine the possibility of debris flow based on the possibility evaluation factor P of moraine lake outburst debris flow.

[0024] Example 4 The method for determining the possibility of a mudslide caused by a moraine lake outburst proposed in this embodiment includes the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; The calculation process of the average longitudinal gradient drop J in the downstream channel of the moraine lake in S1 is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake; The calculation process of the peak discharge Q of the moraine lake outburst in S1 is as follows: Calculate according to formula (2); (2); Where A is the area of ​​moraine lake, unit: m 2 ; Q is the peak flow of moraine lake outburst flood, unit: m 3 / s; The calculation process of the characteristic value D of the source particle size in the downstream watershed of the moraine lake outburst in S1 is as follows: Calculate according to formula (3); (3); Among them, F0 is the solidity coefficient of rock properties, which can be queried according to the solidity coefficient table; D is the characteristic value of the source particle size in the downstream basin of the moraine lake outburst, unit: m; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; S3. Determine the possibility of debris flow based on the possibility evaluation factor P of moraine lake outburst debris flow.

[0025] Example 5 The method for determining the possibility of a mudslide caused by a moraine lake outburst proposed in this embodiment includes the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; The calculation process of the average longitudinal gradient drop J in the downstream channel of the moraine lake in S1 is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake; The calculation process of the peak discharge Q of the moraine lake outburst in S1 is as follows: Calculate according to formula (2); (2); Where A is the area of ​​moraine lake, unit: m 2 ; Q is the peak flow of moraine lake outburst flood, unit: m 3 / s; The calculation process of the characteristic value D of the source particle size in the downstream watershed of the moraine lake outburst in S1 is as follows: Calculate according to formula (3); (3); Among them, F0 is the solidity coefficient of rock properties, which can be queried according to the solidity coefficient table; D is the characteristic value of the source particle size in the downstream basin of the moraine lake outburst, unit: m; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; The specific process of S2 is as follows: according to the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate of the moraine lake outburst flood Q, the characteristic value of the source particle size D of the downstream basin of the moraine lake outburst, and the average width W of the channel downstream of the moraine lake, the possibility evaluation factor P of the glacial lake outburst debris flow is calculated according to formula (4); (4); Where g is the acceleration due to gravity, unit: m / s 2 ; W is the average width of the channel downstream of the moraine lake, unit: m; S3. Determine the possibility of debris flow based on the possibility evaluation factor P of moraine lake outburst debris flow.

[0026] Example 6 The method for determining the possibility of a mudslide caused by a moraine lake outburst proposed in this embodiment includes the following steps: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; The calculation process of the average longitudinal gradient drop J in the downstream channel of the moraine lake in S1 is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake; The calculation process of the peak discharge Q of the moraine lake outburst in S1 is as follows: Calculate according to formula (2); (2); Where A is the area of ​​moraine lake, unit: m 2 ; Q is the peak flow of moraine lake outburst flood, unit: m 3 / s; The calculation process of the characteristic value D of the source particle size in the downstream watershed of the moraine lake outburst in S1 is as follows: Calculate according to formula (3); (3); Among them, F0 is the solidity coefficient of rock properties, which can be queried according to the solidity coefficient table; D is the characteristic value of the source particle size in the downstream basin of the moraine lake outburst, unit: m; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; The specific process of S2 is as follows: according to the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate of the moraine lake outburst flood Q, the characteristic value of the source particle size D of the downstream basin of the moraine lake outburst, and the average width W of the channel downstream of the moraine lake, the possibility evaluation factor P of the glacial lake outburst debris flow is calculated according to formula (4); (4); Where g is the acceleration due to gravity, unit: m / s 2 ; W is the average width of the channel downstream of the moraine lake, unit: m; S3. Determine the possibility of debris flow based on the probability evaluation factor P of the moraine lake outburst debris flow; The specific process of S3 is as follows: according to the evaluation factor P of the possibility of moraine lake outburst debris flow, an evaluation standard is formulated, and the possibility of debris flow is judged according to the evaluation standard; The evaluation criteria are: , the possibility of debris flow is high; , the possibility of debris flow; , the possibility of mudslide is small.

[0027] Example 7 The method for determining the possibility of a mudslide caused by a moraine lake outburst proposed in this embodiment includes the following steps: Since the 20th century, there have been 69 glacial lake outburst incidents in the Himalayas, of which 47 occurred in China and 22 occurred abroad. There have been 38 moraine lake outburst incidents caused by ice avalanches, accounting for 55.9% of all glacial lake outburst incidents, of which 28 occurred in China and 10 occurred abroad. There have been 9 moraine lake outburst incidents caused by ice avalanches with detailed documentation, of which 7 occurred in China and 2 occurred abroad. S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; The calculation process of the average longitudinal gradient J of the downstream channel of the moraine lake is as follows: Calculate according to formula (1); (1); in, is the average slope of the channel downstream of Moraine Lake; The calculation process of the peak discharge Q of the moraine lake outburst flood is as follows: Calculate according to formula (2); (2); Where A is the area of ​​moraine lake, unit: m 2 ; The calculation process of the characteristic value D of the source particle size in the downstream watershed of moraine lake outburst is as follows: Calculate according to formula (3); (3); Among them, F0 is the solidity coefficient of rock properties, which can be queried according to the solidity coefficient table 1; Table 1 Table of strength coefficients

[0028] S2. Calculate the probability assessment factor P of moraine lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of moraine lake, the peak flow of moraine lake outburst Q and the characteristic value D of the source particle size in the downstream watershed of moraine lake outburst; The specific process is as follows: according to the average longitudinal gradient J of the downstream channel of the moraine lake, the peak flow rate Q of the moraine lake outburst flood and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, the possibility evaluation factor P of the glacial lake outburst debris flow is calculated according to formula (4); (4); Where g is the acceleration due to gravity, unit: m / s 2 ; S3. Determine the possibility of debris flow based on the probability evaluation factor P of the moraine lake outburst debris flow; The specific process is as follows: according to the evaluation factor P of the possibility of moraine lake outburst debris flow, an evaluation standard is formulated, and the possibility of debris flow is judged according to the evaluation standard; The evaluation criteria are: , the possibility of debris flow is high; , the possibility of debris flow; , the possibility of debris flow is small, as shown in Table 2; Table 2 The possibility of debris flow caused by moraine lake outburst

[0029] The possibility of debris flow is determined by the glacial lake outburst debris flow possibility evaluation factor P. , the possibility of debris flow is high; , the possibility of debris flow; , the possibility of debris flow is small. As shown in Table 2, among the 8 debris flow events, the possibility of debris flow was judged to be high in 7 cases, accounting for 87.5%; the possibility was medium in one case, accounting for 12.5%; and there was no debris flow in one case, which was judged to be medium.

[0030] In summary, the present invention has a high accuracy in judging the possibility of debris flow after glacial lake outburst.

[0031] Example 8 The application of the method for judging the possibility of debris flow caused by the outburst of a moraine lake proposed in this embodiment adopts the above-mentioned method for judging the possibility of debris flow caused by the outburst of a moraine lake, and is suitable for judging the possibility of debris flow caused by the outburst of a moraine lake in debris flow prevention and control and water conservancy projects.

Claims

1. A method for determining the possibility of a moraine lake bursting to form a debris flow, characterized in that: The following steps are involved: S1. Calculate the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate Q of the moraine lake outburst and the characteristic value D of the source particle size in the downstream basin of the moraine lake outburst, and measure the average width W of the channel downstream of the moraine lake; S2. Calculate the probability assessment factor P of glacial lake outburst debris flow according to the average longitudinal gradient J of the downstream channel of glacial lake, the peak flow of glacial lake outburst Q, the characteristic value of source particle size D in the downstream basin of glacial lake outburst and the average width W of the downstream channel of glacial lake; S3. Determine the possibility of debris flow based on the possibility evaluation factor P of moraine lake outburst debris flow.

2. The method for determining the possibility of a moraine lake outburst forming a debris flow according to claim 1, characterized in that: The calculation process of the average longitudinal gradient drop J of the downstream channel of the moraine lake described in S1 is as follows: Calculate according to formula (1); （1）； in, is the average slope of the channel downstream of Moraine Lake.

3. The method for determining the possibility of a mudslide caused by a moraine lake outburst according to claim 1, characterized in that: The calculation process of the moraine lake outburst peak flow Q described in S1 is as follows: Calculate according to formula (2); （2）； Where A is the area of ​​moraine lake, unit: m 2 ; Q is the peak flow of moraine lake outburst flood, unit: m 3 / s.

4. The method for determining the possibility of a mudslide caused by a moraine lake outburst according to claim 1, characterized in that: The calculation process of the characteristic value D of the source particle size in the downstream watershed of the moraine lake outburst described in S1 is as follows: Calculate according to formula (3); （3）； Among them, F0 is the solidity coefficient of rock properties, which is queried according to the solidity coefficient table; D is the characteristic value of the source particle size in the downstream basin of the moraine lake outburst, unit: m.

5. The method for determining the possibility of a mudslide caused by a moraine lake outburst according to claim 1, characterized in that: The specific process of S2 is as follows: according to the average longitudinal gradient J of the channel downstream of the moraine lake, the peak flow rate of the moraine lake outburst flood Q, the characteristic value of the source particle size D of the downstream basin of the moraine lake outburst and the average width W of the channel downstream of the moraine lake, the possibility evaluation factor P of the glacial lake outburst debris flow is calculated according to formula (4); （4）； Where g is the acceleration due to gravity, unit: m / s 2 ; W is the average width of the channel downstream of the moraine lake, unit: m.

6. The method for determining the possibility of a mudslide caused by a moraine lake outburst according to claim 1, characterized in that: The specific process of S3 is: according to the moraine lake outburst debris flow possibility evaluation factor P, an evaluation standard is formulated, and the possibility of debris flow occurrence is judged according to the evaluation standard.

7. The method for determining the possibility of a mudslide caused by a moraine lake outburst according to claim 6, characterized in that: The evaluation criteria are: , the possibility of debris flow is high; , the possibility of debris flow; , the possibility of mudslide is small.

8. The application of the method for determining the possibility of debris flow caused by the outburst of moraine lake is characterized by: The method for judging the possibility of a debris flow caused by the outburst of a moraine lake as claimed in any one of claims 1 to 7 is applicable to judging the possibility of a debris flow caused by the outburst of a moraine lake in debris flow prevention and control and water conservancy projects.

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