An emergency safety disposal method suitable for high-risk barrier lake in harsh environment

Abstract

The application provides an emergency safety disposal method for high-risk dammed lake in harsh environment. The emergency safety disposal method comprises the following steps: excavating a first-stage diversion open channel; when the water level of the dammed lake rises to the water entering the first-stage diversion open channel, adjusting the height of the first water passing cofferdam to make the flow rate of the first-stage diversion open channel less than the allowable safe flow rate; during the period of the water of the dammed lake being diverted through the first-stage diversion open channel, excavating multiple second-stage diversion open channels on one side of the first-stage diversion open channel, and immediately using the second-stage diversion open channels to divert the water of the dammed lake after the completion of the second-stage diversion open channels; adjusting the height of the second water passing cofferdam to make the flow rate of the second-stage diversion open channel less than the allowable safe flow rate, and adjusting the height of the first water passing cofferdam to make the flow rate of the first-stage diversion open channel less than the allowable safe flow rate. The safety disposal process needs to continue until the dry season comes, and the water of the dammed lake falls back, and the dammed body can be removed layer by layer.

Description

Technical Field

[0001] This application relates to the fields of geological disaster and water conservancy engineering technology, and in particular to an emergency safety management method for high-risk landslide dammed lakes applicable to harsh environments. Background Technology

[0002] High-risk landslide dammed lakes are mostly caused by landslides triggered by natural disasters such as strong earthquakes, continuous heavy rainfall, or rainstorms, which block river channels and cause the flow of water. The landslide dam is huge, and the water volume and water level of the landslide dammed lake rise rapidly. The failure of the landslide dam (dam) will cause serious secondary disasters and pose a serious threat to the ecological environment along the river and the lives and property of the people.

[0003] The handling of high-risk landslide dammed lakes in recent decades may exacerbate disaster risks due to untimely emergency response, improper handling methods, or uncontrolled collapse of the landslide dam, making it difficult to meet the safety handling needs of high-risk landslide dammed lakes in complex environments. Summary of the Invention

[0004] This application provides an emergency safety response method for high-risk landslide dammed lakes applicable to harsh environments, the emergency safety response method comprising: When a high-risk landslide dammed lake occurs, the water body of the landslide dammed lake is obtained and the water body is used to treat the slope and seepage of the landslide dam. Before the water level of the landslide dammed lake reaches the pass of the landslide dam, a first-stage diversion channel is excavated at the pass, and a first water-passing cofferdam is set at the end of the first-stage diversion channel facing the landslide dammed lake; one end of the first-stage diversion channel is connected to the landslide dammed lake, and the other end is connected to the downstream river channel; When the water level of the landslide dammed lake rises until the water enters the first-phase diversion channel, the height of the first water-passing cofferdam is adjusted so that the flow velocity in the first-phase diversion channel is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth. During the period when the water of the landslide dammed lake is diverted through the first-phase diversion channel, multiple second-phase diversion channels are excavated sequentially on at least one side of the first-phase diversion channel, and a second cofferdam is set at the end of each second-phase diversion channel facing the landslide dammed lake; each second-phase diversion channel is immediately used to divert water from the landslide dammed lake after its construction is completed, so as to increase the total diversion flow of water from the landslide dammed lake; one end of the second-phase diversion channel is connected to the landslide dammed lake, and the other end is connected to the downstream river channel; the bottom height of the second-phase diversion channel is greater than the bottom height of the first-phase diversion channel; From the direction of the first-phase diversion channel to the second-phase diversion channel, the bottom height of the plurality of second-phase diversion channels increases sequentially; for each second-phase diversion channel, when the water level of the landslide dam rises until the water enters the second-phase diversion channel, the height of the second water-passing cofferdam is adjusted so that the flow velocity in the second-phase diversion channel is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth, and at the same time, the height of the first water-passing cofferdam is adjusted so that the flow velocity in the first-phase diversion channel is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth; The water in the landslide dammed lake is guided to the downstream river channel using the first-phase diversion channel and the second-phase diversion channel.

[0005] In some embodiments, during the period when the water of the landslide dammed lake is diverted through the first-stage diversion channel, a plurality of second-stage diversion channels are sequentially excavated on at least one side of the first-stage diversion channel, including: Excavate a second-phase diversion channel adjacent to the first-phase diversion channel; for each second-phase diversion channel located on the same side as the first-phase diversion channel, while the second-phase diversion channel closer to the first-phase diversion channel is used to divert the water of the landslide dammed lake, excavate an adjacent second-phase diversion channel on the side of the second-phase diversion channel closer to the first-phase diversion channel that is away from the first-phase diversion channel.

[0006] In some embodiments, after setting up a first water-passing cofferdam at the end of the first-phase diversion channel facing the landslide dammed lake, the emergency response method further includes: The water in the landslide dammed lake was guided into the first-phase diversion channel for testing, and the maximum allowable flow velocity and maximum allowable flow depth of the first-phase diversion channel were measured. After testing the first phase of the diversion channel, the water from the landslide dammed lake was diverted into the first phase of the diversion channel for discharge.

[0007] In some embodiments, the first-phase diversion channel includes an inlet section, a weir crest section, and a spillway section connected in sequence; the inlet section is connected to the landslide dammed lake, and the spillway section is connected to the downstream river channel; the first water-passing cofferdam is set in the inlet section; The measurements obtained for the maximum permissible flow velocity and maximum permissible flow depth of the first-phase diversion channel include: The maximum allowable flow velocity and the maximum allowable flow depth of the weir crest section and the spillway section are measured respectively; the smaller of the maximum allowable flow velocity of the weir crest section and the spillway section is taken as the maximum allowable flow velocity of the first-phase diversion channel; the smaller of the maximum allowable flow depth of the weir crest section and the spillway section is taken as the maximum allowable flow depth of the first-phase diversion channel.

[0008] In some embodiments, the first-phase diversion channel and the second-phase diversion channel include an inlet section, a weir crest section, and a spillway section connected in sequence; the inlet section is connected to the landslide dammed lake, and the spillway section is connected to the downstream river channel; the bottom surface of the inlet section is horizontal, and the bottom surfaces of the weir crest section and the spillway section are inclined, and the bottom slope of the spillway section is greater than or equal to the bottom slope of the weir crest section; The inlet section is used to guide the water of the landslide dammed lake into the crest channel section, and the spillway section is used to guide the water flow of the crest channel section to the downstream river channel.

[0009] In some embodiments, the bottom surfaces of the inlet section, the weir crest section, and the spillway section are all provided with bottom protection, and the slopes of the inlet section, the weir crest section, and the spillway section are all provided with slope protection or retaining walls.

[0010] In some embodiments, the first water-passing cofferdam is disposed at the inlet section of the first-phase diversion channel, and the second water-passing cofferdam is disposed at the inlet section of the second-phase diversion channel; Before the water level of the landslide dammed lake rises until the water enters the first-phase diversion channel, the emergency safety handling method further includes: setting a first stilling sill at the connection between the inlet section of the first-phase diversion channel and the crest section of the first-phase diversion channel; Before the diversion channel is used to divert the water from the landslide dammed lake, the emergency safety handling method further includes: setting a second stilling sill at the connection between the inlet section of the second-phase diversion channel and the crest section of the second-phase diversion channel.

[0011] In some embodiments, before the water level of the landslide dammed lake rises until the water enters the first-phase diversion channel, the emergency safety handling method further includes: setting a first toothed wall at the connection between the inlet section of the first-phase diversion channel and the downstream river channel; Before the diversion channel is used to divert the water from the landslide dammed lake, the emergency safety treatment method further includes: setting a second toothed wall at the connection between the spillway section of the second-phase diversion channel and the downstream river channel.

[0012] In some embodiments, the first water-passing cofferdam includes a first sub-cofferdam body that is widened and heightened by layered masonry, and the second water-passing cofferdam includes a second sub-cofferdam body that is widened and heightened by layered masonry. Adjusting the height of the first water-passing cofferdam to make the flow velocity in the first phase diversion channel less than the maximum allowable flow velocity and the flow depth less than the maximum allowable flow depth includes: as the water level of the landslide dam lake rises, constructing a wider and higher first sub-weir body in layers on the top of the first water-passing cofferdam to increase the height of the first water-passing cofferdam. Adjusting the height of the second water-passing cofferdam to make the flow velocity in the second-phase diversion channel less than the maximum allowable flow velocity and the flow depth less than the maximum allowable flow depth includes: as the water level of the landslide dam lake rises, constructing a wider and higher second sub-cofferdam in layers on top of the second water-passing cofferdam to increase the height of the second water-passing cofferdam.

[0013] In some embodiments, the emergency safety response method further includes: After the water level of the landslide dammed lake stops rising, the excavation of the second-phase diversion channel shall be stopped; after the landslide dammed lake enters the dry season and the water level of the landslide dammed lake drops, the first and second water-passing cofferdams shall be dismantled layer by layer. The landslide dam can be dismantled and the river channel restored, or the landslide dam can be converted into a long-term usable dam.

[0014] The emergency safety management method for high-risk landslide-dammed lakes in harsh environments provided in this application embodiment involves the initial deployment of a first-phase diversion channel. This allows for early flood discharge, effectively reducing the rate of water level rise in the landslide-dammed lake and providing sufficient time for the subsequent excavation of a second-phase diversion channel. Once the second-phase diversion channel is operational, it alleviates the flood discharge pressure on the first-phase channel, increases the overall flow rate of the diversion channel, and ensures the stability of the landslide-dammed structure. Furthermore, the first and second cofferdams allow for dynamic regulation of the water volume entering the diversion channel, controlling the impact intensity of the water flow on the landslide-dammed body and ensuring its stability and the safety of the diversion process.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this specification and, together with the description, serve to explain the principles of this specification.

[0017] Figure 1 A flowchart illustrating an emergency safety response method for high-risk landslide dammed lakes in harsh environments, provided as an embodiment of this application; Figure 2 A schematic diagram of the cross-sectional structure of a high-risk landslide dammed lake provided in an embodiment of this application; Figure 3 A schematic diagram of the plan layout of the first-phase diversion channel and the second-phase diversion channel provided in an embodiment of this application; Figure 4 for Figure 3 The illustrated embodiment provides a longitudinal sectional structural diagram of the first-phase diversion channel and the second-phase diversion channel; Figure 5 for Figure 3 The illustrated embodiment provides a schematic diagram of the cross-sectional structure of the first-phase diversion channel and the second-phase diversion channel; Figure 6 A flowchart of an emergency safety handling method for high-risk landslide dammed lakes in harsh environments, provided as another embodiment of this application. Detailed Implementation

[0018] The technical solutions in the embodiments (or "implementations") of this application will be clearly and completely described herein with reference to the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0019] If the embodiments of this application contain terms relating to directional indications or positional relationships (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationships and movement of the components in a specific posture (as shown in the attached figures); if the specific posture changes, the directional indications or positional relationships will also change accordingly. Furthermore, the terms "first" and "second" used in the embodiments of this application are only for descriptive convenience and should not be construed as indicating or implying relative importance.

[0020] The following description, in conjunction with the accompanying drawings, details an emergency safety management method for high-risk landslide dammed lakes in harsh environments, according to an embodiment of this application. Unless otherwise specified, the following embodiments and features can complement or combine with each other.

[0021] This application provides an emergency safety management method for landslide dammed lakes, such as... Figure 1 As shown, emergency response methods include: Step S100: Quickly initiate land, air, and water transportation to reach the landslide dam site.

[0022] By adapting to local conditions and changing circumstances, we skillfully utilized the water body of the landslide dam to generate powerful hydraulic excavation capabilities, and promptly deployed resources to address dangerous slopes and potential seepage hazards of the landslide dam.

[0023] Step S200: Excavate and repair the first-phase diversion channel 21 at the pass 111, and reinforce it. The first-phase diversion channel includes: the inlet section 231 connected to the landslide dam, the dam crest channel section 232 at the top of the landslide dam, and the spillway section 233 on the downstream slope of the landslide dam, which connects to the downstream river channel 60, forming a safe passage for the water from the landslide dam to be discharged into the downstream river channel.

[0024] Step S300: As Figure 3 and Figure 4 As shown, when the water level of the landslide dammed lake 10 rises and enters the first-phase diversion channel 21, the first water-passing cofferdam 31, which is pre-set on the inlet section 231, protects the landslide dammed lake water level from rising safely, and controls the flow of the landslide dammed lake water into the dam crest channel section 232 and the spillway section 233 to be less than the allowable flow, thus ensuring the safe operation of the diversion channel.

[0025] Step S400: As Figures 3 to 5 As shown, during the period when the water from landslide dammed lake 10 is being diverted into the first-phase diversion channel 21, the second-phase diversion channel 22 must be repaired and put into operation in a timely manner to increase the total diversion flow and slow down the rate of water level rise in landslide dammed lake 10. This process must continue until the dry season arrives.

[0026] Step S500: As the dry season begins, the water level of landslide dammed lake 10 stops rising or recedes. This allows for the cessation of the diversion channel expansion and the gradual removal of the cofferdam layer by layer, lowering the water level of the landslide dammed lake to the bottom elevation of the first-phase diversion channel. At this point, the emergency safety management of the high-risk landslide dammed lake is complete.

[0027] Step S600: As for the final disposal of the landslide dam, it should be determined according to the needs of the comprehensive watershed planning, either by dismantling the landslide dam and restoring the original state of the river channel, or by building the landslide dam into a permanent dam.

[0028] Step S100 is to take swift emergency action in the event of a high-risk landslide dammed lake in adverse environmental conditions.

[0029] When land transportation is insufficient to meet emergency rescue needs in the short term, conventional air transport can be used for rapid emergency response. Rescue personnel, emergency supplies, and lightweight, practical equipment can be quickly transported to the landslide dam site via airdrop, and on-site surveys and risk assessments can be conducted immediately. Adapting to local conditions and the specific circumstances, the water body of the landslide dam should be utilized to create a powerful hydraulic excavation force, which can be promptly deployed to address dangerous slopes and seepage hazards of the dam.

[0030] In situations where land transportation cannot directly reach the site of landslide dam 10, while air transport is the preferred emergency delivery option, it is crucial to pay close attention to the current state of road traffic around the landslide dam 10 area and simultaneously advance the emergency repair work on temporary roads leading to the lake area. This will allow for the full utilization of the water surface of landslide dam 10 to construct an emergency rescue channel, enabling the efficient transport of personnel, materials, and equipment to landslide dam 11 via water transport.

[0031] Specifically, a floating platform can be constructed on the landslide dam 10. This platform provides stable support for the installation and securing of water pump units, the laying of water pipelines, and the operation of construction personnel. Water pump units on the platform will draw water from the landslide dam 10 to create the high-pressure water flow required for hydraulic excavation. The powerful impact of this water flow will be used to strip away the loose soil and rock from the landslide dam 11. During the hydraulic excavation process, dangerous slopes and potential leakage hazards on the landslide dam 11 will be addressed safely.

[0032] In one embodiment, in step S200, as Figure 2 As shown, the first-phase diversion channel 21 was excavated at the pass 111, including: before the water level of the landslide dammed lake reaches the pass of the landslide dammed body, the water of the landslide dammed lake 10 was pumped out to form a powerful hydraulic excavation force, and earthmoving machinery and equipment were used to efficiently repair the first-phase diversion channel 21, so as to meet the conditions for diverting and draining the water of the landslide dammed lake as soon as possible.

[0033] In one embodiment, such as Figure 3 and Figure 4 As shown, the first-phase diversion channel 21 includes an inlet section 231, a weir crest section 232, and a spillway section 233 connected in sequence. The inlet section 231 connects to the landslide dammed lake 10, and the spillway section 233 connects to the downstream river channel 60. The bottom of the inlet section 231 is horizontal, the bottom of the weir crest section 232 has a gentle slope, and the bottom of the spillway section 233 has a steep slope. The inlet section 231 guides the water from the landslide dammed lake 10 into the weir crest section 232, and the spillway section 233 guides the water flow from the weir crest section 232 to the downstream river channel 60.

[0034] Specifically, the bottom surfaces of the inlet section 231, the weir crest section 232, and the spillway section 233 are all equipped with bottom protection, and the slopes or sidewalls of the inlet section 231, the weir crest section 232, and the spillway section 233 are all equipped with slope protection or retaining walls. The bottom protection, slope protection, or retaining walls can improve the ability of the dam body 11 to resist water erosion, ensure the structural stability of each channel section, and maintain a safe and reliable discharge capacity for each channel section.

[0035] Specifically, the bottom and slope protection of each canal section adopts a geotextile concrete structure, with the concrete thickness controlled at 30mm or less. During concrete mixing, the sand and gravel collected during the hydraulic excavation of the landslide dam can be used directly as raw materials, making full use of local resources.

[0036] It should be proposed that a composite protection structure of steel pipe mesh and geotextile concrete bedding be adopted for spillway section 233. During construction, steel pipe columns can be installed at 1m x 1m intervals, with the steel pipe columns embedded into the slope to a depth of not less than 1m and the height of the columns protruding from the slope surface being 1m to 1.5m. A bottom layer of steel pipe mesh is erected based on these columns, and a 1m thick layer of geotextile concrete bedding is laid on top of the bottom layer of steel pipe mesh. An upper layer of steel pipe columns is then erected on top of the geotextile concrete bedding, and an upper layer of steel pipe mesh is also erected. The upper layer of steel pipe mesh is used to press the surface of the geotextile concrete bedding, ultimately forming the bottom and slope protection structure for spillway section 233.

[0037] The spacing of the steel pipe columns, the depth of their embedment into the slope, the height of their protrusion from the slope, and the thickness of the concrete in the formwork can all be specifically set according to actual needs.

[0038] It should be noted that a toothed wall is installed at the connection between the end of the spillway section 232 and the downstream river channel 60 to ensure the safe operation of the spillway section 232.

[0039] In step S300, as Figure 3 , Figure 4 and Figure 5 As shown, when the water level of the landslide dammed lake 10 rises and enters the first-phase diversion channel 21, a cofferdam pre-installed on the inlet section 231 serves two purposes: firstly, it safely resists the continuous rise in the water level of the landslide dammed lake; secondly, it regulates the flow velocity and depth of the water passing through the cofferdam. The diversion flow rate entering the crest channel section 232 and the spillway section 233 is dynamically controlled to be less than the allowable flow rate, ensuring the safe operation of the diversion channel.

[0040] Specifically, the first phase of the diversion channel will undergo trial operation in the initial stage of flow passage (the planned weir crest water passage depth is ≤0.6m and the water passage width is ≤10m) to ensure the safety of the trial operation.

[0041] By testing the maximum unit width flow rate (including flow velocity and flow depth) of the weir crest section and the spillway section respectively during trial operation, the smaller of the two values ​​is taken, and the safety factor is considered to determine the allowable unit width flow rate and allowable flow depth of the cofferdam.

[0042] After trial operation and testing, the first phase of the diversion channel has entered normal diversion operation under the strict control of the cofferdam.

[0043] It should be emphasized that as the water level of the landslide dam lake rises and the cofferdam is raised to a certain height, an energy dissipation sill 41 needs to be set up at an appropriate location downstream to form an energy dissipation pool, which will facilitate the smooth flow of water over the dam into the canal on the top of the dam.

[0044] In step S400, during the operation of the first phase diversion channel, the second phase diversion channel should be repaired without delay and put into operation in a timely manner to continuously increase the total flow of water from the landslide dammed lake.

[0045] In one embodiment, the cofferdam is gradually raised as the water level of the landslide dam lake rises. To accommodate the cofferdam's gradual increase in height while moving through the water, the cofferdam is constructed using square concrete ton bags (length × width × height = 500mm × 500mm × 500mm).

[0046] It should be emphasized that the second phase of the diversion channel 22 should be repaired according to the actual situation on site, but it is not limited to the second phase of the diversion channel. This process should continue until the dry season.

[0047] In step S500: As the dry season begins, the water level of the landslide dammed lake 10 stops rising or recedes. This not only halts the expansion of the diversion channel but also allows for the gradual removal of the cofferdam layer by layer, lowering the water level of the landslide dammed lake to the bottom elevation of the first-phase diversion channel. At this point, the emergency safety management of the high-risk landslide dammed lake is complete.

[0048] In step S600: As for the final disposal of the landslide dam, it should be determined according to the needs of the comprehensive watershed planning, either by dismantling the landslide dam and restoring the original state of the river channel, or by constructing the landslide dam into a permanent dam.

[0049] This application also provides an emergency safety management method for landslide-dammed lakes, such as... Figure 6 As shown, the emergency safety handling method includes the following steps S710 to S760: Step S710: When a high-risk landslide dammed lake 10 occurs, the water body of the landslide dammed lake 10 is obtained and the water body is used to impact and repair the slope of the landslide dam, and the leakage of the landslide dam is treated.

[0050] Step S720: As Figure 2 and Figure 3 As shown, before the water level of the landslide dammed lake 10 reaches the pass 111 of the landslide dam 11, a first-stage diversion channel 21 is excavated at the pass 111, and a first water-passing cofferdam 31 is set at the end of the first-stage diversion channel 21 facing the landslide dammed lake 10. One end of the first-stage diversion channel 21 is connected to the landslide dammed lake 10, and the other end is connected to the downstream river channel 60.

[0051] Step S730: As Figure 3 and Figure 4 As shown, when the water level of the landslide dammed lake 10 rises until the water enters the first-stage diversion channel 21, the flow velocity in the first-stage diversion channel 21 will be less than the maximum allowable flow velocity and the flow depth will be less than the maximum allowable flow depth by adjusting the height of the first water-passing cofferdam 31.

[0052] Step S740: As Figures 3 to 5 As shown, during the period when the water of the landslide dammed lake 10 is diverted through the first-stage diversion channel 21, multiple second-stage diversion channels 22 are excavated in sequence on at least one side of the first-stage diversion channel 21, and a second water-passing cofferdam 32 is set at the end of each second-stage diversion channel 22 facing the landslide dammed lake 10; each second-stage diversion channel 22 is immediately used to divert the water of the landslide dammed lake 10 after its construction is completed, so as to increase the total diversion flow of the water of the landslide dammed lake 10.

[0053] Step S750: One end of the second-phase diversion channel 22 is connected to the landslide dam 10, and the other end is connected to the downstream river channel 60; the bottom height of the second-phase diversion channel 22 is greater than the bottom height of the first-phase diversion channel 21; from the direction of the first-phase diversion channel 21 to the second-phase diversion channel 22, the bottom height of multiple second-phase diversion channels 22 increases sequentially; for each second-phase diversion channel 22, when the water level of the landslide dam 10 rises until the water enters the second-phase diversion channel 22, the height of the second water-passing cofferdam 32 is adjusted so that the flow velocity in the second-phase diversion channel 22 is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth, and the height of the first water-passing cofferdam 31 is adjusted so that the flow velocity in the first-phase diversion channel 21 is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth.

[0054] Step S760: The water in the landslide dammed lake is diverted to the downstream river channel using the first-phase diversion channel 21 and the second-phase diversion channel 22. This safety procedure will continue until the dry season arrives, during which time the water level in the landslide dammed lake will recede, and the dammed structure can be dismantled layer by layer.

[0055] Before the water level of the landslide dam 10 reaches the lowest point of the landslide dam 11, the first-phase diversion channel 21 is excavated in advance, utilizing the topographical advantages of the pass 111 to construct a preliminary flood discharge channel. Once the water enters the first-phase diversion channel 21, the flow velocity and depth are controlled by adjusting the height of the first cofferdam 31 to prevent excessive water impact that could cause instability in the landslide dam 11. While utilizing the first-phase diversion channel 21 to discharge water, multiple second-phase diversion channels 22 are excavated. These second-phase diversion channels are put into use as soon as possible after completion, thereby increasing the total flow capacity of the diversion channels and achieving a match between flood discharge capacity and the rising water level trend.

[0056] The emergency response method for landslide dammed lake 10 provided in this application embodiment allows the first-phase diversion channel 21 to be put into operation first, which can play a role in flood discharge in advance, effectively reduce the rate of rise of water level in landslide dammed lake 10, and buy sufficient time for the excavation of the second-phase diversion channel 22.

[0057] If only the first-stage diversion channel 21 is used for flood discharge, when the water level continues to rise to its upper limit, the water will overflow the first-stage diversion channel 21 and directly scour the dam 11. The loose dam 11 will experience a sharp drop in stability after being scour by the high-speed water flow, which may lead to a breach or other dangers. When the second-stage diversion channel 22 is put into operation, it can quickly divert the flood discharge pressure of the first-stage diversion channel 21, increase the overall flow rate, and ensure the stability of the dam 11 structure.

[0058] Furthermore, the first and second cofferdams 31 and 32 can be used to dynamically regulate the amount of water entering the diversion channel, control the impact intensity of the water flow on the dam body 11, and ensure the stability of the dam body 11 and the safety of the diversion process.

[0059] When a high-risk landslide dam forms under harsh conditions, a rapid emergency response should be initiated. When the environment of landslide dam 10 is relatively harsh, land transportation may not be able to meet the emergency rescue needs in the short term. In such cases, air transport can be used to carry out a rapid emergency response. Rescue personnel, emergency supplies, and lightweight and practical equipment can be quickly transported to the site of landslide dam 10 by air, and on-site investigation and risk assessment can be carried out immediately.

[0060] In situations where land transportation cannot directly reach the site of landslide dam 10, while air transport is the preferred emergency delivery option, it is crucial to pay close attention to the current state of road traffic around the landslide dam 10 area and simultaneously advance the emergency repair work on temporary roads leading to the lake area. Furthermore, the water body of landslide dam 10 itself can be fully utilized to construct an emergency rescue channel, enabling the efficient delivery of personnel, materials, and equipment to landslide dam 11 via water transport.

[0061] In one embodiment, a floating platform can be constructed on the landslide dam 10. This platform provides stable support for the installation and securing of water pump units, the laying of water pipelines, and the operation of construction personnel. Water pump units on the platform draw water from the landslide dam 10 to create the high-pressure water flow required for hydraulic excavation. The impact force of this water flow is used to strip loose soil and rocks from the landslide dam 11. During the hydraulic excavation process, the dangerous slopes of the landslide dam 11 are scoured and shaped by the water flow to reduce the risk of slope collapse.

[0062] In one embodiment, such as Figure 2As shown, the first-phase diversion channel 21 was excavated at the pass 111, including: extracting water from the landslide dam 10 using the water resources of the landslide dam 10 and the topographic conditions of the landslide dam 11, using the extracted water to form a powerful hydraulic excavation force, and combining it with earthmoving machinery and equipment to efficiently excavate the first-phase diversion channel 21, which greatly shortened the excavation period of the first-phase diversion channel 21.

[0063] In one embodiment, such as Figure 3 As shown, multiple second-stage diversion channels 22 are excavated sequentially on at least one side of the first-stage diversion channel 21, including: extracting water from the landslide dammed lake 10 and using the extracted water to excavate the second-stage diversion channels 22. This fully utilizes the water resources and topographical conditions of the landslide dammed lake 10 to achieve efficient excavation of the second-stage diversion channels 22, significantly shortening the excavation period.

[0064] In one embodiment, such as Figures 3 to 5 As shown, during the diversion of water from the landslide dammed lake 10 through the first-stage diversion channel 21, multiple second-stage diversion channels 22 are excavated sequentially on at least one side of the first-stage diversion channel 21, including: Excavate a second-phase diversion channel 22 adjacent to the first-phase diversion channel 21. While the second-phase diversion channel 22 near the first-phase diversion channel 21 is used to divert water from the landslide dammed lake 10, excavate an adjacent second-phase diversion channel 22 on the side of the second-phase diversion channel 22 away from the first-phase diversion channel 21.

[0065] The number of the second phase of diversion channels 22 gradually increases with the rise in water level, so that the overall flood discharge capacity matches the rise in water level. This ensures that the previous channel has been playing a stable role in flood discharge and effectively slows down the rise in water level, while taking advantage of the time to expand and excavate outwards, so as to buy enough time for the layout of the outer channel.

[0066] In one embodiment, such as Figure 3 and Figure 4 As shown, the first-phase diversion channel 21 and the second-phase diversion channel 22 include an inlet section 231, a weir crest channel section 232, and a spillway section 233 connected in sequence. The inlet section 231 connects to the landslide dammed lake 10, and the spillway section 233 connects to the downstream river channel 60. The bottom surface of the inlet section 231 is horizontal, while the bottom surfaces of the weir crest channel section 232 and the spillway section 233 are inclined, with the slope of the spillway section 233 being greater than or equal to the slope of the weir crest channel section 232. The inlet section 231 guides the water from the landslide dammed lake 10 into the weir crest channel section 232, and the spillway section 233 guides the water flow from the weir crest channel section 232 to the downstream river channel 60.

[0067] The horizontal inlet section 231 can buffer the impact kinetic energy when the water enters, and avoid local scouring of the channel inlet and the connection between the dam body 11 by the water flow. The inclined setting of the dam crest channel section 232 and the spillway section 233 can ensure that the water of the dammed lake 10 is discharged quickly.

[0068] In one embodiment, the bottom surfaces of the inlet section 231, the weir crest section 232, and the spillway section 233 are all provided with bottom protection, and the sides of the inlet section 231, the weir crest section 232, and the spillway section 233 are all provided with slope protection or retaining walls. Bottom protection, slope protection, or retaining walls can improve the dam body 11's ability to resist water flow impact, ensure the structural stability of each channel section, and enable each channel section to maintain efficient flood discharge capacity.

[0069] Specifically, the bottom and slope protection of each canal section adopts a geotextile concrete structure, with the concrete thickness controlled at 30mm or less. During concrete mixing, the sand and gravel collected during the hydraulic excavation of the landslide dam can be used directly as raw materials, achieving on-site material sourcing and making the best use of resources.

[0070] It should be noted that the spillway section 233 can adopt a composite protection structure of steel pipe mesh and geotextile concrete. During construction, steel pipe columns can be installed at 1m×1m intervals, with the steel pipe columns embedded into the slope to a depth of not less than 1m and the columns protruding from the slope to a height of 1m~1.5m. A bottom layer of steel pipe mesh is erected based on these columns, and a 1m thick geotextile concrete layer is laid above the bottom layer of steel pipe mesh. An upper layer of steel pipe columns is then erected on top of the geotextile concrete, followed by an upper layer of steel pipe mesh. The upper layer of steel pipe mesh is used to press the surface of the geotextile concrete, ultimately forming the bottom or slope protection structure of the spillway section 233.

[0071] The spacing of the steel pipe columns, the depth of their embedment into the slope, the height of their protrusion from the slope, and the thickness of the concrete in the formwork can all be specifically set according to actual needs.

[0072] In one embodiment, such as Figure 3 and Figure 4 As shown, the first water-passing cofferdam 31 is set at the inlet section 231 of the first-stage diversion channel 21, and the second water-passing cofferdam 32 is set at the inlet section 231 of the second-stage diversion channel 22.

[0073] Before the water level of the landslide dammed lake 10 rises and enters the first diversion channel 21, a first stilling sill 41 is set at the connection between the inlet section 231 and the crest section 232 of the first diversion channel 21.

[0074] Before the second-phase diversion channel 22 is used to divert water from the landslide dammed lake 10, a second stilling sill 42 is installed at the connection between the inlet section 231 of the second-phase diversion channel 22 and the crest section 232 of the second-phase diversion channel 22.

[0075] The first and second stilling basins 41 and 42 can significantly reduce the impact intensity of the water flow, avoid the local scouring of the inlet of the weir crest channel 232 and the weir body 11 by the high-speed water flow, and help improve the stability of the first-phase diversion channel 21 and the second-phase diversion channel 22.

[0076] In one embodiment, before the water level of the landslide dam 10 rises and enters the first-phase diversion channel 21, such as Figure 4 As shown, a first toothed wall 51 is set at the connection between the discharge channel section 233 of the first-phase diversion channel 21 and the downstream river channel 60.

[0077] Before the second-phase diversion channel 22 is used to divert water from the landslide dammed lake 10, such as Figure 4 As shown, a second toothed wall 52 is installed at the connection between the discharge channel section 233 of the second-phase diversion channel 22 and the downstream river channel 60.

[0078] The first toothed wall 51 and the second toothed wall 52 can effectively resist the impact of the water flow during the high-speed flood discharge of the spillway section 233, avoid the collapse, scouring and erosion caused by the direct impact of the water flow on the river channel, and allow the discharged water to flow smoothly into the downstream river channel 60.

[0079] In one embodiment, after setting a first water-passing cofferdam 31 at one end of the first-stage diversion channel 21 facing the landslide dammed lake 10, the water in the landslide dammed lake 10 is guided into the first-stage diversion channel 21 for testing, so as to obtain the maximum allowable flow velocity and the maximum allowable flow depth of the first-stage diversion channel 21.

[0080] By controllingly guiding a small amount of water from the landslide dammed lake 10 into the first-phase diversion channel 21, the operating conditions of the first-phase diversion channel 21 under different flow conditions were simulated. During the test, the water flow stability, structural bearing capacity, and stress state of the connection points of each section of the first-phase diversion channel 21 were monitored. Finally, the maximum allowable flow velocity and the maximum allowable flow depth that can ensure the structural safety of the first-phase diversion channel 21 and achieve the maximum flood discharge efficiency were determined.

[0081] After obtaining the maximum allowable flow velocity and maximum allowable flow depth of the first-phase diversion channel 21 through testing, it can be used as a reference to guide the subsequent excavation work of the second-phase diversion channel 22.

[0082] In one embodiment, the maximum values ​​of the allowable flow velocity and the maximum values ​​of the allowable flow depth of the first-stage diversion channel 21 are measured, including: The maximum allowable flow velocity and maximum allowable flow depth of the weir crest section 232 and the spillway section 233 are measured respectively. The smaller of the maximum allowable flow velocity of the weir crest section 232 and the maximum allowable flow velocity of the spillway section 233 is taken as the maximum allowable flow velocity of the first-phase diversion channel 21; the smaller of the maximum allowable flow depth of the weir crest section 232 and the maximum allowable flow depth of the spillway section 233 is taken as the maximum allowable flow depth of the first-phase diversion channel 21.

[0083] Specifically, during testing, the first-phase diversion channel 21 can be designed with a water passage depth ≤ 0.6m and a water passage width ≤ 10m at the crest of the first cofferdam to ensure safe operation. The maximum unit width flow rate (including flow velocity and flow depth) of the cofferdam crest section and the spillway section will be tested separately. The smaller of the two values ​​will be taken, and a safety factor will be considered to determine the allowable unit width flow rate of the first cofferdam. After testing, the first-phase diversion channel 21 will enter normal diversion operation under the strict control of the first cofferdam.

[0084] By setting the carrying capacity of the weakest section as the upper limit of the entire channel flow, structural collapse caused by a section of the channel exceeding its allowable diversion range is avoided, which helps to ensure the overall stability of the landslide dam 11.

[0085] In one embodiment, the first water-passing cofferdam 31 includes a first sub-cofferdam body that is widened and heightened by layered masonry. Adjusting the height of the first water-passing cofferdam 31 so that the flow velocity in the first-phase diversion channel 21 is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth includes: as the water level of the landslide dammed lake 10 rises, the first sub-cofferdam body that is widened and heightened by layered masonry is constructed on the top of the first water-passing cofferdam 31 to increase the height of the first water-passing cofferdam 31.

[0086] The lifting speed of the first water-passing cofferdam 31 is dynamically balanced with the water level rise speed. By controlling the water-blocking height of the first water-passing cofferdam 31, the water-passing width and water-passing depth of the first-phase diversion channel 21 are indirectly regulated to ensure that both are always below the maximum allowable value determined by the test, so as not to waste the flood discharge space and to ensure the structural safety of the first-phase diversion channel 21.

[0087] In one embodiment, the second diversion cofferdam 32 includes a second sub-cofferdam body that is widened and heightened by layered construction. Adjusting the height of the second diversion cofferdam 32 so that the flow velocity and flow depth within the second-phase diversion channel 22 are less than the maximum permissible flow velocity and the flow depth is less than the maximum permissible flow depth includes: as the water level of the landslide dammed lake 10 rises, constructing a second sub-cofferdam body that is widened and heightened by layered construction on top of the second diversion cofferdam 32 to increase the height of the second diversion cofferdam 32.

[0088] The lifting speed of the second cofferdam 32 is dynamically balanced with the water level rise speed. By controlling the water-blocking height of the second cofferdam 32, the water-passing width and water-passing depth of the second-phase diversion channel 22 are indirectly regulated to ensure that both are always below the maximum allowable value determined by the test. This ensures that the flood discharge space is not wasted and the structural safety of the second-phase diversion channel 22 is guaranteed.

[0089] In one embodiment, the first water-passing cofferdam 31 and the second water-passing cofferdam 32 can be constructed using square precast concrete. For example, each of the first and second sub-cofferdams is a regular hexahedral structure formed by concrete pouring. Each of the first and second sub-cofferdams is equipped with lifting straps to facilitate rapid transport and masonry operations via hoisting equipment.

[0090] During the preparation of the first and second sub-weirs, the sand and gravel collected during the hydraulic excavation of the dam body 11 can be directly used to complete the concrete mixing and pouring process on-site. The construction of the first and second cofferdams 31 and 32 is carried out in a zoned and layered manner according to the actual needs of flow control, ensuring the stability of the cofferdam structure and adaptability to flow regulation requirements.

[0091] In one embodiment, such as Figure 4 As shown, the first water-passing cofferdam 31 and the second water-passing cofferdam 32 include an upstream face facing the side of the landslide dammed lake 10 and a downstream slope located on the upstream face away from the landslide dammed lake 10. The upstream face is vertically arranged, and the downstream slope is inclined. From top to bottom, the cross-sectional area of ​​the first water-passing cofferdam 31 and the second water-passing cofferdam 32 gradually increases.

[0092] The cross-section of the first water-passing cofferdam 31 and the second water-passing cofferdam 32 refers to the cross-section obtained by cutting the first water-passing cofferdam 31 and the second water-passing cofferdam 32 in the direction from the landslide dam lake 10 to the downstream river channel 60.

[0093] The vertical water-facing surface can directly block the water of the landslide dam 10, while the inclined downstream slope can help guide the water flow. The cross-sections of the first and second water-passing cofferdams 31 and 32 gradually increase from top to bottom, forming a stable shape that is wider at the bottom and narrower at the top. This can significantly lower the center of gravity of the cofferdam, improve its resistance to overturning and sliding, and effectively resist the horizontal thrust and water flow impact load of the landslide dam 10.

[0094] After the water level of landslide dam 10 stops rising, the excavation of the second-phase diversion channel 22 shall be stopped. After landslide dam 10 enters the dry season and the water level of landslide dam 10 drops, the first water-passing cofferdam 31 and the second water-passing cofferdam 32 can be removed layer by layer until the water level of landslide dam 10 drops below the bottom surface of the inlet section 231.

[0095] Depending on the needs of the comprehensive watershed planning, the landslide dam 11 can be demolished and the original river channel restored, or the landslide dam 11 can be built into a permanent dam that can be used for a long time.

[0096] It should be noted that the technical solutions or features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An emergency safety management method for high-risk landslide dammed lakes applicable to harsh environments, characterized in that, The emergency safety response methods include: When a high-risk landslide dammed lake occurs, the water body of the landslide dammed lake is obtained and the water body is used to treat the slope and seepage of the landslide dam. Before the water level of the landslide dammed lake reaches the pass of the landslide dam, a first-stage diversion channel is excavated at the pass, and a first water-passing cofferdam is set at the end of the first-stage diversion channel facing the landslide dammed lake; one end of the first-stage diversion channel is connected to the landslide dammed lake, and the other end is connected to the downstream river channel; When the water level of the landslide dammed lake rises until the water enters the first-phase diversion channel, the height of the first water-passing cofferdam is adjusted so that the flow velocity in the first-phase diversion channel is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth. During the period when the water of the landslide dammed lake is diverted through the first-stage diversion channel, a plurality of second-stage diversion channels are excavated sequentially on at least one side of the first-stage diversion channel, and a second water-passing cofferdam is set at the end of each second-stage diversion channel facing the landslide dammed lake; each second-stage diversion channel is immediately used to divert the water of the landslide dammed lake after its construction is completed, so as to increase the total diversion flow of the water of the landslide dammed lake; One end of the second-phase diversion channel is connected to the landslide dammed lake, and the other end is connected to the downstream river channel; the bottom height of the second-phase diversion channel is greater than that of the first-phase diversion channel; from the first-phase diversion channel to the second-phase diversion channel, the bottom heights of the plurality of second-phase diversion channels increase sequentially; for each second-phase diversion channel, when the water level of the landslide dammed lake rises until the water enters the second-phase diversion channel, the height of the second water-passing cofferdam is adjusted so that the flow velocity in the second-phase diversion channel is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth, and at the same time, the height of the first water-passing cofferdam is adjusted so that the flow velocity in the first-phase diversion channel is less than the maximum allowable flow velocity and the flow depth is less than the maximum allowable flow depth; The water in the landslide dammed lake is guided to the downstream river channel using the first-phase diversion channel and the second-phase diversion channel.

2. The emergency safety response method according to claim 1, characterized in that, During the period when the water of the landslide dammed lake is diverted through the first-stage diversion channel, a plurality of second-stage diversion channels are excavated sequentially on at least one side of the first-stage diversion channel, including: Excavate a second-phase diversion channel adjacent to the first-phase diversion channel; for each second-phase diversion channel located on the same side as the first-phase diversion channel, while the second-phase diversion channel closer to the first-phase diversion channel is used to divert the water of the landslide dammed lake, excavate an adjacent second-phase diversion channel on the side of the second-phase diversion channel closer to the first-phase diversion channel that is away from the first-phase diversion channel.

3. The emergency safety response method according to claim 1, characterized in that, After setting up the first water-passing cofferdam at the end of the first-phase diversion channel facing the landslide dammed lake, the emergency response method further includes: The water in the landslide dammed lake was guided into the first-phase diversion channel for testing, and the maximum allowable flow velocity and maximum allowable flow depth of the first-phase diversion channel were measured. After testing the first phase of the diversion channel, the water from the landslide dammed lake was diverted into the first phase of the diversion channel for discharge.

4. The emergency safety handling method according to claim 3, characterized in that, The first-phase diversion channel includes an inlet section, a weir crest section, and a spillway section connected in sequence; the inlet section is connected to the landslide dammed lake, and the spillway section is connected to the downstream river channel; the first water-passing cofferdam is set in the inlet section; The measurements obtained for the maximum permissible flow velocity and maximum permissible flow depth of the first-phase diversion channel include: The maximum allowable flow velocity and the maximum allowable flow depth of the weir crest section and the spillway section are measured respectively; the smaller of the maximum allowable flow velocity of the weir crest section and the spillway section is taken as the maximum allowable flow velocity of the first-phase diversion channel; the smaller of the maximum allowable flow depth of the weir crest section and the spillway section is taken as the maximum allowable flow depth of the first-phase diversion channel.

5. The emergency safety handling method according to claim 1, characterized in that, The first-phase diversion channel and the second-phase diversion channel include an inlet section, a weir crest section, and a spillway section connected in sequence; the inlet section is connected to the landslide dammed lake, and the spillway section is connected to the downstream river channel; the bottom surface of the inlet section is horizontal, and the bottom surfaces of the weir crest section and the spillway section are inclined, and the bottom slope of the spillway section is greater than or equal to the bottom slope of the weir crest section; The inlet section is used to guide the water of the landslide dammed lake into the crest channel section, and the spillway section is used to guide the water flow of the crest channel section to the downstream river channel.

6. The emergency safety handling method according to claim 5, characterized in that, The bottom surfaces of the inlet section, weir crest section, and spillway section are all equipped with bottom protection, and the slopes of the inlet section, weir crest section, and spillway section are all equipped with slope protection or retaining walls.

7. The emergency safety handling method according to claim 5, characterized in that, The first water-passing cofferdam is set at the inlet section of the first-phase diversion channel, and the second water-passing cofferdam is set at the inlet section of the second-phase diversion channel; Before the water level of the landslide dammed lake rises until the water enters the first-phase diversion channel, the emergency safety handling method further includes: setting a first stilling sill at the connection between the inlet section of the first-phase diversion channel and the crest section of the first-phase diversion channel; Before the second-phase diversion channel is used to divert the water from the landslide dammed lake, the emergency safety handling method further includes: setting a second stilling sill at the connection between the inlet section of the second-phase diversion channel and the crest section of the second-phase diversion channel.

8. The emergency safety handling method according to claim 5, characterized in that, Before the water level of the landslide dammed lake rises until the water enters the first-phase diversion channel, the emergency safety handling method further includes: setting a first toothed wall at the connection between the inlet section of the first-phase diversion channel and the downstream river channel; Before the second-phase diversion channel is used to divert the water from the landslide dammed lake, the emergency safety treatment method further includes: setting a second toothed wall at the connection between the spillway section of the second-phase diversion channel and the downstream river channel.

9. The emergency safety handling method according to claim 1, characterized in that, The first water-passing cofferdam includes a first sub-cofferdam body that is widened and heightened by layered masonry, and the second water-passing cofferdam includes a second sub-cofferdam body that is widened and heightened by layered masonry; Adjusting the height of the first water-passing cofferdam to make the flow velocity in the first phase diversion channel less than the maximum allowable flow velocity and the flow depth less than the maximum allowable flow depth includes: as the water level of the landslide dam lake rises, constructing a wider and higher first sub-weir body in layers on the top of the first water-passing cofferdam to increase the height of the first water-passing cofferdam. Adjusting the height of the second water-passing cofferdam to make the flow velocity in the second-phase diversion channel less than the maximum allowable flow velocity and the flow depth less than the maximum allowable flow depth includes: as the water level of the landslide dam lake rises, constructing a wider and higher second sub-cofferdam in layers on top of the second water-passing cofferdam to increase the height of the second water-passing cofferdam.

10. The emergency safety handling method according to claim 1, characterized in that, The emergency safety response methods also include: After the water level of the landslide dammed lake stops rising, the excavation of the second-phase diversion channel shall be stopped; after the landslide dammed lake enters the dry season and the water level of the landslide dammed lake drops, the first and second water-passing cofferdams shall be dismantled layer by layer. The landslide dam can be dismantled and the river channel restored, or the landslide dam can be converted into a long-term usable dam.

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