Bank slope supporting treatment method under limited condition

Abstract

The invention discloses a bank slope supporting treatment method under limited conditions. The method comprises the steps that S1, a temporary pump station is built; s2, a temporary water diversion channel, a temporary water catchment forebay and a permanent and temporary combined water outlet pool are built, a water inlet of the temporary water diversion channel is close to the old water diversion channel, an outlet of the temporary water diversion channel is communicated with the temporary water catchment forebay, and the temporary water catchment forebay is communicated with an outlet of the permanent and temporary combined water outlet pool through a pump set; s3, after the procedures of S1 and S2 are completed, the old water diversion channel is cut off, the temporary water diversion channel and the old water diversion channel are opened, and a temporary pump station is started; s4, the old pump station is dismantled, meanwhile, a new pump station is built, and a water outlet of the new pump station communicates with the permanent and temporary combined water outlet pool; s5, after the step S4 is completed and the closure part of the old diversion canal is opened, the opening of the temporary diversion canal is cut off, and meanwhile, a new pump station is started; s6, in any working procedure from S1 to S5, the old water diversion channel is subjected to segmented dredging, and meanwhile, the shoreline of the old water diversion channel is subjected to supporting treatment; and S7, the temporary pump station is dismantled, and the auxiliary project of the area occupied by the temporary pump station is

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bank slope support and treatment, in particular to a bank slope support and treatment method under restricted conditions. BACKGROUND

[0002] In order to improve the safety of irrigation projects, the utilization level of water resources, and the agricultural production conditions, the local government has carried out irrigation area extension and water saving reconstruction projects, for example, the extension and modernization reconstruction project of the Simashan Irrigation Area in Anhui Province, which covers the irrigation areas of Quanjiao, Lai'an, He County, Henshan and Feidong counties in the south of the Jianghuai watershed. The designed and reconstructed irrigation area is 1.3 million mu. The Simashan Irrigation Area extension and modernization reconstruction project implemented in Quanjiao County of Chuzhou City in Anhui Province is located within the boundaries of Quanjiao County in Anhui Province. The main construction contents are as follows: the first Suoyao Station is demolished and rebuilt, the second Suoyao Station is expanded, the Xiaolu water diversion sluice is newly built, the length of the channel dredging is 20.01 km, the length of the channel protection is 20.01 km, the length of the newly built channel dike wave wall is 7.53 km, and 102 channel system structures are treated. Among them, part of the backbone project and irrigation piece has the problem of insufficient irrigation water source project. The existing water source project is aging and in disrepair. The water conveying channel is seriously silted, leaked and diseased. The channel dike lacks protection measures. The channel system structure is aging. The measuring water facilities are insufficient. The management means and management facilities are backward, etc. Therefore, there is an urgent need for a bank slope support and treatment method under restricted conditions to solve the above problems. SUMMARY

[0003] The purpose of the present application is to provide a bank slope support and treatment method under restricted conditions to solve the above problems.

[0004] In order to achieve the above purpose, the present application adopts the following technical scheme: a bank slope support and treatment method under restricted conditions, comprising: S1, constructing a temporary pump station; the temporary pump station comprises a pump station equipment installation plant and a pump station joint control equipment plant, a pump group is installed in the pump station equipment installation plant, and joint control equipment is arranged in the pump station joint control equipment plant; S2, constructing a temporary water diversion channel, a temporary water collection forebay and a permanent and temporary combined water outlet pool, the temporary water diversion channel inlet is close to the old water diversion channel, the temporary water diversion channel outlet is communicated with the temporary water collection forebay, and the temporary water collection forebay and the permanent and temporary combined water outlet pool are communicated through the pump group; S3, after the completion of S1 and S2, the old water diversion channel is blocked near the temporary water diversion channel inlet, the temporary water diversion channel and the old water diversion channel are connected, the temporary pump station is started, and the water flow is guided from the temporary water collection forebay to the permanent and temporary combined water outlet pool through the pump group; S4, removing the old pump station, and simultaneously constructing a new pump station, the new pump station outlet is communicated with the permanent and temporary combined water outlet pool; S5. After completing the S4 process, open up the interception section of the old water diversion channel, cut off the temporary water diversion channel outlet, and start the new pumping station at the same time. S6. In any of the procedures from S1 to S5, the old water diversion channel is dredged in sections, and the shoreline of the old water diversion channel is supported and treated. S7. Dismantle the temporary pumping station and restore the ancillary works in the area occupied by the temporary pumping station.

[0005] Preferably, the pump set is a small pump set with multiple sets arranged in a coordinated manner.

[0006] Preferably, the depth of the temporary catchment pool is greater than the depth of the temporary water diversion channel.

[0007] Preferably, the temporary catchment pool is a depression or a converted pond. The silt at the bottom of the temporary catchment pool is filled into geotextile bags. After the silt at the bottom of the temporary catchment pool has solidified, it is used to repair the shoreline of the temporary catchment pool. Environmentally friendly flocculants are added simultaneously during the filling process.

[0008] Preferably, the main frame of the temporary pumping station is composed of multiple steel pipe columns, the walls of the temporary pumping station are composed of a combination of light steel keel and sandwich panels, and the top of the temporary pumping station is covered with waterproof steel tiles.

[0009] Preferably, the permanent and temporary combined outlet pool support consists of vertically arranged reinforced concrete sheet piles and retaining walls.

[0010] Preferably, when the shoreline of the old water diversion channel is a silty and soft foundation section, precast pile groups are driven in using the pile driving method. After the original soil on the top of the precast pile groups is removed, cement-soil is used for replacement, and then a concrete retaining wall is poured.

[0011] Preferably, when the shoreline of the old water diversion channel is a section of slope collapse, precast sheet piles are arranged in rows along both sides of the old water diversion channel, and adjacent precast sheet piles are joined by male and female tenons, and core-filling concrete is poured into the core of the sheet piles.

[0012] Preferably, when the old water diversion channel shoreline is a landslide-prone section, the landslide body and the soil 0.5m below the landslide layer of the old water diversion channel shoreline are excavated, and a stepped ecological frame is set up based on the slope surface to reinforce the slope of the old water diversion channel shoreline. Drainage blind pipes are pre-installed at the bottom of the slope surface step by step, and then the soil of the old water diversion channel shoreline is backfilled and shaped.

[0013] Preferably, when the shoreline of the old water diversion channel is a wetland shoal, prefabricated imitation wood piles are driven into the seabed in close rows using a floating piling machine to form a support belt for the old water diversion channel shoreline. Geotextile bags are then laid on top of the prefabricated imitation wood piles, and silt dredged from the old water diversion channel is blown into the geotextile bags. After the silt inside the geotextile bags has solidified, the solidified silt is used to shape the wetland shoal topography and repair the damaged wetland shoal shoreline.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. The construction of temporary pumping stations, temporary water diversion channels, and temporary catchment pools can solve the problem of water diversion for slope support and treatment, and meet the needs of water pumping for irrigation, drought relief and flood drainage during construction. This solves the contradiction between water demand that arises during the construction deployment of old pumping station demolition and new pumping station construction.

[0015] 2. A shoreline support and management plan was developed according to local conditions. Based on the different topography of the old water diversion channel shoreline, targeted management methods were given to complete the support and management quickly and efficiently. At the same time, the channel bank slope disease was eliminated, and the damage to nearby roads, houses, farmland and other areas was prevented from expanding. The goal of protecting the surrounding ecological environment and water quality from secondary pollution was achieved.

[0016] 3. By rationally arranging each process, we can solve problems such as construction diversion, site constraints, complex geology, difficulty in land acquisition and relocation, schedule constraints, earthwork balance, multiple types of shoreline management, and large workload. At the same time, we can solve the contradictions between the surrounding environment and water demand faced by the construction deployment of the demolition of the old pumping station and the construction of the new pumping station, and avoid the occurrence of problems such as encroachment on farmland, forest land, and existing drainage ditches. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the construction process for a slope support and treatment method under constrained conditions. Figure 2 This is a cross-sectional view of the landslide section treatment in Example 1; Figure 3 This is a schematic diagram of the landslide section treatment plan in Example 1; Figure 4 This is a cross-sectional view of the landslide section treatment in Example 2; Figure 5 This is a cross-sectional view of the landslide section treatment in Example 3. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] Please see the appendix Figure 1 A method for slope protection and management under constrained conditions, comprising: S1. Construct a temporary pumping station; The temporary pumping station includes a pumping station equipment installation workshop and a pumping station control equipment workshop. Pump sets are installed in the pumping station equipment installation workshop, and control equipment is installed in the pumping station control equipment workshop. S2. Construct a temporary water diversion channel, a temporary forecourt, and a combined permanent and temporary outlet pool. The inlet of the temporary water diversion channel is close to the old water diversion channel, and the outlet of the temporary water diversion channel is connected to the temporary forecourt. The outlet of the temporary forecourt and the combined permanent and temporary outlet pool are connected by a pump set. S3. After the completion of S1 and S2, the old water diversion channel is intercepted at the entrance of the temporary water diversion channel, the temporary water diversion channel and the old water diversion channel are opened up, the temporary pumping station is activated, and the water flow is diverted from the temporary collection pool to the permanent-temporary combined outlet pool through the pump set. S4. Demolish the old pumping station and build a new pumping station at the same time. The outlet of the new pumping station is connected to the permanent and temporary combined outlet pool. S5. After completing the S4 process, open up the interception section of the old water diversion channel, cut off the temporary water diversion channel outlet, and start the new pumping station at the same time. S6. In any of the procedures from S1 to S5, the old water diversion channel is dredged in sections, and the shoreline of the old water diversion channel is supported and treated. S7. Dismantle the temporary pumping station and restore the ancillary works in the area occupied by the temporary pumping station; The purpose of constructing temporary pumping stations is to divert and intercept water flow and to combat drought and floods. These temporary pumping stations will replace the functions of the old pumping stations that are to be demolished. When farmland and ponds at the foot of the hills are in flood season, the temporary pumping stations will enter flood control and drainage mode. The pumped floodwaters will be discharged into the flood discharge channel at the waist of the hills and into the water system such as wetland flood storage areas. It should be noted that the construction time of the temporary pumping station should be selected during the "window period" when no pumping station is on duty. The site should also be selected nearby. Moreover, the comprehensive indicators of the temporary pumping station must meet the requirements of diverting water for irrigation, drought relief and water replenishment, and flood drainage during the flood season. The temporary catchment pool does not require additional site acquisition. A pond or depression can be temporarily selected on the construction site to reduce the amount of earthwork excavation for the temporary catchment pool and the subsequent reclamation work, thereby reducing the cost of land acquisition and reclamation. The site selection of the temporary water diversion channel should adhere to the principle of minimizing earthwork excavation and utilize the old water diversion channel on-site. The on-site utilization of the old water diversion channel is divided into two sections. The first section is the connection between the front end of the old water diversion channel and the main river. Its original front inlet gate and the middle control gate of the channel are retained, and the channel alignment remains basically unchanged. Only dredging of the channel is required to improve the water flow channel and ensure smooth water diversion. The second section is the connection between the end of the old water diversion channel and the temporary water diversion channel. The end of the old water diversion channel is intercepted and the old water diversion channel and the temporary water diversion channel are opened up. The water flow is diverted to the temporary catchment pool through the temporary water diversion channel, and the water in the temporary catchment pool is diverted to the permanent and temporary combined outlet pool through a temporary pumping station. After the S1-S3 processes are completed, the preparatory work for the demolition of the old pumping station is completed. The work of the old pumping station is replaced by a temporary pumping station. Then the old pumping station is demolished and a new pumping station is built on the original site. After the new pumping station is built, the old water diversion channel is reconnected to the new pumping station. After the temporary water diversion channel is cut off, the temporary pumping station is demolished and the ancillary works in the area are restored. It is important to note that the old water diversion channel will continue to serve its function of diverting water after the new pumping station is put into use. Therefore, dredging and support maintenance of the old water diversion channel is an essential procedure. In order to resolve the conflict between the surrounding environment and water demand during the demolition and reconstruction period, the dredging and support maintenance of the old water diversion channel needs to be carried out during the construction window period when there is no busy irrigation season or flood season. At the same time, considering the long length of the old water diversion channel (for example, the dredging length in the Quanjiao construction project is 20.01KM), the construction will be carried out in sections and in parallel and synchronous manner.

[0020] Specifically, the pump sets consist of multiple small pump sets arranged in a coordinated control configuration. Considering construction costs and the fact that temporary pump stations are only temporary replacements for new pump stations and will be dismantled later, after discussion, comparison, and market consultation, instead of purchasing large pump sets, we decided to raise funds to lease multiple small pump sets in a coordinated control configuration. This approach can meet the flow rate, head, and functional requirements without the need to construct large permanent plants or purchase and install large overhead cranes (only ordinary truck cranes are required). The cost is low, and transportation, hoisting, and dismantling are convenient. It is a reusable solution.

[0021] Specifically, the depth of the temporary catchment pool is greater than the depth of the temporary water diversion channel. During the process of the temporary water diversion channel guiding water into the temporary catchment pool, multiple single-unit centrifugal pump sets and their auxiliary pipelines need to be installed at the connection point between the temporary catchment pool and the temporary water diversion channel. Therefore, the temporary catchment pool needs to have a certain reserved depth. For example, in the Quanjiao construction project, the cross-section of the temporary water diversion channel is approximately 8m wide at the top, 5m wide at the bottom, and 5m deep, while the temporary catchment pool is approximately 25m long, 15m wide, and 7.5m deep. The 2.5m difference in depth between the temporary catchment pool and the temporary water diversion channel is the reserved installation depth. This reserved installation location requires the installation of 13 single-unit double-suction centrifugal pump sets and their auxiliary pipelines. The pump suction pipe port diameter is 300mm, and the port is installed approximately 150mm above the bottom of the temporary catchment pool. Simultaneously, other auxiliary accessories, such as float level gauges, also need to be installed at this location.

[0022] Specifically, the temporary catchment pool is a depression or pond that has been converted. The silt at the bottom of the temporary catchment pool is filled into geotextile bags. After the silt at the bottom of the temporary catchment pool has solidified, it is used to repair the shoreline of the temporary catchment pool. Environmentally friendly flocculants are added at the same time during the filling process. To reduce construction costs and shorten construction time, the temporary catchment pool was selected by temporarily requisitioning a pond. If no pond could be requisitioned, a depression could be selected for direct excavation without additional site requisition, thus reducing the amount of excavation for the temporary catchment pool and subsequent reclamation work, thereby reducing requisition and reclamation costs. At the same time, the selection of a pond or depression further reduced construction costs. For the silt at the bottom of the temporary catchment pool, it can be filled into geotextile bags. Considering the accumulation of silt in the old water diversion channel, which causes water quality deterioration, environmentally friendly flocculants can be added during the filling process of the geotextile bags to purify the sludge. For example, after on-site pre-construction testing in the Quanjiao construction project, the ratio of environmentally friendly flocculants was: 0.8% PAC + (0.1%~0.3%) PAM.

[0023] Specifically, the main frame of the temporary pumping station is constructed using multiple steel pipe columns, the walls of the temporary pumping station are constructed using a combination of light steel keel and sandwich panels, and the top of the temporary pumping station is covered with waterproof steel tiles. The temporary pumping station is a workshop for installing and arranging diversion pump sets. It is approximately 20m long and 6m wide, with a net height of 4.0m. The workshop floor is a 20cm thick C30 plain concrete hardened foundation with a moisture-proof layer. The pump sets are evenly distributed on the concrete foundation inside the workshop. The workshop has 12 φ120mm Q235B steel pipe columns, with the base of the columns embedded 500mm into the ground. The upper part of the columns consists of crossbeams, side beams, and a sloping roof frame made of square steel pipes. The workshop uses light steel keel + sandwich panels as the enclosure walls, and waterproof steel tiles are laid on the sloping roof. The pump station control equipment workshop is the installation and layout workshop for the unit's online monitoring system and control system equipment; it is a light steel keel + sandwich panel + color steel tile roof building, about 20m long and 6m wide, with a net height of 3.2m. The workshop floor is a C20 plain concrete hardened foundation, 12cm thick, with a moisture-proof layer; the workshop is divided into multiple equipment rooms according to work needs; Temporary pumping stations are constructed using lightweight steel keel, sandwich panels, and color steel tiles that are easy to install. This not only reduces costs but also offers advantages such as convenient transportation, hoisting, and dismantling. Furthermore, these materials can be reused.

[0024] Specifically, the permanent and temporary combined outlet pool support consists of vertically arranged reinforced concrete sheet piles and retaining wall revetment; The vertical arrangement of reinforced concrete sheet piles reduces construction land use. The combined permanent and temporary outlet pool adopts a "permanent-temporary combination" design, initially serving as the outlet pool for a temporary pumping station, and later as the outlet pool for a new pumping station. This combined design aligns with the "four savings and one environmental protection" (energy saving, land saving, water saving, material saving, and environmental protection) green construction concept. Furthermore, the combined permanent and temporary outlet pool has a combined rectangular and trapezoidal shape. The rectangular pool measures 20m long, 16.9m wide, and 4.75m deep; the trapezoidal pool measures 20m long on one side and 16.9m wide on the other. The pool has a side length of 7m, a distance of 15m from the long side to the short side, and a depth of 3.25m. It should be noted that the permanent and temporary combined outlet pool also has an outlet channel. The connection of the channel and most of the channel use vertical support slope protection with sheet piles and concrete cap beams. A small part of the water diversion channel section uses concrete gravity retaining wall slope protection. The dimensions of the outlet channel are: length 7.5km, width 7m, initial section depth 3.25m, and subsequent standard section depth 2.3m. The outlet channel guides the water flow into the reservoir (the above data is set according to the Quanjiao construction project and can be appropriately adjusted according to the actual project).

[0025] Considering that old water diversion channels are usually quite long, different sections of the old water diversion channel shoreline have different conditions. A single method cannot be used to treat the entire old water diversion channel shoreline. It is necessary to adopt a "one-size-fits-one" approach based on local conditions and use targeted technological methods for support and treatment in different sections. To facilitate understanding, the "Quanjiao Pian Construction Project" will be used as an example for further explanation.

[0026] Specifically, when the shoreline of the old water diversion channel is a silty and soft foundation section, precast pile groups are driven in using the pile driving method. After the original soil on the top of the precast pile groups is removed, cement soil is used for replacement. After replacement, a concrete retaining wall is poured. The example scenario for the silt-soil soft soil section is located on the right bank of the diversion canal of the Suyao Level 1 Station. The silt layer is interspersed between "medium to heavy silty loam" and "heavy silty loam to silty clay", with a thickness of approximately 2m-4m. The specific engineering geological conditions are as follows: The surface layer is plain fill soil, mainly heavy silty loam, containing a small amount of boulders and construction waste. Below the surface layer are medium to heavy silty loam, silty medium to heavy silty loam, heavy silty loam to silty clay, and heavy silty loam to silty clay. The specific construction methods for the above-mentioned silt-rich soft soil section are as follows: The support structure consists of precast pile groups, cement-soil replacement, and retaining walls. The silt at the bottom of the retaining wall is about 4.0m deep (thickness). The precast concrete piles are driven by excavators equipped with hydraulic vibratory hammer pile drivers using the vibratory pile driving method. Truck cranes and flatbed trucks are also used for transporting the piles. The precast concrete piles are 150mm in diameter and 4.5m in length, with C30 concrete grade. The longitudinal spacing between adjacent precast piles is 700mm, and the transverse spacing is 600mm, 700mm, and 850mm, with a total of 4 rows of precast piles arranged transversely. The tip of the precast concrete piles has been improved. The original tip length was about 300mm and the tip angle was about 45°. The improved tip length is 380mm and the tip angle is about 35°. The tip-sharpening treatment significantly improves the penetration performance of the precast piles. The tip design reduces the contact area at the pile tip and reduces the penetration resistance. According to the principles of mechanics, the pointed shape can effectively transfer concentrated stress to the soil layer, making it easier for the pile to penetrate the soil layer. The improved penetration efficiency can be increased by about 25%. The pointed treatment also optimizes the pile-soil interaction. The pointed shape helps to compact the surrounding soil and increase the frictional resistance around the pile. At the same time, the pointed design reduces soil disturbance during the pile driving process, which helps to maintain the integrity of the soil structure. The stress characteristics of the pile end directly affect the bearing capacity of the pile. The pointed design makes the stress distribution more reasonable and reduces the possibility of pile end failure. At the same penetration depth, the end resistance of the pointed wooden pile is reduced by about 40% compared with the flat-headed wooden pile, which is conducive to the pile body being better embedded in the bearing layer. After the precast concrete piles are completed, cement-soil replacement construction is carried out on the pile top. That is, after the original soil on the pile top is removed, cement-soil is replaced and compacted in layers to ensure the stability of the retaining wall foundation. Specifically, 10% cement-soil is used for replacement in the pile top area, the replacement depth is 600mm, and the compaction degree is not less than 0.96. After the above procedures are completed, the concrete retaining wall is poured. The concrete retaining wall is a reinforced concrete gravity structure with a base slab at the bottom and the wall body above the base slab. The wall body is equipped with reverse filter drainage pipes. The base slab is poured first, followed by the wall body, in two stages. The wall body is poured in sections along the channel direction (each section is about 10m long and the retaining wall is poured at intervals, with the intervals serving as the locations for subsequent filler pours). After the first set of filler pours is completed, the empty sections between the completed retaining walls are poured in the second set. During this period, it is also necessary to strengthen the concrete vibration and daily curing to improve the construction quality.

[0027] Specifically, when the shoreline of the old water diversion channel is a section of slope collapse, precast sheet piles are arranged in rows along both sides of the old water diversion channel. Adjacent precast sheet piles are joined by male and female tenons, and core-filling concrete is poured into the core of the sheet pile. The example of the slope collapse is located at the outlet of the Suyao Level 1 Station and the connection section of the main canal revetment. The silt layer is mixed between medium to heavy silty loam and heavy silty loam to silty clay, with a thickness ranging from approximately 2.3m to 5m. It also contains a layer of soil with weak expansion potential. The specific engineering geological conditions are as follows: The surface layer is a plain fill layer, mainly composed of heavy silty loam, containing a small amount of boulders and construction waste, with high compressibility. Below the surface layer are medium to heavy silty loam, silty medium to heavy silty loam, heavy silty loam to silty clay, heavy silty loam to silty clay, light to medium silty loam and gravelly fine sand. The specific construction methods for the aforementioned slope collapse section are as follows: Precast sheet piles are arranged in rows along both sides of the channel or pump station outlet pool. Excavators equipped with hydraulic vibratory hammers are used for pile driving using the vibratory pile driving method. Adjacent precast sheet piles are interlocked using male and female tenons to form a precast sheet pile retaining wall. The pile dimensions are 320×600mm, with an inner hole of φ180mm. C80 concrete is used for precasting, with an average length of 5m and a embedment depth of 3m. A C25 concrete cap beam (crown beam) is installed at the top of the sheet pile, with the top elevation at the design water level +0.3. The vertical main reinforcement in the pile core consists of 6 φ12mm bars, each 1260mm long, and 5 φ10@200 stirrups. Reinforcement connections are made by welding, with a single-sided weld lap length of not less than 10d and a double-sided weld lap length of not less than 5d, where d is the larger diameter of the longitudinal reinforcing steel. Welded joints should be staggered, and the percentage of reinforcement joint area in the connection section (within 35d) should not exceed a certain percentage. The sheet pile top is embedded 100mm into the cap beam, and the steel reinforcement in the pile core is staggered into the cap beam (crown beam) by no less than 250mm. The strength grade of the sheet pile core filling concrete is the same as that of the cap beam and should not be lower than C25. The size of the cap beam is 520mm×300mm. The main reinforcement is 6φ16, 3φ10@400, and 4φ12, arranged along the entire length. The stirrups are φ10@200. The length of the male tenon of the precast sheet pile is increased to 2m, and the size of its male tenon tip is controlled at the tenon width ≈ 0.85 times the female tenon width. The above-mentioned size improvement is conducive to the quick and accurate insertion of the female tenon, and also conducive to the tight interlocking of the male tenon and the female tenon, so that the adjacent piles are firmly connected and the overall support of the soil behind the pile is more effective. The tenons between the precast sheet piles in the seepage section are filled with asphalt mortar. Expansion joints are set every 25m in the cap beam (crown beam). After filling the joints with high-strength polyethylene closed-cell foam board, asphalt mortar is used. After the above procedures are completed, the core-filling concrete is poured into the precast sheet pile core. It is important to note that before pouring the core-filling concrete, the clean slurry layer on the inner wall of the precast sheet pile should be cleaned. According to the design requirements, measures such as applying a concrete interface agent to the inner wall or using expansive concrete for core filling can be adopted to improve the integrity of the core-filling concrete and the wall pile body concrete. Meanwhile, considering the special characteristics of the slope collapse section, the top of the precast sheet piles was optimized by adopting an inverted "U"-shaped cap beam. The top of the sheet pile is embedded 100mm into the cap beam, and the steel bars in the pile core are staggered into the cap beam (crown beam) by no less than 250mm. The strength grade of the sheet pile core filling concrete should not be lower than C25. The cap beam size is 520mm×300mm, the main reinforcement is 6φ16, 3φ10@400, and 4φ12, arranged along the entire length, and the stirrups are φ10@200. The cap beam capping and the precast pile are anchored by steel bars and "U"-shaped inverted fastening, which are tightly and firmly combined to ensure the stability of the upper slope protection and soil and eliminate the risk of lateral slippage.

[0028] Specifically, when the old water diversion channel shoreline is a landslide-prone section, the landslide body and the soil 0.5m below the landslide layer of the old water diversion channel shoreline are excavated. A stepped ecological frame is set up based on the slope surface to reinforce the slope of the old water diversion channel shoreline. Drainage blind pipes are pre-installed at the bottom of the slope surface step by step. Then the soil of the old water diversion channel shoreline is backfilled and shaped. The landslide-affected section is the Xiafeng Hydropower Station section of the Suyao Level 1 Station. The soil of the slope and landslide body in the affected section is relatively loose, with numerous surface cracks. From the top of the slope to the upper edge of the concrete revetment, the landslide soil in the Xiafeng Hydropower Station section is obviously loose and dark in color. Supplementary geological surveys show that the landslide soil in this section is mainly filled with excavated soil from the canal cutting and ridge excavation, mainly heavy silty loam, with heavy silty loam to silty clay underneath. The left bank of the Zhangwuguan South Gate section is heavy silty loam to silty clay, showing weak expansion potential; the right bank is medium to heavy silty loam, and the lower part of the above terrain is heavy silty loam to silty clay. According to on-site geological mapping and investigation, the landslide is a small, shallow landslide. The soil layers of the landslide body and the sliding bed are mainly heavy silty loam and silty clay. The exposed soil layer of the landslide body is 0.50~2.65m thick. The landslide occurred on the contact zone between heavy silty loam and silty clay. The soil layers at the site are mainly weakly expansive, with moderate expansiveness in some areas. The atmospheric influence depth in this area is 3.2m, and the depth of the abrupt atmospheric influence layer is 1.4~1.5m. The soil has undergone repeated wet and dry cycles, resulting in the development of expansion and contraction cracks and damage to its integrity. The surface layer is often divided into a loose structure by expansion cracks, and the C and Φ values ​​are greatly reduced. In addition, the shallow soil has developed pores and worm holes, often containing perched water from the upper layer, which easily leads to shallow expansion and contraction deformation and damage. Meanwhile, the top of the channel slope and the surface soil of the fill contain a lot of perched water. Due to construction reasons, the water level in the channel is low and a large amount of precipitation enters the soil, causing the soil to undergo strong alternating wet and dry changes in a short period of time, which greatly reduces the mechanical strength. At the same time, the local grayish-white secondary clay becomes soft plastic after being saturated with water, forming a weak and slippery surface. The soil is saturated with water, its own weight increases, the sliding force increases, the groundwater level rises, and pore water pressure is generated on the slope, which enhances the landslide sliding ability. Furthermore, the landslides all occurred in the ridge section, with a cutting depth of about 8 to 10 meters. The slope ratio of the channel side is generally steeper than 1:2.0, and the slope height is relatively large. The steep slope ratio can also cause slope instability. The ponds and ditches behind the bank provide a water source for groundwater activity, which is not conducive to the stability of the bank slope. The specific handling methods for the above situation are as follows: Referring to the supplementary geological survey report, the boundaries between the landslide body and the sliding bed were first clarified. According to the original design requirements, the landslide body and the soil 0.5m below the sliding layer were excavated, and the slope was re-filled in layers according to the design. Termite extermination was carried out simultaneously in areas where termites were present. After the termite nests along the entire dike were excavated and backfilled, grouting with medicated filling (mixed with 10% imidacloprid suspension) was carried out at the backwater side of the dike shoulder. Considering the relatively small average thickness of the landslide, an ecological frame is set up above the first platform above the channel bottom as a slope soil reinforcement measure to increase the comprehensive shear resistance index of the slope soil. The ecological frame size is proposed to be 1.0m×1.0m×0.5m (length×width×depth). The backfill soil inside the frame is compacted, and the top is covered with turf to achieve the effect of soil consolidation. Concrete longitudinal and transverse drainage ditches are set up on the slope. At the bottom of each slope level, an internal layer of drainage blind pipes is set up with a transverse spacing of 5.0m and a transverse depth of not less than 5.0m. A longitudinal drainage blind pipe is set at the top of each transverse pipe. From the first-level platform of the water diversion channel to the toe of the channel embankment, the reinforcement is carried out in sequence using riprap toe protection, concrete toe reinforcement, and concrete lining slope protection. The specific method is as follows: After shaping the slope soil, riprap is first dumped at the lower part of the embankment toe to squeeze out silt, with a thickness of about 600mm, to stabilize the embankment toe. Then, a 100mm thick plain concrete cushion layer is poured on top of the riprap layer. A 300mm wide and 500mm high concrete retaining wall is poured on top of the cushion layer to reinforce the toe. The slope protection between the rear of the retaining wall and the first-level platform is carried out in the form of concrete lining, with a thickness of 100mm. Since the lining surface is the water-facing side at normal water level, a layer of geotextile is laid on the soil before lining. A layer of crushed stone filter layer with a thickness of at least 100mm is then laid on top of the geotextile. After that, the lining concrete is poured to complete the slope protection steps.

[0029] It is important to note that seepage prevention treatment should be carried out in areas of severely leaking localized dikes. This involves installing multi-head, small-diameter, deep-mixing pile seepage prevention walls on the water-facing side of the dike. Four-axis small-diameter cement mixing piles with a diameter of 350mm, an axis spacing of 250mm, and a linear arrangement are used for reinforcement and seepage prevention. The construction depth is 7.7m, with an effective overlap of 100mm. The dredging and mixing speed should be controlled within 1.0m / min, the cement content should be 15%, the water-cement ratio should be 1.5, the grout delivery rate should be controlled at no less than 147L / m, and the grouting pressure should be no less than 0.5MPa. A multi-head grouting method with four layers of blades, four mixing and two spraying techniques should be used to meet the requirements of the drawings and construction specifications. To ensure the uniformity of the bottom pile formation, when drilling to the design elevation, the bottom mixing and spraying should last at least 30 seconds before lifting. During the lifting process, the speed should be slowed down and controlled below 0.8m / min.

[0030] Specifically, when the shoreline of the old water diversion channel is a wetland shoal, prefabricated imitation wood piles are driven into the bottom of the water in close rows using a floating pile driver to form a support belt for the shoreline of the old water diversion channel. Geotextile bags are then laid on top of the prefabricated imitation wood piles, and silt dredged from the old water diversion channel is blown into the geotextile bags. After the silt inside the geotextile bags has solidified, the solidified silt is used to shape the wetland shoal topography and repair the damaged wetland shoal shoreline. Considering that some sections of the old water diversion channel connect with wetlands and shoals in the actual project, it is also necessary to repair the damaged sections of the wetland and shoal shoreline. The specific construction methods are as follows: C30 precast reinforced concrete imitation wood piles were used, and a floating pile driver was used for construction. The precast imitation wood piles were densely driven into the water to a depth of about 3m along the designed route to form a shoreline support zone. The imitation wood piles were φ150mm and 6m long. Geotextile bags were laid on top of the piles, and silt dredged from the ditch was blown into the geotextile bags. After pre-construction tests and comparisons to verify the environmental protection agent mixing ratio, the environmental protection agent was officially added. Large-scale dewatering and consolidation of the silt blown into the geotextile bags was carried out. After the dry mud inside the geotextile bags was consolidated, the geotextile bags were broken, and the consolidated dry mud inside the geotextile bags was used in situ to reshape the wetland shallow beach topography. Excavators were used to tidy up the terrain and repair the damaged wetland shallow beach shoreline.

[0031] Example 2 When the shoreline of the old water diversion channel is a landslide-prone section, considering the problem of excessive temporary land acquisition in the first embodiment, a second treatment plan was designed, as follows: A row of reinforced concrete bored piles is installed on the first-level platform at the bottom of the old water diversion channel. The piles are spaced 0.5m apart, with a diameter of 1.5m and a length of 5.5m. After the slope is leveled, drainage is implemented on the slope and within the slope, and turf is used for slope protection. Compared with the treatment plan for the landslide section in Example 1, this plan has a better reinforcement effect and a better treatment effect than the plan in Example 1. However, it has the problems of longer construction period and higher cost.

[0032] Example 3 When the old water diversion channel shoreline was identified as a landslide-prone section, a third remediation plan was designed, as follows: The existing channel revetment at the bottom of the old water diversion channel was demolished, and the slope sliding part was excavated to form a rectangular trench construction pit. Then, the rectangular trench reinforced concrete construction was carried out. The rectangular trench has a net width of 7.5m and a height of 3.0m. Finally, the soil behind the rectangular trench was backfilled. Combined with slope filling and finishing, slope and slope drainage and turf slope protection were implemented. Compared with the treatment of landslide disease sections in Examples 1 and 2, the treatment effect in Example 3 is the best. However, it also has the problems of the longest construction period and the highest cost. In actual construction, the appropriate solution can be selected according to the specific situation.

[0033] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for slope protection and management under constrained conditions, characterized in that, include: S1. Construct a temporary pumping station; The temporary pumping station includes a pumping station equipment installation workshop and a pumping station control equipment workshop. The pumping station equipment installation workshop is equipped with pump sets, and the pumping station control equipment workshop is equipped with control equipment. S2. Construct a temporary water diversion channel, a temporary forecourt, and a combined permanent and temporary outlet pool. The inlet of the temporary water diversion channel is close to the old water diversion channel, and the outlet of the temporary water diversion channel is connected to the temporary forecourt. The outlet of the temporary forecourt and the combined permanent and temporary outlet pool are connected by a pump set. S3. After the completion of S1 and S2, the old water diversion channel is intercepted at the entrance of the temporary water diversion channel, the temporary water diversion channel and the old water diversion channel are opened up, the temporary pumping station is activated, and the water flow is diverted from the temporary collection pool to the permanent-temporary combined outlet pool through the pump set. S4. Demolish the old pumping station and build a new pumping station at the same time. The outlet of the new pumping station is connected to the permanent and temporary combined outlet pool. S5. After completing the S4 process, open up the interception section of the old water diversion channel, cut off the temporary water diversion channel outlet, and start the new pumping station at the same time. S6. In any of the procedures from S1 to S5, the old water diversion channel is dredged in sections, and the shoreline of the old water diversion channel is supported and treated. S7. Dismantle the temporary pumping station and restore the ancillary works in the area occupied by the temporary pumping station.

2. A method for slope protection and management under constrained conditions according to claim 1, characterized in that: The pump set consists of multiple small pump sets arranged in a coordinated manner.

3. A method for slope protection and treatment under constrained conditions according to claim 1, characterized in that: The depth of the temporary catchment pool is greater than the depth of the temporary water diversion channel.

4. A method for slope protection and management under confined conditions according to claim 1, characterized in that: The temporary catchment pool is a depression or pond that has been converted. The silt at the bottom of the temporary catchment pool is filled into geotextile bags. After the silt at the bottom of the temporary catchment pool has solidified, it is used to repair the shoreline of the temporary catchment pool. Environmentally friendly flocculants are added at the same time during the filling process.

5. A method for slope protection and management under confined conditions according to claim 1, characterized in that: The main frame of the temporary pumping station is composed of multiple steel pipe columns, the walls of the temporary pumping station are constructed using a combination of light steel keel and sandwich panels, and the top of the temporary pumping station is covered with waterproof steel tiles.

6. A method for slope protection and management under confined conditions according to claim 1, characterized in that: The permanent and temporary combined outlet pool support consists of vertically arranged reinforced concrete sheet piles and retaining walls.

7. A method for slope protection and treatment under confined conditions according to claim 1, characterized in that: When the shoreline of the old water diversion channel is a silty and soft foundation section, precast pile groups are driven in using the pile driving method. After the original soil on the top of the precast pile groups is removed, cement soil is used for replacement. After replacement, a concrete retaining wall is poured.

8. A method for slope protection and treatment under confined conditions according to claim 7, characterized in that: When the shoreline of the old water diversion channel is a section of slope collapse, precast sheet piles are arranged in rows along both sides of the old water diversion channel. Adjacent precast sheet piles are joined by male and female tenons, and core-filling concrete is poured into the core of the sheet piles.

9. A method for slope protection and treatment under confined conditions according to claim 7, characterized in that: When the old water diversion channel shoreline is a landslide-prone section, the landslide body and the soil 0.5m below the landslide layer of the old water diversion channel shoreline are excavated. A stepped ecological frame is set up based on the slope surface to reinforce the slope of the old water diversion channel shoreline. Drainage blind pipes are pre-installed at the bottom of the slope surface step by step. Then the soil of the old water diversion channel shoreline is backfilled and shaped.

10. A method for slope protection and treatment under confined conditions according to claim 7, characterized in that: When the shoreline of the old water diversion channel is a wetland shoal, prefabricated imitation wood piles are driven into the seabed in close rows using a floating piling machine to form a support belt for the old water diversion channel shoreline. Geotextile bags are then laid on top of the prefabricated imitation wood piles, and silt dredged from the old water diversion channel is blown into the geotextile bags. After the silt inside the geotextile bags has solidified, the solidified silt is used to shape the wetland shoal topography and repair the damaged wetland shoal shoreline.

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