Port section embankment reconstruction method capable of meeting flood control and drainage and ecological restoration requirements

Abstract

The invention discloses a port section embankment reconstruction method capable of meeting flood control and drainage and ecological restoration requirements, which comprises the following steps of: 1, determining an arrangement direction of an engineering embankment line according to the current situation of a current engineering embankment; determining a section type embankment scheme according to the arrangement direction of the engineering embankment line and the surrounding environment information; 2, engineering embankment seawall design is conducted according to the section type embankment scheme, and the engineering embankment seawall design comprises seawall section structure design, soft soil embankment foundation treatment meeting the embankment slope stability requirement and culvert design; 3, according to the seawall design of the engineering embankment, the engineering construction content and the construction mode thereof are determined; the embankment safety coefficient and stability of the port service area embankment are improved, construction of the embankment is promoted to reach the standard, an engineering design standard flood control and drainage scheme is strengthened, and meanwhile the ecological restoration effect is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of embankment protection structures, and specifically relates to a method for reconstructing embankments in a port section that meets the requirements of flood control, drainage and ecological restoration. Background Art

[0002] The port section embankment refers to the embankment located around the water area of ​​the port section, which is usually made of piled or excavated materials such as earth, stone, and concrete; its function is to protect the water area from floods, and it can also resist wave erosion, fix river banks, and beautify the environment; the port section embankment project has the functions of flood control and drainage, ecological restoration, etc., and plays an important role in ensuring national security and promoting economic development.

[0003] Over time, the original construction of the embankments in the port section has presented problems such as aging facilities, which has greatly reduced the service life of the embankments. In addition, the construction of the existing port service area embankments mostly adopts a unified and standardized embankment plan. There is a lack of an optimal embankment construction plan that is designed according to the original embankment characteristics and matches the port service area embankments and meets the needs of embankment protection and ecological landscape restoration. Summary of the invention

[0004] Purpose of the invention: In order to improve the safety factor and stability of the embankment in the port service area, the present invention proposes a method for reconstructing the embankment in the port section that meets the requirements of flood control, drainage and ecological restoration, strengthens flood control and drainage and improves ecological restoration.

[0005] Technical solution: A method for rebuilding the embankment in the port section that meets the requirements of flood control, drainage and ecological restoration, including the following steps:

[0006] Step 1: Determine the layout orientation of the project embankment according to the current status of the project embankment; determine the cross-section type embankment plan according to the layout orientation of the project embankment and the surrounding environment information;

[0007] Step 2: Design the engineering embankment and seawall according to the cross-section type embankment scheme. The engineering embankment and seawall design includes: seawall cross-section structure design, soft soil embankment foundation treatment that meets the requirements of embankment slope stability, and culvert design;

[0008] Step 3: Determine the construction content and method based on the embankment and seawall design.

[0009] Furthermore, the cross-sectional structure of the seawall includes the embankment body and the inner and outer embankment slope protection surfaces;

[0010] The structural elements of the seawall cross-section structure include the elevation of the top of the seawall and the detailed structure of the seawall body;

[0011] The seawall cross-section structure design includes:

[0012] S200: Select the outer embankment slope protection type according to the cross-sectional embankment plan; determine the embankment crest elevation in the structural element of the seawall cross-sectional structure by optimizing and comparing the outer embankment slope protection type and embankment slope ratio;

[0013] S210: Determine the detailed structure of the seawall cross-section structure;

[0014] S220: Design the seawall cross-section structure using the determined crest elevation and detailed structure of the embankment.

[0015] Furthermore, the top elevation of the embankment is calculated according to the following formula:

[0016] Z P =h p +R F％ +A(1)

[0017] In the formula, Z P represents the design embankment top elevation, h p Indicates the design high tide level, R F％ It represents the wave run-up value with cumulative frequency F calculated according to the design wave, and A represents the safety heightening;

[0018] Among them, the wave height value R F％ Calculated according to the following formula:

[0019] R F％ =K Δ K v R1H 1％ K F (2)

[0020] In the formula, K Δ Indicates the rough permeability coefficient related to the type of embankment slope protection, K V It represents the empirical coefficient related to wind speed and water depth in front of the dike, H 1％ Indicates the wave height value with cumulative frequency F = 1%, K F Indicates the conversion factor of the cumulative frequency of climbing; R1 indicates when K Δ =1.0m,H 1％ = The climbing height value when 1.0m; the calculation formula of R1 is expressed as:

[0021] R1=1.24th(0.432M)+[(R1) m -1.029].R(M) (3)

[0022]

[0023]

[0024] R(M)=1.09M 3.32exp(-1.25M) (6)

[0025] Where th represents the hyperbolic tangent function, M represents the function related to the m value of the slope, (R1) m It represents the maximum value of the creepage corresponding to a certain d / L, d represents the water depth in front of the dike, L represents the wavelength, H represents the wave height, sh represents the hyperbolic sine function, R1 represents the wave creepage, which is positive upwards from the design water level; R(M) represents the creepage function;

[0026] When the seawall is designed according to the allowable overtopping, the overtopping volume at the top of the seawall shall be calculated and verified. The overtopping volume at the top of the seawall is the overtopping water volume per unit seawall width per unit time.

[0027] Under windless conditions, the overtopping water volume is calculated as follows:

[0028]

[0029] Where g represents the overtopping amount, represents the average wave height in front of the dike, T represents the effective wave period, g represents the gravitational acceleration, It indicates that the wave is steep in front of the dike, and L indicates the wavelength;

[0030] Under windy conditions, the overtopping water volume is obtained by multiplying the overtopping water volume under windless conditions by the wind correction factor K′. The wind correction factor K′ is expressed as:

[0031] K′=1.0+W f (H C / R+0.1)sinθ (8)

[0032] Where W f It represents the coefficient related to wind speed, θ represents the slope angle of the seawall facing the sea, and R represents the wave run-up value on the seawall.

[0033] Furthermore, the detailed structure of the seawall cross-section structure includes: the width of the embankment road, the embankment road surface structure, the primary platform, the primary retaining wall and the secondary retaining wall;

[0034] The detailed structure of the seawall body for determining the cross-sectional structure of the seawall specifically includes:

[0035] Determine the width of the levee crest road that meets flood control requirements;

[0036] Determine the main structure of the embankment top road surface and the cushion structure under the embankment top road surface;

[0037] Determine the elevation of the first-level platform and determine the structure of the first-level platform;

[0038] Determine the elevation and structure of the primary retaining wall;

[0039] Determine the setting elevation of the secondary retaining wall and determine the structure of the secondary retaining wall.

[0040] Furthermore, the first-level platform is used as a border defense zone, including a retaining wall and a wave-breaking wall, and the first-level platform is set at an elevation of 2.5m;

[0041] The setting elevation of the primary retaining wall is 2.50m. The primary retaining wall adopts a cast-in-place cantilever reinforced concrete structure. The upper water surface of the primary retaining wall adopts an anti-arc wave suppression structure. Concrete prefabricated blocks are used below the elevation of 1.00m of the primary retaining wall.

[0042] The setting elevation of the secondary retaining wall is 4.10m. The secondary retaining wall adopts cantilever reinforced concrete, and the wall top elevation is 4.30m. The upper water surface of the secondary retaining wall adopts an anti-arc wave suppression structure.

[0043] Furthermore, the soft soil embankment foundation treatment specifically includes the following steps:

[0044] The step of primary treatment of the silt layer at the embankment foundation by high pressure jet grouting method;

[0045] The steps of secondary treatment of the silt layer at the embankment foundation using CFG piles.

[0046] Furthermore, the step of primary treatment of the embankment foundation silt layer by high pressure jet grouting method comprises:

[0047] Determine the plane layout of the high-pressure jet grouting piles, which adopts a columnar reinforcement type with square piles;

[0048] According to the requirements of embankment slope stability, determine the length of a single high-pressure jet grouting pile;

[0049] According to the plane layout and the length of a single high-pressure jet grouting pile, cement slurry is sprayed into the silt layer of the embankment foundation with a high-pressure rotating nozzle to mix with the silt layer of the embankment foundation, thereby reinforcing the silt layer of the embankment foundation;

[0050] The steps of using CFG piles to perform secondary treatment on the silt layer at the dike foundation include:

[0051] Determine the reinforcement type of CFG piles, which adopts a columnar reinforcement type with square piles;

[0052] According to the requirements of embankment slope stability, determine the length of a single CFG pile;

[0053] The silt layer at the embankment foundation is reinforced according to the reinforcement type of CFG piles and the length of a single CFG pile.

[0054] Furthermore, the embankment slope stability requirement is determined according to the following steps:

[0055] Calculate the total stress shear strength index after high-pressure jet grouting treatment;

[0056] The embankment slope stability is calculated according to the following formula:

[0057]

[0058] Where K represents the anti-sliding stability factor of the embankment slope, W 1i , W 2i , W 2i ', W 3i 'represent the natural weight of the soil above the infiltration line of the i-th soil strip, the saturated weight of the soil between the infiltration line and the outer slope water level, the floating weight of the soil between the infiltration line and the outer slope water level, and the floating weight of the soil below the outer slope water level; b i represents the width of the i-th soil strip, α i represents the angle between the radius through the midpoint of the bottom of the i-th soil strip and the direction of gravity; C i , It represents the total stress shear strength index of the soil at the bottom of the i-th soil strip;

[0059] The anti-sliding stability safety factor of the embankment slope meets the following requirements:

[0060] Normal operating conditions: K ≥ 1.30;

[0061] Special application conditions Ⅰ: K ≥ 1.20;

[0062] Special application conditions II: K ≥ 1.10;

[0063] According to the requirements of embankment slope stability, the length of a single high-pressure jet grouting pile is determined, specifically including:

[0064] Initialize the length of a single high-pressure jet grouting pile;

[0065] Calculate the current embankment slope stability. If the current embankment slope stability meets the strict requirements, the pile length is the pile length of a single high-pressure rotary jet pile. If the current embankment slope stability does not meet the strict requirements, adjust the pile length of the single high-pressure rotary jet pile and repeat this step.

[0066] Furthermore, the total stress shear strength index after high-pressure jet grouting treatment is calculated as follows:

[0067] C=C1m f +C2(1-m f ) (9)

[0068]

[0069] Where, C is the equivalent strength index cohesion of the foundation after jet grouting pile treatment; φ is the equivalent strength index internal friction angle of the foundation after jet grouting pile treatment, m f represents the area replacement rate, C1 represents the cohesion of the pile body, C2 represents the cohesion of the soft soil layer, φ1 represents the internal friction angle of the pile body, φ2 represents the internal friction angle of the soft soil layer, K1 represents the rigidity of the jet grouting pile, and K2 represents the rigidity of the soft soil part around the pile; β represents the ratio of the settlement S1 of the pile to the settlement S2 of the soft soil part around the pile. For fill, S1<S2, β=0.5, and for rigid foundation, S1=S2, β=1;

[0070] The pile cohesion C1 is determined by the following formula:

[0071]

[0072] In the formula, f cu represents the average cubic compressive strength of the indoor reinforced test block with the same cement-soil ratio as the jet-jet pile body under standard curing conditions at 28 days of age, η represents the pile body strength reduction coefficient, It represents the internal friction angle of pile depth.

[0073] Furthermore, the culvert design specifically includes:

[0074] Calculate the vertical bearing capacity of a single CFG pile R according to the following formula: a :

[0075]

[0076] In the formula, R a represents the characteristic value of the vertical bearing capacity of a single pile, μ p represents the circumference of the pile, A p represents the cross-sectional area of ​​the pile, I represents the number of soil layers divided within the length of the pile, and q xi represents the characteristic value of the lateral resistance of the i-th layer of soil within the pile length range, l i represents the thickness of the i-th soil layer within the pile length, q p It represents the uncorrected characteristic value of the bearing capacity of the foundation soil at the pile end;

[0077] The bearing capacity of the composite foundation f is calculated according to the following formula spk :

[0078]

[0079] In the formula, f spk represents the characteristic value of composite foundation bearing capacity, m c represents the characteristic value of the bearing capacity of the composite foundation, β represents the reduction factor of the bearing capacity of the soil between piles, and f sk represents the characteristic value of soil bearing capacity between piles;

[0080] Based on the bearing capacity of composite foundation fspk , carry out culvert design.

[0081] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0082] The method of the present invention determines the layout orientation of the project embankment line by comprehensively analyzing the current status of the project embankment, determines the embankment plan according to the layout orientation of the project embankment line and the surrounding environment information, and selects the optimal embankment plan. The design of the present invention can achieve embankments and water conservancy facilities that meet the planned flood control and drainage standards, and also ensures that the project construction effectively defends against floods and storm surges in front of the embankment, so that the embankment line forms a coastal landscape belt, which not only protects the lives and property of the people on the island, but also provides people with leisure, entertainment and water-friendly space, provides a superior hardware environment for promoting the development of local tourism and investment attraction of Hengqin Island, and supports the sustainable development of regional economy and society. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 It is a flow chart of a port section embankment construction method that meets the requirements of flood control, drainage and ecological restoration of the present invention;

[0084] Figure 2 It is a general plan view of the location layout of the embankment in the port section of the present invention;

[0085] Figure 3 It is a schematic diagram of the cross-section structure of the embankment of the present invention;

[0086] Figure 4 It is a schematic diagram of the end surface structure of the embankment road retaining wall and wave-breaking wall of the present invention. DETAILED DESCRIPTION

[0087] The technical solution of the present invention is now further described in conjunction with the accompanying drawings and embodiments.

[0088] Taking the embankment of the port service area in Hengqin New Area as an example, the technical solution proposed in the present invention is applied to achieve the planned flood control and drainage standards for the embankment and water conservancy facilities, so that the embankment and environmental landscape engineering of the port service area in Hengqin New Area are part of the overall flood (tide) and drainage system of Hengqin New Area.

[0089] Hengqin New Area is located in the south of Zhuhai and is the largest island in Zhuhai. The development and construction and economic development of Hengqin New Area urgently require the embankments and water conservancy facilities to meet the planned flood control and drainage standards. As part of the overall flood (tide) and drainage system of Hengqin New Area, the embankment and environmental landscape engineering of the Hengqin New Area Port Service Area is very important for the embankment to meet the standards. Promoting the construction of embankment projects can effectively prevent floods and storm surges in front of the embankment, and form a coastal landscape belt along the embankment line, which not only protects the lives and property of the people on the island, but also provides people with leisure, entertainment and water-friendly space, providing a superior hardware environment for promoting the development of local tourism and attracting investment on Hengqin Island, and supporting the sustainable development of the regional economy and society. Therefore, it is very necessary to build the embankment to meet the standards. The task of the construction project is to protect the Hengqin New Area from offshore floods (tides), and to promptly drain rainwater from the new area and its hilly areas through relevant through-embankment buildings on the embankment, to ensure the flood (tide) safety of the Zhuhai Hengqin New Area; at the same time, in the construction of the embankment project, consideration should also be given to border defense and landscape requirements to form a coastal landscape belt to meet the development needs of local leisure and tourism industries.

[0090] The construction of the embankment and environmental landscape engineering of the Hengqin New Area Port Service Area includes an embankment of approximately 1.52 km in length on the northeast side of the roundabout, namely the Port Service Area (from the Shizimen Business District to the University of Macau), one flood drainage culvert, one rainwater culvert, and landscape greening projects from the embankment to the planned Qinhai East Road.

[0091] Through the analysis of the embankment project, it is found that the project is located in the port service area on the northeast side of Hengqin Island, that is, from the Shizimen Business District to the University of Macau, at the eastern end of the central ditch, in the planned Hengqin Port Service Area, and is arranged along the Shizimen waterway. The total length of the embankment is about 1.52km, including one flood drainage culvert and one rainwater culvert built on the embankment.

[0092] The dike axis is basically located according to the planned dike line layout shown in the flood control project planning map in the "Hengqin New Area Regulatory Detailed Plan", such as Figure 2 shown.

[0093] In order to solve the above-mentioned embankment problem, this embodiment adopts a port section embankment construction method that meets the requirements of flood control, drainage and ecological restoration. Figure 1 As shown, the specific steps include:

[0094] Step 1: Comprehensively analyze the current status of the project embankment and determine the layout orientation of the project embankment line; determine the embankment plan based on the layout orientation of the project embankment line and the surrounding environment information, and select the optimal embankment plan; the specific implementation operations of this step include:

[0095] The current status of the existing engineering embankments is briefly described as follows:

[0096] First, the existing embankment is low in height, and the flood (tide) control standard only meets the requirement of once in 5-20 years, and cannot meet the requirement of once in 100 years;

[0097] Second, the width of the crest of most embankment sections does not meet the 100-year flooding requirement;

[0098] Third, the embankment line is not straight and part of the bank wall has collapsed;

[0099] Fourth, the local stone masonry structure of the old bank wall is loose, with low strength and poor durability;

[0100] Fifth, the embankment foundation is weak and the overall stability is poor.

[0101] In summary, the existing engineering embankments have many problems, which are significantly different from the 100-year Class 1 embankment standard and need to be reinforced or rebuilt.

[0102] The layout of the embankment should be comprehensively considered based on planning conditions, design flood (tide) water levels, wind and wave factors, the current status of the embankment, the surrounding environment of the embankment section, geological conditions, etc. Especially in terms of ecological restoration: the Shizimen waterway outside the embankment of the port service area is narrow, with small winds and waves; the opposite bank faces Macau, China across the river, and the landscape requirements are high. Protected mangroves are planted on the beach outside the embankment; the geological conditions of this section of the embankment are poor, and the silt layer outside the embankment is thick.

[0103] Therefore, the embankment line is basically arranged along the old shoreline, but the cross-sectional structure of the embankment does not exceed the existing bank wall, so as not to occupy the river waters and damage the mangroves outside the embankment, and does not affect the flood control requirements and navigation requirements of the Shizimen waterway. The outer boundary of the embankment designed in this project is basically arranged along the old bank wall. The original bank wall is demolished and a new first-order retaining wall is built to make the outer edge of the embankment smooth and straight.

[0104] The layout of the engineering embankment line in this embodiment needs to take into account the following layout principles:

[0105] (1) The dikes must be arranged in accordance with the flood control project planning requirements of the Zhuhai Hengqin New Area Municipal Infrastructure Special Plan, and be coordinated with the Hengqin Island development and utilization plan and marine functional zoning;

[0106] (2) The layout of the dike line should conform to the law of beach evolution and be similar to the existing stable coastline morphology, which is conducive to the stability of the dike, the transport of water and sediment at the estuary, and the maintenance of the smooth flow and stability of the estuary;

[0107] (3) The dike layout should be based on the characteristics of the project dike section, take advantage of favorable terrain, and fully consider the changes in beach and beach conditions, water flow and wind and wave action mechanisms;

[0108] (4) The plan layout of the project should take into account the relationship between the project and adjacent projects, and the plan direction of the embankment line should consider smooth connection with the upstream and downstream embankments;

[0109] (5) The layout of the dike line should fully consider the existing traffic conditions and construction requirements to save project investment;

[0110] (6) To meet the needs of urban construction and landscape layout, when combined with roads, etc., they should be planned and arranged in a unified manner and coordinated with each other.

[0111] The selection of the embankment scheme of the seawall structure type should be based on the geographical location of the project area, the object of protection, the topographic and geological conditions of the embankment site, the embankment materials, tides, water flow, wind and wave characteristics, construction conditions, operation management, environmental landscape and project cost, and a comprehensive selection should be made after technical and economic comparison; in this embodiment, the existing conditions were referred to, and it was finally determined that the embankment scheme includes three types. These three cross-sectional types of embankment schemes are widely used in various places, and there are relatively rich experiences in design, construction, management, etc., namely slope type, upright type and composite type.

[0112] The embankment schemes for these three cross-section types are now further explained.

[0113] Plan A is a two-level platform composite embankment plan: According to the hydrological calculation results and border defense requirements, the embankment structure is determined to be a two-level vertical wall composite section, with the first platform at an elevation of 2.50m and a 1.2m high reinforced concrete solid wave-breaking wall on the outside.

[0114] Plan B is a first-level platform upright embankment plan: a platform is set up at an elevation of 4.30m on the top of the embankment, with a 10m wide road surface, which serves as a border patrol road and flood emergency rescue channel; the retaining wall uses gravity reinforced concrete, with a top elevation of 4.30m.

[0115] Plan C is a sloped embankment plan: a 3m wide wave-breaking platform is set at 2.00m from the top of the embankment, with a slope of 1:3 above and below the platform. A 30cm thick fence board is used for slope protection. The top of the embankment is 4.30m high and a 10m wide road surface is set as a border patrol road and flood emergency rescue channel.

[0116] The embankment scheme is designed by combining the geological conditions of the embankment base of different embankment sections and the existing structural type of the old embankment and selecting the optimal cross-section type based on the three preset cross-section types.

[0117] The optimal embankment solution can be determined by:

[0118] Set up a comparison table and labels, including: solution number, platform type name, solution advantages, and solution disadvantages;

[0119] Set the comparison table to show the advantages and disadvantages of the solutions and analyze the labels;

[0120] The optimal embankment plan is determined based on the geographical location of the embankment in the port service area, flood control safety, landscape planning, connection with municipal roads and management requirements.

[0121] Through the above technical solution, in the embodiment of the present invention, the comparison table is set to analyze the label ratio of the scheme advantages and disadvantages, which is set here by (number of scheme advantages × A% - number of scheme disadvantages × B%) / total number of scheme advantages and disadvantages × (A+B)%; A and B here are pre-set according to the importance of advantages and disadvantages in the overall construction during the implementation of the scheme, and will not be repeated here. See the comparison table below for specific content:

[0122]

[0123] After the above comparison and evaluation, the embankment section adopts Scheme A: two-level retaining wall composite. The cross-section form of this scheme takes into account the requirements of flood control safety, planning, connection with municipal roads and management.

[0124] Step 2: Design the engineering embankment and seawall according to the optimal embankment plan. The contents of the engineering embankment and seawall design include but are not limited to the determination of the seawall cross-section structure, soft soil foundation treatment, embankment stability calculation and culvert design;

[0125] like Figure 3 As shown, the specific implementation operations of this step include:

[0126] The determination of the seawall cross-section structure includes the following steps:

[0127] S200: Determine the structural elements of the seawall cross-section structure:

[0128] The cross-sectional structure of the seawall is mainly composed of the embankment body and the inner and outer slope protection. Its main structural elements include but are not limited to the embankment top elevation, the overtopping of the embankment top and the detailed structure of the embankment body. The details of the embankment body include but are not limited to: the width of the embankment top road, the outer slope platform and the protection type, the protection thickness and the unit weight of the block, etc. Therefore, the comparison of the cross-sectional structural scheme of the seawall is mainly to optimize and compare the various structural elements of the seawall. Among the various elements, the type of the outer slope protection and the size of the embankment slope ratio directly affect the climbing height of the wave on the slope, thereby affecting the design elevation of the embankment top. At the same time, the size of the embankment slope ratio is also related to the stability of the embankment body; by determining the appropriate cross-sectional structure, it is beneficial to enhance the stability of the seawall slope.

[0129] S210: According to the structural elements of the seawall cross-section structure, the embankment crest elevation is determined by optimizing and comparing the structural elements of the seawall cross-section structure, by formulating different outer embankment slope protection types and analyzing and comparing the corresponding embankment slope ratios. The embankment crest elevation is calculated according to the following formula:

[0130] Z P =h p +R F％ +A (1)

[0131] Among them, Z P represents the design embankment top elevation (m), hp represents the design high tide level (m), R F％ It indicates the wave run-up value (m) calculated based on the cumulative frequency F calculated based on the design wave. When designing based on wave overtopping allowed, F=13%; when designing based on wave overtopping not allowed, F=2%. A indicates the safety height increase (m). For the Class 1 embankment that allows wave overtopping, A is 0.50m; for the Class 1 embankment that does not allow wave overtopping, A is 1.0m.

[0132] Wave height R F％ Calculated according to the following formula:

[0133] R F％ =K Δ K v R1H 1％ K F (2)

[0134] In the formula, R F％ It represents the wave run-up value (m) with cumulative frequency F calculated according to the design wave, K Δ Indicates the roughness permeability coefficient related to the protective surface structure type, K V It represents the empirical coefficient related to wind speed and water depth in front of the dike, H 1％ Indicates the wave height value with cumulative frequency F = 1%, K F Indicates the conversion factor of the cumulative frequency of climbing. R1 indicates when K Δ =1.0m,H 1％ = Climbing height value (m) when 1.0m; the calculation formula of R1 is expressed as:

[0135] R1=1.24th(0.432M)+[(R1) m -1.029].R(M) (3)

[0136]

[0137]

[0138] R(M)=1.09M 3.32 exp(-1.25M) (6)

[0139] Where th represents the hyperbolic tangent function, M represents the function related to the m value of the slope, (R1) m It represents the maximum height increase corresponding to a certain d / L, d represents the water depth in front of the dike, L represents the average wavelength, H represents the wave height, sh represents the hyperbolic sine function, R1 represents the wave height increase, which is positive upwards from the design water level; R(M) represents the height increase function.

[0140] In order to meet the landscape requirements, the embankment slope protection type is preliminarily selected, the embankment top elevation is determined according to the above formula, and the output results are calculated. The output results include: embankment section name (port service area embankment), protection structure (reinforced concrete), rough seepage coefficient K Δ , safety height A(m), tide level h p , dike top elevation Z P and other information (corresponding cumulative frequencies);

[0141] The specific output results are shown in the following table:

[0142]

[0143] S220: According to the "Guangdong Province Seawall Engineering Design Guidelines (Trial)" (DB44 / T182-2004), when the seawall is designed to allow overtopping, the overtopping volume at the top of the embankment should be calculated and verified. The overtopping volume at the top of the embankment is the overtopping water volume per unit embankment width per unit time. Under windless conditions, the overtopping water volume can be calculated according to DB44 / T182-2004 as follows:

[0144]

[0145] Where q represents the overtopping amount, represents the average wave height in front of the dike, T represents the effective wave period, g represents the gravitational acceleration, It indicates the steepness of waves in front of the dike, L indicates the wavelength, when the slope of the sea dike is 1:0.4, the A and B coefficients can be found in Table K.0.1-2 of the Guidelines.

[0146] Under windy conditions, the overtopping water volume is obtained by multiplying the overtopping water volume under windless conditions by the wind correction factor K′. The wind correction factor K′ is expressed as:

[0147] K′=1.0+W f (H C / R+0.1)sinθ (8)

[0148] Where W f It represents the coefficient related to wind speed, θ represents the slope angle of the seawall facing the sea, and R represents the wave run-up value on the seawall.

[0149] The calculation results of overtopping water volume include: embankment section name (port service area embankment), water level (P = 1%), effective wave height, average wave period, overtopping water volume and wall top elevation.

[0150] The calculation results of specific overtopping amount are shown in the following table:

[0151]

[0152] S230: The detailed structure of the embankment in this embodiment includes but is not limited to:

[0153] (1) Width of dike top road: The width of dike top road that meets flood control requirements is 2.5m. Due to the presence of bridge piers under the Lotus Bridge, the width of dike top road that meets flood control requirements is 2.5-5.5m.

[0154] (2) Pavement structure on the top of the embankment: The pavement on the top of the embankment is determined to be a sesame-ash burnt granite block pavement; under the pavement, there is a 30mm thick, 1:3 dry hard cement mortar, 150mm C30 plain concrete, and a 200mm thick natural graded crushed stone cushion layer;

[0155] (3) Level 1 platform: A level 1 platform is to be set up at an elevation of 2.5m for border patrol. A 10m wide area including retaining walls and wave-breaking walls is to be used as a border warning area at the level 1 platform. 250mm C30 plain concrete and 300mm thick natural graded crushed stone cushion are used for the border warning area (level 1 platform). The net width of the platform road is 8.8m, which meets the requirements for patrol vehicles to pass. A 1.2m high reinforced concrete solid wave-breaking wall is set up on the outside.

[0156] (4) Primary and secondary retaining walls: Two levels of retaining walls are set at elevations of 2.50m and 4.10m respectively. Specifically:

[0157] The existing quay wall will be demolished and rebuilt to an elevation of -0.80m;

[0158] A new primary retaining wall is built above 1.00m elevation, using a cast-in-place cantilever reinforced concrete structure. The upper part of the wall facing the water adopts an anti-arc to suppress waves and prevent climbing. Below 1.00m elevation, prefabricated concrete blocks are used, with a thickness of 1.50m. The foundation of the prefabricated concrete blocks is made of crushed stone with an average thickness of 50mm and two-piece stone with an average thickness of 250mm.

[0159] The secondary retaining wall is made of cantilever reinforced concrete with a top elevation of 4.30m. The upper surface of the wall facing the water adopts anti-arc wave suppression.

[0160] Among them, the soft soil embankment foundation treatment includes the following steps:

[0161] The basic treatment of the embankment in the port area is as follows:

[0162] (I) High-pressure jet grouting (high-pressure jet grouting piles) is used to treat the thick silt layer of the embankment foundation. The thick silt layer refers to a soil layer with high natural water content, plasticity, low strength, high compressibility, low shear strength, low permeability, and rheological and thixotropic characteristics. The thick silt layer is prone to cause foundation settlement and instability; specifically:

[0163] (1) High-pressure jet grouting pile design, including:

[0164] (a) Plane layout of high-pressure jet grouting piles

[0165] The columnar reinforcement type with square piles is adopted, with effective pile diameter D = 0.6m, spacing 1.6m × 1.6m, and replacement rate 11.0%;

[0166] (b) Determination of single pile length

[0167] Since the jet grouting piles designed in this scheme are mainly used to improve the anti-sliding stability of the earth embankment, according to the calculation results of the embankment slope stability, the length of the mixing pile is 28.5m;

[0168] (c) Equivalent strength index of jet grouting pile composite foundation

[0169] The equivalent strength index of the foundation after jet grouting treatment can be calculated as follows: C = C1m f +C2(1-m f ) (9)

[0170]

[0171] Where, C is the equivalent strength index cohesion of the foundation after jet grouting pile treatment; φ is the equivalent strength index internal friction angle of the foundation after jet grouting pile treatment, m f represents the area replacement rate, C1 represents the cohesion of the pile body, C2 represents the cohesion of the soft soil layer, φ1 represents the internal friction angle of the pile body, φ2 represents the internal friction angle of the soft soil layer, K1 represents the stiffness of the rotary jet pile, and K2 represents the stiffness of the soft soil around the pile; β is the ratio of the settlement S1 of the pile to the settlement S2 of the soft soil around the pile. For fill, generally S1<S2, and β=0.5 can be taken. For rigid foundation, S1=S2, β=1.

[0172] The pile cohesion C1 is determined by the following formula:

[0173]

[0174] In the formula, f cu represents the average cubic compressive strength of the indoor reinforced test block with the same cement-soil ratio as the jet-jet pile body under standard curing conditions at 28 days of age, η represents the pile body strength reduction coefficient, It represents the internal friction angle of pile depth.

[0175] (ii) Use CFG piles to treat the silt layer at the embankment foundation; specifically:

[0176] CFG pile design: adopts a columnar reinforcement type with square piles, with a pile diameter of D=0.40m, a spacing of 1.5m×1.5m, and a pile length of 15.5-28.5m depending on the stability of the embankment slope.

[0177] The embankment stability calculation includes the following steps:

[0178] The levee stability in this embodiment refers to the anti-sliding stability of the levee slope; the anti-sliding stability of the levee slope can be calculated using the Swedish arc sliding method, which is divided into the total stress method and the effective stress method;

[0179] The total stress method calculation formula is as follows:

[0180]

[0181] Where K represents the anti-sliding stability safety factor, W 1i , W 2i , W 2i ', W 3i 'represents the natural weight of the soil above the infiltration line of the i-th soil strip, the saturated weight of the soil between the infiltration line and the outer slope water level, the floating weight of the soil between the infiltration line and the outer slope water level, and the floating weight of the soil below the outer slope water level (kN); b i represents the width of the i-th soil strip (m), α i represents the angle (°) between the radius passing through the midpoint of the bottom of the i-th soil strip and the vertical direction (gravity direction); C i , represents the total stress shear strength index (kPa, °) of the soil at the bottom of the ith soil strip calculated according to equations (9) and (10).

[0182] The anti-sliding stability safety factor shall meet the following requirements: Normal operating conditions: K ≥ 1.30; Emergency operating conditions I: K ≥ 1.20; Emergency operating conditions II (earthquake): K ≥ 1.10;

[0183] According to DB44 / T182-2004, the embankment of this project should be calculated for settlement. The settlement calculation of the old embankment reinforcement generally only considers the settlement caused by the new load. The settlement calculation includes the completed settlement and residual settlement of the embankment, and the calculation results are corrected according to regional experience. In order to simplify the calculation, the working condition at the average low tide level is used as the load calculation condition.

[0184] The calculation formula for calculating the main consolidation settlement using the compression modulus is:

[0185]

[0186] In the formula, S c represents the main consolidation settlement (mm), ΔP i It represents the additional stress increment at each layer in the foundation, E si represents the compression modulus, Δh i represents the layer thickness (mm), I represents the number of soil layers in the compression layer range, and i represents the i-th soil layer in the compression layer range;

[0187] The calculation formula for the total settlement of the foundation is:

[0188] S=m x S c (14)

[0189] Where S represents the final settlement (mm), m x It represents the settlement correction factor;

[0190] The calculation formula for foundation settlement at any time is:

[0191] S=(m x -1+U t )S c (15) In the formula, S t Indicates the foundation settlement at any time (mm);

[0192] The calculation formula for the average total consolidation degree of the foundation is:

[0193] U t =1-(1-U r )(1-U z ) (16)

[0194] Where U t , U r , U z They are the average total consolidation degree, radial average consolidation degree and vertical average consolidation degree of the foundation respectively;

[0195] The calculated depth of the embankment foundation compression layer is determined based on the ratio of the additional stress of the soil at the calculated level to the self-weight stress being no more than 0.15 times.

[0196] Among them, culvert design includes the following steps:

[0197] Calculate the vertical bearing capacity of a single CFG pile R according to the following formula: a :

[0198]

[0199] In the formula, R a represents the characteristic value of the vertical bearing capacity of a single pile, μ p represents the circumference of the pile, A p represents the cross-sectional area of ​​the pile, I represents the number of soil layers divided within the length of the pile, and q xi represents the characteristic value of the lateral resistance of the i-th layer of soil within the pile length range, l i represents the thickness of the i-th soil layer within the pile length, q p It represents the uncorrected characteristic value of the bearing capacity of the foundation soil at the pile end;

[0200] The bearing capacity of the composite foundation f is calculated according to the following formula spk :

[0201]

[0202] In the formula, f spk represents the characteristic value of composite foundation bearing capacity, m c represents the characteristic value of the bearing capacity of the composite foundation, β represents the reduction factor of the bearing capacity of the soil between piles, and f sk It represents the characteristic value of soil bearing capacity between piles.

[0203] Based on the bearing capacity of composite foundation f spk , carry out culvert design.

[0204] Step 3: According to the design of the embankment and seawall of the project, determine the construction content and construction method of the project to ensure that a highly adaptable port service area embankment with protective and ecological functions is finally obtained.

[0205] The construction contents include earth excavation, earth filling, foundation treatment, concrete pouring, mortar masonry and greening;

[0206] The construction methods include:

[0207] The main construction of the project embankment: earth excavation, earth backfilling, CFG piles, high-pressure jet grouting piles, mortar block stone, concrete pouring, riprap, etc.;

[0208] Main construction of buildings: earth excavation and backfilling, CFG piles, installation of precast concrete parts, riprap, etc.

[0209] This embodiment aims at the development and economic development of Hengqin New Area. In addition to designing embankments and water conservancy facilities that meet the planned flood control and drainage standards, it ensures that the project construction effectively defends against floods and storm surges in front of the embankment, and forms a coastal landscape belt along the embankment line. It not only protects the lives and property of the people on the island, but also provides people with leisure, entertainment and water-friendly space, provides a superior hardware environment for promoting the development of local tourism and attracting investment on Hengqin Island, and supports the sustainable development of the regional economy and society.

[0210] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0211] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration, characterized in that: The following steps are involved: Step 1: Determine the layout orientation of the project embankment line according to the current status of the project embankment; Determine the cross-section type of embankment plan based on the project embankment layout orientation and surrounding environment information; Step 2: Design the engineering embankment and seawall according to the cross-section type embankment scheme. The engineering embankment and seawall design includes: seawall cross-section structure design, soft soil embankment foundation treatment that meets the requirements of embankment slope stability, and culvert design; Step 3: Determine the construction content and method based on the embankment and seawall design.

2. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 1, characterized in that: The cross-sectional structure of the seawall includes the embankment body and the inner and outer embankment slope protection surfaces; The structural elements of the seawall cross-section structure include the elevation of the top of the seawall and the detailed structure of the seawall body; The seawall cross-section structure design includes: S200: Select the outer embankment slope protection type according to the cross-sectional embankment plan; determine the embankment crest elevation in the structural element of the seawall cross-sectional structure by optimizing and comparing the outer embankment slope protection type and embankment slope ratio; S210: Determine the detailed structure of the seawall cross-section structure; S220: Design the seawall cross-section structure using the determined crest elevation and detailed structure of the embankment.

3. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 2, characterized in that: The top elevation of the embankment is calculated according to the following formula: Z P =h p +R F％ +A(1) In the formula, Z P represents the design embankment top elevation, h p Indicates the design high tide level, R F％ It represents the wave run-up value with cumulative frequency F calculated according to the design wave, and A represents the safety heightening; Among them, the wave height value R F％ Calculated according to the following formula: R F％ =K Δ K V R1H 1％ K F (2) In the formula, K Δ Indicates the rough permeability coefficient related to the type of embankment slope protection, K V It represents the empirical coefficient related to wind speed and water depth in front of the dike, H 1％ Indicates the wave height value with cumulative frequency F = 1%, K F Indicates the conversion factor of the cumulative frequency of climbing; R1 means when K Δ =1.0m,H 1％ = The climbing height value when 1.0m; the calculation formula of R1 is expressed as: R1=1.24th(0.432M)+[(R1) m -1.029]·R(M) (3) R(M)=1.09M 3.32 exp(-1.25M) (6) Where th represents the hyperbolic tangent function, M represents the function related to the m value of the slope, (R1) m It represents the maximum value of the creepage corresponding to a certain d / L, d represents the water depth in front of the dike, L represents the wavelength, H represents the wave height, sh represents the hyperbolic sine function, R1 represents the wave creepage, which is positive upwards from the design water level; R(M) represents the creepage function; When the seawall is designed according to the allowable overtopping, the overtopping volume at the top of the seawall shall be calculated and verified. The overtopping volume at the top of the seawall is the overtopping water volume per unit seawall width per unit time. Under windless conditions, the overtopping water volume is calculated as follows: Where q represents the overtopping amount, represents the average wave height in front of the dike, T represents the effective wave period, g represents the gravitational acceleration, It indicates that the wave is steep in front of the dike, and L indicates the wavelength; Under windy conditions, the overtopping water volume is obtained by multiplying the overtopping water volume under windless conditions by the wind correction factor K′. The wind correction factor K′ is expressed as: K′=1.0+W f (H C / R+0.1)sinθ (8) Where W f It represents the coefficient related to wind speed, θ represents the slope angle of the seawall facing the sea, and R represents the wave run-up value on the seawall.

4. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 2, characterized in that: The detailed structure of the seawall cross-section structure includes: the width of the embankment road, the embankment road surface structure, the first-level platform, the first-level retaining wall and the second-level retaining wall; The detailed structure of the seawall body for determining the cross-sectional structure of the seawall specifically includes: Determine the width of the levee crest road that meets flood control requirements; Determine the main structure of the embankment top road surface and the cushion structure under the embankment top road surface; Determine the elevation of the first-level platform and determine the structure of the first-level platform; Determine the elevation and structure of the primary retaining wall; Determine the setting elevation of the secondary retaining wall and determine the structure of the secondary retaining wall.

5. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 4, characterized in that: The first-level platform is used as a border defense zone, including retaining walls and wave-breaking walls, and the first-level platform is set at an elevation of 2.5m; The setting elevation of the primary retaining wall is 2.50m. The primary retaining wall adopts a cast-in-place cantilever reinforced concrete structure. The upper water surface of the primary retaining wall adopts an anti-arc wave suppression structure. Concrete prefabricated blocks are used below the elevation of 1.00m of the primary retaining wall. The setting elevation of the secondary retaining wall is 4.10m. The secondary retaining wall adopts cantilever reinforced concrete, and the wall top elevation is 4.30m. The upper water surface of the secondary retaining wall adopts an anti-arc wave suppression structure.

6. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 1, characterized in that: The soft soil embankment foundation treatment specifically includes the following steps: The step of primary treatment of the silt layer at the embankment foundation by high pressure jet grouting method; The steps of secondary treatment of the silt layer at the embankment foundation using CFG piles.

7. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 6, characterized in that: The step of primary treatment of the embankment foundation silt layer by high pressure jet grouting method comprises: Determine the plane layout of the high-pressure jet grouting piles, which adopts a columnar reinforcement type with square piles; According to the requirements of embankment slope stability, determine the length of a single high-pressure jet grouting pile; According to the plane layout and the length of a single high-pressure jet grouting pile, cement slurry is sprayed into the silt layer of the embankment foundation with a high-pressure rotating nozzle to mix with the silt layer of the embankment foundation, thereby reinforcing the silt layer of the embankment foundation; The steps of using CFG piles to perform secondary treatment on the silt layer at the dike foundation include: Determine the reinforcement type of CFG piles, which adopts a columnar reinforcement type with square piles; According to the requirements of embankment slope stability, determine the length of a single CFG pile; The silt layer at the embankment foundation is reinforced according to the reinforcement type of CFG piles and the length of a single CFG pile.

8. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 7, characterized in that: The embankment slope stability requirements are determined according to the following steps: Calculate the total stress shear strength index after high-pressure jet grouting treatment; The embankment slope stability is calculated according to the following formula: Where K represents the anti-sliding stability factor of the embankment slope, W 1i , W 2i , W 2i ', W 3i 'represent the natural weight of the soil above the infiltration line of the i-th soil strip, the saturated weight of the soil between the infiltration line and the outer slope water level, the floating weight of the soil between the infiltration line and the outer slope water level, and the floating weight of the soil below the outer slope water level; b i represents the width of the i-th soil strip, α i represents the angle between the radius through the midpoint of the bottom of the i-th soil strip and the direction of gravity; C i , It represents the total stress shear strength index of the soil at the bottom of the i-th soil strip; The anti-sliding stability safety factor of the embankment slope meets the following requirements: Normal operating conditions: K ≥ 1.30; Special application conditions Ⅰ: K ≥ 1.20; Special application conditions II: K ≥ 1.10; According to the requirements of embankment slope stability, the length of a single high-pressure jet grouting pile is determined, specifically including: Initialize the length of a single high-pressure jet grouting pile; Calculate the current embankment slope stability. If the current embankment slope stability meets the strict requirements, the pile length is the pile length of a single high-pressure rotary jet pile. If the current embankment slope stability does not meet the strict requirements, adjust the pile length of the single high-pressure rotary jet pile and repeat this step.

9. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 8, characterized in that: The total stress shear strength index after high-pressure jet grouting treatment is calculated as follows: C=C1m f +C2(1-m f ) (9) Where, C is the equivalent strength index cohesion of the foundation after jet grouting pile treatment; φ is the equivalent strength index internal friction angle of the foundation after jet grouting pile treatment, m f represents the area replacement rate, C1 represents the cohesion of the pile body, C2 represents the cohesion of the soft soil layer, φ1 represents the internal friction angle of the pile body, φ2 represents the internal friction angle of the soft soil layer, K1 represents the rigidity of the jet grouting pile, and K2 represents the rigidity of the soft soil part around the pile; β represents the ratio of the settlement S1 of the pile to the settlement S2 of the soft soil part around the pile. For fill soil, generally S1<S2, and β=0.5 can be taken. For rigid foundation, S1=S2, β=1; The pile cohesion C1 is determined by the following formula: In the formula, f cu represents the average cubic compressive strength of the indoor reinforced test block with the same cement-soil ratio as the jet-jet pile body under standard curing conditions at 28 days of age, η represents the pile body strength reduction coefficient, It represents the internal friction angle of pile depth.

10. A method for rebuilding a port section embankment that meets the requirements of flood control, drainage and ecological restoration according to claim 7, characterized in that: The culvert design specifically includes: The vertical bearing capacity of a single CFG pile R is calculated according to the following formula: a : In the formula, R a represents the characteristic value of the vertical bearing capacity of a single pile, μ p represents the circumference of the pile, A p represents the cross-sectional area of ​​the pile, I represents the number of soil layers divided within the length of the pile, and q xi represents the characteristic value of the lateral resistance of the i-th layer of soil within the pile length range, l i represents the thickness of the i-th soil layer within the pile length, q p It represents the uncorrected bearing capacity characteristic value of the foundation soil at the pile end; The bearing capacity of the composite foundation f is calculated according to the following formula spk : In the formula, f spk represents the characteristic value of the bearing capacity of the composite foundation, m c represents the characteristic value of the bearing capacity of the composite foundation, β represents the reduction factor of the bearing capacity of the soil between piles, and f sk represents the characteristic value of soil bearing capacity between piles; Based on the bearing capacity of composite foundation f spk , carry out culvert design.

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