Soft soil foundation treatment combined structure of riprap and reclamation transition section
By zoning the riprap and reclamation transition section and combining a variety of foundation treatment techniques, the problem of controlling post-construction differential settlement in the transition zone was solved, the overall coordination of foundation settlement was achieved, and the settlement difference requirements were met.
Patent Information
- Application Number
- CN202422968772.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-10-21
- Estimated Expiration
- 2034-12-03
AI Technical Summary
In the transition section of riprap reclamation, due to different land formation techniques, it is difficult to control the post-construction differential settlement in the transition zone, which affects the overall settlement coordination of the foundation.
The cofferdam area, mud receiving area, right cofferdam expansion area, left cofferdam expansion area, direct filling area, channel expansion area, closed channel area, silt removal and replacement area are used for zoning treatment. Combined with high-pressure jet grouting piles, vibro-jet crushed stone piles, vacuum preloading, dynamic compaction of different energy levels and preloading with pile load, a treatment combination structure with coordinated foundation stiffness and deformation is formed.
A smooth transition of foundation stiffness between adjacent areas was achieved, ensuring overall deformation coordination of post-construction foundation settlement and ensuring that the settlement difference between adjacent areas was within 0.5%.
Smart Images
Figure CN223458785U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a kind of soft soil foundation treatment combination structures of riprapping reclamation transition section. BACKGROUND
[0002] With the rapid development of economy, land resources are increasingly strained, and the demand for reclamation in coastal areas is increasing. China has made a lot of technical innovations in the field of reclamation engineering technology, including cofferdam technology, dredging technology, foundation treatment technology, etc.
[0003] According to the different use functions during the operation period, different land formation processes are used in large-area reclamation projects. Before each land area is formed, a cofferdam is formed according to the boundaries of the land formation process to divide each land formation area. For areas with strict settlement control during the operation period, the process of dredging and replacement is generally used first, which is the dredging and replacement area. For areas that need to bear upper loads and allow some settlement, the process of direct riprapping land formation is generally used, which is the direct filling area. For areas that do not bear large loads during the use period, the sludge is generally directly filled from the dredging and replacement area, which is the sludge area. Dredging is generally in the form of slope dredging. To avoid the re-entry of sludge into the dredged area during the riprapping backfilling process, an enclosed channel area is formed after dredging to protect the dredged area from the impact of subsequent riprapping compaction. This results in a transition area between the dredging and replacement area and the cofferdam. The transition area generally uses the direct filling land formation process, and the distribution of sludge layer is uneven due to the influence of the dredging slope. The transition area and the land formation areas on both sides of the cofferdam form a transition section. Due to the different land formation processes in the transition section, it is difficult to control the post-construction differential settlement.
[0004] Therefore, a soft soil foundation treatment combination structure for riprapping reclamation transition section is proposed to solve the above problems. UTILITY MODEL CONTENTS
[0005] The utility model aims to overcome the defects of the prior art and provide a soft soil foundation treatment combination structure for riprapping reclamation transition section, which smoothly transitions the foundation stiffness of each adjacent area and ensures the overall deformation coordination of post-construction settlement of the foundation.
[0006] The technical solution to achieve the above-mentioned purpose is: a soft soil foundation treatment combination structure for riprapping reclamation transition section, comprising a cofferdam area, a sludge area on the right side of the cofferdam area, a right cofferdam outer expansion area between the right side of the cofferdam area and the sludge area, a left cofferdam outer expansion area on the left side of the cofferdam area, a direct filling area on the left side of the left cofferdam outer expansion area, a channel outer expansion area on the left side of the direct filling area, an enclosed channel area on the left side of the channel outer expansion area, and a dredging and replacement area on the left side of the enclosed channel area.
[0007] Preferably, a first stone layer is filled and placed after dredging in the dredging and replacement area, and a high-energy level dynamic compaction process is used for treatment.
[0008] Preferably, the closed channel area is filled with a second layer of stone after dredging and is treated by low-energy dynamic compaction.
[0009] Preferably, the channel extension area is filled with a third layer of stone after dredging and is treated by high-pressure rotary jet grouting piles with variable pile length.
[0010] Preferably, the direct filling area is filled with a fourth layer of stone and is reinforced by vibro-replacement stone columns.
[0011] Preferably, the left cofferdam extension area is filled with a fifth layer of stone and is treated by high-pressure rotary jet grouting piles.
[0012] Preferably, the cofferdam area is filled with a sixth layer of stone after dredging and is treated by low-energy dynamic compaction.
[0013] Preferably, the right cofferdam extension area is filled with a seventh layer of stone and is reinforced by vibro-replacement stone columns.
[0014] Preferably, the silt area is formed by hydraulic fill and is reinforced by vacuum preloading combined with ultra-high surcharge.
[0015] Preferably, the dredging and replacement area experiences a small average settlement S1 during the service period; the closed channel area experiences a slight average settlement S2 during the service period; the channel extension area experiences a mild average settlement S3 during the service period; the direct filling area experiences a moderate average settlement S4 during the service period; the left cofferdam extension area experiences a mild average settlement S5 during the service period; the cofferdam area experiences a slight average settlement S6 during the service period; the right cofferdam extension area experiences a moderate average settlement S7 during the service period; and the silt area experiences a significant average settlement S8 during the service period.
[0016] Settlement of each ground treatment partition ΔPi is the average additional stress of the ith layer of soil, MPa; Es i is the compression modulus of the ith layer of soil, MPa; hi is the thickness of the ith layer of soil.
[0017] At the same time, the average differential settlement value between adjacent areas satisfies the following requirements:
[0018] |Sk-Sk+1| / ΔH<5 ‰
[0019] Where k is the partition number, taking an integer from 1 to 7, ΔH is the midpoint horizontal distance between K area and k+1 area; Sk is the partition settlement.
[0020] The soft soil foundation treatment combined structure of the rockfill reclamation transition section has the advantages that the control concept of foundation rigidity and deformation coordination is adopted, the foundation deformation characteristics of different treatment processes such as high-pressure rotary jet grouting pile, vibration compaction gravel pile, vacuum preloading, different energy level dynamic compaction, and pile preloading are fully utilized, the foundation treatment combined structure gradually transiting from the dredging replacement area to the dredging slope, the blasting and silt extrusion cofferdam, and the silt receiving area is formed, the foundation treatment process corresponding to the land formation mode of different areas is adopted, the foundation rigidity of the adjacent areas after treatment is smoothly transited, and the overall deformation coordination of the post-construction settlement of the foundation is ensured. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 is a schematic view of the soft soil foundation treatment combined structure of the rockfill reclamation transition section of the utility model.
[0022] In the figure: 1, cofferdam area; 2, silt receiving area; 3, right cofferdam extension area; 4, left cofferdam extension area; 5, straight filling area; 6, channel extension area; 7, closed channel area; 8, dredging replacement area; 9, first stone layer; 10, second stone layer; 11, third stone layer; 12, fourth stone layer; 13, fifth stone layer; 14, sixth stone layer; 15, seventh stone layer. DETAILED DESCRIPTION
[0023] The technical scheme of the utility model will be described clearly and completely in combination with the drawings. In the description of the utility model, it should be explained that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is the orientation or position relationship based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as limiting the utility model. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying the importance of the opposite.
[0024] The utility model will be further described in combination with the drawings.
[0025] As shown in Figure 1 A soft soil foundation treatment combined structure of a rockfill reclamation transition section, comprising a cofferdam area 1, the right side of the cofferdam area 1 is a silt receiving area 2, a right cofferdam extension area 3 is arranged between the right side of the cofferdam area 1 and the silt receiving area 2; a left cofferdam extension area 4 is arranged on the left side of the cofferdam area 1, a straight filling area 5 is arranged on the left side of the left cofferdam extension area 4, a channel extension area 6 is arranged on the left side of the straight filling area 5, a closed channel area 7 is arranged on the left side of the channel extension area 6, and a dredging replacement area 8 is arranged on the left side of the closed channel area 7.
[0026] Specifically, the first stone layer 9 is filled in the dredging and replacement area 8 after dredging, and high-energy level dynamic compaction process is performed. The dredging and replacement area 8 is formed by removing the 9-14m thick silt and silt soil on the original seabed surface and replacing it with the first stone layer 9 to the 2.7m elevation, forming a land area with a total thickness of 20-22.5m. Since there is no silt soil after replacement, high-energy dynamic compaction process with a ramming energy of 18000kN·m is used for treatment during foundation treatment, and the soil performance after treatment is good. Due to the high strength of the riprap layer, it has been compacted after high-energy dynamic compaction, so it has a small average settlement during use.
[0027] Specifically, the second stone layer 10 is filled in the closed channel area 7 after dredging, and low-energy level dynamic compaction process is performed. After the dredging reaches the design requirements and is accepted and qualified, a 10m wide channel area is first filled along the dredging bottom line to form a closed channel area 7 with a top width of 10m, and then expanded outward to 40m according to the principle, to form a closed channel area 7, to ensure that the silt does not enter the dredging and replacement area 8. And fill the second stone layer 10, in order to reduce the differential settlement of the two areas, the closed channel area 7 uses 6000kN·m low-energy dynamic compaction to allow slight settlement, to transition to the channel expansion area 6.
[0028] Specifically, the third stone layer 11 is filled in the channel expansion area 6 after the dredging bottom boundary is formed, and high-pressure rotary jet grouting pile treatment is performed. The channel expansion area 6 is formed by expanding the closed channel area 7 by 30m, with a dredging slope line at the bottom, and uneven thickness of underlying silt, which is prone to cause large differential settlement and affect normal use. Variable-length high-pressure rotary jet grouting piles are used for treatment, with a pile length of 15-25m, a pile diameter of 0.6m, a spacing of 1m, and a hardened cement slurry strength not less than the compressive strength of the gravel. The high-pressure rotary jet grouting pile treatment forms a pile foundation structure, which can effectively share the load of the upper riprap layer, and the high-pressure rotary jet grouting pile can have a slight settlement, effectively transitioning from the closed channel area 7 to the direct filling area 5.
[0029] Specifically, the fourth stone layer 12 is directly filled in the direct filling area 5, and the foundation is reinforced with vibro-replacement stone columns. The direct filling area 5 is formed by directly filling the mountain soil and rock on land. The foundation treatment uses vibro-replacement stone columns: pile diameter 1.2m, pile spacing 2.5m, arranged in a regular triangle, replacement rate 20.9%, pile length 25m. After the construction of the vibro-replacement stone columns is completed, the foundation treatment area is subjected to pressure loading, with a pressure loading height of 3.0m, divided into 2 levels, each level loading height 1.5m, slope ratio 1:1.5, loading 1 month, loading interval not less than 15 days, constant load pressure loading 3 months. After treatment by stone columns combined with preloading, the soft soil layer under the riprap layer can be drained and consolidated, and the stone columns can share the load of the upper part, with moderate settlement during use, effectively transitioning from the channel expansion area 6 to the left cofferdam expansion area 4.
[0030] Specifically, the fifth stone layer 13 is directly filled in the left cofferdam extension area 4, and high-pressure rotary jet pile treatment is performed. In order to prevent the silt in the silt area 2 from being squeezed into the cofferdam area 1, it is necessary to build the cofferdam area 1 to form a closed structure. However, since the surrounding rock area is formed by blasting and silt squeezing, the foundation stiffness is large, and the deformation during use is small. In order to ensure the overall coordinated deformation of the foundation during use, the left cofferdam extension area 4 is set on the left side of the surrounding rock, and high-pressure rotary jet pile is used for treatment, with a pile diameter of 0.6m and a spacing of 1m. The strength of the hardened cement slurry is not less than the compressive strength of the gravel, so that the post-construction settlement is less than the small settlement of the direct filling area.
[0031] Specifically, the sixth stone layer 14 is filled in the cofferdam area 1 after blasting and silt squeezing, and low-energy level dynamic compaction process is performed. The soil performance of the cofferdam area 1 is good, and in order to reduce the differential settlement between the cofferdam and the extension areas on both sides of the cofferdam, 6000kN·m low-energy level dynamic compaction is used for treatment, and micro-settlement occurs during use.
[0032] Specifically, the seventh stone layer 15 is directly filled in the right cofferdam extension area 3, and the foundation is reinforced by vibroflotation gravel pile. Since the settlement of the silt area 2 is large and the settlement of the cofferdam area 1 is small, the right cofferdam extension area 3 is needed to connect the two areas to ensure the overall coordinated settlement. The right cofferdam extension area 3 is treated by vibroflotation gravel pile combined with preloading, with a pile diameter of 1.2m, a pile spacing of 2.5m, a triangular arrangement, a replacement rate of 20.9%, a pile length of 25m, and a preloading height of 3m. Moderate settlement occurs after construction, which can effectively transition from the cofferdam area 1 to the silt area 2.
[0033] Specifically, the silt area 2 is formed by dredging and filling the silt in the silt filling area, and the whole is composed of silt and silt soil. The dredged silt and the original sea mud have the characteristics of high water content, large void ratio, high compressibility, low density, low strength, poor permeability, and uneven soil body. The settlement during use is obvious. Since the right cofferdam extension area 3 has been set to form a transition section, the silt area 2 can be treated by vacuum combined preloading, but the preloading height of the silt area needs to be increased to reduce the influence of the settlement during use. Plastic drainage board is arranged in a triangular shape with a spacing of 0.8m and an average length of 23m. The vacuum degree under the membrane reaches more than 85kPa, and the vacuum preloading is not less than 30 days after full loading. The combined preloading is then performed with a preloading height of 9.0m.
[0034] Specifically, the dredging replacement area 8 is treated by high-energy level dynamic compaction, and a small average settlement S1 occurs during the service period; the closed channel area 7 is treated by low-ramming-energy dynamic compaction, and a slight average settlement S2 occurs during the service period; the channel expansion area 6 is treated by high-pressure jet grouting piles with variable pile lengths, and the compression strength of hardened cement slurry is not less than that of the gravel, and a slight average settlement S3 occurs during the service period; the direct filling area 5 is treated by vibro-replacement stone column combined with preloading, and a moderate average settlement S4 occurs during the service period after the treatment of the vibro-replacement stone column; the left cofferdam expansion area 4 is treated by high-pressure jet grouting piles, and the compression strength of hardened cement slurry is not less than that of the gravel, and a slight average settlement S5 occurs during the service period; the cofferdam area 1 is treated by low-ramming-energy dynamic compaction, and a slight average settlement S6 occurs during the service period; the right cofferdam expansion area 3 is treated by vibro-replacement stone column combined with preloading, and a moderate average settlement S7 occurs during the service period; and the silt collection area 2 is treated by vacuum combined with preloading, and the preloading height is greater than that of the right cofferdam expansion area 3, and a significant average settlement S8 occurs during the service period.
[0035] Settlement of each ground treatment partition ΔPi is the average additional stress of the ith layer of soil, MPa; Es i is the compression modulus of the ith layer of soil, MPa; hi is the thickness of the ith layer of soil.
[0036] At the same time, the average differential settlement value between adjacent areas should meet the following requirements:
[0037] |Sk-Sk+1| / ΔH<5‰
[0038] Wherein, k is the partition number, taking an integer of 1-7, ΔH is the midpoint horizontal distance between K area and k+1 area; Sk is the settlement of the partition. The original areas are all sea areas, and the land formation processes are different, resulting in different underground geology. During use, the settlement of the entire transition area should be continuous, so the settlement Sk of adjacent areas should meet the requirement of 5 / 1000.
[0039] The soft soil foundation treatment combination structure of the riprap sea reclamation transition section adopts the control concept of coordination of foundation stiffness and deformation, fully utilizes the foundation deformation characteristics of different treatment processes such as high-pressure jet grouting pile, vibro-replacement stone column, vacuum preloading, dynamic compaction of different energy levels, and preloading, and forms a foundation treatment combination structure gradually transitioning from the dredging replacement area to the dredging slope, the blasting and extruding cofferdam, and the silt collection area; according to the land formation methods of different areas, the corresponding foundation treatment process is adopted, the foundation stiffness of the treated adjacent areas smoothly transitions, and the overall deformation coordination of the post-construction settlement of the foundation is ensured.
[0040] The above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A soft soil foundation treatment composite structure for a riprap and land reclamation transition section, characterized in that: The application relates to a cofferdam area (1), a silt receiving area (2) is arranged on the right side of the cofferdam area (1), a right cofferdam extension area (3) is arranged between the right side of the cofferdam area (1) and the silt receiving area (2), a left cofferdam extension area (4) is arranged on the left side of the cofferdam area (1), a straight filling area (5) is arranged on the left side of the left cofferdam extension area (4), a channel extension area (6) is arranged on the left side of the straight filling area (5), a closed channel area (7) is arranged on the left side of the channel extension area (6), and a dredging and replacement area (8) is arranged on the left side of the closed channel area (7).
2. The soft ground improvement composite structure for the riprap sea filling transition section according to claim 1, characterized by, The first stone layer (9) is filled in the dredging and replacement area (8) after dredging, and high-energy level dynamic compaction process treatment is carried out.
3. The soft ground improvement composite structure for riprap sea filling transition section according to claim 1, characterized in that, The second stone layer (10) is filled in the closed channel area (7) after dredging, and low-energy level dynamic compaction process treatment is carried out.
4. The soft ground improvement composite structure for riprap sea filling transition section according to claim 1, characterized in that, The third stone layer (11) is filled in the channel extension area (6) after dredging and forming of a dredging bottom boundary, and variable-length high-pressure rotary jet grouting pile treatment is carried out.
5. The riprap sea filling transition section's soft ground improvement composite structure according to claim 1, characterized in that, The fourth stone layer (12) is directly filled in the straight filling area (5), and the foundation is reinforced by using vibro-replacement stone column.
6. The soft ground improvement composite structure for riprap sea filling transition section according to claim 1, wherein The fifth stone layer (13) is directly filled in the left cofferdam extension area (4), and high-pressure rotary jet grouting pile treatment is carried out.
7. The riprap sea filling transition section's soft ground improvement combined structure according to claim 1, characterized by, The sixth stone layer (14) is filled in the cofferdam area (1) after dredging and extrusion by blasting, and low-energy level dynamic compaction process treatment is carried out.
8. The soft ground improvement composite structure for riprap sea filling transition section according to claim 1, characterized in that, The silt receiving area (2) is formed by hydraulic fill silt, and is reinforced by vacuum preloading combined with super-high load.
9. The soft ground improvement composite structure for riprap sea filling transition section according to claim 1, wherein The seventh stone layer (15) is directly filled in the right cofferdam extension area (3), and the foundation is reinforced by using vibro-replacement stone column.
10. The soft ground improvement composite structure for riprap sea filling transition section according to claim 1, characterized in that, During the service period of the dredging and replacement area (8), a small average settlement S1 occurs; during the service period of the closed channel area (7), a slight average settlement S2 occurs; during the service period of the channel extension area (6), a light average settlement S3 occurs; during the service period of the straight filling area (5), a moderate average settlement S4 occurs; during the service period of the left cofferdam extension area (4), a light average settlement S5 occurs; during the service period of the cofferdam area (1), a slight average settlement S6 occurs; during the service period of the right cofferdam extension area (3), a moderate average settlement S7 occurs; and during the service period of the silt receiving area (2), a significant average settlement S8 occurs. Settlement of each ground treatment partition ΔPi is the average additional stress of the ith layer of soil, MPa; Esi is the compression modulus of the ith layer of soil, MPa; hi is the thickness of the ith layer of soil; Meanwhile, the average differential settlement value between adjacent areas satisfies the following requirement: |Sk-Sk+1| / Delta H<5‰, wherein k is the partition number, is an integer of 1-7, Delta H is the midpoint horizontal distance between the K area and the k+1 area, and Sk is the partition settlement.