Green embankment structure for soft soil foundation in limited space and construction method thereof

Abstract

This invention discloses a green embankment structure and its construction method for confined space marine soft soil foundations, belonging to the technical field of water conservancy and coastal engineering. The structure includes a silt layer, a silt layer, a drainage board assembly structure, a drainage sand cushion layer, ballast bagged sand, pile foundations, protective bagged sand for the pile foundations, bagged sand sheets, a novel bagged sand sheet embankment, and dredged silt. The drainage sand cushion layer is placed above the silt layer; the drainage board assembly structure penetrates the drainage sand cushion layer and inserts into the silt layer; the pile foundations are wrapped with protective bagged sand for resisting horizontal deformation; the bagged sand sheets are interconnected to form a novel bagged sand sheet embankment to block the horizontal thrust generated by the dredged silt. This invention solves the problems of low bearing capacity and large horizontal deformation in confined space soft soil foundations, and has the advantages of being green and environmentally friendly and convenient to construct.

Description

Technical Field

[0001] This invention relates to the fields of water conservancy and coastal engineering technology, and in particular to a green embankment structure for marine soft soil foundation in a confined space and its construction method. Background Technology

[0002] Soft soil foundations typically exhibit characteristics such as high water content, low strength, high compressibility, and poor permeability. Improper treatment can easily lead to significant settlement and poor stability of the dike body, even affecting the safety of the superstructure. In offshore dike construction projects on soft soil foundations, especially in confined spaces such as under bridges or in areas with dense pipelines, effectively managing the weak silt layer while ensuring structural stability is a pressing issue that needs to be addressed.

[0003] Currently, relevant patents exist in the prior art. For example, Chinese invention patent application CN105804007A (publication date: July 27, 2016) discloses a reinforced soil revetment structure suitable for soft soil foundations in tidal flat areas. This structure includes plastic drainage boards embedded in the soft soil, a drainage cushion layer laid on the soft soil surface, a sand-filled cofferdam, prefabricated wall panels for protection and retaining, reinforcing strips pre-embedded in the sand-filled cofferdam, filling material between the wall panels and the sand-filled cofferdam, pile foundations below the panels, cap stones above the panels, and geotextile filter fabric behind the sand-filled cofferdam. By implementing this structure in stages, the deformation of the soft soil foundation and cofferdam is essentially completed before the construction of the wall panels, reducing post-construction settlement and uneven settlement. The sand-filled cofferdam can also serve as a construction platform for the wall panels and pile foundations, transforming intertidal zone construction into onshore construction and improving construction conditions. The structure can adapt to the bearing capacity and deformation of soft soil foundations, has a simple construction process, can be constructed in stages, and saves investment. However, the structure does not have protective measures for the pile foundation itself to resist horizontal deformation, and the structure is mainly suitable for tidal flat area bank projects, and is not suitable for dike construction in limited spaces such as under bridges.

[0004] For example, Chinese utility model patent CN206438495U (publication date: August 25, 2017) discloses a self-draining, post-consolidation, sandbag-filled composite pile system and its construction method. The self-draining, post-consolidation, sandbag-filled composite pile system is characterized by: sandbag wells, plastic drainage boards, or post-consolidation loose piles set in the soft soil foundation to form vertical drainage channels; and a post-consolidation, sandbag layer set above the sandbag wells, plastic drainage boards, or post-consolidation loose piles. This utility model offers rapid drainage consolidation, high post-consolidation strength, high bearing capacity, and good overall stability, and can be applied to the treatment of soft soil foundations with various water contents. However, while this solution can achieve drainage consolidation of soft foundations, it mainly addresses insufficient foundation bearing capacity and post-construction settlement problems, without addressing technical measures to resist horizontal deformation when the pile foundation penetrates soft soil layers, and lacks effective means to resist the horizontal thrust generated by dredged silt.

[0005] In summary, existing soft soil foundation embankment structures primarily focus on addressing foundation bearing capacity and settlement issues, lacking effective measures to resist the horizontal thrust generated by dredged silt, especially when pile foundations penetrate soft soil layers, failing to fully consider the impact of horizontal deformation on shear forces and bending moments. Therefore, this application provides a green embankment structure for marine soft soil foundations within confined spaces, solving the problems of low bearing capacity, large horizontal deformation, and poor adaptability to construction in confined spaces. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application provides a green dike construction structure for marine soft soil foundations in a limited space, comprising: The silt and silt layers are located at the bottom; A drainage sand cushion layer is disposed above the silt layer; The drainage board assembly structure penetrates the drainage sand cushion layer and is inserted into the silt layer; Ballast bagged sand is placed on top of the drainage board assembly structure; The pile foundation penetrates the drainage sand cushion layer and the silt layer and is inserted into the silt layer; Protective sandbags are placed around the outer perimeter of the piles to resist horizontal deformation. A bagged sand blanket is used to cover the top of the ballast bagged sand. The bagged sand sheets are interconnected to form a new type of bagged sand sheet embankment, which is used to block the horizontal thrust generated by the dredged silt on the outside.

[0007] Furthermore, the silt layer serves as the bearing layer of the novel bagged sand embankment.

[0008] Furthermore, the lower end of the pile foundation is embedded in the silty soil layer, and the embedding depth is determined according to the design bearing capacity.

[0009] Furthermore, the drainage board assembly structure is pressed into the drainage sand cushion layer and silt layer by the pressure of the ballast bagged sand, thus establishing a vertical drainage channel.

[0010] Furthermore, the number of drainage board assembly structures is determined based on the length of the gently sloping area at the bottom of the silt layer.

[0011] Furthermore, the protective sandbags are wrapped around the portion of the pile foundation that passes through the silt layer, enabling it to adapt to local horizontal deformation.

[0012] Furthermore, the bagged sand is located on the upper part and both sides of the bagged sand of the protective pile foundation.

[0013] Furthermore, the bagged sand is formed using a blowdown process to load and consolidate the lower silt layer.

[0014] This application also provides a construction method for green dike structures on marine soft soil foundations in confined spaces, including the following steps: Step S1: Lay a drainage sand cushion layer on top of the silt layer to be reinforced; Step S2: Install a drainage board assembly structure on the drainage sand cushion layer, and press the drainage board assembly structure into the drainage sand cushion layer and the silt layer below by ballast bagged sand. Step S3: Construct pile foundations, allowing them to penetrate the silt layer and be driven into the silty soil layer; Step S4: Set up protective sandbags around the pile foundation; Step S5: Inject bagged sand into the drainage sand cushion layer and the ballast bagged sand to form a bagged sand blanket, and connect the bagged sand blankets to form a new type of bagged sand blanket embankment with an integral structure. Step S6: Dredging and filling silt construction, the new type of bagged sand embankment is used to block the horizontal thrust generated by dredged and filled silt.

[0015] Furthermore, in step S2, the drainage board assembly structure is arranged at a preset spacing and pressed into the silt layer to a designed depth by ballast bagged sand.

[0016] Furthermore, in step S5, the bagged sand is stacked in layers. After each layer is stacked, it is left to stand for a preset time until the silt layer is drained, consolidated, and settled and stabilized before the next layer is stacked.

[0017] Compared with existing technologies, the advantages and effects of this application are as follows: 1. Although existing technologies use bagged sand wells or plastic drainage boards in conjunction with upper sandbag filling layers for surcharge consolidation, the consolidation efficiency is not high. This application uses ballast bagged sand to press the drainage board combination structure into the drainage sand cushion layer and silt layer, establishing an efficient vertical drainage channel. Combined with the surcharge preloading effect of the upper bagged sand, it achieves rapid drainage consolidation of the silt layer, improves the bearing capacity of the soft foundation, and solves the problem of low bearing capacity of the intermediate soft silt layer.

[0018] 2. Most existing technologies do not consider protective measures against horizontal deformation when pile foundations penetrate soft soil layers. This application, by setting up protective pile foundation bags filled with sand, effectively absorbs and adapts to local horizontal deformation, isolates the horizontal thrust generated by the dredged silt, and significantly reduces the horizontal shear force and bending moment on the pile foundation, thus ensuring the safety and stability of the high pile beam-slab structure.

[0019] 3. This application is particularly applicable to embankment construction projects on soft soil foundations with limited space, such as under utility tunnels and in densely populated areas with pipelines. It makes full use of in-situ silt and dredged silt, avoiding large-scale mountain excavation and off-site disposal, and has the advantages of being green, environmentally friendly, economical and cost-effective.

[0020] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0021] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0023] in: Figure 1 A schematic diagram of the overall structure of a green embankment structure for marine soft soil foundation in a limited space; Figure 2 This is a schematic diagram of the combined structure of ballast bagged sand and drainage board; Figure 3 This is a magnified view of the pile foundation and the sand-filled protective pile foundation. Figure 4 This is a construction flowchart for a green embankment structure for use in confined spaces on soft soil foundations at sea.

[0024] Explanation of reference numerals in the attached figures: 1-Silt layer; 2-Silty soil layer; 3-Drainage board combination structure; 4-Drainage sand cushion layer; 5-Battery bagged sand; 6-Pile foundation; 7-Protective pile foundation bagged sand; 8-Bagged sand cover; 9-New type of bagged sand cover embankment; 10-Dragging silt. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0026] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0027] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0028] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it have an "or" relationship.

[0029] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0030] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0031] Example 1 This embodiment introduces a green dike construction structure for marine soft soil foundations in a limited space. Please refer to the appendix. Figure 1-3 , Figure 1 A schematic diagram of the overall structure of a green embankment structure for marine soft soil foundation in a limited space; Figure 2 This is a schematic diagram of the combined structure of ballast bagged sand and drainage board; Figure 3 This is a magnified view of the pile foundation and the sand-filled protective pile foundation. The structure includes: Silt layer 1 and silt layer 2 are located at the bottom; A drainage sand cushion layer 4 is disposed above the silt layer 1; The drainage board assembly structure 3 penetrates the drainage sand cushion layer 4 and is inserted into the silt layer 1; Ballast bagged sand 5 is ballasted on top of the drainage board assembly structure 3; The pile foundation 6 penetrates the drainage sand cushion layer 4 and the silt layer 1 and is inserted into the silt layer 2; Protective sandbags 7 are wrapped around the outer periphery of the pile foundation 6 to resist horizontal deformation; A bagged sand blanket 8 covers the upper part of the ballast bagged sand 5; The bagged sand sheets 8 are interconnected to form a new type of bagged sand sheet embankment 9, which is used to block the horizontal thrust generated by the external dredged silt 10.

[0032] Furthermore, the silt layer 2 serves as the bearing layer of the novel bagged sand embankment 9.

[0033] Furthermore, the lower end of the pile foundation 6 is embedded in the silty soil layer 2, and the embedding depth is determined according to the design bearing capacity.

[0034] Furthermore, the drainage board assembly structure 3 is pressed into the drainage sand cushion layer 4 and the silt layer 1 by the pressure of the ballast bag sand 5, thus establishing a vertical drainage channel.

[0035] Furthermore, the number of drainage board assembly structures 3 is determined based on the length of the gently sloping area at the bottom of the silt layer 1.

[0036] Furthermore, the protective pile foundation bagged sand 7 is wrapped around the portion of the pile foundation 6 that passes through the silt layer 1, so that it can adapt to local horizontal deformation.

[0037] Furthermore, the bagged sand 8 is located on the upper part and both sides of the bagged sand 7 protecting the pile foundation.

[0038] Furthermore, the bagged sand 8 is formed using a blow-drying process and is used to load and consolidate the lower silt layer 1.

[0039] The technical effects of this embodiment are as follows: This embodiment achieves rapid drainage and consolidation of the silt layer through the combined structure of drainage boards, the synergistic effect of ballast bagged sand and bagged sand sheets, and effectively isolates horizontal thrust by combining the bagged sand of the protective pile foundation. While solving the problems of low bearing capacity and large horizontal deformation of soft foundation in limited space, it also achieves green and environmentally friendly construction.

[0040] Example 2 Based on Example 1, a construction method for green dike structures on confined marine soft soil foundations is introduced. Please refer to the appendix. Figure 4 , Figure 4 A construction flowchart for a green embankment structure for confined space offshore soft soil foundations; Includes the following steps: Step S1: Lay a drainage sand cushion layer 4 on top of the silt layer 1 to be reinforced; Step S2: Install a drainage board assembly structure 3 on the drainage sand cushion layer 4, and press the drainage board assembly structure 3 into the drainage sand cushion layer 4 and the silt layer 1 below it by ballast bagged sand 5. Step S3: Construct pile foundation 6, allowing it to penetrate the silt layer 1 and be driven into the silty soil layer 2; Step S4: Set up protective sandbags 7 around the pile foundation 6; Step S5: Inject bagged sand into the upper part of the drainage sand cushion layer 4 and the ballast bagged sand 5 to form bagged sand blanket 8, and connect the bagged sand blankets 8 to form a new type of bagged sand blanket embankment 9 with an integral structure. Step S6: Construction of dredged silt 10, wherein the new type of bagged sand embankment 9 is used to block the horizontal thrust generated by dredged silt 10.

[0041] Furthermore, in step S2, the drainage board assembly structure 3 is arranged at a preset spacing and pressed into the silt layer 1 to the designed depth by ballast bagged sand 5.

[0042] Furthermore, in step S5, the bagged sand 8 is stacked in layers. After each layer is stacked, it is left to stand for a preset time until the silt layer 1 is drained, consolidated, and settled and stabilized before the next layer is stacked.

[0043] Example 3 Based on Examples 1 and 2, this example introduces a construction method for a green embankment structure for marine soft soil foundation in a confined space under specific application scenarios.

[0044] This embodiment takes a dam construction project in a confined space under a utility tunnel bridge as an example. The utility tunnel bridge is 13m wide, 100m long, and has a clearance height of 3m.

[0045] The foundation soil layers, from top to bottom, consist of a 3m thick silt layer 1 and a 5m thick silt layer 2.

[0046] Step S1: Lay a drainage sand cushion layer 4 with a thickness of 0.5m on top of the silt layer 1; Step S2: Install a drainage board assembly structure 3 with dimensions of 3m high × 1m wide × 1m long on the drainage sand cushion layer 4, and use geotextile bags with a diameter of 1.0m, a length of 1.5m and a sand filling rate of 80% to press the bagged sand 5 into the drainage sand cushion layer 4 and the silt layer 1 to establish a vertical drainage channel for the silt layer 1. Step S3: Then construct a pile foundation 6 with a diameter of 1.2m, so that it penetrates the silt layer 1 and is driven into the silt layer 2 as the bearing layer; Step S4: Wrap the pile foundation 6 with a geotextile bag with a diameter of 1.0m, a length of 1.5m, and a sand filling rate of 80% at the part where the pile foundation 6 passes through the silt layer 1 to protect the pile foundation bag sand 7, which is used to absorb local horizontal deformation and reduce the bending moment and shear force of the pile body. Step S5: A bagged sand blanket 8 with a length of 5m~10m, a width of 10m~30m, and a thickness of 0.5m~0.8m is formed by shoveling sand into the upper part of the ballast bagged sand 5 and the drainage sand cushion layer 4. Multiple bagged sand blankets 8 are connected to each other to form a new type of bagged sand blanket embankment 9 with a bottom width of 60m, a top width of 6m, and a height of 12m. Step S6: Hydraulically fill a 10m thick layer of silt.

[0047] Furthermore, the new type of bagged sand embankment 9 effectively blocks the horizontal thrust generated by the subsequent 10m thick dredged silt 10, while the surcharge effect of the upper bagged sand embankment 8 accelerates the drainage and consolidation of the lower silt layer 1, thereby improving the bearing capacity of the foundation.

[0048] The technical effects of this embodiment are as follows: In the limited space under the pipe gallery bridge, this embodiment achieves rapid drainage and consolidation of the silt layer through the synergistic effect of the drainage board combination structure, ballast bagged sand, and bagged sand blanket. The drainage board combination structure and the silt layer form a composite foundation similar to short piles. The bagged sand blanket is used to protect the pile foundation, enabling it to adapt to local horizontal deformation. The bagged sand blanket is buried to form a new type of bagged sand blanket embankment, which reduces the horizontal shear force and bending moment on the pile foundation and ensures the safety of the high pile beam-slab structure.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, and parameter adjustments made to this embodiment within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A green embankment structure for offshore soft soil foundation in limited space, characterized in that, include: The silt layer (1) and the silt layer (2) are located at the bottom; A drainage sand cushion layer (4) is disposed above the silt layer (1); The drainage board assembly structure (3) penetrates the drainage sand cushion layer (4) and is inserted into the silt layer (1); Ballast bagged sand (5) is placed on top of the drainage board assembly structure (3); The pile foundation (6) penetrates the drainage sand cushion layer (4) and the silt layer (1) and is inserted into the silt layer (2); Protective sandbags (7) are wrapped around the outer periphery of the pile foundation (6) to resist horizontal deformation; A bagged sand blanket (8) is placed over the ballast bagged sand (5); The bagged sand sheets (8) are interconnected to form a new type of bagged sand sheet embankment (9), which is used to block the horizontal thrust generated by the outer backfill silt (10).

2. The green embankment structure of soft soil foundation at sea in limited space according to claim 1, characterized in that, The silt layer (2) serves as the bearing layer of the new type of bagged sand embankment (9).

3. The green embankment structure of soft soil foundation at sea in limited space according to claim 1, characterized in that, The drainage board assembly structure (3) is pressed into the drainage sand cushion layer (4) and silt layer (1) by the pressure of the ballast bag sand (5), thus establishing a vertical drainage channel.

4. The green embankment structure of soft soil foundation at sea in limited space according to claim 3, characterized in that, The number of drainage board assembly structures (3) is determined according to the length of the flat area at the bottom of the silt layer (1).

5. The green embankment structure of soft soil foundation at sea in limited space according to claim 1, characterized in that, The protective pile foundation bagged sand (7) is wrapped around the part of the pile foundation (6) above the silt layer (1) so that it can adapt to local horizontal deformation.

6. The limited space offshore soft ground green embankment structure according to claim 5, wherein The bagged sand (8) is located on the top and sides of the bagged sand (7) of the protective pile foundation.

7. The green embankment structure of claim 6, wherein The bagged sand blanket (8) is formed by a blow-drying process and is used to load and consolidate the lower silt layer (1).

8. A method for constructing a green embankment structure on a soft soil foundation at sea in a limited space according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step S1: Lay a drainage sand cushion layer (4) on top of the silt layer (1) to be reinforced; Step S2: Install a drainage board assembly structure (3) on the drainage sand cushion layer (4), and press the drainage board assembly structure (3) into the drainage sand cushion layer (4) and the silt layer (1) below it by ballast bagged sand (5); Step S3: Construct pile foundation (6) to penetrate the silt layer (1) and drive it into the silt layer (2); Step S4: Set up protective pile foundation bagged sand (7) around the pile foundation (6); Step S5: Inject bagged sand into the upper part of the drainage sand cushion layer (4) and the ballast bagged sand (5) to form a bagged sand blanket (8), and connect the bagged sand blankets (8) to form a new type of bagged sand blanket embankment (9) with an integral structure. Step S6: Construction of dredged silt (10), wherein the new type of bagged sand embankment (9) is used to block the horizontal thrust generated by the dredged silt (10).

9. The construction method according to claim 8, characterized in that, In step S2, the drainage board assembly structure (3) is arranged at a preset spacing and pressed into the silt layer (1) to the designed depth by ballast bagged sand (5).

10. The construction method according to claim 8, characterized in that, In step S5, the bagged sand (8) is stacked in layers. After each layer is stacked, it is left to stand for a preset time until the silt layer (1) is drained, consolidated and settled and stabilized before the next layer is stacked.

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