A large bay area soft soil foundation drainage ditch anti-settlement structure

Abstract

The utility model relates to the technical field of civil engineering drainage facilities, concretely relates to a big bay area soft soil foundation drainage canal anti -settlement structure, including a plurality of cement soil mixing piles, the bottom end of cement soil mixing pile is inserted into the underlying hard soil layer through the soft soil layer, the top of a plurality of cement soil mixing piles is provided with macadam mattress layer, the top of macadam mattress layer is provided with geogrid reinforced layer, a plurality of canal bodies that mutually splice are arranged on geogrid reinforced layer, canal body's inside is provided with canal section reinforcing rib, the bottom of canal body is provided with high anti -arch, the flexible joint is arranged between adjacent two canal bodies, and the water-swelling rubber waterstop is embedded in the flexible joint. The utility model has the advantages of firm structure, anti -settlement, and is favorable for prolonging the life.

Description

Technical Field

[0001] This utility model relates to the field of civil engineering drainage facilities technology, specifically to an anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area. Background Technology

[0002] Located in the Pearl River Delta alluvial plain, the Greater Bay Area has a wide distribution of soft soil foundations. These foundations are characterized by high water content, large porosity, low bearing capacity, and high compressibility. In the construction of infrastructure such as drainage ditches, uneven settlement of the foundation can easily lead to cracking, leakage, and collapse of the ditches. This not only affects the normal functioning of drainage but may also trigger a chain of engineering accidents such as the collapse of surrounding roads and damage to underground pipe networks. As a core facility for regional flood control, drainage, and ecological water replenishment, the structural stability of drainage ditches is directly related to the safety of urban operations and the protection of residents' lives.

[0003] Existing foundation treatment schemes for drainage ditches on soft soil foundations have some shortcomings: First, most adopt the replacement layer method (such as replacing with crushed stone or gravel), which only treats the surface soft soil and does not reach the deep soft soil layer. The high compressibility of the deep soft soil layer leads to long-term foundation settlement of 10-30cm, far exceeding the allowable settlement value of the ditches, eventually causing the ditches to crack. Second, some use single pile foundations for reinforcement, but the pile foundations are scattered and lack coordinated load-bearing design with the subgrade. Stress concentration at the top of the pile foundations can easily lead to damage to the subgrade. At the same time, the uneven settlement characteristics of soft soil foundations are not considered, and the deformation of the pile foundations and the foundation is not coordinated, which exacerbates the local stress cracking of the ditches.

[0004] On the other hand, some channels lack reinforcing bars or only have a small amount of steel reinforcement on the surface, resulting in insufficient tensile strength. Furthermore, the bottoms of many channels are flat, failing to disperse the vertical stress caused by foundation settlement, further reducing the channel's crack resistance. Therefore, we propose a settlement-resistant structure for drainage channels on soft soil foundations in the Greater Bay Area. Utility Model Content

[0005] The purpose of this utility model is to provide a settlement-resistant structure for drainage ditches on soft soil foundations in the Greater Bay Area, so as to solve the defects mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A settlement-resistant structure for drainage channels on soft soil foundations in the Greater Bay Area includes multiple cement-soil mixing piles. The bottom ends of the cement-soil mixing piles penetrate the soft soil layer and insert into the underlying hard soil layer. A crushed stone cushion layer is provided on top of the multiple cement-soil mixing piles. A geogrid reinforcement layer is provided on top of the crushed stone cushion layer. Multiple interconnected channel bodies are provided on the geogrid reinforcement layer. Channel section reinforcement bars are provided inside the channel bodies. A high inverted arch is provided at the bottom of the channel bodies. A flexible joint is provided between two adjacent channel bodies. A water-swellable rubber waterstop is embedded in the flexible joint.

[0007] Preferably, the plurality of cement-soil mixing piles are arranged in an equilateral triangle shape, with a pile spacing of 1.2 to 1.5 m; This feature helps to improve the bearing capacity of the composite foundation and reduce the occurrence of collapse.

[0008] Preferably, a composite geomembrane cushion layer is provided between the geogrid reinforcement layer and the channel body, and the thickness of the composite geomembrane cushion layer is between 3mm and 5mm. This feature provides protection against seepage and prevents collapse caused by infiltration.

[0009] Preferably, a cement-based penetrating crystalline waterproof coating layer is provided on the inner surface of the channel body, and an asphalt-based waterproof coating layer is provided on the outer surface of the channel body; This feature protects the canal body and helps extend its service life.

[0010] Preferably, the thickness of the cement-based penetrating crystalline waterproof coating layer is between 1 mm and 2.5 mm, and the thickness of the bitumen-based waterproof coating layer is between 2 mm and 3.5 mm.

[0011] Preferably, a medium-coarse sand paving layer is provided between the two sides of the channel body and the foundation, and bagged sand wells are provided between the two sides of the medium-coarse sand paving layer and the foundation. This feature reduces lateral earth pressure, making the canal structure more robust and stable.

[0012] Preferably, the flexible joint is further provided with a polyurethane sealant layer and a water-swellable putty strip, wherein the polyurethane sealant layer is located on the outside of the water-swellable rubber waterstop and the water-swellable putty strip is located on the inside of the water-swellable rubber waterstop. This setting enables a sealing operation between two adjacent channels, ensuring a tight seal and preventing leakage.

[0013] Preferably, the flexible joint is further provided with a stainless steel edging, which is installed on the outer side of two adjacent channel bodies; This feature makes the connection between two adjacent channels more secure.

[0014] Compared with the prior art, the beneficial effects of this utility model are: 1. This utility model replaces the traditional method of replacing only the surface soft soil or the scattered pile foundation by setting up multiple cement-soil mixing piles with their bottom ends penetrating through the soft soil layer and inserting into the underlying hard soil layer. The cement-soil mixing piles penetrate deep into the hard soil layer to form a deep reinforcement system. Combined with the equilateral triangular arrangement, it enhances the bearing capacity of the composite foundation, effectively constrains the compression deformation of the deep soft soil, keeps the long-term settlement of the foundation within the allowable range, avoids the cracking of the channel body caused by foundation settlement, and achieves the effect of enhancing the stability of the foundation and reducing the risk of collapse.

[0015] 2. This utility model solves the problem of poor crack resistance of traditional flat-bottomed canals by setting up internal canal section reinforcing ribs, a high arch at the bottom, and a cement-based penetrating crystalline waterproof coating layer on the inner surface of the canal and an asphalt-based waterproof coating layer on the outer surface. The canal section reinforcing ribs improve the tensile strength of the canal, and the high arch disperses the vertical stress generated by foundation settlement. The double-layer waterproof coating provides all-round protection for the canal, preventing water erosion from causing structural damage, thereby improving the crack resistance of the canal and extending its service life.

[0016] 3. This utility model, by setting up flexible joints between adjacent channels, embedding water-swellable rubber waterstops, an outer polyurethane sealant layer, an inner water-swellable putty strip, an outer stainless steel edging, a composite geomembrane cushion layer between the geogrid reinforcement layer and the channel body, a medium-coarse sand paving layer on both sides of the channel body, and bagged sand wells, the flexible joints adapt to uneven foundation settlement, the multiple water-stopping structures block leakage, the composite geomembrane cushion layer prevents seepage, and the medium-coarse sand and bagged sand wells reduce lateral earth pressure, forming a "seepage prevention-buffering-lateral pressure resistance" synergistic system, achieving the effect of avoiding joint cracking and leakage and enhancing the overall stability of the channel body. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is one of the partial structural schematic diagrams of this utility model; Figure 3 This is the second partial structural schematic diagram of the present utility model; Figure 4 This utility model Figure 3 Enlarged view of point A in the middle; The meanings of the labels in the diagram are as follows: 10. Soft soil layer; 11. Cement-soil mixing pile; 12. Crushed stone cushion layer; 13. Geogrid reinforcement layer; 14. Composite geomembrane cushion layer; 2. Channel body; 20. Channel section reinforcing bars; 21. Cement-based penetrating crystalline waterproof coating layer; 22. Asphalt-based waterproof coating layer; 23. High arch; 24. Medium-coarse sand paving layer; 25. Bagged sand well; 3. Flexible joints; 30. Stainless steel edging; 31. Polyurethane sealant layer; 32. Water-swellable rubber waterstop; 33. Water-swellable putty strip. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figures 1-4 This utility model provides a technical solution: a settlement-resistant structure for drainage ditches on soft soil foundations in the Greater Bay Area, comprising multiple cement-soil mixing piles 11. The bottom end of the cement-soil mixing piles 11 penetrates the soft soil layer 10 and inserts into the underlying hard soil layer 1. The cement-soil mixing piles 11 can penetrate deep into the soft soil foundation, transferring the load to the underlying hard soil layer 1 with stronger bearing capacity, avoiding the problem of deep settlement caused by only treating the surface soft soil, and providing stable foundation support for the entire drainage ditch structure.

[0020] like Figure 1 As shown, a crushed stone cushion layer 12 is provided on the top of multiple cement-soil mixing piles 11. The crushed stone cushion layer 12 can buffer the stress concentration at the top of the cement-soil mixing piles 11, avoid the direct force on the top of the pile body causing damage to the cushion layer, and at the same time adjust the distribution of the foundation reaction force, so that the load is evenly transferred to the pile body and the foundation, reducing uneven settlement.

[0021] like Figure 1 As shown, a geogrid reinforcement layer 13 is provided on the top of the crushed stone cushion layer 12. The crushed stone cushion layer 12 is filled in the mesh of the geogrid reinforcement layer 13. The geogrid reinforcement layer 13 can enhance the integrity of the cushion layer, restrain the lateral extrusion of crushed stone, improve the deformation resistance of the cushion layer, and at the same time disperse the load transmitted by the upper channel 2, further reducing the risk of uneven settlement of the foundation.

[0022] In this embodiment, multiple interconnected channel bodies 2 are provided on the geogrid reinforcement layer 13. The splicing design facilitates flexible assembly according to the length of the drainage channel. Compared with the integral cast-in-place channel body, it is more adaptable to minor foundation settlement and reduces the overall cracking of the channel body caused by settlement differences. Channel body 2 is provided with channel segment reinforcing bars 20 inside. Channel segment reinforcing bars 20 can enhance the tensile strength and overall stiffness of channel body 2, prevent channel body 2 from cracking due to tensile force generated by foundation settlement, and improve the deformation resistance of channel body 2. The bottom of channel body 2 is provided with a high anti-arch 23. The high anti-arch 23 structure can disperse the vertical stress generated by foundation settlement to both sides, avoid stress concentration at the bottom center of channel body 2, solve the problem of poor crack resistance of traditional flat bottom slab channel bodies, and protect the structural integrity of channel body 2.

[0023] Specifically, a flexible joint 3 is provided between two adjacent channel bodies 2. The flexible joint 3 is embedded with a water-swellable rubber waterstop 32. The flexible joint 3 can adapt to the small displacement caused by uneven settlement of the foundation of the adjacent channel body 2. If the displacement is less than 5mm, the water-swellable rubber waterstop 32 will expand after contacting the water and fill the gap of the joint to prevent water leakage.

[0024] Furthermore, multiple cement-soil mixing piles 11 are arranged in an equilateral triangle shape with a pile spacing of 1.2 to 1.5 meters. The equilateral triangle arrangement can evenly distribute the force on the pile body, which can more efficiently improve the overall bearing capacity of the composite foundation compared with other arrangements, reduce the occurrence of local foundation collapse, and further enhance the stability of the foundation.

[0025] like Figure 1 As shown, a composite geomembrane cushion layer 14 is provided between the geogrid reinforcement layer 13 and the channel body 2. The thickness of the composite geomembrane cushion layer 14 is between 3mm and 5mm. The composite geomembrane cushion layer 14 can block the water in the channel body 2 from seeping into the foundation, avoid the seepage water from softening the soft soil layer 10, which would lead to a decrease in the bearing capacity of the foundation and cause collapse, and play a reliable anti-seepage protection role.

[0026] In addition, a cement-based penetrating crystalline waterproof coating layer 21 is provided on the inner surface of the channel body 2, and an asphalt-based waterproof coating layer 22 is provided on the outer surface of the channel body 2. The thickness of the cement-based penetrating crystalline waterproof coating layer 21 is between 1 mm and 2.5 mm, and the thickness of the asphalt-based waterproof coating layer 22 is between 2 mm and 3.5 mm. The double-layer waterproof coating can protect the channel body 2 from both the inside and outside. The cement-based coating blocks the penetration of internal water, and the asphalt-based coating resists the erosion of external groundwater, thus preventing the channel body 2 from being damaged by water erosion and extending its service life.

[0027] like Figure 2As shown, a medium-coarse sand paving layer 24 is provided between the two sides of the channel body 2 and the foundation. Bag-filled sand wells 25 are provided between the two sides of the medium-coarse sand paving layer 24 and the foundation. The medium-coarse sand paving layer 24 can buffer the lateral earth pressure of the foundation on the channel body 2. The bag-filled sand wells 25 can accelerate the drainage and consolidation of the soft soil layer 10, reduce the lateral deformation of the foundation, and make the structure of the channel body 2 more solid and stable.

[0028] like Figure 3 and Figure 4 As shown, the flexible joint 3 is also provided with a polyurethane sealant layer 31 and a water-swellable putty strip 33. The polyurethane sealant layer 31 is located on the outside of the water-swellable rubber waterstop 32, and the water-swellable putty strip 33 is located on the inside of the water-swellable rubber waterstop 32. The polyurethane sealant layer 31 can seal the joint from the outside, and the water-swellable putty strip 33 assists in water stop from the inside. Together with the water-swellable rubber waterstop 32, they form a triple sealing system to further ensure the sealing effect and prevent leakage.

[0029] In addition, the flexible joint 3 is also equipped with a stainless steel edging 30. The stainless steel edging 30 is installed on the outer side of the two adjacent channel bodies 2 by multiple fastening bolts. The stainless steel edging 30 can reinforce the connection of the adjacent channel bodies 2 from the outside, enhance the integrity of the joint, make the connection between the two channel bodies 2 tighter, and prevent the joint from being misaligned due to external force or settlement.

[0030] It is worth noting that the cement content of the cement-soil mixing pile 11 is 15%-20%, the single pile bearing capacity is ≥200kN, and the bearing capacity of the composite foundation is increased to 150-200kPa, controlling deep settlement; the crushed stone cushion layer 12 can use graded crushed stone with a particle size of 5-30mm, which is rolled in layers with a compaction degree of ≥96% to form a flexible transition layer, disperse the upper load, and eliminate the differential settlement between pile and soil; the geogrid reinforcement layer 13 can use bidirectional polypropylene geogrid 104 with a tensile strength of ≥200kN / m, an elongation of ≤10%, and a geogrid overlap length of ≥200mm and tied connection to enhance the integrity of the foundation and suppress lateral deformation.

[0031] It is worth noting that the channel body 2 can be precast using C40 self-stressing concrete to improve its strength; the composite geomembrane cushion layer 14 can adopt a two-layer fabric-one-membrane structure, with the non-woven fabric weight ≥200g / m². 2 HDPE membrane thickness 1.5mm, permeability coefficient ≤1×10⁻ 10 cm / s, membrane overlap width ≥100mm and hot-melt welded, welding strength ≥80% of the parent material, covering the bottom of the channel and the slopes on both sides, extending 500mm above the top of the channel, blocking the leakage path of the channel body 2.

[0032] The application process of this utility model's anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area is as follows: Foundation construction: Cement-soil mixing piles 11 are driven in an equilateral triangle arrangement with a pile spacing of 1.2-1.5m, so that the bottom end penetrates the soft soil layer 10 and inserts into the underlying hard soil layer 1. The top is covered with a crushed stone cushion layer 12 and compacted, and then a geogrid reinforcement layer 13 is laid, with crushed stone filling the geogrid mesh. Seepage prevention laying: Lay a 3-5mm thick composite geomembrane pad 14 on the geogrid reinforcement layer 13 to ensure full coverage of the channel installation area; Channel assembly: The channel body 2 with channel section reinforcing ribs 20 and high arch 23 is spliced ​​together. The inner side is coated with a 1-2.5mm cement-based penetrating crystalline waterproof coating layer 21, and the outer side is coated with a 2-3.5mm asphalt-based waterproof coating layer 22. At the flexible joint 3, water-swellable putty strips 33 and water-swellable rubber waterstops 32 are installed in sequence. The outer side is coated with a polyurethane sealant layer 31 and fixed with stainless steel edging 30 and fastening bolts. Backfilling and reinforcement: Medium and coarse sand paving layers 24 are backfilled on both sides of the channel body 2, and bagged sand wells 25 are set on the outside to accelerate the drainage and consolidation of soft soil, complete the installation of anti-settlement structure, and put it into drainage use.

[0033] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A settlement-resistant structure for drainage ditches on soft soil foundations in the Greater Bay Area, comprising multiple cement-soil mixing piles (11), characterized in that: The bottom end of the cement-soil mixing pile (11) passes through the soft soil layer (10) and inserts into the underlying hard soil layer (1). A crushed stone cushion layer (12) is provided on the top of the multiple cement-soil mixing piles (11). A geogrid reinforcement layer (13) is provided on the top of the crushed stone cushion layer (12). Multiple interconnected channel bodies (2) are provided on the geogrid reinforcement layer (13). Channel section reinforcing bars (20) are provided inside the channel body (2). A high reverse arch (23) is provided at the bottom of the channel body (2). A flexible joint (3) is provided between two adjacent channel bodies (2). A water-swellable rubber waterstop (32) is embedded in the flexible joint (3).

2. The anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area according to claim 1, characterized in that: Multiple cement-soil mixing piles (11) are arranged in an equilateral triangle shape with a pile spacing of 1.2 to 1.5 m.

3. The anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area according to claim 1, characterized in that: A composite geomembrane cushion layer (14) is provided between the geogrid reinforcement layer (13) and the channel body (2), and the thickness of the composite geomembrane cushion layer (14) is between 3mm and 5mm.

4. The anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area according to claim 1, characterized in that: The inner surface of the channel body (2) is provided with a cement-based penetrating crystalline waterproof coating layer (21), and the outer surface of the channel body (2) is provided with an asphalt-based waterproof coating layer (22).

5. The anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area according to claim 4, characterized in that: The thickness of the cement-based penetrating crystalline waterproof coating layer (21) is between 1 mm and 2.5 mm, and the thickness of the bitumen-based waterproof coating layer (22) is between 2 mm and 3.5 mm.

6. The anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area according to claim 1, characterized in that: A medium-coarse sand paving layer (24) is provided between the two sides of the channel body (2) and the foundation, and bagged sand wells (25) are provided between the two sides of the medium-coarse sand paving layer (24) and the foundation.

7. The anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area according to claim 1, characterized in that: The flexible joint (3) is also provided with a polyurethane sealant layer (31) and a water-swellable putty strip (33). The polyurethane sealant layer (31) is located on the outside of the water-swellable rubber waterstop (32), and the water-swellable putty strip (33) is located on the inside of the water-swellable rubber waterstop (32).

8. The anti-settlement structure for drainage ditches on soft soil foundations in the Greater Bay Area according to claim 1, characterized in that: The flexible joint (3) is also provided with a stainless steel edging (30), which is installed on the outer side of two adjacent channels (2).

Images