Method for embankment construction on soft ground

Abstract

The application discloses a kind of embankment construction methods of soft ground, it is related to the technical field of road construction, comprising the following steps:S1.in the construction filter pile and extruded pile in foundation;S2.construction drainage pipeline;S3.in the construction drainage ditch on the both sides of embankment;S4.construction drainage pipe gallery on foundation;S5.lay filter layer above drainage pipe gallery;S6.lay embankment earthwork, and set up geogrid in embankment earthwork;S7.construction pavement.The application has the effect of reducing the influence of groundwater on embankment structure.

Description

Technical Field

[0001] This application relates to the technical field of road construction, and in particular to a method for constructing embankments on soft foundations. Background Technology

[0002] Soft foundations refer to foundations mainly composed of silt, silty soil, fill, miscellaneous fill, or other highly compressible soil layers. Such foundations have excessive natural water content and low bearing capacity, making them prone to sliding or consolidation settlement under load. An embankment, on the other hand, refers to a fill roadbed where the top surface is higher than the original ground level.

[0003] When constructing embankments on soft foundations, it is usually necessary to treat the soft foundation soil. Common treatment methods include replacement, preloading, compaction, deep mixing, high-pressure jet grouting, grouting, dynamic compaction, and reinforcement.

[0004] However, when road construction is carried out in areas with high water content and abundant groundwater, the embankment is prone to collapse due to the constant erosion of groundwater over the years after the road surface is completed. Summary of the Invention

[0005] To reduce the impact of groundwater on embankments, this application provides a method for constructing embankments on soft foundations.

[0006] This application provides a method for constructing embankments on soft foundations, employing the following technical solution:

[0007] A method for constructing an embankment on a soft foundation includes the following steps:

[0008] S1. Construct filter piles and compaction piles within the foundation;

[0009] S2. Construction drainage pipeline;

[0010] S3. Construct drainage ditches on both sides of the embankment;

[0011] S4. Construct a drainage pipe gallery on the foundation;

[0012] S5. Lay a filter layer above the drainage pipe gallery;

[0013] S6. Lay the embankment earthwork and install geogrids in the embankment earthwork;

[0014] S7. Construction road surface.

[0015] By adopting the above technical solutions, on the one hand, the bearing capacity of the foundation soil layer is improved under the compaction effect of compaction piles and filter piles, and on the other hand, the installation of filter piles can enable the groundwater in the foundation to be discharged quickly, reducing the impact of groundwater on the bearing capacity and stability of the road foundation.

[0016] The construction of drainage ditches allows groundwater within the filter piles to be drained into the drainage ditches through drainage pipes, thereby reducing the moisture content of the foundation soil.

[0017] The construction of drainage pipe corridors and the installation of filter layers above them allow water accumulation in the embankment to be discharged smoothly through the drainage pipe corridors, reducing the possibility of water accumulation in the embankment and causing the embankment structure to collapse or landslide.

[0018] Installing geogrids within the embankment restricts lateral displacement of the soil, reduces landslides and collapses, and makes the embankment structure more stable, thus extending the road's service life.

[0019] Optionally, the filter pile is a drainage sand pile, and the compaction pile is a lime pile.

[0020] By adopting the above technical solutions, both filter piles and compaction piles can compact the foundation soil, thus improving the bearing capacity of the foundation. The filter piles are filled with sand, allowing groundwater to seep into them and be discharged through them. The compaction piles are filled with lime, which allows the lime inside to react with the groundwater to produce a hydration heat reaction, reducing the groundwater content.

[0021] Optionally, the filter piles and compaction piles are arranged in a quincunx pattern with a pile spacing of 1 to 1.5 m.

[0022] By adopting the above technical solution, filter piles are set around the compaction piles. The filtering effect of the filter piles can reduce the groundwater flowing into the compaction piles, so that the lime in the compaction piles can undergo hydration heat reaction with as little as possible. At the same time, compaction piles are also set around the filter piles. When there is a lot of groundwater and the filter piles cannot drain the groundwater in time, the compaction piles can absorb some of the groundwater.

[0023] Optionally, one end of the drainage pipe is installed inside the filter pile, and the other end is connected to the drainage ditch.

[0024] By adopting the above technical solution, based on the siphon principle, the groundwater rising in the filter pile can be discharged into the drainage ditch through the drainage pipe, thereby reducing the water content in the foundation and making the roadbed structure more stable.

[0025] Optionally, the drainage pipe gallery is composed of multiple box-shaped concrete pipes spliced ​​together, and the top of the box-shaped concrete pipes is provided with water-permeable holes.

[0026] By adopting the above technical solution, water in the embankment can seep into the drainage pipe gallery and be discharged through the drainage pipe gallery. At the same time, groundwater in the foundation is less likely to rise into the embankment and affect the embankment structure.

[0027] Optionally, the filter layer is laid with pebbles with a particle size of 40-60mm and a thickness of 60mm.

[0028] By adopting the above technical solution, when the water stored in the embankment seeps into the drainage pipe gallery, it needs to pass through a filter layer. The installation of the filter layer reduces the possibility of the water flow carrying away the soil in the embankment.

[0029] Optionally, the pore size of the permeable holes is smaller than the minimum pebble size in the filter layer.

[0030] By adopting the above technical solution, it is difficult for the pebbles in the filter layer above the drainage pipe gallery to fall from the filter holes into the box-type concrete pipe.

[0031] Optionally, the embankment earthwork is laid in layers with geogrids between each layer, and both sides of the embankment are wrapped with geogrids.

[0032] By adopting the above technical solution, earthwork grids are installed in the embankment earthwork, which makes the embankment structure more resistant to slippage and sliding, and makes the road surface less prone to landslides or shear failure due to embankment earthwork.

[0033] Optionally, vegetation slope protection can be provided on both sides of the embankment.

[0034] By adopting the above technical solutions and planting vegetation on both sides of the embankment, the embankment slope becomes more stable, the environment on both sides of the embankment becomes more beautiful, and the pedestrian experience on the road is better.

[0035] Optionally, the compaction pile is filled with lime and admixtures, including fly ash, slag and volcanic ash.

[0036] By adopting the above technical solution, when the lime inside the compacted pile reacts with the groundwater to generate heat of hydration, the porosity generated inside the pile after the lime pile expands can be reduced, and the possibility of the lime pile core softening can be reduced.

[0037] In summary, this application includes at least one of the following beneficial effects:

[0038] 1. Construct filter piles in soft soil foundations and install drainage pipes in compaction piles so that groundwater in the foundation can be discharged into drainage ditches through compaction piles and drainage pipes, thereby reducing the impact of groundwater on the foundation.

[0039] 2. Constructing compaction piles filled with lime in soft foundations can compact the soil between the piles and absorb moisture from the foundation, thus reducing the moisture content of the foundation.

[0040] 3. A drainage pipe gallery is set up above the foundation to separate the embankment from the foundation soil. On the one hand, rainwater stored in the embankment can be directly discharged to the outside of the embankment through the drainage pipe gallery. On the other hand, the impact of groundwater in the foundation on the embankment soil is reduced.

[0041] 4. Installing geogrids within the embankment soil enhances the embankment's shear and slip resistance, making the embankment structure more stable. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the construction layout of the filter piles and compaction piles in the embodiments of this application;

[0043] Figure 2 This is a cross-sectional schematic diagram of the soil layer, embankment, and pavement in an embodiment of this application;

[0044] Figure 3 yes Figure 2 Enlarged view of point A in the middle;

[0045] Figure 4 This is a schematic diagram of the overall structure of the box-type concrete pipe according to an embodiment of this application.

[0046] Explanation of reference numerals in the attached drawings: 1. Filter pile; 2. Compaction pile; 3. Drainage pipe; 4. Drainage ditch; 5. Drainage pipe gallery; 51. Box-type concrete pipe; 511. Permeable hole; 512. Rib; 513. Edge; 514. Groove; 6. Filter layer; 7. Embankment; 8. Geogrid; 9. Road surface. Detailed Implementation

[0047] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0048] This application discloses a method for constructing an embankment on a soft foundation, comprising the following steps:

[0049] S1. Construct filter pile 1 and compaction pile 2. (Refer to...) Figure 1 and Figure 2 Filter piles 1 and compaction piles 2 were constructed on the original soft foundation. Filter piles 1 were sand piles, and compaction piles 2 were lime piles. During the construction of filter piles 1, a mobile pile driver was first used to form holes. After the holes were formed, medium-coarse sand was poured into them. The permeability coefficient of the medium-coarse sand was not less than 5 × 10⁻⁶. -3 The flow rate is cm / s, the mud content is not greater than 5%, and the medium-coarse sand needs to be compacted. The core of filter pile 1 is filled with pebbles with a particle size of 10-30mm.

[0050] Reference Figure 1During the construction of compaction pile 2, the pile hole is first formed using the driven pipe method. After the pile hole is completed, lime is rammed into the pile hole. The lime rammed into the pile hole must be fresh, lumpy lime that has been crushed and sieved to form a particle size no larger than 20mm, and must not contain stones or organic impurities. Depending on the actual geological conditions, fly ash, slag, volcanic ash, and other admixtures should also be added to the lime according to the design ratio to enhance the strength of the compaction pile 2 and reduce the possibility of core softening. When ramming the lime mixed with admixtures into the pile hole, it is necessary to backfill and compact it in layers, with each backfill layer being 250mm-400mm thick.

[0051] Reference Figure 1 and Figure 2 The compaction piles 2 and the filter piles 1 are arranged in a quincunx pattern with a spacing of 1-1.5m. By arranging the compaction piles 2 and the filter piles 1 in a quincunx pattern, the filter piles 1 can discharge more groundwater and reduce the absorption of groundwater by the compaction piles 2. At the same time, the compaction piles 2 can assist the filter piles 1 in absorbing groundwater when the filter piles 1 cannot discharge groundwater in time, thereby reducing the impact of groundwater on the foundation under the road surface 9.

[0052] S2. Construction drainage pipe 3. (Refer to...) Figure 2 and Figure 3 During the construction of the filter pile 1, a drainage pipe 3 is buried in the core of each filter pile 1. The drainage pipe 3 is made of PE pipe, which makes the drainage pipe 3 less prone to rust and corrosion and can be buried underground. One end of the drainage pipe 3 is buried at 1 / 3 depth of the filter pile 1, and the other end is laid to both sides of the embankment 7.

[0053] S3. Construction drainage ditch 4. (Refer to...) Figure 2 and Figure 3 During the construction of compaction piles 2 and filter piles 1, drainage ditches 4 on both sides of the embankment 7 toe can be constructed simultaneously. The construction of drainage ditches 4 involves excavating open ditches on both sides of the embankment 7, and one end of the drainage pipe 3 in each filter pile 1 is connected to the drainage ditch 4. The drainage ditch 4 is set up so that the groundwater in the filter piles 1 can flow into the drainage ditch 4 along the drainage pipe 3, and at the same time, it reduces the possibility of water accumulation on both sides of the road eroding and soaking the foundation.

[0054] S4. Construction of drainage pipe gallery 5. (Refer to...) Figure 2 and Figure 4 After the drainage pipe 3 is laid, the foundation soil is backfilled, and the drainage pipe gallery 5 is laid on the backfilled foundation soil. The drainage pipe gallery 5 is specifically composed of multiple prefabricated box-shaped concrete pipes 51 spliced ​​along the road path. Multiple ribs 512 are arranged parallel and spaced inside the box-shaped concrete pipes 51. By setting multiple ribs 512, the box-shaped concrete pipes 51 can bear the weight of the overlying soil and the load of vehicles on the road surface 9.

[0055] Reference Figure 2 and 4 After the box-type concrete pipe 51 is laid, several permeable holes 511 are opened on the side away from the drainage pipe 3. The permeable holes 511 allow the water accumulated in the embankment 7 structure above the drainage pipe gallery 5 to seep into the drainage pipe gallery 5 through the permeable holes 511 and be discharged along the drainage pipe gallery 5.

[0056] Reference Figure 4 Each box-type concrete pipe 51 has a retaining edge 513 and a retaining groove 514 at both ends. The retaining edge 513 is used to insert and cooperate with the retaining groove 514 of the adjacent box-type concrete pipe 51. When splicing two box-type concrete pipes 51, it is only necessary to insert the retaining edge 513 into the retaining groove 514 and apply anti-seepage mortar to the joint to achieve the connection between the two box-type concrete pipes 51.

[0057] S5. Construction of the filter layer 6. (Refer to...) Figure 2 After the construction of the drainage pipe gallery 5 is completed, a filter layer 6 is constructed above the drainage pipe gallery 5. The filter layer 6 is specifically constructed by laying pebbles with a particle size of 40-60mm on top of the box-type concrete pipe 51, with a thickness of 60mm. The permeable holes 511 on the box-type concrete pipe 51 have a smaller diameter than the minimum particle size of the pebbles in the filter layer 6. By setting up the filter layer 6, the accumulation of sand and soil in the embankment 7 structure above the drainage pipe gallery 5 under the influence of water flow can be reduced, thus preventing the blockage of the permeable holes 511 of the box-type concrete pipe 51 and reducing the drainage effect of the drainage pipe gallery 5.

[0058] S6. Lay the earthwork for embankment 7, and install geogrid 8 within the earthwork for embankment 7. (Refer to...) Figure 2 After the filter layer 6 is completed, backfill soil on top of the filter layer 6 to form the embankment 7. The soil needs to be backfilled and compacted in layers. After each layer of soil is backfilled and compacted, a geogrid 8 is laid. The geogrid 8 is a unidirectional geogrid 8. Taking the first and second layers of soil as an example, after cleaning the foundation surface, backfill the first layer of soil and compact it. Then, lay the geogrid 8 along the width of the road, leaving a geogrid 8 with a edging length of not less than 100cm on both sides of the road. After the geogrid 8 in the first layer of soil is laid, backfill and compact the second layer of soil. Roll up the edging of the geogrid 8 reserved in the first layer and lay it on top of the second layer of soil. When laying the geogrid 8 on the second layer of soil, stitch the geogrid 8 rolled up during the construction of the first layer of soil to the geogrid 8 laid on the second layer of soil. The specific stitching method is to use No. 8 iron wire to tie two layers of geogrid 8 in a "Z" shape to complete the stitching and fixation. The overlap width of the two layers of geogrid 8 is not less than 50cm.

[0059] S7. Construction pavement 9. (Refer to...) Figure 2 After the embankment 7 is completed, the road surface 9 is constructed on the surface of the embankment 7 according to the design requirements. After the road surface 9 is completed, vegetation is planted on both sides of the embankment 7. This reduces the risk of landslides on both sides of the embankment 7, and the vegetation can also cover the geogrid 8 and the soil of the embankment 7, making the view better for pedestrians.

[0060] The implementation principle of the embankment construction method for soft foundations in this application embodiment is as follows: Before constructing the pavement 9, the original soft foundation is first treated by driving filter piles 1 and compaction piles 2 into the foundation to enhance the bearing capacity of the foundation and reduce the groundwater in the foundation, thereby reducing the possibility of local settlement or collapse. After construction, the water accumulated in the filter piles 1 is discharged into the drainage ditch 4 through the drainage pipe 3, so that the groundwater in the foundation can be discharged to the outside for a long time. After constructing the drainage pipe gallery 5 above the foundation, a filter layer 6 is laid on top of the drainage pipe gallery 5. After the filter layer 6 is constructed, the embankment 7 soil is backfilled in layers, and a geogrid 8 is added in each layer of embankment 7 soil to enhance the stability of the embankment 7 structure. Finally, the pavement 9 structure is constructed on top of the embankment 7 structure.

[0061] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for constructing embankments on soft foundations, characterized in that: Includes the following steps: S1. Construct filter piles (1) and compaction piles (2) within the foundation. S2. Construction drainage pipe (3); S3. Drainage ditches (4) are constructed on both sides of the embankment (7); S4. Construct a drainage pipe gallery on the foundation (5); S5. Lay a filter layer (6) above the drainage pipe gallery (5); S6. Lay the earthwork of the embankment (7) and install geogrid (8) in the earthwork of the embankment (7). S7. Construction pavement (9); The filter piles (1) and compaction piles (2) are arranged in a quincunx pattern with a pile spacing of 1~1.5m; One end of the drainage pipe (3) is set inside the filter pile (1), and the other end is connected to the drainage ditch (4). The drainage pipe gallery (5) is spliced ​​together from multiple box-shaped concrete pipes (51), and the top of the box-shaped concrete pipes (51) is provided with water-permeable holes (511). The diameter of the permeable hole (511) is smaller than the minimum pebble particle size in the filter layer (6).

2. The embankment construction method for soft foundations according to claim 1, characterized in that: The filter pile (1) is a drainage sand pile, and the compaction pile (2) is a lime pile.

3. The embankment construction method for soft foundations according to claim 1, characterized in that: The filter layer (6) is laid with pebbles with a particle size of 40-60mm and a thickness of 60mm.

4. The embankment construction method for soft foundation according to claim 1, characterized in that: The embankment (7) is laid in layers with geogrid (8) between each layer, and both sides of the embankment (7) are wrapped with geogrid (8).

5. The embankment construction method for soft foundation according to claim 1, characterized in that: Vegetated slope protection is provided on both sides of the embankment (7).

6. The embankment construction method for soft foundation according to claim 2, characterized in that: The compaction pile (2) is filled with lime and admixtures, including fly ash, slag and volcanic ash.

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