High-fill reinforced soil slope construction method capable of avoiding repeated excavation of deep foundation pit at slope top

Abstract

The invention relates to a high-fill reinforced soil side slope construction method for avoiding repeated excavation of a deep foundation pit at the top of a slope. Reinforced geosynthetics are laid in a layered mode, and cohesive soil is rolled to the position below the topmost side slope in a layered mode; according to the position where a foundation pit needs to be excavated subsequently, prefabricated reinforced concrete retaining walls are laid in a layered mode, reinforced geosynthetics are laid on the peripheries of the reinforced concrete retaining walls in a layered mode, cohesive soil is rolled to the top face of the terrace in a layered mode, operation is started from the interior of the reserved foundation pit, and an underground building on the slope top is constructed; according to the method, synchronous construction of the prefabricated reinforced concrete retaining wall and backfill is adopted, and the problem that secondary excavation such as foundation pit supporting excavation is adopted after slope construction is completed is solved; the scheme that the slope body of the side slope outside the retaining wall is reinforced by adopting the reinforced geosynthetics is not influenced, so that the slope ratio of the slope surface of the side slope can be reasonably reduced, and the land is saved.

Description

Technical Field

[0001] The invention relates to the technical field of slope engineering, and in particular to a high fill reinforced soil slope construction method without repeated excavation of a deep foundation pit at the top of the slope. Background Art

[0002] The design of existing reinforced soil slopes follows the provisions of GB 50330-2013 "Technical Specifications for Building Slope Engineering", GB / T50290-2014 "Technical Specifications for Application of Geosynthetics", and GB 51254-2017 "Technical Specifications for High Fill Foundation". The slope design is considered separately from the construction of the top structures, that is, the top structures are constructed after the slope construction is completed. When it is necessary to construct top structures such as fire water tanks, if there is a foundation trench that needs to be excavated, the reinforced soil slope needs to be excavated, which will damage the reinforcement, thus affecting the overall stability of the slope and even endangering the safety of the slope.

[0003] For example, the "high fill slope device and construction method, grouting composite material and application for airport engineering" disclosed in patent publication number CN117888558A includes a stone slope body piled on the construction site of the high fill slope of the airport engineering, and a grid arranged on the stone slope body. Through the stone slope body, the main body of the high fill slope is set, the raw materials located inside are wrapped in layers, and the outer packaging body located at the slope part is in a stacked distribution state, which solves the technical problem of covering the slope part as a whole when the earth and stone filling and reinforced soil slope construction are all done, thereby improving the stability of the high fill slope of the airport engineering;

[0004] For example, the patent publication number CN117431978A discloses a "reinforced soil steep slope and its construction method". In the steep slope, the deformation energy absorption zone includes an L-shaped mesh and a stone assembly. The reinforced composite includes a reinforced soil body, a reinforcing material and a geobag assembly. The geobag assembly is arranged in the reinforced soil body and is located on the side of the reinforced soil body away from the existing steep slope. The reinforcing material is laid in the reinforced soil body and wraps the geobag assembly. The side of the geobag assembly, the bottom of the L-shaped mesh and the side of the L-shaped mesh constitute a stone accommodating space. The stone accommodating space is filled with the stone accommodating space, which solves the problem in the prior art that the lateral earth pressure generated by the reinforced soil of the reinforced soil structure directly acts on the slope protection layer, causing the slope protection layer to deform horizontally and the reinforcement effect of the reinforcing material is insufficient.

[0005] The above-mentioned prior art is only applicable to projects such as airports where the fill surface is used as a roadbed or the top of the slope of an aircraft taxiway, etc., and no excavation is required. When the top of the slope needs to be excavated, the reinforced structure of the surface will be destroyed.

[0006] The existing theories and design methods of reinforced soil slopes are mainly designed to solve high fill slopes such as road projects and airport projects. Their characteristics are high fill height of the slope and no secondary excavation is required at the top of the slope. At the same time, the slope is less sensitive to deformation and a certain amount of deformation is allowed.

[0007] However, in construction projects, especially industrial buildings represented by substations, the processes involved are complex. At the same time, the land inside the substation is scarce, and it is often necessary to excavate some underground structures within the wall. That is, after the slope construction is completed, ground excavation is required within the range of the slope top, involving secondary excavation within the range of reinforced soil of the slope. When reinforced soil slope construction is adopted, it is necessary to cancel the geosynthetics within the excavation depth range, so that the safety factor of the top slope is reduced, or it is necessary to use a non-reinforced slope instead. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a high fill reinforced soil slope construction method without repeated excavation of a deep foundation pit at the top of the slope to solve the above problems.

[0009] The present invention provides the following technical solutions:

[0010] A high fill reinforced soil slope construction method without repeated excavation of a deep foundation pit at the top of a slope comprises the following steps:

[0011] Remove the loose soil on the surface at the foot of the slope;

[0012] Lay reinforced geosynthetics in layers and roll clay soil in layers to the bottom of the top slope;

[0013] According to the location of the foundation pit to be excavated later, prefabricated reinforced concrete retaining walls are laid in layers, reinforced geosynthetics are laid in layers on the outer periphery of the reinforced concrete retaining walls, and clay soil is rolled in layers. The height of the retaining plate is higher than the top of the clay soil rolled in layers;

[0014] Roll the floor layer by layer until it reaches the top surface, start working from the reserved foundation pit, and construct the underground building on the top of the slope;

[0015] Use sand or clay to backfill and compact the gap between the underground building on the top of the slope and the reinforced concrete retaining wall.

[0016] Preferably, the surface loose soil at the foot of the slope is removed and a layer of anti-seepage board is set below the ground surface. The reinforced geosynthetics are laid starting from the anti-seepage board at the foot of the slope to meet the bearing capacity requirements of the foundation below the foot of the slope.

[0017] Preferably, after removing the loose soil on the surface of the slope foot, a slope foot retaining structure is set at the corner of the slope foot, and the slope foot retaining structure adopts a gravity retaining wall.

[0018] Preferably, the slope has a multi-step structure, and the slope of each step is the same, which is 1:1.75; before laying the reinforced geosynthetics in layers, the original soil slope surface of the slope is trimmed to have a multi-step structure.

[0019] Preferably, a first graded gravel drainage channel is arranged on the original soil slope surface of the trimmed slope, and the first graded gravel drainage channel is wrapped with a layer of non-woven fabric.

[0020] Preferably, a second graded gravel drainage channel connected to the first graded gravel drainage channel is horizontally arranged in the slope of each step.

[0021] Preferably, a drainage ditch is provided at the top of the slope of each step.

[0022] Preferably, after the construction of the underground building is completed, part of the reinforced concrete retaining wall is removed from top to bottom, so that the remaining reinforced concrete retaining wall is located below the ground.

[0023] Preferably, the reinforced geosynthetics are geogrids or woven geotextiles or reinforced tapes.

[0024] Preferably, a net is hung on the slope surface of the slope and grass is sprayed and planted.

[0025] The present invention has the following beneficial technical effects:

[0026] In the project of high reinforced soil slope, it is necessary to excavate a certain depth at the top of the slope to cast underground reinforced concrete structure. The present invention adopts the synchronous construction of prefabricated reinforced concrete retaining wall (foundation pit support structure) and backfill soil, so as to avoid the problem of secondary excavation such as foundation pit support excavation after the slope construction is completed.

[0027] The prefabricated reinforced concrete retaining wall (foundation pit support structure) is used together with the fill slope for layered rolling construction, which does not affect the slope body outside the retaining wall. The slope body is reinforced with reinforced geosynthetics, which can reasonably reduce the slope rate of the slope surface and save land;

[0028] The reinforced concrete retaining wall (support structure) that meets the requirements of layered compaction and is prefabricated in sections saves the construction period on site. At the same time, the underground foundation pit support structure for subsequent slope top excavation has high strength and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the present invention.

[0030] Figure 2 It is a schematic diagram of construction step 1 of the present invention;

[0031] Figure 3 It is a schematic diagram of the second construction step of the present invention;

[0032] Figure 4 It is a schematic diagram of construction step three of the present invention;

[0033] Figure 5 It is a schematic diagram of construction step 4 of the present invention;

[0034] Figure 6 It is a schematic diagram of construction step five of the present invention.

[0035] The reference numerals in the figure are:

[0036] 1. Retaining structure at the foot of the slope; 2. Anti-seepage plate at the foot of the slope; 3. Reinforced geosynthetics; 4. First-level gravel drainage channel; 5. Second-level gravel drainage channel; 6. Underground buildings; 7. Reinforced concrete retaining wall; 8. Fence wall; 9. Drainage ditch. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example:

[0039] A high fill reinforced soil slope construction method without repeated excavation of deep foundation pits on the top of the slope, such as Figure 1-6 As shown:

[0040] The reinforced geosynthetics 3 may be geogrids, woven geotextiles or reinforced tapes; the backfill soil is non-permeable raw soil.

[0041] (1) Figure 2 As shown, the surface soil at the foot of the slope is removed and sunken below the ground surface. A layer of anti-seepage board 2 is set on the sunken ground surface after excavation, and a retaining structure 1 is constructed. If necessary, measures such as replacement and filling can be taken to meet the bearing capacity requirements of the foundation below the foot of the slope; the reinforced geosynthetics 3 are laid below the surface of the site floor, and the reinforced geosynthetics 3 on the top work together with the foundation soil to participate in the stability calculation of the slope;

[0042] The anti-seepage plate 2 at the foot of the slope is relatively located between the retaining structure 1 at the foot of the slope and the original soil edge of the slope;

[0043] Excavate the original soil of the slope and the surface loose soil of the slope to form a multi-step structure, and lay the first graded gravel drainage channel 4. The first graded gravel drainage channel 4 can adopt a 500 thick graded gravel drainage channel, and a layer of non-woven fabric is wrapped around the 500 thick graded gravel drainage channel.

[0044] (2) Figure 3 As shown, starting from the foot of the slope that is sunken below the ground surface (the anti-seepage plate 2 at the foot of the slope), the reinforced geosynthetics 3 are laid in layers and the clay soil is rolled in layers to form a slope, and the slope has a multi-step structure;

[0045] The topmost step is used to set up the underground building 6. Except for the first step used to build the underground building 6, the rest of the slope is layered with reinforced geosynthetics 3 and layered with clay to form the slope in sequence;

[0046] The slope of each step formed by the slope is the same, which is 1:1.75, further reducing the scope of the slope land and realizing the green construction of the slope project; a drainage ditch 9 is set on the top of each step formed by the slope, and a second graded gravel drainage channel 5 is horizontally built in each step formed by the slope, and each second graded gravel drainage channel 5 is connected to a 500 thick graded gravel drainage channel at one end in the same direction.

[0047] (3) Figure 4 As shown, the top step of the slope is laid with prefabricated reinforced concrete retaining wall 7 in layers according to the location of the foundation pit to be excavated later, while avoiding the location where the foundation pit needs to be excavated, laying reinforced geosynthetics 3 in layers and compacting clay in layers. When the reinforced geosynthetics 3 conflict with the location, the reinforced geosynthetics 3 are laid in a bypassing manner; the reinforced concrete retaining wall 7, reinforced geosynthetics 3 and compacting of clay in the same layer are carried out simultaneously; the height of the reinforced concrete retaining wall 7 is slightly higher than the top of the clay to be compacted in layers, and can usually be more than 200 mm high.

[0048] (4) Figure 5 As shown, the ground is rolled layer by layer to the top surface of the floor (the top step of the slope), and then the work starts from the reserved foundation pit, and the underground building 6 on the top of the slope is cast in situ and poured to the ground;

[0049] Normally, the reinforced concrete retaining wall 7 is 0.8m to 1.2m wider than the outer width of the underground building 6 to be poured;

[0050] (5) Figure 6 As shown, the gap between the underground building 6 on the top of the slope and the reinforced concrete retaining wall 7 of the reserved foundation pit is backfilled and compacted with sand or clay, and the reinforced concrete retaining wall 7 within a certain depth below the ground is removed, and then the road surface (ground) structure layer is constructed.

[0051] Through the above construction steps, the excavation requirements of the underground building 6 on the top of the slope and the calculation scheme of setting the reinforced geosynthetics 3 in the highest level of the high slope to reinforce the slope are met at the same time. Under the premise of ensuring safety, the slope rate of the top level of the slope is increased, and the area occupied by the high fill slope is further reduced;

[0052] The support structure of the deep foundation pit excavated on the top of the slope adopts a prefabricated reinforced concrete retaining wall 7 structure, which can be constructed simultaneously with the slope filling and rolling construction process. Under the premise of meeting safety requirements, the secondary excavation of the deep foundation pit is avoided, the construction period is shortened, and the safety of the subsequent construction of the underground building 6 on the top of the slope is guaranteed;

[0053] The disturbance and damage to the completed reinforced soil slope caused by secondary foundation pit support and excavation in the reinforced soil slope is avoided, which significantly improves the design quality.

[0054] The above-mentioned embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A high fill reinforced soil slope construction method without repeated excavation of deep foundation pits on the top of the slope, characterized in that: The following steps are involved: Remove the loose soil on the surface at the foot of the slope; Laying reinforced geosynthetics (3) in layers and rolling clay soil in layers to below the topmost slope; According to the location of the foundation pit to be excavated later, prefabricated reinforced concrete retaining wall (7) is laid in layers, reinforced geosynthetics (3) are laid in layers on the periphery of the reinforced concrete retaining wall (7) and clay soil is rolled in layers, and the height of the retaining plate is higher than the top of the clay soil rolled in layers; Roll the floor in layers until it reaches the top surface, start working from the reserved foundation pit, and construct the underground building on the top of the slope (6); The gap between the underground building (6) and the reinforced concrete retaining wall (7) at the top of the slope is backfilled and compacted with sand or clay.

2. The method for constructing a high fill reinforced soil slope without repeated excavation of a deep foundation pit at the top of a slope according to claim 1, characterized in that: The surface loose soil at the foot of the slope is removed and the soil is sunken below the ground surface to provide a layer of anti-seepage board (2) at the foot of the slope. The reinforced geosynthetics (3) are laid starting from the anti-seepage board (2) at the foot of the slope to meet the bearing capacity requirements of the foundation below the foot of the slope.

3. The method for constructing a high fill reinforced soil slope without repeated excavation of a deep foundation pit on the top of a slope according to claim 1, characterized in that: After removing the loose soil on the surface of the slope foot, a slope foot retaining structure (1) is set at the corner of the slope foot, wherein the slope foot retaining structure adopts a gravity retaining wall.

4. The method for constructing a high fill reinforced soil slope without repeated excavation of a deep foundation pit at the top of a slope according to claim 1, characterized in that: The side slope has a multi-step structure, and the slope rate of each step is the same, which is 1:1.

75. Before the reinforced geosynthetics (3) are laid in layers, the original soil side slope surface of the side slope is trimmed to have a multi-step structure.

5. The method for constructing a high-fill reinforced soil slope without repeated excavation of a deep foundation pit on the top of a slope according to claim 4, characterized in that: A first graded gravel drainage channel is arranged on the original soil slope surface of the trimmed slope, and the first graded gravel drainage channel is wrapped with a layer of non-woven fabric.

6. A high fill reinforced soil slope construction method for avoiding repeated excavation of deep foundation pits at the top of a slope according to claim 5, characterized in that: A second graded gravel drainage channel communicating with the first graded gravel drainage channel is horizontally arranged in the side slope of each step.

7. The method for constructing a high fill reinforced soil slope without repeated excavation of a deep foundation pit at the top of a slope according to claim 5, characterized in that: A drainage ditch (9) is provided on the top of the side slope of each step.

8. The method for constructing a high fill reinforced soil slope without repeated excavation of a deep foundation pit at the top of a slope according to claim 1, characterized in that: After the construction of the underground building (6) is completed, part of the reinforced concrete retaining wall (7) is removed from top to bottom, so that the remaining reinforced concrete retaining wall (7) is located below the ground.

9. The method for constructing a high fill reinforced soil slope without repeated excavation of a deep foundation pit at the top of a slope according to claim 1, characterized in that: The reinforced geosynthetics (3) are geogrids or woven geotextiles or reinforced tapes.

10. The method for constructing a high fill reinforced soil slope without repeated excavation of a deep foundation pit at the top of a slope according to claim 1, characterized in that: A net is hung on the slope surface of the side slope and grass is sprayed and planted.

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