A construction method for partition reinforcement and bearing capacity improvement of a large-area soft soil foundation
By using a zoned, cyclical paving method with inverted T-shaped main roads and branch roads, the problems of high construction risk and low efficiency caused by direct mechanical action in soft soil foundation construction are solved, thereby improving construction safety and quality. This method is suitable for rapid construction in large areas of soft soil foundations and silt backfill areas.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NO 3 ENG COMPANY LTD OF CCCC FIRST HARBOR ENG COMPANY
- Filing Date
- 2026-03-27
- Publication Date
- 2026-07-28
AI Technical Summary
When constructing in soft soil foundations or silt-filled areas, the direct action of machinery on low-bearing-capacity foundations leads to high construction risks, low efficiency, and difficulty in ensuring quality, resulting in silt heave and grout leakage, which are difficult to effectively solve with existing technologies.
The construction method of zoned cyclic paving and dynamic channel conversion is adopted. By combining the inverted T-shaped main road and branch road, it is ensured that the construction machinery always operates on the stable working surface with the established bearing capacity, avoiding direct impact on untreated areas. Medium and coarse sand, fine sand or their mixture and steel plates are used for paving to form a stable sand cushion layer.
It effectively prevents silt heave and grout leakage, ensures uniform sand cushion thickness, improves construction safety and efficiency, and is suitable for rapid construction in large areas of soft soil foundations and silt backfill areas.
Smart Images
Figure CN121915722B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of soft soil foundation zonal reinforcement construction technology, specifically a construction method for zonal reinforcement and bearing capacity enhancement of large-area soft soil foundations. Background Technology
[0002] When constructing sand cushion layers in soft soil foundations or silt-backfilled areas, there is a common construction risk caused by construction machinery directly acting on the low-bearing-capacity foundation surface. Silt layers have low strength and poor load-bearing capacity. When construction machinery moves or operates, it is easy to generate local stress concentration, which can lead to silt heave and grout leakage. In severe cases, it may even damage the already laid drainage boards, membrane bags, or other auxiliary structures, causing rework or delays in the project.
[0003] In existing technologies, measures such as laying sand in thin layers in stages or pre-laying geotextile under the sand cushion layer are often used. Although these measures improve the stability of mechanical construction to some extent, they still have the following shortcomings: Low construction efficiency: Thin-layer sand laying or pre-laying geotextile increases the number of construction cycles and the construction period is long, making it difficult to meet the needs of rapid construction of large-area soft soil foundations. High construction safety risks: Direct mechanical action on weak bearing foundations may still cause local heave and grout leakage, posing safety hazards; Construction quality is difficult to guarantee: the sand-laying machinery is unstable, which can easily lead to uneven thickness of the sand cushion layer and difficulty in controlling the elevation load, thus affecting the quality of subsequent projects.
[0004] Therefore, there is an urgent need for a foundation construction method that can effectively control the bearing capacity of the foundation and avoid silt uplift while ensuring the safe operation of machinery, so as to improve construction efficiency, ensure the quality of sand cushion layer, and be suitable for widespread application in large areas of soft soil foundation or silt backfill areas. Summary of the Invention
[0005] The purpose of this invention is to provide a construction method for zonal reinforcement and bearing capacity enhancement of large-area soft soil foundations, applicable to vacuum preloading construction with sand. Through zonal cyclic paving and dynamic channel conversion, the construction machinery always operates on a stable working surface that has already formed bearing capacity, avoiding large-area soft soil from directly being loaded and becoming unstable, reducing the risk of settlement, and improving the overall bearing capacity and construction safety of the foundation.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: A construction method for zonal reinforcement and bearing capacity enhancement of large-area soft soil foundations, the construction method comprising: S1. Before construction, the construction site is divided into zones based on the construction area, the foundation bearing capacity test results, and the design thickness of the sand cushion layer. A T-shaped main road is prioritized along the length of the construction area as a temporary passage for construction machinery. The T-shaped main road consists of a longitudinal main road and a transverse distribution road. The main road is paved using a composite method of crushed stone leveling and steel plate laying, laid in a staggered pattern along the direction of machinery travel, with an overlap length of not less than 30cm. Several branch roads are laid sequentially on both sides of the transverse distribution road. The steel plate laying method and structural form of the branch roads are consistent with those of the main road, and they are used for subsequent segmented sand paving construction. S2. Construction machinery enters the transverse distribution channel via the inverted T-shaped main road, prioritizing the outermost branch road 1 as the first working surface for sand cushion layer construction; the sand cushion layer construction of the branch road adopts the method of first constructing the branch road, then the two sides. S3. After the sand cushion layer is laid in branch road 1 and the corresponding construction areas on both sides, the construction machinery will advance in the following order: the steel plate channel will be laid in branch road 2 during the construction of branch road 1, but sand will not be laid immediately; after the completion of branch road 1, the construction machinery will be transferred to branch road 2 through the transverse distribution channel, and the sand cushion layer and the construction of the areas on both sides of branch road 2 will be completed in the same way as branch road 1; after the construction of branch road 2 is completed and a stable working surface is formed, the steel plates in the area of branch road 1 will be removed section by section and transferred to branch road 3. S4. Following the method of laying sand in front and removing slabs behind, complete the subsequent construction sections such as branch road 3 and branch road 4 in sequence until the sand cushion layer of the entire construction area is laid.
[0007] By using the above methods, construction machinery can always operate on steel plates or pre-formed sand cushions, avoiding direct operation across untreated areas and effectively preventing silt uplift and grout leakage.
[0008] In S1, the longitudinal main channel is 5-8m wide and the transverse distribution channel is 4-6m wide. Sand is transported to the construction area by mechanical means to ensure that the construction machinery operates on a solid working surface and completes the sand cushion layer laying. The crushed stone has a particle size of 20-40mm and a thickness of not less than 20cm. The steel plate has a specification of 1.2-2.0m × 6-8m. On both sides of the transverse distribution channel, several branch roads are laid out at intervals of 10-20m, and the width of the branch roads is controlled at 2-4m.
[0009] The sand includes medium-coarse sand, fine sand, or a mixture thereof. The construction machinery includes small agricultural transport vehicles, small dump trucks, and small excavators. The single transport volume is 1.0 to 3.0 m³, which is adjusted according to the type of machinery and the bearing capacity of the construction surface.
[0010] The construction method for S2 is to first construct the branch roads and then the two sides. The specific operation is as follows: Construction on S21 and Branch Road 1: Transport vehicles travel along the main road and the steel plate channel of the branch road to the end of the branch road to unload sand; the single transport volume is controlled between 1.0 and 3.0 m³ according to the type of machinery, of which small agricultural transport vehicles should be controlled between 1.0 and 1.5 m³, and small dump trucks should be controlled between 2.0 and 3.0 m³; after unloading sand, it is spread by small excavators or manual labor, and the initial leveling thickness is 5 to 10 cm higher than the design thickness; the backward sand spreading method is adopted, and the machinery always operates on the already laid sand cushion layer or steel plate channel. It is strictly forbidden to walk or turn directly on the original silt surface; Construction on both sides of S22 and Branch Road 1: After the sand cushion layer of branch road 1 forms a stable working zone, sand cushion layers are laid in adjacent areas on both sides with branch road as the center. During construction, the thickness of the sand cushion layer is controlled by side stakes, with a density of one side stake every 10-20 square meters, and the marking height corresponds to the design top elevation of the sand cushion layer. After the sand cushion layer is laid, it is leveled in time and a 0.3%-0.5% slope is formed to ensure smooth drainage.
[0011] Before laying the sand cushion layer, set up edge stakes every 10 to 20 m² in the construction site to control the thickness of the cushion layer, and mark the edge stakes at a certain height to monitor the thickness of the sand cushion layer.
[0012] The construction method described herein is applicable to the laying of sand cushion layers in large areas of soft soil foundations, silt backfill areas, and other low-bearing-capacity sites. The width of the passage, the thickness of the sand, and the type of machinery can be flexibly adjusted according to the site conditions.
[0013] The technical effects of this invention are as follows: 1. Avoid direct application of construction machinery to weak bearing foundations to prevent silt heave and grout leakage; 2. Ensure uniform thickness and accurate elevation of the sand cushion layer to improve construction quality; 3. Construction machinery always operates on a solid working surface to improve construction safety; 4. The cyclical advancement and segmented construction method improves construction efficiency and is suitable for large-area soft soil foundations and silt backfilling areas. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the sand-laying path structure in the construction method of the present invention.
[0015] Figure 2 This is a schematic diagram illustrating the construction sequence of the present invention. Detailed Implementation
[0016] Example 1
[0017] like Figure 1The sand-paving path structure shown includes an inverted T-shaped main road and multiple branch roads. The inverted T-shaped main road consists of a longitudinal main channel and a transverse distribution channel. The longitudinal main channel has a width of 5-8m, and the transverse distribution channel has a width of 4-6m. Several branch roads are arranged sequentially on both sides of the transverse distribution channel.
[0018] Example 2
[0019] In the construction of a silt-filling area in a certain project, the original foundation bearing capacity was less than 20 kPa. After adopting the path structure in Example 1, by setting up a 6m wide inverted T-shaped main road and a 3m wide branch road, the average daily sand cushion layer laying area was increased by about 30% compared with the traditional construction method. No silt heave or grouting occurred during the construction period, and the thickness deviation of the sand cushion layer was kept within ±2cm, and the construction effect was good.
[0020] In actual construction, the medium-coarse sand cushion layer laying method of the present invention is implemented according to the following steps: 1. Construction preparation and machinery scheduling Before construction, the scope of the construction area is determined, the bearing capacity of the foundation is assessed, and the layout of the main roads and auxiliary branch roads is planned.
[0021] Transportation and construction machinery are uniformly dispatched by designated personnel to ensure the reasonable allocation of small agricultural transport vehicles, small dump trucks, small excavators, and other machinery, and to avoid overloading or duplicate operations.
[0022] Construction material preparation includes sand, steel plates, gravel, and edge stake markings, etc.
[0023] 2. Temporary passageway layout Temporary work access roads were laid in the construction front area, with steel plates measuring 1.5m × 6m, a main road width of 6m, and a branch road width of 3m.
[0024] The steel plates on the main road should be laid in a staggered pattern along the direction of the machinery's movement, and should not be laid in the opposite direction. If the site's bearing capacity is insufficient, crushed stone can be laid on the sand cushion layer first, and then the steel plates can be placed on top.
[0025] Once the temporary access roads are set up, ensure that construction machinery can pass safely and form a "T" shape or multiple branch road intersections to support cyclical construction.
[0026] 3. Sand cushion layer thickness control Side stakes are laid out within a 10×10m range on the construction site, and the side stakes are marked with red paint at a distance of 0.7m from the ground surface to control the thickness of the sand cushion layer.
[0027] During the sand laying process, the elevation of the subgrade is adjusted based on real-time monitoring data to ensure uniform sand thickness and to form a drainage slope, ensuring that rainwater drains naturally from the site and preventing water accumulation.
[0028] 4. Retreating sand paving and phased construction like Figure 2 As shown, the sand-laying operation adopts the backward sand-laying method, that is, the construction machinery always operates on the completed sand cushion layer and gradually moves backward to avoid the machinery directly acting on the weak foundation.
[0029] The construction phased implementation steps are as follows: Construction on Branch Road 1: Transport vehicles travel along the main road and the steel plate channel of the branch road to the end of the branch road to unload sand; the single transport volume is controlled between 1.0 and 3.0 m³ according to the type of machinery, of which small agricultural transport vehicles should be controlled between 1.0 and 1.5 m³, and small dump trucks should be controlled between 2.0 and 3.0 m³; after unloading sand, it is spread by small excavators or manual labor, and the initial leveling thickness is 5 to 10 cm higher than the design thickness; the backward sand spreading method is adopted, and the machinery always operates on the already laid sand cushion layer or steel plate channel, and it is strictly forbidden to walk or turn directly on the original silt surface; Construction on both sides of Branch Road 1: After the sand cushion layer of branch road 1 forms a stable working zone, sand cushion layers are laid in adjacent areas on both sides with branch road as the center. During construction, the thickness of the sand cushion layer is controlled by side stakes, with a density of one side stake every 10-20 square meters, and the marking height corresponds to the design top elevation of the sand cushion layer. After the sand cushion layer is laid, it is leveled in time and a 0.3%-0.5% slope is formed to ensure smooth drainage.
[0030] 5. Construction Safety and Quality Control The steel plates and branch road layout are uniformly scheduled by designated personnel to ensure that construction machinery always operates on a solid working surface; after each day's work is completed, the working surface is leveled in a timely manner, and the elevation and thickness of the sand cushion layer are checked to ensure that they meet the design requirements; construction machinery is operated in accordance with safety regulations, and overloading or high-speed driving is strictly prohibited to prevent damage to the soft foundation.
[0031] 6. Improved efficiency of cyclical operations and construction By alternating the placement of branch roads and steel plates, cyclical operations are achieved, ensuring that construction machinery always operates on a solid working surface. This segmented advancement and cyclical deployment method guarantees orderly, safe, and efficient construction, and is suitable for sand cushion layer construction in large areas of soft soil foundations and silt-backfilled areas.
Claims
1. A construction method for zonal reinforcement and bearing capacity enhancement of large-area soft soil foundations, characterized in that: The construction method includes: S1. Before construction, based on the construction area, foundation bearing capacity test results, and sand cushion layer design thickness, the foundation of the construction site is divided into zones. A T-shaped main road is prioritized along the length of the construction area as a temporary passage for construction machinery. This T-shaped main road consists of a longitudinal main road and a transverse distribution road. The main road is paved using a composite method of crushed stone leveling and steel plate laying, laid in a staggered pattern along the direction of machinery travel, with an overlap length of not less than 30cm. Several branch roads are laid sequentially on both sides of the transverse distribution road. The steel plate laying method and structure of the branch roads are consistent with the main road, used for subsequent segmented sand paving construction. The longitudinal main road is 5–8m wide, and the transverse distribution road is 4–6m wide. Sand is transported to the construction area mechanically to ensure that construction machinery operates on a solid working surface to complete the sand cushion layer laying. The crushed stone particle size is 20–40mm, the thickness is not less than 20cm, and the steel plate specifications are 1.2–2.0m × 6-8m; On both sides of the transverse distribution channel, several branch roads are laid out in sequence at intervals of 10-20m, and the width of the branch roads is controlled at 2-4m; Before laying the sand cushion layer, side stakes are laid out in the construction site every 10-20m² to control the thickness of the cushion layer, and the side stakes are marked at a certain height in order to monitor the thickness of the sand cushion layer. S2. Construction machinery enters the transverse distribution channel via the inverted T-shaped main road, prioritizing the outermost branch road 1 as the first working surface for sand cushion layer construction; the branch road sand cushion layer construction adopts the method of constructing the branch road first, then the two sides; the specific operation is as follows: Construction on S21 and Branch Road 1: Transport vehicles travel along the main road and the steel plate channel of the branch road to the end of the branch road to unload sand; the single transport volume is controlled between 1.0 and 3.0 m³ according to the type of machinery, of which small agricultural transport vehicles should be controlled between 1.0 and 1.5 m³, and small dump trucks should be controlled between 2.0 and 3.0 m³; after unloading sand, it is spread by small excavators or manual labor, and the initial leveling thickness is 5 to 10 cm higher than the design thickness; the backward sand spreading method is adopted, and the machinery always operates on the already laid sand cushion layer or steel plate channel, and it is strictly forbidden to walk or turn directly on the original silt surface; Construction on both sides of S22 and Branch Road 1: After the sand cushion layer of branch road 1 forms a stable working zone, sand cushion layers are laid in adjacent areas on both sides with branch road as the center. During construction, the thickness of the sand cushion layer is controlled by side stakes, with a density of one stake every 10-20 square meters. The height of the stakes corresponds to the top elevation of the designed sand cushion layer. After the sand cushion layer is laid, it is leveled in time and a 0.3%-0.5% slope is formed to ensure smooth drainage. S3. After the sand cushion layer is laid in branch road 1 and the corresponding construction areas on both sides, the construction machinery will advance in the following order: the steel plate channel will be laid in branch road 2 during the construction of branch road 1, but sand will not be laid immediately; after the completion of branch road 1, the construction machinery will be transferred to branch road 2 through the transverse distribution channel, and the sand cushion layer and the construction of the areas on both sides of branch road 2 will be completed in the same way as branch road 1; after the construction of branch road 2 is completed and a stable working surface is formed, the steel plates in the area of branch road 1 will be removed section by section and transferred to branch road 3. S4. Following the method of laying sand in front and removing slabs behind, complete the subsequent construction sections such as branch road 3 and branch road 4 in sequence until the sand cushion layer of the entire construction area is laid.
2. The construction method for zonal reinforcement and bearing capacity enhancement of large-area soft soil foundation according to claim 1, characterized in that: The sand includes medium-coarse sand, fine sand, or a mixture thereof. The construction machinery includes small agricultural transport vehicles, small dump trucks, and small excavators. The single transport volume is 1.0 to 3.0 m³, which is adjusted according to the type of machinery and the bearing capacity of the construction surface.
3. The construction method for zonal reinforcement and bearing capacity enhancement of large-area soft soil foundation according to claim 1, characterized in that: The construction method described herein is applicable to the construction of sand cushion layers in large areas of soft soil foundations, silt backfill areas, and other low-bearing-capacity sites. The width of the passage, the thickness of the sand, and the type of machinery can be flexibly adjusted according to the site conditions.