Foundation treatment structure and methods under stockpiles

Abstract

This invention relates to a foundation treatment structure and method under a stockpiled material foundation. The foundation treatment structure includes: multiple piles, installed in the foundation with variable stiffness according to the load gradient of the upper stockpiled material; a frame beam connected to the top of the multiple piles; a cushion layer disposed above the frame beam; multiple drainage ditches, arranged parallel and spaced above the cushion layer, with the centerline of the drainage ditches aligned vertically with the centerline of a row of piles located below them; slots provided on the sidewalls of the drainage ditches; multiple prefabricated arched walls, the bottom ends of which are inserted into corresponding slots, with the length direction of the prefabricated arched walls being the same as the extension direction of the drainage ditches; and a backfill layer filling the outer perimeter space of each prefabricated arched wall. This invention solves the problems of easy cracking and deformation of cast-in-place raft slabs, large pile usage and easy puncture, long construction period, large uneven settlement, and easy groundwater pollution in existing foundation treatment structures under stockpiled materials.

Description

Technical Field

[0001] This invention relates to the field of foundation treatment, and more particularly to a foundation treatment structure and method under stockpiled materials. Background Technology

[0002] Foundation treatment under large-area material stockpiles is a key technology in industrial and port engineering, mainly applied to large stockpiles of coal, ore, and building materials, as well as port terminals, power plant ash storage yards, and chemical raw material stockpiles. For soft foundations such as thick backfill, silt, silty soil, and soft plastic to fluid plastic clay, foundation treatment under large-area material stockpiles generally adopts CFG piles + sand and gravel cushion layer + large-area raft foundation to ensure the stability of the foundation under the material stockpiles.

[0003] Existing technologies such as Figure 1 and Figure 2 As shown: The existing method for treating the soft soil under the large-area stockpile 04 is to use CFG piles or other rigid shapes in a rectangular or staggered arrangement, then lay a sand and gravel cushion layer 02 of a certain thickness on top of the piles 01, and finally place a reinforced concrete raft slab 03 on top.

[0004] However, existing technologies have the following drawbacks: (1) The cast-in-place reinforced concrete raft slab is relatively thick and often cracks and deforms under a large amount of material, which makes it inconvenient to stack and retrieve materials.

[0005] (2) A large number of piles are used, and they need to be evenly arranged at a certain interval. Heavy piles of material are prone to puncture.

[0006] (3) The construction period is long due to the cast-in-place concrete raft foundation. Summary of the Invention

[0007] The purpose of this invention is to provide a foundation treatment structure and method under stockpiled materials, which solves the problems of easy cracking and deformation of cast-in-place raft slabs, large amount of piles that are easy to be punctured, long construction period, large uneven settlement, and easy pollution of groundwater in existing foundation treatment structures under stockpiled materials.

[0008] The objective of this invention can be achieved using the following technical solutions: This invention provides a foundation treatment structure under a stockpile, comprising: multiple piles, which are set in the foundation with variable stiffness according to the load gradient of the upper stockpile; a frame beam connected to the top of the multiple piles; a mattress layer set above the frame beam; multiple drainage ditches, which are set parallel and spaced above the mattress layer, and the center line of the drainage ditches is aligned vertically with the center line of a row of piles located below them; the side walls of the drainage ditches are provided with slots; multiple prefabricated arc-shaped arch walls, the bottom ends of the prefabricated arc-shaped arch walls are inserted into the corresponding slots, and the length direction of the prefabricated arc-shaped arch walls is the same as the extension direction of the drainage ditches; and a backfill layer filling the outer periphery of each prefabricated arc-shaped arch wall.

[0009] In a preferred embodiment of the present invention, the variable stiffness is achieved by decreasing the pile spacing as the material load increases, and / or increasing the pile length as the material load increases.

[0010] In a preferred embodiment of the present invention, the frame beam includes a plurality of horizontal beams and a plurality of vertical beams arranged in a crisscross pattern, wherein the length direction of the horizontal beams is perpendicular to the length direction of the precast arched wall.

[0011] In a preferred embodiment of the present invention, the precast arc-shaped arch wall is a precast reinforced concrete component, and is composed of multiple segments spliced ​​together along the length of the drainage ditch.

[0012] In a preferred embodiment of the present invention, the cross-section of the prefabricated arc-shaped arch wall is circular arc-shaped, and the central angle of the circular arc is less than 180°, equal to 180°, or greater than 180°.

[0013] In a preferred embodiment of the present invention, a grouting material filling layer is provided between the bottom outer wall of the prefabricated arc-shaped arch wall and the side wall of the slot.

[0014] In a preferred embodiment of the present invention, the plurality of drainage ditches include two side drainage ditches located at the two sides of the mattress layer and at least one intermediate drainage ditch located in the middle; the outer side wall of the side drainage ditch extends upward to form a side plate, and the inner side wall of the side drainage ditch is provided with a slot; the two side walls of the intermediate drainage ditch are provided with two slots; a filling area is formed between the side plate, the side drainage ditch, the intermediate drainage ditch and the outer peripheral space of each prefabricated arc-shaped arch wall, and the backfill layer fills the filling area.

[0015] In a preferred embodiment of the present invention, the backfill layer is a compacted sand and gravel backfill layer.

[0016] In a preferred embodiment of the present invention, the pile is a CFG pile, a reinforced concrete cast-in-place pile, a prestressed pipe pile, or a steel pipe pile; the frame beam is a reinforced concrete beam or a steel structure beam.

[0017] The present invention also provides a foundation treatment method under a stockpile, comprising: setting multiple piles in the foundation in a variable stiffness manner according to the load gradient of the upper stockpile; constructing a frame beam on top of the multiple piles to connect the frame beam to the piles; laying a mattress layer on top of the frame beam; constructing multiple drainage ditches on top of the mattress layer, aligning the center line of the drainage ditches vertically with the center line of a row of piles located below them, and setting slots on the side walls of the drainage ditches; hoisting multiple prefabricated arch walls respectively, inserting the bottom end of the prefabricated arch walls into the corresponding slots, and aligning the length direction of the arch walls with the extension direction of the drainage ditches; filling the outer periphery of each prefabricated arch wall with backfill material and compacting it.

[0018] As described above, this invention saves on the number of piles by using variable stiffness piles, utilizes prefabricated arched walls to replace traditional cast-in-place raft slabs to achieve arch effect force transmission, enhances the integrity of the pile body and the soil constraint between piles by using frame beams, and achieves drainage and pollution prevention through drainage ditches. Overall, it achieves the comprehensive effects of saving materials, shortening the construction period, improving bearing capacity, reducing settlement, and preventing pollution. Attached Figure Description

[0019] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the invention. Wherein: Figure 1 This is a schematic diagram of the foundation treatment for large-area material stockpiling using existing technologies.

[0020] Figure 2 This is a cross-sectional schematic diagram of the foundation treatment under large-area material stockpiling using existing technologies.

[0021] Figure 3 This is a plan view of the foundation treatment structure under the stockpile provided by the present invention.

[0022] Figure 4 This is a cross-sectional schematic diagram of the foundation treatment structure under the stockpile provided by the present invention.

[0023] Figure 5 for Figure 4 A magnified view of a portion of the image.

[0024] Explanation of icon numbers: Existing technology: 01. Piles; 02. Sand and gravel cushion layer; 03. Reinforced concrete raft slab; 04. Material stockpile.

[0025] This invention: 1. Piles; 2. Frame beam; 21. Horizontal beam; 22. Longitudinal beam; 3. Mattress padding layer; 4. Drainage ditch; 41. Edge drainage ditch; 411. Side panel; 42. Middle drainage ditch; 5. Slots; 6. Precast arched wall; 61. Grouting filler layer; 7. Backfill layer; 8. Material pile. Detailed Implementation

[0026] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0027] like Figures 3 to 5 As shown, this application provides a foundation treatment structure under a stockpile, comprising: Multiple piles 1 are installed in the foundation with variable stiffness according to the load gradient of the superstructure material; Frame beam 2 is connected to the top of multiple piles 1; The mattress layer 3 is placed above the frame beam 2; Multiple drainage ditches 4 are arranged in parallel at intervals above the mattress layer 3, and the center line of the drainage ditch 4 is aligned vertically with the center line of a row of piles 1 located below it; the side wall of the drainage ditch 4 is provided with slots 5; Multiple prefabricated arc-shaped arch walls 6, the bottom end of the prefabricated arc-shaped arch walls 6 is inserted into the corresponding slots 5, and the length direction of the prefabricated arc-shaped arch walls 6 is the same as the extension direction of the drainage ditch 4. Backfill layer 7 fills the outer perimeter space of each prefabricated arched wall 6.

[0028] Therefore, this application achieves the comprehensive effects of saving materials, shortening the construction period, improving bearing capacity, reducing settlement, and preventing pollution by using variable stiffness piles, replacing traditional cast-in-place raft slabs with precast arched walls 6, enhancing the integrity of the pile body and the soil constraint between piles with frame beams 2, and achieving drainage and pollution prevention through drainage ditches 4.

[0029] Furthermore, the variable stiffness is achieved by decreasing the pile spacing as the material load increases, and / or increasing the pile length as the material load increases.

[0030] In the specific design, the foundation is divided into multiple zones with different loads based on the distribution of the material load. In zones with higher loads, the pile spacing is smaller than in zones with lower loads, and / or, the pile length is longer in zones with higher loads than in zones with lower loads. This scheme, with its refined pile layout based on load distribution, can further reduce the number of piles required.

[0031] Further optional, see Figure 1 and Figure 2 The frame beam 2 includes multiple crossbeams 21, the length direction of which is perpendicular to the length direction of the precast arched wall 6, in order to improve the stability of the precast arched wall 6.

[0032] Alternatively, the frame beam 2 may also include multiple longitudinal beams 22, with the multiple transverse and multiple longitudinal beams 22 arranged in a staggered pattern, and the length direction of the longitudinal beams 22 being parallel to the length direction of the precast arched wall 6.

[0033] The piles are connected by crisscrossing frame beams 2, forming a stable grid-like constraint system, which effectively prevents the precast arched wall 6 from shifting laterally under horizontal load, ensuring the integrity of the pile body and improving the constraint on the soil between the piles.

[0034] Alternatively, the frame beam 2 can be integrally cast and connected to the top of the multiple piles 1, or fixedly connected by pre-embedded connectors.

[0035] Alternatively, the precast arched wall 6 can be made of reinforced concrete and is composed of multiple segments spliced ​​together along the length of the drainage ditch 4. This facilitates factory production and rapid on-site installation, significantly shortening the construction cycle.

[0036] The cross-section of the aforementioned precast curved arch wall 6 is circular, and the central angle of this circular arc is less than 180°, equal to 180°, or greater than 180°. The specific arc shape of the arch wall can be flexibly selected according to specific load conditions and site requirements.

[0037] Furthermore, multiple piles 1 are only installed below the two ends of the corresponding precast arch wall 6. The span (i.e., its width) of the precast arch wall 6 matches the spacing between the two adjacent drainage ditches 4 (i.e., the two drainage ditches 4 below the two ends of the arch wall), and the height of the precast arch wall 6 is positively correlated with the span.

[0038] Further optional, see Figure 2 and Figure 3 A grouting material filling layer 61 is provided between the bottom outer wall of the precast arched wall 6 and the side wall of the slot 5. This grouting material filling layer 61 can be formed by filling with high-strength grouting material, which is used to firmly fix the arched wall to the drainage ditch 4, and at the same time seals the internal space of the precast arched wall 6 to prevent water from seeping in.

[0039] Furthermore, the aforementioned mattress layer 3 is laid horizontally, and the multiple drainage ditches 4 are arranged at intervals along the horizontal direction. The aforementioned multiple piles 1 can be divided into multiple rows of piles 1 arranged at horizontal intervals, with each row of piles 1 including multiple piles 1. The total number of multiple drainage ditches 4 is the same as the total number of rows of piles 1, and the center line of each drainage ditch 4 is aligned vertically with the center line of the multiple piles 1 contained in the corresponding row of piles 1.

[0040] To facilitate the backfilling of backfill layer 7, refer to Figure 2 and Figure 3 Multiple drainage ditches 4 include two side drainage ditches 41 located at both sides of the mattress layer 3 and at least one intermediate drainage ditch 42 located in the middle; the outer side wall of the side drainage ditch 41 extends upward to form a side plate 411, and the inner side wall of the side drainage ditch 41 is provided with a slot 5; the two side walls of the intermediate drainage ditch 42 are provided with two slots 5; a filling area is formed between the side plate 411, the side drainage ditch 41, the intermediate drainage ditch 42 and the outer peripheral space of each prefabricated arc-shaped arch wall 6 (the outer peripheral space includes the area around the side of the arc-shaped arch wall and the area above the top surface), and the backfill layer 7 fills the filling area.

[0041] The height of backfill layer 7 should be higher than the height of the highest precast arch wall 6 to form a continuous filling area and ensure the overall uniformity of stress. Optionally, backfill layer 7 is a sand and gravel backfill compaction layer. Sand and gravel materials have good permeability and compaction performance, which can effectively transfer the upper load and ensure smooth drainage.

[0042] Alternatively, pile 1 can be a CFG pile, a reinforced concrete cast-in-place pile, a prestressed pipe pile, or a steel pipe pile. The specific type can be determined based on site conditions, bearing capacity requirements, and project cost.

[0043] Alternatively, the frame beam 2 can be a reinforced concrete beam or a steel structure beam.

[0044] Furthermore, this application also provides a method for foundation treatment under stockpiles, comprising: Based on the load gradient of the upper material pile, multiple piles 1 are set in the foundation in a variable stiffness manner; Construct a frame beam 2 on top of multiple piles 1, so that the frame beam 2 is connected to the piles 1; A mattress layer 3 is laid on top of the frame beam 2; Multiple drainage ditches 4 are constructed above the mattress layer 3, with the center line of the drainage ditch 4 aligned vertically with the center line of a row of piles 1 located below it, and slots 5 are provided on the side wall of the drainage ditch 4. Multiple prefabricated arched walls 6 are hoisted separately, so that the bottom end of the prefabricated arched wall 6 is inserted into the corresponding slot 5, and the length direction of the arched wall is consistent with the extension direction of the drainage ditch 4. Fill the outer periphery of each precast curved arch wall 6 with backfill material and compact it.

[0045] This method can be achieved using the aforementioned foundation treatment structure under the stockpile, which saves on the amount of pile 1 and reinforced concrete, shortens the construction period, and prevents pollution of groundwater.

[0046] More specifically, the following is a detailed description of the foundation treatment process for the stockpile, including the following steps: Step 1: Variable stiffness pile installation. In soft soil, rigid piles are driven in a variable stiffness manner (e.g., variable spacing and / or variable length) according to the load gradient of the superstructure material.

[0047] The foundation in question is relatively uniform. The phrase "adjusting the pile spacing according to the load gradient of the superstructure" refers to a non-uniform pile arrangement, where the pile layout parameters are adjusted based on the load magnitude at different locations within the material pile area. Specifically, in areas with relatively high loads (such as directly below the center of the material pile 8), the pile spacing is smaller and the pile length is longer; in areas with relatively low loads (such as below the edge of the material pile 8), the pile spacing is larger and the pile length is shorter. The pile spacing decreases as the load increases, while the pile length increases.

[0048] Step 2: Construction of frame beam 2. Interlocking frame beams 2 are used for connection to ensure the integrity of the pile body and improve the constraint on the soil between the piles.

[0049] Step 3: Lay the mattress layer 3. Set a sand and gravel mattress layer of a certain thickness (e.g., 300-500mm thick) on top of the longitudinal and transverse frame beams 2, and achieve the compaction degree required by the specifications.

[0050] Step 4: Construct drainage ditch 4 and slot 5. Construct drainage ditch 4 on mattress layer 3, and provide slot 5 on the side wall of drainage ditch 4, requiring the center of drainage ditch 4 to correspond to the position of pile 1.

[0051] The drainage ditch 4 serves two purposes: firstly, it collects and drains seepage water from the material pile 8 to prevent water from seeping into and polluting the groundwater; secondly, the slots 5 on its side walls act as the mounting base for the prefabricated arched wall 6, providing positioning and load-bearing functions.

[0052] Step 5: Hoisting the prefabricated arched wall 6. Transport the prefabricated arched walls from the factory to the site, and use hoisting equipment to lift them so that the bottom end of the prefabricated arched wall 6 is inserted into the slot 5 on the side wall of the drainage ditch 4.

[0053] Step 6: Grouting and fixing. High-strength grout is injected between the bottom outer wall of the precast arched wall 6 and the side wall of the slot 5 to form a grout filling layer 61.

[0054] Step 7: Backfill the space around the precast arched wall 6 with sand and gravel and compact it to form the backfill layer 7.

[0055] The backfill layer 7 wraps the top and outside of each precast arch wall 6, forming an integrated load-bearing system, so that the load is evenly transferred to the arch wall and pile below; the high permeability of the sand and gravel material in the backfill layer 7 ensures that seepage water can smoothly enter the drainage ditch 4; the compacted backfill layer 7 has sufficient bearing capacity and can directly bear the load of the stockpiled material.

[0056] During the entire structure's operation, the load from the stockpiled material initially acts on the top of the backfill layer 7 and the precast arched wall 6. The arched wall utilizes the arch effect to convert the vertical load into compressive stress along the arch axis, which is then transferred to the slots 5 at both ends of the arch wall and subsequently to the piles below via the drainage ditch 4. In areas with higher loads, the piles are spaced closer together and longer, providing greater bearing capacity; in areas with lower loads, the piles are spaced further apart and shorter, avoiding material waste. The frame beam 2 connects the individual piles into a whole, effectively constraining the lateral deformation of the soil between the piles, improving the overall bearing capacity and deformation resistance of the composite foundation, and reducing uneven settlement. Simultaneously, seepage water from the stockpile 8 permeates through the backfill layer 7 and the cushion layer 3, flowing into the drainage ditch 4 and being discharged from the treatment area along the ditch 4, preventing contaminated water from seeping into and polluting the groundwater. In the entire structural system, pile 1 bears the main vertical load, precast arched wall 6 achieves efficient load transfer, frame beam 2 ensures overall stability, drainage ditch 4 achieves pollution control, and all components work together to meet the bearing capacity, deformation and environmental protection requirements of soft foundation under large-area material stockpiling.

[0057] In summary, the foundation treatment structure and method under material stockpiling in this application are particularly suitable for large areas. It represents a variable stiffness foundation treatment method for effectively transferring forces under large-area material stockpiling, and is a treatment approach for weak foundations under large-area material stockpiling. Specifically, the effects are as follows: (1) Pile positions are arranged with varying stiffness according to the load gradient, saving the amount of piles used.

[0058] (2) Precast arched walls 6 are used to replace traditional thick raft slabs, making full use of the high compressive strength of concrete and the high force transmission efficiency of the arch effect, effectively transmitting pressure and saving concrete usage.

[0059] (3) The prefabricated arc-shaped arch wall 6 is prefabricated in sections and hoisted for installation, which saves construction time.

[0060] (4) The piles are connected by a crisscrossing frame beam 2 to ensure overall stress, strengthen the constraint of the soil between the piles, improve the bearing capacity of the composite foundation, ensure the uniformity of the bearing capacity of the pile-soil composite foundation, and reduce uneven settlement.

[0061] (5) Drainage ditches 4 are set between the precast arched walls 6, which can effectively collect the water in the material pile 8 and prevent pollution of groundwater.

[0062] (6) A grouting material filling layer 61 is set between the bottom of the arc-shaped arch wall and the slot 5 to achieve fixation and sealing. The side drainage ditch 41 is equipped with side plates 411 to form an overall filling area to ensure the stability of the structure under various loads.

[0063] The above are merely illustrative embodiments of the present invention and are not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A foundation treatment structure under a stockpile, characterized in that, include: Multiple piles are installed in the foundation with varying stiffness according to the load gradient of the superstructure material; A frame beam is connected to the top of multiple piles; A mattress layer is placed above the frame beam; Multiple drainage ditches are arranged parallel to each other above the mattress layer, and the center line of each drainage ditch is aligned vertically with the center line of a row of piles located below it; the sidewalls of the drainage ditches are provided with slots; Multiple prefabricated arc-shaped arch walls, the bottom ends of which are inserted into corresponding slots, and the length direction of the prefabricated arc-shaped arch walls is the same as the extension direction of the drainage ditch; The backfill layer fills the outer periphery of each of the prefabricated arched walls.

2. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, The variable stiffness is achieved by decreasing the pile spacing as the material load increases, and / or increasing the pile length as the material load increases.

3. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, The frame beam includes multiple horizontal beams and multiple vertical beams arranged in a crisscross pattern, with the length direction of the horizontal beams perpendicular to the length direction of the precast arched wall.

4. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, The precast arched wall is a precast reinforced concrete component, and is composed of multiple segments spliced ​​together along the length of the drainage ditch.

5. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, The cross-section of the prefabricated arc-shaped arch wall is circular, and the central angle of the circular arc is less than 180°, equal to 180°, or greater than 180°.

6. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, A grouting material filling layer is provided between the bottom outer wall of the prefabricated arc-shaped arch wall and the side wall of the slot.

7. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, The plurality of drainage ditches include two side drainage ditches located at the two sides of the mattress layer and at least one intermediate drainage ditches located in the middle; The outer wall of the side drainage ditch extends upward to form a side plate, and the inner wall of the side drainage ditch is provided with one of the slots; the two side walls of the middle drainage ditch are provided with two of the slots. A filling area is formed between the side panels, the edge drainage ditch, the middle drainage ditch, and the outer peripheral space of each of the prefabricated arc-shaped arch walls, and the backfill layer fills the filling area.

8. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, The backfill layer is a compacted sand and gravel backfill layer.

9. The foundation treatment structure under the stockpile as described in claim 1, characterized in that, The piles are CFG piles, reinforced concrete cast-in-place piles, prestressed pipe piles, or steel pipe piles; the frame beams are reinforced concrete beams or steel structure beams.

10. A method for foundation treatment under stockpiles, characterized in that, include: Based on the load gradient of the upper material pile, multiple piles are set in the foundation in a variable stiffness manner; Construct a frame beam on top of the piles, connecting the frame beam to the piles; A mattress layer is laid on top of the frame beam; Multiple drainage ditches are constructed above the mattress layer, with the center line of the drainage ditches aligned vertically with the center line of a row of piles located below them, and slots are provided on the sidewalls of the drainage ditches. Multiple prefabricated arched walls are hoisted separately, so that the bottom end of the prefabricated arched wall is inserted into the corresponding slot, and the length direction of the arched wall is consistent with the extension direction of the drainage ditch. Backfill material is filled into the outer periphery of each of the prefabricated arched walls and compacted.

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