Construction method of roadbed under adverse geological conditions

Abstract

The application discloses a kind of bad geological conditions subgrade construction method, comprising: step one, cleaning surface sundries, excavating soft soil foundation;Step two, paving stone, compaction, filling backfill, compaction, form base layer;Step three, paving geotextile, paving graded crushed stone, compaction, install anti-settling structure, fill graded crushed stone again until cover anti-settling structure, compaction, form anti-settling layer;Anti-settling structure includes: underframe, it is spherical, opening upward;Multiple support columns, bottom limit activity is set on underframe;Top cover, it includes multiple top frames that are sequentially limited to each other along the transverse direction of subgrade, it is spherical, opening downward, top frame limit activity cover connection on support column top, top cover is along the transverse direction of subgrade The shape of middle high and both sides low;Step four, paving geotextile;Step five, pouring concrete;Step six, paving asphalt concrete, compaction, form pavement.The application has the beneficial effect of preventing pavement settlement under bad geological conditions.

Description

Technical Field

[0001] This invention relates to the field of road construction technology. More specifically, this invention relates to a method for constructing roadbeds under adverse geological conditions. Background Technology

[0002] Unfavorable geological conditions, also known as soft soil foundations, refer to soils with high water content, primarily composed of loose, natural soil particles. This type of soil is common in most parts of my country, especially in some coastal areas of the south, where many areas have soft plastic or fluid plastic clayey soils. During highway construction, relevant personnel must take targeted measures and methods based on the actual conditions to effectively treat soft soil subgrades, thereby improving their stability and preventing problems in subsequent construction. Soft foundations reduce the stability and safety of regional construction, affecting the normal operation of highway projects. Soft soil foundation areas have low safety; if landslides occur, the structure of the soft soil foundation becomes more dispersed, leading to the inability to operate the highway project normally. If the soft soil foundation is not reinforced, it will settle over time, and heavy rains and the rainy season will exacerbate this settlement, increasing resource depletion.

[0003] Currently, common treatment methods for soft soil foundations include base reinforcement, soil replacement, lateral restraint, preloading consolidation, composite foundations, and soil stabilizer methods. However, the quality of treated soft soil foundation projects is often difficult to achieve ideal results, and post-construction settlement and vehicle bouncing are very serious problems in road sections treated with soft soil. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0005] To achieve these objectives and other advantages according to the present invention, a method for constructing roadbeds under adverse geological conditions is provided, comprising the following steps:

[0006] Step 1: Clear surface debris and excavate the soft soil foundation to the target baseline;

[0007] Step 2: Lay rubble on the base, compact it, then fill with backfill material, compact it, and form the base layer;

[0008] Step 3: Lay geotextile on the base layer to form the first geotextile layer, then lay graded crushed stone, compact it, then install the anti-settlement structure, and then fill it with graded crushed stone until it covers the top of the anti-settlement structure by at least 10cm, compact it, and form the anti-settlement layer.

[0009] The anti-settlement structure includes:

[0010] The base frame is spherical in shape, with its opening facing upwards;

[0011] Multiple support pillars, with their bottom limiters movably mounted on the base frame;

[0012] The top cover includes multiple top frames that are sequentially and mutually constrained and overlapped along the transverse direction of the roadbed. The top frames are spherical in shape and have their openings facing downwards. The top frames are movably and constrained to cover the top of the support column. The top cover has a shape that is high in the middle and low on both sides along the transverse direction of the roadbed.

[0013] Step 4: Lay geotextile on the anti-settlement layer to form a second geotextile layer;

[0014] Step 5: Pour concrete onto the second geotextile layer to form a concrete layer;

[0015] Step 6: Lay asphalt concrete on the concrete layer, compact it, and form the road surface.

[0016] Preferably, in step two, the paving stones are laid in layers and the backfill material is filled, with each layer having a thickness of 50-100mm. After compaction, the next layer is laid and filled.

[0017] Preferably, the base frame in step three includes a pair of side bones arranged opposite each other, a pair of arc-shaped bones connected to the two ends of the pair of side bones, and an arc-shaped reinforcing bone fixed at both ends between the pair of side bones. The arc-shaped bones are provided with a plurality of elongated limiting grooves along the transverse direction of the roadbed, and the bottom of the support column is movably abutted against the limiting grooves.

[0018] Preferably, the support column in step three includes an arc-shaped base plate that movably abuts against the limiting groove, a support rod whose bottom is fixed to the base plate, and a connecting ball fixed to the top of the support rod, wherein the connecting ball is limited to move on the top frame.

[0019] Preferably, the top frame in step three includes a pair of oppositely arranged side edges, a pair of arc-shaped load-bearing plates connected to the two ends of the pair of side edges, and arc-shaped reinforcing ribs fixed at both ends between the pair of side edges. The load-bearing plates are provided with spherical receiving grooves, and the connecting ball is movably received in the receiving grooves.

[0020] Preferably, the side edges in step three are made of channel steel, and the side edges of two adjacent top frames are movably interlocked.

[0021] Preferably, in step three, multiple quicklime blocks are laid between the base frame and each top frame. The quicklime blocks are made of breathable, long, flexible bags filled with quicklime.

[0022] Preferably, the thickness of the quicklime block in step three is 10–20 cm.

[0023] The present invention has at least the following beneficial effects:

[0024] First, the top cover has a structure that converges towards the center and opens downwards, forming a coordinated structure with the base frame. The top frame itself also has an opening facing downwards and converges towards the center. The top of the support column has 360° of free movement relative to the top frame to distribute the pressure transmitted from above. When the anti-settlement structure is subjected to pressure from the roadbed above, the top cover, support columns, and base frame cause relative displacement of the surrounding graded crushed stone. However, when the pressure disappears, the convergence of the top cover and base frame allows the relative displacement to automatically return to its original equilibrium position, achieving the technical effect of anti-settlement.

[0025] Secondly, the first and second geotextile layers serve to isolate the base layer from the anti-settlement layer, and also from the concrete layer, preventing the loss of soil particles, fine sand, and small stones within the anti-settlement layer, thus maintaining the stability of the roadbed. Additionally, the first and second geotextile layers also have a drainage function, possessing excellent water conductivity and creating drainage channels within the soil to discharge excess liquid and gas from the soil structure laterally into the roadbed.

[0026] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0027] Figure 1 This is a side sectional view of the roadbed according to one of the technical solutions of the present invention;

[0028] Figure 2 This is a top view of the base frame according to one of the technical solutions of the present invention;

[0029] Figure 3 This is a bottom view of the top frame according to one of the technical solutions of the present invention;

[0030] Figure 4 This is a detailed view of the support column according to one technical solution of the present invention;

[0031] Figure 5 This is a schematic diagram showing the connection of the side edges of two adjacent top frames in one of the technical solutions of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0033] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the orientation or positional relationship indicated by the terms is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0034] like Figures 1-5 As shown in the accompanying drawings of this invention, the reference numerals are interpreted as follows: base layer 100, first geotextile layer 200, anti-settlement layer 300, base frame 1, support column 2, top frame 3, anti-settlement structure 700, second geotextile layer 400, concrete layer 500, road surface 600, side rib 11, arc-shaped rib 12, reinforcing rib 13, limiting groove 14, bottom plate 21, support rod 22, connecting ball 23, side edge 31, bearing plate 32, reinforcing bar 33, receiving groove 34, quicklime block 4.

[0035] like Figures 1-5 As shown, the present invention provides a method for roadbed construction under adverse geological conditions, comprising the following steps:

[0036] Step 1: Clear surface debris and excavate to the target baseline; use the excavation and replacement method to treat the soft soil foundation. Through preliminary on-site survey, set the target baseline for the soft soil foundation, and then excavate the soft soil foundation directly until the target baseline position is reached, and level the base surface.

[0037] Step 2: Lay rubble stones on the base, compact them, then fill with backfill material and compact again to form a 100mm base layer. Use rubble stones larger than 30cm in size to lay on the base, laying one layer at a time, each layer 50-100mm thick. Then, use a road roller to compact it, selecting multiple testing locations to test the foundation bearing capacity, usually three locations. Once the foundation bearing capacity meets the requirements of the road to be built, for example, 120kPa for ordinary roads and 150kPa for expressways, fill with backfill material, filling the gaps between the rubble stones and raising it about 20cm above the rubble stones. Compact it until the foundation bearing capacity reaches the preset standard. The backfill material can be prepared by uniformly mixing 5% bentonite, 10% water-reducing agent, 10% cement, 5% fly ash, 25% quartz sand, and 45% water by weight. Repeat the above steps of laying rubble stones and filling with backfill material until the paving thickness reaches the preset height.

[0038] Step 3: Lay geotextile on the base layer 100 to form the first geotextile layer 200, then lay graded crushed stone, compact it, then install the anti-settlement structure 700, and then fill it with graded crushed stone until it covers the top of the anti-settlement structure 700 by at least 10cm, compact it, and form the anti-settlement layer 300. The graded crushed stone is a mixture of coarse and fine crushed stone aggregates and stone chips in a certain proportion, and its particle composition meets the requirements of dense gradation. First, lay 15-30cm of graded crushed stone on the base layer 100, then use a road roller to compact it until the foundation bearing capacity reaches the preset standard. Then install the anti-settlement structure 700, and install the base frame 1, support column 2, and top cover in sequence from bottom to top. Then lay graded crushed stone until it covers the top cover by 10-30cm, and use a road roller to compact it until the foundation bearing capacity reaches the preset standard. The anti-settlement structure has a 700mm vertical downward projection that is square, with the side length slightly smaller than the transverse width of the roadbed, and a distance of 10-20cm is left on each side.

[0039] Furthermore, a layer of quicklime blocks 4 is laid evenly at intervals within the anti-settlement structure 700. Multiple quicklime blocks 4 are placed between the base frame 1 and each top frame 3. The quicklime blocks 4 are made of breathable, long, flexible bags filled with quicklime, such as cloth bags or woven bags. The size is preferably cuboid, with a length, width, and thickness of 60-100cm, 30-40cm, and 10-20cm, respectively. The quicklime blocks 4 do not contact the anti-settlement structure 700 but are contained within the graded crushed stone. By laying the quicklime blocks 4, the quicklime reacts with water to form solid calcium compounds, which expand in volume and can compensate for some of the soil loss and internal voids in the roadbed caused by water flow.

[0040] The anti-settlement structure 700 includes:

[0041] The base frame 1 is spherical in shape, with its opening facing upwards, forming a structure that converges towards the center.

[0042] Multiple support pillars 2 are movably mounted on the base frame 1 at their bottom limits; they are used to connect the base frame 1 and the top cover, and to transmit the interaction force between the base frame 1 and the top cover. The support pillars 2 have a movable space relative to the base frame 1 along the roadbed laterally.

[0043] The top cover comprises multiple top frames 3 that are sequentially and mutually constrained along the transverse direction of the roadbed. Each top frame 3 is spherical in shape with its opening facing downwards. The top frame 3 is movably attached to the top of the support column 2. The top cover has a shape that is higher in the middle and lower on both sides along the transverse direction of the roadbed. The top cover has a structure that converges towards the center with its opening facing downwards, forming an upper and lower mating structure with the base frame 1. The top frames 3 forming the top cover also have an opening facing downwards and converge towards the local center. The top of the support column 2 has 360° of free movement relative to the top frames 3 to distribute the pressure transmitted from the top. When the anti-settlement structure 700 is subjected to pressure from the roadbed above, the top cover, support column 2, and base frame 1 cause relative displacement of the surrounding graded crushed stone. However, when the pressure disappears, the convergence of the top cover and base frame 1 allows the relative displacement to automatically return to its original equilibrium position, achieving the technical effect of anti-settlement.

[0044] Furthermore, the base frame 1 includes a pair of oppositely arranged side ribs 11, a pair of arc-shaped ribs 12 connected to the two ends of the pair of side ribs 11, and arc-shaped reinforcing ribs 13 fixed at intervals between the pair of side ribs 11. The arc-shaped ribs 12 are provided with multiple elongated limiting grooves 14 spaced laterally along the roadbed, and the bottom of the support column 2 movably abuts against the limiting grooves 14. By using arc-shaped ribs 12 and reinforcing ribs 13 to form a near-spherical shape instead of steel plates, the amount of steel used is significantly reduced without affecting the central convergence effect, saving construction costs and not affecting the drainage function of the anti-settlement layer 300.

[0045] Furthermore, the support column 2 includes an arc-shaped base plate 21 that movably abuts within the limiting groove 14, a support rod 22 with its bottom fixed to the base plate 21, and a connecting ball 23 fixed to the top of the support rod 22. The connecting ball 23 is limited to move on the top frame 3. The base plate 21 can move laterally along the roadbed on the bottom frame 1, dispersing force. The connecting ball 23 has a 360° limiting and turning function, and, in conjunction with the base plate 21, has the function of lateral swaying and dispersing force along the roadbed.

[0046] Furthermore, the top frame 3 includes a pair of opposing side edges 31, a pair of arc-shaped load-bearing plates 32 connected to the two ends of the pair of side edges 31, and arc-shaped reinforcing ribs 33 fixed at intervals between the pair of side edges 31. The load-bearing plates 32 are provided with spherical receiving grooves 34, and the connecting ball 23 is movably accommodated within the receiving grooves 34. Similar to the design concept of the base frame 1, the side edges 31 and reinforcing ribs 33 are used to form a spherical shape instead of steel plates. This significantly reduces the amount of steel used without affecting the central convergence effect, saving construction costs, and does not affect the drainage function of the anti-settlement layer 300. The receiving grooves 34 provide multi-directional limiting functions for the connecting ball 23, preventing the support column 2 from deviating too far from the center.

[0047] Furthermore, the side edges 31 are made of channel steel, and the side edges 31 of two adjacent top frames 3 are movably interlocked. This facilitates the construction and installation of the top frames 3 and speeds up construction efficiency.

[0048] Step 4: Lay geotextile on the anti-settlement layer 300 to form the second geotextile layer 400. The first geotextile layer 200 and the second geotextile layer 400 serve to isolate the base layer 100 from the anti-settlement layer 300 and the concrete layer 500, preventing the loss of soil particles, fine sand, and small stones within the anti-settlement layer 300, thus maintaining the stability of the roadbed. In addition, the first geotextile layer 200 and the second geotextile layer 400 also have a drainage function, possessing good water conductivity, which can create drainage channels within the soil, discharging excess liquid and gas from the soil structure towards the lateral direction of the roadbed.

[0049] Step 5: Pour concrete onto the second geotextile layer 400 to form a concrete layer 500. Concrete is an artificial stone material made by mixing cementitious materials, aggregates, water, admixtures, and additives in a specific ratio, followed by uniform mixing, compaction, and curing. Concrete has high compressive strength, good durability, and a wide strength range, providing an excellent load-bearing foundation. The thickness of the concrete layer 500 is determined according to the highway grade.

[0050] Step Six: Lay asphalt concrete on the concrete layer 500 and compact it to form the road surface 600. Use a road roller to first compact both sides of the roadbed, then compact the middle part of the roadbed, with an overlap of at least 30cm. The asphalt concrete compaction degree should reach more than 90%. The thickness of the asphalt concrete road surface 600 should preferably be more than 30cm.

[0051] In one specific embodiment, the dimensional parameters of the anti-settlement structure 700 are as follows:

[0052] Side rib 11 is 25m long and 20cm wide. The arc rib 12 has an arc of 120°, a chord height of 20cm, and a width of 30cm. The base plate 21 has the same arc as the arc rib 12. There are 135 reinforcing ribs. The width of the reinforcing rib 13 is 10cm. The arc length of the base plate 21 is 40cm. There are 5 pillars 2 in each group. The lengths of the pillars 2 from the middle to the two sides are 50cm, 40cm, and 30cm respectively. The diameter of each pillar is 20cm. The diameter of the connecting ball 23 is 25cm. The side edge 31 is 26m long. The arc of the load-bearing plate 32 is 120°. There are 335 reinforcing ribs.

[0053] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for constructing roadbeds under adverse geological conditions, characterized in that, Includes the following steps: Step 1: Clear surface debris and excavate the soft soil foundation to the target baseline; Step 2: Lay rubble on the base, compact it, then fill with backfill material, compact it, and form the base layer; Step 3: Lay geotextile on the base layer to form the first geotextile layer, then lay graded crushed stone, compact it, then install the anti-settlement structure, and then fill it with graded crushed stone until it covers the top of the anti-settlement structure by at least 10 cm, compact it, and form the anti-settlement layer. The anti-settlement structure includes: The base frame is spherical in shape, with its opening facing upwards; Multiple support pillars, with their bottom limiters movably mounted on the base frame; The top cover includes multiple top frames that are sequentially and mutually constrained and overlapped along the transverse direction of the roadbed. The top frames are spherical in shape and have their openings facing downwards. The top frames are movably and constrained to cover the top of the support column. The top cover has a shape that is high in the middle and low on both sides along the transverse direction of the roadbed. Step 4: Lay geotextile on the anti-settlement layer to form a second geotextile layer; Step 5: Pour concrete onto the second geotextile layer to form a concrete layer; Step 6: Lay asphalt concrete on the concrete layer, compact it, and form the road surface; The base frame in step three includes a pair of side bones arranged opposite each other, a pair of arc-shaped bones connected to the two ends of the pair of side bones, and an arc-shaped reinforcing bone fixed at both ends between the pair of side bones. The arc-shaped bones are provided with multiple elongated limiting grooves along the transverse direction of the roadbed, and the bottom of the support column is movably abutted against the limiting grooves. The support column in step three includes an arc-shaped base plate that movably abuts against the limiting groove, a support rod whose bottom is fixed to the base plate, and a connecting ball fixed to the top of the support rod, wherein the connecting ball is limited to move on the top frame.

2. The method for constructing roadbeds under adverse geological conditions as described in claim 1, characterized in that, Step two involves laying the paved stones in layers and filling them with backfill material. Each layer is 50-100 mm thick. After compaction, the next layer is laid and filled.

3. The method for constructing roadbeds under adverse geological conditions as described in claim 1, characterized in that, The top frame in step three includes a pair of oppositely arranged side edges, a pair of arc-shaped load-bearing plates connected to the two ends of the pair of side edges, and arc-shaped reinforcing ribs fixed at both ends between the pair of side edges. The load-bearing plates are provided with spherical receiving grooves, and the connecting ball is movably received in the receiving grooves.

4. The method for constructing roadbeds under adverse geological conditions as described in claim 3, characterized in that, In step three, the side edges are made of channel steel, and the side edges of two adjacent top frames are interlocked.

5. The method for constructing roadbeds under adverse geological conditions as described in claim 1, characterized in that, In step three, multiple quicklime blocks are laid between the base frame and each top frame. The quicklime blocks are made by filling breathable, long, flexible bags with quicklime.

6. The method for constructing roadbeds under adverse geological conditions as described in claim 5, characterized in that, The thickness of the quicklime block in step three is 10-20 cm.

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