A cut section phosphogypsum mine pavement structure
By designing the pavement structure of the excavated phosphogypsum mine section and utilizing composite geomembrane and crushed stone blind drain technology, the problems of expansion and environmental pollution of phosphogypsum waste were solved, realizing the direct use of phosphogypsum waste as pavement structure material and environmental protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- KUNMING SURVEY DESIGN & RES INST OF CREEC
- Filing Date
- 2025-06-04
- Publication Date
- 2026-07-24
AI Technical Summary
In existing technologies, phosphogypsum waste still has the problem of expansion after harmless treatment, and cannot be directly used as a road structure material. Moreover, its stockpiling leads to environmental pollution and the emission of toxic and harmful gases, affecting people's lives and economic development.
A pavement structure for excavated sections of phosphogypsum mines is adopted, comprising a pavement layer, a water-stabilized layer, a composite geomembrane, a phosphogypsum improvement layer, medium-coarse sand, a graded crushed stone cushion layer, and a crushed stone blind drain. The phosphogypsum improvement layer is encapsulated by the composite geomembrane to isolate surface and groundwater. The material ratio of the phosphogypsum improvement layer is combined with the improvement of its expansibility. Groundwater is drained through the crushed stone blind drain to create a dry environment to ensure the stability of the pavement structure.
It has achieved efficient and comprehensive utilization of phosphogypsum waste, eliminated environmental pollution and toxic and harmful gases, improved its expansibility so that it can be directly used as a road structure material, improved road stability and skid resistance, reduced dust, and protected the environment.
Smart Images
Figure CN224548879U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of highway and municipal engineering construction technology, and in particular to a pavement structure for excavated sections of phosphogypsum mines. Background Technology
[0002] Road surface structure refers to the layered structure made of road construction materials laid on top of the subgrade soil for vehicle traffic. It serves to bear vehicle loads, resist wheel wear, and maintain a smooth road surface. Therefore, road surfaces are required to have sufficient strength, high stability, and a certain degree of smoothness. They should also have appropriate skid resistance and not generate excessive dust during driving to reduce damage to the road surface and vehicle components, maintain good visibility, and reduce environmental pollution.
[0003] Road surface materials mainly include cement concrete, asphalt concrete, or asphalt-aggregate mixtures. In areas with high phosphogypsum waste production, harmlessly treated phosphogypsum waste is also used. However, the stockpiling of phosphogypsum waste causes serious environmental pollution and excessive emissions of toxic and harmful gases, significantly impacting people's lives and economic development.
[0004] The waste phosphogypsum after harmless treatment does not cause environmental pollution or toxic and harmful gas emissions. However, its expansibility cannot be eliminated during the harmless treatment process. Therefore, it cannot be used directly as a road structure material. Its expansibility and strength need to be improved before it can be used as a road structure. Utility Model Content
[0005] The purpose of this utility model is to provide a road surface structure for excavated phosphogypsum mines, which realizes the comprehensive utilization of phosphogypsum waste after harmless treatment.
[0006] To achieve the above objectives, this utility model adopts the following technical solution: a pavement structure for excavated phosphogypsum mines, comprising a pavement layer, a water-stabilized layer, a composite geomembrane, a phosphogypsum improvement layer, medium-coarse sand, a graded crushed stone cushion layer, and a crushed stone blind drain; the phosphogypsum improvement layer is encapsulated by a composite geomembrane and placed on top of the graded crushed stone cushion layer to isolate surface and groundwater and ensure that the phosphogypsum improvement layer is in a dry environment; a water-stabilized layer is set on top, and the pavement layer is laid normally above the water-stabilized layer; the crushed stone blind drain is placed below and on both sides of the graded crushed stone cushion layer to drain groundwater and reduce the impact of groundwater on the phosphogypsum improvement layer.
[0007] Preferably, the thickness of the pavement layer is 70mm to 150mm, and the construction materials can be cement concrete, asphalt concrete, asphalt macadam mixture, etc.
[0008] Preferably, the water-stabilized layer has a thickness of 100mm, and the construction material can be stabilized crushed stone containing 3% to 5% cement. It serves as a buffer layer to protect the composite geomembrane and prevent damage to the composite geomembrane caused by the road surface construction.
[0009] Preferably, the composite geomembrane is a two-layer geotextile-one-layer geomembrane (permeable nonwoven geotextile on the top and bottom, and a waterproof geomembrane in the middle), with longitudinal and transverse tensile breaking strength ≥ 20kN / m, CBR puncture strength ≥ 4.0kN, peel strength ≥ 0.3kN / m, and width ≥ 5.0m; wherein the waterproof geomembrane is a high-density polyethylene geomembrane with a permeability coefficient not greater than 10. -11 cm / s, membrane thickness not less than 0.3mm, permeable nonwoven geotextile is polypropylene filament nonwoven geotextile.
[0010] Preferably, the thickness of the phosphogypsum modified layer is 30mm~60mm, and the construction materials are phosphogypsum, crushed stone, PO42.5 cement, S95 grade slag powder, external curing agent and water softening inhibitor; wherein the phosphogypsum content is 70%; the crushed stone content is 15%; the PO42.5 cement content is 7%; the S95 grade slag powder content is 8%; the external curing agent content is 1%; and the water softening inhibitor content is 1.2%.
[0011] Preferably, the thickness of the medium-coarse sand is 5mm to 10mm, in order to prevent the crushed stone cushion layer from puncturing the composite geomembrane.
[0012] Preferably, the thickness of the graded crushed stone cushion layer is 150mm~250mm, the purpose of which is to block the rise of underground capillary water, while taking into account some of the drainage of groundwater, and ensuring that the roadbed cushion layer is in a dry environment.
[0013] Preferably, the gravel blind drain is typically available in three sizes: 400×400mm, 500×500mm, and 600×600mm, and is composed of washed gravel or sand wrapped with a permeable non-woven geotextile.
[0014] The present invention relates to a method for on-site implementation using this structure, comprising the following steps: (1) Excavate the roadbed to the bottom of the graded crushed stone cushion layer, and at the same time complete the excavation of the soil at the location of the crushed stone blind ditch. During this period, it is necessary to do a good job of intercepting and draining around the excavation slope. (2) When constructing a crushed stone blind drain, the permeable non-woven geotextile should be laid first, and then the crushed stone or gravel should be washed and backfilled. After construction, the drainage of the blind drain should be unobstructed and water accumulation should not occur. (3) Construct a graded crushed stone subbase; (4) Lay medium-coarse sand and composite geomembrane, wherein medium-coarse sand is required to be laid on the top and bottom of the composite geomembrane; (5) Lay the phosphogypsum improvement layer. The phosphogypsum improvement should be carried out by mixing at a fixed site. After the improvement is completed, the phosphogypsum should be laid on site. At the same time, a composite geomembrane should be wrapped around the phosphogypsum improvement layer to block the dry and wet cycle of the phosphogypsum layer and ensure its own strength. (6) Lay the water-stabilized layer and at the same time do a good job of curing the water-stabilized layer; (7) Lay the road surface layer and at the same time do a good job of maintaining the road surface layer.
[0015] The advantages of this utility model are as follows: This utility model uses harmlessly treated phosphogypsum waste as a road surface structural layer, which on the one hand turns waste into treasure, eliminating environmental pollutants and toxic and harmful gases in the phosphogypsum waste; on the other hand, it improves the expansion properties of the phosphogypsum waste, making it directly usable as a road surface structural material; furthermore, by wrapping the phosphogypsum improvement layer with composite geotextile, the problems of phosphogypsum pollution and expansion properties of the improvement layer caused by construction, operation and other reasons can be further eliminated, ultimately achieving efficient and comprehensive utilization of phosphogypsum waste. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structural application of this utility model in the field; Figure 2 This is a schematic cross-sectional view of the structure of this utility model; Figure 3 This is a cross-sectional schematic diagram of the crushed stone blind drain (7) in this utility model; Figure 1-3 The annotations are as follows: 1-Road surface layer, 2-Water-stabilized layer, 3-Composite geomembrane, 4-Phosphogypsum improvement layer, 5-Medium-coarse sand, 6-Graded crushed stone cushion layer, 7-Crushed stone blind drain, 8-Washed crushed stone or gravel, 9-Permeable non-woven geotextile. Detailed Implementation
[0017] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.
[0018] like Figure 1-3The embodiment shown illustrates the following technical solution of this utility model: a pavement structure for excavated phosphogypsum mines, comprising a pavement layer 1, a water-stabilized layer 2, a composite geomembrane 3, a phosphogypsum improvement layer 4, medium-coarse sand 5, a graded crushed stone cushion layer 6, and crushed stone blind drains 7; the phosphogypsum improvement layer 4 is encased in a composite geomembrane 3 and placed on top of the graded crushed stone cushion layer 6 to isolate surface and groundwater and ensure that the phosphogypsum improvement layer 4 is in a dry environment; the water-stabilized layer 2 is set on top, and the pavement layer 1 is laid normally above the water-stabilized layer 2; the crushed stone blind drains 7 are placed on both sides to drain groundwater and reduce the impact of groundwater on the phosphogypsum improvement layer.
[0019] The thickness of the pavement layer 1 is 70mm~15mm, and the construction materials can be cement concrete, asphalt concrete, asphalt macadam mixture, etc.
[0020] The water-stabilized layer 2 has a thickness of 100mm. The construction material can be stabilized crushed stone containing 3% to 5% cement. It is a buffer layer, and its purpose is to protect the composite geomembrane 3 and prevent the composite geomembrane 3 from being damaged due to the construction of the road surface layer 1.
[0021] The composite geomembrane 3 is a two-layer geomembrane (permeable non-woven geotextile on the top and bottom, and a waterproof geomembrane in the middle), with longitudinal and transverse tensile breaking strength ≥ 20kN / m, CBR puncture strength ≥ 4.0kN, peel strength ≥ 0.3kN / m, and width ≥ 5.0m; the waterproof geomembrane is a high-density polyethylene geomembrane with a permeability coefficient not greater than 10. -11 cm / s, membrane thickness not less than 0.3mm, permeable nonwoven geotextile is polypropylene filament nonwoven geotextile.
[0022] The thickness of the phosphogypsum modified layer 4 is 30mm~60mm. The construction materials are phosphogypsum, crushed stone, PO42.5 cement, S95 grade slag powder, external curing agent and water softening inhibitor; wherein the content of phosphogypsum is 70%, the content of crushed stone is 15%, the content of PO42.5 cement is 7%, the content of S95 grade slag powder is 8%, the content of external curing agent is 1%, and the content of water softening inhibitor is 1.2%.
[0023] The thickness of the medium-coarse sand 5 is 5mm~10mm, which is to prevent the crushed stone cushion layer from puncturing the composite geomembrane.
[0024] The graded crushed stone cushion layer 6 has a thickness of 150mm~250mm. Its purpose is to block the rise of underground capillary water, while also taking into account the drainage of some groundwater, so as to ensure that the roadbed cushion layer is in a dry environment.
[0025] The gravel blind drain 7 is generally available in three sizes: 400×400mm, 500×500mm, and 600×600mm. It consists of washed gravel or sand 8 wrapped with a permeable non-woven geotextile 9.
[0026] The method for on-site implementation using this structure, as described in this embodiment of the utility model, includes the following steps: (1) Excavate the roadbed to the bottom of the graded crushed stone cushion layer 6, and at the same time complete the excavation of the soil at the location of the crushed stone blind ditch. During this period, it is necessary to do a good job of intercepting and draining around the excavation slope. (2) Constructing crushed stone blind drain 7. During the construction of the blind drain, the permeable non-woven geotextile 9 should be laid first, and then the washed crushed stone or gravel 8 should be backfilled. After construction, the blind drain should be kept dry and water accumulation should not occur. (3) Apply graded crushed stone cushion layer 6; (4) Lay medium-coarse sand 5 and composite geomembrane 3, wherein medium-coarse sand needs to be laid on the top and bottom of the composite geomembrane; (5) Lay the phosphogypsum improvement layer 4. The phosphogypsum improvement should be carried out by mixing at a fixed site. After the improvement is completed, the phosphogypsum should be laid on site. At the same time, a composite geomembrane should be wrapped around the phosphogypsum improvement layer to block the dry and wet cycle of the phosphogypsum layer and ensure its own strength. (6) Lay water-stabilized layer 2 and at the same time do a good job of curing the water-stabilized layer; (7) Lay out pavement layer 1 and at the same time maintain the pavement layer.
[0027] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A pavement structure for excavated phosphogypsum mine sections, characterized in that, The structure includes a pavement layer (1), a water-stabilized layer (2), a composite geomembrane (3), a phosphogypsum improvement layer (4) with improved expansibility of phosphogypsum waste that can be directly used as a pavement structure material, medium and coarse sand (5), a graded crushed stone cushion layer (6), and crushed stone blind drains (7). The phosphogypsum improvement layer (4) is encased in a composite geomembrane (3) and placed on top of the graded crushed stone cushion layer (6), with the water-stabilized layer (2) on top. The pavement layer (1) is laid on the water-stabilized layer (2). Crushed stone blind drains (7) are provided on both sides of the graded crushed stone cushion layer (6). The composite geomembrane (3) adopts a two-layer composite geomembrane structure with permeable nonwoven geotextile on the top and bottom and a waterproof geomembrane in the middle. The longitudinal and transverse tensile breaking strength is ≥ 20kN / m, the CBR puncture strength is ≥ 4.0kN, the peel strength is ≥ 0.3kN / m, and the width is ≥ 5.0m. The waterproof geomembrane is a high-density polyethylene geomembrane with a permeability coefficient of not more than 10. -11 cm / s, membrane thickness not less than 0.3mm, permeable nonwoven geotextile is polypropylene filament nonwoven geotextile.
2. The pavement structure for excavated phosphogypsum mine sections according to claim 1, characterized in that, The thickness of the pavement layer (1) is 70mm~150mm, and the construction materials are cement concrete, asphalt concrete or asphalt macadam mixture.
3. The pavement structure for excavated phosphogypsum mine sections according to claim 1, characterized in that, The water-stabilized layer (2) is 100mm thick and is constructed using stabilized crushed stone containing 3% to 5% cement.
4. The pavement structure for excavated phosphogypsum mine sections according to claim 1, characterized in that, The thickness of the phosphogypsum modified layer (4) is 30mm~60mm.
5. The pavement structure for excavated phosphogypsum mine sections according to claim 1, characterized in that, The thickness of the medium-coarse sand (5) is 5mm~10mm.
6. The pavement structure for excavated phosphogypsum mine sections according to claim 1, characterized in that, The thickness of the graded crushed stone cushion layer (6) is 150mm~250mm.
7. The pavement structure for excavated phosphogypsum mine sections according to claim 1, characterized in that, The gravel blind drain (7) has a size of 400×400mm, 500×500mm or 600×600mm, and is composed of washed gravel or sand (8) wrapped with a permeable non-woven geotextile (9).