A method to prevent and control road surface damage caused by "pot cover effect"

Abstract

The present invention discloses a method for preventing and controlling pavement damage induced by the "pot lid effect," which relates to the field of geotechnical engineering technology. The method includes laying a hydrophobic vapor barrier structure between the pavement and the roadbed. The structure is axially symmetrical, with a high center and low sides, and has the same slope as the pavement. The upper and lower layers are geotextiles with different offset openings and airtightness, and the middle layer is silty sand. In addition, blind ditches are provided on both sides of the sand, which are filled with water-permeable and vapor-permeable sandbags along the longitudinal direction of the roadbed. The present invention adopts the above-mentioned method for preventing and controlling pavement damage induced by the "pot lid effect," which can drain water accumulated in the lower part of the pavement and prevent deep water vapor from migrating into the micropores of the pavement concrete. This prevents the microstructure of the concrete from being damaged by frost heave, thereby ensuring the strength and stability of the pavement structure. Therefore, the present invention further considers the impact of the "pot lid effect" on the pavement microstructure, thereby effectively preventing the occurrence of pavement engineering disasters induced by water vapor circulation or freeze-thaw cycles caused by the "pot lid effect."

Description

Technical Field

[0001] The present invention relates to the field of geotechnical engineering technology, and in particular to a method for preventing and controlling road surface damage induced by a "pot cover effect." Background Art

[0002] The "pot lid effect" at airports occurs when, driven by temperature gradients, water in deep, confined soil migrates in vapor form from warmer to cooler areas, condensing into water or sublimating into ice, leading to an increase in the moisture content of the shallower soil. Northwest and Northeast my country are typically arid and cold regions, characterized by drought, low rainfall, groundwater levels reaching tens of meters, and large temperature swings between morning and evening. These factors contribute to the "pot lid effect." The accumulated water from this "pot lid effect" impacts the roadbed or pavement through perennial freeze-thaw cycles. While concrete pavement structures have low internal porosity, water vapor intrusion, coupled with long freeze-thaw cycles, damages the pavement's internal microstructure. This ultimately leads to serious problems such as pavement crumbling and uneven settlement, posing a potential threat to human life and property.

[0003] Chinese patent application number 201510455311.1 discloses a novel roadbed structure for preventing damage caused by the "pot lid effect." This structure's primary function is to prevent deep-seated water vapor from migrating to the shallower roadbed and to channel accumulated water. However, this proposal only considers the impact of the "pot lid effect" on the roadbed structure, ignoring the mechanism of damage to the pavement's microstructure and lacking specific preventive measures.

[0004] Based on the above analysis, with the increasing construction of civil aviation airports in my country, there is a huge market demand for improving airport drainage systems and preventing and controlling pavement engineering disasters, which is crucial for improving safe airport operations. Against this backdrop, the present invention overcomes the shortcomings of existing technologies and proposes a new method for preventing and controlling pavement damage induced by the "pot lid effect." This method is suitable for preventing and controlling disasters on pavement structures such as airport runways and highways, creating potential socioeconomic benefits for people's production and daily lives. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preventing and controlling pavement damage induced by the "pot cover effect", solving the problems raised in the above-mentioned background technology, and aiming to prevent and control engineering disasters such as uneven subsidence and softening of pavements of airports, highways, etc. caused by the "pot cover effect", thereby ensuring the strength and stability of the pavement, having the advantage of low maintenance cost, and providing strong guarantee for the safe operation of airports.

[0006] To achieve the above object, the present invention provides a method for preventing and controlling pavement damage induced by the "pot cover effect", comprising the following steps:

[0007] Step S1: excavate a foundation pit of a certain depth and reserve a slope equal to the road surface so that the foundation pit forms an axisymmetric structure with a high center and low sides;

[0008] Step S2: laying a lower layer of geotextile along the slope, laying a layer of silty sand on the surface of the lower layer of geotextile, and laying an upper layer of geotextile on the surface of the silty sand;

[0009] Step S3: Open blind ditches at the lowest points on both sides of the silty sand layer, fill the blind ditches with steam and water permeable sandbags, lay the steam and water permeable sandbags longitudinally, and connect them to external drainage facilities at regular intervals;

[0010] Step S4: Repeat the local unit arrangement scheme of steps S1-S3 until the actual roadbed is fully paved.

[0011] Preferably, the thickness of the lower geotextile in step S2 is set to 0.25 cm, a plurality of first permeable holes are opened on the lower geotextile, the aperture of the first permeable holes is set to 2 cm, and the center distance between two adjacent first permeable holes is set to 42 cm.

[0012] Preferably, the laying thickness of the silty sand in step S2 is set to 3 cm.

[0013] Preferably, the thickness of the upper geotextile in step S2 is set to 0.25 cm, a plurality of second permeable holes are opened on the upper geotextile, the aperture of the second permeable holes is set to 2 cm, and the center distance between two adjacent second permeable holes is set to 22 cm.

[0014] Preferably, the first water permeable holes and the second water permeable holes are arranged alternately, and the number of the second water permeable holes is greater than the number of the first water permeable holes.

[0015] Therefore, the present invention adopts the above-mentioned method for preventing and controlling the pavement damage induced by the "pot lid effect", and adopts a hydrophobic vapor barrier structure of double-layer geotextile sandwiched with silty sand, which has good overall stability and significant hydrophobic vapor barrier effect; at the same time, it reveals the principle of pavement microstructure destruction, and the construction is convenient, safe and efficient, with significant economic benefits.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a structural layout diagram of a hydrophobic vapor-isolating geotextile for preventing and controlling pavement damage induced by the "pot cover effect" of the present invention;

[0018] Figure 2 is a plan view of the upper portion of the hydrophobic vapor barrier structure;

[0019] Figure 3 is a plan view of the lower part of the hydrophobic vapor barrier structure;

[0020] Description of the accompanying drawings: 10. Road surface; 11. Upper geotextile; 12. Lower geotextile; 13. Silty sand; 14. Air-permeable and water-permeable sandbag; 15. First water-permeable hole; 16. Second water-permeable hole. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] Example

[0024] See also Figure 1-3 The present invention provides a method for preventing and controlling road surface damage caused by the "pot lid effect." The method includes laying a hydrophobic vapor barrier between the road surface and the roadbed. The structure is axially symmetrical, with a high center and low sides, and has the same slope as the road surface. The upper and lower layers are geotextiles with different staggered openings and sealing properties, and the middle layer is silty sand. In addition, blind ditches are set on both sides of the sand and filled with water- and vapor-permeable sandbags along the longitudinal direction of the roadbed. The method specifically includes the following steps:

[0025] Step S1: excavate a foundation pit of a certain depth and reserve a slope the same as that of the road surface 10 so that the foundation pit forms an axisymmetric structure with a high middle and low sides.

[0026] Step S2: Lay the lower geotextile 12 along the slope. The thickness of the lower geotextile 12 is set to 0.25 cm. A plurality of first water-permeable holes 15 are provided on the lower geotextile 12. The aperture of the first water-permeable holes 15 is set to 2 cm. The center distance between two adjacent first water-permeable holes 15 is set to 42 cm. Lay a layer of silty sand 13 on the surface of the lower geotextile 12. The laying thickness of the silty sand 13 is set to 3 cm. Lay the upper geotextile 11 on the surface of the silty sand 13. The thickness of the upper geotextile 11 is set to 0.25 cm. A plurality of second water-permeable holes 16 are provided on the upper geotextile 11. The aperture of the second water-permeable holes 16 is set to 2 cm. The center distance between two adjacent second water-permeable holes 16 is set to 22 cm. Figure 2 and Figure 3 As shown, the first and second permeable holes 15 and 16 are staggered, with the number of second permeable holes 16 exceeding the number of first permeable holes 15. The overall function of this hydrophobic vapor barrier structure is to allow some of the accumulated water beneath the pavement 10 to seep down through the first and second permeable holes 15 and 16, while the remaining water is drained down the slope into the blind ditch. Simultaneously, the lower geotextile layer 12 serves as the first line of defense against water vapor intrusion into the pavement, while the upper geotextile layer 11 serves as the second line of defense.

[0027] Step S3: Open blind ditches at the lowest points on both sides of the silty sand layer 13, fill the blind ditches with air-permeable and water-permeable sandbags 14, lay the air-permeable and water-permeable sandbags 14 longitudinally, and connect them to external drainage facilities at intervals.

[0028] Step S4: Repeat the local unit arrangement scheme of steps S1-S3 until the actual roadbed is fully paved.

[0029] The present invention solves the problem of damage to the pavement microstructure caused by water vapor migration due to the "pot lid effect". It can not only drain the water accumulation under the pavement 10, but also prevent deep water vapor from migrating into the pavement 10, forming a secondary protection for the pavement 10, ensuring the strength and structural integrity of the concrete of the pavement 10, and avoiding the damage to the internal microstructure of the pavement caused by frost heave ice crystals caused by long-term freeze-thaw cycles, thereby preventing the occurrence of disasters such as softening of the pavement concrete.

[0030] Therefore, the present invention adopts the above-mentioned method for preventing and controlling pavement damage induced by the "pot cover effect", and adopts a hydrophobic vapor barrier structure of double-layer geotextile sandwiched with silty sand, which has good overall stability and significant hydrophobic vapor barrier effect; it reveals the principle of pavement microstructure destruction, and the construction is convenient, safe and efficient, with significant economic benefits; at the same time, it further considers the impact of the "pot cover effect" on the pavement microstructure, thereby effectively preventing the occurrence of pavement engineering disasters induced by water vapor circulation or freeze-thaw cycles caused by the "pot cover effect".

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preventing and controlling road surface damage induced by the "pot cover effect", characterized in that: The following steps are involved: Step S1: excavate a foundation pit of a certain depth and reserve a slope equal to the road surface so that the foundation pit forms an axisymmetric structure with a high center and low sides; Step S2: laying a lower layer of geotextile along the slope, laying a layer of silty sand on the surface of the lower layer of geotextile, and laying an upper layer of geotextile on the surface of the silty sand; The thickness of the lower geotextile in step S2 is set to 0.25 cm, and the lower geotextile is provided with a plurality of first permeable holes, the aperture of the first permeable holes is set to 2 cm, and the center distance between two adjacent first permeable holes is set to 42 cm; The thickness of the upper geotextile in step S2 is set to 0.25 cm, and a plurality of second permeable holes are opened on the upper geotextile. The aperture of the second permeable holes is set to 2 cm, and the center distance between two adjacent second permeable holes is set to 22 cm. The first water-permeable holes and the second water-permeable holes are arranged alternately, and the number of the second water-permeable holes is greater than the number of the first water-permeable holes; Step S3: Open blind ditches at the lowest points on both sides of the silty sand layer, fill the blind ditches with steam and water permeable sandbags, lay the steam and water permeable sandbags longitudinally, and connect them to external drainage facilities at regular intervals; Step S4: Repeat the local unit arrangement scheme of steps S1-S3 until the actual roadbed is fully paved.

2. The method for preventing and controlling pavement damage induced by the "pot lid effect" according to claim 1, characterized in that: The laying thickness of the silty sand in step S2 is set to 3 cm.

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