Seasonal frozen soil region subgrade structure and construction method thereof

Abstract

The invention discloses a seasonal frozen soil region subgrade structure and a construction method thereof. The subgrade structure sequentially comprises a light foam layer, a low-liquid-limit clay layer, a composite geomembrane layer, a subgrade filling layer, a gravel layer, a metalling layer, a medium coarse sand layer and a composite heat preservation cushion layer from bottom to top, whereina fiber concrete layer is arranged on the upper surface of the composite heat preservation cushion layer, the section of the fiber concrete layer is in a double-layer trapezoid shape, and the fiber concrete is coated with a subgrade filler. According to the structure and the method, the service life of the subgrade is prolonged, the overall long-term stability of the subgrade structure of the seasonal frozen soil area is ensured, and the defects of insufficient toughness, poor freeze thawing resistance, easy cracking and weak seepage resistance of plain concrete are overcome.

Description

technical field

[0001] The invention relates to the technical field of roadbed structures and building materials, in particular to a roadbed structure in seasonally frozen soil regions and a construction method thereof. Background technique

[0002] At present, the area of ​​seasonally frozen soil in my country is 5.14×10 6 km 2 , where the area with a freezing depth greater than 0.5m is as high as 4.46×10 6 km 2 , accounting for 46.3% of the country's total land area, this freezing depth will have a serious impact on geotechnical engineering construction. Due to climate warming, most of the permafrost regions gradually melted and turned into seasonally frozen regions, which increased the area of ​​seasonally frozen regions by 2.15×10 6 km 2 . More than 60% of my country's railways are located in seasonally frozen soil regions, and projects with a frozen soil layer depth of more than 0.5m are mostly located in the northeast, north, and northwest regions. According to ...

Examples

Embodiment 1

[0027] A subgrade structure in a seasonally frozen soil area, the subgrade structure from bottom to top is a light foam layer, a low liquid limit clay layer, a composite geomembrane layer, a roadbed filler layer, a crushed stone layer, a gravel layer, and a medium-coarse sand layer layer and a composite thermal insulation cushion, the composite thermal insulation cushion is above the fiber concrete layer, the cross section of the fiber concrete layer is double trapezoidal, and the fiber concrete is covered with roadbed filler. Its construction method steps are as follows:

[0028] Step 1: Excavate the frozen soil, level the surface, and lay lightweight foam, with the air bubbles accounting for 45% to 65% of the volume;

[0029] Step 2: lay low liquid limit clay, which can play the role of capillary water isolation, rolling 3 to 4 times;

[0030] Step 3: Lay the composite geomembrane, pave the entire width flat, and the outer edge is exposed by 2 to 3 cm. The composite geomemb...

Embodiment 2

[0046] A subgrade structure in a seasonally frozen soil area, the subgrade structure from bottom to top is a light foam layer, a low liquid limit clay layer, a composite geomembrane layer, a roadbed filler layer, a crushed stone layer, a gravel layer, and a medium-coarse sand layer layer and a composite thermal insulation cushion, the composite thermal insulation cushion is above the fiber concrete layer, the cross section of the fiber concrete layer is double trapezoidal, and the fiber concrete is covered with roadbed filler. Both sides of the fiber concrete layer are designed as slope-shaped steps with a slope of 1:1.5 to 1:1.75, and the edge of the upper trapezoidal slope foot is not less than 40cm from the edge of the lower trapezoidal slope top. The above-mentioned fiber concrete, including the following raw materials in parts by weight: 25 parts of cement, 10 parts of sand, 21 parts of gravel, 18 parts of fly ash, 13 parts of slag, 14 parts of anhydrite, 3 parts of silica...

Embodiment 3

[0053] A subgrade structure in a seasonally frozen soil area, the subgrade structure from bottom to top is a light foam layer, a low liquid limit clay layer, a composite geomembrane layer, a roadbed filler layer, a crushed stone layer, a gravel layer, and a medium-coarse sand layer layer and a composite thermal insulation cushion, the composite thermal insulation cushion is above the fiber concrete layer, the cross section of the fiber concrete layer is double trapezoidal, and the fiber concrete is covered with roadbed filler. Both sides of the fiber concrete layer are designed as slope-shaped steps with a slope of 1:1.5 to 1:1.75, and the edge of the upper trapezoidal slope foot is not less than 40cm from the edge of the lower trapezoidal slope top. The above-mentioned fiber concrete includes the following raw materials in parts by weight: 28 parts of cement, 12 parts of sand, 16 parts of crushed stone, 15 parts of fly ash, 12 parts of slag, 12 parts of anhydrite, 4 parts of s...

technical field

[0001] The invention relates to the technical field of roadbed structures and building materials, in particular to a roadbed structure in seasonally frozen soil regions and a construction method thereof. Background technique

[0002] At present, the area of ​​seasonally frozen soil in my country is 5.14×10 6 km 2 , where the area with a freezing depth greater than 0.5m is as high as 4.46×10 6 km 2 , accounting for 46.3% of the country's total land area, this freezing depth will have a serious impact on geotechnical engineering construction. Due to climate warming, most of the permafrost regions gradually melted and turned into seasonally frozen regions, which increased the area of ​​seasonally frozen regions by 2.15×10 6 km 2 . More than 60% of my country's railways are located in seasonally frozen soil regions, and projects with a frozen soil layer depth of more than 0.5m are mostly located in the northeast, north, and northwest regions. According to ...

Examples

Embodiment 1

[0027] A subgrade structure in a seasonally frozen soil area, the subgrade structure from bottom to top is a light foam layer, a low liquid limit clay layer, a composite geomembrane layer, a roadbed filler layer, a crushed stone layer, a gravel layer, and a medium-coarse sand layer layer and a composite thermal insulation cushion, the composite thermal insulation cushion is above the fiber concrete layer, the cross section of the fiber concrete layer is double trapezoidal, and the fiber concrete is covered with roadbed filler. Its construction method steps are as follows:

[0028] Step 1: Excavate the frozen soil, level the surface, and lay lightweight foam, with the air bubbles accounting for 45% to 65% of the volume;

[0029] Step 2: lay low liquid limit clay, which can play the role of capillary water isolation, rolling 3 to 4 times;

[0030] Step 3: Lay the composite geomembrane, pave the entire width flat, and the outer edge is exposed by 2 to 3 cm. The composite geomemb...

Embodiment 2

[0046] A subgrade structure in a seasonally frozen soil area, the subgrade structure from bottom to top is a light foam layer, a low liquid limit clay layer, a composite geomembrane layer, a roadbed filler layer, a crushed stone layer, a gravel layer, and a medium-coarse sand layer layer and a composite thermal insulation cushion, the composite thermal insulation cushion is above the fiber concrete layer, the cross section of the fiber concrete layer is double trapezoidal, and the fiber concrete is covered with roadbed filler. Both sides of the fiber concrete layer are designed as slope-shaped steps with a slope of 1:1.5 to 1:1.75, and the edge of the upper trapezoidal slope foot is not less than 40cm from the edge of the lower trapezoidal slope top. The above-mentioned fiber concrete, including the following raw materials in parts by weight: 25 parts of cement, 10 parts of sand, 21 parts of gravel, 18 parts of fly ash, 13 parts of slag, 14 parts of anhydrite, 3 parts of silica...

Embodiment 3

[0053] A subgrade structure in a seasonally frozen soil area, the subgrade structure from bottom to top is a light foam layer, a low liquid limit clay layer, a composite geomembrane layer, a roadbed filler layer, a crushed stone layer, a gravel layer, and a medium-coarse sand layer layer and a composite thermal insulation cushion, the composite thermal insulation cushion is above the fiber concrete layer, the cross section of the fiber concrete layer is double trapezoidal, and the fiber concrete is covered with roadbed filler. Both sides of the fiber concrete layer are designed as slope-shaped steps with a slope of 1:1.5 to 1:1.75, and the edge of the upper trapezoidal slope foot is not less than 40cm from the edge of the lower trapezoidal slope top. The above-mentioned fiber concrete includes the following raw materials in parts by weight: 28 parts of cement, 12 parts of sand, 16 parts of crushed stone, 15 parts of fly ash, 12 parts of slag, 12 parts of anhydrite, 4 parts of s...

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