CN110777592A

CN110777592A - Low embankment ventilation pipe roadbed structure in plateau permafrost region

Info

Publication number: CN110777592A
Application number: CN201911075741.5A
Authority: CN
Inventors: 王多青; 王平; 刘佑农
Original assignee: China Railway First Survey and Design Institute Group Ltd
Current assignee: China Railway First Survey and Design Institute Group Ltd
Priority date: 2019-11-06
Filing date: 2019-11-06
Publication date: 2020-02-11

Abstract

The invention relates to a low embankment ventilating pipe roadbed structure in a permafrost region of a plateau, which comprises a foundation pit replacement part below the ground and an embankment replacement part above the ground, wherein two sides of the embankment replacement part are provided with a rubble berm; and transverse ventilation pipes are arranged above the natural upper limit of the frozen soil in the foundation pit replacement part, are longitudinally arranged in parallel at intervals, and extend upwards into the rubble protecting channel along the foundation pit side slope at two ends of each ventilation pipe and lead to the outside. The invention organically combines passive heat preservation (filling and heat preservation plates) and active cooling (ventilating pipes and flaky stone protection channels), and comprehensively protects permafrost soil with multiple pipes; the ventilation pipe is constructed according to a half-width method and a spacing method, so that the operation field is wide, the construction and transportation are smooth, and the shape of the groove is regular; the invention enriches permafrost low embankment frozen soil protection technology, and provides a new idea and a new method for solving the technical problems of frozen soil thawing and sinking and foundation settlement in plateau permafrost regions.

Description

Low embankment ventilation pipe roadbed structure in plateau permafrost region

Technical Field

The invention relates to a roadbed structure, in particular to a ventilating pipe roadbed structure of a low embankment in a permafrost region of a plateau.

Background

In the construction of Qinghai-Tibet railway, a great deal of rubble gas cooling, ventilation pipes and heat pipes are applied to protect permafrost, the rubble gas cooling is applied to the embankment with the soil filling height of more than 2.5m, the ventilation pipes are applied to the embankment with the soil filling height of more than 4.0m, and the heat pipes are used for the embankment with the soil filling height of less than 2.5m (called as 'low embankment' for short) and the cutting because of being expensive.

At present, the technology for actively protecting frozen soil applied to a high embankment (the filling height is more than 2.5 m) is abundant, such as air cooling of rubble, rubble slope protection, ventilation pipes and heat pipes, and even a bridge is used for replacing roads, while the technology for actively protecting frozen soil applied to a low embankment is relatively limited and is commonly used with heat pipes. Based on this, in order to improve market competitiveness and strengthen technical reserve, it is necessary to research and develop a new structure of frozen soil roadbed suitable for low embankment section.

Disclosure of Invention

The invention aims to provide a ventilating pipe roadbed structure of a low embankment in a permafrost region of a plateau, which overcomes the defects in the prior art.

The technical scheme adopted by the invention is as follows:

plateau permafrost region low embankment ventilation pipe roadbed structure, its characterized in that:

the roadbed structure comprises a foundation pit replacement part below the ground and an embankment replacement part above the ground, wherein two sides of the embankment replacement part are provided with a stone protecting channel;

and transverse ventilation pipes are arranged above the natural upper limit of the frozen soil in the foundation pit replacement part, are longitudinally arranged in parallel at intervals, and extend upwards into the rubble protecting channel along the foundation pit side slope at two ends of each ventilation pipe and lead to the outside.

And a heat insulation plate is arranged in the embankment replacement part above the ventilation pipe.

The ventilation pipe is an assembled corrugated pipe, and pipe sections are connected in a sleeve or flange mode.

The pipe orifice parts at the two ends of the ventilation pipe are bent and change the direction when rotating.

And excavating and replacing coarse-grained soil in the foundation pit replacing and filling part.

The middle coarse sand cushion layer is paved on the upper part and the lower part of the heat preservation plate.

The invention has the following advantages:

the structure comprises a substrate replacement layer, a ventilation pipe, a heat insulation plate and a flake stone protection channel, wherein passive heat insulation (filling soil and the heat insulation plate) and active cooling (the ventilation pipe and the flake stone protection channel) are organically combined, and permafrost soil is comprehensively protected by multiple pipes. The ventilation pipe is constructed according to a half-width method and a spacing method, so that the operation field is wide, the construction and transportation are smooth, and the shape of the groove is regular. The invention enriches permafrost low embankment frozen soil protection technology, and provides a new idea and a new method for solving the technical problems of frozen soil thawing and sinking and foundation settlement in plateau permafrost regions.

Drawings

FIG. 1 is a cross-sectional view of the present invention.

In the figure, 1-a stone protective road, 2-a vent pipe orifice, 3-an insulation board, 4-a vent pipe, 5-a foundation pit sideline, 6-excavation, replacement and filling of coarse-grained soil, 7-high ice content frozen soil and 8-a natural upper limit of the frozen soil.

Detailed Description

The present invention will be described in detail with reference to specific embodiments.

The invention relates to a low embankment ventilating subgrade structure in a permafrost region of a plateau, which comprises a foundation pit filling part below the ground and an embankment filling part above the ground, wherein two sides of the embankment filling part are provided with a flaky stone protective road 1, the height of the flaky stone protective road is flush with a roadbed surface, the width of the flaky stone protective road is 2.0m, and the flaky stone is hard, frost-resistant and difficult-to-weather rock and has the particle size of 0.1-0.3 m. And transverse ventilation pipes 4 are arranged above the natural upper limit 8 of the frozen soil in the foundation pit replacement part and are longitudinally arranged in parallel at intervals, and two ends of each ventilation pipe 4 upwards extend into the rubble protecting channel 1 along the foundation pit side slope and lead to the outside.

And a heat insulation plate 3 is arranged in the embankment replacement part above the ventilation pipe 4 and is positioned 0.80m below the roadbed surface. The heat insulation board is made of EPS (expanded polystyrene) and other boards with high strength and good toughness, and the thickness of the heat insulation board is 60-80 mm.

The ventilation pipe 4 is an assembled corrugated pipe, and pipe sections are connected in a sleeve or flange mode. The ventilating pipe mouths 2 at the two ends of the ventilating pipe 4 are partially bent and change the direction when rotating. The ventilation pipe is made of metal corrugated pipes, and pipe sections are connected in a sleeve or flange mode and can be customized according to requirements. The effective aperture of the ventilation pipe is 0.3-0.4 m, and the distance is 1.6-2.0 m. The pipe orifice of the ventilation pipe extends out of the side slope of the protective road by not less than 0.3 m and is 0.7 m higher than the ground surface, and the pipe orifice of the main wind side is higher than the pipe orifice of the secondary wind side. The orientation of the pipe orifice can be adjusted according to wind direction and climate conditions.

And excavating and replacing coarse granular soil in the replacement and filling part of the foundation pit, wherein the replacement and filling thickness is 1.4 times of the natural upper limit value, but not more than 3.0 m. The upper and lower parts of the heat insulation plate 3 are respectively paved with medium and coarse sand cushions with the thickness of 0.20 m.

The construction process of the invention is as follows:

1. the construction is preferably arranged to be completed before the spring melt.

2. Sufficient mechanical equipment and material materials are prepared before construction, and cover cloth, temporary supports and the like used in rainy and snowy days are prepared, so that the exposed area can be covered in time.

3. And excavating the foundation to replace the soil filled with coarse particles to the top surface of the ventilation pipe, and manually or mechanically excavating a groove according to the position of the ventilation pipe to bury the ventilation pipe. The ventilation pipe is buried along the foundation pit wall as much as possible.

(1) And after filling and compacting below the ventilation pipe and meeting the requirements, performing ventilation pipe construction according to a half-width method and an interval method. The half-width method: dividing the operation surface into a left half and a right half by a line central line; the spacing method comprises the following steps: and excavating grooves at intervals and installing ventilation pipes. Thus, smooth transportation in the construction process can be ensured; the grooved earthwork can also be piled on the other half of the roadbed; the interval excavation is favorable for guaranteeing the shape of the groove and increasing the working surface.

(2) The bottom of the groove is leveled by medium coarse sand, and the periphery of the pipe body is tightly filled.

(3) The ventilation pipe is made of metal corrugated pipes, is connected in a flange mode, and can be customized according to needs.

4. And after the ventilation pipe is installed, continuously filling soil and constructing an insulation board.

(1) In order to prevent the heat-insulating plate from being damaged or deformed, a middle and coarse sand protective layer with the thickness of 0.20m is respectively paved on the upper part and the lower part of the heat-insulating plate when the heat-insulating plate is paved.

(2) After a layer of soil material is filled on the upper portion of the heat insulation plate, mechanical rolling is carried out again to prevent the heat insulation plate from being large in compression deformation and reduce the heat insulation effect.

(3) The joint treatment of the heat-insulating plate adopts an adhesive bonding method, a groove lapping method or a joint foaming connecting method.

5. And (4) filling stone protecting channels on two sides of the roadbed, and paying attention to protect the ventilation pipe from being damaged. The flaky stone is hard, frost-resistant and difficult-to-weather rock with the grain size of 0.1-0.3 m.

The invention is not limited to the examples, and any equivalent changes to the technical solution of the invention by a person skilled in the art after reading the description of the invention are covered by the claims of the invention.

Claims

1. Plateau permafrost region low embankment ventilation pipe roadbed structure, its characterized in that:

the roadbed structure comprises a foundation pit replacement part below the ground and an embankment replacement part above the ground, wherein two sides of the embankment replacement part are provided with a stone protecting channel (1);

and transverse ventilation pipes (4) are arranged above the natural upper limit (8) of the frozen soil in the foundation pit replacement part and are longitudinally arranged in parallel at intervals, and two ends of each ventilation pipe (4) upwards extend into the rubble protecting channel (1) along the foundation pit side slope and lead to the outside.

2. The plateau permafrost region low embankment ventilation pipe roadbed structure of claim 1, which is characterized in that:

an insulation board (3) is arranged in the embankment replacement part above the ventilation pipe (4).

3. The plateau permafrost region low embankment ventilation pipe roadbed structure of claim 2, which is characterized in that:

the ventilation pipe (4) is an assembled corrugated pipe, and pipe sections are connected in a sleeve or flange mode.

4. The plateau permafrost region low embankment ventilation pipe roadbed structure of claim 3, wherein:

the pipe orifices (2) at the two ends of the vent pipe (4) are partially bent and change the direction when rotating.

5. The plateau permafrost region low embankment ventilation pipe roadbed structure of claim 4, wherein:

6. The plateau permafrost region low embankment ventilation pipe roadbed structure of claim 5, wherein:

the middle coarse sand cushion layer is paved on the upper and lower surfaces of the heat insulation plate (3).