CN101307586A - Broken stone slope protector and air-duct composite roadbed - Google Patents

Abstract

The invention relates to a complex roadbed with crushed stone revetment and vent-pipe. The structure of the complex roadbed is characterized in that embankment fill closely compacted is placed on the compacted natural group surface, and horizontal vent-pipes vertical to the roadbed direction are laid inside the embankment fill, and crushed stone revetments are filled in both sides of the roadbed, and horizontal vent-pipes penetrate the crushed stone revetments. The invention fully utilizes the natural convection temperature reduction effect of the crushed stone revetments and the fast ventilation temperature reduction characteristic of the vent-pipes, and combines advantages of both sides to realize the temperature reduction of lower frozen earth, increase the upper limit of the frozen earth and realize the even distribution of temperature of the frozen earth below the roadbed, thereby preventing damages of roadbeds caused due to the frost heaving and the thaw settlement generated in the process of the freeze thawing of seasonal active layers and ensuring the long-term stability of roadbeds of high grade highways in permafrost regions.

Description

Broken stone slope protector and air-duct composite roadbed

Technical field

The present invention relates to a kind of structure of road, especially a kind of broken stone slope protector and air-duct composite roadbed.It can reduce High-Grade Highway Subgrade bottom frozen soils temperature effectively, and the lifting frozen soil upper limit improves frozen earth roadbed stability.

Background technology

China's ever-frozen ground mainly is distributed in large and small Xing'an Mountains and song-Nen plain is northern and western high mountain and Qinghai-Tibet Platean, accounts for 22.4% of area.In the many highway constructions of China, for example Qinghai-Tibet Railway, Qinghai-Tibet Highway (109 national highway), 214 national highways and the Qinghai-Tibet speedway etc. of having included Ministry of Communications planning in all are faced with the frozen soil problem.With regard to Qinghai-Tibet Railway, total 632km passes through the ever-frozen ground district, wherein have 275km to be in high temperature ever-frozen ground district (annual mean ground temperature 〉=-1.0 ℃), have 221km to pass through high ice content ever-frozen ground district (volume ice content 〉=20%), high temperature, the overlapping highway section of hight-ice-content permafrost are 134km.Therefore, for cold district highway construction, all can face severe frozen soil problem.With regard to the Qinghai-Tibet speedway of having included at present Ministry of Communications's planning in, resolving the frozen soil problem will become the core and key of guaranteeing its safety and stability.

In order to resolve the frozen soil problem, guarantee the safety and stability of ever-frozen ground district road, (Niu Fujun such as Niu Fujun, Cheng Guodong, Lai Yuanming. Qinghai-Tibet Railway ventilation embankment Eccentric Loads in Layered Soils and Research. Xi'an engineering college journal, 2002,24 (3): 1-6) find that by laboratory test duct-ventilated embankment can effectively reduce bottom soil body temperature, but, can cause the differential settlement of roadbed because asymmetry appears in roadbed temperature of lower field.(Sun Zhizhong such as Sun Zhizhong, Ma Wei, Li Dongqing. the experimental study of permafrost region pitched work roadbed thermoregulation effect. rock mechanics, 2006,27 (11): 2001-2004) thermoregulation effect to Qinghai-Tibet Railway pitched work roadbed has carried out finding in the research: the broken stone slope protector roadbed plays the effect of cooling preferably to roadbed toe place frozen soil, but roadbed middle part soil body temperature still is in relative higher state, and the unbalanced of this thermal field will hiding some dangers for for subgrade defect.And higher for pavement temperature, the cold district high-grade highway that width of subgrade is bigger will have more problem and occur.Therefore, under the condition of global warming,, especially build high-grade highway and only adopt a kind of engineering measure to guarantee that subgrade stability is quite difficult in high temperature ever-frozen ground district in the ever-frozen ground district.

Summary of the invention

Under the overall background of global warming, for realizing protection, guarantee the safety and stability of road to ever-frozen ground under ever-frozen ground district (the especially high temperature ever-frozen ground district) High-Grade Highway Subgrade, the invention provides a kind of broken stone slope protector and air-duct composite roadbed.It is according to the Qinghai-Tibet Platean climate characteristic that the four seasons temperature difference is big, temperature is lower than surface temperature usually, utilize the quick aeration-cooling characteristics of the cooling effect of natural convection and the air chimney of broken stone slope protector, both combine and realize reduction to High-Grade Highway Subgrade bottom frozen soils temperature, the lifting ever-frozen ground upper limit is guaranteed frozen earth roadbed stablizing for many years.

Purpose of the present invention can be achieved through the following technical solutions:

A kind of broken stone slope protector and air-duct composite roadbed, it is the embankment filled soil that on the natural surface of compacting, is equipped with the densification compacting, be equipped with the horizontal air chimney of perforation in the embankment filled soil, and perpendicular to road-trend, again broken stone slope protector is dosed in the roadbed both sides, and horizontal air chimney runs through broken stone slope protector.

The air chimney diameter is 0.2～1.0m, and the tube and tube axis spacing is 2～3 times of calibers, and the air chimney axis is 0.5～4.0m apart from natural surface.Bank protection piece ballast grain sizes is 10～30cm, and horizontal breadth is 0.5～2.5m.

Above-mentioned broken stone slope protector and air-duct composite roadbed operating principle are to utilize the quick aeration-cooling characteristics of the cooling effect of natural convection and the air chimney of broken stone slope protector, both advantages are combined realize cooling effect to bottom frozen soil.Its course of work can be described as: when winter, outside air temperature was low, the broken stone slope protector outside and upper temp are lower than the inboard, the outer top of inner air density is greater than interior bottom, under the effect of gravity and buoyancy lift, cool ambient air flows into from the broken stone slope protector bottom side, internal heat air come-up, and flowing of air brought outside " cold " in the roadbed into, simultaneously " heat " in the roadbed taken out of, realized cooling effect the roadbed side slope and the bottom soil body; When summer, ambient temperature was higher, the outer upper temp of broken stone slope protector was higher than interior bottom, and the outer top of atmospheric density is less than interior bottom, and air is in relative static conditions, and no convection current takes place.Air chimney crosses roadbed; realize change by quick ventilation to the surrounding soil temperature; because ever-frozen ground district average temperature of the whole year is lower than 0 ℃; and has the climatic characteristic that dry monsoon is big, wet monsoon is little; thereby air chimney has been realized the accumulation to the roadbed subzero temperature, reaches the purpose of protection bottom frozen soil.The present invention has made full use of the work characteristics of broken stone slope protector and air chimney, can effectively reduce its underpart frozen soils temperature, improves frozen soil upper limit, prevents the generation of frozen earth roadbed frost heave and thaw collapse.

In order to verify broken stone slope protector and air-duct composite roadbed cooling-down effect, each region energy transmission of the present invention is found the solution by following governing equation:

1) ventilation area under control:

Flowing of roadbed ventilation inner air tube is turbulent flow, and its governing equation is as follows:

Continuity equation:

$\frac{{\∂v}_x}{\∂x}+\frac{{\∂v}_y}{\∂y}+\frac{{\∂v}_z}{\∂z}=0---\left(1\right)$

The equation of momentum:

$\mathrm{\ρ}\frac{\∂v_x}{\∂t}+\mathrm{\ρ}(\frac{\∂\left(v_x{v}_x\right)}{\∂x}+\frac{\∂\left(v_y{v}_x\right)}{\∂y}+\frac{\∂\left(v_z{v}_x\right)}{\∂z})=-\frac{\∂p}{\∂x}+\frac{\∂}{\∂x}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_x}{\∂x}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_x}{\∂y}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_x}{\∂z}\right]$

$+\frac{\∂}{\∂x}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{{\∂v}_x}{\∂x}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_y}{\∂x}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_z}{\∂x}\right]---\left(2a\right)$

$\mathrm{\ρ}\frac{\∂v_y}{\∂t}+\mathrm{\ρ}(\frac{\∂\left(v_x{v}_y\right)}{\∂x}+\frac{\∂\left(v_y{v}_y\right)}{\∂y}+\frac{\∂\left(v_z{v}_y\right)}{\∂z})=-\frac{\∂p}{\∂y}+\frac{\∂}{\∂x}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_y}{\∂x}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_y}{\∂y}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_y}{\∂z}\right]$

$+\frac{\∂}{\∂x}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{{\∂v}_x}{\∂y}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_y}{\∂y}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_z}{\∂y}\right]---\left(2b\right)$

$\mathrm{\ρ}\frac{\∂v_z}{\∂t}+\mathrm{\ρ}(\frac{\∂\left(v_x{v}_z\right)}{\∂x}+\frac{\∂\left(v_y{v}_z\right)}{\∂y}+\frac{\∂\left(v_z{v}_z\right)}{\∂z})=-\frac{\∂p}{\∂z}+\frac{\∂}{\∂x}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_z}{\∂x}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_z}{\∂y}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_z}{\∂z}\right]$

$+\frac{\∂}{\∂x}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{{\∂v}_x}{\∂z}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_y}{\∂z}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+{\mathrm{\η}}_t)\frac{\∂v_z}{\∂z}\right]---\left(2c\right)$

Pulse energy k equation:

$\mathrm{\ρ}\frac{\∂k}{\∂t}+\mathrm{\ρ}(\frac{\∂\left(v_{x}k\right)}{\∂x}+\frac{\∂\left(v_{y}k\right)}{\∂y}+\frac{\∂\left(v_{z}k\right)}{\∂z})=\frac{\∂}{\∂x}\left[(\mathrm{\η}+\frac{{\mathrm{\η}}_t}{{\mathrm{\σ}}_k})\frac{\∂k}{\∂x}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+\frac{{\mathrm{\η}}_t}{{\mathrm{\σ}}_k})\frac{\∂k}{\∂y}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+\frac{{\mathrm{\η}}_t}{{\mathrm{\σ}}_k})\frac{\∂k}{\∂z}\right]$

$+{\mathrm{\η}}_t\left\{2\right[{\left(\frac{\∂v_x}{\∂x}\right)}^2+{\left(\frac{\∂v_y}{\∂y}\right)}^2+{\left(\frac{\∂v_z}{\∂z}\right)}^2]+{(\frac{\∂v_x}{\∂y}+\frac{\∂v_y}{\∂x})}^2+{(\frac{\∂v_x}{\∂z}+\frac{\∂v_z}{\∂x})}^2+{(\frac{\∂v_y}{\∂z}+\frac{\∂v_z}{\∂y})}^2\}-\mathrm{\ρ\ϵ}---\left(3\right)$

Dissipative shock wave ε equation:

$\mathrm{\ρ}\frac{\∂\mathrm{\ϵ}}{\∂t}+\mathrm{\ρ}(\frac{\∂\left(v_x\mathrm{\ϵ}\right)}{\∂x}+\frac{\∂\left(v_y\mathrm{\ϵ}\right)}{\∂y}+\frac{\∂\left(v_z\mathrm{\ϵ}\right)}{\∂z})=\frac{\∂}{\∂x}\left[(\mathrm{\η}+\frac{{\mathrm{\η}}_t}{{\mathrm{\σ}}_{\mathrm{\ϵ}}})\frac{\∂\mathrm{\ϵ}}{\∂x}\right]+\frac{\∂}{\∂y}\left[(\mathrm{\η}+\frac{{\mathrm{\η}}_t}{{\mathrm{\σ}}_{\mathrm{\ϵ}}})\frac{\∂\mathrm{\ϵ}}{\∂y}\right]+\frac{\∂}{\∂z}\left[(\mathrm{\η}+\frac{{\mathrm{\η}}_t}{{\mathrm{\σ}}_{\mathrm{\ϵ}}})\frac{\∂\mathrm{\ϵ}}{\∂z}\right]$

$+\frac{{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="A20081001837200102.png,A20081001837200111.png"\; state="\{\{state\}\}">c</figure-callout>}}_1\mathrm{\&epsiv;}}{k}{\mathrm{\&eta;}}_t\left\{2\right[{\left(\frac{\&PartialD;v_x}{\&PartialD;x}\right)}^2+{\left(\frac{\&PartialD;v_y}{\&PartialD;y}\right)}^2+{\left(\frac{\&PartialD;v_z}{\&PartialD;z}\right)}^2]+{(\frac{\&PartialD;v_x}{\&PartialD;y}+\frac{\&PartialD;v_y}{\&PartialD;x})}^2+{(\frac{\&PartialD;v_x}{\&PartialD;z}+\frac{\&PartialD;v_z}{\&PartialD;x})}^2+{(\frac{\&PartialD;v_y}{\&PartialD;z}+\frac{\&PartialD;v_z}{\&PartialD;y})}^2\}$

$-{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="A20081001837200101.png,A20081001837200102.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\mathrm{\&rho;}\frac{{\mathrm{\&epsiv;}}^2}{k}---\left(4\right)$

The coefficient of eddy viscosity equation:

η _t＝c _μρk ²/ε(5)

Energy equation:

$\mathrm{\&rho;}\frac{\&PartialD;T}{\&PartialD;t}+\mathrm{\&rho;}(\frac{\&PartialD;\left(v_{x}T\right)}{\&PartialD;x}+\frac{\&PartialD;\left(v_{y}T\right)}{\&PartialD;y}+\frac{\&PartialD;\left(v_{z}T\right)}{\&PartialD;z})=\frac{\&PartialD;}{\&PartialD;x}\left[(\frac{\mathrm{\&lambda;}}{c_p}+\frac{{\mathrm{\&eta;}}_t}{{\mathrm{\&sigma;}}_T})\frac{\&PartialD;T}{\&PartialD;x}\right]$

$+\frac{\&PartialD;}{\&PartialD;y}\left[(\frac{\mathrm{\&lambda;}}{c_p}+\frac{{\mathrm{\&eta;}}_t}{{\mathrm{\&sigma;}}_T})\frac{\&PartialD;T}{\&PartialD;y}\right]+\frac{\&PartialD;}{\&PartialD;z}\left[(\frac{\mathrm{\&lambda;}}{c_p}+\frac{{\mathrm{\&eta;}}_t}{{\mathrm{\&sigma;}}_T})\frac{\&PartialD;T}{\&PartialD;z}\right]---\left(6\right)$

In the formula: v _x, v _y, v _zBe respectively x, y, the axial speed air flow of z; P is an atmospheric pressure; η is the dynamic viscosity of air, and is only relevant with the rerum natura of air; η _tCoefficient of eddy viscosity for air depends on flow regime, is the space coordinates function; ρ is an atmospheric density; K is a pulse energy; ε is the dissipative shock wave of pulse energy; T is a temperature; T is the time; σ _k, σ _ε, σ _T, c ₁, c ₂, c _uBe constant; λ, c _pBe respectively the coefficient of thermal conductivity and the specific heat capacity at constant pressure of air.

2) piece rubble district

Pipe-massive stone layer can be counted as porous media, and its inner air natural convection governing equation group is:

Continuity equation:

$\frac{\&PartialD;v_x}{\&PartialD;x}+\frac{\&PartialD;v_y}{\&PartialD;y}+\frac{\&PartialD;v_z}{\&PartialD;z}=0---\left(7\right)$

In the formula: v _x, v _yBe respectively air seepage velocity component in the x and y direction.

The equation of momentum:

$\frac{\&PartialD;p}{\&PartialD;x}=-\frac{\mathrm{\&eta;}}{k}{v}_x-\mathrm{\&rho;B}\left|v\right|v_x---\left(8a\right)$

$\frac{\&PartialD;p}{\&PartialD;y}=-\frac{\mathrm{\&eta;}}{k}{v}_y-\mathrm{\&rho;B}\left|v\right|v_y---\left(8b\right)$

$\frac{\&PartialD;p}{\&PartialD;z}=-\frac{\mathrm{\&eta;}}{k}{v}_z-\mathrm{\&rho;B}\left|v\right|v_z-{\mathrm{\&rho;}}_0[1-\mathrm{\&beta;}(T-T_0)]g---\left(8c\right)$

In the formula: $\left|v\right|=\sqrt{v_x^2+{\mathrm{<figure-callout\; id="2"\; label="v\; y"\; filenames="A20081001837200101.png,A20081001837200102.png"\; state="\{\{state\}\}">v</figure-callout>}}_y^{}+{\mathrm{<figure-callout\; id="2"\; label="v\; z"\; filenames="A20081001837200101.png,A20081001837200102.png"\; state="\{\{state\}\}">v</figure-callout>}}_z^{}},$ B is the inertia resistance coefficient, and k is the permeability of porous media, ρ B|v|v _xBe inertia loss item, β is the coefficient of thermal expansion of air, ρ ₀And T ₀Be respectively the reference value of atmospheric density and temperature.

Energy equation:

$C_e^{*}\frac{\&PartialD;T}{\&PartialD;t}=\frac{\&PartialD;}{\&PartialD;x}\left({\mathrm{\&lambda;}}_e^{*}\frac{\&PartialD;T}{\&PartialD;x}\right)+\frac{\&PartialD;}{\&PartialD;y}\left({\mathrm{\&lambda;}}_e^{*}\frac{\&PartialD;T}{\&PartialD;y}\right)+\frac{\&PartialD;}{\&PartialD;z}\left({\mathrm{\&lambda;}}_e^{*}\frac{\&PartialD;T}{\&PartialD;z}\right)-c_p\mathrm{\&rho;}(v_x\frac{\&PartialD;T}{\&PartialD;x}+v_y\frac{\&PartialD;T}{\&PartialD;y}+v_z\frac{\&PartialD;T}{\&PartialD;z})---\left(10\right)$

In the formula: C _e ^*, λ _e ^*Be dielectric layer equivalent volume thermal capacitance, equivalent coefficient of thermal conductivity.

3) roadbed and bottom soil layer district

These zones are solid area, and its equation of heat conduction is as follows:

$C_e^{*}\frac{\&PartialD;T}{\&PartialD;t}=\frac{\&PartialD;}{\&PartialD;x}\left({\mathrm{\&lambda;}}_e^{*}\frac{\&PartialD;T}{\&PartialD;x}\right)+\frac{\&PartialD;}{\&PartialD;y}\left({\mathrm{\&lambda;}}_e^{*}\frac{\&PartialD;T}{\&PartialD;y}\right)+\frac{\&PartialD;}{\&PartialD;z}\left({\mathrm{\&lambda;}}_e^{*}\frac{\&PartialD;T}{\&PartialD;z}\right)---\left(11\right)$

C in the formula _e ^*And λ _e ^*For the equivalent volume thermal capacitance and the equivalent coefficient of thermal conductivity of subgrade soil, relevant with temperature.

Adopt the method for numerical computations to find the solution to above each Region control equation group, the thermal field of any time that can obtain roadbed after build is finished.We have carried out comparative analysis to ever-frozen ground district high-grade highway broken stone slope protector roadbed, air chimney roadbed and broken stone slope protector and air-duct composite roadbed three kinds of road structure thermal field after build is finished method by this numbered analog simulation.Fig. 3～5 be respectively broken stone slope protector roadbed, air chimney roadbed and broken stone slope protector and air-duct composite roadbed after build is finished 50 on October 30, simulation ground temperature isogram.From Fig. 3～5 as can be seen: broken stone slope protector and air-duct composite roadbed cooling-down effect are best,-0.8 ℃ of isotherm has appearred in the roadbed bottom, next is the air chimney roadbed, roadbed bottom minimum temperature is-0.5 ℃, but 0 ℃ of isotherm seriously moves down at roadbed slope angle place, and this is very unfavorable to subgrade stability; The poorest is the broken stone slope protector roadbed, and its underpart frozen soil heats up significantly, and 0 ℃ of isotherm moves down into about 12.0m below the former natural surface in the roadbed center, and this will do great damage to roadbed.By above isollaothermic chart comparative analysis, we draw to draw a conclusion: this broken stone slope protector not only can actively reduce its underpart frozen soils temperature effectively with air-duct composite roadbed, and roadbed bottom frozen soils temperature is evenly distributed, successfully having solved broken stone slope protector roadbed middle part frozen soil upper limit seriously moves down, the relatively poor problem of air chimney roadbed slope angle place's cooling-down effect has improved frozen earth roadbed stability.

The beneficial effect of advantage of the present invention and generation is:

1, the present invention has made full use of the cooling effect of natural convection and the quick aeration-cooling characteristics of air chimney of broken stone slope protector, realization is to the cooling effect of roadbed bottom frozen soil, make it be in lower state of temperature, promote frozen soil upper limit, roadbed temperature of lower field is evenly distributed, solve because frost heave that seasonal active layer produces in frozen-thaw process and thaw collapse are given the destruction that roadbed brought;

2, the present invention need not any external impetus facility, and is pollution-free, preserves the ecological environment.And the piece rubble is drawn materials conveniently, and air chimney can transport on-the-spot directly laying to after factory process is finished, can not produce big artificial disturbance to frozen soil, can satisfy the specific (special) requirements of high temperature, hight-ice-content permafrost area high-grade highway engineering stability;

3, the present invention is simple in structure, and main material is piece rubble, concrete and reinforcing bar or PVC material, and cost is low, is easy to construction and safeguards that cooling-down effect and engineering stability are good, have application prospect preferably.

Description of drawings:

Fig. 1 is broken stone slope protector and air-duct composite roadbed schematic perspective view.

Fig. 2 is broken stone slope protector and air-duct composite roadbed horizontal section schematic diagram.

Fig. 3 broken stone slope protector roadbed is simulation on October 30, ground temperature isogram after build is finished 50.

Fig. 4 air chimney roadbed is simulation on October 30, ground temperature isogram after build is finished 50.

Fig. 5 broken stone slope protector and air-duct composite roadbed after build is finished 50 on October 30, simulation ground temperature isogram.

The specific embodiment:

Below in conjunction with accompanying drawing, will be described further again the present invention.

With reference to accompanying drawing 1～2, a kind of broken stone slope protector that utilizes natural cold energy and air-duct composite roadbed is at first with natural surface 4 compactings, filling roadbedly then banket 1, and at the roadbed horizontal air chimney 2 that 1 laid inside connects that bankets, and perpendicular to road-trend, the densification compacting; Air chimney 2 diameters are 0.5m, and the tube and tube axis spacing is 3 times of calibers, and the air chimney axis is 0.7m apart from natural surface 4; Broken stone slope protector 3 is dosed in the roadbed both sides, bank protection piece broken stone slope particle diameter is 10～30cm again, and horizontal breadth is 1.5m, and horizontal air chimney 2 runs through broken stone slope protector.

Its course of work can be described as: when winter, outside air temperature was low, the broken stone slope protector outside and upper temp are lower than the inboard, the outer top of inner air density is greater than interior bottom, under the effect of gravity and buoyancy lift, cool ambient air flows into from the broken stone slope protector bottom side, internal heat air come-up, and flowing of air brought outside " cold " in the roadbed into, simultaneously " heat " in the roadbed taken out of, realized cooling effect the roadbed side slope and the bottom soil body; When summer, ambient temperature was higher, the outer upper temp of broken stone slope protector was higher than interior bottom, and the outer top of atmospheric density is less than interior bottom, and air is in relative static conditions, and no convection current takes place.Air chimney crosses roadbed; realize change by quick ventilation to the surrounding soil temperature; because ever-frozen ground district average temperature of the whole year is lower than 0 ℃; and has the climatic characteristic that dry monsoon is big, wet monsoon is little; thereby air chimney has been realized the accumulation to the roadbed subzero temperature, reaches the purpose of protection bottom frozen soil.The present invention has made full use of the quick aeration-cooling characteristics of the cooling effect of natural convection and the air chimney of broken stone slope protector, both advantages is combined realize cooling effect to roadbed bottom frozen soil.

Claims (3)

1, a kind of broken stone slope protector and air-duct composite roadbed, the roadbed that it is characterized in that being equipped with on the natural surface (4) in compacting the densification compacting bankets (1), and roadbed (1) inside of banketing is covered with the horizontal air chimney (2) of perforation, and perpendicular to road-trend; Again broken stone slope protector (3) is dosed in the roadbed both sides, and horizontal air chimney (2) runs through broken stone slope protector (3).

2, a kind of broken stone slope protector according to claim 1 and air-duct composite roadbed is characterized in that air chimney (2) pipe diameter is 0.2～1.0m, and the tube and tube axis spacing is 2～3 times of calibers, and its axis is 0.5～4.0m apart from natural surface (4).

3, a kind of broken stone slope protector according to claim 1 and air-duct composite roadbed is characterized in that bank protection piece ballast grain sizes is 10～30cm, and horizontal breadth is 0.5～2.5m.

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