JPH0430005A - Freezing preventing method for road surface - Google Patents

Abstract

PURPOSE:To prevent the cracking on the road surface by burying a radiating pipe in the road surface and a heating pipe in the road floor to melt snow with hot water, storing heat with hot water when the road floor is at the freezing pint or below, and switching the radiating pipe and heating pipe according to the temperature. CONSTITUTION:A radiating pipe 7 and a road surface temperature detector 9 connected to a snowfall detector 8 are buried in the road surface made of a paving material 1, a roadbed 2 made of a granular material below it is provided in contact with the road floor 3 below, and a heating pipe 4 and a road floor temperature detector 6 connected to the snowfall detector 8 are installed on the boundary face or in the road floor 3. The detector 8 is connected to an automatic action panel 5, which switches a flow control valve 10 and operates a pump. When the road surface is cooled to 0 deg.C, the detector 8 detects it and directly sends a signal to the automatic action panel 5, the control valve 10 is switched, and hot water is fed to the heating pipe 4. The road floor 3 is warmed, heat is stored, and the freezing of the road floor 3 can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to roads and floors of roads, parking lots, precision machinery factories, freezers, liquefied natural gas terminals, etc. in snowy and cold regions, high mountainous regions, and coastal industrial areas. This paper relates to methods for preventing frost heaving damage that occurs on surfaces.

[Conventional technology]

Traditionally, frost heave has been a common phenomenon in cold regions.

When the temperature drops below 0℃ in winter, the pore water in the soil near the ground surface begins to freeze, and the frozen surface progresses downward into the soil over time. When water moves to a frozen surface or freezes, an ice layer is formed horizontally on the ground surface, water is absorbed from the unfrozen part to the frozen surface, and water in the soil freezes, causing the ground to swell. The phenomenon is frost heave. As a result, cracks form in the paved surfaces of roads, etc., and snowmelt water seeps into these cracks during the day, and at night, this water freezes and expands in volume, causing the cracks to become even bigger and wider, and finally to the road surface. The tortoiseshell-shaped cracks spread and the road surface becomes damaged.

However, in recent years, with the advancement of road lightning and snow removal technology, complete lightning removal and complete snow removal have become commonplace, so there is almost no snow on roads in snowy areas even in winter, and the road surface is constantly exposed to cold outside air, so there is always heat from the road surface. As a result, damage caused by frost heave has become common in snow-covered areas and high mountain areas. Moreover, damage caused by frost heave occurs not only on roads in snowy and cold regions, but also on the floors of precision machinery factories located in high mountain regions, large freezers in coastal areas, and underground of liquefied natural gas storage tanks, etc., and is urgently needed. countermeasures were desired.

In order to prevent such damage, measures to prevent frost heaving that have been taken so far include replacing the conventional surface up to the freezing depth in the area with sand or granular materials with a low moisture content, and For this purpose, we have adopted a replacement construction method that creates a frost heaving suppression layer, multiple insulation materials between the roadbed and the roadbed to prevent the heat from the subgrade from being transferred to the ground surface, and even a grid-like polymer resin material for the roadbed. Covering with a net The subbase material and the net work together to resist frost heaving, to ensure uniform frost heaving, to prevent local heave-up of the road surface, and to prevent the formation of tortoiseshell-shaped cracks that occur on the road surface. Attempts have been made, but they have not been able to completely prevent frost heaving.

[Problem to be solved by the invention]

The present invention was made in view of the above circumstances, and the heat of the roadbed is taken away from the ground surface, the roadbed cools and freezes, the frost heaving phenomenon occurs, the road surface swells, and cracks appear on the road surface. It prevents the cracks from expanding over time, causing tortoiseshell-shaped cracks to spread on the road surface and eventually causing damage to the road. It also prevents damage to the road and floor surfaces due to frost heaving, and is safe, easy to maintain, and durable. The purpose of this study is to provide a method to prevent frost heaving, which aims to create a road surface with frost.

[Means to solve the problem]

The present invention is a method for preventing frost heave on a road surface to achieve the above object, in which a heating pipe is buried in the road bed, and the temperature of the road bed is 0°C.
When the temperature drops below, hot water or antifreeze after heat exchange is passed through the heating tube, and when the road surface is cooled by cold outside air and heat is removed from the ground surface, hot water or antifreeze after heat exchange flows through the heating tube. This is a method to prevent the roadbed from freezing by warming the roadbed to store heat and resisting the cooling effect of the roadbed from the ground surface, thereby preventing cracks that occur on the road surface due to frost heaving.

In addition, heat dissipation pipes are buried in the road surface, and heating pipes are buried in the roadbed, and when it snows, hot water or antifreeze after heat exchange is passed through the heat dissipation pipes to melt the snow that falls on the road surface and prevent the road surface from freezing. When the temperature of the roadbed drops to 0℃ or less when there is no snowfall, hot water or antifreeze after heat exchange is passed through the heating pipe, and when the road surface is cooled by the cold outside air and heat is removed from the ground surface. , the hot water flowing in the heating pipe or the antifreeze liquid after heat exchange warms the roadbed and stores heat, and prevents the roadbed from freezing by resisting the cooling action of the roadbed received from the ground surface;
A method for preventing frost heave on a road surface, which prevents cracks from occurring on the road surface or the floor surface, and is characterized in that water flow to the heat radiation pipe and the heating pipe is appropriately switched according to the road surface temperature or the subgrade temperature. .

[Effect]

The road surface frost heaving prevention method according to the present invention is such that when the outside air cools down to below 0℃ for a long period of time, or cold wind continues to blow and heat is removed from the road surface, the underground heat continues to be removed from the ground surface, and eventually reaches a specified level. It is cooled down to the roadbed which is provided at a depth.
'C has been reached.

At this time, if hot water or antifreeze after heat exchange is passed through heating pipes installed in the subgrade to warm the subgrade and store heat, there is a subgrade with low thermal conductivity above the subgrade.

The heat from the hot water in the heating pipes or from the antifreeze after heat exchange is difficult to transfer upwards, effectively warming the subgrade and storing heat. This prevents frost heaving damage caused by freezing of the subgrade, and reduces the risk of damage to the road surface. Prevent cracks from occurring.

In addition, when heat dissipation pipes are buried in the road surface and heating pipes are installed in the roadbed, snowfall detectors installed on the ground can detect the presence or absence of snowfall.
The road surface temperature sensor detects the road surface temperature and extinguishes lightning on the road surface by passing hot water or antifreeze after heat exchange into the heat dissipation pipe, and also prevents the road surface from freezing.When the snow on the road surface is extinguished and the road surface dries, heat is radiated. Stop water flow into the pipe. Subsequently, the road surface continues to be exposed, and the heat underground is taken away from the road surface by cold outside air and cold wind, and the freezing temperature of 0℃ gradually decreases until it reaches the subgrade. An installed temperature sensor operates to switch the water flow control valve, and hot water or antifreeze after heat exchange is passed through heating pipes installed in the subgrade to warm the subgrade and store heat. At this time, because there is a roadbed with low thermal conductivity above the roadbed, the heat from the hot water in the heating pipes or the antifreeze after heat exchange is difficult to transfer upward, effectively warming the roadbed and storing heat. It can prevent frost heaving caused by freezing of the roadbed and prevent cracks from occurring on the road surface.

Furthermore, in spring and summer, when the road surface temperature rises above a predetermined temperature, the road surface temperature is detected and solar heat is collected by passing cold water into a heat radiation pipe buried in the road surface, and the heat radiation pipe is used as a heat collecting pipe. Warm water is created and stored in an aquifer deep underground using the aquifer's heat retention effect.Then, next winter, a snowfall detector installed on the ground detects snowfall. The road surface temperature sensor detects the road surface temperature, and the hot water stored in the deep underground aquifer or the antifreeze after heat exchange is passed through the heat dissipation pipes buried in the road surface to extinguish the road surface. In addition to using lightning, it also prevents road surfaces from freezing, and once the snow on the road surface is cleared and the road surface dries, water flow to the heat dissipation pipes is stopped. The road surface continues to be exposed, and the heat underground is taken away from the road surface by cold outside air and cold wind, and the freezing temperature of 0℃ gradually decreases until it reaches the subgrade. The temperature sensor activated and switched the water flow control valve.

Hot water stored deep underground or antifreeze after heat exchange is passed through heating pipes installed in the roadbed to warm the roadbed and store heat. At this time, because there is a roadbed with low thermal conductivity above the roadbed, the heat from the hot water in the heating pipes or the antifreeze after heat exchange is difficult to transfer upward, effectively warming the roadbed and causing frost heave due to freezing of the subgrade. This prevents cracks from occurring on the road surface. This collection of solar heat, storage of heat in aquifers, lightning extinguishing and antifreezing of road surfaces, and prevention of frost heaving on road surfaces by preventing freezing of roadbeds are repeated year after year.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic cross-sectional view showing a first embodiment of the present invention. In the figure, the road surface is made of a pavement 1 such as asphalt or concrete, and a roadbed 2 made of granular material is underneath. The lower surface of the dovetail roadbed is in contact with the subgrade 3, and a heating pipe 4 and a subgrade temperature detector 6 connected to an automatic operation panel 5 are installed at the boundary between the subgrade and the subgrade or within the subgrade.

In the first embodiment configured as described above, when the temperature of the subgrade drops to 0°C in winter, the subgrade temperature detector 6 detects the temperature of the subgrade 3, and the automatic operation panel 5 operates to control the temperature of the subgrade (not shown). The heat source pump is operated to pass hot water or antifreeze after heat exchange into the heating pipe 4 to warm the roadbed 3 and store heat to prevent the roadbed from freezing. Subsequently, when the temperature of the roadbed rises to a predetermined temperature in consideration of economy and energy saving, the operation of the facility is stopped by the action of the roadbed temperature detector 6 and the automatic operation panel 5. In addition, when the roadbed is heated by hot water flowing in the heating pipe or antifreeze after heat exchange, the roadbed is made up of a packed layer of granular material and has many voids, so its thermal conductivity is low. The heat of the antifreeze after heat exchange is difficult to be transmitted upwards, effectively warming and storing heat in the roadbed, and it is possible to prevent damage caused by frost heaving of the road surface or floor surface due to freezing of the roadbed.

Furthermore, the patent is not a patent that is characterized by the material, diameter, installation form, installation interval, installation depth from the ground surface, etc. of the heating pipes, but rather by the weather conditions of the region, soil conditions of the roadbed, economic efficiency, etc. The heating plate may be selected appropriately taking into consideration the following: In addition, a heating plate having a large number of water passage holes inside may be used instead of using a pipe, and the installation position of the heating pipe is preferably within the roadbed. It may be inside the roadbed or within the pavement.

In addition, if the heat source is groundwater, spring water from a tunnel, hot spring water, hot spring return hot water, heated water from boiler combustion, seawater, or factory wastewater, etc., if water is directly passed through the water, the corrosivity of these heat source water and various types of water may be affected. They may be appropriately selected and combined in consideration of the corrosion resistance of the heating tube.

In addition to the above-mentioned heat source problem, when the heat source is exhaust gas heat in a tunnel, waste heat after freezing a freezer, snow heat, vaporization heat of liquefied natural gas, etc., the temperature of each heat source Depending on the level, a heat exchanger or, in some cases, a heat pump may be used to raise the temperature to a desired temperature that contributes to freezing prevention and transmit it to the antifreeze, and the type and concentration of the antifreeze may also be selected appropriately.

In addition, although we have talked about hot water and antifreeze after heat exchange, heated air or compressed warm air may also be sent to the heating pipes, and in this case, problems due to water leakage from the heating pipes will not occur. Effective.

In addition, especially when groundwater is used as a heat source, groundwater with a temperature that reflects the annual average temperature of the area is generally obtained around 15m underground, and as the temperature goes deeper by 100m, it is approximately 3.
Water temperature increases by degrees Celsius, so in order to obtain groundwater at the desired temperature, the depth of groundwater intake should be determined by taking these factors into consideration.Furthermore, since groundwater and hot spring water are valuable natural resources, The cold water after anti-freezing is preferably returned underground from a separate well.
In addition, heat is collected using a heat exchanger using groundwater as a heat source.

When heat is transferred to the antifreeze on the secondary side, it is effective to install the heat exchanger inside the well because cooling by outside air does not occur and installation space is not required.

Furthermore, by inserting a steel mesh into the pavement, the effect of preventing cracks in the road surface due to frost heaving is further enhanced.

In addition to roads and parking lots, the present invention can also be installed on airport runways, piers, tennis courts, platforms, and ice skating rinks. In the case of ice skating rinks, it can be installed on the rink surface. It is also possible to use the waste heat from ice making as a heat source to warm the ground underground and prevent cracks from forming on the ice skating rink surface due to frost heave.

As described above in detail, the heating tubes, heat sources, heat exchangers, heat pumps, antifreeze, heated air, iron mesh, installation locations, etc. are the same in the second and third embodiments described below.

(Second Embodiment) FIG. 2 is a schematic cross-sectional view showing a second embodiment of the present invention. In the figure, the road surface is made up of a pavement 1 and has a heat dissipation pipe 7 inside and a road surface temperature sensor connected to a snowfall detector 8. A detector 9 is buried, and there is a roadbed 2 made of granular material below it, the lower surface of the roadbed is in contact with the roadbed 3, and a heating pipe 4 and a snowfall detection device are installed at the interface between the roadbed and the roadbed or in the roadbed. A subgrade temperature sensor 6 connected to the subgrade sensor 8 is installed. The snowfall detector 8 is also connected to an automatic operation panel 5 so as to switch the water flow control valve 10 and operate a pump (not shown).

In the second embodiment configured as described above, when the road surface temperature drops to 0°C in winter and the snowfall detector detects snowfall, the automatic operation panel operates and switches the water flow control valve to control the heat radiation buried in the road surface. Hot water or antifreeze after heat exchange is made to flow in the pipe, and a pump (not shown) is activated to send the hot water or antifreeze after heat exchange into the heat radiation pipe, which melts snow on the road surface and also prevents the road surface from freezing. . In this way, the snow on the road surface is extinguished, and when the road surface dries, the automatic operation panel is activated by signals from the road surface temperature sensor and the snowfall detector, and the operation of the heat source pump is stopped.

In such conditions, the road surface is exposed, and heat is taken away from the ground surface by cold outside air and cold wind, and the freezing temperature of 0℃ gradually decreases, until the temperature of the roadbed reaches O"C. Then, the subgrade temperature sensor sends a signal to the snowfall detector or directly to the automatic control panel to switch the water flow control valve.
The hot water or the antifreeze after heat exchange is made to flow toward the heating pipe, and a pump (not shown) is activated to send the hot water or the antifreeze after heat exchange into the heating pipe to warm the subgrade and store heat. Prevent freezing. Subsequently, when the temperature of the roadbed rises to a predetermined temperature in consideration of economy and energy saving, the operation of the facility is stopped by the action of the roadbed temperature detector and the automatic operation panel.

When the roadbed is heated by hot water flowing in the heating pipe or antifreeze after heat exchange, the roadbed is made up of a packed layer of granular material and has many voids, so its thermal conductivity is low. The heat from the antifreeze after replacement is difficult to transfer upward, effectively warming and storing heat in the subgrade, thereby preventing damage from frost heaving on the road surface due to freezing of the subgrade.

(Third Embodiment) FIG. 3 is a schematic cross-sectional view showing a third embodiment of the present invention. In the figure, the road surface is made up of a pavement 1 and has a heat dissipation pipe 7 inside and a road surface temperature sensor connected to a snowfall detector 8. A detector 9 is buried, and there is a roadbed 2 made of granular material below it, the lower surface of the roadbed is in contact with the roadbed 3, and a heating pipe 4 and a snowfall detection device are installed at the interface between the roadbed and the roadbed or in the roadbed. A subgrade temperature sensor 6 connected to the subgrade sensor 8 is installed. The snowfall detector 8 is also connected to the automatic operation panel 5 to control the switching of the water flow control valves 10.10' and the operation of the water pumps 11.11'. Further, each of the water flow control valves 10 and 10' extends a pipe line to a water pump 12 and 12', each of which has a water pump 11 and 11' connected to its tip.
Injection pipes 13 and 13' are connected to one of the pipes, respectively, and are installed in water in well A and well B, respectively.

In the third embodiment configured in this way, spring, summer,
In the fall, when the road surface is heated by solar heat and the temperature of the road surface becomes higher than the pumping temperature of groundwater in the area, an automatic operation panel will operate and groundwater will be pumped up from well A by pump 11 and buried within the road surface. This underground water or antifreeze fluid circulating on the secondary side of a heat exchanger (not shown) is sent into the heat sink pipes to collect solar heat and create hot water. At this time, the heat dissipation tubes buried in the road surface act as solar heat collection tubes. The hot water created in this way is injected back into the deep underground aquifer 14' from the well B through the injection pipe 13'.
The hot water area within the aquifer is gradually expanded, and heat is stored and stored deep underground by utilizing the aquifer's heat retention effect. Subsequently, in the next winter, when the road surface temperature drops to 0°C and the snowfall detector 8 detects snowfall, the automatic operation panel 5 operates, switches the water flow control valves 10° and 10', and switches the water pump 11' from the well B to the water pump 11'. Groundwater with a temperature higher than normal groundwater temperature is pumped up, and hot water or antifreeze after heat exchange with a heat exchanger (not shown) is sent into the heat radiation pipes buried in the road surface, which melts the snow on the road surface. It also prevents freezing.

In this way, when the snow on the road surface is extinguished and the road surface dries, the automatic operation panel is activated by signals from the road surface temperature sensor and the snowfall sensor to stop the operation of the water pump 11'.

In such conditions, the road surface is exposed, and heat is taken away from the ground surface by cold outside air and cold wind, and the freezing temperature level of 0℃ gradually decreases until the temperature of the roadbed reaches 0℃. When the subgrade temperature sensor reaches the temperature, the subgrade temperature sensor sends a signal to the snowfall detector or directly to the automatic operation panel, and the water flow control valve 10°10' is switched to supply hot water to the heating pipe 4 or to a heat exchanger (not shown). The antifreeze solution after heat exchange is delivered to warm the subgrade to prevent it from freezing.Then, when the subgrade rises to a predetermined temperature in consideration of economic efficiency and energy saving, the antifreeze solution is automatically operated with the subgrade temperature detector. The operation of the facility is stopped due to the operation of the panel.

When heating with hot water flowing in the heating tube or antifreeze after heat exchange, the roadbed is made up of a packed bed of granular material and has many voids, so the thermal conductivity is low. The heat of the antifreeze is transmitted upwards, effectively warming the roadbed and storing heat, thereby preventing damage from frost heaving on the road surface due to freezing of the subgrade.

In addition, in this embodiment, solar heat collection and heat storage in an aquifer in the spring, summer, and autumn, as well as road surface lightning extinguishing and freezing prevention in the winter, as well as frost heaving prevention, are repeated every year.

〔Effect of the invention〕

Since the present invention has the configuration as described above, it has the following effects.

The road surface frost heaving prevention method according to the present invention is such that when the temperature of the roadbed drops below a predetermined temperature, hot water or antifreeze after heat exchange is passed through heating pipes installed in the roadbed to effectively heat the roadbed. Since heat is stored in the floor and the roadbed is maintained at a constant temperature, it is possible to prevent the roadbed from freezing and prevent cracks from occurring on the road surface due to frost heaving.

At this time, since the roadbed beneath the road surface is made up of a packed layer of granular materials and has many voids and low thermal conductivity, cooling from the ground surface is achieved by installing heating pipes in the roadbed located at the bottom of the roadbed. The action is difficult to reach the subgrade, and the heat of the hot water flowing in the heating pipe or the antifreeze after heat exchange is effectively stored, and the subgrade is effectively heated and stored against the cooling action received from the ground surface. Since the roadbed is maintained at a constant temperature, it is possible to prevent the roadbed from freezing and prevent the occurrence of cracks in the road surface due to frost heaving.

In addition, the flow of hot water and antifreeze after heat exchange is automatically switched between the heat dissipation pipes buried in the road surface and the heating pipes installed in the road bed, depending on snowfall conditions and road bed temperature. In addition to extinguishing snow, we also prevent road surfaces from freezing, and
It can prevent frost heaving due to freezing of the roadbed and prevent cracks from occurring on the road surface.

In addition, heat dissipation pipes buried in the road surface act as solar heat collection pipes in the spring, summer, and fall to store hot water deep underground, and this warm water is pumped up in the winter to collect heat from the sun's heat in the spring, summer, and fall. The water is sent to heating pipes installed in the floor, which are switched as appropriate depending on snowfall conditions and subgrade temperature, which effectively extinguishes road surface lightning with a small amount of water, and also prevents road surfaces from freezing.
In addition, since the temperature of the roadbed is kept constant, it is possible to prevent the roadbed from freezing and prevent cracks from occurring on the road surface due to frost heaving.

Furthermore, when constructing roads in snow-covered areas or high-altitude mountainous areas, an artificial frost heaving suppression layer was previously installed under the roadbed, but heating pipes were installed within the roadbed to prevent this heating. Warm water and antifreeze after heat exchange are passed through the pipes to maintain the roadbed at a constant temperature to prevent frost heave. This eliminates the need for a frost heave suppression layer, reducing construction costs and construction time, and preventing cracks on the road surface. Since this does not occur, the lifespan of the facility can be extended.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the first embodiment of the present invention, and the second
The figure is a schematic sectional view showing a second embodiment of the invention, and FIG. 3 is a schematic sectional view showing a third embodiment of the invention. 1... 3... 5... 6... 7... 8... 9... 10, 1 11, 1 12, 1 2... Roadbed. 4...Heating pipe, road surface (paving body), roadbed, automatic operation panel, subgrade temperature detector, heat radiation pipe, snowfall detector, road surface temperature detector, 0'...water flow control valve. 1'... Lifting pump, 2'... Lifting pipe, 13° injection pipe, 14°14'... Aquifer. Agent Tetsuro Abe

Claims (3)

[Claims] (1) Heating pipes are buried in the roadbed, and when the temperature of the roadbed drops below 0°C, hot water or antifreeze after heat exchange is passed through the heating pipes, and the road surface is cooled by cold outside air. When heat is removed from the ground surface, the hot water flowing in the heating pipe or the antifreeze liquid after heat exchange warms the subgrade and stores heat, and prevents the subgrade from freezing against the cooling action of the subgrade received from the ground surface. A road surface frost heaving prevention method characterized by preventing cracks occurring on a road surface due to frost heaving of a roadbed. (2) A heat dissipation pipe is buried in the road surface, and a heating pipe is buried in the road bed, and when it snows, hot water or antifreeze after heat exchange is passed through the heat dissipation pipe to melt the snow that falls on the road surface, and to melt the snow that falls on the road surface. When the temperature of the roadbed drops to below 0°C when there is no snowfall, hot water or antifreeze after heat exchange is passed through the heating pipe, and the cold outside air cools the road surface and removes heat from the ground surface. When the water is taken away, the hot water flowing in the heating pipe or the antifreeze after heat exchange warms the subgrade and stores heat, and prevents the subgrade from freezing against the cooling effect of the subgrade received from the ground surface. A method for preventing frost heave on a road surface, which prevents cracks occurring on a road surface due to frost heave, and is characterized in that water flow to the heat radiation pipe and the heating pipe is switched depending on the road surface temperature or the subgrade temperature. (3) The road surface according to claim 1 or 2, characterized in that solar heat collected in the summer is converted into hot water, stored in an aquifer deep underground to keep it warm, and the hot water is taken out in the winter. How to prevent frost heaving.