JPS61275383A - Method of improving thermal conductivity of soil - Google Patents

Abstract

PURPOSE:To enable feeding of a large amount of thermal energy into soil in a short period of time, by injecting a thermally conductive substance having a high thermal conductivity into a predetermined soil. CONSTITUTION:An injecting pipe 5 is inserted into a predetermined soil 1. A fluid contg. a powdery, thermally conductive substance (e.g.; Al) 4 having a high thermal conductivity is injected into the soil 1 through a pump 7 to disperse a larger amount of the thermally conductive substance throughout pores of the soil 1, thereby forming soil 3 having excellent thermal conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial field of application This invention is directed to the freezing of soil in the freezing method of civil engineering work.
The present invention also relates to a highly efficient method for thawing frozen road surfaces or melting snow on road surfaces. (2) Conventional technology Conventionally, when constructing a tunnel or constructing a concrete foundation for a building in soft soil that contains large amounts of groundwater, seawater, etc., a certain amount of soil is frozen to prevent groundwater or seawater from flowing into the excavated hole. After that, construction work was carried out.

In the case of the freezing method, a frozen pipe is inserted into the treated soil that is being excavated in tunnel construction, and the treated soil is cooled by supplying and circulating a refrigerant or coolant through the frozen pipe.

In addition, in order to melt the snow falling on the road surface or thaw the frozen road surface, high-temperature pipes are installed underground under the road surface, and hot water from factories and hot springs are connected to the pipes. The soil was heated by supplying hot water, etc.

When thawing frozen roads, high-temperature pipes were buried deep underground to prevent the weight of vehicles from being affected by objects.

(3) Problems to be solved by the invention Since soil has a lower thermal conductivity than metals, even if treated soil is cooled using a cryogenic coolant such as LNG, it will take a long time before the soil freezes. The process required a long time, and the area of frozen treated soil around the frozen pipe was relatively small.

Similarly, because the high-temperature pipes under the road surface are far from the road surface, or because the soil has low thermal conductivity, thawing frozen road surfaces requires a high temperature and large amount of heat source, which takes time. .

Furthermore, when a heat source of not very high temperature is supplied into the high-temperature pipe, the number of high-temperature pipes buried under the road surface must be increased in order to secure the amount of heat.

The object of the present invention is to eliminate these drawbacks and provide a method for efficiently improving the thermal conductivity of soil that is thawed using frozen acid.

(4) Means for Solving the Problems In order to achieve this objective, the present invention injects and mixes a highly thermally conductive material with high thermal conductivity into predetermined soil to be subjected to freezing and thawing processes to conduct thermal conduction of the soil. This is a higher rate.

(5) Functional Because a highly thermally conductive material with high thermal conductivity is injected and mixed into the soil, thermal energy from the heat source pipe can be quickly and efficiently conducted to the specified range, and processing such as freezing and thawing can be carried out. can.

(6) Embodiment To explain the present invention using drawings, FIG. 1 shows an embodiment in which the present invention is used when constructing a tunnel using the freezing method.

(1) shows soil, (2) shows a tunnel, and (3) shows frozen treated soil that is frozen using a freezing pipe (6) for tunnel construction. (4) is a highly thermally conductive material injected into the voids of the frozen treated soil (3) using the injection pipe (5). When excavating the soil (1) using the freezing method and then excavating the tunnel, the predetermined position that will be frozen from now on is Insert the injection pipe (5) into the By adding a powdered high heat conductive substance (4) with high thermal conductivity to the fluid such as air sent from the pump (7) through the injection pipe (5), and utilizing the transfer energy of the fluid, high heat can be generated. A conductive material (4) is injected into the soil (1). The highly thermally conductive material (4) is powder of aluminum, iron, copper, etc., and each can be used alone or in a mixture. Then, by injection from the injection pipe (5), the soil (1
) A large amount of powder is dispersed in the voids of the frozen soil (3), which has a much better thermal conductivity than ordinary soil. It is distributed in such a way that the individual powders are interconnected, just like a sintered alloy with internal voids. A freezing vibrator (6) is inserted into the frozen treated soil (3) in this state, and a coolant such as LPG is supplied and circulated within the freezing vibrator (6), but the effect is the same even if a heat pipe is used. be.

As a result, low-temperature energy is transmitted with almost the same conductivity as the high thermal conductivity material (4), and the water contained in the frozen soil (3) starts freezing from around the freezing vibrator (6). Then, by spreading to the entire area of the frozen treated soil (3), the frozen treated soil (3) and the surrounding soil (1) containing a lot of moisture
A wall of ice forms. This prevents surrounding moisture from flowing into the tunnel under construction.

FIG. 2 shows an embodiment in which the present invention is used to thaw ice or melt snow on the road surface (11). (16) shows a high-temperature pipe buried under the road surface (12) of the road (11), and the heat-treated soil (13) that conducts the thermal energy from the high-temperature pipe (16) to the road surface (12) is made of a highly thermally conductive material. A high-temperature pipe (16) such as a heat pipe installed at a predetermined position on the road (11), in which (14) is uniformly mixed, is a thermally conductive material containing a high thermal conductivity material (14) such as aluminum, iron, copper, etc. Bury in high soil. At that time, soil is layered so that the high-temperature pipe (16) will not be affected even if a heavy object such as a vehicle passes through it, and a layer of heat-treated soil (13) is placed on the high-temperature pipe (16). High thermal conductivity material (
14) is distributed in the heat-treated soil (13) in the same state as explained in the above-mentioned freezing method, so the high-temperature pipe (
By flowing hot spring water or high-temperature waste water from a factory into the soil (16), the thermal energy is conducted to the road surface (12) through the heat-treated soil (13), thawing the frozen road surface or thawing the road surface (12).
) Melt the snow on top. (7) Effects of the invention When the present invention is applied to the freezing method, the thermal conductivity of the frozen soil is almost the same as that of the metal powder it contains;
It can supply a large amount of thermal energy quickly and in a short period of time.
This allows the soil to be frozen over a wider area.

Furthermore, when the present invention is applied to road surface heating, since the heat-treated soil has high thermal conductivity, frozen road surfaces can be quickly thawed or snow on road surfaces can be melted, and high-temperature pipes such as heat pipes can be heated deeply. Since it can be buried, the safety of high-temperature pipes is further enhanced. Furthermore, since a large amount of thermal energy can be supplied in a short period of time, the number of buried high-temperature pipes can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view when the present invention is applied to tunnel construction, and FIG. 2 is a sectional view when the invention is applied to road surface heating.

Claims (1)

[Claims] A method for improving the thermal conductivity of soil, which is characterized by injecting and mixing a highly thermally conductive substance with high thermal conductivity into a predetermined soil that conducts thermal energy.