JPH089222Y2 - Ground freezing heat pipe - Google Patents

Description

[Detailed description of the device] Industrial field of application This device is one of the ground improvement methods used for excavation work on tunnels, shafts, etc., and is used for the ground freezing method for freezing soft ground. It is about heat pipes.

Conventional technology When excavating soft ground or other easily collapsible ground during tunnel or root cutting work, ground improvement work is performed prior to the excavation work in order to prevent collapse of the excavation wall. Be done. In this ground improvement work, various ground improvement materials such as cement milk and water glass are generally injected into the soil to solidify, and after the ground in the planned excavation area is impregnated with water, A ground freezing method is used in which water is cooled and the water is frozen together with the ground. In this ground freezing method, a heat pipe is often used as a means for cooling the ground. In this case, the heat pipe is such that the evaporating section side is buried in the ground to be excavated, the condensing section side is extended to the outside such as the surface of the earth, and the portion extended to the outside is cooled by the cooling device. It has become.

Therefore, in the heat pipe whose condenser part side is cooled by the cooling device, the enclosed working fluid absorbs the underground heat and evaporates in the evaporating part whose temperature is higher than that of the condensing part. Moves to the condensing part, radiates heat in the low temperature condensing part, condenses back to the liquid phase, and returns to the evaporating part. And
By repeating the above cycle, the heat in the ground is pumped out, the ground is cooled to below freezing, and the water contained in the ground is frozen. As a result, the soft ground is strengthened by freezing, preventing collapse during excavation. After the heat pipe for cooling is pulled out, the part where the excavation is completed is frozen while the ground is frozen, and the ground in front of the excavation direction is frozen while the excavation wall is being reinforced by supports and concrete retaining walls. , Further excavation.

However, in the case of the heat pipe used in the conventional ground freezing method described above, the heat pipe is directly inserted into the hole formed by the drilling machine in the ground to be excavated. When the cooled ground freezes, the heat pipe also freezes inside the hole where it is inserted, making it difficult to remove.In addition, if the frozen heat pipe is forcibly pulled out by mechanical force, etc., it may be damaged. However, there was a problem that the conversion rate of the heat pipe was lowered due to bending.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a ground freezing heat pipe that can be easily extracted while the ground is frozen.

Means for Solving the Problems As a means for solving the above problems, a ground freezing heat pipe according to the present invention comprises a heat pipe main body having a cooling means at an end on the condensation part side, and an evaporation part of the heat pipe main body. And a casing into which a lubricant that does not solidify within the operating temperature range is injected into a gap with the heat pipe body.

With the above-mentioned configuration, the ground freezing heat pipe of the present invention is inserted into the hole drilled in the ground through the casing, and the operating temperature range is between the heat pipe body and the casing. It is filled with a lubricant that does not solidify inside.

Therefore, at the time of cooling, when the condensing part of the heat pipe body is cooled, the heat in the ground is transferred to the evaporating part of the heat pipe body via the casing and the lubricant, and is heated to evaporate the working fluid. And the vapor of the evaporated working fluid is
The cooling means moves to the condensing part cooled to radiate heat, condenses and returns to the liquid-phase working liquid.

In this way, the latent heat of vaporization held by the vapor of the hydraulic fluid is released at the condensing part, so that the heat in the ground is pumped out to cool the ground around the heating part of the heat pipe body, Freeze the water contained in. At this time, even if the ground around the heat pipe body freezes, the heat pipe body does not solidify.Because the heat pipe body is inserted into the casing filled with lubricant, the heat pipe body does not freeze and the heat pipe body does not come off. , Can be easily pulled out.

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

The ground freezing heat pipe has a condensable hydraulic fluid sealed therein and a heat pipe body 1 having a cooling unit 2 attached to a condenser portion 1a (left end in FIG. 1) at one end, and the heat pipe body. 1 has a bottomed cylindrical casing 3 into which the evaporation portion 1b side is inserted, and a cap 4 that liquid-tightly closes the open end (left end in FIG. 1) of the casing 3 with the heat pipe body 1 inserted. Further, the casing 3 is filled with the silicone oil 5 as a lubricant that does not solidify within the operating temperature range at the time of construction. In the casing 3, a lubricant injection pipe 6 has one end 6a disposed near the bottom of the casing 3 and the other end penetrating the cap 4 and extending outside the casing 3. There is.

Next, the operation of this embodiment configured as described above will be described.

Prior to the excavation work, the soil quality of the area to be excavated is examined, and when the ground is soft and there is a risk of collapse in the uncut area, the ground freezing work using this ground freezing heat pipe is performed. In the construction work, first, the insertion holes H are formed at predetermined intervals in the ground to be excavated by a drill or the like. Insertion hole H in this case
The interval is determined by the capacity of the ground freezing heat pipe to be used. If the cooling capacity is large, the interval is wide, and if the cooling capacity is not so large, the interval is set narrow. In addition, check the water content of the ground to be excavated, and if the water content is insufficient, supply water so that sufficient strength can be obtained by freezing.

Then, the casing 3 is first inserted into the insertion holes H formed at predetermined intervals, and then the heat pipe 1 having the cap 4 and the injection pipe 6 mounted therein is inserted into the casing 3. Next, with the cap loosened, silicone oil 5 is press-fitted from the extended end of the injection pipe 6 to fill the gap between the casing 3 and the heat pipe body 1 from the bottom side, and from the open end of the casing 3. When the silicone oil 5 is filled until it overflows, the open end of the casing 3 is closed by the cap 4.

After the insertion of the heat pipe body 1 into each insertion hole H and the filling of the silicone oil 5 are completed, the heat pipe body 1
When the condensing part 1a is cooled by the cooling device 2, the heat in the ground is pumped out by the heat pipe body 1 and the ground T around the casing 3 in which the heat pipe body 1 is inserted is frozen. At this time, since the silicone oil 5 is filled in the gap between the casing 3 and the heat pipe body 1 loosely inserted therein, the heat transfer is good and the surrounding ground T is efficiently cooled. It can be frozen.

When the heat pipe body 1 is extracted after excavation and supporting work of the frozen portion are completed, the cap 3 is loosened and the heat pipe body 1 is pulled out, and the casing 3 freezes on the inner surface of the insertion hole H. Even when the heat pipe body 1 is pulled out, the heat pipe body 1 inserted into the casing 3 is filled with the silicone oil 5 that does not freeze and the injection pipe 6 is inserted up to near the bottom of the casing 3. When a negative pressure is generated on the bottom side in the casing 3, the silicone oil 5 in the injection pipe 6 is sucked, and air flows in through the injection pipe 6, resulting in easy extraction from the casing 3. be able to.

Therefore, when the heat pipe body 1 is pulled out, the heat pipe body 1 is not damaged, so that the diversion rate of other heat pipe bodies and accessory parts excluding the casing is significantly improved.

In addition to silicone oil, ethylene glycol or the like is suitable as the lubricant that does not solidify.

Effects of the Invention As described above, the ground freezing heat pipe of the present invention is loosely fitted to the heat pipe body having the cooling means at the end on the condenser side and the outer periphery on the evaporator side of the heat pipe body. Since it has a casing and the gap between the casing and the heat pipe body is filled with a lubricant that does not solidify within the operating temperature range at the time of construction, the heat pipe body will not freeze and become stuck, so workability is improved. Along with the improvement, the conversion rate of the heat pipe body is significantly improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of this invention. 1 ... Heat pipe main body, 1a ... Condensing part, 1b ... Evaporating part, 2 ... Cooling device, 3 ... Casing, 4 ... Cap, 5 ... Silicon oil, 6 ... Injection pipe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Masataka Mochizuki 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. Shimizu Construction Co., Ltd. (56) Reference JP-A-62-112811 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A heat pipe body having a cooling means at its end on the condenser side, and a heat pipe body which is loosely fitted on the outer periphery of the heat pipe body in the operating temperature range in a gap between the heat pipe body and the heat pipe body. And a casing into which a lubricant that does not solidify is injected.