US 12,359,392 B1Granted

Thermosyphon foundation, method of calculating cold conductivity enhancement coefficient and method of cold conductivity enhancement thereof

AssigneeCccc First Highway Consultants Co., Ltd.

InventorsLong Jin, Yuanhong Dong, Binhua Hu, Jianbing Chen, Pan Chen, Jinbao Zhang, Liguo Zhao, Wansheng Pei, Xiaoliang Yao

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Abstract

The invention provides a thermosyphon foundation, a method of calculating cold conductivity enhancement coefficient and a method of cold conductivity enhancement thereof. The cold conductivity enhancement coefficient is obtained by using parameters including freezing index, latent heat of soil thawing, thermal resistance of pre-buried hole without injection of a cold conductivity enhancement medium, thermal resistance of cold conductivity enhancement mass or the like, and by using formulas for calculating the cooling radius of the thermosyphon without injection of a cold conductivity enhancement medium and the cooling radius of the thermosyphon after injection of a cold conductivity enhancement medium. The invention determines whether to proceed with subsequent construction by using the cold conductivity enhancement coefficient, and achieves cold conductivity enhancement for the thermosyphon foundation by using the method of cold conductivity enhancement.

A method of cold conductivity enhancement for thermosyphon foundation, comprising the steps of

drilling a pre-buried hole in the foundation:
injecting a cold conductivity enhancement medium with a cold conductivity enhancement coefficient K>1 into the pre-buried hole and then inserting a thermosyphon into the pre-buried hole, or inserting the thermosyphon into the pre-buried hole and then injecting the cold conductivity enhancement medium with the cold conductivity enhancement coefficient K>1 between the thermosyphon and the pre-buried hole;
and
forming the cold conductivity enhancement medium into a cold conductivity enhancement mass and filling a gap formed between the thermosyphon and the pre-buried hole;
calculating the freezing index Fl based on meteorological data;
based on geological parameters, calculating the latent heat of soil thawing QL by using Equation QL=L·pd·w, and calculating the thermal resistance R0 of a pre-buried hole without injecting a cold conductivity enhancement medium by using Equation
R
0
=
ln
⁢
d
d
0
2
⁢
π
⁢
λ
0
⁢
l
,
wherein the cold conductivity enhancement medium is used for filling the pre-buried hole to form a cold conductivity enhancement mass, as well as for filling the gap formed between the thermosyphon and the pre-buried hole, the geological parameters include the dry density of soil pa, the water content w and the initial thermal conductivity λ0 of the pre-buried hole, where L is the latent heat of phase transition, d is the diameter of the pre-buried hole, do is the diameter of the thermosyphon, and I is the depth of the pre-buried hole;
calculating the initial thermal conductivity λ0 of the pre-buried hole by using Equation λ0=λαε·λs(1−ε), where λa is the thermal conductivity of air, λs is the thermal conductivity of the medium within the hole, and ε is the porosity;
based on the cold conductivity enhancement medium, calculating the thermal resistance Rh of the cold conductivity enhancement mass by using Equation
R
h
=
ln
⁢
d
d
0
2
⁢
π
⁢
λ
h
⁢
l
,
where λh is the thermal conductivity of the cold conductivity enhancement mass;
calculating the cooling radius rf0 of the thermosyphon without injection of the cold conductivity enhancement medium by using Equation
FI
=
Q
L
·
[
π
⁢
L
⁡
(
R
a
+
R
0
)
·
(
r
f
⁢
0
2
-
(
d
2
)
2
)
+
r
f
⁢
0
2
4
⁢
λ
·
(
ln
⁢
2
⁢
r
f
⁢
0
d
-
1
)
+
d
2
16
⁢
λ
]
and calculating the cooling radius rf of the thermosyphon after injection of the cold conductivity enhancement medium by using Equation
FI
=
Q
L
·
[
π
⁢
L
⁡
(
R
a
+
R
h
)
·
(
r
f
2
-
(
d
2
)
2
)
+
r
f
2
4
⁢
λ
·
(
ln
⁢
2
⁢
r
f
d
-
1
)
+
d
2
16
⁢
λ
]
,
where Ra is the thermal resistance of the thermosyphon, λ is the thermal conductivity coefficient of soil, Rh is the thermal resistance of the cold conductivity enhancement mass;
and
calculating the cold conductivity enhance coefficient K by using Equation K=rf/rf0.

163 more elements

Abstract

Claims4