Abstract: A road surface is warmed by means of a two-phase thermosyphon with an easily vaporizable liquid partially filling a sealed container. A portion of the container serves as a condenser and another portion as an evaporator. If at least a portion of the evaporator is above the boiling point of the liquid, the liquid will boil and the vapor will rise into the condenser part of the thermosyphon, and if the condenser part is in an environment below the condensing temperature of the vapor, the vapor will condense, thereby radiating heat and warming the surrounding environment. The condenser is elongated and installed underground so as to lie closely beneath the road surface. A thermally insulating layer is provided below the condenser part so as to more efficiently utilize the radiated heat. The evaporator may be of a double-tube structure such that the liquid can flow through the entire length thereof even if these tubes include rising and falling sections.

Abstract: A thermosyphon for removing heat from a permafrost foundation is composed of a sealed container containing an easily vaporizable liquid. The container has a condenser part, which is exposed to temperatures below the condensation temperature of the liquid, and an evaporator part in which the liquid is intended to boil. The evaporator part is of double-tube structure with a supply tube and a return tube connected to each other at a point distal from the condenser part. The return tube has a riser with an opening at one end which is inside the supply tube and has a much smaller cross-sectional area than the supply tube around it. The tubes may have both rising and falling sections but the opening of the riser is sufficiently higher than these sections of the tubes such that the hydrostatic pressure causes the liquid in the evaporator part to flow from the supply tube into the return tube as the liquid forms bubbles in the evaporator part and overflows from the riser opening.

Abstract: A device for testing the loading of a test pile extending downwardly into the ground. The device includes a reaction pile axially disposed inside the test pile and a reference pile axially disposed inside the reaction pile. The reaction pile extends further into the ground than the test pile and the reference pile extends further into the ground than the reaction pile. A loading device simultaneously exerts a downward force on the test pile and an upward reaction force on the reaction pile such that the test pile moves downwardly, and a laser distance measurement system, attached to the test pile and extending axially therewith, also moves downwardly. The laser distance measurement system resides in a test chamber defined by a shroud circumscribing the test device and secured to the top of the test pile so as to move downwardly therewith.

Abstract: A modular pile unit and method of using same in which a plurality of small thermal piles are rigidly interconnected in a symmetrical array by interconnecting heat dissipation fins at the upper ends of the piles. A sleeve in one embodiment can be added to such an integral modular pile unit or, in another embodiment, can be added to an individual thermal pile to increase the effective diameter of the pile unit or the individual pile along a length extending into the permanently frozen region of the soil.