Title:
GROUND FREEZING SAMPLING METHOD AND DEVICE
Document Type and Number:
Japanese Patent JP2670991
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To reduce the heat loss of a low temperature fluid and form a columnar freezed-soil at the periphery of a cooling pipe, by making the relative position freely changeable in the vertical direction of the injection opening made in the cooling pipe for the low temperature fluid and the discharge opening.
SOLUTION: A main cooling pipe 3 is installed in a boring hole and a sampling position 2 is provided in the freezing soil area 11 formed concentrically against the pipe and also a sub-cooling pipe 4 is installed in a specified distance from the main cooling pipe 3 at the upstream side of the underground water. The sub-cooling pipe 4 is provided with a sub- injection opening and a sub-exhaust opening connected to an exhaust valve 10 in the main cooling pipe line. The injection opening 15 at the front end of the injection pipe 14 is extended to the nearby position of the bottom of the main cooling pipe 3 and the valve 10 is changed over to connect to the exhaust pipe 8 having an exhaust opening near the underground water level and the exhaust thereof is connected to the sub-injection opening of the sub-cooling pipe 4. The upper end of the injection pipe 14 is connected to an injection controller for liquid nitrogen to keep a steady injection state. The valve is changed over to discharge the exhaust gas from the exhaust opening at the lower part of the main cooling pipe at a proceeding time of freezing after a specified time and the injection volume of liquid nitrogen is increased to freeze a necessary area of a sand and gravel layer.
Inventors:
Sakai Uno
Toshiro Okamoto
Toshiro Okamoto
Application Number:
JP20281295A
Publication Date:
October 29, 1997
Filing Date:
July 17, 1995
Export Citation:
Assignee:
Foundation Ground Consultants Co., Ltd.
CENTRAL RESEARCH INSTITUTE OF ELECTRIC POWER INDUSTRY
CENTRAL RESEARCH INSTITUTE OF ELECTRIC POWER INDUSTRY
International Classes:
E02D1/04; E02D3/115; (IPC1-7): E02D1/04; E02D3/115
Domestic Patent References:
| JP35512A | ||||
| JP5230824A |
Attorney, Agent or Firm:
Kiyoshi Minoura