| 摘要 |
PROBLEM TO BE SOLVED: To improve a conventional method and apparatus for forming a sand pile through the feeding of compressed air into a casing pipe, in that they cannot properly cope with various conditions of the ground, leading to the fear that sand may be blown around or that a cavity for forming the sand pile may collapse. SOLUTION: An end lid 12 mounted at the end of the casing pipe 11 includes an end lid case 13 approximately in the form of a truncated cone, a ball valve 16 vertically movably enclosed in the end lid case 13, and a valve seat part 14 with which the ball valve 16 makes contact to close the interior of the end of the casing pipe 11. An earth pressure sensor S1 for measuring earth pressure around the end lid case is provided on the outside of the end lid case 13 and a pressure sensor S2 for measuring air pressure within the casing pipe 11 is provided inside the case. Further, an air feed port for feeding the compressed air is provided thereinside.
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