PURPOSE: To greatly save man-power and to promote construction efficiency by excavating a bedrock by an excavator body having an excavation device capable of enlarging and contracting, sucking excavated earth through an earth moving pipe at negative pressure to discharge earth to the ground, and spraying concrete to the wall of a hole from a nozzle 30.
CONSTITUTION: A revolution is made while rotating a drill 11 of an excavator body 10 to start excavation, and excavated earth is sucked through a suction port 21 of an earth moving pipe 20 and is discharge to the ground. After that, operation of pumps 33 and 34 is started and, at the same time, concrete is sprayed to a bedrock while rotating and oscillating a nozzle, and a lining layer 40 is formed. Then, in the case excavation is made up to specific depth, a diameter of a guide plate 14 is contracted, and after a diameter of a bit 11C of the drill 11 is contracted, the excavator body 10 is withdrawn. An uncompleted scope of the lining layer 40 is such that the nozzle 30 is provided to the lower part of the earth moving pipe 20 separated from the excavator body 10 and that concrete is mechanically sprayed by the nozzle 30 while lowering the earth moving pipe 20 to correspond thereto. According to the constitution, excavation, earth-moving and earth retaining work can be executed by one con struction device.
NAITO TEIJI
ARAI MASAO
ARIYAMA MOTOSHIGE
OYA HIROSHI
