STARTING METHOD OF SHIELD EXCAVATOR IN DOUBLE SECTION SHIELD METHOD

摘要

PURPOSE:To prevent water leakage specially in an entrance in the case of starting in a double section shield method by which a plurality of shield excavators are connected to drive forward to assemble an independent tunnel lining every shield excavator backward of them. CONSTITUTION:A first step packing 21 and a second step packing 22 are mounted front and rear of the circumferential surface of an entrance 1 over the whole circumference. According to the driving of a connection body 3 between two shield excavators 2, when a skin-plate 8 reaches the first step packing 21 through the second step packing 22, and a cover body 23 covering gaps 25c and 11 formed between the entrance 1 and built-up rings 5 and between the rings 5 is mounted to the rear end of the entrance 1. The gap 11 between the rings 5 which can not be covered with the packings 21 and 22 is covered with the covering body to stop water.