CUTTING EDGE PART BOUNDARY IDENTIFICATION DEVICE AND CAISSON IMMERSION METHOD

To provide a cutting edge part boundary identification device for identifying a boundary between a region exposed to a workroom and a region intruded into the ground on an inner peripheral surface of a cutting edge part and a caisson immersion method using the device.SOLUTION: A cutting edge part boundary identification device 100 includes: an illumination unit 10 for illuminating the inside of a workroom R of a pneumatic caisson 1; an imaging unit 20 for imaging a film F of the inside the workroom R; and a film analysis unit 32 for the film F. The imaging unit 20 detects an intensity distribution of light in a predetermined wavelength band for each pixel of the film F. On the basis of the intensity distribution detected by the imaging unit 20, the film analysis unit 32 identifies a boundary W between an exposure region, of an inner peripheral surface 4a of a cutting edge part 4, exposed to the workroom R and an intrusion region, of the inner peripheral surface 4a, intruded into the ground G. A caisson immersion method includes installation by immersing the pneumatic caisson 1 to a predetermined depth from the ground surface side of the ground G while adjusting an amount of the cutting edge part 4 excavating a lower ground G2 using a result of identifying the boundary W of the cutting edge part boundary identification device 100.SELECTED DRAWING: Figure 1 【課題】刃口部の内周面における作業室への露出領域と地盤への貫入領域との境界を特定する刃口部境界特定装置及びこれを利用したケーソン沈設方法を提供する。【解決手段】刃口部境界特定装置１００は、ニューマチックケーソン１の作業室Ｒ内を照明する照明部１０と、作業室Ｒ内の画像Ｆを撮像する撮像部２０と、画像Ｆの画像解析部３２とを含む。撮像部２０は、画像Ｆの画素毎に所定の波長帯域における光の強度分布を検出する。画像解析部３２は、撮像部２０により検出された前記強度分布に基づいて、刃口部４の内周面４ａのうちの作業室Ｒに露出する露出領域と内周面４ａのうちの地盤Ｇ内に貫入している貫入領域との境界Ｗを特定する。ケーソン沈設方法は、刃口部境界特定装置１００の境界Ｗの特定結果を利用して刃口部４の下方地盤Ｇ２の掘削量を調整しつつ、ニューマチックケーソン１を地盤Ｇの地表面側から所定深さまで沈下させて設置する。【選択図】図１