| 摘要 |
A measuring technique for producing a three-dimensional image and information relating to the type of sand, clay or gravel which defines a wall or walls of a deep concealed underground excavation which is filled with a stabilizing liquid, and which technique facilitates accurate and safe construction, utilizes a transducer which irradiates a surface of the excavation with ultrasonic waves and detects the waves which are reflected back thereto. The transducer scans horizontally in incremental stages which occur with a predetermined angle pitch. After each scan is completed, the transducer is vertically displaced by a predetermined amount and the horizontal scan is repeated. The time required for a wave to reach and be reflected back to the transducer is used to determine the distance of the wall from the device. This is used in combination with data indicative of the horizontal and vertical positions of the device to enable the shape of the surface to be determined and for qualitative data such as the type of material from which the wall is composed, to be determined from the patterns produced by the received waves.
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