Being leakage position detection manner of the waterproof sheet which put the Textile Div. for additional strength and

摘要

PROBLEM TO BE SOLVED: To check surely the position of water leakage of a sealing sheet by a method wherein a pulse is generated in one of adjacent sensor materials and the position of the water leakage is detected from a response waveform coming back to the other sensor material. SOLUTION: When a sealing sheet 4 is impaired, percolating water collected in a disposal plant passes through a place 6 of impairment, permeates into an inside fibrous part and soon spreads to a line 7 formed of two adjacent sensor materials 3a and 3b and this is detected by a leakage current detector. In order to specify the line, subsequently, each set of the adjacent sensor materials 3a and 3b is checked up sequentially as to whether an electric current can pass through or not, by the leakage current detector, and thereby the line 7 at which the water leaks is specified. An oscilloscope 9 being connected to the specified line 7, a pulse is generated in one sensor material 3a and the place of water leakage is detected from a response waveform 10 coming back to the other sensor material 3b. Since a large waveform is obtained from the place 6 of water leakage, this place can be indexed in an order of several centimeters on the oscilloscope.