| 摘要 |
<p>Monitor apparatus for a bed underlying water comprises at least one sensor for being in alarm signal relationship with said bed, such that sufficient flow of water will enable at least one said sensor to provide at least one alarm signal in response to corresponding errosion of the bed, at least one said sensor being adapted to be in a disabled mode during normal flow conditions; and circuitry for said at least one sensor. A downward array of sensors may be buried in the bed during normal flow conditions so as to be in a disabled mode. The sensor may comprise an oscillatable arm (21) having a first end portion (22) for supporting the arm, and a second end portion (23) comprising a sensor cell (25) e.g. an omni-directional mercury switch. The alarm signal may be indicative of risk of collapse of a hydraulic structure, e.g. the foundation of a bridge pier. <IMAGE></p> |
