The Hole and Groove Sediment Thickness Detector adopts the probe pressure-tilt angle method to detect the thickness of sediment. Working principle: when the sediment probe is lowered to the bottom of the hole or groove, the instrument will read the probe state; when the probe tilt exceeds a certain range, the probe will be is adjusted until it is upright, and the instrument will have the probe extend out slowly; meanwhile, the probe pressure, tilt angle and extension length are measured; when the probe reaches the bedrock at the bottom of the hole, the pressure and tilt angle of the probe will increase abruptly, and the extension length of the probe will be the thickness of sediment at the current position.