Foundation pit support system leakage point detection method and detection device

The invention discloses a method and a device for detecting leakage points of a foundation pit support system, relates to the field of underground engineering leakage detection, and is used for solving the problem of low determination precision of leakage points of an underground diaphragm wall. The detection method comprises the steps that a dewatering well is formed in a foundation pit support, and a plurality of observation wells are formed in the exterior of the foundation pit support in multiple directions of the periphery of the foundation pit support; continuously dewatering in the dewatering well; tracer agents are sequentially put into the observation wells, and the horizontal direction of the foundation pit support leakage point is judged; and determining water flow directions of different depths in the observation well corresponding to the leakage point in the horizontal direction, and judging the depth position of the leakage point so as to obtain the accurate position of the leakage point of the