Based on geological investigation and ground penetrating radar were conducted to detect the secondary platform along the Guancheng section of the Dongguan embankment,which identified 77 anomaly points within the dam,with depths ranging from 0.5 to 5.5 m.Data processing and image interpretation helped pinpoint potential hazards,then the location and type of the hazard were determined.The formation mechanism of the settlement was comprehensively analyzed by combining the results of indoor and outdoor tests and the reinforcement scheme of high-pressure rotary jet pile is proposed.