Underground diaphragm wall groove wall three-dimensional shape detection system and method

The invention discloses an underground diaphragm wall slot wall three-dimensional shape detection system and method.The detection system comprises slot wall coordinate detection equipment which is preset at the top of a to-be-detected slot wall to collect position coordinates and can be lowered to the bottom of the slot wall through a winch system to open a plurality of supporting arms and then lifted to the top of the slot wall; in the lifting process, data collection is conducted once every other preset distance; the groove wall space coordinate calculation module is used for calculating space coordinates of contact points of the support arms and the groove wall at different depths according to the position coordinates and the collected data; the point cloud splicing module is used for eliminating data abnormal points and splicing point clouds into a curved surface to obtain an actual slot wall three-dimensional form, and generating a theoretical slot wall three-dimensional form; and the model difference an