Large deep foundation pit inner supporting system with safety system

The invention discloses a large-scale deep foundation pit inner supporting system with a safety system, and belongs to the technical field of deep foundation pit inner supporting systems, the large-scale deep foundation pit inner supporting system comprises a supporting pile vertically arranged on the edge of a foundation pit, and a three-dimensional supporting frame is arranged on the supporting pile and comprises a plurality of rectangular unit sections; at least one side part of the three-dimensional supporting frame is formed by arranging a plurality of rectangular unit sections, the rectangular unit sections are connected with rotary connecting pieces, the rotary connecting pieces are fixedly connected with inner supporting bodies and outer supporting bodies which are arranged in an L shape, and the inner supporting bodies and the outer supporting bodies are located on the two sides of the rectangular unit sections respectively; first locking pieces and second locking pieces are arranged on the inner sup