Grab bucket for underground diaphragm wall trenching machine

The utility model discloses a grab bucket for an underground diaphragm wall trenching machine. The grab bucket mechanism comprises two grab buckets which are symmetrically arranged and a grab bucket driving mechanism, the grab bucket driving mechanism is in driving connection with the tops of the two grab buckets; reinforcing bucket teeth used for increasing the digging depth and width of the grabbucket are arranged at the bottoms of the two grab buckets. The side wall of at least one grab bucket is provided with a pipeline protection device for excavating a soil body at the bottom of a pipeline; by arranging the pipeline protection device, the excavation section can go deep into the position under the pipeline in the horizontal direction by controlling the grab bucket to move, soil underthe pipeline is pushed out from the side face, the soil under the pipeline is rapidly removed under the condition that the safety of the pipeline is guaranteed, and the grooving construction task ofthe underground diaphragm w