Municipal pipeline foundation pit well point dewatering excavation supporting device

The invention provides a municipal pipeline foundation pit well point dewatering excavation supporting device, and belongs to the technical field of municipal pipeline construction. The supporting device comprises a fixed frame, a sliding frame, a mounting frame, a water retaining assembly, an extrusion fixing assembly and a protection assembly, wherein the water retaining assembly, the extrusion fixing assembly and the protection assembly are arranged on the fixed frame; a sliding frame is slidably arranged at the top end of the fixed frame; a mounting frame is movably arranged at the top end of the sliding frame; water retaining assemblies are arranged on the side walls of the periphery of the mounting frame correspondingly and used for shielding a foundation pit excavation point so as to block upward gushing muddy water. An extrusion fixing assembly is arranged above the mounting frame and is used for fixing external well digging equipment; a protection assembly is arranged at the top end of the mounting f