Foundation pit protection structure for building

The invention relates to the technical field of foundation pit protection, in particular to a foundation pit protection structure for a building. The protective device comprises a protective frame and a pair of telescopic assemblies installed on the side face of the protective frame. The stability of the whole device is maintained through static friction force generated by the supporting rods at the bottom end and the bottom end of the foundation pit, the supporting rods are of a right-angle structure and can be completely attached to the two sides of the corner of the foundation pit to conduct attached protection on the two sides of the foundation pit, and meanwhile the hydraulic rods stretch out and draw back vertically to drive the supporting rods at the top end to move vertically along the corner of the foundation pit. The top of the supporting rod located at the top end is flush with the top end of the foundation pit so as to adapt to protection of foundation pits with different heights; a triangular str