Anchorage structure suitable for excavation-free foundation pit of moderately weathered rock stratum and construction method

The invention discloses an anchorage structure suitable for an excavation-free foundation pit of a moderately-weathered rock stratum and a construction method. Round secant piles are arranged as pile foundations, rectangular secant piles and the round secant piles are in lap joint to form a shaft type underground diaphragm wall, the underground diaphragm wall is embedded into moderately-weathered rock, a plurality of rectangular secant piles in the bridge direction and the round secant piles are in lap joint to form an underground diaphragm wall in the bridge direction, and the underground diaphragm wall is embedded into the moderately-weathered rock stratum. A plurality of transverse-bridge-direction rectangular secant piles are rigidly connected to form a transverse-bridge-direction type underground diaphragm wall, the longitudinal-bridge-direction underground diaphragm wall and the transverse-bridge-direction type underground diaphragm wall are staggered to form cells, the cells and the front end area of a