Pore-forming wall protection structure in karst stratum

The utility model discloses a pore-forming wall protection structure in a karst stratum. The pore-forming wall protection structure comprises a rock-socketed pile hole and an overburden layer pile hole, the rock-socketed pile hole and the overburden layer pile hole are coaxially arranged; a retaining wall structure is arranged in the overburden layer pile hole; the retaining wall structure is composed of an upper pile casing, a plurality of middle pile casings and a lower pile casing. Inserting parts are arranged at the upper parts of the middle pile casing and the lower pile casing; the lower portion of the middle protective cylinder and the lower portion of the upper protective cylinder are each provided with a groove part matched with the corresponding inserting part. The adjacent middle pile casings, the upper pile casing and the uppermost middle pile casing as well as the lowermost middle pile casing and the lower pile casing are in insertion connection through matching of the insertion parts and the gro