Abstract: The undergrand pool is deep foundation pit in the sewage treatment station and heat exchange station in new developed area of Handan Steel Iron Co.Ltd,the excavation is 13.7 m and 13.5 m deep respectivly.the excavation has rich groundwater and with claypan at upper part and sand gravel stratum at lower part.According to the real engineering situation,the combined supporting technology is adoped with soil nailing wall at upper part and retaining piles at lower part,the technology makes full use of the soil nailing wall support at upper shallow position and retaining piles at lower deep position,the technology is safe,reliable,economical and practical.It is worth popularizing in deep excavations.