Abstract: Dynamic replacement,as a treatment method for soft soil foundation,has some shortcomings such as the gap between the replacement columns and the basement,large post-construction settlement,and low construction efficiency. In view of this,a dynamic replacement method with prebored filling is proposed to enhance the bearing capacity of foundation and reduce the post-construction settlement by tamping the prebored columns filled with materials under high energy level. The method is verified feasible through plate loading test,heavy dynamic penetration test and water filling and preloading test after tamping,and finally successfully applied to the whole soft soil foundation site. The number of dynamic sounding blows after tamping increased by over 260%,the bearing capacity of composite foundation reached 280 kPa,and the maximum settlement of tank foundation and the settlement difference of adjacent measuring points are far less than the requirements of specification. The successful application of this method serves as reference for the treatment of similar foundation.

Key words: soft soil foundation, dynamic replacement method, dynamic compaction with high energy level, prebored, water filling and preloading test, post construction settlement