Abstract: The reinforcement of deep soft soil foundation is of great significance to the stability of dump slope. Based on the consolidation theory of sand well，the consolidation of deep soft foundation in a dump is studied. The consolidation degree of deep soft foundation under different time and different loading thickness is analyzed. The depth and spacing of vertical drainage system are determined，and the preloading time and layered height of deep soft foundation are optimized. The results show that the average consolida⁃ tion degree under surcharge preloading increases logarithmically with time，while the shear strength of the foundation increases exponentially with the increase of consolidation degree. The stability of the reinforced dump is analyzed by GeoStudio，and the safety factor of the dump is 1.190，which meets the safety requirements. The research results can provide technical support for the drainage consolidation treatment project of deep soft foundation in dump.

Key words: deep soft soil foundation, dump, degree of consolidation, drainage consolidation