DYNAMIC COMPACTION STUDY OF ELIMINATING THE COLLAPSIBILITY OF EOLIAN DEPOSIT FINE SAND

The eolian deposit fine sand in desert area has slight to severe collapsibility. Eliminating the collapsibility for the foundation soil of eolian deposit fine sand is a problem to be solved urgently in engineering. Combined with the engineering example, the dynamic compaction method is used to reinforce the foundation soil of eolian deposit fine sand. The effect and law of the dynamic compaction method to eliminate the collapsibility of the eolian deposit fine sand are evaluated with shallow plate loading test and laboratory soil test. The results show that the collapsibility of the eolian deposit fine sand is mainly affected by the moisture content and the density. The water content is especially prominent for the collapsible deformation. Before the dynamic compaction, the water content of the soil should be sufficient to make the soil moisture content reach the optimal water content. In the dynamic consolidation and reinforcement, the optimum hammer number in the filled site is 10 strike, and the optimum hammer number in the excavated site is 8 strike. The dynamic design of information construction(ie., the observational method) has to be used. After dynamic compaction, the bearing capacity of the eolian deposit fine sand is two times more than that before the dynamic compaction. In the collapsible test, the deformation increment of the eolian deposit fine sand is less with the time. The dynamic compaction method improves the collapsibility of the aeolian fine sand, among which the water is the main factor of controlling the collapsibility, and the dynamic compaction is the secondary factor. The research results help to provide reference for the design and construction of the foundation soil of eolian deposit fine sand by dynamic compaction, and provide reference for similar foundation treatment.