Abstract:Through analyzing the data of the static loading tests(SLT) and the cone penetration tests(CPT),which are on the collapsible loess subgrade treated by dynamic compaction,the corresponding formulae of the characteristic value of dynamic subgrade bearing capacity fak and the minimum mean value of cone resistance qc are obtained. Accordingly,after method and standard of quantitative evaluation of dynamic subgrade bearing capacity are established on the basis of design requirement,and the dynamic subgrade bearing capacity is quantitatively evaluated using the CPT. Weak layers are found and areas with weak layers are determined in the dynamic subgrade. The collapsibility of dynamic subgrade is quantitatively appraised by the test method of soil samples from the investigation wells,and larger remnant collapses are found in 2 investigation wells in the dynamic subgrade. The cause of formation of weak layers is analyzed and lime piles are consdiered to eliminate the potential dangers in the areas with weak layers. Effective reinforcement depth and influencing depth after dynamic compaction are accurately decided using the CPT on the basis of subgrade bearing capacity standards,the effective reinforcement depth after dynamic compaction is also decided using soil test method on the basis of remnant collapse standards,and the difference of effective reinforcement depths between both methods is found.