NUMERICAL ANALYSIS OF BEHAVIOR OF T-SHAPED CEMENT-SOIL DEEP MIXING PILE COMPOSITE FOUNDATION UNDER EMBANKMENT LOADS

With a review of disadvantages of traditional deep mixing cement-soil pile techniques,a new type of cement-soil deep mixing technique named T-shaped cement-soil deep mixing pile is introduced.Three-dimensional numerical simulation is taken to analyze the behavior of T-shaped cement-soil deep mixing pile composite foundation under embankment loads comparing with ordinary shaped cement-soil deep mixing pile based on filed tests.The results indicate that when other parameters keep the same,because of the effect of enlarged cap of T-shaped cement-soil deep mixing pile,load sharing ratio of T-shaped cement-soil deep mixing pile is higher than ordinary shaped cement-soil deep mixing pile,but the negative skin friction of T-shaped pile is less than of ordinary pile in the upper reinforced area;additional stress in the upper T-shaped cement-soil deep mixing pile composite foundation is less than that of ordinary cement-soil deep mixing pile composite foundation;comparing to ordinary cement-soil deep mixing pile composite foundation,T-shaped cement-soil deep mixing pile can not only decrease the surface settlement of composite foundation and the lateral displacement in embankment foot,but also can decrease the differential settlement of composite foundation surface efficiently,so there is no need for cushion or geosynthetic-reinforced layer set above the pile top.