doi:10.3850/key-Be-ISGI09

ABSTRACT

This paper presents the comparison of the behavior of stiffened deep cement mixing (SDCM) and deep cement mixing (DCM) piles by full scale tests as well as by under 5m high embankment loading. Subsequently, the results of the full scale field load tests were simulated by 3D finite element method (FEM) to back-analyze and confirm the design parameters which were used further in subsequent numerical experiments. The jet grouting method with a jet pressure of 22 MPa, was utilized in the installation of DCM piles. The SDCM pile consists of a precast reinforced concrete pile inserted at the center of DCM pile. The field test results showed that the settlements and lateral movements of the SDCM pile using prestressed concrete core with area ratio of 0.17 and length ratio of 0.85 was less than those of DCM pile by 40% and 60%, respectively. Moreover, the SDCM pile foundation increased the bearing capacity as much as 2.2 times. The average lateral pile capacity of SDCM piles was 15 times higher than the DCM piles. The strength reduction factor at the concrete core and DCM interface of 0.40 was obtained from full scale pullout test and was confirmed from the previous laboratory model tests. The length of the core pile influenced the settlements of the SDCM pile more than its cross-sectional area. However, both the length and cross-sectional area of core piles affected the lateral resistance of the SDCM pile.

© 2010 by Geotechnical Society of Singapore (GeoSS)