Publication Abstract

Proceedings of the Deep Mixing 2015 Conference, (DFI)

Vertical Load Sharing of Piled Raft with Grid-Form Deep Mixing Walls
K. Yamashita, Takenaka Corporation, Japan; T. Tanikawa, Takenaka Corporation, Japan; Y. Shigeno, Takenaka Corporation, Japan; J. Hamada, Takenaka Corporation, Japan

This paper offers a case history of piled raft foundation in soft ground supporting a twelve-story building in Tokyo. To increase bearing capacity of the soft soil as well as a countermeasure of liquefaction, grid-form deep cement mixing walls (DMWs) were employed with the piled raft. Based on the long-term monitoring results, the ratio of the load carried by the DMWs to the effective structure load after the construction of the raft was estimated to be 0.3 while that carried by the piles was 0.7. In order to clarify the contribution of the DMWs to bearing the structure load, numerical simulation of the settlement and the load sharing among the piles, the DMWs and the unstabilized soil was performed using a three-dimensional finite element model. The results of the numerical simulation agreed well with the measured values, when the Young’s modulus of the DMWs obtained from the unconfined compressive tests was adopted and the shear modulus of the soft soil was reduced to 50% of that at small strains.

 article #2065; publication #1013 (DM-2015)