SEISMIC DISPLACEMENT PREDICTION OF RETAINING WALLS UPON DEEP EXCAVATIONS IN HANOI

Abstract

The high-rise buildings have been more and more built in large urbans in Vietnam, ofespecially Hanoi and Ho Chi Minh City. The basements of these buildings are popularly constructed by using retaining walls associated with the top-down method. Therefore, an estimation of the lateral displacement of the walls is extremely important in the construction process. This paper predicts the displacement of the diaphragm walls in deep excavations of Hk = 12m in Hanoi accounting for seismic loading. The walls are stably sustained using soil nail systems, struts, and top-down method. A finite element analysis software, PLAXIS 2D, is utilized to model the systems. Three soil models including Linear-Elastic, Morh-Coulomb, and Hardening Soil models are considered in the numerical analyses, while the elastic beam element is applied for the retaining walls. A seismic-effected ratio (Kc) is quantified in terms of the maximum lateral displacement induced by the earthquake to the maximum displacement due to the static load. The results show that the seismic-effected ratios are arranged from 1.4 to 1.28, 1.61 to 2.61, and 1.53 to 1.99 for Mohr-Coulomb, Hardening Soil, and Elastic soil models, respectively.