A performance-based approach for design of ground densification to mitigate liquefaction

In performance-based geotechnical earthquake engineering, the required degree and spatial extent of ground densification for mitigation of liquefaction beneath a structure should be determined based on the acceptable levels of performance of foundation. Currently, there is no solution for evaluation of the amount of settlement and tilt of footings constructed on a densified ground which is surrounded by a liquefiable soil. This implies the need for numerical procedures for simulation of seismic behavior of shallow foundations supported on both liquefiable and densified subsoil. In this paper, the dynamic response of shallow foundations on a densified ground is studied using a 3D fully coupled dynamic analysis. For verification of the numerical model, simulation of a series of centrifuge experiments has been carried out and the results were compared with the experimental measurements. After verification of the numerical model, a comprehensive parametric study has been performed to develop a methodology for estimating the effectiveness of subsoil densification in reducing liquefaction-induced settlement of shallow foundations. Range of problem variables were considered in a way that the possibility of bearing capacity failure is low enough. The proposed methodology can be utilized for development of a performance-based design procedure for liquefaction hazard mitigation by soil densification.

[1]  Jonathan D. Bray,et al.  Mechanisms of Seismically Induced Settlement of Buildings with Shallow Foundations on Liquefiable Soil , 2010 .

[2]  Andrew Brennan,et al.  Influence of bearing pressure on liquefaction-induced settlement of shallow foundations , 2013 .

[3]  Stuart K. Haigh,et al.  Post-earthquake behaviour of footings employing densification to mitigate liquefaction , 2007 .

[4]  Boris Jeremić,et al.  Evaluation of variation of permeability in liquefiable soil under earthquake loading , 2012 .

[5]  C. Juang,et al.  US–Taiwan workshop on soil liquefaction: overview and research needs , 2004 .

[6]  Numerical analysis of liquefaction-induced bearing capacity degradation of shallow foundations on a two-layered soil profile , 2013 .

[7]  Hadi Shahir,et al.  Estimating liquefaction-induced settlement of shallow foundations by numerical approach , 2010 .

[8]  Hadi Shahir,et al.  Employing a variable permeability model in numerical simulation of saturated sand behavior under earthquake loading , 2014 .

[9]  Xiangwu Zeng,et al.  Bearing capacity failure of shallow foundations in earthquakes , 1998 .

[10]  Mahdi Taiebat,et al.  Study of pore pressure variation during liquefaction using two constitutive models for sand , 2007 .

[11]  M. Pastor,et al.  Static and dynamic behaviour of soils : a rational approach to quantitative solutions. I. Fully saturated problems , 1990, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[12]  Ricardo Dobry,et al.  SEISMIC RESPONSE OF SHALLOW FOUNDATION ON LIQUEFIABLE SAND , 1997 .

[13]  I. M. Idriss,et al.  SIMPLIFIED PROCEDURE FOR EVALUATING SOIL LIQUEFACTION POTENTIAL , 1971 .

[14]  Majid T. Manzari,et al.  SIMPLE PLASTICITY SAND MODEL ACCOUNTING FOR FABRIC CHANGE EFFECTS , 2004 .

[15]  Kohji Tokimatsu,et al.  Settlement of Buildings on Saturated Sand During Earthquakes , 1977 .

[16]  Kenji Ishihara,et al.  LIQUEFACTION CHARACTERISTICS OF SAND DEPOSITS AT AN OIL TANK SITE DURING THE 1978 MIYAGIKEN-OKI EARTHQUAKE , 1980 .

[17]  George D. Bouckovalas,et al.  Insight into the Seismic Liquefaction Performance of Shallow Foundations , 2013 .

[18]  A. Elgamal,et al.  Computational modeling of cyclic mobility and post-liquefaction site response , 2002 .

[19]  Takashi Watanabe,et al.  DAMAGE TO OIL REFINERY PLANTS AND A BUILDING ON COMPACTED GROUND BY THE NIIGATA EARTHQUAKE AND THEIR RESTORATION , 1966 .