STABILITY OF WATERFRONT RETAINING WALL SUBJECTED TO PSEUDO-DYNAMIC EARTHQUAKE FORCES AND TSUNAMI

The paper pertains to a study in which the waterfront retaining wall has been analyzed for its stability when it is exposed to the forces jointly coming from an earthquake and tsunami. Closed form solutions following the simple limit equilibrium principles have been proposed. For the calculation of the seismic passive earth pressure and the wall inertia force, pseudo-dynamic approach has been considered, while the hydrodynamic and the tsunami wave pressures have been calculated using different approximating solutions available in literature. The results presented in the sliding and overturning modes of failure of the wall show that the stability of the wall gets seriously challenged when it gets jointly exposed to the effects of the tsunami and earthquake. About 92% decrease is observed in the value of the factor of safety in sliding mode of failure of the wall as the ratio of tsunami wave height to the upstream still water height increases from 0 to 1.5. Also, the critical mode of failure of the wall has been found to be that of the overturning. Effect of different parameters involved in the analysis has also been studied and it has been observed that quite a few of them like kh, kv, ϕ, δ, ru have a significant effect on the stability of the wall. Comparison with a previously existing methodology using pseudo-static approach suggests that the present pseudo-dynamic approach is more realistic and comparatively less conservative and hence can be used as a handy simple economic method for the design of the waterfront retaining walls exposed to the combined effects of earthquake and tsunami.

[1]  Syed Mohd Ahmad,et al.  Design of waterfront retaining wall for the passive case under earthquake and tsunami , 2007 .

[2]  Deepankar Choudhury,et al.  Dynamic active earth pressure on retaining structures , 2006 .

[3]  Deepankar Choudhury,et al.  Seismic passive resistance by pseudo-dynamic method , 2005 .

[4]  Deepankar Choudhury,et al.  Pseudo-dynamic approach of seismic active earth pressure behind retaining wall , 2006 .

[5]  Harry Yeh,et al.  Maximum fluid forces in the tsunami runup zone , 2006 .

[6]  Robert M. Ebeling,et al.  The Seismic Design of Waterfront Retaining Structures , 1992 .

[7]  Braja M. Das,et al.  Principles of Soil Dynamics , 1992 .

[8]  Takahiro Sugano,et al.  SEISMIC DESIGN OF PORT STRUCTURES , 2004 .

[9]  Syed Mohd Ahmad,et al.  Pseudo-dynamic approach of seismic design for waterfront reinforced soil-wall , 2008 .

[10]  Xiangwu Zeng,et al.  The Seismic Response of Waterfront Retaining Walls , 1990 .

[11]  Rowland Richards,et al.  Seismic Behavior of Gravity Retaining Walls , 1979 .

[12]  H. Westergaard.  Water Pressures on Dams During Earthquakes , 1933 .

[13]  Gerald Müller,et al.  An investigation of breaking wave pressures on inclined walls , 1993 .

[14]  Ioannis Anastasopoulos,et al.  Seismic behaviour of flexible retaining systems subjected to short-duration moderately strong excitation , 2004 .

[15]  S. Kramer.  Geotechnical Earthquake Engineering , 1996 .

[16]  Syed Mohd Ahmad,et al.  Stability of waterfront retaining wall subjected to pseudo-static earthquake forces , 2007 .

[17]  Deepankar Choudhury,et al.  Seismic rotational displacement of gravity walls by pseudo-dynamic method: Passive case , 2007 .

[18]  Deepankar Choudhury,et al.  Effects of body waves and soil amplification on seismic earth pressures , 2008 .

[19]  M. S. Kirkgöz,et al.  Breaking wave impact on vertical and sloping coastal structures , 1995 .

[20]  Syed Mohd Ahmad,et al.  Stability of Waterfront Retaining Wall Subjected to Pseudodynamic Earthquake Forces , 2008 .