During earthquake ground shaking earth pressures on retaining structures can cyclically increase and decrease as a result of inertial forces applied to the walls and kinematic interactions between the stiff wall elements and surrounding soil. The application, based on limit equilibrium analysis, of a pseudostatic inertial force to a soil wedge behind the wall [the mechanism behind the widely-used Mononobe- Okabe (M-O) method] is a poor analogy for either inertial or kinematic wall-soil interaction. This paper demonstrates that the kinematic component of interaction varies strongly with the ratio of wavelength to wall height (λ/H), asymptotically approaching zero for large λ/H, and oscillating between the peak value and zero for λ/H < 2.3. Base compliance, represented in the form of translational and rotational stiffness, reduces seismic earth pressure by permitting the walls to conform more closely to the free-field soil displacement profile. This framework can explain both relatively low seismic pressures relative to M-O predictions observed in recent experiments with λ/H > ~10, and relatively high seismic earth pressures relative to M-O from numerical analyses in the literature with λ/H = 4.
|Number of pages||10|
|Journal||Journal of Geotechnical and Geoenvironmental Engineering|
|Early online date||16 Mar 2015|
|Publication status||Published - 1 Jul 2015|
- Dynamic testing
- Seismic earth pressure