Title : Seismic earth pressure computation using modified dubrova’s model

Page : PP.53-64

Author(s) : Amol Maskar and Suhasini Madhekar

Keyword : Seismic active earth pressure, modified Dubrova’s model, pseudo-static methods, pseudo-dynamic methods, nonlinear distribution, redistribution principle

Abstract : 

The design of a retaining wall needs complete knowledge of the earth pressure behind it for both active and passive conditions. In case of earthquake events, the design requires special attention to reduce the devastating effects. Under seismic condition, the available literature mostly focuses on pseudo-static and pseudo-dynamic methods, to evaluate the seismic earth pressure. However, these methods do not incorporate the effect of wall movement on the earth pressure distribution. Dubrova was the first to consider such effect. In this paper, modified Dubrova’s model based on redistribution principle (considering seismic effect) has been developed. The model is used to determine the nonlinear distribution of active earth pressure acting on a retaining wall, by considering various modes of wall movement. For checking the accuracy and applicability of the predictions using the modified Dubrova’s model, equations of active earth pressure are compared to the available experimental results for retaining walls, considering variation in height, soil friction angle, wall friction angle, and seismic acceleration coefficient. The modified Dubrova’s model considers both nonlinear static and nonlinear seismic earth pressure distributions. Parametric studies are performed to study the distribution of seismic earth pressure along the height of a retaining wall. It is found that the maximum earth pressure occurs between 0.35 H to 0.40 H above the wall base (H is the height of the mat). Results obtained using modified Dubrova’s model are in good agreement with experimental results of Tsagareli and others. Present study gives 25% higher earth pressure compared to Tsagareli’s method, whereas 30% higher earth pressure compared to Ghazavi and Yeganeh’s method. Though seismic earth pressure obtained by all above approaches and that obtained by modified Dubrova’s model has different formulation background, the final earth pressure distribution is approximately of the same nonlinear nature.

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