Dissertation/Thesis Abstract

Numerical Modeling of Gravity Wall and Cantilever Wall under Seismic Activities with Different Backfill Cohesions
by Khan, Faiza, M.S.Ed., Southern Illinois University at Edwardsville, 2019, 59; 27666214
Abstract (Summary)

Man-made structures over the time have been prone to failures due to natural calamities and disasters causing huge amounts of life and material losses. One of the most common disasters that strike are earthquakes damaging the infrastructures with a different and unpredictable pattern each time. To understand the mechanism of failure and its effect numerical study on cantilever wall for different earthquakes was done by (Osouli & Zamiran, 2017). The aim of the study was focused on the cohesion of the backfill material and its effect on the failure of wall. Upon literature review the need to expand it beyond cantilever wall was realized. Cantilever wall and gravity wall are different in terms of shape, purpose and mechanism, but are they different in terms of failures and how does the backfill cohesion come in role was the question. The primary focus of the study is to model performance of a gravity wall backfilled with materials that have various cohesions under three different earthquake loading inputs. Verification of the work was a step by step process of a literature review followed by understanding the input codes used by (Osouli & Zamiran, 2017) in their study. The input earthquake velocities used in the study were checked for any corrections in (Seismosoft, 2016) software. The codes were then individually input in FLAC 2D software from (Itasca, 2011)and numerical analyses was performed, the output of the analyses was then extracted, and figures were generated in Microsoft excel to compare them with the original results. . The backfill cohesions are varied from 0 kPa to 30 kPa to understand the effect of their variation on the wall performance. Loma Prieta, Kobe and Chi-Chi earthquakes inputs are used for the dynamic analysis. The wall is modeled using the finite difference method. The monitored performance of the wall included seismic earth pressures, peak ground accelerations, relative wall displacement, total and incremental seismic earth thrust and point of action on the wall. The results are compared to that of the cantilever wall with same backfill cohesions. Both the gravity and cantilever walls are 6 meters high. The relation between total and incremental seismic earth thrust coefficients and backfill cohesions is closely monitored. The results indicated that in general as the backfill cohesion increased from 0 to 30 kPa the total seismic earth thrust coefficient decreased for the stem section of the wall however as the cohesion increased the results also increased for the heel section of the wall. The incremental seismic earth thrust of the wall decreased with the increase in backfill cohesion of the wall for both stem and heel.

Indexing (document details)
Advisor: Osouli, Abdolreza
Commitee: Fries, Ryan, Benjankar, Rohan
School: Southern Illinois University at Edwardsville
Department: Civil Engineering
School Location: United States -- Illinois
Source: MAI 81/7(E), Masters Abstracts International
Subjects: Geotechnology, Civil engineering
Keywords: Cantilever wall, FDA, FLAC 2D, Gravity wall, Numerical modelling
Publication Number: 27666214
ISBN: 9781392469095
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