The Behavior of Pore Water Pressure in Cohesive Subgrade Soils

This research focuses on the behavior of pore water pressure in subgrade cohesive soils under Falling Weight Deflectometer (FWD) tests. The deflection of a pavement structure largely depends on the deformation of subgrade soils, which is in turn dependent upon soil stiffness. Soil stiffness can be characterized by the resilient modulus. Experimental tests were performed for saturated and unsaturated soil specimens. Both saturated and unsaturated samples showed pore water pressure buildup and residual pore water pressure. As a result, the effective stress in specimen decreased and the stiffness of soil decreased as the number of loading cycles increased. Tensiometers were installed at U.S. 23 to observe the behavior of pore water pressure in flexible and rigid pavement, and then the Falling Weight Deflectometer (FWD) was used to simulate the effect of a moving wheel load. Increases in the pore water pressure occurred in both rigid and flexible pavement during FWD tests. Therefore, it can be concluded that the resilient modulus of a subgrade soil is reduced due to load induced increases in the pore water pressure. The pore water pressure buildup was affected by not only the surface pressure but also loading period. The different loading periods between the FWD and the single trailer truck at approximately 55 mph were observed, so the FWD does not precisely represent the conventional truck wheel load at U.S. 23 Delaware sites.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Civil Engineering

Grantor dc:publisher

The Ohio State University

Year dc:date

2003

Author dc:creator

• Lee, Jangguen

Contributors dc:contributor

• E. Wolfe, William

• Civil Engineering

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1364216774

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1364216774