LTRC technical summary report, 423

Louisiana Transportation Research Center

United States. Federal Highway Administration

FHWA/LA.07/423

Tech Report

Louisiana

657388914

Technical summary report; Nov. 2008.

Louisiana Transportation Research Center

NTL-HIGHWAY/ROAD TRANSPORTATION-Soils and Geology

The presence of a weak soil supporting structural foundations results in low load bearing capacity and

excessive settlements, which can cause structural damage, reduction in durability, and/or deterioration in

performance level. Conventional treatment methods replace part of the weak cohesive soil with an

adequately thick layer of stronger granular fill, increase the dimensions of the footing, or combine both

methods. However, an alternative and more economical solution uses geosynthetics to reinforce soils, which

can be done by either reinforcing cohesive soil directly or replacing poor soils with stronger granular fill in

combination with the inclusion of geosynthetics. The resulting composite zone (reinforced soil mass) will

improve the load carrying capacity of the footing and provide better pressure distribution on top of

underlying weak soils, reducing associated settlements.

Benefits of including reinforcements within soil mass to increase the bearing capacity and reduce the

settlement of soil foundation have been widely recognized. Many hypotheses have been postulated about the

failure mode of reinforced soil foundation (RSF). However, the failure mechanism of reinforcement is still

not fully understood in RSF as compared to other reinforced soil applications. Therefore, it is important to

investigate the reinforcement mechanism of reinforcing soils for foundation applications.

PDF

04-2GT

US Transportation Collection