Improving the Design and Performance of Cuts and Retaining Structures in the Piedmont
Physiographic Province
Project Description
A large portion of the United States Infrastructure is underlain by residual soils. The
Interstate 85 corridor in the Eastern United States generally follows the southern Piedmont, a
physiographic province consisting of residual soils. A great deal of transportation infrastructure
exists in this zone which will be refurbished, upgraded, and renovated as the global economy
recovers. Cuts, slopes, and retaining structures are necessary to provide grade changes where
real estate boundaries and geometric limitations exist. Design of these cuts using traditional soil
mechanics theories is almost always conservative and wasteful. Current data demonstrates the
influence of suction on excavations in residual soils results in significant measureable impacts
that may be integrated into design infrastructure in these soils. In either case, widespread
application of these findings hinges on the ability to measure soil strength properties reliably,
using laboratory and field methods, and maintain or monitor suction during and after
construction. Updating analysis and design methods for these structures to reflect the actual
behavior of residual soils will result in significant cost savings and construction efficiencies
while maintaining safety. In other words, retaining structures and cuts can be delivered in a
manner that is more cost effective, safe, and thus sustainable.
Research conducted by the PI and others over the past decade demonstrates the impacts
of factors such as residual soil fabrics and unsaturated soil behavior on the performance of
excavations and slopes in residual soils. The objective of this study is to integrate these
behaviors into design and performance predictions through a program of enhanced soil testing
and instrumentation of facilities at full scale. The scope of work includes instrumenting and
monitoring sacrificial walls and cuts at a well characterized research site along with similar
infrastructure constructed by ALDOT, NCDOT, or other research partners. The expected
deliverable of this project is an engineering ready application guide for cuts, slopes, and retaining
structures constructed in residual soils.
Qualifications of Researcher
Dr. Anderson and his research team are well positioned to conduct this study. The group
has developed effective techniques for measuring strength and suction properties of residual
soils. In a research project for the North Carolina Department of Transportation, it was shown
that the theoretical earth pressure was never mobilized, and consideration of the impacts of
residual soil fabrics on the estimation of earth pressures was essential for rational design. This
study was extended by and investment from the Federal Highway Administration through an
Eisenhower Fellowship to study the stability of cuts and slopes in residual soils with a focus on
the impact of soil suction. In general, the team has extensive experience with instrumentation of
all types of construction projects.
Central to delivery of this project is the National Geotechnical Experimentation Site at
Auburn University, an internationally recognized residual soil research site. Beginning with the
establishment of the site in 199X, Auburn, Georgia Tech, the University of Florida, ALDOT, and
many others have performed extensive insitu and laboratory tests on the residual soils at the site.
The Aubun NGES exists as a reservation established specifically for the construction and testing
of geotechnical facilities.
Budget
Personnel Salaries:
Anderson, J. Brian
GRA 1 (50%)
Total Personnel
Employee Benefits:
Fringe Benefits A (27.5% Full-Time)
Fringe Benefits B (2.6% Graduate Students)
Total Fringe Benefits
(By J. Brian Anderson on 10/02/2011)
FY'12: 04/01/12 to 09/30/12
FY'13: 10/01/12 to 09/30/13
Months
Cost
Months
Cost
0.50
$
4,949.72
0.50
$
4,949.72
6.00
$
9,000.00
12.00
$
18,000.00
$
13,949.72
$
22,949.72
Rate
27.50%
2.60%
$
$
$
1,361.17
234.00
1,595.17
Consumable Supplies & Travel:
Sensors, cabling, laboratory supplies
Travel
Total Consumable Supplies & Travel
$
$
$
4,543.07
500.00
5,043.07
Non-expendable Equipment:
None
Total Equipment
$
$
TOTAL DIRECT COST
INDIRECT COST (No equipment)
TOTAL COST
$
Rate
47.5%
Rate
27.50%
2.60%
-
$
9,779.28
$
30,367.24
$
$
$
1,361.17
468.00
1,829.17
$
$
$
2,722.35
702.00
3,424.35
$
$
$
1,000.00
1,000.00
2,000.00
$
$
$
5,543.07
1,500.00
7,043.07
$
$
20,587.96
Rate
48.0%
Prj. Total
Cost
$
9,899.44
$
27,000.00
$
36,899.44
-
$
$
-
$
26,778.89
$
47,366.85
$
12,853.87
$
22,633.15
$
39,632.76
$
70,000.00
$
$
Rate
9,899.44
1,500.00