Closing the Gaps in the Regulation of Municipal Solid Waste Landfills:
Defining the End of the Post-Closure Monitoring Period and the Stability of
Leachate Reticulation Landfills
M. A. Barlaz and M. A. Gabr
US Environmental Protection Agency
9/99 to 9/01
The objective of this research is to develop a plan to establish the scientific
basis for definition of the end of the post-closure monitoring period at municipal
solid waste (MSW) landfills. Landfills are projected to remain the dominant
alternative for MSW management. Current regulations specify termination
of the post-closure monitoring period 30 years after closure. While emissions
are likely to continue well beyond 30 years, regulatory agencies and landfill
owners lack the scientific basis to define an appropriate endpoint for post-closure
monitoring. In addition, the increased use of leachate recycle to enhance
MSW decomposition will result in changes in the properties of decomposed refuse,
increased methane emissions, more precise water management, enhanced settlement,
and a need to reconsider cover stability and design.
Accelerated Flushing of Subsurface PAHs: Phase I Demonstration at the
Former Lockbourne AFB Columbus, OH
M. A. Gabr
US Department of Energy/US Army Corps of Engineers through Informatics Corporation,
Richland, Washington
9/00 to 12/01
The former Lockbourne Air Force Base has been in operation since the early 1940s.
As a result of the site’s original mission, environmental subsurface contamination
was found within portions of the site during several Phase I & II Environmental
Site Assessments (conducted in the early 1990s.) The main objective of
this work is to implement the Well Injection Depth Extraction System (WIDE),
technology for in situ remediation of the target compounds at the RPA site utilizing
35 ft x 35 ft test area.
An Evaluation of the Application of Plasma Arc Vitrification to Improve the
Strength of Weak Soil and Weathered Rock
M. A. Gabr and P. Mayne (Georgia Institute of Technology)
NC Department of Transportation (NCDOT)
7/00 to 7/01
A portable plasma system will be utilized to create vitrified columns within
a failed slope comprised of residual plastic clay derived from underlying weathered
mudstone. The research program will be used to document the current geotechnical
properties of the clay and mudstone strata, as well as the resultant igneous
rock materials created after vitrification. Laboratory, field, and geophysical
testing techniques will be applied for characterization of the material properties
before and after the application of Plasma ArcVitrification as a ground modification
approach.
Cyclic Performance of Geogrid Reinforced Soil
M. A. Gabr
Tensar Earth Technologies, Inc.
9/00 to 12/00
The proposed scope of work includes characterization of the load-deformation
response of reinforced soil mass under stress controlled stress cycles simulating
18k single axle loading. Reinforcement grade, spacing, and location effect on
the stress magnitude and distribution at the reinforcement-subgrade interface
is investigated. Surface deformation profiles are correlated to fundamental
yielding mechanisms and correlated to the layered system strength and stiffness
properties.
Effective Anchoring Mechanisms of Propane Tanks
M. A. Gabr
Propane Foundation
1/00 to 12/00
The proposed scope of work includes characterization of the tractive forces,
identification of feasible anchoring systems, the performance of limited testing
program to quantify the soil-anchors interface strength properties, and development
of innovative anchoring system to minimize damage during flooding and hurricane
conditions.
P-Y Curves for Laterally Loaded Drilled Shafts Embedded in Residual Soft Weathered
Rock
M. A. Gabr and R. H. Borden
NC Department of Transportation/Federal Highway Administration
7/99 to 7/01
The objective of this research is to develop and validate a procedure for design
and analysis of laterally loaded drilled shafts embedded in the Piedmont weathered
rock profiles. The proposed procedure will be based on the P-y method
of analysis in which the shape and magnitude of the P-y curves in the weathered
rock profiles will be measured and defined. The research plan has three
major components: a) laboratory testing program, b) field testing program
and c) model development. Verification of the developed models based on
the measured field and laboratory data and demonstration of the applicability
of the developed design approach will be performed.
Acquisition of Constructed Infrastructure Testing System
D. W. Johnston, S. H. Ahmad, N. P. Khosla, R. H. Borden, and L. E. Bernold
National Science Foundation and NC State University
1/95 to 12/00
The nation's constructed infrastructure has accumulated a large backlog of needs.
Anticipating the increased national awareness of the deteriorated state of the
nation's constructed infrastructure, the Civil Engineering faculty has developed
the Constructed Facilities Laboratory (CFL) as a part of the new Engineering
Graduate Research Center at NC State. The CFL contains integrated spaces
for research/development in Performance of Large Structural Systems, Fabrication
and Characterization of Cementitious Composites, Evaluation of Construction
Systems, and Geotechnical Techniques and Soil Improvement. This grant
allowed the faculty investigators to acquire state-of-the-art testing equipment
for critical constructed infrastructure research and assessment.
A Unified Approach to Predicting Long Term Performance of Asphalt-Aggregate
Mixtures
Y. R. Kim, R. H. Borden, and Y. Horie
National Science Foundation
9/98 to 8/01
The research objective is to develop test methods and models for predicting
long term performance of asphalt concrete that can account for viscoelasticity,
damage, volumetric/deviatoric coupling, temperature, and aging. The objective
will be accomplished by applying the elastic-viscoelastic correspondence principle
and the continuum damage theory. The constitutive model will be incorporated
into the ABAQUS finite element code and used to predict the response and performance
of laboratory pavements loaded by the Model Mobile Load Simulator. Nondestructive
surface wave tests will be performed to determine the change in material properties
due to fatigue damage growth.
Wave-induced Response and Instability of Seabed
M. S. Rahman
1999, ongoing
Water waves propagating on the ocean creates a cyclic pressure on the ocean
floor that may be significant in shallow water. This in turn induces stress
and pore pressure fields in fluid-saturated seabed, which can cause instability
in the seabed. The general theme of this ongoing research program has
been to understand the mechanism of wave-induced seabed response and instability
and to develop a predictive analytical tool to study this problem. At
present, the following specific problems are being studied: effects of
inertial forces on wave-induced seabed response, wave-induced response of seabed
containing a gas-laden layer, and development of a simple analysis for the coupled
flow and inelastic deformation of seabed including the pore water pressure generation
under cyclic loading.
A Mechanistic Approach to Evaluate Contribution of Prime and Tack Coats in
Composite Asphalt Concrete Pavements
A. A. Tayebali and S. Rahman
NC Department of Transportation (NCDOT)
7/00 to 6/02
The importance of proper AC layer interface bonding cannot be overemphasized
for good performance of AC pavements. A strong bonding between layers
is critical to dissipate shear stresses into the entire pavement structure.
On the other hand, lack of bonding may cause slippage phenomenon and activate
distress mechanisms that will rapidly lead to total failure of the pavement.
The objective of this study is to evaluate the effects of different prime and
tack coats on the bond strength in relation to the thickness of the asphalt
concrete layer. In particular, the distribution and dissipation of shear
stresses under traffic loading and how they affect the interlayer bonding will
be studied. Based on the results of the study, correlation will be developed
between delamination parameters and stress-strain-displacement field.
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