Theme 3: The Business Side of InstrumentationStaged Embankment Construction Using In-Situ Instrumentation ReturnsBenefits To Contractor and Cost Savings to the Owner

摘要

The Piedmont Triad International Airport (PTIA) is undergoing anrnexpansion including a new runway (Runway 5L-23R) and taxiway (Taxiway E) as arnresult of the construction of a regional hub for Federal Express. Part of thernconstruction of the associated Taxiway E includes the construction of thernembankment over a wetlands area in an alluvial floodplain. The presence of softrnground in the wetlands area required careful consideration of the effects ofrnconstruction, due to permitting requirements. An instrumentation program wasrnimplemented to determine the fill placement rates or appropriate waiting periodsrnduring fill placement, and to prevent slope failures from occurring. This paperrnhighlights key features of the instrumentation system. It describes therninstrumentation system that was installed, the results obtained to date, and practicalrnissues that were addressed during construction. The grading plans for the projectrnindicate the construction of an 18 meters (60-feet) high earth embankment over thernexisting soft ground. The subsurface exploration indicated the soft ground profile tornconsist of an upper zone of alluvial soil underlain by a residual soil profile. A hybridrnground modification technique was used to stabilize the soft ground, allowingrnconstruction of the Taxiway E embankment without more intensive efforts. The usernof ground stabilization to provide a working platform in conjunction with toe bermsrnto maintain slope stability and wick drains to accelerate drainage, strength gain, andrnsettlement offered benefits to all members of the project team. The instrumentationrnprogram resulted in both material and time savings, by allowing for the modificationrnof the design based on field conditions, and reducing or eliminating the waitingrnperiods between fill placement phases.