SR 0029, Section SNK Sinkhole Remediation Project

E. Whiteland Township & Charlestown Township, Chester County, PA


Penndot District 6-0
7000 Geerdes Blvd.
King of Prussia, PA 19406



April 2017





The S.R. 0029, Section SNK project is located along Route 29 between the PA Turnpike Slip Ramp and Yellow Springs Road. Over the past 10 years, this portion of Route 29 has been experiencing pavement failures caused by localized sinkholes. The sinkholes are being caused by failures in the limestone subgrade located beneath the roadway. The subgrade failures are being caused by the movement of groundwater and surface water within the subgrade.

The approach to the problem is twofold. First, eliminate surface water from infiltrating and concentrating in areas so as to wash soil into existing or future limestone crevices under the roadway. Secondly, excavate and replace soil that is susceptible to this activity.

TPD, in combination with our subconsultant A.G.E.S., developed a design which involved removing the existing poor subgrade material down to bedrock and replacing the material with a combination of cellular concrete, clean rock, geosyenthetics, geogrid and geomembrane materials. Additional design elements included the lining of pipe to eliminate leakage and the addition of base drain to capture any water which migrates into the pavement subbase.

TPD was responsible for Preliminary Engineering, Final Design and Construction Services. This included the development of Construction Plans, Traffic Control Plans, Temporary Signal Plans, Signing and Pavement Marking Plans, and utility coordination.

Limerick Township, Montgomery County, PA

Service(s): Highway Design. Construction Management and Inspection Services, Traffic Signal & ITS Systems Design & Environmental Services & Permitting
Client(s): Limerick Township

Municipality of Princeton, County of Mercer, NJ

Service(s): Highway Design
Client(s): County of Mercer

East Marlborough Township, Chester County, PA

Service(s): Multimodal, Complete Streets & Mobility Services, Traffic Signal & ITS Systems, Municipal Engineering Services, Highway Design
Client(s): East Marlborough Township