Prince William County, VA
GTA conducted a geotechnical study, caisson and retaining wall design, and construction observation and testing for the Cardinal Grove Phase I and II site. The Cardinal Grove site is a residential development in Prince William County, Virginia with 158 single family homes. The geotechnical study utilized test borings and laboratory soil testing to evaluate site suitability for development and global stability analysis for several retaining walls and slopes up to 19 feet high. Due to close vicinity of the property line to the retaining walls, several wall options were looked at including MSE block walls and Gravity Walls. Eventually it was determined that soil nail walls with Segmental block facing would be the best fit for the walls along the property line. Due to the height and complexity, one of the retaining walls was deemed Special Inspections by Prince William County.
During construction, GTA provided consultation and materials testing services for the site development, building construction and wall construction. Several unanticipated issues occurred. Due to several streams crossing the site and abnormally wet weather, soil conditions were very wet at the site. In order to keep work moving forward and allow reuse of the onsite soil, GTA devised a lime program to dry the soil enough to use for compaction in the roadway providing a firm, dry access for construction equipment. Additionally, one soil nail wall area was over-excavated past the proposed face of the wall. GTA performed a time-sensitive redesign of the wall and coordinated submission with the County to allow construction to move forward.