Natural or Mankind Induced Cavities or Caves: Solutions to Live With Them or Do Something About Them

Preconstruction soil improvement by compaction grouting in karst areas can be a cost effective alternate to conventional deep foundation or minipile foundation systerns. This paper presents a case history of compaction grouting for site improvement on portions of a new corporate campus in Chester County, Pennsylvania. The new campu include six-two and three story office buildings, and two-two tory parking structures situated on a site of approximately 809,371 square meter (200 acre). The majority of the site is underlain by bedrock of the Conestoga Formation, which typically includea. micaceous limestone, phyllite, and alternating bed of limestone and dolomite. Carbonite members of the Conestoga formation are soluble and, therefore, susceptible to sinkhole development, and are present under significant portions of the site.