Time-History Compaction Grouting Data Obtained through Instrumentation: Fid-Bau Portal

Time-History Compaction Grouting Data Obtained through Instrumentation

Geraci, Jeffrey

Compaction grouting is a mechanical ground improvement technique that involves displacement of soil through pressure-injection of stiff mortar-like grout. This type of displacement grouting has been used for several decades to treat weak foundation soils and lift portions of settled structures, and more recently for a wider range of applications, including mitigation of liquefaction potential. Records of injected grout quantities are maintained during production, providing an indication of relative soil displacement with respect to treatment depth. Data have traditionally been collected manually, and typically include grout quantity, average pressure and injection rate for each treatment interval, or "stage". This type of quality control record is often used to estimate hypothetical soil improvement in terms of a displacement ratio; however continuous real-time records of pressure and flow are impractical to obtain through manual methodology. Use of data-logging instrumentation allows for effectively continuous and precise monitoring of pressure and flow during the compaction grouting process. Data collected in this manner not only provide an accurate record of injected grout quantity, but can also be used to identify grout-induced ground deformation, identify and diagnose equipment problems, and evaluate soil response. This paper presents several time-history records of displacement grouting pressure and flow, as well as discussion of associated conditions and possible implications.