Quantitative Assessment of Drilled Shafts Base-Cleanliness Using the Shaft Quantitative Inspection Device (SQUID)

摘要

Shaft base cleanliness is a widely discussed topic regarding quality control and quality assurance of the drilled shafts. Several existing tools and approaches have been proposed and published to assess the shaft base cleanliness. In the drilled shaft construction industry, in situations where the stability of the soil material is questionable, and the groundwater table is shallow, the wet construction method approach is primarily used. In this method, slurry is placed into the hole to maintain stability in the excavation (i.e., drilled hole) and to impede the intrusion of groundwater into the excavation. During the drilling process, cuttings, debris, and sediments are accumulated at the bottom of the hole which can impact the performance of the deep foundation element. The bottom of the drilled hole is typically cleaned using an airlift system and/or cleaning buckets to ensure the drilled shafts base cleanliness. After this process is completed, the conditions at the drilled shaft's base can be quantitatively assessed using shaft base inspection devices. This paper presents results of a side-by-side comparison of mini-SID and shaft quantitative inspection device (SQUID) tests performed for seven drilled shafts installed in intermediate geomaterial. The effort associated with data collection, debris definition, and measurements are presented and discussed in detail.