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Development and Lab Calibration of the Pnuematic In-Situ Soil Caving Index Sampler (PISCIS)

The caving/sloughing of sandy layers into drilled shafts is a common and costly phenomenon in the drilling industry. A prototype soil-testing device known as the Pneumatic In-situ Soil Caving Index Sampler (PISCIS) has been developed to test sandy layers above the water table for their propensity to cave/slough into a drilled shaft during the drilling process. The PISCIS fits down a Cone Penetration Test (CPT) hole and uses air pressure to agitate a sample off of the hole wall that is then collected and weighed. Large-scale lab testing was conducted using sand under a variety of simulated overburden pressures and fines contents. The tests were conducted with a dual purpose in mind. First, the tests confirmed the functionality of the PISCIS prototype and its ability to collect samples in a consistent and repeatable manner. Second, the tests resulted in a calibration curve that shows a very strong (nearly exponential) relationship between collected sample weight and the fines content of the test sand; higher fines contents resulted in lower collection weights. The PISCIS was designed to supplement information found in a geotechnical report with information that would specifically inform drilling contractors about potential caving/sloughing hazards found in the stratigraphy.

Identiferoai:union.ndltd.org:CALPOLY/oai:digitalcommons.calpoly.edu:theses-2508
Date01 March 2015
CreatorsGrolle, Michael A
PublisherDigitalCommons@CalPoly
Source SetsCalifornia Polytechnic State University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceMaster's Theses

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