Field device to measure viscosity, density, and other slurry properties in drilled shafts : final report.

Final reportPDFTech ReportBDV25 TWO977-09DensityExcavationMeasuring instrumentsMeasuring methodsSlurryViscosityUnited StatesFlorida. Dept. of TransportationMullins, GrayMullins, MilesUniversity of South Florida. Dept. of Civil and Environmental EngineeringFlorida. Dept. of TransportationCastellano, JuanUS Transportation CollectionProper performance of mineral slurries used to stabilize drilled shaft excavations is maintained by assuring thedensity, viscosity, pH, and sand content stay within state specified limits. These limits have been set either bypast experience, research findings and/or by manufacturer recommended values. However, field slurry testingis time consuming as all measurements are manually performed. With the overwhelming advances in digitaldown-hole devices, it is not unreasonable to assume that slurry property tests are equally applicable to thistrend.The most commonly used test to indicate slurry viscosity is the Marsh Funnel Test which is essentially atimed flow for a fixed volume of slurry to exit a falling head funnel. Using a library of unique pressure versusflow rate responses for a wide range of slurry viscosities, an automated downhole device was designed andtested that incorporated these information to estimate viscosity in the excavation without the need to removeslurry in order to test. Direct measurement of slurry density was also incorporated into the device and the sandcontent was computed from density and the viscosity where the suspended solids that make up the densitystems from both the slurry products and the soil cuttings.The prototype down-hole slurry testing system was shown to be surprisingly easy and fast to usedespite the experimental nature of the device. A shaft sampled at 6 different depths was tested in lessthan 10 minutes. In contrast, conventional, manually performed testing were estimated by contractorsto have taken more than an hour to perform the same number of tests