Abstract
Piezoballs, which are full-flow ball penetrometers incorporating pore pressure measurements, are an attractive soft soil characterisation tool as they allow measurement of the intact and remoulded strength and the consolidation coefficient in a single test. The merit of full-flow penetrometers as a reliable tool that is superior to the cone in quantifying the strength of soft clay is gaining acceptance. Much of the recent focus on piezoballs has been on the pore pressure measurement location. Prompted by recent studies that highlight the merit of measuring pore pressure concurrently at more than one measurement location, this paper considers a new centrifuge-scale piezoball, with simultaneous pore pressure measurement at the equator and mid-face positions. Results from centrifuge tests in normally consolidated kaolin clay form the basis for the examination and yield coefficients of consolidation that are consistent with values derived using a number of different methods. Although the mid-face position appears to be the more sensible pore pressure measurement position for dissipation tests, consideration of the values measured at both positions provide strong indications of the drainage response during penetration that is shown in the paper to be important for deriving coefficients of consolidation from subsequent dissipation phases.
Highlights
Most of the early research into full-flow penetrometers focused on their use as a strength-profiling tool (Chung and Randolph, 2004; Stewart and Randolph, 1991, 1994; Watson et al, 1998)
Measurement of intact and remoulded shear strength and the consolidation characteristics of soil are important parameters required for the design of geotechnical structures, those located offshore
This paper considers centrifuge data obtained with a new model scale piezoball penetrometer that simultaneously measures pore pressures at both the equator and mid-face positions
Summary
Most of the early research into full-flow penetrometers focused on their use as a strength-profiling tool (Chung and Randolph, 2004; Stewart and Randolph, 1991, 1994; Watson et al, 1998). The benefits of measuring pore pressure in one device rather than from two separate tests include reduced testing times and greater reliability in the pore pressure profiles given that even with the attempts made to ensure a homogenous sample, there may still be some differences between test locations The potential for this new device to measure intact and remoulded strength and the coefficient of consolidation accurately in a single test is examined through standard penetrometer tests and tests involving cyclic remoulding episodes, penetration pauses and penetration velocity changes
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Physical Modelling in Geotechnics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
