Proceedings of the Deep Mixing 2015 Conference, (DFI)
Effective Sampling, Testing and Specification Approaches for Deep Mixing at Kitimat LNG, BC
Marina S. W. Li, C.Eng., P.Eng., Isherwood Associates, Canada; Randy R. Williams, P.Eng., Golder Associates Ltd., Canada; Brian W. Wilson, C.Eng., P.Eng., Pacific Ground Engineering, Canada; George M. Filz, Ph.D., P.E., Virginia Tech, United States; Donald A. Bruce, Ph.D., D.GE., C.Eng., Geosystems, L.P., United States
In-situ wet grab sampling and post-installation coring of soil-cement structures are typically carried out for Quality Control (QC) and Quality Assurance (QA) of deep mixing (DM) schemes. Wet grab sampling and testing is used to provide data to indicate that performance requirements are being met during production, in advance of coring, which typically occurs at 28 days or later, following installation. While unconfined compressive strength (UCS) tests from wet grab samples provide good production indicators, industry practice often requires that acceptance criteria of soil-cement structures be based on UCS results from representative core samples. This paper outlines the approach adopted for field sampling and QA/QC testing carried out in highly variable subsurface conditions at a site located in northern British Columbia (BC), focusing on post-installation soil-cement coring and strength testing for an extensive deep mixing scheme. A discussion on suitable methods of coring soil-cement structures and appropriate selection of samples for testing that are representative of the in-situ soil-cement structures is provided. This paper also discusses the selection strategy adopted for verification of strength and modulus parameters used for design, providing spatial and time coverage, as well as the acceptance criteria implemented, and provides comparisons with published industry recommendations.
|article #2081; publication #1013 (DM-2015)|