Evaluation of Stabilization Effect of “T” Shaped Deep Mixing Column from SCPTU Data

Guo-Jun Cai1,a, Song-Yu Liu1, J. Puppala Anand2, Li-Yuan Tong1, Guang-Yin Du1 and Fei Jing1

1Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China.

2Department of Civil Engineering, University of Texas at Arlington, Texas 76019, USA.


Based on stabilization mechanism and factors that affect the column construction quality, a “T” shaped bidirectional soil-cement deep mixing column has been successfully developed, which is proven to be effective and economical. As a part of quality control of field improvement of these columns, seismic piezocone penetration tests (SCPTU), which can provide near-continuous measurements of tip resistance, sleeve friction, and pore pressure induced during the penetration, were utilized. In this paper, field SCPTU tests were performed in the untreated soils and the inter-pile soils between “T” shape bidirectional soil-cement deep mixing columns at Hu-zhou lacustrine clay site in China. Soil properties estimated from the SCPTU data both before and after improvement methods are compared to assess the degree of soil improvement. These results indicate that the use of SCPTU will improve our understanding of the changes in soil behavior achieved by this novel deep soil mixing method.

Keywords: “T” shape; bidirectional deep mixing column; SCPTU; cone resistance; sleeve friction; pore water pressure.

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