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Experimental Study on Inner Interface Mechanical Properties of the ESDCM Pile with Steel Core

Author(s):




Medium: journal article
Language(s): English
Published in: Buildings, , n. 2, v. 13
Page(s): 486
DOI: 10.3390/buildings13020486
Abstract:

The mechanical property of the pile-core–cement-soil interface is a crucial factor affecting the shaft capacity of the expanded stiffened deep-cement-mixing (ESDCM) pile. The research on the characteristics of the steel-pipe–cement-soil interface is very limited, and the conventional concrete–cement-soil interface research results cannot provide direct guidance for the engineering application of the steel-pipe–cement-soil combination pile. Hence, in this study, we employed a model pile with a steel-pipe–cement-soil combination. By using a confining pressure transfer test and an inner interface shear test, the influence of confining pressure on the inner interface and shear deformation of the inner interface were investigated. The results demonstrated that the lateral confining pressure has almost no effect on the inner interface due to the encapsulation of the soil-cement column. The interface shear experienced four stages: the steel pipe small deformation, which is the extra stage compared to the common concrete–cement-soil combination form; the whole pipe compression; the brittle failure; and the shear-slip stage. The peak shear stress at the interface is 194 kPa, and the corresponding pile core top displacement and core bottom displacement are 5.9 mm and 5.4 mm, respectively. The inner interface bond coefficient is only 0.052, indicating that even the smooth steel pipe can work closely with the cement-soil at a low bonding coefficient. Further optimization of the steel-pipe–cement-soil interface structure can be an essential means to improve the mechanical properties of the pile. When the upper load is transferred downward, it spreads around through the cement-soil, and as the load increases, the load that can finally be transferred to the deep part accounts for a relatively small amount, only about 7%. This work promotes the understanding of the interface mechanical properties of ESDCM piles and guides the application of an ESDCM pile with a steel core in practical engineering.

Copyright: © 2023 by the authors; licensee MDPI, Basel, Switzerland.
License:

This creative work has been published under the Creative Commons Attribution 4.0 International (CC-BY 4.0) license which allows copying, and redistribution as well as adaptation of the original work provided appropriate credit is given to the original author and the conditions of the license are met.

  • About this
    data sheet
  • Reference-ID
    10712425
  • Published on:
    21/03/2023
  • Last updated on:
    10/05/2023
 
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