An Innovative Method in Dry Jet Mixing for Improvement of Column Quality in Deeper Layers

The improved depth of dry jet mixing (DJM) in China is limited to being less than 15m due to the limitations of DJM machine; and the strength of soil-cement columns reduces with depth. An innovation method in DJM for improvement column quality in deeper layers in China is presented. A remarkable combined method of DJM with prefabricated vertical drains (PVD), termed DJM-PVD combined method, is innovated and successfully practiced in a highway project on very soft clay in Jiangsu, China. The field experiment results indicate that DJM-PVD combined method makes the installation of DJM columns more easily, especially in deeper layers, enabling the mixing of columns more homogeneously, consequently effectively increasing the strength of DJM columns. In addition, DJM-PVD combined method utilize the lateral pressure and shear stress during the DJM installation as a powerful way of accelerating the consolidation of surrounding clays through PVD, consequently effectively increasing the strength of surrounding clays. The procedures used for DJM-PVD combined method, the instrumentation and the field monitoring data about columns strength, such as standard penetration test (SPT) blow counts and the unconfined compression strength (UCS) of DJM columns core samples, are described. Several potential reasons concerning improvement of PVD on columns strength in DJM-PVD combined method are discussed.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 23p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01044048
  • Record Type: Publication
  • Report/Paper Numbers: 07-3218
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 7:55PM