Journal Published Online: 02 May 2019
Volume 43, Issue 2

Alignment of Vertical and Inclined Jet Grout Columns for Waterproofing



Good overlapping among jet grout columns is crucial for the success of waterproofing in the ground. Drilling alignment, column spacing, and diameter of jet grout columns are the controlling factors of good column overlapping. This study evaluated the drilling alignment of vertical and inclined jet grout columns using field-measured alignment data and statistical analysis. A three-dimensional (3-D) image of a jet-grouted mass was established by combining the measurement results of drilling alignment and jet grout column diameter from the trial test. The 3-D image was used to examine the overlapping of the jet grout columns and identify possible locations of windows (non-grouted zones) in the jet-grouted mass. Vertically drilled jet grout holes maintained excellent alignment, with an average estimated inclination angle of 0.43° and standard deviations of 0.11°. However, to avoid underground obstacles, inclined drilling is often required. An inclined drill jet grout hole can easily deviate from its designed drilling alignment because of gravity and result in poor overlapping and potential windows. The average estimated inclination angle and standard deviation of inclined drilling were approximately three times those of vertical drilling.

Author Information

Cheng, Shih-Hao
Taiwan Building Technology Center, National Taiwan University of Science and Technology, Taipei City, Taiwan
Liao, Hung-Jiun
Department of Civil and Construction Engineering, National Taiwan University of Science and Technology, Taipei City, Taiwan
Yamazaki, Junichi
SANSHIN Corporation, Tokyo, Japan
Wong, Ricky K. N.
Taipei Branch, SANSHIN Corporation, Taipei City, Taiwan
Iwakubo, Takeshi
Taipei Branch, SANSHIN Corporation, Taipei City, Taiwan
Pages: 14
Price: $25.00
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Stock #: GTJ20180324
ISSN: 0149-6115
DOI: 10.1520/GTJ20180324