Interpretation and development of top-surface grid in subsurface ground profile using Inverse Distance Weighting (IDW) method for twin tunnel project in Kenny Hill Formation


Author : Mohd Faiz Mohammad Zaki, Mohd Ashraf M. I., Darvintharen Govindasamy, Mohd Hazreek Z. A.Publication : Bulletin of the Geological Society of MalaysiaNo. : 67Page : 91-97Year : 2019DOI : DOI : https://doi.org/10.7186/bgsm67201911


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Bulletin of the Geological Society of Malaysia, Volume 67, June 2019, pp. 91 – 97

Interpretation and development of top-surface grid in subsurface ground profile using Inverse Distance Weighting (IDW) method for twin tunnel project in Kenny Hill Formation

Mohd Faiz Mohammad Zaki1,2, Mohd Ashraf Mohamad Ismail1,*, Darvintharen Govindasamy1, Mohd Hazreek Zainalabidin3

1School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, Penang, Malaysia
2School of Environmental Engineering, Universiti Malaysia Perlis, Perlis, Malaysia
3Faculty of Civil and Environmental Engineering (FKAAS), UTHM, Johor, Malaysia
*Corresponding author email address: ceashraf@usm.my

Abstract: Constrained soil investigation works in tunnel construction projects brings inevitable uncertainties in capturing
the exact subsurface profile. This uncertainty leads to misinterpretation of tunnel analysis, which can later cause unreliable
prediction of settlements trough in tunnel analysis. The initial stage of interpretation of the subsurface soil profile is
generating reliable top-surface grid profile. Increasing the number of boreholes can provide more information for modelling
the grid profile. The profile is conventionally developed using borehole information and survey plan, which are interpreted
manually and sometimes can be erroneous. This situation proves that the lack of method for data interpretation should be
supported with another approach such as Inverse Distance Weighting (IDW). IDW is categorized as a type of deterministic
method for multivariate interpolation with a known scattered set of points. The assign values for unknown points will be
determined by a weighted average of the values available at the known points. IDW interpolation influenced by weight
decreases as the distance increases from the interpolated point. This study focused on the development of top-surface grid
for Klang Valley Mass Rapid Transit (KVMRT) project using data from borehole investigation and survey plan along
the tunnel alignment. Reduced level of boreholes and information from survey plans that were completed for this project
were analyzed. Based on the study results, the Model 2 assigned with exponent 5 for IDW analysis is more preferable
for subsurface ground modelling in tunnel analysis for this particular project.

Keywords: Top-surface grid, subsurface soil profile, Inverse Distance Weighting method, Kenny Hill Formation

DOI : https://doi.org/10.7186/bgsm67201911