Geological assessment for tunnel excavation under river with shallow overburden using surface site investigation data and electrical resistivity tomography
Document Type
Article
Publication Date
1-1-2019
Abstract
Tunnelling is a challenging task as many geotechnical uncertainties involved during construction, especially under a river crossing with shallow overburden. This study focussed on geological assessment for the New Austrian Tunneling Method excavation that crosses under Kerau River with shallow overburden. 3D filtered tunnel models using Boolean filter for rock mass weathering grade, rock quality designation, and Lugeon value are developed. Results predict that 53.3% of the tunnel excavation under the Kerau River crossing are highly weathered rocks (Grades III and IV), and 64.51% are in the moderately to highly fractured zone (0%–75% RQD) along the roof of the tunnel granitic bedrock. The Lugeon value models show that 71.64% of the excavating rocks possess a Lugeon value of 5–50 (6–60 × 10−5 cm/s), which denotes considerably high permeability. 2D electrical resistivity tomography is used to verify the permeability results from the Lugeon test. © 2019 Elsevier Ltd
Keywords
Geological assessment, NATM tunnel, Filtered tunnel model, Lugeon value, Rock mass weathering grade, Rock quality designation
Divisions
fac_eng
Funders
Fundamental Research Grant Scheme of the Ministry of Education Malaysia : Analysis of Rock Burst Behaviour under Overstressed Rock in Deep Tunnel Excavation across the Titiwangsa Range, Malaysia (Grant No. 203/PAWAM/6071259),RU Grant of University of Malaya (Grant No. GPF026A-2018)
Publication Title
Measurement
Volume
144
Publisher
Elsevier