JOURNAL OF ROCK MECHANICS

JOURNAL OF ROCK MECHANICS

Investigating the uncertainty in the geotechnical profile of the tunnel route and its role in the occurrence of surface settlements

Document Type : Original Article

Authors
Ali Kalantari Mazraeno 1
Enayatollah Ranjineh Khojasteh 1
Hamid Chakeri 1
Alireza Talebi Nejhad 2
1 Faculty of mining engineering, Sahand University of Technology, Tabriz, Iran.
2 PhD in mining engineering, Supervisor of Tabriz Metro line 2 project, Tabriz, Iran .
10.22034/irsrm.2024.521320.1041
Abstract
Excavation of metro tunnels in large and densely populated cities is accompanied by fundamental challenges, including maintaining ground stability during excavation and preventing unwanted subsidence. Subsidence is one of the fundamental issues in shallow tunnel excavation in soft soils. This phenomenon can have significant effects on adjacent structures and facilities, highlighting the importance of measuring and investigating the factors affecting it. Estimating the amount of subsidence in tunnel excavation is based on geotechnical parameters; however, the uncertainty in geotechnical data can lead to significant errors in simulation models. In this paper, the effect of uncertainty in the geotechnical profile and its effect on subsidence and even collapse in the eastern route of Tabriz Metro Line 2, which is being excavated in soft marl rock, is initially investigated. In the second part, the effect of geotechnical parameters on the settlement rate has been analyzed using two-dimensional modeling in PLAXIS2D software. The results show that the presence of a very loose sand layer in the upper part of the tunnel and the inability to detect it with basic geotechnical studies has led to over-excavation and the occurrence of ground subsidence in the studied area. On the other hand, based on the sensitivity analysis, the decrease in adhesion and friction angle of the upper layer of the tunnel and the increase in the modulus of elasticity of the layer in which the tunnel is excavated have had the greatest effect on increasing the settlement along the tunnel route.
Keywords
Tunnel collapse
ground settlement
sensitivity analysis
geotechnical parameters
two-dimensional modeling
Subjects
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گزارش مطالعات  ژئوتکنیک تونل و مسیر خط 2 متروی تبریز، سازمان حمل و نقل ریلی تبریز و حومه، 1388.           [16]
     
JOURNAL OF ROCK MECHANICS
Volume 8, Issue 3
Autumn 2024
Pages 85-102