Geomechanical model test for analysis of surrounding rock behaviours in composite strata
Due to the large differences in physico-mechanical properties of composite strata, jamming, head sinking and other serious consequences occur frequently during tunnel boring machine (TBM) excavation. To analyse the stability of surrounding rocks in composite strata under the disturbance of TBM excav...
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doaj-e83e58370e1b48a4bd7808f0b4b37a722021-07-13T04:08:54ZengElsevierJournal of Rock Mechanics and Geotechnical Engineering1674-77552021-08-01134774786Geomechanical model test for analysis of surrounding rock behaviours in composite strataLinken Shi0Hui Zhou1Ming Song2Jingjing Lu3Zhenjiang Liu4State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Corresponding author. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China.CCCC Second Highway Consultants Co., Ltd., Wuhan, 430056, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, ChinaDue to the large differences in physico-mechanical properties of composite strata, jamming, head sinking and other serious consequences occur frequently during tunnel boring machine (TBM) excavation. To analyse the stability of surrounding rocks in composite strata under the disturbance of TBM excavation, a geomechanical model test was carried out based on the Lanzhou water supply project. The evolution patterns and distribution characteristics of the strain, stress, and tunnel deformation and fracturing were analysed. The results showed that during TBM excavation in the horizontal composite formations (with upper soft and lower hard layers and with upper hard and lower soft layers), a significant difference in response to the surrounding rocks can be observed. As the strength ratio of the surrounding rocks decreases, the ratio of the maximum strain of the hard rock mass to that of the relatively soft rock mass gradually decreases. The radial stress of the relatively soft rock mass is smaller than that of the hard rock mass in both types of composite strata, indicating that the weak rock mass in the composite formation results in the difference in the mechanical behaviours of the surrounding rocks. The displacement field of the surrounding rocks obtained by the digital speckle correlation method (DSCM) and the macro-fracture morphology after tunnel excavation visually reflected the deformation difference of the composite rock mass. Finally, some suggestions and measures were provided for TBM excavation in composite strata, such as advance geological forecasting and effective monitoring of weak rock masses.http://www.sciencedirect.com/science/article/pii/S1674775521000135Model testTunnel excavationComposite strataDeformation and failure mechanismStability analysis |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Linken Shi Hui Zhou Ming Song Jingjing Lu Zhenjiang Liu |
spellingShingle |
Linken Shi Hui Zhou Ming Song Jingjing Lu Zhenjiang Liu Geomechanical model test for analysis of surrounding rock behaviours in composite strata Journal of Rock Mechanics and Geotechnical Engineering Model test Tunnel excavation Composite strata Deformation and failure mechanism Stability analysis |
author_facet |
Linken Shi Hui Zhou Ming Song Jingjing Lu Zhenjiang Liu |
author_sort |
Linken Shi |
title |
Geomechanical model test for analysis of surrounding rock behaviours in composite strata |
title_short |
Geomechanical model test for analysis of surrounding rock behaviours in composite strata |
title_full |
Geomechanical model test for analysis of surrounding rock behaviours in composite strata |
title_fullStr |
Geomechanical model test for analysis of surrounding rock behaviours in composite strata |
title_full_unstemmed |
Geomechanical model test for analysis of surrounding rock behaviours in composite strata |
title_sort |
geomechanical model test for analysis of surrounding rock behaviours in composite strata |
publisher |
Elsevier |
series |
Journal of Rock Mechanics and Geotechnical Engineering |
issn |
1674-7755 |
publishDate |
2021-08-01 |
description |
Due to the large differences in physico-mechanical properties of composite strata, jamming, head sinking and other serious consequences occur frequently during tunnel boring machine (TBM) excavation. To analyse the stability of surrounding rocks in composite strata under the disturbance of TBM excavation, a geomechanical model test was carried out based on the Lanzhou water supply project. The evolution patterns and distribution characteristics of the strain, stress, and tunnel deformation and fracturing were analysed. The results showed that during TBM excavation in the horizontal composite formations (with upper soft and lower hard layers and with upper hard and lower soft layers), a significant difference in response to the surrounding rocks can be observed. As the strength ratio of the surrounding rocks decreases, the ratio of the maximum strain of the hard rock mass to that of the relatively soft rock mass gradually decreases. The radial stress of the relatively soft rock mass is smaller than that of the hard rock mass in both types of composite strata, indicating that the weak rock mass in the composite formation results in the difference in the mechanical behaviours of the surrounding rocks. The displacement field of the surrounding rocks obtained by the digital speckle correlation method (DSCM) and the macro-fracture morphology after tunnel excavation visually reflected the deformation difference of the composite rock mass. Finally, some suggestions and measures were provided for TBM excavation in composite strata, such as advance geological forecasting and effective monitoring of weak rock masses. |
topic |
Model test Tunnel excavation Composite strata Deformation and failure mechanism Stability analysis |
url |
http://www.sciencedirect.com/science/article/pii/S1674775521000135 |
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