| Autor: |
Bai, Y., Salcher, M., Fusee, R., Bentley, T., Kumar, A., Trim, M. |
| Předmět: |
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| Zdroj: |
EA National Conference Publications; 2023, p886-900, 15p |
| Abstrakt: |
Rozelle Interchange is one of the most complex underground motorways constructed in Australia. Its unique multilevel underground interchange creates engineering challenges in the way tunnel excavation and rock deformation interact with the ground support. The tunnels and caverns, up to 29 m wide and 24 m high, of the Sydney motorway were excavated in Hawkesbury Sandstone at depths between approximately 5 m and 70 m. During the construction of the 23 km of tunnels, occurrences of rock bolt shearing were observed. Shearing is caused by excavation-induced stress relief movement along geological defects. During design and construction of tunnels, shearing is a key consideration because of its potential impact on the durability of the protective sheath of permanent rock bolts at small magnitudes as well as the structural capacity of the rock bolts at larger magnitudes. Shearing was monitored and quantified during tunnel excavation using video inspections of endoscope holes drilled into the tunnel crown and using tools to reach uphole and measure the displacement at the sheared plane. Shearing was observed in different geological settings at various depths and was sometimes associated with regional scale geology such as dykes and faults. Most shearing occurred along subhorizontal bedding partings, laminite bands and siltstone rip-up clasts. Recorded shear movements exceeding the 10 mm rebolting trigger level were observed on this project, and multiple shear planes within a single endoscope hole were detected. At some locations, temporally successive shearing events occurred. This paper presents shearing detection and quantification methods, and observations during excavation, and describes how shearing was managed during construction. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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