Previous research: Dr Zhou conducted a series of tests involving CDG dense fill model slopes reinforced with different sizes of nail heads including grillage, which were destabilized by controlling long-term transient seepage in the centrifuge.
The prototype slope angle and height were 650 and 15 m, respectively. Pore water pressures, slope deformation, axial nail forces and contact pressures between the soil and nail heads were measured. Pore water pressure transducers were modified into tensiometers to measure high suction in the centrifuge.
A four-stage procedure was developed to saturate the tensiometers. Furthermore, an experimental framework was established to identify whether a tensiometer had been desaturated. Three-dimensional coupled numerical simulations using ABAQUS were conducted to back-analyse the centrifuge test results. The three-dimensional numerical simulations considered the coupled effects of soil deformation and pore water pressure changes. It was found that a global failure occurred in the unreinforced slope after being subjected to long-term transient seepage. Installation of soil nails prevented global failure, but not tension cracks at the crest. The presence of nail heads prevented the global failure and the formation of the crack after even over the equivalent of two years of transient seepage.
With the greater sizes of nail heads, (a) crest settlements decreased, (b) the mobilised axial force at the nail head on each nail and a total of each mobilised maximum axial nail force (Tmax) increased, (c) the location of the Tmax shifted towards the slope surface, and (d) the normalized contact pressures increased at the quasi-steady state. The global failure which occurred in the unreinforced slope in the centrifuge was reasonably consistent with numerical simulations. General trends in crest settlements and axial forces at the quasi-steady state were also captured in the numerical simulations.
Current work: Dr Zhou is a consultant at Arcadis (doing both design and design checking) for reclamation works, tunneling/cavern works (including TBM, cut & cover, IMT, drill & break), excavation and lateral support works, artificial ground freezing, natural terrain hazard assessment and studies, ground investigation planning, geotechnical planning review etc. Projects he has worked on include:
|Contract No. EP/SP/66/12: Integrated Waste Management Facilities Phase 1, HK$31,398.1M, Designer|
|Contract No. EP/SP75/14: Low-Level Radioactive Waste Storage Facility Follow-On Contract (HK$125M), Independent Consultant|
|Contract No. 15/WSD/10: Expansion of Tai Po Water Treatment Works and Ancillary Raw Water and Fresh Water Transfer Facilities – Design and Built of New Stream II, Independent Design Checker|
|Agreement No. CE38/2008 (HY): Kai Tak Development – Trunk Road T2 and Infrastructure at South Apron – Investigation, Design and Construction, Hong Kong (HK$10B est.), Engineer|
|Contract No. HY/2011/03: Hong Kong-Zhuhai-Macao Bridge Hong Link Road – Section between Scenic Hill and Hong Kong Boundary Crossing Facilities (HK$8.88B), Independent Design Checker|
|Agreement No. CE33/2014(WS): Feasibility Study on Relocation of Diamond Hill Fresh Water and Salt Water Service Reservoirs to Caverns, Kowloon (HK$500M, est.), Consultant|
|Agreement No. CE53/2015 (WS): Eighth Safety Review of Small Service Reservoirs – Investigation (HK$8.95M), Consultant|
|Contract No. WIL703: MTR Western Island Line – SHW to SYP Tunnels (HK$1.7B), Designer|
Dr Robin Zhou | PhD, MEng, BSc, CEng MICE, MHKIE, RPE(GEL, CVL)