A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Quality Assurance of Soil Nailing Works in Hong Kong
Soil nailing has been used extensively in slope improvement works in Hong Kong since the mid-1990s. To date, some 5,000 sub-standard man-made slopes have been upgraded using soil nails. However, once a soil nail has been installed, it is difficult to check its quality in respect of the length of the steel bar and the integrity of cement grout annulus. To enhance the quality control of soil nail installation works, the Geotechnical Engineering Office (GEO) of the Civil Engineering and Development Department in Hong Kong has carried out a study to identify and develop non-destructive means for checking the quality of installed soil nails. Five techniques, including the Sonic Echo method, the Mise-a-la-Masse method, magnetometry, the Electro-Magnetic Induction method and time domain reflectometry (TDR), have been investigated and tried out in the field. The reliability of a TRD test has been established through statistical analyses of laboratory and field test measurements. Among these techniques, TDR was found to be the simplest, relatively reliable, quick and least expensive. In 2004, the GEO introduced TDR to its soil nailing works under the Landslip Prevention and Mitigation Programme during independent site audits. This paper gives an overview of the use of TDR in assessing the quality of steel soil nails with pre-installed wires, where bridging between reliability theory and practice is illustrated. Some cases where TDR has identified anomalies and the corresponding follow-up actions are also described.
Quality Assurance of Soil Nailing Works in Hong Kong
Soil nailing has been used extensively in slope improvement works in Hong Kong since the mid-1990s. To date, some 5,000 sub-standard man-made slopes have been upgraded using soil nails. However, once a soil nail has been installed, it is difficult to check its quality in respect of the length of the steel bar and the integrity of cement grout annulus. To enhance the quality control of soil nail installation works, the Geotechnical Engineering Office (GEO) of the Civil Engineering and Development Department in Hong Kong has carried out a study to identify and develop non-destructive means for checking the quality of installed soil nails. Five techniques, including the Sonic Echo method, the Mise-a-la-Masse method, magnetometry, the Electro-Magnetic Induction method and time domain reflectometry (TDR), have been investigated and tried out in the field. The reliability of a TRD test has been established through statistical analyses of laboratory and field test measurements. Among these techniques, TDR was found to be the simplest, relatively reliable, quick and least expensive. In 2004, the GEO introduced TDR to its soil nailing works under the Landslip Prevention and Mitigation Programme during independent site audits. This paper gives an overview of the use of TDR in assessing the quality of steel soil nails with pre-installed wires, where bridging between reliability theory and practice is illustrated. Some cases where TDR has identified anomalies and the corresponding follow-up actions are also described.
Quality Assurance of Soil Nailing Works in Hong Kong
Cheung, Raymond W. M. (author)
Geo-Risk 2017 ; 2017 ; Denver, Colorado
Geotechnical Safety and Reliability ; 350-373
2017-06-01
Conference paper
Electronic Resource
English
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