Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Corroded nail heads have been treated

I read with interest the article by Tony Barley in your April 1998 issue entitled 'Can corrosion rule slides?' I am grateful to Mr Barley for subsequent correspondence in which he identifies the location of the soil nails where he observed corrosion in September 1996.

Based on our records, these soil nails were not galvanised and had exposed heads. They were installed in 1979 as temporary remedial works to prevent further subsidence of a garden lawn platform behind a retaining wall.

The design details of these soil nails do not meet the current design standards, especially with regard to galvanisation of the steel and encapsulation of the soil nail head. In 1984, 16 of the nails were exhumed and it was found that the exposed portions of the nails were significantly corroded whereas the portions encased in cement grout were clean and without any rust.

In 1996, the area was redeveloped and the garden lawn platform was lowered to about half the original height. The heads of all soil nails concerned at the site are now covered by sprayed concrete.

YC Chan

Government geotechnical engineer

Geotechnical Engineering Office

101 Princess Margaret Road

Kowloon

Hong Kong

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.