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

CPT success in New Zealand

A new cone penetration testing (CPT) service in New Zealand is proving popular with postearthquake reconstruction projects in Christchurch.

Lankelma took its CPT rig out to the region in May to help provide essential information for the rebuild. “I was constantly being questioned about our ability to penetrate the regional shallow gravels and, after many years of working through the river terrace deposits within the London Basin, I felt we could manage the gravel layers here,” says Lankelma engineering director Carlton Hall.

Following good performance using a conventional piezocone, Lankelma was challenged with a site within Christchurch’s Central Business District, where very dense shallow gravels have previously been encountered.

Very dense gravels were reached at 6.5m but Lankelma advanced “pre-push” casing to 9.9m, which was then extracted and the piezocone re-inserted to progress to a depth of 23m into the underlying sands.

Tonkin and Taylor supervising engineering geologist Richard Phillips added that the data has proved to be very useful during the rebuilding work. “The rig is able to puncture through the gravels which is something we had been hoping for,” he says.

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.