DG Geotechnical Engineering Company was awarded a foundation contract for a housing project in Taixing city in Zhejiang province. The design specified a Soil Mix Wall for the excavation pits retaining wall. SMW walls are a popular and trusted method in China, concrete is mixed into the soil and H-beams are inserted into the mix. The steel beams are coated with a substance that prevents the concrete to adhere to its surface so that after completion of the foundation project the H-beams can be extracted and reused. The H beams chosen for this specific project were 700mm wide and 24m long. We’ve been reporting about adjustments to the technique that our clients are introducing.

In this particular case the client first used a 90kw electric hammer to drive the H beams into the soil mix and then changed to a hydraulic vibro. Though cheap to rent, the electric hammers low vibration frequency caused problems straight away. The soil mix wall was installed a mere 8 meters away from adjacent housing blocks. As the electric hammers operating frequency was equal to the resonance frequency of the soil， the residents were quite shaken about the vibrations they were feeling and worried about the cracks that appeared in their buildings. The client, a reader of our blog， knew about ICE’s resonance free vibratory hammers and asked for a rental quotation for the 20RF as he believed this would solve the problem. But, now that RF vibrating technology has gained wide acceptance in the market， all rental units were out and the client opted for a normal frequency 416L instead. The test piles driven with the 416L proved sufficiently undisruptive to the structures in the vicinity of the Soil Mix Wall to do the job, so that the client was able to finish the project with a normal frequency hydraulic vibratory hammer.

Time and again ICE’s high frequency and variable moment RF hammers have proven their dexterity working in urbanized areas. Electrically powered hammers are slowly but surely losing ground. If you want to be in at the forefront of this market trend give us a call today so that we can share our expertise with you!