Vibratory hammer assisted bore piling has quickly become a well-established construction method across China. The benefits are obvious: increased daily production rate no bentonite on site and better quality piles. 

Casing should be driven by vibratory hammers with a double clamping system to ensure the casing is driven down vertically yet many small contractors cut corners by using excavator mounted sheet pile hammers to drive (or often just push) small diameter casings haphazardly into the soil.

Bored piles are steadily increasing in length and diameter. Following the example of Hong Kong and Macao diameters ranging from 1800-2800mm are becoming the new standard slowly surpassing the popularity of mini bore piles (below 1 meter diameter). Larger diameter piles have a higher lateral load and vertical load capacity and a stronger pullout ability. Larger diameter piles are also more earthquake resistant! These piles are the ideal foundation for the super-structures that are now being built all over China. The cost of these foundations (material and equipment cost) is increasing and so is the cost of pile failure. This is why bore pile rig operators are now looking for reliable equipment to drive down these heavy casings which can weight up to 20t.

The most sought after vibratory equipment for this application are ICE’s 815C and 1412C models. These two hammers are suitable for driving casings with a diameter in the range of 450-2940mm. The hammers are fitted with a double clamping system and can drive and extract the casings. In soft soils that collapse easily we recommend driving the casing until refusal and then bringing in the bore rig to build the pile.

In very difficult soil conditions (hard stones) we recommend the client to first do a round of boring to loosen up the soil then to vibrate the casing into the soil and empty the casing with the bore rig.

Luzhou Xingcheng Real Estate Development Corporation won a real estate project in the city of Luzhou. The foundation design was for 40m deep 2m diameter foundation piles. There were 6 Sany 280 bore pile rigs on site to build these. Due to the soil conditions the client chose to drive 20m long steel casings for each pile. Deep and wide excavations like these need the support of an outer casing to protect from collapse and to guarantee the integrity of the pile. Naturally the search for suitable equipment led to ICE a brand that has established itself as an expert in this foundation type because of its high reliability and driving precision.

Considering the pile weight and length the client chose the larger 1412C hammer over the 815C. The 1412C offers 230t driving force and an 80t line pull capacity. The 1412C is a good match for the larger bore pile rigs such as the Sany 280 available in the market.

The working method on this construction project in Luzhou is very representative for what we encounter in other markets such as the Pearl River Delta in Southern China. In the PRD bore pile diameters are also increasing some special challenges there are the high rates of backfill and the silty clay and sandy silt conditions which impact the stability of the borings which need to be solved by driving temporary steel casings with a vibratory hammer. In the geographical area of Yunnan-Guizhou-Sichuan the porous lime stone ground that is filled with caves and cavities form the main reason for driving temporary casings before building a bored pile.

Bore pile friends whether its hard soil or soft soil layers or caves or boulders that complicate your job don’t forget we are at your side to help you! Share if you agree!