Aarsleff’s Parth Patel captures his latest work movements for us in the Diary of a Graduate Part 2:
This week, it has been my job to review a project at Wednesbury where we are to pile a Retail unit at Gallagher Retain Park. The ground conditions encountered on the previous phase last year proved to be very challenging. As a former landfill site there were many issues concerning obstructions, and in addition there was a dense upper 3m of granular material which made driving piles difficult. It was an advantage to return to a job where we are already familiar with the ground conditions.
With the assistance of Operations Manager Steve Gilbank – we devised a strategy to overcome the previous problems faced. Firstly, we needed to loosen the ground by carrying out Pre-boring of all pile positions. We attended weekly meetings with the client to educate them, and to also ensure that there was a plan in place prior to starting the works. We used a Klemm 709 with relevant auger sizes to pre-bore 262 No. pile positions to approx. 4.5 depth. I was fortunate enough to assist with the pre-boring operations. I learnt that you can easily earn the respect of fellow employees and labourers once you show you are not afraid to do some grafting on site! It was very different to the standard duties and responsibilities of a Contracts Engineer which I was pleased to learn first hand – having previously never seen or carried out pre-boring operations on site.
The pre-boring took approximately a week. This enabled us to identify obstructions and also effectively loosen the upper dense material. We then brought in the Banut 9 Piling Rig with a 4 tonne hammer. I was able to carry out a probing exercise using 200mm & 300mm square precast concrete piles. I noticed on this job that there was a large variation of driven depths of piles. In some cases, where obstructions were encountered at depths, we specified the use of steel tubular piles. This has been effective as steel tubes are able to drive through the existing obstructions, whereas precast concrete piles may have struggled.
Based on the site investigation provided, all piles are founding below the made ground in natural material. Piles at both the deeper and the relatively shallow founding depth have been tested and have demonstrated a minimum working factor of safety of 2.5
The job is currently running ahead of program and the client is happy with progress made so far. The skills and knowledge I have gained by running this job as a contracts engineer have been invaluable to my development.