Case Study Template Drainforce Ltd, Unit 2, Heol Ffaldau, Bridgend, CF312AJ

Case Study Number: Case Study 1 Title: Llanwern Pile Cutting Feasibility

Client Details: Lewis Engineering

Location of Services: Newport

Contract Value: Open

Contract Dates: 2020

Scope of Services:

● Pile Cutting ● Concrete Cutting ● Obstruction Removal

Relevance to: Could be used to cut out Pile In Llanwern. Introduction Drainforce were approached by a client to look at options to cut out a steel pile that has been driven through a large diameter brick sewer which is also located adjacent to the Swansea to Paddington Railway line. The estimated cost for dig down repair solution is in excess of £1.5m.

Site Location Plan

Case Study Template Drainforce Ltd, Unit 2, Heol Ffaldau, Bridgend, CF312AJ

Objective The objective was to look at a non dig solution to cut out the steel pile SWM/213/173-MA 762mm external diameter, 16mm thick, steel grade is S355 with natural ground in the centre of the pile. A manentry cutting operation was not an option due to risk of the brick sewer collapsing and the potential of a head waste water and debris upstream from the pile. Cutting out the pile would allow the sewer to be reinstated as operational. Market Availability Extensive market research was undertaken on equipment availability to cut out the pile without man entry. This was concluded as no availability for any cutting equipment that would cut the steel pile. Feasibility Drainforce have a top specification robotic hydro cutter and the solution was consider to develop a cutting solution based on the Hydro cutter but with brake design, jetting nozzle designed to accommodate ultra-high pressure water injected with garnet while adding to the flow ultra-high pressure water injected with garnet grit that would mix with the water and would provide an abrasive mixture to penetrate the steel. The speed of cutting was essential which required enough time to penetrate the steel before moving the cutting nozzle. This was critical in the design because if the steel was not fully penetrated the abrasive mixture would bounce back and starting cutting the robot itself. Calculation of the distance we would need to position the cutting head to be able to cut the pile was also critical. Testing Drainforce had manufactured a steel pile to replicate the pile in the sewer so the cutting was being tested on an identical pile in terms of diameter and thickness. Testing programme was undertaken in a 2 stage approach. Stage 1 Testing - Factory Environment Drainforce working in collaboration with a manufacturer used the jetting nozzle design below for the cutting which included a side inlet for the aggregate to be added to make the abrasive mixture. The testing would also confirm traverse speed we could cut the pile and also what distance away we would need to position the cutting head to be able to cut the pile. Jetting Nozzle Design With Side Aggregate Inlet below:

Side View Rear View Side View Set up of trial equipment The pile was positioned in the testing bay and a linear nozzle manipulating tool was attached. The designed pressure was set and the garnet mix tae was set.

● Nozzle position 1 First cut with a stand-off distance close to the pile, the traverse (cutting) speed as per initial design was set and the test successfully penetrated the steel pile.

● Nozzle position 2

Case Study Template Drainforce Ltd, Unit 2, Heol Ffaldau, Bridgend, CF312AJ

A second cut with a stand-off distance further from the pile and a change to the traverse speed was set which also penetrated the steel successfully. The cut was not as clean as nozzle position 1.

● Findings The testing confirmed that the pile could be cut and that Nozzle 2 test was longer to penetrate the steel and was not as clean cut as nozzle position 1.

Robot Multi Movement Design Withstand Ultra High Pressure Cutting was designed and built as show below:

Case Study Template Drainforce Ltd, Unit 2, Heol Ffaldau, Bridgend, CF312AJ

Stage 2 Testing - Mock Sewer/Pile Testing Drainforce Depot Bridgend A dynamic risk assessment was method statement was implemented and an exclusion zone was set up at our depot to replicate the principles of cutting remotely from within the sewer and cutting the and the pile was position vertically adjacent to the sewer as layout below.

Conclusion The testing confirmed that the cutting solution has successfully achieved the required objective and can cut the steel pile from within a sewer working remotely. This solution can be used in many situations to cut out hard materials and obstructions which is a new innovation and is a significant saving for clients, it's quicker, less disruption for customers, the health and safety risk of man entry cutting has been removed with this being done remotely. Drainforce are able to offer a post cutting cleaning of the drainage system and CCTV, and also after the obstruction has been cut out and removed the drainage system can be lined which will give a 70 year guarantee.

Case Study Template Drainforce Ltd, Unit 2, Heol Ffaldau, Bridgend, CF312AJ