Murphy Ground Engineering was commissioned by Network Rail to stabilise and re-grade the southern rail cutting at Churchlands near Harbury, Leamington Spa.
All works had to be structured to reduce disruption and retain access to the local business park on the crest of the cutting.
The works involved:
At pre-planning stage MGE successfully tabled the opportunity to construct a permanent guide beam as the final pile capping beam. This was developed to achieve sizable benefits in waste reduction of both the concrete and steel that is normally associated with temporary guide wall structures. This represented significantly reduced environmental impact, with notable programmed and cost saving benefits.
Over several months this was developed with the project team and the Design Engineer to gain final approval and satisfy the required 120-year design life. The guide beam was constructed in line with the specified concrete and reinforcement requirements and all piles were cast to top of the guide beam structure. After the pile was formed and the main reinforcement installed, 6 starter bars were plunged into the top of the pile to form a structural connection into a finishing cap that was to be poured following completion of the contiguous pile wall.
Retaining access required the development of a contiguous pile wall which reduced the crest line and slope angle of the cutting.
The variable ground profile which included hard to very hard limestone bands prompted the rotary bored technique and the use of heavy-duty tooling and equipment. Together with the strict installation tolerances and closely spaced piles as part of the conforming scheme, a guide beam was required to ensure accuracy of pile placement.
Due to very limited clearance at the front face of the proposed pile line a ‘pinch-point’ consisting of 25 piles also required strict sequencing to close the gap progressively (extreme outer piles working inwards) based on a minimum achieved concrete strength of 20MPa.
Zero concrete waste removal required as the guide beam remains and cropping of piles is not required
120-year design life
Real-time concrete maturity testing streamlined the time taken to process cube sampling and testing. The real-time concrete strengths within the pinch-point zone optimised sequencing and prevented programme delay
The piles once completed were instantly acting monolithically, securing the cutting at the earliest possible stage.
The Ground Engineering team at Murphy offers in-house pile design, value engineering and bespoke technical solutions throughout the UK and Ireland. We have a proven track record of successfully delivering both minor and major works across a range of sectors.