M20 J3 – J5 Smart Motorway Programme
The M20 motorway between Junction 3 and Junction 5 comprises a 10km stretch of traditional motorway with dual 3 lane running.
The scheme proposed by Highways England is to implement a Smart Motorway, where, as part of the scheme, the hard shoulder will be converted into a running lane to add further capacity as All Lane Running (ALR). These works will require the construction of additional traffic control gantries and the provision of Emergency Refuge Areas (ERAs). The motorway is likely to require location specific widening of the earthworks to accommodate these new structures and ERAs.
The aim of the ground investigation was to provide an assessment of the ground conditions for the design of earthworks widening and foundations for the new gantries, signs and other additional infrastructure. This included the strength and compressibility characteristics of the superficial and solid geology. Details of the chemical aggressivity of the ground were required to allow appropriate design of buried concrete.
The investigation comprised the formation of over 70no Cable Percussive boreholes, 29no of these extended by Rotary Coring with recircualted water & mud flushes. In addition 23no Dynamic Sampling holes were copleetd where access prevented the use of Cable Percussive rigs, along with the excavation of 88no trial trenches to provide large scale information on near surface geology and bured services.
Geoenvironmental samples were taken throughout works, to prove safety and design risk information for construction works. Samples were screened onsite by headspace analysis for volatile content before dispatch for further analysis. All Geotechnical and Geoenvironmental testing was undertaken in UKAS accredited facilities.
Works were undertaken under traffic management, facilitating day shift work. Our works were closely coordinated with other site users, including surveyors and vegetation management teams, to maintain the safety of all involved, and efficient working arrangements.