Sustainable design at transition rigid piled embankment with surcharged vertical drain over soft ground

Abstract

the repair of undulating road involves enormous time and high cost for repetitive remedial works over the time. intolerable differential settlement is the main cause of the undulating roads. differential settlement frequently occurs at the intersection of different ground pressure, ground condition, ground treatment and foundation system such as surcharged prefabricated vertical drain (spvd) and rigid piled embankment which shall be arrested to overcome the undulating road problem. in this research, the intersection of spvd at transition of rigid piled embankment is introduced to regulate post construction differential settlement between the two conventional ground treatments. this dissertation presents analytical, numerical and field studies of a sustainable design for high and long filled embankment over soft clay at structure approach. generally, soil settlement is computed based on equivalent raft method and settlement equation proposed by terzaghi and boussinesq. prefabricated vertical drain is designed based on method proposed by janbu. whilst, numerical design was modelled in plaxis 2012 using soft soil creep (ssc) model with embedded pile row and improved vertical hydraulic permeability, kve. instrumented full scale field study was also performed to validate the performance of the proposed system where settlement gauges and settlement markers were installed to monitor the ground surface settlement. sustainability of the proposed ground treatment approach is quantified in terms of differential settlement, cost and time of construction in comparison to malaysia industry’s conventional ground treatments. the proposed intersection ground treatment reduces post construction total settlement by about 80% to 95% of the total settlement as compared to conventional transition piled embankment. meanwhile differential settlement is controlled within the limit of 1:500 throughout the filled embankment. the cost of construction and maintenance works is about 20% lower than conventional piled embankment. the construction time of the proposed system is about 20% to 30% faster than the conventional piled embankment systems. hence, the proposed system is a sustainable system in term of performance, cost and time of construction.