Experimental study on the bearing capacity behaviour of branched piling for stabilisation of constructions on peat: A model investigation

Abstract

Due to rapid population growth, construction on peatlands is inevitable. Peat, as a compressible water-saturated and fibre-rich soil with low strength and unique microstructure, presents significant challenges for construction engineering and requires stabilisation using advanced techniques. Conventionally, piles are generally utilised in locations with thick deposits of weak soils. However, their effectiveness in peat can be limited by excessive settlement, reduced load-bearing capacity, higher construction costs, challenges in achieving lateral stability, and potential for disturbance of the peat layers during installation. To address such limitations, this study introduces the innovative concept of branched piling (BP), in which the piles have branches extending from their outer surfaces. Model scale tests were conducted on branched piles installed in large (approximately 1 m³) peat samples collected with minimal disturbance from a site at Silchar in the northeast Indian state of Assam. Extensive testing under static loads revealed a 32 % increase in vertical bearing capacity for BP compared to standard piling. Key variables that significantly influenced BP capacity included branch number (n), branch length (Lb) and top branch inclination angle (α). The results showed that increasing n, Lb and α (up to 45°) enhanced capacity, but capacity was reduced if the α value (inclination) exceeded 45°. This new BP technique provides a practical and effective solution for improving stability, load-bearing capacity and durability of foundations on challenging peat deposits. By tackling the challenges of construction on peat, this method bridges the gap between research advancements and practical engineering applications.