Static and Dynamic Characterization of Hemic Peat at Kailashar, Tripura

Peat is categorized as soft natured material which is primarily comprised of decomposed wood, plant and animals remains. Peat is considered to be a challenging material for geotechnical and structural engineers owing to its high water content, presence of large voids, low strength and high settlement values. Apart from static parameters, dynamic parameters of peat has been identified as a major source of uncertainty in the assessment of seismic vulnerability of a region. The present study deals with peat natured soil encountered at a bridge section of Kailasahar-Kurti, located in the Unakoti district of North Eastern state of India, Tripura. A total of 35 boreholes were carried out across the entire stretch to identify the subsoil profile. Retrieved samples from subsoil exploration were identified as hemic peat, which were undergone static and dynamic characterization. Shear wave velocity (V_s), an important dynamic parameter was evaluated by non-destructive (NDT) ultrasonic pulse velocity (UPV) test on both stabilized and unstabilized samples. Stabilization was carried out by mixing lime at varying percentages. Results obtained from the test clearly indicates peat to have low V_s, which tends to improve upon stabilization. The present study would help in determining dynamic parameters of peat and also suggest stabilization procedures.