Bearing Capacity Zonation of Urban Areas of Dhulikhel and Banepa for Shallow Foundation

Abstract

The stability of every structure depends upon the stability of the supporting soil. Properties of soil and its bearing capacity is the major factor in selection of type of foundation. The soil beneath the structure should sustain the loads without causing shear failure and also with tolerable resulting settlement to be safe from structural damage.

Construction of residential and commercial buildings in Banepa and Dhulikhel are being increased continuously without evaluating bearing capacity of the particular zone. The target of this study is to prepare the Bearing capacity zonation map of urban areas around Araniko Highway periphery of Dhulikhel and Banepa. This map will be useful for the municipalities for preliminary design of foundation, feasibility study, planning of detail investigations. To prepare this, bore log secondary data (SPT-N) and available soil parameters from various seventy-two locations are taken. Terzaghi (1943), Meyerhof (1963), Hansen (1970) and Vesic (1973) approaches have been used to evaluate Bearing capacity from Shear Failure Criteria whereas Meyerhof (1965) and Bowels (1987) approaches from Settlement Criteria. Least value for BC is taken and plotted in map using GIS. The BC have been further calculated from Plaxis 2D. The verification is done from laboratory tests. The parameters of soil that should be well-thought-out in Plaxis models and theoretical approaches are Cohesion, Angle of Internal Friction, unit weight, Poisson’s ratio and modulus of elasticity for each 1.5 m and 3m depth. Plaxis is used to create numerical model. The soil is presented as 2D soil model and drained behavior with axisymmetrical model are being taken into attention. Finite Element Analysis is executed using Mohr-Coulomb failure criteria. Load is applied on Foundation, till the failure takes place in the soil. The Bearing capacity shall be obtained from Load Displacement curve. The research shows that Allowable Bearing capacity of Dhulikhel ranges from 83 kPa at Dhulikhel-3 (85.547190E, 27.631433N) to 447 kPa at Dhulikhel-9 (85.564935E, 27.599648N) and Banepa ranges from 134 kPa at Banepa- 10 (85.505769 E, 27.641141 N) to 439 kPa at Banepa-11 (85.516919 E, 27.623785 N) for shallow foundation with square footing of width 1.5m.