Effect of Thin Layer on Bearing Capacity in Layered Profile Soil


Abdul Farhan,Farman Ullah,Fawad Ahmad,Mehr E Munir,




Bearing capacity,plate load test,


Bearing capacity is the main criteria for designing the foundation of a structure. Several theories and experimental methods have been propounded by many researchers for computing the bearing capacity parameters separately. Traditional bearing capacity theories for determining the ultimate bearing capacity of shallow foundations assume that the bearing stratum is homogenous and infinite. However this is not true in all cases. Layered soils are mostly encountered in practice. It is possible to encounter a rigid layer at shallow depth or the soil may be layered and have different shear strength parameters. In such cases shear pattern gets distorted and bearing capacity becomes dependent on the extent of the rupture surface in weaker or stronger material. The best estimation of bearing capacity on layered soil are possible only, if the pressure-settlement characteristics of the foundation-soil are known for the size of the footing. From the review of literature, it may be noted that the bearing capacity equations proposed for the homogenous soils by Terzaghi (1943) and Meyerhof (1951) are not applicable to layered soils. Hence it is necessary to develop an equation for predicting the bearing capacity of granular layered soils. In present investigation, plate load test have been conducted in a large tank to observe the load settlement behavior of plates of different sizes resting on layered granular soils. Tests were conducted on two layers of soils. Fine gravel layer overlain sand layer were tested using mild steel plates of square shapes. The effect of the placement of layers on the bearing capacity characteristics of footing, has been studied and an equation for predicting the bearing capacity of two layered granular soils is developed based on the plate load test data.


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