Model and Prototype Testing of Well Rings as Foundation for Residential Buildings

Growing human population has caused the increase in the tempo of construction activity world wide.Since new techniques are either available or constantly emerging the sites which have been deemed unsuitable are being put to use for the construction of new and challenging structures. The foundations for the residential buildings in paddy fields and marshy land with water table near the ground level are constructed in the dense or medium dense sand layers found at shallow depth. The commonly used fill materials are sea sand, river sand gravel or plain cement concrete. Although this method is practiced greatly in rural areas, fewer load tests have been conducted to study its effectiveness especially in the case of residential buildings. In this present study, an attempt has been made to study the effectiveness of using lateral confinement to improve the ultimate bearing capacity of shallow foundation. Model of confined footing using a FEM package, PLAXIS was developed and analysed and compared to the experimental results obtained from plate load test with different number of well rings. The objective is to study the effectiveness of well rings in improving the load carrying capacity of loose sand beds. The model developed is in good agreement to the prototype. Load carrying capacity is found to increase initially up to two wells and then decrease when the number of well is three.