Ultimate end bearing capacity of rock-socketed pile based on generalized nonlinear unified strength criterion

In order to study the mechanism of bearing behavior at the tip of a pile embedded in rock, the generalized nonlinear unified strength criterion and slip line principle for resolving the differential equation systems which govern the stress field were applied to derive the ultimate end beating capacity based on some reasonable hypothesis and failure plane model. Both numerical simulation and test results were compared with the theoretic solution. The results show good consistency with each other and verify the validity of the present approach. The depth effect with respective to embedment ratio and other influence factors like geological strength index, intermediate principal stress, overburden factor, and damage on end bearing capacity were discussed in the analytical solution. The results show that the proposed yield criterion can be much better for investigating the ultimate end bearing performance of rock-socketed pile. The end bearing capacity increases with embedment ratio and the increasing degree is influenced intensely by the above parameters. Furthermore, ignoring intermediate stress effect would underestimate the strength properties of the rock material and lead to a very conservative estimation value.

Bearing Capacity of Embedded Strip Footing on Geogrid-Reinforced Fly Ash

Fly ash is a pozzolanic waste from the burning of coal ash in thermal power plant which will be unchangeable in India and increasing environmental pollution. There is an urgent need of increasing bulk utilization of fly ash in geotechnical application. In this regard, a study was undertaken to investigate the bearing capacity of fly ash slopes (β) with the strip footing of width (B) 0.1 m located at different edge distances (De = 1B, 2B, 3B) from slope crest. These tests were conducted in the laboratory and the pressure-settlement behaviour of strip footing on unreinforced and reinforced fly ash slope having an angle of 45? was studied. The embedment ratio (Z/B = 0.30), and the depth of first layer of polyester geogrid reinforcement were investigated with different footing edge distances (De = 1B, 2B, 3B). From the experiment, pressure and settlements were measured and subsequently, the pressure settlement curves were drawn. It is observed from test results that the load carrying capacity is found to increase with an edge distance in both cases: unreinforced and reinforced slope. Also, a substantial increase is observed in the bearing capacity with the addition of geogrid reinforcement. It is observed that, the bearing capacity ratio (BCR) decreases with edge distance increase. These investigations demonstrate that both, the ultimate bearing capacity and settlement characteristics of the foundation, can be improved due to the inclusion of reinforcements within the fill.