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Stability with first time or reactivated landslides depends upon the residual shear strength of soil. This paper describes prediction of the residual strength of soil based on index properties using two machine learning techniques. Different Artificial Neural Network (ANN) models and Support Vector Machine (SVM) techniques have been used. SVM aims at minimizing a bound on the generalization error of a model rather than at minimizing the error on the training data only. The ANN models along with their generalizations capabilities are presented here for comparisons. This study also highlights the capability of SVM model over ANN models for the prediction of the residual strength of soil. Based on different statistical parameters, the SVM model is found to be better than the developed ANN models. A model equation has been developed for prediction of the residual strength based on the SVM for practicing geotechnical engineers. Sensitivity analyses have been also performed to investigate the effects of different index properties on the residual strength of soil. Keywords

Use of macro recycled plastic fibres in reinforcing concrete footpaths and precast panels offers significant economic and environmental benefits over traditionally used virgin plastic fibres or steel fibre and mesh. However, wide adoption of recycled plastic fibres by the construction industries has not yet been seen due to limited data available on their durability, mechanical properties and performance in concrete. This paper reports the findings from a laboratory study on the alkaline resistance and performance of recycled polypropylene (PP) fibres in 25 MPa and 40 MPa concrete, used for footpaths and precast panels, respectively. The recycled PP fibre was found to have lower tensile strength but higher Young's modulus than those of virgin PP fibre. The recycled PP fibre was proven to have very good alkaline resistance in the concrete and other alkaline environments. The recycled PP fibre showed excellent post-cracking performance in concrete, bringing in significant ductility. In the 40 MPa concrete the effectiveness of reinforcement of PP fibres depended on their Young's modulus and tensile strength in the crack mouth opening displacement (CMOD) test. Therefore, the recycled PP fibre produced similar or slightly lower reinforcement than that of virgin PP fibre. In the 25 MPa concrete, the Young's modulus of fibres was more effective on their reinforcement than the tensile strength, thus the recycled PP fibre produced better reinforcement than that of virgin PP fibre.

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A general formulation is presented for the analysis of arching in soils as an extension of the conventional shear plane approach, in which the slip surfaces within the soil mass are considered as vertical planes. Such an assumption results in a low estimate of the design load on the yielding buried structure because of a considerable separation between the assumed vertical slip surfaces and the actual curved slip surfaces. The arching theory presented in this paper overcomes this limitation of the conventional theory by assuming inclined slip surfaces close to the actual slip surfaces. Based on this concept, an analytical expression for the vertical stress on the yielding structure is derived; a special case of this general expression reduces to the conventional expression. The variation of the vertical stress on the yielding structure with depth has been presented graphically along with a comparison with the conventional vertical shear plane approach. It is observed that the amount of arching increases with increase in the ratio of depth to width of the yielding structure as reported in the literature