Factors Influencing Pile Friction Bearing Capacity: Proposing a Novel Procedure Based on Gradient Boosted Tree Technique

In geotechnical engineering, there is a need to propose a practical, reliable and accurate way for the estimation of pile bearing capacity. A direct measure of this parameter is difficult and expensive to achieve on-site, and needs a series of machine settings. This study aims to introduce a process for selecting the most important parameters in the area of pile capacity and to propose several tree-based techniques for forecasting the pile bearing capacity, all of which are fully intelligent. In terms of the first objective, pile length, hammer drop height, pile diameter, hammer weight, and N values of the standard penetration test were selected as the most important factors for estimating pile capacity. These were then used as model inputs in different tree-based techniques, i.e., decision tree (DT), random forest (RF), and gradient boosted tree (GBT) in order to predict pile friction bearing capacity. This was implemented with the help of 130 High Strain Dynamic Load tests which were conducted in the Kepong area, Malaysia. The developed tree-based models were assessed using various statistical indices and the best performance with the lowest system error was obtained by the GBT technique. The coefficient of determination (R2) values of 0.901 and 0.816 for the train and test parts of the GBT model, respectively, showed the power and capability of this tree-based model in estimating pile friction bearing capacity. The GBT model and the input selection process proposed in this research can be introduced as a new, powerful, and practical methodology to predict pile capacity in real projects.

EXPEDIENCY OF USING FRICTION-BEARING ASBESTOS-RUBBER MATERIALS IN FRICTION UNITS

The article presents an analysis and comparison of friction elements consisting of Ferodo and retinax with asbestos-rubber friction material 143-63 and 8-45-62 in the nodes and brakes of forging and pressing machines operated at the factories of the forest and woodworking industry. In Russia, widely used friction materials Ferodo and retinax in the clutches and brakes of operating machines no longer satisfy consumers in many cases due to their low strength and wear resistance, which began to limit the performance of friction units. The analysis showed that the use of friction asbestos-rubber materials of grades 143-63 and 8-45-62 in the nodes and brakes of forging and pressing machines operated at the factories of the forest and woodworking industry, will dramatically increase both the productivity of machines and their performance, and also makes it possible to significantly reduce the cost of maintenance and repair of forging and pressing equipment.

Axial Bearing Capacity Analysis of Pile Foundation using Nakazawa Method

Pile foundation serves to distribute all the loads in the building to the ground. There are several calculation methods for bearing capacity of pile foundation, one of them is Nakazawa method. Nakazawa method adapted from calculation used in Japan where it is relevant for soft soils. The aim of this research is to obtain axial bearing capacity of pile foundation that can withstand axial forces using Nakazawa method. The parameter that used for the calculation is modified or average N-value (). The analysis result shows the value is smaller than N existing, indicate that Nakazawa tend to use weaker value of N blows. It means the calculation is considered softer type of soils than the existing ones.The value of point bearing capacity, Rp, assimilate to the pattern of N-SPT. The result value of friction bearing, Rf, in respect of depth shows the linear trending. Rf along the pile depends on the friction interaction between soil and structure. This phenomena influenced by the soil type. The value of cohession along the pile augment, means the ability of soils to stick to the pile/structure is also high. It explains why the value of friction bearing is bigger in respect of depth.