Comparisons of Static and Dynamic Analyses on Toppling Behaviors of Pile Driving Machinery, etc., on Soft Foundation

Abstract

Toppling accidents of heavy machinery such as pile drivers, cranes, high-altitude work vehicles, and jacks have been recurring in the world. In the past, researches focused to find the overturning moment which causes toppling. However, it is believed that the toppling accidents are related to structural stability issues, in which cases the accidents could possibly occur without any overturning moment. Accidents involving the structural instability are difficult to predict as the directions of load and deformation are different. This unpredictability is considered as a fundamental contributing factor to accidents recurring. Theoretical studies by static and dynamic analyses have been performed by the authors. It was found that not only static deformations but also dynamic inertial forces influence the increased risk of toppling. In the cases of structural instability, dynamic inertial force might amplify angular displacement beyond the critical stability angle, leading to rapid toppling and often resulting in significant disasters. Factors leading to toppling as a trigger include unexpected movement onto weak ground, increased magnitude of load and height, and greater ground incline. Taking those factors into consideration, this paper attempts to elucidate the mechanism of pile drivers' toppling by comparing static and dynamic analyses and providing essential information for preventing accidents. From both static and dynamic analyses, toppling behavior will be described in the load-deformation and the support stiffness-deformation relations. Furthermore, a role of temporal element is illustrated as a quick movement of the machines results in increased risk of toppling.

Received: 29 August 2023 | Revised: 8 October 2023 | Accepted: 17 October 2023

Conflicts of Interest

The authors declare that they have no conflicts of interest to this work.

Data Availability Statement

The data that supports the findings of this study is openly available with toma@hgu.jp, and would be shared upon request via email.