Study on the influence mechanism and correlation model of rockfall parameters on indentation morphology
In the complex and dynamic mountainous terrains, rockfalls are a prominent and typical geological hazard. Characterized by their high - degree of suddenness, marked randomness, and wide - spread spatial distribution, rockfalls have become critical disaster - inducing factors that pose a significant...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Editorial Department of Journal of Sichuan University (Engineering Science Edition)
2025-01-01
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| Series: | 工程科学与技术 |
| Subjects: | |
| Online Access: | http://jsuese.scu.edu.cn/thesisDetails#10.12454/j.jsuese.202400891 |
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| Summary: | In the complex and dynamic mountainous terrains, rockfalls are a prominent and typical geological hazard. Characterized by their high - degree of suddenness, marked randomness, and wide - spread spatial distribution, rockfalls have become critical disaster - inducing factors that pose a significant threat to the safety of transportation infrastructure in mountainous areas. Among the various engineering measures designed to mitigate the risk of rockfalls, the shed - tunnel structure is one of the most essential countermeasures. However, in mountainous regions lacking rockfall movement monitoring data, directly obtaining key analysis parameters such as rockfall size, impact velocity, and impact angle is extremely difficult. Current design methods mainly rely on a combination of code - specified values, detailed field investigations, and complex numerical simulations. Nevertheless, this approach, which is based on regional average parameters, fails to comprehensively capture the complex rockfall movement characteristics influenced by the intricate interaction of terrain and geological conditions.Impact indentations, left by rockfalls on soil media, are silent recorders of these events. They contain crucial information about punching failure modes, contact - interface energy dissipation, and the evolution of elastoplastic deformation. In theory, the morphological analysis of these indentations can be used to quantitatively reconstruct key rockfall movement parameters. This innovative approach provides a new and promising method for the inversion analysis of rockfall disasters, potentially revolutionizing our understanding and management of such hazards.Scholars have conducted in - depth research on the resistance characteristics during the quasi - static and dynamic penetration of objects. Through a combination of low - speed impact granular medium experiments and sophisticated numerical simulation methods, they have explored the velocity field and packing density of granular media. As a result, they have revealed the correlation mechanism between local rheological characteristics and macroscopic mechanical responses. This achievement provides a solid microscopic theoretical basis for understanding the morphological evolution of impact indentations, bridging the gap between the micro - and macro - scale material behaviors.The formation and degradation mechanisms of the morphological characteristics of meteorite impact indentations have been applied in planetary science to invert the physical property parameters of the celestial body surface, such as porosity and strength. This application serves as an important calibration basis for the remote sensing interpretation of the planetary surface. In the context of rockfall disasters, existing research has made some progress. For example, it has focused on calculating the rockfall impact force and coefficient of restitution through the indentation depth and reconstructing the rockfall movement path based on the indentation position. However, the morphological characteristic mechanism of impact indentations remains largely unstudied, and a quantitative correlation model between the morphology and rockfall movement parameters has yet to be established.This paper proposes a novel method by utilizing the impact indentations left along the rockfall movement paths. The aim is to rapidly and accurately evaluate key parameters, including rockfall impact velocity, size, and movement angle. This, in turn, can assist in reconstructing the historical movement trajectory of rockfalls and assessing the potential risk range more precisely. To achieve this, a series of physical model tests of rockfall oblique impact on sand indentations were carried out. By integrating high - speed photography, laser scanning, and point - cloud automatic extraction technologies, a comprehensive analysis of the morphological evolution patterns and classification characteristics of rockfall indentations under different impact angles was conducted. Moreover, the three - dimensional parameters (length, width, depth, volume) that describe the indentation morphology were quantified, providing a numerical basis for further analysis.Based on these results, the influence mechanism of rockfall characteristic parameters (diameter, impact velocity, angle) on the indentation morphological parameters was revealed. Through rigorous mathematical analysis and theoretical deduction, a dimensionless correlation model was established, which is fundamental for understanding the complex relationship between rockfall behavior and indentation morphology.The main research results are as follows (1) The morphological evolution of indentations can be divided into three stages: transient compression, penetration deceleration, and collapse. The impact angle is a dominant factor that significantly affects the morphological asymmetry, adding complexity to the process. (2) The morphological parameters show a non - linear positive correlation with the impact energy. The sensitivity indices of length and width to the impact energy level are approximately equal (0.23 - 0.24), indicating a certain symmetry in their response to energy changes. Additionally, the influence of the impact angle on the morphological parameters is relatively independent in terms of the scaling coefficient, highlighting its unique role in shaping the indentation morphology. (3) Dimensionless analysis shows that the length - width ratio is mainly controlled by the angle factor. With 15° as the critical angle, its change trend transitions from a gentle to a rapid growth, indicating a fundamental change in the morphological characteristics. Moreover, the dimensionless depth and volume can be quantitatively related through the impact factor and the angle factor, further clarifying the underlying relationships in the system. (4) The correlation model was verified through a series of verification group experiments. The results show that the maximum error is within 20%, demonstrating the reliability and feasibility of inverting rockfall movement parameters based on in - situ impact indentations. This validates the practicality of the proposed method and paves the way for its wider application. |
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| ISSN: | 2096-3246 |