Formation and estimation of peak impact force on suspended pipelines due to submarine debris flow

Drainage channel with step-pool systems are widely used to control debris flow. However, the blocking of debris flow often gives rise to local damage at the steps and baffles. Hence, the estimation of impact force of debris flow is crucial for design step-pools channel. This paper presents a numerical study on the impact behavior of debris flows using SPH (Smoothed Particle Hydrodynamics) method. Some important parameters, such as the baffle shape (square, triangle, and trapezoid) and the densities of debris flows are considered to examine their influence on the impact force. The results show that the largest peak impact force is obtained at the second last baffle, rather than the first baffle. Moreover, the square baffle gives rise to the largest impact force whereas the triangle baffle bears the smallest one among the three baffles. Generally, the peak impact force increases with increasing the inflow density. However, a threshold density, beyond which the peak impact force will decrease, is suggested by the simulations. Based on the numerical results, an improved expression to predict the impact force considering the inclined angle of baffle is proposed.

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The Effects of Upstream Flexible Barrier on the Debris Flow Entrainment and Impact Dynamics on a Terminal Barrier

Canadian Geotechnical Journal ◽

10.1139/cgj-2021-0119 ◽

2021 ◽

Author(s):

Hervé Vicari ◽

C.W.W. Ng ◽

Steinar Nordal ◽

Vikas Thakur ◽

W.A. Roanga K. De Silva ◽

...

Keyword(s):

Debris Flow ◽

Debris Flows ◽

Impact Force ◽

Dynamic Pressure ◽

Pressure Coefficient ◽

Flexible Barrier ◽

Impact Forces ◽

Flexible Barriers ◽

The Impact ◽

Bed Entrainment

The destructive nature of debris flows is mainly caused by flow bulking from entrainment of an erodible channel bed. To arrest these flows, multiple flexible barriers are commonly installed along the predicted flow path. Despite the importance of an erodible bed, its effects are generally ignored when designing barriers. In this study, three unique experiments were carried out in a 28 m-long flume to investigate the impact of a debris flow on both single and dual flexible barriers installed in a channel with a 6 m-long erodible soil bed. Initial debris volumes of 2.5 m3 and 6 m3 were modelled. For the test setting adopted, a small upstream flexible barrier before the erodible bed separates the flow into several surges via overflow. The smaller surges reduce bed entrainment by 70% and impact force on the terminal barrier by 94% compared to the case without an upstream flexible barrier. However, debris overflowing the deformed flexible upstream barrier induces a centrifugal force that results in a dynamic pressure coefficient that is up to 2.2 times higher than those recommended in guidelines. This suggests that although compact upstream flexible barriers can be effective for controlling bed entrainment, they should be carefully designed to withstand higher impact forces.

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Experimental Study of the Debris Flow Slurry Impact and Distribution

Shock and Vibration ◽

10.1155/2018/5460362 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Haixin Zhao ◽

Lingkan Yao ◽

Yong You ◽

Baoliang Wang ◽

Cong Zhang

Keyword(s):

Debris Flow ◽

Debris Flows ◽

Impact Force ◽

Influence Factors ◽

Flume Experiment ◽

Middle Point ◽

Laboratory Flume ◽

Critical Issues ◽

Maximum Impact Force ◽

The Impact

In this study, we present a new method to calculate debris flow slurry impact and its distribution, which are critical issues for designing countermeasures against debris flows. There is no unified formula at present, and we usually design preventive engineering according to the uniform distribution of the maximum impact force. For conducting a laboratory flume experiment, we arrange sensors at different positions on a dam and analyze the differences on debris flow slurry impact against various densities, channel slopes, and dam front angles. Results show that the force of debris flow on the dam distributes unevenly, and that the impact force is large in the middle and decreases gradually to the both sides. We systematically analyze the influence factors for the calculation of the maximum impact force in the middle point and give the quantitative law of decay from the middle to the sides. We propose a method to calculate the distribution of the debris flow impact force on the whole section and provide a case to illustrate this method.

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An experimental evaluation of impact force on a fiber Bragg grating-based device for debris flow warning

Landslides ◽

10.1007/s10346-018-1083-0 ◽

2018 ◽

Vol 16 (1) ◽

pp. 65-73 ◽

Cited By ~ 2

Author(s):

Shaojie Zhang ◽

Changxue Xu ◽

Jiang Chen ◽

Jun Jiang

Keyword(s):

Debris Flow ◽

Fiber Bragg Grating ◽

Experimental Evaluation ◽

Impact Force ◽

Bragg Grating

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Preliminary study of debris flow impact force on a circular pillar

Physical Modelling in Geotechnics ◽

10.1201/9780429438646-53 ◽

2018 ◽

pp. 1105-1110

Author(s):

A.L. Yifru ◽

R.N. Pradhan ◽

S. Nordal ◽

V. Thakur

Keyword(s):

Debris Flow ◽

Impact Force ◽

Preliminary Study

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Analysis of a debris flow after Wenchuan Earthquake and discussion on preventive measures

Thermal Science ◽

10.2298/tsci180811224z ◽

2019 ◽

Vol 23 (3 Part A) ◽

pp. 1563-1570

Author(s):

Zhi-Long Zhang ◽

Jing Xie ◽

De-Ke Yu ◽

Zhi-Jie Wen

Keyword(s):

Debris Flow ◽

Wenchuan Earthquake ◽

Preventive Measures ◽

Impact Force ◽

Site Investigation ◽

The Wenchuan Earthquake ◽

Formation Conditions ◽

National Road ◽

And Control ◽

Debris Flow Disaster

This paper addresses a debris flow disaster in Yingxiu town after the Wenchuan earthquake. Through site investigation and data review, the geography and geological environment of the basin and the development, formation conditions and activity characteristics of the debris flow in the basin are analyzed. Calculate and analyze the characteristics of the debris flow, such as gravity, flow velocity and impact force. According to the management idea of combination of blocking and discharging, this paper proposes to arrange three blocking dams in the main ditch, construct drainage gullies in the downstream accumulation section, and prevent and control the aqueduct in the intersection of the main ditch and the G213 national road, which will be similar to the earthquake in the future. It is provided as a reference for research and prevention of the debris flow.

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NUMERICAL STUDY OF IMPACT FORCE CHARACTERISTICS OF DEBRIS FLOW

Journal of computational fluids engineering ◽

10.6112/kscfe.2020.25.4.034 ◽

2020 ◽

Vol 25 (4) ◽

pp. 34-42

Author(s):

S.G. Lee ◽

S. Lee ◽

J.Y. Lee ◽

J.A. Um ◽

W.H. Yi

Keyword(s):

Debris Flow ◽

Impact Force ◽

Numerical Study ◽

Force Characteristics

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Evaluation on anti-collision performance of multi-level bumper type anti-collision device

IABSE Congress, New York, New York 2019: The Evolving Metropolis ◽

10.2749/newyork.2019.0432 ◽

2019 ◽

Author(s):

Haoxin Guo ◽

Junjie Wang ◽

Chengdong Liu

Keyword(s):

Impact Force ◽

Superior Performance ◽

Corrosion Resistant Steel ◽

Resistant Steel ◽

Oblique Collision ◽

Corrosion Resistant ◽

Multi Level ◽

Ship Collision ◽

Energy Absorbing ◽

Peak Impact Force

An innovative Multi-level bumper and energy-consuming system (MBES) with corrosion-resistant steel floating caisson is proposed as protective structures for bridge piers against ship collision in this paper. MBES is provided with a three-level anti-collision module which consists of a corrugated-type energy-absorbing base, rubber fender, corrosion-resistant steel box filled with pre-compressed rubber tire. MBES is assembled in segments, exhibiting good energy absorbing and highly designable properties. This paper aims to evaluate the effectiveness of MBES adopted in a continuous beam bridge using finite element models. Based on the numerical model, the oblique collision situation at different positions were studied. Numerical results indicate the obvious advantages of the device by comparing peak impact force and impact duration. Significantly decrement of the peak impact force and effectively prolonged impact process indicate the superior performance of the device. Multi-level anti-collision fortification, the modular fabrication and replacement, simple maintenance, strong self-floating ability and excellent corrosion resistance make MBES very effective as a bridge protection structure in ship collision.

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Quantification of debris flow vulnerability of typical bridge substructure based on impact force simulation

Geomatics Natural Hazards and Risk ◽

10.1080/19475705.2019.1641564 ◽

2019 ◽

Vol 10 (1) ◽

pp. 1839-1862 ◽

Cited By ~ 1

Author(s):

Yuzhao Liang ◽

Feng Xiong

Keyword(s):

Debris Flow ◽

Impact Force

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Dynamic Response and Shear Demand of Reinforced Concrete Beams Subjected to Impact Loading

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455419500913 ◽

2019 ◽

Vol 19 (08) ◽

pp. 1950091 ◽

Cited By ~ 2

Author(s):

Wuchao Zhao ◽

Jiang Qian

Keyword(s):

Dynamic Response ◽

Impact Loading ◽

Parametric Study ◽

Shear Failure ◽

Impact Force ◽

Rc Beams ◽

Local Response ◽

Shear Demand ◽

The Impact ◽

Peak Impact Force

Reinforced concrete (RC) beams under the impact loading are typically prone to suffer shear failure in the local response phase. In order to enhance the understanding of the mechanical behavior of the RC beams, their dynamic response and shear demand are numerically investigated in this paper. A 3D finite-element model is developed and validated against the experimental data available in the literature. Taking advantage of the above calibrated numerical model, an intensive parametric study is performed to identify the effect of different factors including the impact velocity, impact mass and beam span-to-depth ratio on the impact response of the RC beams. It is found that, due to the inertial effect, a linear relationship exists between the maximum reverse support force and the peak impact force, while negative bending moments also appear in the shear span. In addition, the local response of the RC beams can be divided into a first impact stage and a separation stage. A shear plug is likely to be formed near the impact point at the first impact stage and a shear failure may be triggered near the support by large support forces. Based on the simulation results, simplified methods are proposed for predicting the shear demand for the two failure modes, whereas physical models are also established to illustrate the resistance mechanism of the RC beams at the peak impact force. By comparing with the results of the parametric study, it is concluded that the shear demand of the RC beams under the impact loading can be predicted by the proposed empirical formulas with reasonable accuracy.

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