scholarly journals Study on hydrodynamic characteristics and influence factors of asphalt pavement runoff

2021 ◽  
Author(s):  
Wang Xiao ◽  
Chen Hui ◽  
Ni Dong ◽  
Zhao Jing
Keyword(s):  
Surface Roughness ◽  
Asphalt Pavement ◽  
Thin Sheet ◽  
Maximum Flow ◽  
Geometric Parameters ◽  
Hydrodynamic Characteristics ◽  
Flow Depth ◽  
Slope Length ◽  
Horizontal Alignment ◽  
Longitudinal Slope

Abstract A hydrodynamic model is developed for rainfall runoff on asphalt pavement using two-dimensional shallow water equations. A simple yet precise expression is presented to compute flow velocity in order to alleviate the problems associated with numerical instabilities due to small water depths of thin sheet flow. The developed model performed well against measured data and numerical results in two segments. Then, the model is applied to study the influence of highway horizontal alignment, drainage manner, rainfall pattern, surface roughness and geometric parameters on pavement runoff. The results demonstrate that: (i) the influence of highway horizontal alignment on pavement runoff is nonsignificant, while that of drainage manner and the pavement surface roughness is significant. Great differences are observed in flow depth under concentrated drainage and overflow drainage conditions, especially in the area beyond 6 m away from the highway center axis; (ii) remarkable differences in maximum flow depth and peak runoff are presented under uneven and even rainfall conditions, while no great differences are found under three uneven rainfall conditions (front type, center front type and back front type); (iii) the sensitivity of the geometric parameters to the maximum flow depth from strong to weak is cross slope, width, slope length, and longitudinal slope under overflow drainage condition; while that is width, slope length, longitudinal slope and cross slope under concentrated drainage condition.

scholarly journals Analysis of Shear Stress and Rutting Performance of Semirigid Base Asphalt Pavement on Steep Longitudinal Slope

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jiafu Guo ◽  
Song Yang ◽  
Yongchao Sun ◽  
Zhensheng Chao ◽  
Ruikang Yang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Prediction Model ◽  
Calculation Method ◽  
Asphalt Pavement ◽  
Critical Parameters ◽  
Shear Stresses ◽  
Distribution Characteristics ◽  
Slope Length ◽  
Longitudinal Slope ◽  
Interlayer Bond

Rutting is the most common distress of the asphalt pavement with a semirigid base, mainly when located on a steep longitudinal slope. Previous studies have shown that shear stress is the leading cause of rutting. Therefore, it is essential to analyze the distribution characteristics of shear stress to evaluate pavement rutting performance. Firstly, the truck speed was measured at different locations on the steep longitudinal slope section. Then, the calculation method of shear stress was improved based on the method of “systematic clustering.” The distribution characteristics of shear stress were studied under the different gradients, slope lengths, horizontal forces, and interlayer bond conditions. Finally, the rutting prediction model was used to evaluate the rutting performance of the steep longitudinal slope section. The results show two critical parameters of a steep longitudinal slope: gradient and slope length can be quantified by establishing the relationship between truck speed and those parameters. The improved shear stress calculation method can correspond well with the layer where maximum rutting occurs. Gradients and slope lengths have little effect on shear stresses, while horizontal forces and interlayer bond conditions significantly change the shear stress distribution characteristics within the pavement. For the steep longitudinal slope sections, the rutting prediction model should consider the truck speed separately. With increasing gradient and slope length, the rutting increases the fastest in the middle layer. For sections with horizontal forces and poor interlayer bonding, the layers with the highest rutting accumulation are the upper layer and the lower layer, respectively.

scholarly journals New tsunami damage functions developed in the framework of SCHEMA project: application to European-Mediterranean coasts

2011 ◽  
Vol 11 (10) ◽  
pp. 2835-2846 ◽  
Author(s):  
N. Valencia ◽  
A. Gardi ◽  
A. Gauraz ◽  
F. Leone ◽  
R. Guillande
Keyword(s):  
Fragility Curves ◽  
Construction Material ◽  
Maximum Flow ◽  
Indian Ocean Tsunami ◽  
Cumulative Probability ◽  
Flow Depth ◽  
Damage Functions ◽  
Damage Level ◽  
Tsunami Damage ◽  
Mediterranean Areas

Abstract. In the framework of the European SCenarios for tsunami Hazard-induced Emergencies MAnagement (SCHEMA) project (www.schemaproject.org), we empirically developed new tsunami damage functions to be used for quantifying the potential tsunami damage to buildings along European-Mediterranean coasts. Since no sufficient post-tsunami observations exist in the Mediterranean areas, we based our work on data collected by several authors in Banda Aceh (Indonesia) after the 2004 Indian Ocean tsunami. Obviously, special attention has been paid in focusing on Indonesian buildings which present similarities (in structure, construction material, number of storeys) with the building typologies typical of the European-Mediterranean areas. An important part of the work consisted in analyzing, merging, and interpolating the post-disaster observations published by three independent teams in order to obtain the spatial distribution of flow depths necessary to link the flow-depth hazard parameter to the damage level observed on buildings. Then we developed fragility curves (showing the cumulative probability to have, for each flow depth, a damage level equal-to or greater-than a given threshold) and damage curves (giving the expected damage level) for different classes of buildings. It appears that damage curves based on the weighted mean damage level and the maximum flow depth are the most appropriate for producing, under GIS, expected damage maps for different tsunami scenarios.

scholarly journals ANALYSIS OF TSUNAMI SCOUR AROUND SQUARE STRUCTURES USING A PUMP-DRIVEN FLOW METHOD

2020 ◽  
pp. 8
Author(s):  
Rafael Aranguiz ◽  
Oscar Link ◽  
Jose Aliaga ◽  
Oscar Briones ◽  
Ruben Alarcon ◽  
...  
Keyword(s):  
Solitary Waves ◽  
Laboratory Experiments ◽  
Maximum Flow ◽  
Sediment Deposition ◽  
Scour Depth ◽  
Flow Depth ◽  
Field Surveys ◽  
Flow Method ◽  
Tsunami Scour ◽  
Tsunami Event

Estimation of the maximum scour depth is important for defining the size and depth of building foundations in order to avoid failure during a tsunami event (Jayaratne, et al 2016). Traditionally, tsunami scour has been studied in laboratory experiments that use solitary waves. However, it has been demonstrated that this type of wave does not represent well a real tsunami (Madsen et al, 2008). In addition, results from field surveys are based on the scour depth after the tsunami event, studying only the maximum flow depth, and ignoring other hydrodynamic features such as velocity and wave period, as well as sediment deposition. The main objective of this research is to estimate maximum tsunami scour around rectangular structures as a function of realistic tsunami variables.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/ykb-JyL7lsE

Experimental research on the deep-hole boring of pure niobium tube

2020 ◽  
Vol 234 (8) ◽  
pp. 1124-1132
Author(s):  
Xiaolan Han ◽  
Zhanfeng Liu ◽  
Yazhou Feng
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Experimental Research ◽  
Process Parameters ◽  
Cutting Tool ◽  
Geometric Parameters ◽  
Deep Hole ◽  
High Quality ◽  
Pure Niobium ◽  
Hole Axis

In the deep-hole boring process on pure niobium tube, there exist some problems including serious tool wear, tough chips, and poor surface quality. In order to bore high-quality deep holes on rolled niobium tube, the cutting tool structure and boring process parameters suitable for machining rolled niobium tube were designed and two experimental schemes were proposed. The results showed that the geometric parameters of the cutting tool and process parameters have important influences on the tool wear, chip morphologies, hole-axis deflection, and hole surface roughness. By adjusting the geometric parameters of the cutting tool and boring process parameters, reasonable geometric parameters of the cutting tool and boring process parameters were obtained.

scholarly journals A New Compression Test for Determining Free Surface Roughness Evolution in Thin Sheet Metals

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 451 ◽  
Author(s):  
Tsuyoshi Furushima ◽  
Kohei Aoto ◽  
Sergei Alexandrov
Keyword(s):  
Surface Roughness ◽  
Free Surface ◽  
Compression Test ◽  
Thin Sheet ◽  
Principal Strain ◽  
Strain Rates ◽  
Thin Sheets ◽  
Strain Paths ◽  
Effect Of The Support ◽  
Metallic Sheet

In sheet microforming processes, in-surface principal strain rates may be compressive such that the thickness of the sheet increases in the process of deformation. In general, the evolution of free surface roughness depends on the sense of the principal strain normal to the free surface. Therefore, in order to predict the evolution of free surface roughness in processes in which this normal principal strain is positive by means of empirical equations, it is necessary to carry out experiments in which the thickness of the sheet increases. Conventional experiments, such as the Marciniak test, do not provide such strain paths. In general, it is rather difficult to induce a sufficiently uniform state of strain in thin sheets of increasing thickness throughout the process of deformation because instability occurs at the very beginning of the process. The present paper proposes a compression test for thin sheets. Teflon sheets are placed between support jigs and the metallic sheet tested to prevent the occurrence of instability and significantly reduce the effect of the support jigs on the evolution of surface roughness. The test is used to determine the evolution of surface roughness in thin sheets made of C1220-O under three strain paths.

scholarly journals Impact of a 1755-like tsunami in Huelva, Spain

2010 ◽  
Vol 10 (1) ◽  
pp. 139-148 ◽  
Author(s):  
V. V. Lima ◽  
J. M. Miranda ◽  
M. A. Baptista ◽  
J. Catalão ◽  
M. Gonzalez ◽  
...  
Keyword(s):  
Source Parameters ◽  
Critical Factor ◽  
Maximum Flow ◽  
High Energy ◽  
Tsunami Source ◽  
Flow Depth ◽  
Large Area ◽  
Inundation Extent ◽  
Run Up ◽  
The Impact

Abstract. Coastal areas are highly exposed to natural hazards associated with the sea. In all cases where there is historical evidence for devastating tsunamis, as is the case of the southern coasts of the Iberian Peninsula, there is a need for quantitative hazard tsunami assessment to support spatial planning. Also, local authorities must be able to act towards the population protection in a preemptive way, to inform "what to do" and "where to go" and in an alarm, to make people aware of the incoming danger. With this in mind, we investigated the inundation extent, run-up and water depths, of a 1755-like event on the region of Huelva, located on the Spanish southwestern coast, one of the regions that was affected in the past by several high energy events, as proved by historical documents and sedimentological data. Modelling was made with a slightly modified version of the COMCOT (Cornell Multi-grid Coupled Tsunami Model) code. Sensitivity tests were performed for a single source in order to understand the relevance and influence of the source parameters in the inundation extent and the fundamental impact parameters. We show that a 1755-like event will have a dramatic impact in a large area close to Huelva inundating an area between 82 and 92 km2 and reaching maximum run-up around 5 m. In this sense our results show that small variations on the characteristics of the tsunami source are not too significant for the impact assessment. We show that the maximum flow depth and the maximum run-up increase with the average slip on the source, while the strike of the fault is not a critical factor as Huelva is significantly far away from the potential sources identified up to now. We also show that the maximum flow depth within the inundated area is very dependent on the tidal level, while maximum run-up is less affected, as a consequence of the complex morphology of the area.

Shearing Edging Investigation in High-Speed Blanking Process Applying Precision Progressive Die

2013 ◽  
Vol 668 ◽  
pp. 460-464
Author(s):  
Zhen Yuan Huang ◽  
Feng Ruan
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Orthogonal Experiment ◽  
Thin Sheet ◽  
Progressive Die ◽  
Small Complex ◽  
Thin Sheet Metal ◽  
The One ◽  
Blanking Process

The high-speed blanking process applying precision progressive die represents the one of the highest level of today’s stamping technology, mainly is used for the production of the ultra-thin, small, complex electronic components. An orthogonal experiment scheme with three factors (including blanking clearance, surface roughness of the die, stamping speed) was established in this paper based on the actual production. The high-speed blanking process experiment applying precision progressive die was carried out base on this scheme. The quality of the shearing edging of blanking parts was used to evaluate the different influence degree of three factors. The result showed that the surface roughness of the die affected the quality of the shearing edging more than that of the other two. The higher the die surface accuracy, the better the quality of the shearing edging. The result also showed that the high speed can reduce the quantity of the burr of the blanking of the ultra-thin sheet metal.

scholarly journals Creation of Prompt and Thin-Sheet Splashing by Varying Surface Roughness or Increasing Air Pressure

2012 ◽  
Vol 109 (5) ◽  
Author(s):  
Andrzej Latka ◽  
Ariana Strandburg-Peshkin ◽  
Michelle M. Driscoll ◽  
Cacey S. Stevens ◽  
Sidney R. Nagel
Keyword(s):  
Surface Roughness ◽  
Thin Sheet ◽  
Air Pressure

scholarly journals Experimental-Numerical Study of Indexation of Scenic Road Vertical Alignment in China

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ronghua Wang ◽  
Xingliang Liu ◽  
Zhe Yuan
Keyword(s):  
Field Experiments ◽  
Numerical Study ◽  
Design Method ◽  
Maximum Velocity ◽  
Vertical Alignment ◽  
Slope Length ◽  
Rapid Variation ◽  
Forest Park ◽  
Longitudinal Slope ◽  
Relative Errors

The vertical alignment design method of road in scenic spots does not evolve enough along the vehicle’s rapid variation. Values of the maximum longitudinal slope (MLS) and longest slope length (LSL) applicable to scenic roads used by the environmental-friendly vehicle (EFV) are not provided. To compensate for this shortage, a multibody vehicle dynamic model in uphill traving is built, providing the static equilibrium state and dynamic balancing process of a typical vehicle. MLS and LSL values in scenic roads are obtained based on this model through numerical simulation, considering typical EFV, maximum velocity loss (MVL), and ideal velocity loss (IVL). Field experiments for verifying the results are also carried out in Huashan Mountain, Cuihua Mountain National Park, and Taiping Forest Park, using two EFV types. MLS and LSL values in scenic roads applicable to EFV obtained in this research vary from 7.8% to 10.2% and 200 to 955 m, respectively, and both are larger than the corresponding values in current criteria. According to verification results, relative errors of climbing velocity vary from 0.0104 to 0.0205, showing the dynamic model’s accuracy and further proving the practicality of MLS and LSL values obtained. The results obtained in this research lay a foundation for establishing the scenic-road vertical alignment design method.

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