Use of Energy Absorbing Breakaway Posts for W-Beam Guardrail in Frozen Soil Conditions

2015 ◽  
Author(s):  
King Mak and John Rhode ◽  
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◽  
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Keyword(s):  
Frozen Soil ◽  
Soil Conditions ◽  
Energy Absorbing

scholarly journals Evidence for enhanced infiltration of ion load during snowmelt

2010 ◽  
Vol 7 (1) ◽  
pp. 1431-1457
Author(s):  
G. Lilbæk ◽  
J. W. Pomeroy
Keyword(s):  
Soil Moisture ◽  
Infiltration Rate ◽  
Frozen Soil ◽  
Ion Concentration ◽  
Soil Conditions ◽  
Ion Concentrations ◽  
Infiltration Rates ◽  
Dry Soil ◽  
Infiltration Excess ◽  
The Impact

Abstract. Meltwater ion concentration and infiltration rate into frozen soil both decline rapidly as snowmelt progresses. Their temporal association is highly non-linear and a covariance term must be added in order to use time-averaged values of snowmelt ion concentration and infiltration rate to calculate chemical infiltration. The covariance is labelled enhanced infiltration and represents the additional ion load that infiltrates due to the timing of high meltwater concentration and infiltration rate. Previous assessment of the impact of enhanced infiltration has been theoretical; thus, experiments were carried out to examine whether enhanced infiltration can be recognized in controlled laboratory settings and to what extent its magnitude varies with soil moisture. Three experiments were carried out: dry soil conditions, unsaturated soil conditions, and saturated soil conditions. Chloride solution was added to the surface of frozen soil columns; the concentration decreased exponentially over time to simulate snow meltwater. Infiltration excess water was collected and its chloride concentration and volume determined. Ion load infiltrating the frozen soil was specified by mass conservation. Results showed that infiltrating ion load increased with decreasing soil moisture as expected; however, the impact of enhanced infiltration increased considerably with increasing soil moisture. Enhanced infiltration caused 2.5 times more ion load to infiltrate during saturated conditions than that estimated using time-averaged ion concentrations and infiltration rates alone. For unsaturated conditions, enhanced infiltration was reduced to 1.45 and for dry soils to 1.3. Reduction in infiltration excess ion load due to enhanced infiltration increased slightly (2–5%) over time, being greatest for the dry soil (45%) and least for the saturated soil (6%). The importance of timing between high ion concentrations and high infiltration rates was best illustrated in the unsaturated experiment, which showed large inter-column variation in enhanced ion infiltration due to variation in this temporal covariance.

scholarly journals Method to identify composition and production phases of spring runoff in high-latitude mid-temperate regions: a case study in the Second Songhua River Basin, China

2021 ◽  
Author(s):  
Yangzong Cidan ◽  
Hongyan Li ◽  
Wei Yang ◽  
Lin Tian
Keyword(s):  
River Basin ◽  
Hydrological Cycle ◽  
Frozen Soil ◽  
Soil Conditions ◽  
Rainfall Runoff ◽  
Songhua River ◽  
Songhua River Basin ◽  
Spring Runoff ◽  
Runoff Production ◽  
The Second Songhua River

Abstract Simulation and forecasting of runoff play an important role in the early warning and prevention of drought and flood disasters. To improve the accuracy of spring runoff simulations, it is important to identify spring runoff production patterns under the combined effect of snow and frozen soil. Based on the theory of the hydrological cycle, three important parameters, which include surface and subsurface runoff, precipitation and temperature, were selected for this study. The trend analysis, statistical analysis and Eckhardt's recursive numerical filtering method were used to qualitatively identify the production patterns of spring runoff, the start and end dates and stage periods of the production patterns. Based on the qualitative identification results, the contribution of each production runoff to the total annual runoff and the total annual spring runoff is quantitatively assessed. The results of the study show that the spring runoff production patterns in the Second Songhua River Basin can be divided into snowmelt runoff, frozen soil conditions of snowmelt–rainfall runoff and rainfall runoff under frozen soil conditions; the snowmelt production is from 21 March, the frozen soil conditions production is from 21 April and the frozen soil ablation ended on 15 June; the shortest phases of each production pattern last 28, 20 and 18 days and the longest last 31, 26 and 24 days. This research provides the basis for improving the principles of production runoff calculation in spring runoff simulation methods.

Non-iterative numerical model of soil freezing

2020 ◽  
Author(s):  
Tomas Vogel ◽  
Michal Dohnal ◽  
Jana Votrubova ◽  
Jaromir Dusek
Keyword(s):  
Heat Capacity ◽  
Phase Transitions ◽  
Energy Balance ◽  
Balance Equation ◽  
Energy Balance Equation ◽  
Frozen Soil ◽  
Soil Freezing ◽  
Soil Conditions ◽  
Apparent Heat Capacity ◽  
Soil Water Flow

<p>Increasingly, numerical models of varying complexity are used to simulate the thermal and water balance of soils exposed to freezing-thawing cycles. An important aspect of soil freezing modeling is the highly non-linear nature of the energy balance equation during phase transition. To handle the transformation between sensible and latent heat during freezing–thawing events, the majority of existing models employ the concept of apparent heat capacity. The main disadvantage of this approach is that the apparent heat capacity increases by several orders of magnitude at the freezing point, which complicates the numerical solution, possibly causing numerical oscillations and convergence problems.</p><p>An alternative approach was developed to facilitate the simulations of soil water flow and energy transport during sporadic freezing–thawing episodes, which are typical for the winter regime of humid temperate continental climate. The approach is based on an accurate non-iterative algorithm for solving highly non-linear energy balance equation during phase transitions. The suggested modeling approach abstracts from many complexities associated with the freezing phenomena in soils, yet preserves the principal physical mechanism of conserving the internal energy of the soil system during the phase transitions. When applied to simulate occasional freezing soil conditions, the model algorithm delivers the desired effect of slowing down the propagation of surface freezing temperatures into deeper soil horizons by converting water latent heat into sensible heat. The model also allows the evaluation of the extent and duration of frozen soil conditions – a crucial information for soil water flow modeling, as the frozen soil significantly reduces the soil hydraulic conductivity.</p><p>The proposed algorithm was successfully verified against analytical solutions for idealized freezing and thawing conditions and applied to both hypothetical and real field conditions.</p>

scholarly journals Experimenting and Modeling Thermal Performance of Ground Heat Exchanger Under Freezing Soil Conditions

2019 ◽  
Vol 11 (20) ◽  
pp. 5738
Author(s):  
Shuyang Tu ◽  
Xiuqin Yang ◽  
Xiang Zhou ◽  
Maohui Luo ◽  
Xu Zhang
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Soil Condition ◽  
Frozen Soil ◽  
Cold Climate ◽  
Normal Operation ◽  
Soil Conditions ◽  
Inlet Temperature ◽  
Freezing Soil ◽  
Influence Radius

Many studies have investigated the thermal performance of ground heat exchangers (GHEs) under normal conditions with inlet temperatures above 0 °C, but the freezing soil condition has been absent. We conducted a three-month test to investigate the heat transfer of GHE with inlet water-glycol temperatures of −7~0 °C. An improved thermal resistance and capacity (RC) model was developed to investigate the heat transfer between vertical single U-tube GHEs and the frozen soil. After validating with experimental results and CFD simulations, the RC model was applied to analyze GHEs’ thermal performance under different freezing soil conditions. It shows that the frozen soil increases GHE’s heat transfer capacity by 30% and the freezing inlet temperature has limited impacts on temperature distribution around the exchanger (with < 4 m influence radius). The GHEs’ heat transfer rate remained at 75~80 W/m throughout the three-month test, which is surprisingly high to ensure the normal operation of the ground source heat pump (GSHP). These findings can be references for designing and operating GSHP systems in cold and severe cold climate zones, and the RC model can be applied to analyze future GHEs performance with phase change processes.

Water Movement and Loss Under Frozen Soil Conditions

1964 ◽  
Vol 28 (5) ◽  
pp. 700-703 ◽  
Author(s):  
Hayden Ferguson ◽  
Paul L. Brown ◽  
David D. Dickey
Keyword(s):  
Water Movement ◽  
Frozen Soil ◽  
Soil Conditions

scholarly journals Response of the Meltwater Erosion to Runoff Energy Consumption on Loessal Slopes

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1522 ◽  
Author(s):  
Tian Wang ◽  
Peng Li ◽  
Jingming Hou ◽  
Zhanbin Li ◽  
Zongping Ren ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Soil Erosion ◽  
Flow Rate ◽  
Erosion Rate ◽  
Frozen Soil ◽  
Soil Conditions ◽  
Soil Slope ◽  
Flow Rates ◽  
Soil Erosion Rate ◽  
The Impact

Soil properties are influenced by freeze-thaw, which in turn influences soil erosion. Despite this, only a few studies have investigated the impacts on soil hydrodynamic processes. The objective of this study was to evaluate the impact of soil freezing conditions on runoff, its energy consumption, and soil erosion. A total of 27 laboratory-concentrated meltwater flow experiments were performed to investigate the soil erosion rate, the runoff energy consumption, and the relationship between the soil erosion rate and runoff energy consumption by concentrated flow under combinations of three flow rates (1, 2, and 4 L/min) and three soil conditions (unfrozen, shallow-thawed, and frozen). The individual and combined effects of soil condition, flow rate, and runoff energy consumption on the soil erosion rate were analyzed. For the same flow rate, the shallow-thawed and frozen slope produced mean values of 3.08 and 4.53 times the average soil erosion rates compared to the unfrozen slope, respectively. The number of rills in the unfrozen soil slope were 4, 3, and 2 under the flow rate of 1, 2, and 4 L/min, respectively. The number of rills in the thawed-shallow and frozen soil slope were all 1 under the flow rate of 1, 2, and 4 L/min. The rill displayed disconnected distribution patterns on the unfrozen slope, but a connected rill occurred on the shallow-thawed and frozen slopes. The average rill width on unfrozen, thawed-shallow, and frozen soil slopes increased by 1.87 cm, 4.38 cm, and 1.68 cm as the flow rate increased from 1 L/min to 4 L/min. There was no significant difference in the rill length on the frozen slope under different flow rates (p > 0.05). The runoff energy consumption ranged from unfrozen > shallow-thawed > frozen slopes at the same flow rate. The soil erosion rate had a linear relationship with runoff energy consumption. The spatial distribution of the runoff energy implied that soil erosion was mainly sourced from the unfrozen down slope, shallow-thawed upper slope, and frozen full slope.

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