scholarly journals ANALYSIS OF BEHAVIOR OF A CYLINDRICAL-SHAPE CANTILEVER EARTH RETAINING STRUCTURE, AS AFFECTED BY WALL TEMPERATURE VARIATIONS : Part 2 Stress interaction between reinforcing bars in RC earth retaining wall and those in the underground structure wall

2005 ◽  
Vol 70 (596) ◽  
pp. 41-48
Author(s):  
Satoru KAZAMA ◽  
Toshio KUMAGAI
Keyword(s):  
Wall Temperature ◽  
Retaining Wall ◽  
Underground Structure ◽  
Cylindrical Shape ◽  
Reinforcing Bars ◽  
Temperature Variations ◽  
Retaining Structure

Circumferential wall temperature variations in horizontal boiler tubes

1983 ◽  
Vol 9 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Avram Bar-Cohen ◽  
Zvi Ruder ◽  
Peter Griffith
Keyword(s):  
Wall Temperature ◽  
Temperature Variations ◽  
Boiler Tubes

The Construction Technology of Light Masonry Retaining Structure Used in Fluctuating Belt of the Three Gorges Reservoir Area

2011 ◽  
Vol 255-260 ◽  
pp. 602-606
Author(s):  
Long Fei Cheng ◽  
Lin Yan Li
Keyword(s):  
Precast Concrete ◽  
Retaining Wall ◽  
Coarse Grained ◽  
Three Gorges Reservoir Area ◽  
Construction Technology ◽  
Reservoir Area ◽  
Retaining Structure ◽  
Concrete Blocks ◽  
Coarse Grained Soil

Masonry retaining structure consists of precast concrete blocks, which has good looks and is in harmony with environment. Blocks with proper shape can be used in fluctuating belt of the reservoir area. The construction of masonry structure should conform to the following steps: first, excavate the foundation ditch, lay a cushion and arrange the controlling points, insuring the quality of the first layer of blocks; it would be better to choose inorganic coarse-grained soil as filler and to set a water filtering layer with a height more than 30cm behind the retaining wall; carry on the construction of earth filling behind the wall after the blocks are fixed as requested, and then fix the geotechnical grille when the height of earth filling reaches the elevation of the grille; put Geotechnical Fabric between permeable aggregate and the earth filling behind it to keep the two materials from mixing.

scholarly journals Technical Note: Formation of airborne ice crystals in a wall independent reactor (WIR) under atmospheric conditions

2008 ◽  
Vol 8 (4) ◽  
pp. 13017-13042
Author(s):  
E. Fries ◽  
W. Haunold ◽  
E. Starokozhev ◽  
K. Palitzsch ◽  
R. Sitals ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Flow Rate ◽  
Wall Temperature ◽  
Lead Time ◽  
Aerosol Particles ◽  
Ice Crystals ◽  
Ice Formation ◽  
Atmospheric Conditions ◽  
Ice Crystal ◽  
Temperature Variations

Abstract. Both, gas and particle scavenging contribute to the transport of organic compounds by ice crystals in the troposphere. To simulate these processes an experimental setup was developed to form airborne ice crystals under atmospheric conditions. Experiments were performed in a wall independent reactor (WIR) installed in a walk-in cold chamber maintained constantly at −20°C. Aerosol particles were added to the carrier gas of ambient air by an aerosol generator to allow heterogeneous ice formation. Temperature variations and hydrodynamic conditions of the WIR were investigated to determine the conditions for ice crystal formation and crystal growth by vapour deposition. In detail, the dependence of temperature variations from flow rate and temperature of the physical wall as well as temperature variations with an increasing reactor depth were studied. The conditions to provide a stable aerosol concentration in the carrier gas flow were also studied. The temperature distribution inside the reactor was strongly dependent on flow rate and physical wall temperature. At an inlet temperature of −20°C, a flow rate of 30 L•min−1 and a physical wall temperature of +5°C turned out to provide ideal conditions for ice formation. At these conditions a sharp and stable laminar down draft "jet stream" of cold air in the centre of the reactor was produced. Temperatures measured at the chamber outlet were kept well below the freezing point in the whole reactor depth of 1.0 m. Thus, melting did not affect ice formation and crystal growth. The maximum residence time for airborne ice crystals was calculated to at 40 s. Ice crystal growth rates increased also with increasing reactor depth. The maximum ice crystal growth rate was calculated at 2.82 mg• s−1. Further, the removal efficiency of the cleaning device for aerosol particles was 99.8% after 10 min. A reliable particle supply was attained after a preliminary lead time of 15 min. Thus, the minimum lead time was determined at 25 min. Several test runs revealed that the WIR is suitable to perform experiments with airborne ice crystals.

scholarly journals Mathematical modeling of groundwaters pressure distribution in the underground structures by cylindrical form zone

2018 ◽  
Vol 196 ◽  
pp. 02025 ◽  
Author(s):  
Valeriy Telichenko ◽  
Vladimir Rimshin ◽  
Vladimir Eremeev ◽  
Vladimir Kurbatov
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Pressure Distribution ◽  
Underground Structure ◽  
Viscosity Coefficient ◽  
Soil Porosity ◽  
Cylindrical Shape ◽  
Underground Structures ◽  
Cylindrical Form ◽  
Analytical Formulas

A mathematical model is developed for studying the distribution of groundwater pressure and its variation in the zone of underground structures of a cylindrical shape. Based on the created model, the influence of the thickness of the aquifer, the soil porosity, the filtration coefficient, the viscosity coefficient and the piezoelectric conductivity coefficient on the pressure that groundwater exerts on the lower part of the underground structure is investigated. The analysis of the possibility of pushing the structure and breaking the foundation under the influence of pressure caused by groundwater is analyzed. Analytical formulas are obtained for estimating the stresses in the foundation and predicting the possibility of its destruction.

scholarly journals Active Earth Pressure of Limited C-φ Soil Based on Improved Soil Arching Effect

2020 ◽  
Vol 10 (9) ◽  
pp. 3243
Author(s):  
Meilin Liu ◽  
Xiangsheng Chen ◽  
Zhenzhong Hu ◽  
Shuya Liu
Keyword(s):  
Retaining Wall ◽  
Pressure Coefficient ◽  
Ground Surface ◽  
Side Wall ◽  
Earth Pressure ◽  
Active Earth Pressure ◽  
Soil Arching ◽  
Retaining Structure ◽  
Arching Effect ◽  
Soil Arching Effect

For c-φ soil formation (cohesive soil) of limited width with ground surface overload behind a deep retaining structure, a modified active earth pressure calculation model is established in this study. And three key issues are addressed through improved soil arching effect. First, the soil-wall interaction mechanism is determined by considering the soil arching effect. The slip surface of a limited soil is proved to be a double-fold line passing through the retaining wall toe and intersecting the side wall of the existing underground structure until it reaches the ground surface along the existing side wall. Second, the limited width boundary is explicated. And third, the variation in the active earth pressure from parameters of limited c-φ soil is determined. The lateral active earth pressure coefficient is nonlinear distributed based on the improved soil arching effect of the symmetric catenary curve. Furthermore, the active earth pressure distribution, the tension crack at the top of the retaining wall and the resultant force and its action point were obtained. By comparing with the existing analytical methods, such as the Rankine method, it demonstrates that the model proposed in this study is much closer to the measured and numerical results. Ignoring the influence of soil cohesion and the limited width will exponentially reduce the overall stability of the retaining structure and increase the risk of accidents.

Earth Pressure Analysis and Retaining Walls

2015 ◽  
pp. 313-410
Keyword(s):  
Retaining Wall ◽  
Earth Pressure ◽  
Retaining Walls ◽  
Wall Friction ◽  
Underground Structures ◽  
Retaining Structure ◽  
Earth Pressures ◽  
Braced Excavations ◽  
Surcharge Load ◽  
Line Loads

Retaining walls are structures used not only to retain earth but also water and other materials such as coal, ore, etc. where conditions do not permit the mass to assume its natural slope. In this chapter, after considering the types of retaining wall, earth pressure theories are developed in estimating the lateral pressure exerted by the soil on a retaining structure for at-rest, active, and passive cases. The effect of sloping backfill, wall friction, surcharge load, point loads, line loads, and strip loads are analyzed. Karl Culmann's graphical method can be used for determining both active and passive earth pressures. The analysis of braced excavations, sheet piles, and anchored sheet pile walls are considered and practical considerations in the design of retaining walls are treated. They include saturated backfill, wall friction, stability both external and internal, bearing capacity, and proportioning the dimensions of the retaining wall. Finally, a brief treatment of earth pressure on underground structures is included.

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