Soil Arching over Deeply Buried Thermoplastic Pipe

2003 ◽  
Vol 1849 (1) ◽  
pp. 109-123 ◽  
Author(s):  
Shad M. Sargand ◽  
Teruhisa Masada
Keyword(s):  
Strain Gauge ◽  
Bending Stiffness ◽  
Field Soil ◽  
Stiffness Parameter ◽  
Soil Pressure ◽  
Buried Pipe ◽  
Soil Arching ◽  
Pressure Cell

Soil arching associated with buried thermoplastic pipe is discussed. First, the soil arching phenomenon is described. Then two different approaches are mentioned from the literature to represent the degree of soil arching (or vertical arching factor). The elastic solutions of Burns and Richard are revisited to derive expressions for the vertical soil arching factor for buried pipe. Comparison of the elastic solutions and field soil pressure cell readings reveals the importance of incorporating a bending stiffness parameter. With this finding, the AASHTO method for calculating the load on buried pipe is evaluated against the elastic solutions. The analysis reveals that the AASHTO method is conservative, overestimating the load on thermoplastic pipe by up to 30%. Further evidence to support the finding is found within the strain gauge readings taken on the pipe walls in the field. Therefore, alternative equations derived directly from the elastic solutions are recommended to predict the load on buried thermoplastic pipe instead of the AASHTO method.

Analysis the Influence of the Thermal Diffusivity of the Soil around Buried Pipe on Soil Physical Property

2013 ◽  
Vol 805-806 ◽  
pp. 552-556
Author(s):  
Ying Xu ◽  
Xiao Yan Liu
Keyword(s):  
Temperature Field ◽  
Thermal Diffusivity ◽  
Soil Temperature ◽  
Temperature Drop ◽  
Physical Property ◽  
Field Soil ◽  
Buried Pipeline ◽  
Buried Pipe ◽  
Soil Physical Property ◽  
Natural Temperature

In chilliness area, the temperature drop of oil in buried pipeline is affected by soil temperature field, and the thermal diffusivity is one of the main of physical property the soil, which affects the temperature drop of oil directly. This paper introduced the test principle of the thermal diffusivity of soil, and researched the influence of thermal diffusivity of soil on the soil physical property, such as soil natural temperature field, soil frozen days, depth of freezing and temperature delay, which can offer theory support for the calculation of hot oil temperature drop in buried pipeline.

Study on Load-Bearing Mechanism of Stabilizing Pile-Groups by FEM and its Application

2014 ◽  
Vol 638-640 ◽  
pp. 656-670
Author(s):  
Huan Feng Qiu ◽  
Shao Jun Fu
Keyword(s):  
Computer Code ◽  
Soil Mass ◽  
Design Parameters ◽  
Pile Groups ◽  
Soil Pressure ◽  
Soil Arching ◽  
Fine Grained ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Pile Diameter

The behaviour of pile-groups subjected to lateral soil pressure is a key consideration in establishing the design parameters of pile-groups. In this paper, one representative section of the Chongqing Jiangdong slope is taken as an example. The existence of an arching zone around pile groups for granular and fine-grained soils is first examined using the finite element computer code CORE-3D. Pile load-displacement curves and the arching effect are considered together to explain how the stresses are transferred from the soil to the piles. The key parameters controlling the soil arching effect are centre-to-centre pile spacing (S), thickness of stable soil mass (H), depth (L) of pile embedment, pile diameter (D) and these were studied extensively. An empirical equation summarising the results is presented and the results have been adopted by the designer in practice.

Buckling of a Rectangular Frame Revisited

1987 ◽  
Vol 54 (3) ◽  
pp. 617-622
Author(s):  
P. Seide
Keyword(s):  
Limit Load ◽  
Bending Stiffness ◽  
Stiffness Ratio ◽  
Stiffness Parameter ◽  
Rotational Stiffness ◽  
Height Ratio ◽  
Rectangular Frame ◽  
Uniform Beam ◽  
Symmetrical Deformation ◽  
Deformation Limit

An investigation of the buckling under uniform beam load of a rectangular frame with columns restrained by linear rotational springs indicates that for certain ranges of bending stiffness ratio, length-height ratio, and support rotational stiffness parameter, the antisymmetrical bifurcation mode of buckling does not exist and buckling occurs at a symmetrical deformation limit load. The ranges of parameters for which this phenomenon may be important are studied.

scholarly journals The influence of temperature on earth pressure cell readings

2004 ◽  
Vol 41 (3) ◽  
pp. 551-559 ◽  
Author(s):  
Lyne Daigle ◽  
Jack Q Zhao
Keyword(s):  
Temperature Effect ◽  
Applied Pressure ◽  
Earth Pressure ◽  
Temperature Calibration ◽  
Soil Pressure ◽  
Buried Structures ◽  
Pressure Cell ◽  
Linear Correction ◽  
Influence Of Temperature On ◽  
Measure Soil Pressure

Vibrating-wire earth pressure cells are often used to measure soil pressure in fills and embankments or contact pressure between soil and buried structures. Instrumentation companies provide each cell with a formula to calculate pressure based on frequency and temperature readings. This paper presents the calibration work that was carried out on a series of 76 mm diameter cells and four 228 mm diameter cells with temperatures ranging from –10 to +30 °C with and without the effect of applied pressure. Based on this work and additional data from two field sites, it was found that temperature calibration factors given on the calibration sheet specific to each cell largely underestimated the temperature effect. It was also found that the correction factors were dependent not only on temperature, but also on the pressure applied to the cell. The temperature calibration factor, which is given as a linear correction on the calibration datasheet, becomes parabolic as a pressure is applied on the cell. Based on the findings, recommendations are provided for minimizing the temperature effect on pressure cell readings and improving the accuracy of the temperature calibration factor.Key words: earth pressure cells, soil pressure, temperature calibration, instrumentation.

scholarly journals Comparison of Soil Pressure Calculating Methods Based on Terzaghi Model in Different Standards

2016 ◽  
Vol 10 (1) ◽  
pp. 481-488
Author(s):  
Lianfen Shao ◽  
Xin Zhou ◽  
Hongbiao Zeng
Keyword(s):  
Clay Soil ◽  
Friction Angle ◽  
National Standard ◽  
Cohesion Strength ◽  
European Standard ◽  
Soil Pressure ◽  
Soil Arching ◽  
Sand Soil ◽  
Pressure Calculation ◽  
Calculation Results

Soil pressure calculation method for Trenchless pipe based on the Terzaghi Soil Arching Theory have been defined in Chinese national standard GB50332-2002, North America standard ASTM F1962-09 and European standard BS EN 1594-2009. At present, the calculation results from all of the three standards have shown discrepancies with the measured soil pressure. There is little research on the issue of discrepancies in each standard based on the same Terzaghi soil arching theory. The comparison has been made to investigate the differences among all the three standards. The conclusions can be made that the calculation in both GB50332 and ASTM F1962 ignores the cohesion and compressibility of the soil, using the same method to calculate sand soil and clay soil, and does not fully consider the effect of the internal friction angle of soils, which lead to a small impact of the soil properties on the arching factor. The BS EN 1594 standard considers the cohesion strength of soils and uses two different methods for pressure of sand soil and clay soil, respectively; The comparisons show that the cohesion strength has a significant impact on soil pressure, and that the former two standards showed a higher soil pressure than BS EN 1594 since both of them ignored the cohesion strength of soils.

scholarly journals SOIL ARCHING AND LOAD TRANSFER MECHANISM FOR SLOPE STABILIZED WITH PILES

2012 ◽  
Vol 18 (5) ◽  
pp. 701-708 ◽  
Author(s):  
Mehmet Rifat Kahyaoglu ◽  
Okan Onal ◽  
Gökhan Imançlı ◽  
Gürkan Ozden ◽  
Arif S. Kayalar
Keyword(s):  
Load Transfer ◽  
Soil Surface ◽  
Time Lapse ◽  
Pile Head ◽  
Soil Pressure ◽  
Soil Arching ◽  
Recording Time ◽  
Pile Spacing ◽  
Stabilizing Piles ◽  
The Moment

In this study, the effects of pile spacing and pile head fixity on the moment and lateral soil pressure distribution along slope stabilizing piles are investigated. A slice from an infinitely long row of piles with fixed pile tip in an inclined sand bed was simulated with an experimental test setup. Surficial soil displacements were monitored and relative displacements between soil particles were determined by recording time-lapse images during the test in order to observe the soil arching mechanism on the soil surface. The load transfer process from moving soil to piles and behavior of soil around piles were observed and evaluated by the different test setups. It was observed that decrease in pile spacing causes an increase of load carried per pile. This behavior, which was significantly influenced by the pile head boundary conditions, can only be explained by soil arching that existed between the piles along their lengths.

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