scholarly journals Computer-Aided Design for Estimating Foundation Uplift on Expansion Soils

1999 ◽  
Vol 4 ◽  
pp. 23
Author(s):  
Adnan A. Basma ◽  
Amer Ali Al-Rawas
Keyword(s):  
Computer Aided Design ◽  
Applied Pressure ◽  
Clay Content ◽  
Unit Weight ◽  
Initial Water Content ◽  
Initial Water ◽  
Swell Percent ◽  
Actual Field ◽  
Semi Arid Region

This work presents a methodology to determine in-situ heave of foundations due to soil expansion. A total of 206 soil specimens from a semi-arid region (lrbid city in northern Jordan) were tested in the laboratory to produce a model for predicting the swell percent, SP. The results indicate that SP is strongly dependent on the placement conditions (initial water content and dry unit weight), clay content of the soil and the initial applied pressure. Utilizing this model, an Advanced BASIC computer program was written to evaluate in-situ heave. It was verified using actual field data: The program provides a Simple means for approximately determining foundation heave.

scholarly journals In situ real-time 3D observation of porosity growth during composite part curing by ultra-fast synchrotron X-ray microtomography

2019 ◽  
Vol 53 (28-30) ◽  
pp. 4105-4116 ◽  
Author(s):  
Basile de Parscau du Plessix ◽  
Patrice Lefébure ◽  
Nicolas Boyard ◽  
Steven Le Corre ◽  
Nicolas Lefèvre ◽  
...  
Keyword(s):  
Applied Pressure ◽  
Conversion Degree ◽  
Initial Water Content ◽  
Initial Water ◽  
Experimental Development ◽  
X Ray ◽  
Size Evolution ◽  
Curing Cycle ◽  
Fibre Reinforced Composites

The present study reports on an experimental development addressing 3D void growth in epoxy-based carbon fibre-reinforced composites during their curing process. For that purpose and to investigate autoclave condition effects, composites samples were cured according to different curing cycles by using a specially designed device, which was installed on a synchrotron beamline dedicated to ultra-fast X-ray microtomography. Thus, 3D in situ images of the voids evolution could be obtained as a function of time, temperature, pressure, initial water content and resin conversion degree, which are the driving factors of void size evolution during the polymerization cycles. Results confirm the combined roles of humidity and temperature on the porosity growth and highlight the complex shape of the generated bubbles. It is also emphasized that a sharp increase of the applied pressure during the curing cycle instantaneously reduces the pore size. Such results improve the understanding of the cure of composites parts and can finally be used as input data for modelling purpose or for validation of existing models.

Effect of Heating Borehole Spacing on Plasticity of Expansive Soil

2020 ◽  
Vol 38 (7A) ◽  
pp. 1062-1068
Author(s):  
Falah H. Rahil ◽  
Husam H. Baqir ◽  
Nabeel J. Tumma
Keyword(s):  
Water Content ◽  
Representative Sample ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Heating System ◽  
Unit Weight ◽  
Initial Water Content ◽  
Initial Water ◽  
Dry Unit Weight ◽  
Laboratory Models

This paper presents the effect of spacing between boreholes heating on plasticity of expansive soils. The expansive soils used were prepared artificially by mixing Kut clay with different percentages of bentonite. Nine laboratory models of expansive soils having dry unit weight of 17.8 kN/m3 with 6% initial water content were prepared inside a steel box of (300 mm × 300 mm × 400 mm height).  A special heating system generates 400 Co for six hours was designed and manufactured for this purpose using 12 mm diameter electric heaters inserted through boreholes. Square pattern boreholes of 170 mm length with spacing (4.16d, 6.25d and 8.33d) were used. A representative sample were taken after heating from the center of the square pattern for measuring the plasticity of the soils. The results showed that the plasticity index remarkedly decreases compared with that before heating and increases with increasing bentonite and the spacing. It is also indicated that an expansive soil could be changed from high to low plasticity

Comparison on the failure process and mechanism between a debris flow and a landslide dam

2020 ◽  
Author(s):  
Huayong Chen ◽  
Chunran Cao ◽  
Xiaoqing Chen ◽  
Jiangang Chen
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Failure Process ◽  
Landslide Dam ◽  
Clay Content ◽  
Peak Discharge ◽  
Initial Water Content ◽  
Dam Breach ◽  
Initial Water ◽  
Landslide Dams

<p>Besides the numerous artificial dams, there are some other kind of dams distribute such as the glacier dams, moraine dams, landslide dams, and the debris flow dams in China. Especially, the landslide dams and debris flow ones widely distribute in southwest of China after the M8.0 Wenchuan earthquake. Much attention has been paid to the formation, stability, breach process, and the peak discharge prediction of a landslide dam. However few achievements are obtained on the debris flow dams even if the failure of a debris flow dam has posed great threat to the property and life of residents downstream. In this paper, based on the main difference between a landslide and debris flow dam, experiments were conducted by considering different clay content, the initial water content, and incoming water flow. It indicated that the failure duration of a debris flow dam was about 1.60 times as long as that than that of a landslide dam. The peak discharge at the debris flow dam breach was 5.38 L/s. However, the peak discharge at the landslide dam was 7.50 L/s, which was 1.39 times as big as that of a debris flow dam. Finally, by modifying the existing critical initialization condition for the landslide dams, the critical initialization condition for a debris flow dam was proposed.</p>

Freezing cycle effects on water stability of soil aggregates

2013 ◽  
Vol 93 (4) ◽  
pp. 473-483 ◽  
Author(s):  
Daryl F. Dagesse
Keyword(s):  
Water Content ◽  
Structural Stability ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Clay Content ◽  
Initial Water Content ◽  
Water Stability ◽  
Initial Water ◽  
Freeze Thaw ◽  
Freezing Cycle

Dagesse, D. F. 2013. Freezing cycle effects on water stability of soil aggregates. Can. J. Soil Sci. 93: 473–483. The freezing process is commonly implicated as a key factor in defining the state of soil structural stability following the winter months. Controversy exists, however, regarding the efficacy, and even the net effect, of this process. The objective of the study was to establish the separate effects of the freezing, freeze–thaw and freeze-drying processes in defining soil structural stability following the over-winter period. Aggregates from soils of varying clay content (0.11, 0.33, 0.44 kg kg−1) and initial water content (0.10, 0.20 or 0.30 kg kg−1) were subjected to freeze-only (F), freeze–thaw (FT) and freeze-dry (FD) treatments. Post-treatment aggregate stability determination was via wet aggregate stability (WAS) and dispersible clay (DC). Freezing alone and freeze-dry treatments generally resulted in greater aggregate stability, while the freeze–thaw generally resulted in lower aggregate stability as compared with a control, not frozen treatment (T). These data suggest the freezing-induced desiccation process improves aggregate stability, while the addition of a thaw component following freezing, with the attendant liquid water, is responsible for degradation of aggregate stability. Clay content and initial water content are important factors governing the magnitude of this process.

Runoff Quantity Dynamic from an Extensive Green Roof during Individual Rainstorms

2011 ◽  
Vol 250-253 ◽  
pp. 3429-3435
Author(s):  
Jian Jun Ye ◽  
Hua Zhang ◽  
Shi Xiao Yu ◽  
Sheng Bo Guo ◽  
Wen Nian Xu ◽  
...  
Keyword(s):  
Peak Flow ◽  
Green Roof ◽  
Central China ◽  
Initial Water Content ◽  
Unit Hydrograph ◽  
In Situ Tests ◽  
Initial Water ◽  
Extensive Green Roof ◽  
S Curve

This study evaluates the influence of an extensive green roof on runoff quantity dynamic during individual rainstorms in Central China. Controlled experiments on a simulated extensive green-roof plot were carried out firstly to produce a unit hydrograph (UH) by the methods of S-curve linearization treatment and curve fitting. Then in situ tests were conducted to compare runoff quantity per minute from the green roof plot and a conventional roof plot to verify the obtained UH and compare their runoff quantity dynamic during two rain storms in the year of 2009.The obtained UH is able to predict accurately peak flows and runoff volumes for any rain input. When the initial water content of the substrate was dry, the 7 cm thick green roof can delay the runoff initiating for nearly 8 minutes, lower runoff peak and volume by about 50% compared with conventional roof during a 10.1mm rainstorm on 7 June; and even when the substrate was wet, the extensive green roof can detain runoff effectively by 129 min longer than conventional roof and thus lower the peak flow of runoff by 43% during a 6.3 mm rainstorm on 12 March.

Effect of Coefficient of Variation on the Reliability of Collapse Potential's Equation Predicted by ANNs

2020 ◽  
Vol 857 ◽  
pp. 195-202
Author(s):  
Ahmed M. Najemalden ◽  
Salah W. Ibrahim ◽  
Mahmoud D. Ahmed
Keyword(s):  
Soil Properties ◽  
Reliability Analysis ◽  
Coefficient Of Variation ◽  
Prediction Equation ◽  
Degree Of Saturation ◽  
Unit Weight ◽  
Initial Water Content ◽  
Initial Water ◽  
Potential Equation ◽  
Collapse Potential

In this paper, the Reliability Analysis with utilizing a Monte Carlo simulation (MCS) process was conducted on the equation of the collapse potential predicted by ANN to study its reliability when utilized in a situation of soil that has uncertainty in its properties. The prediction equation utilized in this study was developed previously by the authors. The probabilities of failure were then plotted against a range of uncertainties expressed in terms of coefficient of variation. As a result of reliability analysis, it was found that the collapse potential equation showed a high degree of reliability in case of uncertainty in gypseous sandy soil properties within the specified coefficient of variation (COV) for each property. When the COV ranges (0-100) for each soil properties under study, it was found also that the collapse potential equation is very well in predicting the collapse potential of gypseous sandy soils for all values of the COV lies between (0-100) % for initial water content and degree of saturation, and for values of the COV not exceed 11%, 19% for the initial dry unit weight and specific gravity respectively, as well as for the values of the COV not exceed 80%, 97% for the initial voids ratio and gypsum content respectively.

scholarly journals Pengaruh Kadar Air Awal Dan Surcharge Pressure Pada Uji Karakteristik Pengembangan Tanah Ekspansif

2017 ◽  
Vol 23 (2) ◽  
pp. 124
Author(s):  
Wilis Diana ◽  
Edi Hartono ◽  
Anita Widianti
Keyword(s):  
Water Content ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Dry Density ◽  
Initial Water Content ◽  
Expansive Clay ◽  
Initial Water ◽  
Swelling Properties ◽  
Swell Percent ◽  
Swell Pressure

Expansive soils experience volumetric changes due to water content changes. These volumetric changes cause swell and shrink movement in soils, which in turn will inflict severe damage to structures built above them. A Proper understanding of how the expansive soil behaves during the wetting/drying process is essential for assessing the mitigation action of expansive soil hazard and design suitable foundation. The structures that build above expansive soil bed are susceptible to heave and to withstand swell pressure, thus the swell pressure must be considered in the design. This study focuses on swelling properties of two expansive clay from Ngawi, East Java and Wates, Yogyakarta. Laboratory test on disturbed samples is used to identified and to measured swelling properties. A series of swelling test was performed under constant soil dry density. The influence of initial water content and surcharge pressure on swelling properties (i.e swell percent and swell pressure) of compacted samples were investigated. The swelling properties test used ASTM standard 4546-03 method B. It was found that the lower initial water content the higher the swell percent, but the swell pressure seems not to be affected by initial water content. At the same initial water content, swell percent decrease with the increase of surcharge pressure, but swell pressure remains unchanged.

Evaluating Soil Water Matric Pressure and Sorptivity Relationship as Affected by some Properties of a Clay Soil

2022 ◽  
Author(s):  
Gülay Karahan
Keyword(s):  
Soil Properties ◽  
Clay Soil ◽  
Clay Content ◽  
Initial Water Content ◽  
Key Factors ◽  
Initial Water ◽  
Infiltration Process ◽  
Undisturbed Soil ◽  
Disc Infiltrometer ◽  
The Relationship

Sorptivity (S) is the fundamental variable controlling the early infiltration process. Besides soil properties, soil initial water content (θi) and/or matric pressure (hi) are key factors determining extent of S. Assessment of interrelationship among S, hi and soil properties can provide a considerable insight into understanding the behaviour of dry soils to rainfall or irrigation water. This study was conducted to evaluate relationship between S and some selected soil parametric and morphometric properties within a range of hi. Sixteen undisturbed soil samples (5 cm id, 5 cm length) were taken from the topsoil (0-15 cm) of a paddy soil with clay texture. Sorptivity was measured with a mini-disc infiltrometer (MDI) on the samples equilibrated at h, ranging from -20 to -1500 kPa. A parameter (η), representing the relationship between S and hi, was introduced. Correlation analysis was conducted between η and selected soil morphometric and parametric properties. Soil structure and clay content appeared the most important soil attributes influencing S-hi relation between -200 and -1500 kPa. The results provided a fundamental understanding on S-hi-soil properties interrelations in a clay soil. The methodology developed in this study can be used to evaluate S-hi relationship across different soils and scales.

Investigation of three methods for evaluating swelling pressure of soils

2000 ◽  
Vol 6 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Mousa F. Attom ◽  
Samer Barakat
Keyword(s):  
Mathematical Models ◽  
Clay Content ◽  
Swelling Pressure ◽  
Initial Water Content ◽  
Clayey Soils ◽  
Initial Water ◽  
Pressure Method ◽  
Free Swell ◽  
Northern Jordan

Abstract Determination of the swelling pressure of six types of clayey soils obtained from northern Jordan were measured using three methods, the Free Swell method, Different Pressure method, and the Zero Swell method. These methods show different values in swelling pressure of the soil. For all six soils, the Free Swell method provided the highest value, whereas the Different Pressure method provided the lowest. Discrepancy in the value of swelling pressure among the methods increases with lower initial water content, higher plasticity index, and clay content. This paper compares the three different methods for evaluating soil swelling pressure and presents mathematical models to predict the soil swelling pressure for each method.

Influence of initial water content and strain rate on remolded yield stress in marine clay

2021 ◽  
pp. 1-8
Author(s):  
Xiaobing Li ◽  
Jianpeng Chen ◽  
Xiuqing Hu ◽  
Hongtao Fu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Water Content ◽  
Yield Stress ◽  
Initial Water Content ◽  
Marine Clay ◽  
Initial Water
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