scholarly journals Experimental Study on Frost-Heaving Force Development of Tibetan Clay Subjected to One-Directional Freezing in an Open System

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pengfei He ◽  
Meng Xiong ◽  
Yanhu Mu ◽  
Jianhua Dong ◽  
Xinlei Na

Frost heave of soils involves complex coupled interactions among moisture, heat, and stress, which can cause serious damage to cold regions engineering. In this paper, a series of one-directional freezing experiments were implemented for the Tibetan clay with rigid restraint in an open system. The varying characteristics of the temperature, frost-heaving force, and water replenishment during the freezing process were analyzed under different freezing temperatures (−5, −7, and − 9°C), dry densities (1.65, 1.7, and 1.75 g cm−3), and initial moisture contents (11, 14, and 17%) of the soil samples. It was concluded that the freezing of soil samples mainly occurred within 10–25 hours from the beginning of the experiment; hereafter, the soil temperatures tended to be stable. The development of frost-heaving force could be divided into three stages as slow increase, quick increase, and relative stable stages. Low freezing temperature, large dry density, and high moisture content were all the contributors to the frost-heaving process of the soil, which could increase the freezing depth, magnitude of the frost-heaving force, and amount of water replenishment. The variations in water replenishment from the open system corresponded to the three stages of the frost-heaving force but had time lags. The moisture contents at different layers of soil samples were measured after the freezing experiment. The results showed that the freeze part of soil samples experienced a significant wetting, while the unfrozen part experienced drying during the experiment. The degrees of wetting and drying were related to the freezing temperature, dry density, and initial moisture content of the soil samples. The experiment results could provide data support for theoretical study on moisture, heat, and stress coupling in freezing soil.

Author(s):  
Y. A. Unguwanrimi ◽  
A. M. Sada ◽  
G. N. Ugama ◽  
H. S. Garuba ◽  
A. Ugoani

Draft requirements of two animal – drawn (IAR) weeders operating on loam soil were determined in the study. The implements include a straddle row weeder and an emcot attached rotary weeder evaluated under the same soil conditions, using a pair of white Fulani breed of oxen. The animal draft requirement was first estimated from the animal ergonomics measurements. Using area of 0.054 hectare as experimental plot for each implement the draft requirement of each implement was investigated after taking soil samples for soil moisture content and bulk density determinations. The implements tested showed variation in their average draft requirement. The straddle row weeder had the highest value of 338.15 N respectively while the emcot attached rotary weeder had the lowest value of 188.12 N with 47.03%, respectively. The average soil moisture contents and bulk density were 13.0% and 1.46%/cm3, respectively.


2018 ◽  
Vol 250 ◽  
pp. 01008
Author(s):  
Tuan Noor Hasanah Tuan Ismail ◽  
Siti Aimi Nadia Mohd Yusoff ◽  
Ismail Bakar ◽  
Devapriya Chitral Wijeyesekera ◽  
Adnan Zainorabidin ◽  
...  

Soils at many sites do not always have enough strength to bear the structures constructed over them and some of the soil may need to be stabilized in order to improve their geotechnical properties. In this paper, routine laboratory tests were critically carried out to investigate the efficacy of lignin in improving the strength behaviour of the soils. Two different soil samples (laterite and kaolin) were studied and mixed with different proportions of lignin (2% and 5% of dry weight of soil), respectively. Unconfined Compressive Strength (UCS) characteristics evaluated in this study were done on samples at their maximum dry density and optimum moisture content (obtained from compaction tests). The UCS tests on all the specimens were carried out after 0, 7, 15, 21 and 30 days of controlled curing. The research results showed that the addition of lignin into kaolin reduced its maximum dry density while giving progressively higher optimum moisture content. Contrarily, with the laterite soil, both maximum dry density and optimum moisture content simultaneously increased when lignin was added into the soils. The UCS results showed that the the stabilized laterite with 2% lignin continued to gain strength significantly at a fairly steady rate after 7 days. Unfortunately, lignin did not show a significant effect in kaolin.


2020 ◽  
Vol 3 ◽  
pp. 12-25
Author(s):  
Olaoluwa Oluwaniyi ◽  
Imoleayo Fatoyinbo ◽  
Akinola Bello ◽  
Joshua Owoseni

Failure of highway pavement and collapse of building in basement complex of Nigeria is often related to the instability of the residual. This study evaluated the strength characteristics of gneiss-derived residual Soils as materials usable for road pavement structures. A total of eleven soil samples derived from granite gneiss were subjected to laboratory geotechnical analyses based on standard practices. The geotechnical analyses reveal the soils’ natural moisture content, specific gravity, grain sizes, consistency limits, shearing strengths, maximum dry density, and optimum moisture content. Based on AASHTO classification, the soil samples are classified as A-7-6, A-6, and A-7-5. The results of the laboratory analyses revealed that the natural moisture content and specific gravity ranged from 8.30 to 22.70% and 2.6 to 2.8 respectively. Particle size analysis reveals that the coarse contents of the soils ranged from 28.8% to 59.8% and amount of fines ranged from 40.2 to 71.2%. The liquid limit ranged from 31.3% to 68.3%, plastic limit ranged from 20% to 28.0%, plasticity index ranged from 4.8% to 38.90% and linear shrinkage ranged from 5.7 to 13.6%. The maximum dry density ranged from 1481 kg/m3 to 1921 kg/m3 and optimum moisture content ranged from 15.2% to 27.6%. Undrained triaxial shear strength (Cu) ranged from 43.0 Kpa to 250.3Kpa, angle of friction ranges from 11.7 to 29.30, and unconfined compressive strength ranged from 153 to 356.5Kpa. The results indicate that the residual soils are poor sub-grade and foundation materials due to their high amount of fines, linear shrinkage values, plasticity, and swelling potential, as well as low maximum dry density.


2020 ◽  
Vol 6 ◽  
pp. 24-32
Author(s):  
Muhammad Israil ◽  
Muhammad Ashraf ◽  
Muhammad Fahim ◽  
Rashid Rehan ◽  
Sajjad Wali Khan ◽  
...  

This study presents experimental investigation of indigenous clays mixed with Bentonite to assess their suitability in potential use as clay liners. Soil samples with 0, 4, 8, and 12% Bentonite content from three different sites in Peshawar region were tested for various geotechnical properties. Grain size distribution, specific gravity, Atterberg limits and free swell were found through laboratory tests using appropriate ASTM procedures. Maximum dry density and optimum moisture content were calculated using Atterberg limits in available relationships. Finally, one dimensional consolidation tests were conducted to find relevant parameters for calculating hydraulic conductivity. A decrease in specific gravity, increase in free swell, and in optimum moisture content, decline in maximum dry density and hydraulic conductivity was observed with increase in Bentonite content across all three soil samples. During free swell, the soil clusters become larger leading to formation of floccules resulting in the narrowing of inter-particle space and thus blocking of permeable paths. It is concluded that 8% Bentonite content by weight yields a suitable mixture for a clay liner that has hydraulic conductivity in the range of recommended limits.


Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 468-471 ◽  
Author(s):  
David McAuliffe ◽  
Arnold P. Appleby

Ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] was applied to dry soils (2%, w/w moisture content) that were either wetted immediately or remained dry for 1 to 8 days prior to wetting. Two degradation products were isolated with thin-layer and column chromatography from soils that were kept dry for 4 days before wetting. The major product was identified as 2,3-dihydro-3,3-dimethyl-2-oxo-5-benzofuranyl methanesulfonate which accounted for more than 80% of the degradation products. The products were detected 1 day after application to dry soil (between 1 and 3% moisture content), while at moisture contents greater than 3% (w/w) very little ethofumesate was degraded. Radiolabeled ethofumesate and breakdown products were extracted with methanol from dry and wetted soils, and the soil samples were oxidized to quantify nonextractable radioactivity. The percentage of nonextracted ethofumesate was at least 5% greater in dry soil than in wet soil. Activity loss of ethofumesate applied to dry soil probably is due to both chemical degradation and strong adsorption.


2012 ◽  
Vol 446-449 ◽  
pp. 1842-1845
Author(s):  
Xiao Yue Wang ◽  
Jie Cao ◽  
Rui Hua Zheng

Centrifuge model tests were conducted to investigate the behavior of cohesive soil foundations during a construction of an embankment, considering different dry densities and moisture contents of the soil. During the construction, the deformation of soil foundation gradually increased and reached the peak value at the top of the foundation near the center of embankment. After the embankment was completed, the deformation of the foundation continued increasing. The dry density and moisture content of the soil significantly affected the deformation process of the foundation.


2018 ◽  
Vol 149 ◽  
pp. 02032 ◽  
Author(s):  
A M Elsharief ◽  
Mai Sufian

This paper investigates the development of swelling with time for a highly plastic and potentially expansive clay from Sudan. Soil samples were prepared in the laboratory at different moisture content values. The prepared samples were placed in the oedometer ring at three density levels and then placed in an oedometer cell which allows one dimensional swelling. Swelling was observed at different time intervals to 48 hours. The data was analyzed to determine the development of swelling with time. The data analysis clearly demonstrated three stages of swelling, initial, preliminary and secondary for all tested samples except the quasi-saturated ones. The swell percent and primary swelling were very sensitive to the initial moisture content and dry density of the tested samples. Most of the swelling took place during the first 24 hours for all the tested specimens. The hyperbolic model was assessed for prediction of the percent swell. The 12 hours data was found to be very successful in predicting the percentage swell.


Author(s):  
S.V. Satyanarayana ◽  
Mohammed Al Jahwari

In the Gulf region most of the soils require soil stabilization to increase soil bearing capacity for construction of safe and sustainable buildings. The soils are stabilized either by physical stabilization, chemical stabilization or by mechanical stabilization. The aim of this project is to stabilize calcareous soil in the Barka region with synthetic polymers. The soil samples from the Barka region collected by using standard soil sampling methods. The synthetic polymer was mixed with the calcareous soil in 1%, 3% and 5%. The soil samples were tested for sieve analysis, Atterberg Limit, Particle Density, Proctor test and California Bearing Ratio test before and after addition of synthetic polymer. It was observed that there is a positive impact on the geotechnical properties of soil with the addition of Polymer. The optimum moisture content of the soil reduced and the maximum dry density of the soil increased. The optimum results were found at 5% addition of polymer where the optimum moisture content was found out to be 12.6% and the maximum dry density was found out to be 1.997 Mg/m3. The Atterberg limit test to show that the plasticity index of the soil reduced with the addition of polymer and the optimum results were found out at 5% addition of polymer. Finally, the CBR test results determine that the soil bearing capacity increases with the addition of Polymer. After the addition of 5% Polymer, the CBR value was found out to be 27.465% compared to 14.19% for the fresh calcareous soil. The results are encouraging. Keywords: Atterberg Limit, Calcareous soil, CBR, polymer, stabilization.


2020 ◽  
Vol 8 (2) ◽  
pp. 35
Author(s):  
Thompson Henry Tolulope Ogunribido ◽  
Tunde Ezekiel Fadairo

Twenty soil samples collected from the failed portions in the study area were air dried for two weeks before analyses. Each soil samples were subjected to eight engineering tests which include: natural moisture content, atterberg limit, specific gravity, compaction, unconfined compressive strength, California bearing ratio, grain size and hydrometer analysis. Results showed that the natural moisture content ranged from 17.7% to 37.8%, liquid limit from 48.5% to 62.4%, plastic limit from 18.3% to 26.8%, plasticity index from 25.7% to 37.7%, shrinkage limit from 5.8%-12.5%, optimum moisture content from 14.2% to 32.4%, maximum dry density from 1301 Kg/rn3 to 2002 Kg/rn3. Soaked California bearing ratio ranged from 5% to 17%, unsoaked from 15% to 38%, specific gravity from 2.5 to 2.68, unconfined compressive strength r from 112.8 Kpa to 259.7 Kpa, shear strength from 56.4 Kpa to 129.9 Kpa and hydrometer analysis from 48.5% to 72.1%. Based on the Federal Government specifications for pavement construction, for the soil to be suitable, stabilization with bitumen, Portland cement, lime, coal fly ash, and saw dust should be done. Road pavement failure along Arigidi – Oke Agbe road was due to poor engineering geological condition of the sub-grade soils and poor drainage systems.  


2020 ◽  
Vol 8 (1) ◽  
pp. 22
Author(s):  
G.O Adunoye ◽  
A.A Ojo ◽  
A.F Alasia ◽  
M.O Olarewaju

The importance of soil compaction for civil engineering construction and application cannot be over-emphasised. To perform soil compaction, numerous number of samples are required, with considerable time and laborious laboratory activities. This has necessitated the need to find models for the prediction of compaction characteristics, using easily determined soil properties. This work therefore undertook a study of the correlation potential of compaction characteristics and Atterberg limits of soils, with a view to modelling compaction characteristics, using Atterberg limits. To achieve this aim, soil samples were obtained from selected locations within Obafemi Awolowo University campus, Ile-Ife, Nigeria. Preliminary, Atterberg limits and compaction tests were conducted on the soil samples, using standard procedure. Using Microsoft Excel and Xuru’s Regression tool, the laboratory test results were used to develop relationships between compaction characteristics (optimum moisture content and maximum dry density) and Atterberg limits (liquid limit and plastic limit). Results showed that the natural moisture content of soil samples ranged between 4.97 % and 19.72 %; liquid limit ranged between 27 % and 68 %; plastic limit ranged between 18.92 % and 63.01 %; and plasticity index ranged between 0.94 % and 14.63 %. The optimum moisture content ranged between 6.7 % and 27 %, while the maximum dry density ranged between 1560 kN/m3 and 2260 kN/m3. The results of regression analysis showed that the combination of liquid limit and plastic limit has a strong correlation with optimum moisture content (R2 = 0.870); while the combination (of liquid limit and plastic limit) showed a weak correlation with maximum dry density (R2 = 0.150). The study concluded that liquid limit and plastic limit could be used to estimate the optimum moisture content of the soils, by applying the developed relationship/equation.  


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