Journal articles on the topic 'Expansive soils'
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Yang, Hai Ying, and Yun Liu. "Methods of Support Vector Machine on Classification of Expansive Soils." Advanced Materials Research 531 (June 2012): 562–65. http://dx.doi.org/10.4028/www.scientific.net/amr.531.562.
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The classification of the grade of shrink and expansion for the expansive soils was the initial and essential work for engineering construction in expansive soil area. Based on the principle of support vector machine analysis, a classification model of expansive was established in this paper, including five indexes reflecting the shrink and expansion of expansive soil, liquid limit, swell-shrink total ratio, plasticity index, water contents and free expansive ratio and functions were obtained through training a large set of expansive samples. It was shown that the classification model of SVM analysis is an effective method performed excellently with high prediction accuracy and could be used in practical engineering.
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Samidurai, V. "Influence of Flyash on expansive Soils." International journal of Emerging Trends in Science and Technology 03, no. 03 (March 22, 2017): 4998–5003. http://dx.doi.org/10.18535/ijetst/v4i3.03.
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Xu, Li Li, Xiang Min Qu, and Li Jia Liu. "Experimental Study on Expansion Characteristics, Frost Heaving Characteristics of EPS Beads Improved Expansive Soils." Advanced Materials Research 742 (August 2013): 80–84. http://dx.doi.org/10.4028/www.scientific.net/amr.742.80.
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Proposed EPS beads for the improvement of expansive soil in cold regions. Based on laboratory soil test study the feasibility and mechanism of the EPS beads improving expansive soils. Through four sets of comparative test with different contents of the EPS beads, the result indicates: The expansion rate of the soil, frost heave amount decreases with the increase in EPS beads content, EPS beads can effectively inhibit the expansion of expansive soil and frost heaving, proposed the optimal dosage.
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Wang, Ming Wu, Kang Ge, and Da Rong Zhu. "Experimental Study of Engineering Behaviors on Improved Expansive Soils in the Xinqiao Airport Runway of Hefei." Advanced Materials Research 261-263 (May 2011): 1329–35. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1329.
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Foundation treatment of expansive soils is a complex worldwide problem. Herein engineering behaviors of expansive soils and improved expansive soils with lime (IESL) in the runway area of Xinqiao international airport of Hefei were investigated by means of laboratory experiments and field tests. It was concluded that the expansive soils of mean plasticity index 24.2, and optimum moisture content of 16% in the engineering area, behaved weak and medium expansive potential. The plastic index of improved expansive soil of 7% lime mixed indoor and of 8% lime incorporated on site dropped to 20 and 13. At the same time, the free swelling ratios of IESL reduced up to 6.31 % and 3% relative to 46.5% of expansive soil, and the swelling pressure also decreased from 67.5 kPa to 4.05 and 11.28 kPa, respectively. The mean unconfined compression strength of improved expansive soil of 7 % lime on site was 853 kPa, 71% stronger of that of expansive soils. And the soil response modulus was up to 235.2 MN/m3, 9 times of expansive soils. It was also found form the immersion tests on site that the swell value of IESL was only 30% at most of expansive soils at the same depth. These results indicate that the compacted IESLs have a good bearing capacity, strength and water stability, so the engineering behaviors of IESLs are much better than those of expansive soils, and prove that the modification plan, expansive soils incorporated 7% lime on site could meet the design requirements.
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Yang, He-Ping, Jian-Long Zheng, and Rui Zhang. "Addressing Expansive Soils." Civil Engineering Magazine Archive 77, no. 3 (March 2007): 62–69. http://dx.doi.org/10.1061/ciegag.0000112.
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Chakravarthy, Thokala, and K. Shyam Chamberlin. "Fly ash and bagasse ash embankment in flexible pavements for the analysis and strengthening of black cotton soil’s strength stabilized properties." E3S Web of Conferences 391 (2023): 01005. http://dx.doi.org/10.1051/e3sconf/202339101005.
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Soil stabilization is necessary to increase the soil’s durability, volume stability, and engineering expansion strength. Expansive soils (also known as black cotton soil), a problem that affects the entire world and poses various challenges for civil engineers, are extremely hard while dry but completely lose their strength when wet. In this study, fly ash has been employed to stabilize the soil. Five, ten, twenty, and twenty-five percent of fly ash was used in the experiments. Bagasse ash is an easily accessible byproduct of the sugar cane refining process that has negative environmental effects. In this study, any potential pozzolanic benefits are evaluated while taking into account bagasse ash. material that stabilizes elongated soil In order to examine the soils’ geotechnical characteristics, the experimental investigation focuses on altering the fly ash content of the soils. The goal is to learn more about the characteristics of black cotton soil’s tensile strength. The primary goal of this research is to examine the effects of bagasse ash on the engineering expansive soil’s properties as revealed by various lab tests, and after improving the treated soil through embankment work at various civil engineering activities, such as roadways.
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Zamin, Bakht, Hassan Nasir, Muhammad Ali Sikandar, Waqas Ahmad, Beenish Jehan Khan, Mahmood Ahmad, and Muhammad Tariq Bashir. "Comparative Study on the Field- and Lab-Based Soil-Water Characteristic Curves for Expansive Soils." Advances in Civil Engineering 2022 (May 2, 2022): 1–9. http://dx.doi.org/10.1155/2022/6390442.
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Expansive soils are problematic and viewed as a potential hazard for buildings and structures due to swell and shrink phenomena. The damaging effect of these soils is strongly correlated with the soil-water characteristics of expansive soils present in the shallow depth. The seasonal wetting-drying cycle is vital in fluctuating moisture content in the surficial soils. As such, soils remain unsaturated most of the time due to high absorption capacity. Therefore, it is crucial to assess them as unsaturated soil, and the soil-water characteristic curve (SWCC) is an essential tool for measuring unsaturated soils’ mechanical and hydraulic properties. The main objective of this study was to establish both field- and lab-based SWCCs for the expansive soils and compare them for determining the possible difference between them. For this purpose, eight sites of expansive soils were selected for sampling and in situ testing. These sites include three locations of Karak, three locations of Kohat, and two locations of D.I areas. Based on the experimental results, Karak’s expansive soil indicated a high suction value of 705 kPa, while D. I Khan’s soil showed the least suction equal to 595 kPa. The comparison of field and lab SWCCs for the potential sites presented a close agreement in the matric suction values beyond the air entry values (AEVs), particularly in the residual suction zones. It was also concluded that for expansive soils, the field- and lab-based SWCCs are comparable beyond the AEVs. The established curves can be successfully utilized to assess local expansive soils in the framework of unsaturated soils.
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Wei, Jianhu, Jianmeng Wei, Qijun Huang, Sheikh Mohd Iqbal Bin S. Zainal Abidin, and Zhenjie Zou. "Mechanism and Engineering Characteristics of Expansive Soil Reinforced by Industrial Solid Waste: A Review." Buildings 13, no. 4 (April 10, 2023): 1001. http://dx.doi.org/10.3390/buildings13041001.
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Expansive soils exhibit detrimental swelling and shrinking characteristics in response to variations in water content, posing a threat to engineering safety. Utilizing industrial solid waste for improving the engineering properties of expansive soil presents a promising solution due to its low pollution and high recoverability. This paper reviews the progress of research on various industrial solid wastes in stabilizing expansive soil. The review comprehensively discusses the microscopic characteristics and mechanism of industrial solid waste-stabilized soils, as well as their impact on the compressive strength, shear, compaction characteristics, consistency, swelling and shrinkage properties, and durability of expansive soils. The addition of appropriate curing agents or the combination with other stabilizing materials can enhance the strength of expansive soil, mitigate volume changes, and improve the durability and stability of expansive soils. The mechanisms of stabilization of expansive soils by industrial solid waste involve cation exchange, flocculation-agglomeration, pozzolanic reaction, and carbonation. Additionally, microscopic characterization analysis reveals that the formation of C-S-H and C-A-H is the primary contributor to the improvement of soil geotechnical properties.
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Zhang, Shaowei, and Dongdong Li. "The Effects of Salt-Lake Salt Solution on the Strength of Expansive Soil." Geofluids 2022 (April 19, 2022): 1–8. http://dx.doi.org/10.1155/2022/2798281.
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Expansive soils are widely distributed and often cause serious damage to structures. Hanzhong expansive soil and Yulin salt-lake solution were adopted to investigate the effect of salt-lake salt solution on the strength of expansive soil. Expansive soils modified with salt-lake salt solutions with different concentrations (0.1, 0.5, and 1.0 mol/L) were evaluated by X-ray diffraction (XRD), Atterberg limit, free swelling, no load swelling ratio, and triaxial compression tests. The improved expansive soil research using salt-lake salt solution was carried out based on the macroscopic mechanical characteristics. Test results showed that the addition of salt-lake solution effectively inhibited the expansibility of soil. With the increase of the concentration of salt-lake solution, liquid limit, plastic limit, plastic index, free expansion rate, no load swelling, cohesion, and internal friction angle of expansive soil were decreased in varying degrees, and stress-strain relationship curve gradually showed strain softening trend. The reason for the above results was believed to be that salt-lake salt solution reduced the force between particles on shear surface and reduced mutual hindrance.
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Houston, Sandra, and Xiong Zhang. "Review of expansive and collapsible soil volume change models within a unified elastoplastic framework." Soils and Rocks 44, no. 3 (July 8, 2021): 1–30. http://dx.doi.org/10.28927/sr.2021.064321.
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Numerous laboratory tests on unsaturated soils revealed complex volume-change response to reduction of soil suction, resulting in early development of state surface approaches that incorporate soil expansion or collapse due to wetting under load. Nonetheless, expansive and collapsible soils are often viewed separately in research and practice, resulting in development of numerous constitutive models specific to the direction of volume change resulting from suction decrease. In addition, several elastoplastic models, developed primarily for collapse or expansion, are modified by add-on, such as multiple yield curves/surfaces, to accommodate a broader range of soil response. Current tendency to think of unsaturated soils as either expansive or collapsible (or, sometimes, stable), has likely contributed to lack of development of a unified approach to unsaturated soil volume change. In this paper, common research and practice approaches to volume change of unsaturated soils are reviewed within a simple macro-level elastoplastic framework, the Modified State Surface Approach (MSSA). The MSSA emerges as a unifying approach that accommodates complex volume change response of unsaturated soil, whether the soil exhibits collapse, expansion, or both. Suggestions are made for minor adjustments to existing constitutive models from this review, typically resulting in simplification and/or benefit to some of the most-used constitutive models for unsaturated soil volume change. In the review of practice-based approaches, the surrogate path method (SPM), an oedometer/suction-based approach, is demonstrated to be consistent with the MSSA framework, broadly applicable for use with expansive and collapsible soils, and yielding results consistent with measured field stress-path soil response.
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Li, Tao, Yanqing He, Guokun Liu, Binru Li, and Rui Hou. "Experimental Study on Cracking Behaviour and Strength Properties of an Expansive Soil under Cyclic Wetting and Drying." Shock and Vibration 2021 (December 26, 2021): 1–13. http://dx.doi.org/10.1155/2021/1170770.
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Expansive soil is characterized by its unique structural morphology and drastic volume change. With infrastructure increasingly constructed in expansive soil areas, engineering problems caused by the properties of expansive soils have attracted more attention. Cyclic wetting-drying and shear testing were accordingly conducted on an expansive soil from Chengdu area in China. Crack development and shear strength change were analyzed using the Mohr–Coulomb equation for shear strength by fitting the experimental data. The results show the following: (1) With the increase in wetting-drying cycles, the crack ratio increases, the shear strength decreases, and the shear strength parameters gradually decrease at the same rate of change. The applied vertical load reduces the weakening effect of the wetting-drying cycles on the soil structure and strength by restraining the expansion and contraction deformation. (2) By analyzing the number of wetting-drying cycles and the crack images, the crack development (length, direction, etc.) of the expansive soil can be predicted and described. (3) There is a specific linear correlation between the crack ratio and strength that approached a limit value with ongoing wetting-drying cycles. The strength of the expansive soil can therefore be obtained based on crack development, improving the ability of designers to account for the behaviour of expansive soils.
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Alemshet, Dereje, Basha Fayissa, Anteneh Geremew, and Gelata Chala. "Amelioration Effect of Fly Ash and Powdered Ground Steel Slag for Improving Expansive Subgrade Soil." Journal of Engineering 2023 (February 27, 2023): 1–9. http://dx.doi.org/10.1155/2023/1652373.
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The utilization of fly ash (FA) and powdered granulated steel slag (PGSS) as additives in soil stabilization plays a crucial role in environmental, economic, and weak soil property improving advantages. In this study, the combined effect of FA and PGSS in improving expansive subgrade soil was investigated. The materials used for this study were expansive soils, FA, and PGSS. The study has applied an experimental research method. For this investigation, the index properties, Free Swell Index (FSI), unconfined compressive strength (UCS), optimum moisture content (OMC), California bearing ratio (CBR), and scanning electron microscope (SEM) tests were done for treated and untreated expansive soils. The findings indicated that as the mixture of FA (0 to 12.5% at 5% increment) and PGSS (0 to 25% at 5% at 2.5% increment) is added to the untreated expansive soils, the index properties, FSI, and OMC of the soils were significantly declined. The CBR values of expansive soils containing 20% FA and 10% PGSS mixture were 13.8% and 16.21%, respectively, which improved the quality of the soils by 85.43% and 84.82%, respectively. While the untreated expansive soils have a UCS value of 0.34 kg/cm2, the treated soil comprising 20% FA and 10% PGSS mixture has a UCS value of 13.42 kg/cm2, indicating that the soil strength is enhanced by 97.47%. The results of the studies demonstrate that adding FA and PGSS to expansive soil improves its stability and strength. The study concluded that disposals such as FA and PGSS might be effectively used in enhancing the characteristics of construction materials and used for the construction.
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Alnmr, Ammar, Richard Paul Ray, and Rashad Alsirawan. "A State-of-the-Art Review and Numerical Study of Reinforced Expansive Soil with Granular Anchor Piles and Helical Piles." Sustainability 15, no. 3 (February 3, 2023): 2802. http://dx.doi.org/10.3390/su15032802.
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Expansive soils exist in many countries worldwide, and their characteristics make them exceedingly difficult to engineer. Due to its significant swelling and shrinkage characteristics, expansive soil defies many of the stabilization solutions available to engineers. Differential heave or settlement occurs when expansive soil swells or shrinks, causing severe damage to foundations, buildings, roadways, and retaining structures. In such soils, it is necessary to construct a foundation that avoids the adverse effects of settlement. As a result, building the structure’s foundations on expansive soil necessitates special consideration. Helical piles provide resistance to uplift in light structures. However, they may not fully stabilize foundations in expansive soils. A granular anchor pile is another anchor technique that may provide the necessary resistance to uplift in expansive soils using simpler methods. This review and numerical study investigate the fundamental foundation treatments for expansive soils and the behavior of granular anchors and helical piles. Results indicate that granular anchor piles performed better than helical piles for uplift and settlement performance. For heave performance, the granular anchor and helical piles perform nearly identically. Both achieve heave reductions greater than 90% when L/H > 1.5 and D = 0.6 m.
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A Putri, Christy, Widjojo A Prakoso, and Wiwik Rahayu. "Review of classification methods to determine expansion degree of expansive soils in Indonesia." E3S Web of Conferences 347 (2022): 03006. http://dx.doi.org/10.1051/e3sconf/202234703006.
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Expansive soils are one of the problematic soils that can cause damage to structures, such as buildings and roads. In Indonesia, the geographical distribution of expansive soils is quite widespread, in many regions including Java, Sumatera, and Papua. This study was conducted by reviewing previous research on the expansion degree of expansive soils. The suitability of the expansion degree indicated by the activity method, Van der Merwe’s criteria, and Chen’s criteria were evaluated by comparing a series of laboratory test results to these criteria. It was observed that the expansion degree indicated by these criteria did not necessarily reflect the actual swelling potential. Other indicators, other than typical index properties, are needed to predict the expansion degree more accurately.
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Martínez, Domingo E., and Gilberto Q. Sotolongo. "Comprehensive Methodology for the Evaluation of Clay Expansiveness. A Case Study." Soils and Rocks 31, no. 3 (September 1, 2008): 145–49. http://dx.doi.org/10.28927/sr.313145.
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Although expansive soils have been widely studied by different authors, just a few have made methodological proposals to comprehensively evaluate this phenomenon. The aim of this paper is to suggest a methodology which will serve as guideline to evaluate soil expansiveness in a comprehensive way. This methodology comprises a series of tasks: identification and classification of potentially expansive soils, estimation of the active zone depth, quantification of the expansion, calculation of heave and choice of a solution.
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G, Venugopal, Sureka Naagesh, and Gangadhara S. "Effect of RBI Grade 81 on Strength Characteristics of Expansive Soil." ECS Transactions 107, no. 1 (April 24, 2022): 15033–42. http://dx.doi.org/10.1149/10701.15033ecst.
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Expansive soils, which are generally termed as problematic soils, cause swelling and shrinkage resulting in significant damage to the structures constructed on them. In this study, an attempt is made to know the effect of Road Building International Grade 81 (RBI Grade 81) on strength characteristics of expansive soil. RBI Grade 81 has a wide range of response spectrum. Response spectrum is the range of soils for which a particular stabilizer can be used. A wide range of tests, such as Atterberg limits, compaction, unconfined compressive strength, and California bearing ratio, were conducted on expansive soil and expansive soil treated with various percentages of RBI Grade 81. The results indicate that RBI Grade 81 is effective in improving engineering properties of expansive soil.
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Panda, Guru Prasad, Alireza Bahrami, T. Vamsi Nagaraju, and Haytham F. Isleem. "Response of High Swelling Montmorillonite Clays with Aqueous Polymer." Minerals 13, no. 7 (July 13, 2023): 933. http://dx.doi.org/10.3390/min13070933.
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Expansive clays containing mineral montmorillonite exhibit swelling and shrinkage due to variations in the moisture content, leading to significant distresses. There has been a growing interest in chemical and polymer additives treated for high swelling montmorillonite clays in recent years. However, limited attention has been paid to the effect of polyacrylamide on the soil’s swelling behavior. Moreover, nontraditional methods of the soil treatment are applied for the rapid stabilization of soil. In this article, polyacrylamide polymer is used as an additive to expansive clay to control the swelling phenomenon. Three different percentages—2.5%, 5%, and 7.5%—of polymer are blended with oven-dried soil to determine Atterberg limits, compaction features, and swelling characteristics. Additionally, electrical impedance measurement is conducted on treated soil samples with different moisture contents. The electrical resistance of soils and polymer-treated soils is measured based on the electrical resistivity correlation of soils. Tests results for soils stabilized with polyacrylamide show that swelling is significantly reduced with increasing the additive content. Moreover, the addition of polymer improves resistivity of soil. Aqueous polyacrylamide can be utilized as an effective stabilization additive to enhance properties of expansive clays.
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Li, Tianguo, Lingwei Kong, and Bingheng Liu. "The California Bearing Ratio and Pore Structure Characteristics of Weakly Expansive Soil in Frozen Areas." Applied Sciences 10, no. 21 (October 27, 2020): 7576. http://dx.doi.org/10.3390/app10217576.
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The California Bearing Ratio (CBR) of weakly expansive soil is specially relevant to its expansibility. The mechanisms affecting the bearing strength, in terms of the CBR, of weakly expansive soil that could be used as embankments filler are worth studying. In the present study, the effects of compaction energy on the compaction characteristics and CBR value were investigated. Additionally, the pore size distributions of soils with different compaction degrees were studied with nuclear magnetic resonance (NMR), and the effect of freeze–thaw cycles on the pore size distribution of soils with different compaction degrees was considered. Subsequently, the mechanisms influencing the CBR were analyzed at both the macroscale and microscale. A linear relationship between the CBR value and compaction degree was determined, characterizing the gradual variation of expansive soils with different moisture contents. With increasing freeze–thaw cycles, the volume of micropores decreased and mesopores increased, causing the CBR value to decrease. The expansion was a dominant factor for the CBR values. The CBR values rose with an increase in micropores and decreased with an increase in pore volume. It was considered that the tested weakly expansive soil could be used as an embankment filler in frozen areas.
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Adem, Hana, and Sai Vanapalli. "Soil–environment interactions modelling for expansive soils." Environmental Geotechnics 3, no. 3 (June 2016): 178–87. http://dx.doi.org/10.1680/envgeo.13.00089.
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You, Qi Yong. "Numerical Simulation of the Stability of Added Lime Expansive Soils Embankment." Advanced Materials Research 838-841 (November 2013): 821–24. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.821.
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The main reason of expansive soil embankment slope landslide is the infiltration of rainwater. Analyzing engineering characteristics and failure mechanism of expansive soil embankment slope, considering the force of expansion under the infiltration of rainwater, and choosing the appropriate constitutive model, simulate expansive soil embankment slope under humidification state. According different conditions of the expansive soil and different depth of infiltration, and simplifying the swelling force, establish a simple and reasonable model of expansion force changes. Expansive soil embankment slope stability is mainly affected by the moisture of expansive soil slope after analyzing the calculation results. The safety of expansive soil slope after immersion in rainwater decreases significantly. It shows designers should choose reasonable slope ratio and consider the embankment slope protection and drainage measures.
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Ho, David Y. F. "Foundations on expansive soils." Canadian Geotechnical Journal 26, no. 4 (November 1, 1989): 770–71. http://dx.doi.org/10.1139/t89-099.
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Cai, Yi, and Mingxi Ou. "Experimental Study on Expansive Soil Improved by Lignin and Its Derivatives." Sustainability 15, no. 11 (May 29, 2023): 8764. http://dx.doi.org/10.3390/su15118764.
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Expansive soil covers the vast area of Mengzi, Yunnan, China, and creates numerous hazards for construction projects. When treating expansive soil, a modifier is usually added to inhibit its expansion and increase its strength. Lignin and its derivatives can better meet the requirements of expansive soil treatment and have become the preferred choice to replace traditional inorganic modifiers. Lignin is a green and environmentally friendly physical improvement material. In this study, lignin was used to improve soil, alone and combined with its derivatives, and the physical and mechanical properties of the improved soil were studied. Combined with an unconfined compressive strength test, a low-stress direct shear test, and a scanning electron microscopy test, the mechanism of lignin and its derivatives for the improvement of expansive soil is discussed. When calcium lignosulfonate alone was added, the improved soil’s expansion rate decreased, the soil’s water-holding capacity decreased, and its strength increased. Furthermore, the inclusion of 3% calcium lignosulfonate was the best. When the expansive soil was improved with the optimal calcium lignosulfonate content (3% CL) and composite lignin fibers, the strength of the soil body was further improved, the toughness was enhanced, and it shows plastic swelling failure and good water stability. 3% calcium lignosulfonate and 1.5% lignin fiber was the best for composite improvement as; it offered the optimal degree of particle aggregation and the development of pores and cracks was better inhibited, even though the fiber distribution was messy. This study shows that lignin and its derivatives can be used instead of inorganic modifiers to treat expansive soils to reduce the number of inorganic modifiers, and provided a sustainable treatment plan for reducing industrial waste.
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Houston, Sandra L., Heather B. Dye, Claudia E. Zapata, Kenneth D. Walsh, and William N. Houston. "Study of Expansive Soils and Residential Foundations on Expansive Soils in Arizona." Journal of Performance of Constructed Facilities 25, no. 1 (February 2011): 31–44. http://dx.doi.org/10.1061/(asce)cf.1943-5509.0000077.
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Wang, Ming Wu, Shuai Qin, and Peng Hua. "Risk Analysis of Shrink and Expansion for Expansive Soils and Improved Expansive Soils in the Xinqiao Airport Runway of Hefei." Applied Mechanics and Materials 90-93 (September 2011): 1307–12. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1307.
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Risk analysis of shrinking and swelling of expansive soils and improved expansive soils with lime (IESL) for airport runway projection is a complex uncertainty problem. To select the rational foundation treatment plan and ensure the safe operation of runway, herein combined with the features of expansive soils in the runway area of Xinqiao international airport of Hefei, a novel risk analysis method was proposed to classify shrinkage and swell of expansive soils and IESLs by means of coupling set pair analysis with stochastic simulation of triangular fuzzy numbers. A function of six elements connection number was introduced to depict hierarchy and fuzziness of membership between the evaluation sample and the classification standard. Moreover, triangular fuzzy numbers simulated by a stochastic simulation method were presented to specify the component coefficients of discrepancy degree. Then a risk analysis model was described to calculate reliable degree corresponding to a confidence interval. Finally, comparisons of shrinkage and swell for foundation treatment plans of different lime content were conducted. The results will provide basis for the risk design and risk management of runway project on the expansive soils.
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Santhosh, Karakavalasa Sai, and B. Ramesh. "A Systematic Study to Strengthen the Sub Grade of the Pavement by Stabilization of Expansive Soil with Molasses and Jute Fibre." International Journal for Research in Applied Science and Engineering Technology 11, no. 6 (June 30, 2023): 2234–43. http://dx.doi.org/10.22214/ijraset.2023.53897.
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Abstract: Expansive soils, commonly referred to as Black cotton soils (BC), possess undesirable engineering properties such as low bearing capacity and high compressibility. To address these challenges, various stabilizers have been used to enhance the strength of expansive soil, including jute fiber and molasses. This thesis focuses on investigating the effects of incorporating jute fiber as a stabilizer and molasses as an additive to improve the properties of expansive soil. The objectives of this study are to enhance the shear strength of expansive soil by blending jute fiber and molasses mixtures. Jute fibers of different lengths (1cm, 2cm, 3cm, and 4cm) and various percentages (0.5%, 1%, 1.5%, and 2%) are used as stabilizers. Molasses is employed as an additional stabilizer with varying percentages (5%, 8%, 12%, and 15%). Laboratory investigations reveal that the addition of 12% molasses and 1.5% jute fiber significantly reduces the liquid limit, plastic limit, and plasticity index of the expansive soil, while simultaneously increasing the maximum dry density and California Bearing Ratio (CBR). Furthermore, cyclic load test results demonstrate a 62% improvement in the load carrying capacity of the treated expansive soil subgrade flexible pavement compared to untreated expansive soil flexible pavement. Utilizing construction wastes like molasses offers an alternative to reduce road construction costs, especially in rural areas of developing countries. Additionally, jute fiber provides effective reinforcement for expansive soils. These findings highlight the potential of jute fiber and molasses as sustainable and cost-effective stabilizers for enhancing the performance of expansive soils in construction projects
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XU, YONGFU, and SONGYU LIU. "FRACTAL CHARACTER OF GRAIN-SIZE DISTRIBUTION OF EXPANSIVE SOILS." Fractals 07, no. 04 (December 1999): 359–66. http://dx.doi.org/10.1142/s0218348x99000360.
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Fractal mass distribution of expansive soil grains is studied in this paper. It is found that there is different fractal mass distribution exponent of the grain-size distribution for different genesis of expansive soils. The expansiveness, physical properties and mechanical properties of expansive soils can be quantitatively described by the fractal mass distribution exponent of grain-size distribution of expansive soils. In consolidated tests, the fractal mass distribution exponent increases with increases in consolidated pressure, as well as increases in confining pressure in triaxial tests.
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Kalkan, Ekrem, and Necmi Yarba. "The Effects of Pine Tree Sawdust on the Volume Compressibility of Expansive Soils." International journal of Science and Engineering Applications 10, no. 04 (March 23, 2021): 029–33. http://dx.doi.org/10.7753/ijsea1004.1001.
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Expansive soils are very important natural geological materials used in the geotechnical applications in the worldwide. After compacting, they are used as hydraulic barriers in earth structures, such as core of earth fill dams, landfill liners, and etc. However, these soils have some defects from technical points of view. To remove the defects, one of the soil improvement methods is mixing of these soils with granular materials. In this study, pine tree sawdust was used as granular additive material to stabilize the expansive soils. The effects of pine saw dust on the volume compressibility of expansive soils were investigated by using experimental studies under laboratory conditions. The test results showed that the pine saw dust positively affected the geotechnical properties in term of volume compressibility manner. As a consequently, the geotechnical properties of the expansive soil when blended with pine tree sawdust indicates that the pine tree sawdust is a good modification material for this problematic soil.
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ALAlawi, Hilal Salim, Abideen Ganiyu, Morsaleen Chowdhury, and Atef Badr. "Enhancement of Muscat’s Expansive Soil Using Waste Gypsum." Key Engineering Materials 942 (March 24, 2023): 201–11. http://dx.doi.org/10.4028/p-1m8gw2.
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Expansive soils are known to show significant volumetric changes in response to changes in the moisture content. Such soils swell when the moisture content is increased and shrink when the moisture content is decreased, thereby causing distress and damages to structures founded on them. Construction developments on naturally occurring expansive soils are usually problematic. This study examines the properties of expansive soil obtained from the city of Muscat in Oman. The expansive soil samples were further treated with gypsum, which was obtained from waste plasterboards, at varying quantities of 3%, 6%, 9% and 12% by mass in an attempt to stabilize the soil. Based on USCS classification system, the expansive soil was identified a poorly clay with high plasticity (CH) with AASHTO classification of A-6. The pH test confirms the reaction between expansive and gypsum, while both the compaction and unconfined compression strength (UCS) tests revealed the optimum percentage of gypsum required to enhance the properties of expansive soil to be 9% by mass. The unconfined compression strength (UCS) test yielded a 37.7% increase over that of untreated expansive soil at 28 days of curing. The California Bearing Ratio (CBR) test of the treated soil yielded a 57% increase in CBR value for expansive soil treated with 9% of waste gypsum over untreated expansive at the unsoaked state and 70% at soaked state. Overall, a solid understanding of the physical and engineering properties of expansive soil, and the confirmation of the potential use of gypsum for its stabilization, was achieved in this study.
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Onyelowe, Kennedy C., Michael E. Onyia, Diu Nguyen-Thi, Duc Bui Van, Eze Onukwugha, Haci Baykara, Ifeoma I. Obianyo, Lam Dao-Phuc, and Hyginus U. Ugwu. "Swelling Potential of Clayey Soil Modified with Rice Husk Ash Activated by Calcination for Pavement Underlay by Plasticity Index Method (PIM)." Advances in Materials Science and Engineering 2021 (February 12, 2021): 1–10. http://dx.doi.org/10.1155/2021/6688519.
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Volume change in expansive soils is a problem encountered in earth work around the world. This is prominent with hydraulically bound structures or foundations subjected to prolonged moisture exposure. This behavior of clayey used as subgrade, foundation, landfill, or backfill materials causes undesirable structural functionality and failures. To prevent this happening, clayey soils are studied for possible volume change potential and degree of expansion. Consequently, the problematic soils are stabilized. In this work, the stabilization of clayey highly expansive soil classified as A-7-6 soil and highly plastic with high clay content was conducted under laboratory conditions. The treatment exercise was experimented using quicklime-activated rice husk ash (QARHA), hydrated lime-activated rice husk ash (HARHA), and calcite-activated rice husk ash (CARHA) at the rates of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. Upon treatment with the three calcium compounds to produce three sets of treated experimental specimens, the plasticity index was observed and recorded and swelling potentials were evaluated using the plasticity index method (PIM). The results showed a consistent improvement on the properties of the treated soil with the addition of the different activated admixtures. While the utilization of CARHA and HARHA improved the clayey soil to medium expansive soil, the treated clayey soil substantially improved from highly expansive soil with a potential of 23.35% to less expansive with a final potential of 0.59% upon the addition of 10% QARHA. Finally, QARHA was adjudged as the best binding composite due to the highest rate of reduction recorded with its utilization.
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Zhang, Deheng, Fenqiang Xu, Yan Zhang, and Fang Li. "Study on Strength and Deformation Characteristics of Expansive Soils Treated with Lime-biomass Ash." Journal of Solid Waste Technology and Management 47, no. 4 (November 1, 2021): 653–58. http://dx.doi.org/10.5276/jswtm/2021.653.
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This paper investigates the strength deformation of the lime-biomass ash treated expansive soils. The unconfined compressive strength, one-dimensional compression of the modified expansive soil of compaction were studied. The results showed that the maximum dry density and optimum moisture content of expansive soil decreased with the increase of lime and biomass ash content; The unconfined compressive strength test results show that there is no remarkable change in the unconfined compressive strength of the soils immediately treated with biomass ash, but the sample after 7 days of curing period of strength has been greatly improved, especially after the addition of lime is more obvious; the compression coefficient, the rebound coefficient of the saturated expansive soil with lime-biomass ash is significantly smaller than saturated expansive soil. The compressive modulus of the modified expansive soil increases with the increase of vertical pressure, which reflects the hardness of the improved expansive soil.
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Tian, Xuwen, Hongbin Xiao, Zixiang Li, Zhenyu Li, Huanyu Su, and Qianwen Ouyang. "Experimental Study on the Strength Characteristics of Expansive Soils Improved by the MICP Method." Geofluids 2022 (March 25, 2022): 1–10. http://dx.doi.org/10.1155/2022/3089820.
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Microbially induced calcite precipitation (MICP) has been a promising method to improve geotechnical engineering properties; however, there are few literatures about the application of the MICP method to improve the strength characteristics of expansive soils with low permeability. In this paper, a series of CD triaxial tests were carried out to investigate the effect of the MICP method on the strength characteristics of the expansive soils. The results show that the shear strength of the specimens increased with the increase in the cementation solution and eventually reached a stable value. The MICP method can significantly improve the shear strength index of the expansive soils. The cohesion of the expansive soils was increased from 29.52 kPa to 39.41 kPa, and the internal friction angle was increased from 20.13° to 29.58°. The stress-strain curves of expansive soil samples improved by the MICP method show a hyperbolic relationship, which is characterized by strain hardening. The hyperbolic model was chosen to describe the stress-strain relationship of the expansive soils improved by the MICP method, and the predicted results were in good agreement with the measured results. Moreover, we performed a scanning electron microscope (SEM) experiment and revealed the mechanism of the MICP method to improve the strength characteristics of expansive soils. The conclusions above can provide a theoretical basis to further study the strength characteristics of improved expansive soils by the MICP method.
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Zhang, Fuhai, Lei Zhang, and Wangxi Hong. "Stabilization of Expansive Soil with Polyvinyl Alcohol and Potassium Carbonate." Advances in Civil Engineering 2019 (November 14, 2019): 1–11. http://dx.doi.org/10.1155/2019/7032087.
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Expansive soils have great volume change potentials with water content changes, which is problematic to facilities. Great efforts have been spent on finding proper methods to stabilize expansive soils, but these stabilizers all had limitations. The Polyvinyl alcohol (PVA) and K2CO3 combination was proposed in this paper. Free swell tests, oedometric tests, unconfined compression tests, and direct shear tests were performed to investigate the effectiveness of the PVA and K2CO3 combination to control the volume change and increase the soil strength. Microstructures of the natural expansive soil and the stabilized soil were also studied with SEM photos. SEM photos showed a homogenous and dense microstructure after stabilization. In addition, a laboratory soil column model was built to study the ability of this stabilizer combination to stabilize expansive soils by directly spraying the solution on the ground surface. All these test results show that the combination of PVA and K2CO3 is able to effectively stabilize the natural expansive soil and increase the shear strength. It is possible to directly spray the stabilizer solution on the soil surface to form a relatively thick layer of the stabilized expansive soil.
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Samuel, Rinu, Anand J. Puppala, and Miladin Radovic. "Sustainability Benefits Assessment of Metakaolin-Based Geopolymer Treatment of High Plasticity Clay." Sustainability 12, no. 24 (December 15, 2020): 10495. http://dx.doi.org/10.3390/su122410495.
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Expansive soils are prevalent world over and cause significant hazards and monetary losses due to infrastructure damages caused by their swelling and shrinking behavior. Expansive soils have been conventionally treated using chemical additives such as lime and cement, which are known to significantly improve their strength and volume-change properties. The production of lime and cement is one of the highest contributors of greenhouse gas emissions worldwide, because of their energy-intensive manufacturing processes. Hence, there is a pressing need for sustainable alternative chemical binders. Geopolymers are a relatively new class of aluminosilicate polymers that can be synthesized from industrial by-products at ambient temperatures. Geopolymer-treated soils are known to have comparable strength and stiffness characteristics of lime and cement-treated soils. This study evaluates the sustainability benefits of a metakaolin-based geopolymer treatment for an expansive soil and compares its results with lime treatment. Test results have shown that geopolymers have significantly improved strength, stiffness, and volume-change properties of expansive soils. Increased dosages and curing periods have resulted in further property enhancements. Swell and shrinkage studies also indicated reductions in these strains when compared to control conditions. The sustainability benefits of both geopolymer and lime treatment methods are evaluated using a framework that incorporates resource consumption, environmental, and socio-economic concerns. This study demonstrates geopolymer treatment of expansive soils as a more sustainable alternative for expansive soil treatments, primarily due to metakaolin source material. Overall results indicated that geopolymers can be viable additives or co-additives for chemical stabilization of problematic expansive soils.
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Devkota, Bikash, Md Rajibul Karim, Md Mizanur Rahman, and Hoang Bao Khoi Nguyen. "Accounting for Expansive Soil Movement in Geotechnical Design—A State-of-the-Art Review." Sustainability 14, no. 23 (November 24, 2022): 15662. http://dx.doi.org/10.3390/su142315662.
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Lightweight structures built on expansive soils are susceptible to damage caused by soil movement. Financial losses resulting from the improper design of structures on expansive soils can be significant. The interactions and failure mechanisms of different geotechnical structures constructed on such soils differ depending on the structure type, site characteristics, and climatic conditions, as the behaviour of expansive soils is influenced by moisture variations. Therefore, the performance of different geotechnical structures (e.g., lightweight footings for residential buildings) is expected to be adversely affected by climate change (especially rainfall and temperature change), as geotechnical structures are often designed to have a service life of 50–100 years. Some structures may even fail if the effect of climate change is not considered in the present design. This review aims to provide insights into problems associated with expansive soils that trigger the failure of lightweight structures, including current investigations and industry practices. This review recognises that although the soil moisture conditions govern expansive soil behaviour, limited studies have incorporated the effect of future climate changes. In addition, this review identifies the need to improve the current Australian design practice for residential footings through the inclusion of more site-specific investigations and expected climate changes.
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Li, Jie, and An Nan Zhou. "The Australian Approach to Residential Footing Design on Expansive Soils." Applied Mechanics and Materials 438-439 (October 2013): 593–98. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.593.
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Expansive soils in semi-arid regions are of great concern to design and geotechnical engineers. Damage to residential buildings resulting from expansive soil movements has been widely reported in Australia. This paper describes the current practice in Australia, which includes the site classification, laboratory tests and residential footing design. A case study of a residential house damaged by expansive soils is also presented.
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Bekkouche, Souhila Rehab, Mohammed Benzerara, Umar Zada, Ghulam Muhammad, and Zulfiqar Ali. "Use of Eco-Friendly Materials in the Stabilization of Expansive Soils." Buildings 12, no. 10 (October 21, 2022): 1770. http://dx.doi.org/10.3390/buildings12101770.
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Volume change of expansive soils is a challenging issue, which affects various engineering structures all over the world. Consequently, we need environmentally-friendly and cost-effective soil stabilizers to address the challenges related to expansive soils. The utilization of natural fibers allows for the reduction in environmental impact since they are renewable and biodegradable raw materials. Moreover, the current article presents an experimental approach to study the effect of natural fibers on the mechanical behavior of expansive soils. Various experimental tests—such as Atterberg limits, standard compaction, direct shear, swelling potential, and swelling pressure—were conducted on control and treated soil samples using different percentages of fibers. The results of measurements of the physico-mechanical properties after reinforcement of the soil with 1%, 5%, and 10% of natural fibers indicate that the mechanical behavior of expansive soils is greatly influenced by the addition of natural fibers. To conclude, 86% reduction was observed in the swelling coefficient of treated soil. Future research can be done to check the durability of the current practice in detail.
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Xiao, Hong Bin, Cong He, Zhen Yu Li, and Guo Xiao. "Identification of Creep Model and Parameters Inverse Analysis for Nanning Expansive Soils." Advanced Materials Research 639-640 (January 2013): 657–64. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.657.
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A series of loading - unloading consolidation creep experiments had been carried out on Nanning unsaturated expansive soils. Lots of loading - unloading creep curves under different stress levels were obtained. Through the various stages of creep deformation analyzed, it was concluded that the creep deformation of expansive soil contained elastic deformation, viscoelastic deformation and plastic deformation of components. Then model components in constitutive model of expansive soils were discussed. The rheological model of the seven components was proposed, which can describe unsaturated expansive soil elastic - viscous - plastic behavior. According to the experimental datum, all parameters of this model under different stresses were determined by the inverse analysis method. It is showed that the values of numerical calculated using this model agree well with those obtained by the creep tests. The conclusions provide a reliable theoretical basis for the rheological model of expansive soils to further study.
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Puppala, Anand J., Koonnamas Punthutaecha, and Sai K. Vanapalli. "Soil-Water Characteristic Curves of Stabilized Expansive Soils." Journal of Geotechnical and Geoenvironmental Engineering 132, no. 6 (June 2006): 736–51. http://dx.doi.org/10.1061/(asce)1090-0241(2006)132:6(736).
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Abdulla, Rozan, and Nadhmiah Majeed. "Enhancing Engineering Properties of Expansive Soil Using Marble Waste Powder." Iraqi Geological Journal 54, no. 1E (May 31, 2021): 43–53. http://dx.doi.org/10.46717/igj.54.1e.4ms-2021-05-25.
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Owing to its propensity to swell when in contact with water, expansive soil causes severe structural problems and shrinks when they dry out. Soil stabilization is a well-known method used to enhance the soil's physical and engineering properties and is commonly adopted for improving soil structures. The mechanical stabilization of different soils is evaluated by adding varying proportions of marble dust (10, 20, 30 percent) of Penjwen, Said Sadiq and Pirmam marble waste powder) to expansive soil. Shear strength and consolidation parameters, such as void ratio, compression index, and sample swelling index, were determined as basic properties. The marble dust is obtained from the cutting and grinding of real marble from the Erbil marble factory in the experimental program. The addition of marble dust decreases the swelling percentage, with an increase in the percentage of marble powder in swelling soils. It is concluded that the swelling in Bastora soil is more than that of Erbil Airport soil, based on the swelling index studies.
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Mehta, Aashish A., and pranay maidamwar. "Numerical Modelling for effect of rainfall on unsaturated soil slopes." IOP Conference Series: Earth and Environmental Science 1193, no. 1 (June 1, 2023): 012013. http://dx.doi.org/10.1088/1755-1315/1193/1/012013.
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Abstract Expansive soils are predominant in many parts of the world. Expansive soil treated as problematic soils, as economic and design a safe slope on expansive soils is major challenge for civil engineers. Expansive soils were compacted under unsaturated condition, in various construction projects. Major failures reported in many countries around the world are due to swell shrinkage characteristics causing unstable slopes. Fills and compacted soils have an inherent suction when they are first compacted. The suction is the most important factor which affects the shear strength of unsaturated soil. variation of suction in unsaturated soil is an important factor considered for solving issues like slope stability and bearing capacity failure in unsaturated soil. Rainwater infiltration are major triggering factor for failureof expansive soil slopes. The strength of unsaturated soil changes with water evaporation and infiltration. Due to infiltration of rainwater into the soil a significant change in the pore water takes place. Hence, this fluctuation in pore water pressure responsible for the distinct mechanical behavior of unsaturated soil under different Geotechnical problems. A numerical modeling was done with Plaxis LE software, considering parameters of unsaturated soil. As the changes in pore-water pressure and moisture content are a function of the flow of moisture through the soil-atmosphere boundary.The effect of soil type, rainfall intensity, location of ground water table, permeability functionsareconsidered to reproduce the soil-atmosphere interaction. Obtain results illustrates the combine effect of suction and increase of saturation due to rainfall on slopes. It was observed that rainfall increase the induced matric suction and increase the positive pore water pressure finally results in slope failures.
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Zamin, Bakht, Hassan Nasir, Khalid Mehmood, Qaiser Iqbal, M. Tariq Bashir, and Asim Farooq. "Development of Some Novel Suction-Based Correlations for Swell Behavior of Expansive Soils." Advances in Civil Engineering 2021 (November 30, 2021): 1–13. http://dx.doi.org/10.1155/2021/4825593.
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Swelling and shrinkage are the two distinctive characteristics of expansive soils, and due to this behavior, these soils are considered a natural hazard for infrastructure. Many structures in different regions have been impaired due to the swell/shrink behavior of the expansive soil. Most of the severe distress is impeded because of the inherent suction (negative pore water pressure) present in expansive soils. Both suction and swelling parameters are greatly affected by the surrounding moisture content. Due to this feature of expansive soil, geotechnical engineers are interested in utilizing the suction-based correlations for the assessment of unsaturated expansive soils. The current investigation was carried out to develop novel correlations incorporating lab testing and field instrumentation. To fulfill the objectives, eight sites of the local expansive soil in Pakistan were selected for samples collection and field testing. Conventional odometer testing was conducted to measure the swell pressure (Sp) and swell potential (S) of the fabricated/remolded specimens. Gypsum block (G-block) sensors were additionally utilized for estimating the matric suction in the field. To expand the database, the previously published data of the same nature was also incorporated. Based on the results, the power form of the novel correlations (suction-based) is highly significant for estimating (Sp), while for swell potential, the logarithmic correlation with R2 = 0.6551 is more significant than other forms of correlations. The proposed suction-based correlation can be equally utilized for the estimation of field suction as well as for swell behavior of expansive soil having a plasticity index (PI) ≥ 22%.
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Puppala, Anand J., and Chisha Musenda. "Effects of Fiber Reinforcement on Strength and Volume Change in Expansive Soils." Transportation Research Record: Journal of the Transportation Research Board 1736, no. 1 (January 2000): 134–40. http://dx.doi.org/10.3141/1736-17.
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The results of a research study to investigate the influence of discrete and randomly oriented polypropylene fiber reinforcement on expansive soil stabilization are presented. Two expansive soils were used as control soils in the testing program. Two types of fibers and four fiber dosages (0,0.3,0.6, and 0.9 percent by dry weight of soil) were considered. Both raw and fiber-reinforced clayey samples were prepared and subjected to unconfined compressive strength (UCS), volumetric shrinkage, three-dimensional free swell, and swell pressure tests. Test results were statistically analyzed to investigate the effectiveness of fiber reinforcement on strength, swell, and shrinkage characteristics of expansive clays. Results indicated that the fiber reinforcement enhanced the UCS of the soil and reduced both volumetric shrinkage strains and swell pressures of the expansive clays. The fiber treatment also increased the free swell potential of the soils. Practical implications of the findings and future research directions are discussed.
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Zamin, Bakht, Hassan Nasir, Khalid Mehmood, Qaiser Iqbal, Asim Farooq, and Mohammad Tufail. "An Experimental Study on the Geotechnical, Mineralogical, and Swelling Behavior of KPK Expansive Soils." Advances in Civil Engineering 2021 (July 8, 2021): 1–13. http://dx.doi.org/10.1155/2021/8493091.
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Expansive soils are found in numerous regions of the world explicitly in arid and semiarid zones. These soils expand when absorbed moisture and shrink when released water. Such soil is viewed as a characteristic risk for infrastructures due to the shrink and swell behavior. These soils become more problematic when lightly or moderately loaded structures are built on them. The swelling and shrinkage in these soils chiefly happen due to the presence of montmorillonite minerals. The mineralogical and swell behavior of foundation soils is playing a vital role in the overall stability of a structure. These parameters are often ignored in the geotechnical report writing stage specifically in small projects, due to which, the durability and service life of the facilities are reduced and the maintenance cost is increased. To mitigate the potential damages in structures constructed on expansive soil, it is necessary to assess the mineralogical and swelling characteristics of expansive soil. The current study aims to determine the geotechnical, mineralogical, and swell behavior of the local expansive soils. Based on the results, the Karak soil has the highest plasticity index (PI) of 37% with a clay fraction of 28%, while the D.I. Khan soil has the least PI of 23% with a clay fraction of 17%. Similarly, Karak’s soil contained a higher percentage of montmorillonite (Rp = 8.9%). The maximum values of swell pressure, swell potential, and 1D deformation are 280 kPa, 12.5%, and 1.92 mm for the Karak soil, 6.45% 150 kPa, and 1.38 mm for D.I. Khan soil, and 10.5%, 245 kPa, and 1.64 mm for Kohat soil, respectively. This concludes that Karak’s soil has high plasticity and swell characteristics than Kohat and D.I. Khan soil. The swell characteristic of expansive soils increases with the increase in the percentage of the fine specifically the clay fraction. Furthermore, the Karak soil is more critical than Kohat and D.I. khan soil for lightly loaded structures.
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He, Shi, Xinbao Yu, Aritra Banerjee, and Anand J. Puppala. "Expansive Soil Treatment with Liquid Ionic Soil Stabilizer." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 52 (August 23, 2018): 185–94. http://dx.doi.org/10.1177/0361198118792996.
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Calcium-based stabilizers such as lime and cement control swell and shrinkage behavior and enhance strength properties for expansive soils through the formation of pozzolanic components. However, sulfate-bearing subgrade soils stabilized with calcium-based stabilizers might cause excessive swelling and shrinkage due to the formation of highly expansive minerals like ettringite and thaumasite. In this paper, one liquid ionic soil stabilizer (LISS) was evaluated as an alternative stabilizer used to control swelling and shrinkage behavior of expansive soils. A comprehensive laboratory experiment program including a linear shrinkage test, a one-dimensional swell test, and an unconfined compressive strength test, was designed and carried out on soils from Dallas, Texas before and after treatment. Three dosage levels of stabilizer and four different curing periods were investigated. Test results indicate that LISS is an effective stabilizing agent, which not only reduces swelling and soil plasticity but also increases soil strength. Furthermore, a similar type of LISS is utilized to treat the soil in Dallas via deep injection using a hydraulic pump. Field emission scanning electron microscopy results on the test soil showed that the stabilizing program is likely to work through clay flocculation and morphological variations in the clay particles.
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Tu, Hongyu, and Sai K. Vanapalli. "Prediction of the variation of swelling pressure and one-dimensional heave of expansive soils with respect to suction using the soil-water retention curve as a tool." Canadian Geotechnical Journal 53, no. 8 (August 2016): 1213–34. http://dx.doi.org/10.1139/cgj-2015-0222.
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The one-dimensional (1-D) potential heave (or swell strain) of expansive soil is conventionally estimated using the swelling pressure and swelling index values that are determined from different types of oedometer test results. The swelling pressure of expansive soils is typically measured at saturated condition from oedometer tests. The experimental procedures of oedometer tests are cumbersome as well as time-consuming for use in conventional geotechnical engineering practice and are not capable of estimating heave under different stages of unsaturated conditions. To alleviate these limitations, semi-empirical models are proposed to predict the variation of swelling pressure of both compacted and natural expansive soils with respect to soil suction using the soil-water retention curve (SWRC) as a tool. An empirical relationship is also suggested for estimating the swelling index from plasticity index values, alleviating the need for conducting oedometer tests. The predicted swelling pressure and estimated swelling index are then used to estimate the variation of 1-D heave with respect to suction for expansive soils by modifying Fredlund’s 1983 equation. The proposed approach is validated for eight field sites from six countries — namely, Saudi Arabia, Australia, Canada, China, USA, and UK — and on six different compacted expansive soils from USA.
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Sridharan, A., and K. Prakash. "Classification procedures for expansive soils." Proceedings of the Institution of Civil Engineers - Geotechnical Engineering 143, no. 4 (October 2000): 235–40. http://dx.doi.org/10.1680/geng.2000.143.4.235.
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Al-Rawas, Amer Ali, and A. McGown. "Microstructure of Omani expansive soils." Canadian Geotechnical Journal 36, no. 2 (September 25, 1999): 272–90. http://dx.doi.org/10.1139/t98-111.
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The fundamental factors controlling the expansive nature of Omani soils are their characteristics with respect to geology, mineralogy, engineering, and microstructure. The first three factors have been extensively studied, however, the fourth has not yet been fully investigated and no work has been published on this aspect. Therefore, this paper deals with the microstructure characteristics of these soils. The scanning electron microscope was employed in this investigation. Three samples selected from different sites where expansive soils problems were known (Al-Khod, Al-Murtafa'a, and Duqm) were investigated. Two specimens from each sample, representing the vertical and horizontal planes, were tested. In addition, two samples that were subjected to swelling were tested to investigate the microfabric changes caused by swelling. The fabric of the Omani expansive soils studied generally consists of dense clay matrices, although clay-granular matrices are occasionally observed. In addition, no connectors have been observed and only few aggregations have been seen. Pore spaces are mainly of the intra-assemblage and intra-elemental types. Significant microfabric changes were induced by swelling.Key words: microstructure, microfabric, SEM, expansive soils, Oman, clay minerals.
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Nagaraj, H., M. Munnas, and A. Sridharan. "Swelling behavior of expansive soils." International Journal of Geotechnical Engineering 4, no. 1 (January 2010): 99–110. http://dx.doi.org/10.3328/ijge.2010.04.01.99-110.
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Al-Gharbawi, Ahmed S. A., Ahmed M. Najemalden, and Mohammed Y. Fattah. "Expansive Soil Stabilization with Lime, Cement, and Silica Fume." Applied Sciences 13, no. 1 (December 29, 2022): 436. http://dx.doi.org/10.3390/app13010436.
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The type of soil known as expansive soil is capable of changing its volume through swelling and contracting. These types of soils are mostly composed of montmorillonite, a mineral with the capacity to absorb water, which causes the soil to heave by increasing its volume. Due to their capacity to contract or expand in response to seasonal fluctuations in the water content, these expansive soils might prove to be a significant risk to engineering structures. Many studies have dealt with swelling soils and investigated the behavior of these soils, as well as their improvement. In this study, three percentages of lime, cement, and silica fume (5, 7, 9%) are used to stabilize the expansive soil, and the work is divided into two sections: the first is using a consolidation test to record the free swell and swell pressure for the untreated and treated soils; in the second part, the grouting technique is utilized as a process that can be applied in the field to maintain the improvement in the bearing capacity. It is concluded that the soil stabilized with different percentages of lime, cement, and silica fume exhibits a decrease in both free swell and swelling pressure by approximately 65% and 76%, respectively, as compared with untreated soil. The soil grouted with silica fume increases the bearing capacity of footings resting on the grouted soil by approximately 64% to 82% for the soil treated with 5% and 9% silica fume, respectively, as compared with untreated soil.
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Han, Shaoyang, Baotian Wang, Marte Gutierrez, Yibo Shan, and Yijiang Zhang. "Laboratory Study on Improvement of Expansive Soil by Chemically Induced Calcium Carbonate Precipitation." Materials 14, no. 12 (June 18, 2021): 3372. http://dx.doi.org/10.3390/ma14123372.
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This paper proposes the use of calcium carbonate (CaCO3) precipitation induced by the addition of calcium chloride (CaCl2) and sodium carbonate (Na2CO3) solutions as a procedure to stabilize and improve expansive soil. A set of laboratory tests, including the free swell test, unloaded swelling ratio test, unconfined compression test, direct shear test, scanning electron microscopy (SEM) test, cyclic wetting–drying test and laboratory-scale precipitation model test, were performed under various curing periods to evaluate the performance of the CaCO3 stabilization. It is concluded from the free swell tests and unloaded swelling ratio tests that the addition of CaCl2 and Na2CO3 can profoundly decrease soil expansion potential. The reduction in expansion parameters is primarily attributed to the strong short-term reactions between clay and stabilizers. In addition, the formed cementation precipitation can decrease the water adsorption capacity of the clay surface and then consequently reduce the expansion potential. The results of unconfined compression tests and direct shear strength tests indicated that the addition of CaCl2 and Na2CO3 has a major effect on geotechnical behavior of expansive soils. Based on the SEM analyses, new cementing crystalline phases formatted by sequentially mixing CaCl2 and Na2CO3 solutions into expansive soil were found to appear in the pore space, which results in a much denser microstructure. A laboratory-scale model test was conducted, and results demonstrate the effectiveness of the CaCO3 precipitation technique in stabilizing the expansive soil procedure. The test results indicated that the concentration of CaCl2 higher than 22.0% and Na2CO3 higher than 21.2% are needed to satisfactorily stabilize expansive soil. It is proposed to implement the precipitation technique in the field by the sequential permeation of CaCl2 and Na2CO3 solutions into soils in situ.