Investigation of tensile strength and deformation characteristics of Varamin collapsible soils at undisturbed, reconstituted and treated states

Document Type : Original Article

Authors

1 Department of Geology, University of Isfahan

2 Professor, Department of Engineering Geology, Isfahan University

Abstract

Tensile failures including tensile cracks on the upper part of instable slopes, earth fissures, tensile cracks in earth dams, and any kind of tensile failures resulted from tensile stresses within soil body are considered as important engineering geological features. Studying tensile strength and deformation characteristics of soils can have a great role in the prevention of adverse phenomena resulted from tensile failures in soils. The Varamin collapsible soils are subjected to tensile fractures and earth fissuring because of the tensile stresses raised from the land subsidence of the Varamin plain. Therefore, in this study, the strength and deformation characteristics of these soils were investigated at undisturbed, reconstituted and treated states. Results indicate that, when undisturbed collapsible soils are subjected to tensile stresses, they show a low tensile strength and behave brittle in tension. Reconstituted soils have a lower tensile strength in comparison with undisturbed soils and behave very soft and fail easily in tension. Treated soils have a higher tensile strength in comparison with undisturbed soils and behave more ductile in tension and tolerate more deformation before tensile failure. Results indicate that the treatment of the collapsible soils with stabilizer materials together with compaction is an efficient method for strengthening these soils against tensile stresses and for improving their performance in tension.

Keywords

Main Subjects


حافظی مقدس، ن.، نیکودل، م. ر.، بهرامی، ک.، 1390. ارزیابی قابلیت رمبندگی خاک های لسی حوزه قرناوه در شمال کلاله، استان گلستان، مجله انجمن زمین­شناسی مهندسی ایران، جلد چهارم، شماره 1 و 2، 46-39.
رضایی، ح.،  لشکری پور، غ.، رهنما راد، ج.، پیرانداخ ر.، 1390. ارزیابی لس­های استان گلستان بر اساس معیارهای زمین شناسی مهندسی، فصلنامه زمین شناسی کاربردی، شماره یک، 40-29.
فریدونی، د.، 1390. مروری بر ویژگیهای ژئوتکنیکی خاکهای رمبنده و بررسی پراکندگی آنها در ایران. هفتمین کنفرانس زمین شناسی مهندسی و محیط زیست ایران دانشگاه صنعتی شاهرود، شاهرود.
کمک پناه، ع.، 1386. مطالعه علل پدیده گسیختگی زمین در جادههای دشت یزد – اردکان، پژوهشنامه حمل و نقل، سال چهارم، شماره دوم، 196-181.
معروف، م. ع.، بلوری بزاز، ج.، 1393. اصلاح و به­سازی خاک­های رمبنده. نشریه زمین شناسی مهندسی، جلد هشتم، شماره 4، 2533-2513.
ASTM.,  2007. Standard test methods for laboratory compaction characteristics of soil using standard effort, D698.
ASTM., 2007. Standard test method for unconfined compressive strength of cohesive soil, D2166.
Avsar, E., Ulusay, R., Aydan, O., Mutluturk, M., 2016. On the difficulties of geotechnical sampling and practical estimates of the strength of a weakly bonded volcanic soil, Bulletin of Engineering Geology and the Environment, 74: 1375-1394.
Cui, H., Jin, Z., Bao X., Tang, W., Dong, B., 2018. Effect of carbon fiber and nanosilica on shear properties of silty soil and the mechanisms, Construction and Building Materials, 189: 286-295.
Goulding, R. B., 2006. Tensile strength, shear strength, and effective stress for unsaturated sand. Ph.D. dissertation, University of Missouri – Columbia.
He, S., Bai, H., Xu, Z., 2018. Evaluation on Tensile Behavior Characteristics of Undisturbed Loess, Energies, 11: 1974.
Kafodya, I., Okonta, F., 2018a. Effects of natural fiber inclusions and pre-compression on the strength properties of lime-fly ash stabilised soil, Construction and Building Materials, 170: 737-746.
Kafodya, I., Okonta, F., 2018b. Density control method for compression test of compacted lime-flyash stabilised fiber-soil mixtures, MethodsX, 5: 848-856.
Kim, T., Kim, T., Kang, C., Ge, L., 2012. Factors influencing crack-induced tensile strength of compacted soil, Journal of materials in civil engineering (ASCE), 24(3): 315-320.
Li, Y., 2018. A review of shear and tensile strengths of the Malan Loess in China, Engineering Geology, 236:4-10.
Li, P., Vanapalli, S., Li, T., 2016. Review of collapse triggering mechanism of collapsible soils due to wetting, Journal of Rock Mechanics and Geotechnical Engineering, 8: 256-274.
Lu, N., Wu, B., Tan, C., 2007. Tensile strength characteristics of unsaturated sands, Journal of geotechnical and geoenvironmental engineering (ASCE), 133: 144-154.
Luo, H., Wu, F., Chang, J., Xu, J., 2018. Microstructural constraints on geotechnical properties of Malan Loess: A case study from Zhaojiaan landslide in Shaanxi province, China, Engineering Geology, 236: 60-69.
Nikbakhti, O., Hashemi, M., Banikheir, M.,  Khabbazi Basmenj, M., 2018. Geoenvironmental assessment of the formation and expansion of earth fissures as geological hazards along the route of the Haram-to-Haram Highway, Iran, Bulletin of Engineering Geology and the Environment, 77: 1421-1438.
Peng, J., Wang, S., Wang, Q., Zhuang, J., Huang, W., Zhu, X., Leng, Y., Ma, P., 2019. Distribution and genetic types of loess landslides in China, Journal of Asian Earth Sciences, 170: 329-350.
Sun, P., Peng, J., Chen, L., Yin, Y., Wu, S., 2009. Weak tensile characteristics of loess in China — An important reason for ground fissures, Engineering Geology, 108: 153-159.
Sun, P., Peng, J., Chen, L., Lu, Q., Igwe, O., 2016. An experimental study of the mechanical characteristics of fractured loess in western China, Bulletin of Engineering Geology and the Environment, 75(4): 1639-1647.
Tran, K. Q.,  Satomi, T.,  Takahashi, H., 2018. Improvement of mechanical behavior of cemented soil reinforced with waste cornsilk fibers, Construction and Building Materials, 178: 204-210.
Vanicek, I., 2013. The importance of tensile strength in geotechnical engineering, Acta Geotechnica Slovenica, 1: 5-17.
Wang, J., Li, P., Gu, Q., Xu, Y., Gu, T., 2019. Changes in tensile strength and microstructure of loess due to vibration, Journal of Asian Earth Sciences, 169: 298-307.
Xu, J., Meng, L., An, H., Wang, L., 2015. The bending mechanism of Anping ground fissure in the Hebei Plain, North China, Environmental Earth Sciences, 74(9): 6859-6870.
Xu, L., Coop, M. R., Zhang, M., Wang, G., 2018. The mechanics of a saturated silty loess and implications for landslides, Engineering Geology, 236: 29-42.
Zomorodian, S. M. A., Moghispour, S., Soleymani, A., O'Kelly, B. C., 2017. Strength enhancement of clean and kerosene-contaminated sandy lean clay using nanoclay and nanosilica as additives, Applied Clay Science, 140: 140-147.