Journal of Engineering Geology

Effect of Glycerol and Acetone on the physical and mechanical properties of a clay soil

In this research work the effect of glycerol and acetone on the properties of a clay soil with low plasticity (CL) was studied through experimental tests. Contaminated soil was prepared by mixing 10, 15 and 20% pure glycerol or acetone with soil. A set of experimental tests including Atterberg limits, compaction, free swelling, Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), consolidation tests and Scanning Electron Microscopy (SEM) were conducted on uncontaminated and contaminated soil. The results showed that the effect of glycerol on contaminated soil was a reduction of Atterberg Limits, Free Swelling, optimum water content and increasing maximum dry unit weight but the effect of acetone was in the opposite trend of glycerol. These variations in the behaviors of soil were the function of percent of glycerol or acetone. In addition, the results indicated that both glycerol and acetone cause the reduction in the values of compressive strength and CBR number of soil but the reduction due to glycerol was more than the acetone. The results of consolidation test showed that the values of compression index (Cc) and swelling index (Cs) were independent of the percent of chemical fluids. The SEM results also reveal that these two contaminations cause some variations in the physical and mechanical properties of a clay soil becase of changing the structure of soil and the effect of these contaminations on the properties of soil was not the same.

Key words: hydrocarbon contamination, Atterberg limits, free swelling, Unconfined Compressive Strength (UCS), CBR and consolidation test.

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Investigation of the effect of Bentonite and Seryshum on the resistance parameters of fine dust-producing soils in Varamin region

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Evaluation and estimation of durability of sedimentary rocks in Sheikhan Valley (northwest of Khorramabad) against salt weathering

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Investigation of the effect of mineralogy in strenghth of schist rocks in Mouteh gold mine

In this study, due to the landslide in schist rocks, in the wall of Mouteh gold mines, including of the eastern wall of ChahKhatoon mine, it is important to identify the effective factors. Therefore, due to the diversity of schists in Chah Khatoon and Sanjadeh gold mines (two active mines in Mouteh Complex), to survey the mineralogy of schist rocks in Moteh gold mine has been done by identifying important factors in changes in rock strength. Cosequently, 10 schist samples from walls of these mines were considered for mineralogical, XRD studies. In the next step, these schists were subjected to uniaxial compressive strength (UCS) and Brazilian tests to estimate the mechanical properties and quality of rock mass in different zones of mineral walls. The results showed that the UCS and Brazilian index in these schists are directly and inversely related to the SiO₂and Al₂O₃ contents of the rocks, respectively, as well as the secondary structures.Some factors such as the presence of secondary structures, continuous surface area, particle size, and mineralogical composition play an important role in the failure modes of these rocks. UCS and Brazilian strength of schists vary from 10 MPa to 72 MPa and 1.9 to 10.2 MPa, respectively. The lowest UCS occurs in strongly weathered rocks with low silica content. However, the type of clay minerals is effective in the stability of the mineral wall. Considering the presence of montmorillonite clay mineral in the eastern wall of Chahkhatoun mine, the rock resistance is moderate despite the high percentage of silica. UCS values of wet and dry rock samples containing muscovite and montmorillonite clay minerals were more different from those of other rocks. In this regard, the rocks with Illite clay minerals are more resistant than Smectite and montmorillonite minerals. In general, the resistance of schists depends on various factors such as mineralogy, which is of great importance because of its involvement in the formation of secondary structures.

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Effects of unreinforced /reinforced sand layers coupled with / without sand columns on bearing capacity – settlement of soft clay

Mahmood Reza Abdi

In current paper the effects of surface unreinforced / reinforced sand layers coupled with and without single and group sand columns on the bearing capacity – settlement behavior of soft clays has been investigated. In this regard behavior of soft clay, clay + unreinforced / reinforced sand layer, clay + single / group sand piles and clay + unreinforced / reinforced sand layer + single / group piles samples has been assessed. Geogrid was adopted as the reinforcement, a circular plate 5cm in diameter as the loading surface and C.B.R. apparatus as the loading system. Results show that employing unreinforced / reinforced sand layers at a settlement ratio of 5% improves bearing capacity by 4 t0 7 times the soft clay. Coupling the surface unreinforced / reinforced sand layers with single / group sand piles further increases the bearing capacity by 7 to 9 times that of soft clay.

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Study of Nano-clay and Limestone Powder Effects on the Geotechnical Properties of Clayey Soil of Eastern Tabriz

Clayey soils in terms of sharp reduction in strength and swelling ability as a results of water and moisture absorption, it is considered as one of the most problematic soils in civil engineering and construction works. Nowadays, Nano materials such as Nano clay are used to improve and stabilize of clay. On the other side, the increasing volume of municipal waste and residues materials especially debris of building destruction have caused many problems in mega cities such as environmental issues due to incorrect disposal of waste material. Main propose of this research is study of possibility in effecting Nano clay and limestone powder mixture for improve geotechnical properties of Kuye Nasr clayey soil in Tabriz City. In this study, Nano clay and limestone powder in both separate and combined conditions with 5 and 10 percentage are mixed with clay. Curing of stabilized specimens have been performed in 7, 14 and 28 days. For evaluating geotechnical behavior of mixture materials some tests were performed such as Atterberg limits, Compaction, uniaxial strength and direct shear (in 1, 2 and 3 kg/cm2 vertical stress). Results show that the simultaneous effects of 5% Nano clay with 10% limestone powder with 7 days curing period in ambient temperature conditions in clay reduced plasticity index by 72%, improved graining skeleton structure, reduced void ratio of inter grains and increased shear strength by 33%.

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