Peat soil is a soft material from the group of organic soils. This soil has different behavioral characteristics than other nonorganic soils. One of its weaknesses is insufficient shear strength. Therefore, any construction and loading on it require special measures such as reinforcement. The present study aims to experimentally investigate the shear behavior of peat soil reinforced with geotextiles. In this research, first undisturbed samples of the Urmia peat soil were collected from in situ road construction site of Urmia to Tabriz. After determining its initial physical characteristics, direct shear tests under vertical stresses of 10, 20, and 30 kPa with changing strain rate of 0.9 mm/min and 0.1 mm/min were conducted on two types of peat soils with average organic material content of 33% and 72%, respectively. In the second part, direct shear test was performed between peat samples and two types of geotextiles with tensile strengths of 30 and 6 kN/m. The results showed that the percentage of organic materials in peat plays a significant role in its friction angle (φ), and the peat with higher rate of organic materials has higher frictional behavior and less cohesion (c). Also, the application of geotextile, depending on its tensile strength and the amount of organic materials in the peats, has different results in increasing the peat friction angle. The test results show with higher amount of organic materials in peat and the greater tensile strength of the geotextile; frictional resistance between peat and geotextile may be greater than in peat alone.

Reinforced concrete walls are one of the most efficient and earthquake-resistant systems. In order to provide adequate performance against seismic forces, their ductility should be provided by considering some design principles. Since confining the concrete increases the ductility of the reinforced concrete members, design instructions try to increase the ductility of the wall by utilizing transverse rebars in a certain length of wall edges. In this study, the need for the transverse steel bars to apply confinement in concrete is compared with the equations suggested by previous studies for the displacement-based design of structural bearing walls. For this purpose, nonlinear static analysis and time history analysis was utilized. The results of the study indicate that the lateral deformation of the structural bearing walls is less than the final limit specified by the design codes, even without considering the transverse steel bars for concrete confinement.

Contamination of soil and underground waters is a common environmental problem. Arsenic is a toxic chemical used widely in chemical industrial applications. New methods such as solidification/stabilization developed as requiring much space and propagation of materials in primary treatment methods caused interim methods for disposal of contamination to become inappropriate. The aim of this study was to investigate the use of cement kiln dust (CKD) and lime dust in solidification/stabilization process for arsenic-contaminated soils. Laboratory-prepared samples spiked with arsenic were made and treated with CKD and lime dust ranging from 15 to 30 wt% and 5–15 wt%, respectively. The effectiveness of treatment was evaluated at 28 days of curing based on the solidification/stabilization tests including unconfined compression test, toxicity characteristic leaching procedures (TCLP), and scanning electron microscopy (SEM). The results show that, though lime dust has a minor effect on samples strength, it has a significant effect on arsenic sorption. On the other hand, CKD causes immobilization of arsenic in the soil, as well as a major effect on soil strength. Based on the results, samples with 20 wt% CKD and 5 wt% lime dust have the optimized correlation between strength and acceptable level of Arsenic leakage in the TCLP test.