Mohammad Hossin Bazyar, Mostafa Ebrahimi, Mehdi Zamani Lenjani, Masood Makarchian,
Volume 11, Issue 3 (Vol. 11 No. 3 Autumn 2017 2018)
Abstract
Geotechnical engineers, in many cases face with low strength or high swelling potential of clayey soils. Stabilization methods are used to improve the mechanical properties of this type of soils. Lime and cement are the most popular materials used in chemical stabilization of clayey soils. If sulphate exists in the stabilized clayey soil with lime, or if soil is exposed to sulphates, problems such as strength reduction and swelling increase will occur. Reuse of industrial residual such as Rice Husk Ash (RHA) can be beneficial from the economy point of view. RHA includes a proper amount of silica with high specific surface area which is very suitable for activating the reaction between the soil and lime. In this paper, chemical stabilization of gypsum clays using lime and RHA is addressed Sulphates exist in the constitution of the soil. Unconfined compression strength and swelling potentials of the stabilized soil are evaluated. The results of this study indicate that RHA has positive impacts on improving mechanical properties of the gypsum clays stabilized with lime. From the view point of strength and swelling characteristics, and economy, addition of 6–8% lime and 8-10% RHA as an optimum amount is recommended.
Dr Masoud Amelsakhi, Eng Arash Ebrahimi,
Volume 16, Issue 3 (Autumn 2022)
Abstract
This research is a laboratory study to improve the geotechnical properties of fine-grained soils. For this purpose, agricultural waste ash such as sugarcane bagasse, rice husk and almond husk have been used. In this regard, the effect of using ash of the mentioned fibers with at 4, 8 and 12 weight percentages on fine grain clay soils has been investigated. The compaction test results indicate that these additives generally increase the optimum soil moisture and the maximum optimum moisture was observed for the samples made with 12% ash. Also, based on the results of the unconfined compressive strength test, the studied additives have increased the uniaxial strength of the soil. The samples made with 12% ash were the most effective, so that the addition of 12% bagasse ash increased the soil resistance by 117%, and the addition of 12% rice husk ash and almond husk ash increased the soil resistance by 89, 80% respectively.
Hossein Ebrahimi, Farzad Akbari, Soroor Mazrae Asl, Babak Biglari,
Volume 17, Issue 4 (Winter 2023)
Abstract
The Vorskharan karst spring with a catchment area of 50 square kilometers and an average discharge of about 1.35 m2/s is one of the most important springs in the city of Firouzkouh. In order to asses the hydrogeological and hydrogeochemical charachteristics of the spring, the physical and chemical properties of the spring water were measured and analyzed for several months. The results showed that the recession curve of the spring has a slope and the value of its coefficient is about 0.003. The low coefficienof the discharge variation t, electrical conductivity and major ions, as well as the single slope of the spring’s recession curve , are mainly due to the elongated shape of the aquifer and the long-term presence of snow in the catchment basin of the spring. Considering the relatively high water level of the spring and the existence of a sinkhole and a polje in the spring’s catchment area, as well as the coefficient of small changes in the physical and chemical parameters of the spring, it can be said that the dominant flow system in the aquifer which recharges Vorskharan spring,is conduit-diffusive. According to the field studies and the evaluation of the percentage of soil cover, the development of dissolved spaces and other morphological effects of karst, the percentage of annual recharge in the catchment area was estimated at 56%. With the amount of precipitation, the percentage of annual recharge, the annual recharge volume of the preliminary water catchment basin equal to 19.2 MCM and the annual discharge volume of the spring through the annual hydrograph of the spring was calculated to be equal to 20.1 MCM. It was also observed that the type of water is Ca-HCO3, and the lithology of the aquifer is calcareous and dolomite.
