Soft Soil Stabilization by Electrokinetic Method Using Sodium Silicate and an Additive (CO2)

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Soft Soil Stabilization by Electrokinetic Method Using Sodium Silicate and an Additive (CO2)

ارائه دهنده: Provider: Meisam Ghorbani

اساتید راهنما: Supervisors: Masoud Makarchian (Ph.D)

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: دکتر وحیدرضا اوحدی - دکتر عباس قدیمی

زمان و تاریخ ارائه: Time and date of presentation: August, 07, 2020

مکان ارائه: Place of presentation: آمفی‌تئاتر

چکیده: Abstract: According to the growing population of the world and the limitations of suitable land for construction, improvement and modification of land is inevitable. One method to improve is to use an electrochemical process called electro-kinetics. In this method, the electric current passes through the conductive particles through the soil grains and minerals by conductive electrodes. These particles, by chemical reactions with soil grains or the formation of sticky bonds, bind the soil particles together, thus enhancing the shear strength and bearing capacity of the soil. In this method, various materials are used as a solution; one of the most common and best choices is sodium silicate. In this study, by using waterproof wooden molds, the specimens were prepared and compacted at a height of 9 cm by the wet tamping method in the form of one-centimeter layers in a moisture content of 27% and concentrations of 5% and 10% sodium silicate were used at a voltage of 1.75 V/cm using a pump. Factors studied in this study include the curing time of sample, the concentration of electro-osmotic solution and the duration of the electro-osmotic flow. The resistance test is also performed by the CPT to calculate Shear strength capacity of the soil. The experimental results of this study, based on the results of the cone penetration tests, showed that the use of sodium silicate in the electro-seismic method to stabilize kaolinite soils increases the unconfined shear strength (UCS) of the samples stabilized by this method at the concentration of 10%. In some cases, the improvement ratio is as high as 168%. Moreover, effect of using CO2 gas along with sodium silicatet show that increases the unconfined shear strength (UCS) of kaolinite soil. However, its together use with sodium silicate does not have a greater effect on increasing the shear strength of the soil. Experiments have shown that the simultaneous use of sodium silicate and CO2 improves homogeneous shear strength distribution in all parts of the sample compared to conditions where sodium silicate used for stabilization alone. Also, improves up to 90% of the final shear strength of specimens from the beginning of the process. Also, the results of the secant deformation modulus (E50) of the specimens shows that soil stabilization increases the ductility range, and also increases the UCS strength of the soil and reduces its brittleness. Key Words: Stabilization, Clay, Electrokinetic, Sodium Silicate, CO2, UCS, CPT