بهينه سازي اصلاح خاك متورم شونده با استفاده از سرباره و الياف

چكيده انگليسي :

Optimization of the Modification of Expansive Soil by Steel Slag and Fibers Maryam Shahbazi maryam shahbazi@cv iut ac ir January 07 2015 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language Persian Supervisors M A Rowshanzamir Assist Prof Email address mohamali@cc iut ac i M Vafaeian Prof Email address mahmood@cc iut acAbstractExpansive clayey soils usually exhibit great volume change with any moisture variation The soils are also weakand have limited strength These features cause limitations and high risks for constructing dams highways andother engineering structures on such soils A common technique to overcome the weaknesses of the clayey soilsis to stabilize them using appropriate additives In the present study with an environmental approach steelindustry by products slag and waste fibers from carpet manufacturing acrylic fibers were added to two typesof expansive soils to evaluate likely improvement effects The selected expansive clays include of bentonite clay B and a composition of bentonite clay with 10 of local ordinary clay C 10B classified respectively as veryhigh and high expansive soils In this regard using statistical software design expert was employed to designthe necessary experimental tests to investigate the effects of important variables on the soils improvements Theeffects of independent variables such as the amounts of additives i e slag and fiber separately and theircombined values on the soils swelling indexes as well as compaction and strength properties were investigated The various amounts of slag 0 to 25 and fiber 0 2 to 3 with different aspect ratios 5 to 45 wereconsidered in the conducted tests The results showed that adding 25 to soil B caused about 50 reduction atthe swell pressure and free swell of soil Similarly for the C 10B soil the swell pressure and free swell werereduced about 92 percent by adding 25 slag For soil B samples with 3 fibers of 25 aspect ratio the swellpressure and free swell decreased 25 and 70 percent respectively in comparison to that of pure soil Furthermore for the soil C 10B samples with the same amount of fiber swell pressure and free swell decreased 88 and 92percent respectively Adopting 1 6 fiber as an optimum additive the effect of fibers aspect ratio was consideredwith changing L D from 5 to 45 This increase in the fiber aspect ratio caused 40 reduction at swell pressureand free swell for both soils In the both soils increasing the slag and fibers showed decreasing effect on theswell and swell pressure of the soils while the effect of slag was more eminent in comparison to that of fiber andL D Plotting appropriate 3D graphs through Expert Design software optimal conditions for soil B improvementi e sufficient reduction of swelling to a medium level the amount of slag and fibers and L D were evaluated at25 2 5 and 40 respectively Similarly optimal conditions for soil c 10B in order to reduce swelling andincrease the strength with the appropriate amount of modifier additives the amount of slag fibers and L D wereestimated at 15 0 4 and 45 respectively With these amounts of additives the free swell and swell pressure ofc 10B soil changed from 8 65 and 80 65kPa to 1 and 17kPa respectively so that the level of expansionreached to low expansion category Key words Clay soils expansive soil free swell swell pressure modifier slag fiber optimization

شهبازي، مريم

بهينه سازي اصلاح خاك متورم شونده با استفاده از سرباره و الياف

خاك رس , تورم آزاد , فشار تورم , اصلاح كننده