بررسي پارامترهاي مقاومتي خاك ماسه اي و ماسه اي لاي دار مسلح به الياف پلي پروپيلن و تراشه هاي لاستيك فرسوده

چكيده انگليسي :

An Investigation On Strength Parameters Of Sand And Silty Sand Soils Reinforced With Polypropylene Fiber And Tire Chips Sayyed Hamid Mousavi Zahed h mosavi98@yahoo com Date of Submission March 13 2011 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Dr Mohammad Ali Rowshan Zamir mohamali@cc iut ac ir Abstract The construction of engineering structures on soft and loose soils may involve lot of risks due to differentialsettlements shear failures and other instabilities One of the principal methods for stabilizing such soils isreinforcing them with tensile elements Nowadays considering the production of massive amount of waste fromindustrial factories as well as old and unused materials such as worn tires their disposal is a major issue inenvironmental engineering Thus many attempts have been made to use these materials for improving soilengineering properties and so reduce the environmental pollutions Polypropylene fibers PP fiber and worn tiresare two types of the waste materials which attracted increasing attentions in soil reinforcement usages Neverthelessthe mixed effects of these materials on the soil properties have not been discussed till now The main aim of thisresearch study is to investigate the strength parameters of sandy and silty sand soils reinforced with tire chips and PPfibers both in individually and combined percentages using direct shear and CBR tests In this study tire chips with 24 mm length 6 mm width 5 mm thickness and aspect ratio of 4 mixed with thesoil samples in contents of 15 18 21 and 25 by weight of dry soil The PP fibers were creamy colour fiberswith random lengths produced as waste materials of carpet factories Thus the effects of their lengths could not beconsidered in this investigation These fibers were also added and mixed with soil samples in weight percentages of0 1 0 2 0 3 0 4 0 6 and 0 8 for conducting different strength tests Direct shear tests on the sandy samples as well as silty sand samples reinforced with PP fibers showed that thereinforcement makes an increase in the shear strength internal friction angle and cohesion of the soil samples However the amount of increase in the soil cohesion was more pronounced in comparison with internal frictionangle Based on the obtained results the optimum percentage of fibers for achieving maximum strength was 0 4 for the sand and 0 3 for the silty sand The direct shear tests on sandy samples reinforced with rubber chipsshowed results similar to those of fibers i e the soil cohesion was most affected by the amount of chips Nevertheless adding the chips to silty sandy soil was most effective on the soil internal friction angle The optimumpercentage of chips for achieving maximum strength was 21 for the sand and 25 for the silty sand Combiningthe sandy soil samples with the fiber content of 0 4 and various amounts of tire chips it was found that the chipscontent of 21 had the most increasing effect on the strength of the sandy samples with combined reinforcement offibers and chips Also mixing the sandy soil samples with the chips content of 21 and various amounts of fibers itwas observed that the fibers content of 0 3 had the most enhancing effect on the strength of the sandy sampleswith combined reinforcement of chips and fibers Moreover in the silty sandy soil samples mixed with acombination of optimum percentage chips 25 and different contents of fibers it was found that the fibers of0 1 was the most effective content on the strength enhancement of the silty sand samples with combinedreinforcement of chips and fibers The optimum content of tire chips in silty sand samples mixed with o 3 of fiberswas also found to be about 21 CBR tests on PP fibers mixed with sand and rubber chips indicated the positive influence of the reinforcementson the soil CBR The optimum contents of the sandy soil reinforcements were found to be 0 3 for fibers and 21 for rubber chips Neverthele

موسوي زاهد، حميد

بررسي پارامترهاي مقاومتي خاك ماسه اي و ماسه اي لاي دار مسلح به الياف پلي پروپيلن و تراشه هاي لاستيك فرسوده

برش مستقيم , CBR