Physical And Mechanical Characteristic Study Of Waste Plastic Bottle Debris Reinforced Soil

In civil engineering, the lateral earth pressure of retaining wall, the bearingcapacity of foundation, stability of soil slope and the foundation and so on are directlyrelated to the shear strength of soil. During calculation of these problems, shear strengthparameters, i.e., the cohesion and internal friction Angle of the soil must be properlychosed. At present, some researchers have studied the shear strength of fiber andrubber particles reinforced soil. These investigations showed that a moderate amountof fiber content can significantly improve the shear strength of soil. However, the highprice of synthetic fiber increased the cost of the reinforced soil, which limited itsapplication. Fragments of waste plastic bottle is cheaper and the reinforcing principle issimilar to synthetic fiber. There will be a better promotion value if fragments of wasteplastic bottle can be used. Therefore, it is necessary to investigate the shear strength andstress-strain relationship characteristics of soil reinforced by waste plastic bottle pieces.In this study, direct shear tests were conducted on soil reinforced by waste plasticbottle pieces to investigate the shear strength and stress-strain relationshipcharacteristics of it. The ShearTrac-Ⅲ direct shear instrument was used in the tests.Influence of water content, shape and volume percentage of waste plastic bottle pieceswas investigated during the tests. The diameter of the plastic bottle filiform material isless than or equal to1mm. The length of the material was1cm,2cm, and3cm,respectively. The grain size of particle fragments was equal to or greater than1cm.Volume percentage for all kinds of filiform plastic bottle fragments was2.5%,5%and 10%, respectively. Volume percentage of plastic bottle Granular fragments percentagewas20%. In this thesis, shear stress and shear displacement relationship curvesunder different conditions were obtained by a certain amount of shear tests. Theoptimal volume percentage of plastic bottle pieces for an individual shape of wasteplastic bottle pieces can then be determined. In addition, by comparing the results underthe same volume percentage, the best shape of plastic bottle pieces can be obtained. Byanalyzing the shear stress and shear displacement relationship curves of reinforced soilas well as the shear strength parameters (internal friction Angle and cohesive force),the following results are obtained:i. Optimal water content and of maximum dry density of loess soil and2:8limeearth were obtained using compaction tests. The Optimal water content and ofmaximum dry density were17.4%and1.75for loess, and22.3%and1.68forlime earth, respectively.ii. Based on the shear test of reinforced soil under different conditions, it can beconcluded that the best length for filiform waste plastic bottle pieces is3cm. Thecorresponding optimal volume percentage is5%.iii. When the volume percentage of plastic bottle pieces is less than or equal to5%,the permeability coefficient of reinforced soil increased with the increase involume percentage. However, when the volume percentage is greater than5%,the permeability coefficient decreases with the increase in volume percentage.