| Summary: | 碩士 === 逢甲大學 === 紡織工程所 === 95 === In the study, nonwoven fabric selvedges and waste containing low melting point fibers were recycled and reused to improve a disadvantage that they could not be reused. The investigation used the selvedges and waste and the low melting point fibers to manufacture geocells, and they could be applied for reinforcement in civil engineering. The geocells were easily stored. The method that the geocells were used in civil engineering could decrease construction time and save materials. In addition, their water permeability could enhance. Each piece of the nonwoven fabric was cohered using a high frequency plastic welding machine to form the geocells, which were three dimension structures. The geocells could take the place of high density geocells in sands. The water permeability of the geocells was higher than that of high density geocells. The effect of cohering conditions (time, electric currents) and areas on the cohering tensile strength of the geocells was discussed. The geocells of different heights were fabricated at the optimal cohering conditions. The indentation phenomenons in sands were observed and evaluated after we drove a car in sands with the geocells. The geocells can be used for the reinforcement in sands.
When the ratio of the low melting point fibers was below 40%, the water permeability of the geocells containing either waste or no waste exceeded (above 1×10-3cm/sec) that of high density polyethylene. The water permeability coefficient of the geocells enhanced with decreasing weights per unit area when their thicknesses were the same. Moreover, when weights per unit area were the same, the water permeability coefficient of the geocells at 30% of the low melting point fibers was increased than that of the geocells at 40%. The cohering tensile strength of the geocells at a tuner scale of 6 exceeded that at a tuner scale of 2 and 4 . Because when the pressure was the same, the high frequency plastic welding power increased with increasing tuner scales. The polyester fibers were melted at short time. Cohering areas increased so the geocells had high cohering tensile strength values.
In the study, the recycled nonwoven fabric selvedges and waste containing low melting point fibers were smashed to form the staple fibers of varied fiber length. In addition, a few nonwoven fabrics could not be completely smashed to form the broken nonwoven fabric pellets. Therefore, when the recycling ratio of the selvedges and waste was 60%, the evenness of the geocells was lower than that of high density polyethylene geocells. The phenomenon resulted in the high frequency plastic welding machine cut off the power supply itself. At this time, the polyester fibers were not melted. This is because electric currents flowed each other between the top and bottom electrode place. Therefore, the cohering tensile strength of the geocells reduced. When a tuner scale was 4 and time was 6.5 seconds, the polyester fibers were completely melted. At this time, the cohering tensile strength of the geocells was more than 100 kgf. When mean weights of the geocells were lower (above 50%) than those of high density polyethylene, the cohering tensile strength of the geocells was approximately the same as that of high density polyethylene.
|
|---|
