In this paper,the use of recycled tire-derived aggregates(TDA)mixed with ballast material is evaluated in order to reduce the train-induced ground-borne vibrations.For this purpose,a series of field vibration measurem...In this paper,the use of recycled tire-derived aggregates(TDA)mixed with ballast material is evaluated in order to reduce the train-induced ground-borne vibrations.For this purpose,a series of field vibration measurements has been carried out at an executed pilot track.The prepared ballast layer was mixed with different percentages of TDA in three sections.Moreover,another test section with pure ballast is considered as a reference.The vibrations generated by a motor-powered draisine at two different speeds are then recorded.Records of vibration data are provided using four seismometers placed once longitudinally and once transversely beside different sections.The outputs are then processed in both velocity–time and velocity–frequency domains.To verify the vibration mitigation performance of TDA in real operation conditions,field measurements under the passage of two planned passenger and freight trains are finally arranged.Results show that the best TDA mixture ratio,i.e.,10%by weight,can reduce the transmitted vibrations up to 12 dB for frequencies above 31.5 Hz.According to the obtained effi-ciency and the very low cost of the recycled materials,this solution can be considered as a competitive vibration countermeasure.展开更多
The seismic behavior of Tire Derived Aggregate （TDA） used as backfill material of 6.10 m high retaining walls was investigated based on nonlinear time-history Finite Element Analysis （FEA）. The retaining walls wer...The seismic behavior of Tire Derived Aggregate （TDA） used as backfill material of 6.10 m high retaining walls was investigated based on nonlinear time-history Finite Element Analysis （FEA）. The retaining walls were semi- gravity reinforced concrete cantilever type. In the backfill, a 2.74 m thick conventional soil layer was placed over a 3.06 m thick TDA layer. For comparison purpose, a conventional all soil-backfill model was also developed, and the analysis results from the two models under the Northridge and Takatori earthquakes were compared. The FEA results showed that both models did not experience major damage in the backfill under the Northridge earthquake. However, under the Takatori earthquake, the TDA-backfiU model developed substantially large displacement in the retaining walls and in the backfill compared with the soil-backfill model. Regions of large plastic strain were mainly formed in the TDA layer, and the soil over the TDA layer did not experience such large plastic strain, suggesting less damage than the soil-backfill model. In addition, the acceleration on the backfill surface of the TDA-backfill model decreased substantially compared with the soil-backfill model. If an acceleration sensitive structure is placed on the surface of the backfill, the TDA backfill may induce less damage to it.展开更多
文摘In this paper,the use of recycled tire-derived aggregates(TDA)mixed with ballast material is evaluated in order to reduce the train-induced ground-borne vibrations.For this purpose,a series of field vibration measurements has been carried out at an executed pilot track.The prepared ballast layer was mixed with different percentages of TDA in three sections.Moreover,another test section with pure ballast is considered as a reference.The vibrations generated by a motor-powered draisine at two different speeds are then recorded.Records of vibration data are provided using four seismometers placed once longitudinally and once transversely beside different sections.The outputs are then processed in both velocity–time and velocity–frequency domains.To verify the vibration mitigation performance of TDA in real operation conditions,field measurements under the passage of two planned passenger and freight trains are finally arranged.Results show that the best TDA mixture ratio,i.e.,10%by weight,can reduce the transmitted vibrations up to 12 dB for frequencies above 31.5 Hz.According to the obtained effi-ciency and the very low cost of the recycled materials,this solution can be considered as a competitive vibration countermeasure.
文摘The seismic behavior of Tire Derived Aggregate （TDA） used as backfill material of 6.10 m high retaining walls was investigated based on nonlinear time-history Finite Element Analysis （FEA）. The retaining walls were semi- gravity reinforced concrete cantilever type. In the backfill, a 2.74 m thick conventional soil layer was placed over a 3.06 m thick TDA layer. For comparison purpose, a conventional all soil-backfill model was also developed, and the analysis results from the two models under the Northridge and Takatori earthquakes were compared. The FEA results showed that both models did not experience major damage in the backfill under the Northridge earthquake. However, under the Takatori earthquake, the TDA-backfiU model developed substantially large displacement in the retaining walls and in the backfill compared with the soil-backfill model. Regions of large plastic strain were mainly formed in the TDA layer, and the soil over the TDA layer did not experience such large plastic strain, suggesting less damage than the soil-backfill model. In addition, the acceleration on the backfill surface of the TDA-backfill model decreased substantially compared with the soil-backfill model. If an acceleration sensitive structure is placed on the surface of the backfill, the TDA backfill may induce less damage to it.
