In order to effectively control low-frequency vibrations in engineering practice,the structure and the formation mechanism of the band gap were analyzed,and the finite element method was employed to investigate the influencing factor of the band gap in combined periodic cross-isolation trenches. Subsequently,this study analyzed vibration isolation performance using the model experiment. The results show that the band gap characteristics of the combined periodic cross-isolation trenches are mainly influenced by the periodic constant,the depth of the channel,the elastic modulus of soil and the filling medium. With the increase of the period constant,combined periodic cross-isolation trenches are more likely to obtain the low-frequency band gaps,but the bandwidth narrows. By increasing the depth,the low-frequency band gap with a larger bandwidth can be obtained,and the number of band gaps increases. With the increase of elastic modulus,the boundary frequency of the band gap migrates to high frequency synchronously,and a more low-frequency and wider band gap can be obtained by filling the medium. The experimental results show that the maximum attenuation amplitude of acceleration in the band gap range reaches 0.001 24 m/s2,the average amplitude attenuation ratio in the band gap is 0.206 2,and the maximum attenuation degree reaches 98.4%. The combined periodic cross-isolation trenches have remarkable vibration isolation performance.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |