For the long-distance water supply project where the pump station pressurizes before the high point and gravity flows after the high point, when the end valve is closed in a straight line in case of power failure in an accident, a longer valve closing time is required to meet the pressure control standard, which virtually increases the scale of the protective measures and increases the investment. In order to solve this problem, a broken line valve closing rule is proposed to reduce the volume of protective measures while optimizing the pressure. The characteristic line method is used to check each scheme through FORTRAN programming, and the general rule is summarized by analyzing the influencing factors of the main parameters. The case results show that the broken line valve closing can reduce the volume of protective measures and reduce the project cost compared with the straight line valve closing within the same valve closing time under the premise of ensuring that the pressure meets the requirements.
| 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 |