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目的:探索长时间停流情况下高扬程虹吸管中空气累积现象的发生发展及其对虹吸持续工作的危害,并给出应对该现象的工程预防措施。创新点:利用物理模型实验,结合理论解析推导,得到高扬程虹吸管内空气累积的原因及关键影响因素,突破高扬程虹吸排水在少雨地区的使用局限,给出其长期适用的工程设计条件,对其在实际边坡工程中的推广应用提供理论技术指导。方法:通过物理模型试验,揭示长期停流虹吸管内出现空气累积的必然性;利用理论公式推导,对不同因素的影响结果进行对比分析,得出影响空气累积的主要因素。结论:1.溶于水的空气因压力降低而析出、管端空气溶入扩散到虹吸管顶部及温度变化引起空气析出等现象是无法避免的;其中,原有空气的析出及温度变化引起的空气累积是主要因素;2.边坡虹吸排水设计时进水端口距控制水位至少应预留2.05 m的地下水位上升余量,或者保持出水口的高程比进水口高程低4.1 m来保证析出空气段处于下水管中。
OBJECTIVE: To explore the occurrence and development of air accumulation in high-lift siphon tube under long-term shutdown and its harm to continuous siphon work, and to provide engineering precautionary measures to deal with this phenomenon. Innovative point: the use of physical model experiments, combined with theoretical analysis derived high-lift siphon air accumulation causes and key factors that break through the high-lift siphon drainage in the useless rain limited areas, given its long-term engineering design conditions applicable to It provides theoretical and technical guidance in the popularization and application of practical slope engineering. Methods: Through the physical model test, we revealed the inevitability of air accumulation in the long-term shutdown siphon. By using the theoretical formula, we compared and analyzed the influence of different factors and obtained the main factors that affect the air accumulation. Conclusion: 1.Water-soluble air is precipitated due to the decrease of pressure, and the air diffused into the top of the siphon pipe at the end of the pipe and the precipitation of air due to the temperature change are unavoidable. Among them, the air caused by the precipitation and the temperature change 2. Slope drainage siphon design water inlet port from the control level should be reserved for at least 2.05 m of groundwater level rise margin, or to maintain the outlet elevation lower than the inlet 4.1 m to ensure the precipitation of air section In the sewer.