泥石流虹吸排水分流池的自清淤能力研究

发布时间：2018-06-07 09:34

本文选题：泥石流 + 虹吸排水　；参考：《浙江大学》2015年硕士论文

【摘要】：我国是泥石流灾害频发的国家,许多泥石流的发生都造成了巨大的灾难。水动力因素是泥石流爆发的重要激发条件。目前的泥石流截、排水技术手段,全部采用重力流形式,不仅土石方工程量大、排水效率低,而且泥石流的高携沙量常常使截排水结构由于淤积而失效。采用具有自清淤能力的水石分离虹吸排水技术防治泥石流的新技术,将可有效提高泥石流治理的效率和耐久性。该方法在泥石流形成区或流通区沟谷内布设分流池进行水石分离,通过虹吸排水管将池内分离出的洪水快速排泄到下游安全区,达到降低泥石流水动力条件。其有益效果在于：可实现泥石流形成和流通过程的有效控制,解决不同规模泥石流沟的治理问题；利用虹吸分流系统实现土石与水的分离,施工简便；虹吸排水将重力流转变为满管流,提高排水效率；虹吸产生的抽吸作用能防止管道淤积,有效提高排水工程使用的耐久性；虹吸式排水管无须坡度控制,安装方便；不涉及大规模的土石方工程和构筑物建设,工程造价低,对环境影响小；在此技术方案中,分流池的清淤问题是虹吸分流系统长期有效的基础,也是推广虹吸排水技术应用于泥石流治理的前提条件。在分流结构中,如果拦污格栅孔隙过小,则容易堵塞失效,导致沟谷洪水无法顺利进入分流池；如果拦污格栅孔隙过大,进入分流池的石块如果无法虹吸带走,则分流池就会被淤积。因此,为合理设计分流系统,需要研究虹吸分流池的水动力学特征。本文通过计算流体数值软件FLUENT建立三维数值模型,对分流池在虹吸作用下的水力特性进行分析,表明分流池在虹吸作用下产生以虹吸管口为中心的向心速度场；分流池池底切应力与作用水头差之间呈一定的线性关系；而在相同水头差作用下,底面切应力与虹吸管径呈指数关系；虹吸管口至池底面的悬空高度在25%的虹吸管径内时,池底面的负压水头达到最大；合理的虹吸进水管后壁距离及多根虹吸管平行布置的结构形式可以有效防止池内泥沙淤积。工程上可以此指导实际泥石流防治中的虹吸分流池设计。
[Abstract]:China is a country with frequent debris flow disasters, many of which have caused huge disasters. Hydrodynamic factor is an important excitation condition for debris flow. At present, debris flow interception and drainage technology all adopt the form of gravity flow. Not only the amount of earth and rock works is large, the drainage efficiency is low, but also the high sediment carrying capacity of debris flow often makes the truncated drainage structure fail because of siltation. The new technology of water stone separation siphon drainage with self-desilting ability to prevent debris flow will effectively improve the efficiency and durability of debris flow control. In this method, a distributary pool is arranged in the gully of debris flow forming area or circulation area to separate water and stone, and the separated flood is discharged quickly to the downstream safety zone by siphon drainage pipe, which can reduce the hydrodynamic condition of debris flow. The beneficial effects are as follows: the formation and circulation of debris flow can be controlled effectively to solve the problem of controlling debris flow gullies of different scales, the separation of soil and rock from water can be realized by siphon distribution system, and the construction is simple and convenient. Siphon drainage can change gravity flow into full pipe flow, improve drainage efficiency, siphon effect can prevent pipeline siltation, effectively improve the durability of drainage works, siphon drainage pipe does not need slope control, and is easy to install. It does not involve large-scale earthwork and structural construction, it is low in cost and has little impact on the environment. In this technical scheme, the problem of silting in the diffuser pool is the basis for the long-term effectiveness of siphon shunt system. It is also the precondition of popularizing siphon drainage technology in debris flow control. In the distributary structure, if the pore of the griddle is too small, it is easy to clog and fail, resulting in the flood of the gully can not enter the pool smoothly; if the pore of the griddle is too large, the stones entering the shed can not be siphoned and taken away. Then the shunt pool will be silted up. Therefore, in order to design the distributary system reasonably, it is necessary to study the hydrodynamic characteristics of siphon diffuser. In this paper, a three-dimensional numerical model is established by the numerical software FLUENT, and the hydraulic characteristics of the distributary pool under the siphon action are analyzed. The results show that the concentric velocity field with the siphon orifice as the center is produced under the siphon action. There is a linear relationship between the shearing stress at the bottom of the diffuser pool and the acting head difference, but under the same head difference, the bottom shear stress is exponentially related to the siphon diameter, and the suspended height from the siphon orifice to the bottom surface of the siphon pipe is within 25% of the siphon diameter. The negative pressure head on the bottom of the pool reaches the maximum and reasonable siphon inlet pipe back wall distance and parallel arrangement of multiple siphon pipes can effectively prevent silt deposition in the pool. Engineering can guide the siphon diversion pool design in the actual debris flow prevention.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.23

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