摘 要*

平原灌区水闸闸下冲刷破坏严重且普遍存在。冲刷破坏位置绝大多数发生在消力池下游海漫及防冲槽处。冲刷破坏原因很多，当消力池设计合理，闸下出流消能充分的情况下，海漫末端仍会产生冲坑，其产生的原因除还有剩余的应消未消的动能外，主要是由于断面流速未恢复常态，近底流速偏大所致。经研究观测发现，海漫未充分发挥进一步消除余能，调整断面流速分布以降低海漫近底流速是其一大原因。本文在对海漫加糙已有研究的基础上，针对八排糙体等间距梅花状均匀布置展开研究，在已有的条件下进行恒定流动床模型试验。试验根据已有的研究成果及试验过程中出现的现象，设计了四种方案，进行了两个流量的模型试验。
在对各方案进行大流量试验时，发现各方案均较未加糙减小冲刷60%－70%，比较各方案选出方案4为优选方案，海漫缩短约37.5%的工程量。随下游水位的降低，所需消力池深增加，未加糙情况出现远驱式水跃，而加糙后出现淹没式水跃，水位雍高值稍大于所需增加的消力池深值；且加糙后对池长影响不大。所以池深、池长建议按照原未加糙设计方法设计，均偏于安全。海漫长度设计建议无尾坎消力池按Lp＝9.5D（D为轮胎直径）计算，有尾坎消力池再增加0.5m坎的宽度。
为模拟非恒定流试验，对方案1和4进行了小流量试验，结果发现出现了预料的下游低水位缩水攻沙的冲刷现象。有利的是随下游水的降低，冲刷并没有再加剧。由于试验条件及时间所限，试验均以恒定流近似模拟非恒定流，所得结论还有待实际工程试验验证。

关键词：海漫；糙体；布置形式；防冲；近底流速；断面流速

Abstract:
Under the plain irrigation area dam floodgate washes out the
destruction to be serious also the universal existence. Washes out
destroys the position overwhelming majority to occur in the toe basin
downriver sea inundates and guards against flushes the trough place.
Washes out the destruction reason very many, when the toe basin design
is reasonable, under the floodgate the class disappears can in the
full situation, the sea inundated the terminal still to be able to
produce flushes the pit, it produced the reason besides also had the
kinetic energy which surplus should disappear, mainly was because the
cross section speed of flow has not restored the habit, the near
bottom speed of flow was the result of greatly. After the research
observation discovery, the sea inundates not the full display further
to eliminate -odd energy, the adjustment cross section speed of flow
distribution by reduces the sea to inundate the near bottom speed of
flow is its big reason. This article in inundates to the sea adds
coarse had the research in the foundation, in view of spacing plum
efflorescent even arrangement and so on eight row of coarse the bodies
launches the research, in had under the condition carries on the
constant fluidized bed model experiment. The experimental basis had in
the research results and the testing appear the phenomenon, has
designed four kind of plans, has carried on two current capacities
model experiments.
When carries on the great current capacity experiment to various
plans, discovered various plans have not added coarse reduce wash out
60% - 70%, selects plan 4 compared with various plans is the optimal
plan, the sea inundates reduces approximately 37.5% resiliences. Along
with downriver water level reducing, needs the toe basin deep
increase, has not added the coarse situation to appear far drives the
type momentum discontinuity, after but adds coarse appears the
submergence type momentum discontinuity, water level Yong Gaozhi is
bigger than the toe basin deep value slightly which must increase;
After also adds coarse is not big to the pond long influence.
Therefore the pond depth, the pond long suggestion according to
original has not added the coarse design methods design, in favors of
the security. The sea inundates the length design proposal tailless
ridge toe basin (D is tire diameter) calculates according to Lp =
9.5D, has the ridge toe basin to increase the 0.5m ridge again the
width.
In order to simulate the non- steady flow experiment, 1 and 4 has
carried on the small current capacity experiment to the plan, finally
discovered appeared the expectation downriver low water level
synaeresis to attack the sand to wash out the phenomenon. Advantageous
is along with tailwater reducing, washes out not again intensifies.
Because the test condition and the time limit, the experiment
approximately simulates the non- steady flow by the steady flow, the
obtained conclusion also waits for the actual engineering test
confirmation.

Key word: The sea inundates; Coarse body; Arrangement form; Guards
against flushes; Near bottom speed of flow; Cross section speed of
flow