| 题名 | 泥石流重力式拦挡坝坝后回淤坡度与坝高及沟床纵比降关系的实验研究 |
| 作者 | 李峰 |
| 学位类别 | 硕士 |
| 答辩日期 | 2011-05-14 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 马东涛 |
| 关键词 | 泥石流 重力式拦挡坝 沟床 回淤坡度 比降比值（K） |
| 其他题名 | Experiment on Relationship between Slope of Intercepted Sediments behind Gravity Check-dam with the Gradient of Gully Bed and the Height of Dam |
| 学位专业 | 岩土工程 |
| 中文摘要 | 拦挡坝是泥石流防治中常用的工程措施之一，其具有良好的拦砂效能，可以有效减缓局部沟道纵坡、稳固上游岸坡坡脚、减少崩塌滑坡物质供给等功能。回淤坡度是拦挡坝设计一项很重要的参数，其直接影响拦截库容和工程效益。研究泥石流拦挡坝坝后回淤坡度对泥石流拦挡工程设计十分重要。模拟实验是泥石流研究的一种方法。本文以中国科学院山地灾害与地表过程重点实验室动力学实验大厅为试验平台，对泥石流在拦挡坝后的淤积情况进行了实验，分析了9cm、12cm、15cm、18cm、21cm等5组坝高及12%、14%、16%、18%、20%等5组沟床纵纵比降组合条件下，重力式拦挡坝坝后回淤坡度的变化规律。通过实验研究得到以下结论：（1）坝高及沟床纵比降变化都会引起坝后淤积坡度的变化，它们是影响坝后回淤坡度的主要因素。（2）坝高一定，坝上游回淤坡度与沟床纵比降呈线性正相关关系。相同条件下粘性泥石流回淤坡度比稀性泥石流大。（3）沟床纵比降一定，坝后回淤坡度与坝高呈二次曲线关系，即回淤坡度随坝高的增大先增加后减小。但曲线的变化速率不同，在纵比降为小于16%时，曲线变化速率较小，纵比降大于16%，曲线变化速率较大。（4）引入比降比值的特征参数K，来表征坝后回淤坡度的变化。K与坝高及沟床纵坡均为二次曲线关系。随坝高增大，K先增大后减小；坝高在9～15cm时，K随着沟床纵比降增大，呈先增大后减小的趋势；当坝高在15～21cm范围内，K随沟床纵比降的增大，呈先减小后增大的规律。（5）稀性泥石流坝后淤砂形态相似，在淤砂区的前部，淤砂高度都大致等于坝体高度，在淤砂区的尾部，都有一个明显的陡坎。沟床纵比降越大，坝下冲刷坑的冲刷深度越大；沟床纵比降一定时，坝高越高，坝后淤砂长度越长。 |
| 英文摘要 | As an important obstructed measure in debris flow control engineering, the gravity check-dam has good sediment-intercepting effects, which can slow down the trench lengthwise grade, making upstream bank slope toe steady, reducing avalanche landslide and debris flow effectively. Slope of intercepted sediments is an important parameter for gravity check-dam design, which affects the designed capacity to retain deposit of debris flow, and it decides whether the sediment storage dam structure is effective and reasonable. The research on the slope of intercepted sediments is significient for gravity check-dam engineering. Laboratory experiment is an important measure for the debris flow research and mitigation. With the support of Key Laboratory of Mountain Hazards and Surface Processes, the Chinese Academy of Sciences, based on the back silting analyses of the gravity check-dam, and analyzing the experimental data about the variation discipline between gradient (12%, 14%, 16%, 18% and 20%), the height of the dam ( 9cm, 12cm,15cm, 18cm and 21cm) and slope of intercepted sediments behind the dam, the below conclusions are gotten: （1）Both gradient and the height of dam change can lead to the back silting of the gravity check-dam. They are the major influencing factors affecting the slope of intercepted sediments. （2）Under the certain height of dam, the relationship between gradient and the slope of intercepted sediments behind the dam are linear positive correlation. Under the same condition, the slope of intercepted sediments of viscous debris flow is bigger than diluted debris flow. （3）Under the gradient certain condition, the relationship between the height of dam and the slope of intercepted sediments behind the dam are in quadratic curve correlation, and the slope of intercepted sediments behind the dam increase first, and decrease with the increase of the height of dam later. The speed variation of the quadratic curve is varietal, when the gradients are smaller than 16%, the amplitude are small, while gradients are greater than 16%. （4）The gradient ratio parameter K is put forward for describing variation of ravine bed after dams constructed, which is in quadratic curve correlation with both height of dam and gradient.In general, gradient ratio increase first, and decrease with the increase of the height of dam later. When the height of dam within 9cm～15 cm, gradient ratio increase first, and decrease then with the increase of the gradient later.As the height of dam within 15～21 cm, gradient ratio decrease first, but increase then with the increase of the gradient. （5）During experiment on scour pit of diluted debris flow, the morphology of slit behind of the dam are similar.In the front of intercepted sediments, the height of intercepted sediments is almost equal to the height of gravity dam near the foreside of dam body. At the tail of intercepted sediments, there is a steep slope. The more gradient bigger, the more the depth of scour pit; under the gradient certain conditions, the more dam higher, the more the length of intercepted sediments longger, besides, the height of dam is independent of the depth of scour pit. |
| 语种 | 中文 |
| 公开日期 | 2013-01-24 |
| 内容类型 | 学位论文 |
| 源URL | [http://192.168.143.20:8080/handle/131551/4835]  |
| 专题 | 成都山地灾害与环境研究所_山地灾害与地表过程重点实验室 |
| 推荐引用方式 GB/T 7714 | 李峰. 泥石流重力式拦挡坝坝后回淤坡度与坝高及沟床纵比降关系的实验研究[D]. 北京. 中国科学院研究生院. 2011. |
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