大尺度土坝漫顶溃决试验工程性态测试与分析

Monitoring and analysis of full-scale embankment overtopping failure tests

漫顶是土坝溃决的主要原因。利用原体试验土坝(坝高9.7 m),应用渗流压力、水分、测斜、分布式光缆等传感器及数据采集系统,开展了漫顶溃决试验工程性态测试研究,获取了试验坝填筑、分阶段蓄水和溃决过程的渗流、温度和变形的测试数据及变化特征。测试结果分析表明:坝体渗流压力与库水位明显相关,坝体含水率灵敏性比渗流压力灵敏性快;坝体水平位移由向上游逐渐向下游发展,坝体最大倾度2.242°,坝顶表面最大沉降率为5.21%。测试结果为土坝灾变机理研究及溃坝早期预警提供基础数据。

Overtopping is one of the major factors leading to embankment dam failure. In order to study dam performance and evolution before dam failure, a full-scale overtopping failure test on embankment dam with the maximum height of 9.7 m is carried out. The monitoring techniques for the test with various instruments are introduced, including water level gauges, thermometers, osmometers, piezometer tubes, distributed optical cables, moisture transducers, inclinometers, multi-parameter transducers, total station, level gauges, etc. The seepage, deformation, temperature data and variation characteristics of the dam are monitored from dam filling, initial impounding to dam failure. The monitoring data are analyzed, showing the reliability and validity of the osmometers, moisture transducers, inclinometers and multi-parameter transducers, and their monitoring techniques are verified. The moisture transducers are more sensitive than the osmometers during reservoir impounding. The dam body deflects from upstream to downstream with the increase of reservoir water. The observed maximum dam settlement is 5.21%, and the observed maximum dam inclination is 2.242°. The research results are valuable to the study on the evolution mechanism of dams and the early-warning indices of unexpected accidents.