基于典型小概率法的土石坝倾度安全监控指标拟定

Typical Low Probability Method Based Determination of Inclination Security Monitoring Index of Earth-Rock Dam

针对实际土石坝工程中判断大坝是否发生沉降不协调常使用临界倾度经验值未关联大坝实测沉降的问题,提出了基于典型小概率法拟定倾度监控指标,该方法先由相邻测点的长序列实测沉降计算出倾度值,然后选取不利荷载组合下的倾度组成小子样,接着采用K-S检验法确定样本的概率密度函数,最后采用小概率事件法拟定倾度的监控指标。结果表明,陆水~#8土石坝3组不同部位处的倾度样本均服从正态分布,小概率事件法拟定的倾度监控指标大小差异较大,且均远小于临界倾度经验值,可看出对于运行期土石坝不同部位沉降协调监控,联系实测沉降拟定的倾度监控指标更加具有针对性,其值更加准确。

In view of the critical inclination experience value, which is often used to judge whether the settlement of the dam is incongruity in actual earth-rock dam project, is not related to the measured settlement of the dam, inclination security monitoring index of the earth and rock dam was proposed based on the typical low probability method. Firstly, the method calculated the inclination value from the long series of measured settlements of adjacent measuring points. Then the inclination values under unfavorable load combination were selected to form small samples, and the probability density function of samples was determined by K-S method. Finally, the monitoring index of the inclination was developed by using the method of small probability event. The results show that from Lushui8 earth-rock dam of the three groups of inclination sample both obey normal distribution, the difference of inclination monitoring index by small probability events is bigger, and the critical inclination is much smaller than the empirical value. It can be seen that for the coordinated monitoring of settlement of different parts of earth-rock dam during operation period, it is more targeted to formulate the monitoring index of inclination based on the measured settlement, and the value is more accurate.