实时监控下堆石坝压实质量模糊综合评估

堆石坝填筑碾压质量采用事中和事后双控。事中碾压参数往往不能在全工作仓面上100%满足控制要求,且受坝料性质不均匀的影响,即便是相同的碾压参数,也可能会导致不同的压实质量。事后试坑检测采用有限个测点,难以客观反映整个施工仓面的压实质量;若单纯采用压实连续检测指标(如CV)控制,其与坝料压实质量之间也存在一定误差。文章利用大坝填筑碾压质量实时监控技术,在动态采集碾压参数和压实连续检测指标CV的基础上,采用Dempster-Shafer(D-S)证据理论,提出了一种综合考虑事中碾压参数、事后CV的压实质量模糊综合评价方法。此外,为了保证碾压区域无明显连续薄弱区,通过DBSCAN空间聚类分析,提出等效连续薄弱面积的概念,对压实质量薄弱区域空间分布进行定量评价。实例分析表明,此方法可以有效避免单独事中或事后评估的片面性,提高压实质量评估的全面性,为高堆石坝施工质量控制提供一种新的手段。

Fuzzy comprehensive evaluation of earth-rock dam compaction quality based on real-time monitoring

The traditional quality assessment method of earth-rock dam compaction is primarily based on control parameters collected from the job site of compaction and by sampled spots testing. Compaction parameters cannot satisfy the requirement by every location of the entire working surface, and using the same parameter may lead to different compaction quality due to the influence of inhomogeneity in material property. A limited number of test samples are usually an unreliable representation of compaction quality over the entire surface layer, and a certain error occurs when compaction value (CV) alone is used in the evaluation. This paper describes a fuzzy comprehensive compaction quality evaluation method based on the Dempster-Shafer evidence theory and dynamical monitoring of compaction parameters and CV. We also develop a concept of equivalent continuous weak area using the density-based spatial clustering of applications with noise (DBSCAN) to ensure that no obvious continuous weak area occurs in the compacted layer, and apply it to quantitative evaluation of the spatial distribution of weak areas. Case analysis shows that our evaluation method can effectively avoid one-sidedness in evaluating compaction parameters and enhance the comprehensiveness of compaction quality assessment, thereby providing a new way for quality control in earth-rock dam construction.