基于变形倾度的高心墙堆石坝坝顶开裂影响因素分析

An Analysis of the Influencing Factors of Crest Cracking of High-core Rockfill Dam Based on Deformation Gradient Method

高心墙堆石坝因赋存环境复杂,载荷大、应力水平高,坝体安全受到广泛关注。实际工程中坝顶开裂现象时有发生,影响大坝的防渗和稳定,分析和研究影响坝顶开裂的相关因素对大坝设计和运行具有重要意义。基于此,通过对比典型大坝开裂前后坝顶变形倾度的变化规律,将变形倾度作为衡量指标进行了高心墙堆石坝坝顶开裂的影响因素分析。基于多座已建高心墙堆石坝相关信息,构建了考虑坝体尺寸、覆盖层厚度、蓄水高度及速率和运行时间的研究方案。结果表明,坝顶变形倾度随坝体高度增加而显著增大,二者呈非线性增长关系。建于深厚覆盖层上的高心墙堆石坝坝顶开裂风险更大,但覆盖层厚度达到100 m以上时,坝顶变形倾度趋于收敛。坝顶变形倾度对高蓄水位更加敏感,且随着蓄水速率的加快,坝顶变形倾度变大。

The safety of high-core rockfill dams has sparked widespread concern due to their complex environments,large loads and high stress levels.However,crest cracking occurs frequently in practical engineering,which affects the anti-seepage and stability of dams,and it is of great significance to analyze and study the relevant factors affecting the dam crest cracking for the design and operation of dams.Based on this,by comparing the variation law of deformation gradient of dam crests before and after the cracking of typical dams,the deformation gradient is introduced as an index to analyze the influencing factors of dam crest cracking of high-core rockfill dams.Based on the relevant information of several built high-core rockfill dams,a research scheme considering the size of the dam body,the thickness of the overburden,the height and rate of water storage,and operation time is constructed.The results show that the deformation gradient of dam crest increases significantly with the increase in dam height,and the relationship between them is nonlinear.The dam crest cracking risk of high-core rockfill dams built on deep overburden is greater,but when the overburden thickness reaches more than 100 m,the deformation gradient of dam crests tends to converge.The deformation gradient of dam crests is more sensitive to high water storage level,and the deformation gradient of dam crest increases with the acceleration of water storage rate.