黄藏寺水利枢纽坝前H8堆积体稳定性分析

Stability analysis of H8 accumulation body in front of Huangzangsi hydro-complex

根据黄藏寺水利枢纽工程的前期勘测成果,H8堆积体分为Ⅰ区、Ⅱ区和Ⅲ区。几十年来Ⅰ区的前缘受河水冲刷,处于缓慢蠕动变形阶段,Ⅱ区和Ⅲ区处于稳定状态。自2016年工程开工,大坝的施工严重影响了H8堆积体的稳定,直接导致Ⅰ区在短期内产生滑坡,Ⅱ区和Ⅲ区暂稳定。通过现场实时调查及变形监测发现,Ⅰ区经历了Ⅰ_1区蠕动~Ⅰ_1区滑动~Ⅰ_1+Ⅰ_2滑动3个动态变化过程。结合实际揭露的滑动面特征和反演计算,确定符合实际的滑动面参数,对H8堆积体Ⅰ区的稳定性进行数值模拟计算,分析了Ⅰ区产生滑坡的原因,并提出了相应的治理措施。该研究可为H8堆积体后期的综合治理提供可靠的地质技术支持,为类似大型水利枢纽工程坝前堆积体的防治提供重要的施工经验。

According to the pre - phase survey results of the Huangzangsi water conservancy project, H8 accumulation body, located in front of the dam, was divided into area Ⅰ , area Ⅱand area Ⅲ. In recent decades, the area Ⅰ was in a stage of slow creep deformation for its front edge was scoured by the river and areas Ⅱand Ⅲ were in a stable state. Since the commencement of the project in 2016, the dam construction has seriously affected the stability of H8 accumulation body. As a result, a landslide had occurred in area I in a short - term, area Ⅱ and Ⅲ are still in a stable state. Through real - time field investigation and deformation monitoring, it was found that the area Ⅰ had undergone three dynamic val7 processes of area Ⅰ 1 creep, area Ⅰ 1 sliding, area Ⅰ 1 ＋ Ⅰ2 sliding. Combined with the actual sliding surface characteristics and inversion calculation, the actual sliding surface parameters were determined, and the stability of area I of H8 accmnulation body was nmnerically simulated. On this basis, we analyzed the sliding causes for the area Ⅰ and put forward several corresponding control measures. The study can provide reliable geotechnical support for the comprehensive control of H8 accmnulation body in later period and important construction experience for the prevention and treatment of accmnulation body at dam front for similar large - scale water conservancy projects.