水电站洞群模型试验中位移量测方法的应用研究

岩土工程物理模型试验是一种重要的工程稳定研究的模拟方法，与数值分析方法相比，除了能较好地模拟施工过程和对洞群稳定性的影响之外，更重要的是能够模拟出围岩破裂的形态和过程。但是许多制约因素使得这类试验难以达到预期效果，其中包括试验过程中物理量的量测问题。本文以双江口水电站洞群大型三维模型试验为研究对象，为解决洞周围岩和边墙关键点微小位移的量测问题，在试验开挖过程中采用了数字照相变形量测技术和基于光纤布拉格光栅(FBG)的特殊棒式位移传感器，并研制了以高精度光栅尺为传感器的微型多点位移计监测做记录。经计算分析后，可获得洞室在加载与开挖过程中的洞室围岩和边墙关键点位移的变化过程与规律曲线。研究结果表明：多种量测方法在洞周围岩和边墙关键点位移量测方面的应用和研究取得了令人满意的效果。

Study on the Displacement Measurement Methods for 3D Geo-mechanical Model Test of Underground Hydropower Station

The Shuangjiangkou hydropower station with a maximum output of 2000 MW is located on the Dadu River in Sichuan Province in China. From the in situ rock stress measurement, the maximum principal stress near the underground cavern complex is up to 38MPa. The high in situ stress is absolutely rare in Chinese hydropower stations. As a result, a 3D geo-mechanical model test was presented to research the stability of the underground cacavern group. The study was mainly focus on the displacement measurement techniques which are the Fiber Bragg Grating (FBG) sensing bar, the high-accuracy mini extensometers measuring system and digital photography-based deformation measurement technique (DPDM). These techniques can real-time measure the deformation and displacement of the surrounding rock masses during the excavation. This research obtained the expected effects and provided guidance for the design and construction of the power station.