中文摘要：

在建的金沙江白鹤滩水电站地下厂房开挖规模巨大,其复杂地质条件和高应力导致围岩破坏现象突出。针对左、右厂房第一层开挖过程中曾频繁遭遇到的围岩片帮破坏问题,结合地质、施工、测试、试验及数值分析资料,全面总结和深入分析玄武岩片帮机制。首先,归纳和总结地下厂房围岩片帮破坏的基本特征与规律,包括其表现形式、形态特征、空间位置、破坏规模、滞后规律、破坏发展特征、对应岩性及支护特征等主要信息;进而重点探讨厂区地应力、岩体结构、岩性、施工因素等对围岩片帮的影响规律;最后,综合分析揭示片帮的形成与发生机制。该研究可为白鹤滩水电站地下厂房后续开挖过程中围岩片帮破坏的预防和调控提供重要支撑,也可为同类高地应力条件下大型地下洞室类似围岩破坏的防控提供参考。

英文摘要：

The underground powerhouse caverns of hydropower station at Baihetan of Jinsha river is under construction currently and is large in size and complex in geological environment. Spalling failure of local surrounding rock occurred frequently in the excavation of the first layer of the left and right powerhouse. An overall summary and a deep analysis of the mechanism of rock spalling failure in basalts was made combined with the geological,construction,testing,experimental and numerical data. Firstly,the characteristics and laws of spalling failure,including the failure forms,the morphological characteristics,the spatial location,the scale of destruction,the lagging,the failure development process,the lithology and the support status were summarized. Secondly,the influence of the geo-stress,rock structure,lithology,construction factors on the surrounding rock failure were fully discussed. Finally,comprehensive analyses were made to reveal the mechanisms of spalling failure.