Unloading break of hard rock under high geo-stress condition:inner cracking observation for the basalt in the Baihetan's underground powerhouse

被引：0
|
作者：
Jiang Q. [1 ]
Fan Y. [2 ]
Feng X. [1 ]
Li Y. [2 ]
Pei S. [1 ]
Liu G. [1 ]
机构：
[1] State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, Hubei
[2] China Three Gorges Project Corporation, Beijing
来源：
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | 2017年 / 36卷 / 05期
基金：
中国国家自然科学基金; 国家重点研发计划;
关键词：
Digital borehole camera; High geo-stress; Rock break; Rock mechanics; Time dependent cracking; Underground powerhouse; Unloading excavation;
D O I：
10.13722/j.cnki.jrme.2016.1112
中图分类号：
学科分类号：
摘要：
The spalling of hard basalt is one of the serious geotechnical problems in the underground powerhouse of the Baihetan hydropower station. The paper presented the general inner cracking process captured by the digital borehole camera and the detailed in-situ failure proofs during the unloading excavation. These study showed that the spalling, with the sheet and plate shape, happened not only to the intact basalt, but to the basalt with a few joints. Further optical scanning and scanning electron microscope observations indicated that the break surface of the spalling rock was rough and belong to the tensional failure mode. The field digital borehole camera observation in the underground powerhouse indicated that the basalt spalling had the characteristics of spatial discontinuous distribution, time-dependent increase of cracking depth, increase and decrease of crack's width, obvious restraining effect of rock bolt and anchor cable. What's more, the case study also indicated that the inner crack and surface failure of basalt related to each other, namely, the surface failure happened when the inner cracks developed sufficiently. These knowledge about the basalt spalling provided us not only the visual picture of basalt's break, but also a guide for disaster warning and supporting optimization in the deep rock engineering. © 2017, Science Press. All right reserved.
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页码：1076 / 1087
页数：11
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