Deep Fracturing of the Hard Rock Surrounding a Large Underground Cavern Subjected to High Geostress: In Situ Observation and Mechanism Analysis

doi:10.1007/s00603-017-1220-4

CORC > 武汉岩土力学研究所 > 中科院武汉岩土力学所 > 岩土力学所知识全产出 > 期刊论文

	Deep Fracturing of the Hard Rock Surrounding a Large Underground Cavern Subjected to High Geostress: In Situ Observation and Mechanism Analysis
	Li, Shao-Jun 2; Feng, Xia-Ting1,2 ; Pei, Shu-Feng 2,3; Jiang, Quan 2; Zhou, Yang-Yi 1; Yao, Zhi-Bin 1
刊名	ROCK MECHANICS AND ROCK ENGINEERING
	2017
卷号	50 期号:8 页码:2155-2175
关键词	Underground cavern High geostress Deep fracturing Borehole camera Joints Stress concentration Fracturing mechanism
ISSN号	0723-2632
DOI	10.1007/s00603-017-1220-4
英文摘要	Rocks that are far removed from caverns or tunnels peripheries and subjected to high geostress may undergo 'deep fracturing'. Deep fracturing of hard rock can cause serious hazards that cause delays and increase the cost of construction of underground caverns with high sidewalls and large spans (especially when subjected to high geostress). To extensively investigate the mechanism responsible for deep fracturing, and the relationship between fracturing and the excavation & support of caverns, this paper presents a basic procedure for making in situ observations on the deep fracturing process in hard rock. The basic procedure involves predicting the stress concentration zones in the surrounding rocks of caverns induced by excavation using geomechanical techniques. Boreholes are then drilled through these stress concentration zones from pre-existing tunnels (such as auxiliary galleries) toward the caverns before its excavation. Continuous observations of the fracturing of the surrounding rocks are performed during excavation using a borehole camera in the boreholes in order to analyze the evolution of the fracturing process. The deep fracturing observed in a large underground cavern (high sidewalls and large span) in southwest China excavated in basalt under high geostress is also discussed. By continuously observing the hard rock surrounding the arch on the upstream side of the cavern during the excavation of the first three layers, it was observed that the fracturing developed into the surrounding rocks with downward excavation of the cavern. Fracturing was found at distances up to 8-9 m from the cavern periphery during the excavation of Layer III. Also, the cracks propagated along pre-existing joints or at the interfaces between quartz porphyry and the rock matrix. The relationship between deep fracturing of the surrounding rocks and the advance of the cavern working faces was analyzed during excavation of Layer Ib. The results indicate that the extent of the stress relief zone is about 7 m if footage of 3 m is adopted for the rate of advance of the cavern faces. An analysis of the effects of the initial geostress and evolving stress concentration on deep fracturing was also made. It could be concluded that the deep fracturing of the rocks in the upstream side of the cavern is caused by the combined effect of the high initial geostress, the transfer of the stress concentration zone toward the deep surrounding rocks, and the occurrence of discontinuities.
WOS研究方向	Engineering ; Geology
语种	英语
出版者	SPRINGER WIEN
WOS记录号	WOS:000407321700013
内容类型	期刊论文
源URL	[http://119.78.100.198/handle/2S6PX9GI/4111]
专题	岩土力学所知识全产出_期刊论文岩土力学所知识全产出国家重点实验室知识产出_期刊论文
作者单位	1.Northeastern Univ, Minist Educ Safe Min Deep Met Mines, Key Lab; 2.Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn ; 3.Univ Chinese Acad Sci
推荐引用方式 GB/T 7714	Li, Shao-Jun,Feng, Xia-Ting,Pei, Shu-Feng,et al. Deep Fracturing of the Hard Rock Surrounding a Large Underground Cavern Subjected to High Geostress: In Situ Observation and Mechanism Analysis[J]. ROCK MECHANICS AND ROCK ENGINEERING,2017,50(8):2155-2175.
APA	Li, Shao-Jun,Feng, Xia-Ting,Pei, Shu-Feng,Jiang, Quan,Zhou, Yang-Yi,&Yao, Zhi-Bin.(2017).Deep Fracturing of the Hard Rock Surrounding a Large Underground Cavern Subjected to High Geostress: In Situ Observation and Mechanism Analysis.ROCK MECHANICS AND ROCK ENGINEERING,50(8),2155-2175.
MLA	Li, Shao-Jun,et al."Deep Fracturing of the Hard Rock Surrounding a Large Underground Cavern Subjected to High Geostress: In Situ Observation and Mechanism Analysis".ROCK MECHANICS AND ROCK ENGINEERING 50.8(2017):2155-2175.