Preliminary study on determination of reasonable ratio of spacing to diameter of double tunnels under earthquake

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	Preliminary study on determination of reasonable ratio of spacing to diameter of double tunnels under earthquake
	Zhou Yongqiang; Sheng Qian; Leng Xianlun; Fu Xiaodong; Li Nana
	2017
会议日期	MAR 11-12, 2017
会议地点	Zhuhai, PEOPLES R CHINA
关键词	earthquake reasonable ratio of spacing to diameter double tunnels relative displacement plastic zone
卷号	129
页码	1-8
英文摘要	For determining the reasonable ratio of spacing to diameter of double tunnels, the criterion is often only for the excavation, and does not take into account the earthquake situation. In order to ensure the stability of surrounding rock masses, safety and economic rationality during construction and operation of the adjacent tunnels, in this paper, the dynamic responses with different spacing under different earthquake actions and different constitutive relations are analyzed. Based on the plastic zone of the inter-tunnel rock mass connecting or not and the inflection point of the relative displacement curve of the key points of the surrounding rock mass of the tunnel, the reasonable ratio of spacing to diameter under earthquake action is preliminarily determined. The results show that the influence of the earthquake on single tunnel is smaller than that on double tunnels, regardless of the distance between the tunnels and the diameter of the tunnel. Under earthquake, the closer the double tunnels are, the relative displacement is larger. When the distance is smaller than the tunnel diameter, the relative deformation is much larger than other cases, when the distance is 2-3 times diameter, the relative deformation is basically maintained at a stable value. For different diameter of tunnels, the reasonable spacing is not the same under excavation, but its reasonable ratio of spacing to diameter is about 1.5, more than 1.5, the plastic zone of the surrounding rock between tunnels will not penetrate. The response trend of the surrounding rock is the same under excavation and earthquake, having nothing to do with the diameter, and its reasonable ratio of spacing to diameter is about between 2 and 3. Compared the reasonable ratio of spacing to diameter under excavation, the reasonable ratio of spacing to diameter under the action of the earthquake is larger, so it needs to determine the reasonable ratio of spacing to diameter in high seismic intensity areas, not only consider excavation, but also consider earthquake. It is hoped that the research can provide some technical reference for practical engineering. With the national economic development and construction, a large number of railway tunnels, highway tunnels, mine tunnels, urban railways and hydraulic tunnels and other projects have been built. In the construction process, due to development needs, it often needs to form two, or even more parallel or cross underground tunnels group. In order to ensure the stability of the surrounding rock masses, safety and economic rationality during construction and operation of the adjacent tunnels, a reasonable spacing should be chosen for different sizes of tunnels. In other words, reasonable ratio of spacing to diameter of tunnels, has become an important and meaningful research topic. For the determination of reasonable ratio of spacing to diameter, it generally uses engineering analogy, numerical method and model test and the corresponding design specifications. The engineering analogy method is the method that, through the statistics of the spacing of the underground caverns, puts forward the suggested value of the spacing of the caverns under the general conditions([1,2]). The numerical method, based on the finite element, the discrete element, the boundary element and other numerical software, and model test are used to calculate and analysis stress, displacement and the corresponding plastic zone of the adjacent caverns at different distances, and a reasonable spacing value with relatively stable influence is obtained ([3-7]). The design specification specifies different types of tunnels: for highway tunnels, "Code for Design of Road tunnels" (JTG_D70/2-2014) specifies the minimum spacing between different separate double tunnels corresponding to different grades of surrounding rock([8]); For the mine tunnel, although there is no corresponding specification, it has formed a reasonable spacing of the tunnel experience method([9]). "Code for Design of Railway tunnels" (TB-10003-2016) has also made the corresponding minimum spacing between adjacent single-track railway tunnels, and has also established a reasonable distance between adjacent single-track railway tunnels([10]). In order to ensure the stability of rock mass between adjacent tunnels, it is stipulated that the thickness of the tunnels should not be less than 2 times of the excavated tunnel diameter (or tunnel width) by"Specification for design of hydraulic tunnel"(SL279-2016)([11]). The research results and regulations for determining the minimum spacing or reasonable spacing of tunnels are for the tunnels in the excavation, construction process, operation and other conditions to maintain stability and not in the earthquake and other special circumstances. "Code for Design of Road tunnels" (JTG_D70-2004)([8]) provides that "in areas where the peak ground motion acceleration is greater than 0.15, it is appropriate to conduct seismic strength and stability checking in the selection of small distance tunnels". Therefore, it is necessary to study the reasonable spacing of adjacent caverns for earthquake action. For the dynamic response of double tunnels under earthquake, Wang([12]) discussed the influence of the variation of spacing on the dynamic stress concentration of tunnel surface by incident steady-state P. SV wave and SH-wave. Chen([13]) studied the effect of the obliquely incident SV waveson double caverns in a layered half-space, and the ground displacement responses of the double caverns with different spacing. Zhao([14]) used the damage plasticity model to analyze the seismic response of the underground caverns, and studied the effect of the distance between the chambers on the double-chamber and three-chamber models with soft, medium and hard rock. Although the above studies have analyzed the responses of underground tunnels with different spacing under earthquake action and the reasonable spacing range of different types of lithologic caverns has also been initially determined([14]), but there is no reasonable spacing for the adjacent tunnels with different diameters. Therefore, the basic idea of this paper is to analyze the dynamic response of surrounding rock under earthquake and different constitutive relations for adjacent tunnels with different diameters, and to determine the reasonable ratio of tunnel diameter to diameter.
源文献作者	Jiangsu Univ Sci & Technol, Shanghai Univ Elect Power
会议录	PROCEEDINGS OF THE 2017 6TH INTERNATIONAL CONFERENCE ON ENERGY, ENVIRONMENT AND SUSTAINABLE DEVELOPMENT (ICEESD 2017)
会议录出版者	ATLANTIS PRESS
会议录出版地	PARIS
语种	英语
WOS研究方向	Engineering
WOS记录号	WOS:000414083700001
内容类型	会议论文
源URL	[http://119.78.100.198/handle/2S6PX9GI/4924]
专题	岩土力学所知识全产出_会议论文国家重点实验室知识产出_会议论文
作者单位	Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn
推荐引用方式 GB/T 7714	Zhou Yongqiang,Sheng Qian,Leng Xianlun,et al. Preliminary study on determination of reasonable ratio of spacing to diameter of double tunnels under earthquake[C]. 见:. Zhuhai, PEOPLES R CHINA. MAR 11-12, 2017.