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| Discussion on the Several Key Design Problems for A Foreign Railway Tunnel Project |
| HAN Hua-xuan |
| (China Railway Design Corporation, Tianjin 300251, China) |
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Abstract Abstract：Research purposes： The design of a railway tunnel project in a foreign country have faced several engineering problems such as standardizing the pressure calculation and the design basis of tunnel reinforcement measures for the surrounding rock pressure within volcanic ash layer and the swelling soil stratum, standardizing the seismic design basis of tunnel within high intensive seismic area, optimizing the selection method of service gallery under short construction period. The main purpose of the study is how to adopt China design standards as design basis and adjust details with local conditions to formulate appropriate technical standards and engineering countermeasures. Research conclusions： (1) Plastic design theory was adopted to determine the surrounding rock pressure around tunnel within volcanic ash layer. Forecast on swelling force shall refer to the ratio of displacement and stress relief during tunnel excavation. (2) Comprehensive measures were used to pre-reinforce the tunnel within weak stratum formed by volcanic ash, by applying chemical churning piles, dewatering and discharging measures in both inside and outside tunnel. (3)Response displacement method and Level I, II performance-based design method was applied on seismic performance verification of tunnel structure. The region that requires seismic precaution was determined based on overburden depth and local geological structure, with corresponding precaution measures applied such as ground grouting, structure reinforcement and joints optimizing. (4) Scheme comparison was used to optimize the form of service gallery, by considering technology, economy issues and applicability. (5) The research results can provide guidance for other overseas tunnel design projects or within soft soil stratum and high intensive seismic area.
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Received: 04 July 2017
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2017, Vol. 34 
