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Influence of Tectonic Characteristics of Surrounding Rocks on Engineering Geology of Water Conveyance Tunnel in the Hanjiang-to-Weihe River Valley Water Diversion Project
(1 State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi ′an 710069; 2 China Railway First Survey and Design Institute Group Co., Ltd., Xi′an 710043; 3 Hanjiang-to-Weihe River Valley Water Diversion Project Construction Co., Ltd., Shaanxi Province, Xi′an 710010; 4 Institute of Geotechnical Engineering, Xi′an University of Technology, Xi′an 710048)
Abstract The water conveyance tunnel of the Hanjiang-to-Weihe River Valley Water Diversion Project, which crosses the Qinling Mountains, is a key section that affects the overall progress of the Project. The complex lithology and tectonic characteristics of the Qinling Orogenic Belt have a huge impact on the construction and maintenance of the water conveyance tunnel. An in-depth geological analysis of the tentonic characteristics of the tunnel surrounding rocks can provide an important geological basis for the construction of the Project. Based on field geological work, this paper combines microscopic observation of typical rock sample slices and rock mechanics tests to obtain the tectonic data and mechanical properties of the surrounding rocks in the South Qinling section. The South Qinling section can be divided into four lithological sections according to the macro and micro tectonic characteristics of the surrounding rocks: gneisses section of upper amphibolite facies, metamorphic rock section of lower amphibolite facies, epimetamorphic rock section and granite section. The deformed structure that affects and constrains the engi? neering characteristics of the surrounding rocks can be further divided into two categories: one is the surrounding rocks that develop brittle deformation, which are affected by the intracontinental tectonic evolution since the Middle Cenozoic with the brittle deformation extremely developed and have the most intuitionistic and obvious impact on the project construction. The other is the surrounding rocks with weak structural surfaces, which causes the mechanical properties of the whole rock mass to have significant anisotropy, and the relationship between the occurrence of weak structural surfaces and the orientation of principal stress governs the mechanical properties of the surrounding rocks.
Abstract：
The water conveyance tunnel of the Hanjiang-to-Weihe River Valley Water Diversion Project, which crosses the Qinling Mountains, is a key section that affects the overall progress of the Project. The complex lithology and tectonic characteristics of the Qinling Orogenic Belt have a huge impact on the construction and maintenance of the water conveyance tunnel. An in-depth geological analysis of the tentonic characteristics of the tunnel surrounding rocks can provide an important geological basis for the construction of the Project. Based on field geological work, this paper combines microscopic observation of typical rock sample slices and rock mechanics tests to obtain the tectonic data and mechanical properties of the surrounding rocks in the South Qinling section. The South Qinling section can be divided into four lithological sections according to the macro and micro tectonic characteristics of the surrounding rocks: gneisses section of upper amphibolite facies, metamorphic rock section of lower amphibolite facies, epimetamorphic rock section and granite section. The deformed structure that affects and constrains the engi? neering characteristics of the surrounding rocks can be further divided into two categories: one is the surrounding rocks that develop brittle deformation, which are affected by the intracontinental tectonic evolution since the Middle Cenozoic with the brittle deformation extremely developed and have the most intuitionistic and obvious impact on the project construction. The other is the surrounding rocks with weak structural surfaces, which causes the mechanical properties of the whole rock mass to have significant anisotropy, and the relationship between the occurrence of weak structural surfaces and the orientation of principal stress governs the mechanical properties of the surrounding rocks.
ZHANG Jie1 LI Wei1 LI Limin2 WAN Jiwei3 DING Weihua4 JIA Chao1
.Influence of Tectonic Characteristics of Surrounding Rocks on Engineering Geology of Water Conveyance Tunnel in the Hanjiang-to-Weihe River Valley Water Diversion Project[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(3): 23-32
2021, Vol. 58 