Geological Investigation and Tunnel Excavation Aspects of the Weakness Zones of Xiang’an Subsea Tunnels in China

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• 作者：Peixin Shi ; Dingli Zhang ; Jianli Pan ; Wei Liu
• 关键词：Subsea tunnel ; Weakness zone ; Excavation stability ; Water ingress ; Pre ; investigation ; Pre ; grouting
• 刊名：Rock Mechanics and Rock Engineering
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：49
• 期：12
• 页码：4853-4867
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geophysics/Geodesy; Civil Engineering;
• 出版者：Springer Vienna
• ISSN：1434-453X
• 卷排序：49

文摘

Tunneling through weakness zones under deep seawater involves significant risks and may have disastrous consequences. This paper presents a case study of geological investigation and excavation aspects of subsea tunnels in major weakness zones. The subject is the Xiang’an subsea tunnels, the first subsea tunnel project in mainland China. The Xiang’an subsea tunnels passed through four major weakness zones, mainly consisting of highly to completely weathered rock mass. The weakness zones were characterized by a combination of long-distance and short-distance, destructive and nondestructive methods, which supplement and verify information with each other. The weakness zones were treated by full-face curtain grouting, using both cementitious and chemical grouts. The interrelationship between the settlement at tunnel crown and ground surface, as well as the interrelationship between ground settlement and ground cracking, were explored based on instrumentation data recorded during tunneling on land. The pre-warning, warning, and limiting values of tunnel crown settlement during excavation of each heading of subsea sections were established to protect the seabed against cracking. Engineering means and methods were developed to control the ground deformation during excavation.