报告题目：Artificial Ground Freezing: transforming construction processes in underground engineering

报告人：英国剑桥大学Giulia Viggiani教授

讲座时间：2024年6月21日（星期五）15:30-18:30

讲座地点：学院粤海校区（南区）致理楼L1-1007会议室

报告人简介：

Giulia Viggiani joined the Department of Engineering at the University of Cambridge as Professor of Infrastructure Geotechnics in 2017. Before this, she was Full Professor of Geotechnics at Università di Roma Tor Vergata. She has a Laurea in Civil Engineering from Università di Napoli Federico II and a PhD in Geotechnical Engineering from the City University in London. She has been Scientific Visitor at the Max Planck Institute for Mathematics in the Sciences, in Leipzig, MTS Visiting Professor of Geomechanics at the University of Minnesota, and Academic Visitor at Imperial College, working on the JLE-Link Project. She currently chairs ISSMGE TC204 – Underground Construction in Soft Ground.

The main thrust of her research is on the applications of soil mechanics to geotechnical engineering, and deals mainly with underground construction, foundation engineering, and earthquake geotechnical engineering. She has been involved in many infrastructural projects in Italy and the UK, including, e.g., monitoring building response to construction of the Jubilee Line Extension in London, the design and construction of Lines 1 and 6 of Napoli underground and of Line C of Roma underground, and the design of the foundations, anchor blocks and terminal structures of the Strait of Messina Bridge. She has carried out original research on tunnelling and construction processes, tunnelling induced damage assessment and connected mitigation and remedial measures, and performance based design of geotechnical structures under seismic actions, using a combination of field monitoring and laboratory observations, theoretical analyses, and physical and numerical modelling. Part of her research is also devoted to topics in fundamental soil mechanics, such as the mechanical behaviour of freezing ground and of granular materials with crushable grains.

报告摘要：

The use of Artificial Ground Freezing (AGF) to form earth support systems has had applications worldwide. These cover a variety of construction problems, including the formation of frozen earth walls to support deep excavations, structural underpinning for foundation improvement, and temporary control of ground water in construction processes. The lecture will describe an extensive and successful application of AGF during excavation of some of the stations of Line 1 of Napoli Underground through loose granular soils and a fractured soft rock. Construction was accompanied by an intense programme of monitoring designed to measure and control the effects on adjacent structures, which, for its extension and completeness, represented a unique opportunity to collect field data on the performance of AGF. The lecture describes the main phenomena that were observed during construction, and some of the analyses that were carried out to interpret different aspects of the process, such as de-coupled heat propagation and mechanical analyses of the interaction between the frozen ring and the surrounding soil. The successful application of AGF in this and other similar projects in Italy has transformed attitudes in the practice with a growing awareness of its merits as a temporary ground improvement system with minimal environmental impact. Experience has also demonstrated that, although at first impression it may appear costly, in many cases, AGF is competitive with more conventional ground improvement, support, and de- watering systems.