Abstract: This article presents a deep excavation support project in Changzhou. The design and application of a series of green excavation support technologies, such as, SMW construction method, soil mixing columns with hot rolled steel inclusions and its installation are introduced. The integration consideration of engineering geological conditions, deep excavation safety, construction schedule, environmental protection, energy saving and emission reduction, economy and other requirements are also presented. The design aspects of large span and two-way steel combination support, flexible excavation support sequence, and demolishing of the supporting structure are thoroughly discussed in the paper. Combined with theoretical calculation and engineering implementation effect, the SMW construction method with large span steel combination support system can ensure the safety operation and use of the surrounding utilities, roads and buildings while ensuring the safety of the excavation itself. The relevant technical aspects and measures can play a valuable reference role for similar projects.

Key words: Deep Excavation Support, Green Technology, Long-Span Two-Way Staggered Steel Composite Support