Diaphragm Walls Extreme â€“ Contrast Between Going Deep and Getting Small-Paper

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The paper examines two opposing demands shaping diaphragm-wall technology: reaching unprecedented depths and operating in increasingly confined urban spaces. Diaphragm walls are used for retaining structures, foundations, groundwater barriers, and, more recently, deep bulk sampling. Their adaptability to varied soils and rock makes them suitable for both challenges.<br /><br />Construction typically involves site preparation, guide walls, pre-excavation, cutter excavation under stabilizing fluid, trench cleaning, reinforcement installation where required, and concreting. Digital monitoring and data transfer support quality control, equipment coordination, and project planning.<br /><br />Deep applications include Shanghai’s Yunlingxi shaft, where test panels reached 150 m and met strict verticality requirements, and a Canadian mine-sampling project that reached a record 251.1 m. The latter demonstrated that trench cutters can repeatedly excavate beyond 220 m and recover samples under demanding conditions.<br /><br />At the opposite extreme, projects in Hong Kong and Paris show how specialized low-headroom carriers and compact cutters can work around existing structures, limited access, and hard ground. Examples include work beneath structures as low as 5.8–6.5 m and a compact cutter excavating limestone to depths exceeding 60 m.<br /><br />Future development is expected to further reduce machine dimensions and environmental impacts. Prototypes are being explored for diaphragm-wall construction from underground spaces such as tunnels, with systems potentially less than 3 m high and wide while still cutting to about 40 m. Electrification and measures to reduce noise and vibration are also anticipated.<br /><br />The paper concludes that continued innovation in equipment, methods, digital systems, and emissions reduction will make diaphragm-wall construction possible in deeper, tighter, and more environmentally sensitive settings.

Keywords

diaphragm wall

deep excavation

urban construction

trench cutter

groundwater barrier

verticality control

digital monitoring

low-headroom equipment

deep sampling

electrification