In 1814 engineer Marc Brunel proposed a plan to construct a tunnel in St Petersburg under river Neva. This proposal was turned down and a bridge constructed instead. Brunel did not give up the idea. He continued to work on his idea for new technique of tunnelling. In 1918, Thomas Cochrane and Brunel combined efforts to patent the tunnelling shield. This was a revolutionary advancement in the tunnelling technology. In 1823 Brunel came up with a plan to construct a tunnel between Wapping and Rotherhithe. This was to be dug with the use of a new shield.
Private investors such as the Duke of Wellington owned up to finance the project. A theme Tunnel company was later formed in 1824. The project was kick started in 1825. The first phase involved constructing a large shaft on the Rotherhithe’s South bank. This was approximately 46m (150 feet back from the Thame river bank. To dig the shaft, an iron ring 15 m (50 feet) was assembled in a diameter above the ground level. A brick wall 12 m (40 feet) high and 91 cm (3 feet) thick was constructed on top of this (see figure 01).
Figure 01 A powerful steam engine was used to surmount it and to drive the pump of the excavation. The entire apparatus weight 1,000 tons. The soil under the sharp lower edge of the ring was manually removed by Brunel’s workers. This caused the entire shaft to gradually sink under its weight. It sliced through the soft ground. At one time during the sinking of the shaft, it was stack underground with the pressure around the earth holding it firmly.
There was need for the extra weight to help push the shaft to descent. To descent it further, 50,000 more bricks were temporarily added. It was later revealed that this problem was caused by shaft’s sides being parallel. Years later the Wapping shaft was constructed with a slightly wider bottom. The non-cylindrical tapering design helped prevent the shaft from being stuck. The Rotherhithe shaft had been completed by November 1825. This way, the tunnelling work could start. Brunel’s key construction of the Tunnel was the tunnelling shield put up at Henry Lambeth works.
The mode by which the Thames Tunnels was accomplished made it to be regarded as a shield consisting twelve frames that lie close to each other, and divided into three stories or stages. This way, it had 36 chambers of cell with each cell open to the rear and for one workman. It had moveable boards closing its ends (Will 14). The front part of the tunnel was put against the earth, and the workman, after having removed the one board could excavate the earth behind the depth.
Teape, H. Thames Tunnel Company. Thames Tunnel Company, incorporated 1824. Harvard University. 2007
Richard Beamish, & Marc Isambard Brunel. Notice Concerning the Thames Tunnel. The Institution,
Thames Tunnel Company. The origin, progress and present state of the Thames tunnel and the advantage likely to accrue from it, both to the proprietors and to the public. London: E. Wilson, 2007.
Will, Howie. Thames Tunnel to Channel Tunnel: 150 Years of Civil Engineering : Selected Papers from the Journal of the Institution of Civil Engineers Published to Celebrate Its 150th Anniversary. London: Thomas Telford, 1987. 2008.