From RiverLinx news (pls refer to the link below for photos):

Riverlinx CJV, a joint venture between BAM Nuttall, Ferrovial Construction and SK Ecoplant working on behalf of Transport for London, are committed to minimising road use and using the river for transport where possible whilst building the Silvertown Tunnel. We have now started removing beneficial reuse excavated material by barge, following a major upgrade of the facilities at Thames Wharf in Silvertown, to enable safe mooring and loading.

Our first barge as part of this upgrade was received at the start of February and this method of transportation will transport at least 55 per cent of all beneficial reuse excavated materials associated with the project by river, considerably reducing the total number of lorry movements. Since the Silvertown Tunnel project started more than 150,000 tonnes of materials and waste have been delivered or removed from site by river transport.

At full capacity – up to four barges per day will be used. Some deliveries will still need to be made by road, but all vehicles used by the project meet the highest emissions standard (Euro VI) and are ULEZ compliant.

To facilitate the movement of beneficial reuse excavated material from site to barge, a conveyor structure has been built to mechanise the movement of excavated materials. When tunnelling begins in summer 2022, the system will also be used to move excavated material from the launch chamber to Thames Wharf, ready for removal at high tide.  

https://www.riverlinx.co.uk/news/riverlinx-starts-transporting-waste-by-barge