New sheet piled retaining wall in front of existing
Client: Tameside Metropolitan Borough Council
- Mossley Sewage Works Retaining Wall supports the A635 Manchester Road above Mossley Sewage Works. The wall was in a very poor condition with significant settlement and bulging.
- The design of a strengthening scheme was particularly challenging due to the presence of a large diameter sewer running parallel and passing underneath the wall into the sewage works. The design was further complicated as a strengthening solution needed to be developed that ensured that the existing wall would not collapse during construction and allow the work to be undertaken in a small strip of land at the foot of the wall without encroaching onto land owned by United Utilities. Ground conditions were also found to be poor with what appeared to be an infilled valley passing under the wall at the position of worst bulging.
- The strengthening scheme consisted of installing sheet piles in front of the existing wall and backfilling between the back of the sheet pile and existing wall with mass concrete where the wall was at risk of imminent collapse. The remaining length of wall was grouted and soil nailed. The embedded length of the sheet pile was reduced where it passed over the sewer, in agreement with United Utilities, and walings installed to distribute the load back to the full length piles.
- The sheet piles were clad with random coursed masonry to match the existing wall construction.