Abstract:

Grouting is an effective method for strengthening stratum and sealing water during tunneling in waterrich, loose, soft and fractured strata. Many projects show that the strengthening length by stepped and onwards grouting method is 30m, as a result of the influence of grouting holes collapse and other factors, the grouting and. For the strengthened 30m, the grouting effect of the front 15m is well, but the latter 15m is poor. In addition, this grouting method has low construction efficiency and high cost and needs repeating grouting. Hence, an integrated technology of drilling and grouting is introduced in this paper. Retrograde and stepped grouting is realized by sealing grouting holes. The grout can discharge from the aiguilles and run into the area need grouting directly, so the integrated construction of drilling and grouting is achieved. This technology can reduce transition time among construction procedures, advance grouting efficiency and improve grouting effects.

Key words: tunnel, drilling, grouting, integrated construction technology, retrograde and stepped grouting