Experimental study of the comprehensive technology of grouting and suspension under an operating railway in the cobble stratum

Abstract

The construction technology of shield tunnelling under an operating railway in an adverse stratum is complex and risky. The existing research results mostly focus on the settlement control of the tunnel under the existing structure, but they are not adequate to provide a systematic reference for shield tunnelling under an operating railway with strict requirements on the settlement control. Based on the background of the Luoyang Rail Transit Line 2 shield passing through the Luoyi Railway, the comprehensive technology of grouting and suspension (CTGS) has been proposed, and field test and numerical simulation are used to study the effects of its application. The results show that the comprehensive technology of grouting and suspension has a significant effect on the rail settlement control of shield tunnelling under the operating railway in a cobble stratum. Using the grouting method to grout subgrade soil can improve the strength of the overlying soil layer. Using the suspension method to suspend the railway tracks can directly transfer the load to the pile foundation to avoid the subgrade bearing excessive load. CTGS combines the grouting method with the suspension method, which can be used as the preferred technology to control the influence of subgrade soil settlement on railway track surface. Compared with the similar technology, although the project cost is slightly higher, CTGS significantly ensures railway safety during the construction process, which can help keep the railway operation free from interference during the construction period and has obvious comprehensive benefits. CTGS has an important reference value for the safety control of shield tunnelling construction with the risky source under adverse geological conditions such as a sandy cobble stratum.