Abstract The shield construction method has been widely used in the construction of urban rail transit tunnels in China, and the problem of failures in shield tunnel segments has also been attracting increasing attention. This paper draws a development map of the segment damage failures based on the sudden segment damage event in a shield tunnel under construction, analyzes the relevant documentation and test data, clarifies the cause mechanism of the failures, formulates and implements corresponding treatment measures. The analysis results show that extensive cavities behind the segment lining would lead to the insufficient constraint on the tunnel structure by the surrounding rocks, and further cause the bending-torsion failure similar to the compression rod structure when the formed tunnel is subject to the action of the thrust and torque of the shield machine, the buoyancy of the synchronous injection grouts, as well as the soil and water pressure and torque of the cutterhead, which is the main cause of the segment damage failure; The monitored tunnel deformation data show that the two-stage treatment measure of "backfill grouting + repair of damaged parts" could achieve good results. In the process of shield driving, the quality of synchronous grouting should be strictly managed to prevent the shield tunnel segment cracking and fracturing failures induced by deviation from the tunnel axis .
Abstract：
The shield construction method has been widely used in the construction of urban rail transit tunnels in China, and the problem of failures in shield tunnel segments has also been attracting increasing attention. This paper draws a development map of the segment damage failures based on the sudden segment damage event in a shield tunnel under construction, analyzes the relevant documentation and test data, clarifies the cause mechanism of the failures, formulates and implements corresponding treatment measures. The analysis results show that extensive cavities behind the segment lining would lead to the insufficient constraint on the tunnel structure by the surrounding rocks, and further cause the bending-torsion failure similar to the compression rod structure when the formed tunnel is subject to the action of the thrust and torque of the shield machine, the buoyancy of the synchronous injection grouts, as well as the soil and water pressure and torque of the cutterhead, which is the main cause of the segment damage failure; The monitored tunnel deformation data show that the two-stage treatment measure of "backfill grouting + repair of damaged parts" could achieve good results. In the process of shield driving, the quality of synchronous grouting should be strictly managed to prevent the shield tunnel segment cracking and fracturing failures induced by deviation from the tunnel axis .
HE Leiming1 DENG Feifan2,
3 JIA Peng2,
3
.Causes and Treatment Measures of Sudden Segment Damage Failures in a Shield Tunnel under Construction[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(1): 225-231
2022, Vol. 59 