Abstract When the shield tunnel in the sandy gravel mudstone composite stratum under-crosses the expressway, it is easy to cause a large settlement of the expressway pavement above. In order to ensure the safety and the comfort of driving on the expressway, grouting in the tunnel is widely used on the site to reinforce the soil around the tunnel, so as to control the land subsidence. Therefore, it is very important to study the grouting reinforcement range in the tunnel when the shield tunnel in the sandy gravel mudstone composite stratum under-crosses the expressway. By taking the tunnel of the Gaobeiba entrance-exit section of Chengdu Rail Transit Line 30 as the research case, the grouting reinforcement range when the shield tunnel under-crosses the expressway under different stratum composite ratios is studied by using the three-dimensional numerical calculation method. By taking land subsidence as the main evaluation indicator, the effects of various reinforcement schemes under different stratum composite ratios are compared and demonstrated, and the numerical calculation results are compared and analyzed with the field measured data. The results show that: (1) The stratum composite ratio has a significant influence on the maximum value of land subsidence, the range of subsidence influence and the manifestation form of the subsidence curve; (2) Land subsidence amount caused by shield tunneling is negatively correlated with the stratum composite ratio β, but not obviously correlated with the surface uplift amount; (3) When the stratum composite ratio β is determined, from the point of view of controlling land subsidence, the effect of increasing the radial reinforcement depth of the stratum is better than that of expanding the circumferential reinforcement angle.
Abstract：
When the shield tunnel in the sandy gravel mudstone composite stratum under-crosses the expressway, it is easy to cause a large settlement of the expressway pavement above. In order to ensure the safety and the comfort of driving on the expressway, grouting in the tunnel is widely used on the site to reinforce the soil around the tunnel, so as to control the land subsidence. Therefore, it is very important to study the grouting reinforcement range in the tunnel when the shield tunnel in the sandy gravel mudstone composite stratum under-crosses the expressway. By taking the tunnel of the Gaobeiba entrance-exit section of Chengdu Rail Transit Line 30 as the research case, the grouting reinforcement range when the shield tunnel under-crosses the expressway under different stratum composite ratios is studied by using the three-dimensional numerical calculation method. By taking land subsidence as the main evaluation indicator, the effects of various reinforcement schemes under different stratum composite ratios are compared and demonstrated, and the numerical calculation results are compared and analyzed with the field measured data. The results show that: (1) The stratum composite ratio has a significant influence on the maximum value of land subsidence, the range of subsidence influence and the manifestation form of the subsidence curve; (2) Land subsidence amount caused by shield tunneling is negatively correlated with the stratum composite ratio β, but not obviously correlated with the surface uplift amount; (3) When the stratum composite ratio β is determined, from the point of view of controlling land subsidence, the effect of increasing the radial reinforcement depth of the stratum is better than that of expanding the circumferential reinforcement angle.
LIU Bin1 ZHAO Dongping2,
3 LI Dong3
.Study on Grouting Reinforcement Range of Shield Tunnel Undercrossing Expressway in Composite Stratum[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(6): 187-196
2022, Vol. 59 