长距离小间距管廊施工对既有区间盾构隧道的影响

The influence of long-distance and small-spacing pipe gallery construction on existing section shield tunnels

为研究长距离小间距管廊基坑开挖对盾构隧道的变形影响,依托深圳地铁12号线管廊共建工程,利用数值模拟软件模拟综合管廊开挖,研究管廊开挖宽度为10.5 m,开挖深度为6.5 m的工况下,不同管廊开挖长度对盾构隧道的影响。研究不同的分仓开挖步距、钻孔灌注桩嵌固深度、注浆层厚度对隧道变形的影响。结果表明:综合管廊开挖引起下方隧道的变形随着开挖长度的增加而增大,当开挖长度大于3倍开挖宽度时,可以忽略开挖长度对隧道的影响;分仓开挖步距越小,管廊开挖完成后隧道变形越小;存在最优注浆层厚度和灌注桩嵌固深度,超过最优值时,隧道变形基本不受影响。

In order to study the influence of long-distance and small-spacing pipe gallery excavation on the deformation of shield tunnels,relying on the common construction project of Shenzhen Metro Line 12 pipe gallery,numerical simulation software was used to simulate the comprehensive pipe gallery excavation to study the influence of different excavation length of pipe gallery on shield tunnel under the working condition of excavation width of 10. 5 m and the excavation depth of 6.5 m. The influence of different excavation steps,embedded depth of bored piles and thickness of grouting layer on tunnel deformation were studied to provide technical guidance for the subsequent construction of the integrated pipe gallery. The results showed that: the deformation of the tunnel below the excavation of the comprehensive pipe gallery increased with the increase of the excavation length,when the excavation length was 3 times greater than the excavation width,the influence of the excavation length on the tunnel could be ignored;the smaller the step of the bunker excavation was,the smaller the tunnel deformation after the completion of the excavation of the pipe gallery;there was an optimal thickness of the grouting layer and grouting pile embedment depth,beyond the optimal value,the tunnel deformation was basically unaffected by it.