Construction Sequence Optimization and Settlement Control Countermeasures of Metro Tunnels Underpassing Expressway

<table class="table-group" id="tab4"><tr><td><table class="table"><tr><td class="thead-hr" colspan="7"><hr/></td></tr><tr class="thead"><td class="align_left">Small pipes</td><td class="align_center">Length (mm)</td><td class="align_center">Longitudinal spacing (mm)</td><td class="align_center">Circumferential spacing (mm)</td><td class="align_center">Extrapolation angle (°)</td><td class="align_center">Grouting hole</td><td class="align_center">Notes</td></tr><tr><td class="thead-hr" colspan="7"><hr/></td></tr><tr><td class="align_left">Inner layer</td><td class="align_center">5</td><td class="align_center">2.5</td><td class="align_center">0.4</td><td class="align_center">40</td><td class="align_center" rowspan="2">Plum blossom arrangement with 0.5 m spacing</td><td class="align_center" rowspan="2">Chemical grouting</td></tr><tr><td class="align_left">Outer layer</td><td class="align_center">3.5</td><td class="align_center">2.0</td><td class="align_center">0.3</td><td class="align_center">10∼15</td></tr><tr class="table-tr"><td colspan="7"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>Parameters of the advanced small pipes.</div>

Advances in Civil Engineering

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Table 4

Table 4: Construction Sequence Optimization and Settlement Control Countermeasures of Metro Tunnels Underpassing Expressway 