稳定地层盾尾管片壁后注浆窜浆机理及模型试验

Escaping mechanism of shield tail grouting and its model test during shield tunnelling surrounding rock stratum

在稳定性地层中盾构掘进,盾尾管片壁后注浆将不可避免沿着盾壳与地层之间的缝隙窜浆到刀盘和开挖面。基于宾汉姆流体建立盾尾注浆窜浆量理论计算公式,并分析流失量与浆液性质、缝隙厚度、注浆压力差的关系。建立盾尾注浆窜浆试验模型,并开展不同性质的浆液、缝隙厚度和注浆压力差的窜浆模型试验,验证了本研究建立的窜浆量理论计算公式的合理性。基于建立的盾尾注浆窜浆量计算公式,得到地铁常用盾构盾尾壁后注浆窜浆的发生条件,即浆液黏滞阻力与盾壳与围岩地层缝隙厚度的关系,可用于指导稳定围岩地层盾构掘进时盾尾浆液的配制。

When shield machine goes through the stable rock stratum,the backfilled grouting behind the segmental linings will inevitably escape along the gap between the shield shell and the stratum to the cutter plate and the excavation surface.Based on Bingham fluid,the theoretical calculation formula of the loss amount for the shield tail grouting escaping was established,and the relationship between the loss amount of grouting,the properties of grouting,gap thickness and grouting pressure was analyzed.The experimental models with different properties of grouting,gap thickness and grouting pressure for escaping of shield tail grouting were established and tested,and their results verified the rationality of the theoretical calculation formula proposed.Based on the formula for calculating the amount of escaping grouting of shield tunnel,the critical condition of the escaping grouting commonly occurred in subway tunnel construction was obtained,i.e.the relationship between the viscosity resistance of grouting and the thickness of gap between the shield shell and surrounding stratum.The findings can be expected to guide the preparation of grouting of shield tunnelling in stable rock stratum.