盾构掘进中富含超大粒径漂石地层土体改良技术研究

Soil Conditioning Techniques for Shield Tunnelling in Strata with Large Size Boulders

对于盾构工法而言,富含超大粒径漂石地层是一种施工控制难度极大的地层,盾构在该地层中掘进时,由于土体塑流性差,土体在土舱内无法及时排出,时常出现盾构推力、刀盘扭矩异常增大,推进速度极其缓慢等现象。同时,由于土舱土体颗粒之间为点对点传力,支护压力不能有效地施加到开挖面,极易出现地表沉降超限、塌方等事故。通过土体改良改善土舱内土体的性状和流塑性,是提高盾构掘进效率和控制开挖面稳定性的重要措施。以北京地铁9号线06标"军事博物馆站—东钓鱼台站"区间盾构工程为背景,开展盾构掘进过程土体改良试验,找出适用于不同类型富含超大粒径漂石地层的盾构土体改良剂。

It is very difficult for EPB TBM to advance smooth- ly in strata with large size bonders due to poor flow plastic a- bility of the soil in earth chamber when EPB TBM excavates, the shield thrust and cutterhead torque will increase quickly a- gainst the delayed advance speed. At the same time, it is diffi- cult to apply the support earth pressure to the working face be- cause of the point to point force transmission mode between particles, thus causing the ground surface settlement transfinite and collapse accidents. Soil conditioning is a way to improve the advancing efficiency and control the stability of excavation face by adjusting the soil conditions and increasing the flow a- bility. Taking EPB TBM tunnelling engineering between Milli- tary Museum and East Diaoyutai Station on Beijing metro Line 9 as the background, soil conditioning tests are carried out in EPB TBM construction process, in order to find the reasonable soil conditioning agent for different kinds of strata with large size boulders.