敞口式盾构关键技术与应用

为解决常规密闭式土压盾构在砂卵石、大漂石等地层中施工经常遇到刀盘被困而无法正常掘进的难题,STM063D1地铁用敞口挖掘式盾构机,采取敞开式挖掘,土体支护装置采用"帽檐式盾体结构+可伸缩前檐+可收放正面挡板"3种不同组合支护方式,螺旋机采用常压出土等技术。通过相应的部件试验检测以及整机试掘进试验,得出敞口挖掘式盾构工法相比土压盾构在特定的范围内能适应土体自立性好、基本不含水或降水的砂卵石地层的特点。敞口式盾构及相应工法值得在北京地区及全国范围推广应用。

Key Technologies for and Application of Open Shield

Jamming always occurs to EPB shield when tunneling in strata with large diameter boulders. As a result, STM063D1 open shield is developed. Technologies, including open mode excavation, supporting mode of “hat brim type shield body + retractable shield front + removable front plate”, and screw conveyor working under atmospheric pressure, have been used for the mentioned shield. The open shield has been successfully used in Phrase Ⅱ project of No. 6 Line of Beijing Metro. The tests of key parts and the tunneling practice show that, compared to EPB shield, the open shield is more suitable for sandy cobble ground with good self support capability and containing almost no water. Open shield and related technologies are worth to be popularized in Beijing and other regions in China.