成都地铁盾构4标段泥水与土压两种盾构机的适应性分析

Analysis on the Adaptability of Slurry Shield and Earth Pressure Balanced Shield to Lot 4 of Chengdu Metro

成都地铁盾构4标段是成都地铁一号线盾构施工试验段,为便于以后盾构机能更准确地选型,本试验段分别采用一台泥水盾构机与一台土压盾构机进行左右线的掘进。通过对两台掘进机的适应性分析可以看出:泥水盾构的缺点是容易堵塞、出碴效率低、对地层完整性要求高、在含泥地层中容易封住开口、对进出洞密封要求高、施工中需要较大场地、施工成本高;优点是对地层扰动小、便于带压进舱。土压平衡盾构的缺点是刀盘磨损严重、地表沉降控制难度高,带压进舱困难;优点是不受出碴限制、掘进速度快、便于维护、成本低。施工实践证明:在地表要求不太严格的情况下适于用土压平衡盾构;在地表要求高、场地较大情况下,适合用泥水盾构。

On the test section in Lot 4 of Chengdu metro,a slurry shield and an earth pressure balanced shield were adopted simultaneously to drive the left and right tunnels in order to determine which shield would be more adaptable.Defects of the slurry shield comprised the liability to be blocked in soil-content ground,low efficiency for mucking,high requirements for the integrity of ground,more space required and higher construction cost.Merits of it consisted in less disturbance to the ground and convenience for entering the cabin under pressure.Defects of earth pressure balanced shield included severe abrasion of cutters,difficulty in controlling surface subsidence and entering the cabin under pressure.Merits of it consisted in higher advance rate without the restriction of mucking,convenient maintenance and lower cost.Comparison indicated： earth pressure balanced shield is adaptable when the requirements for surface subsidence are not very strict;slurry shield is adaptable when the surface subsidence is strict and the working site is broad.