双盾敞开式TBM适应性与工程应用对比分析

Comparative Analysis on Adaptability and Applications of Double-Shield Open Tunnel Boring Machines

为分析验证新型双盾敞开式TBM与传统主梁敞开式TBM的优缺点,以北江引水工程和那邦电站工程2个采用不同敞开式TBM机型的工程为例,首先,从主机结构、支护设备布置、施工优缺点等方面进行理论对比分析;然后,从掘进时间利用率、施工速度、地质适应性等方面进行工程应用效果对比。结果表明:1)双盾敞开式TBM在完整或较完整的Ⅱ类和Ⅲ类围岩条件下的施工速度与主梁敞开式TBM基本相当;2)在Ⅳ类和Ⅴ类围岩或断层破碎带条件下,双盾敞开式TBM的施工速度和适应性较差。建议完整或较完整围岩占比大、断层破碎围岩占比很小的小直径隧洞工程以及小转弯半径隧洞工程的施工,可选用新型双盾敞开式TBM。

To investigate the advantages and disadvantages of the new double-shield open tunnel boring machines(TBMs)and compare them with the conventional main-beam open TBMs,a case study is conducted on Beijiang water diversion project and Nabang hydropower station project bored by the two open TBMs.First,theoretical comparative analysis is conducted from the aspects of the main machine structure,rock support equipment layout,and construction advantages and disadvantages.Second,engineering application comparison is performed from the aspects of utilization rate of excavation time,construction speed,and geological adaptability.The results show the following:(1)Construction speed of both the TBMs is almost the same when tunneling in complete or relatively complete Grades Ⅱ and Ⅲ surrounding rocks.(2)For surrounding rocks of Grades Ⅳ and Ⅴ or fault fracture zones,the construction speed and adaptability of the double-shield TBMs are comparatively poor.Therefore,the double-shield open TBMs are recommended to be employed in small-diameter tunnels with complete or relatively complete surrounding rocks or less fault fracture zones and tunnels with small curvature radius.