为解决富水圆砾—泥岩复合地层采用双模盾构的适应性设计问题，依托南宁市轨道交通5号线五一立交站—新秀公园站隧道工程，针对穿越邕江、下穿浅基础建筑物、圆砾—泥岩复合地层中地表沉降和刀盘固结泥饼等施工风险，提出泥水/土压双模盾构结构和功能系统的针对性设计。在结构设计方面，双模盾构增设气垫仓稳定泥水压力，并配合排浆口优化设计实现了对地层沉降的稳定控制；加设中心面板和扭腿冲刷及“P0泵小循环”系统降低泥饼形成概率；优化的螺旋输送机设计减小喷涌压力，与邻近线路相比，过江段掘进速率提高近1倍。在功能性系统方面，实现泥水和土压2种排渣体系的快速转换；推进系统总推力达39 910 kN，满足不同掘进状态的需要；通过注浆系统与合理掘进参数实现对地表沉降的严格控制。
Adaptive design of dualmode
shield in waterrich gravelmudstone
composited strata is of great significance. As a result, the targeted designs
of structure and functional system of slurry/earth pressure dualmode shield used in Wuyi Interchange stationXinxiu Park station on Nanning Rail Transit Line No. 5 are put
forward according to the construction risks such as crossing through Yongjiang
River, crossing underneath buildings with shollow foundations, surface
settlement induced by shield boring in gravelmudstone
composited strata, and muck cake on cutterhead. As for structural design, the
air cushion chamber is used to stabilize slurry pressure, and the slurry
discharge port is optimized so as to realize the stable control of surface
settlement. The brush and P0 pump circulation systems are set on central panel
and bracket to effectively reduce the mud cake phenomenon. The design of screw
conveyor is optimized to reduce the gushing pressure, and compared with the
adjacent lines, the boring speed of the rivercrossing
section is increased by nearly one time. As for functional system, mucking
system conversion between slurry and earth pressure dualmode is realized, the total thrust of the propulsion system reaches
39 910 kN, which can meet relevant requirements under different working
conditions, the surface settlement is strictly controlled according to grouting
system and rational tunneling parameters control.
