昆明富水圆砾地层盾构渣土塑流性指标与合理改良方案研究

Research on Plastic-Fluidity Indices and Conditioning Method for Shield Muck in Water-Rich Gravel Stratum in Kunming, China

为避免在昆明地区广布的富水圆砾地层掘进时出现盾构掘进参数不稳定、渣土状态不良、螺旋输送机喷涌等风险,依托昆明地铁4号线盾构工程开展了一系列渣土塑流性测试与盾构掘进参数分析,提出了盾构推力、刀盘转矩、掘进速度、土舱压力的合理范围与渣土塑流性指标"坍落度"的求解方法,进一步采用规划求解的方法优化了针对该地区富水圆砾地层的渣土改良方案,明确了不同级配渣土含水率和泡沫注入比的合适范围。现场应用结果表明,依据左右线试验段监测数据提出的优化渣土改良方案有着良好的适用性,有效地改良了盾构渣土状态并将盾构各项掘进参数控制在合理范围内,为盾构的安全、高效掘进及后续近距离顺利下穿昆明地铁2号线提供了重要保障。

To avoid the risk of unstable tunneling parameters,poor muck state,and spewing of screw conveyor during shield tunneling in water-rich gravel stratum in Kunming,China,a series of tests and analysis are conducted on plastic-fluidity of muck and shield tunnel parameters of Kumming metro line 4,and reasonable ranges for shield thrust,cutterhead torque,tunneling speed,and soil chamber pressure and solution for plastic-fluidity index slump of muck are proposed.Further,the soil conditioning scheme of water-rick gravel stratum is improved using planning and solution method,and the rational water content and foam injection ratio for muck with different gradations are determined.The field application results indicate the good feasibility of improved soil conditioning scheme,providing guarantee for safe and efficient shield tunneling and follow-up shield crossing underneath Kunming metro line 2 with a short distance.