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针对上海软土地区盾构隧道工程,在盾构穿越监测断面全过程调整掘进速度,观察监测断面的水、土压力以及地层稳定性变化。根据实测并结合土体固结比、承压水等地层土性影响,运用土体扰动机制综合评定掘进速度改变的影响规律。分析表明,盾构在软土地区4倍直径(D=6.2 m)埋深地层中施工,在盾构土舱压力、注浆量等参数均不变的条件下,仅调整千斤顶推进速度变化对土体压力及变形的扰动效应有较大影响。盾构推进速度降低会使水、土压力的扰动空间范围减小、扰动所产生的压力增量减小,也使地表隆沉变化值更稳定。相应变化值由埋深和推速降低比例决定。试验为今后判断软土地区4D埋深盾构掘进速度扰动效应提供参考。
According to the shield tunneling project in Shanghai soft soil area, the tunneling speed is adjusted in the whole process of shield crossing monitoring section, and the changes of water and earth pressure and stratum stability are observed. According to the measured and combined soil consolidation ratio, confined water and other formations, the influence of the change of heading speed is evaluated synthetically by using soil disturbance mechanism. The analysis shows that the shield is constructed in 4 times diameter (D = 6.2 m) buried depth in the soft soil area. Under the condition of unchanged parameters such as pressure and grouting in the shield soil, only the jacking speed variation Soil pressure and deformation of the disturbance effect has a greater impact. Decreasing the speed of shield advancement will reduce the disturbance of water and earth pressure, reduce the pressure increment caused by disturbance, and make the change value of ground surface sediment more stable. The corresponding change in value is determined by the ratio of burial depth and thrust reduction. The experiment provides a reference for judging the velocity disturbance of 4D buried shield in soft soil area in the future.