砂卵石地层盾构隧道地表最大沉降量预测

Prediction of the Maximum Surface Settlement of Shield Tunnel in Sandy Cobble Stratum

为了精准预算地表最大沉降量,对成都地铁17号线白机区间地表沉降监测数据进行回归分析得到沉降槽宽度i,分析了隧道埋深H与i的相关关系;提出了有效注浆率n2参数,修订了单位地层损失体积V的计算式;提出了用已知盾构刀盘半径、管片外径、总注浆率、出渣量、注浆量、渣土松散系数和隧道埋深等现场数据计算地表最大沉降量Smax的公式,并在成都地铁17号线机终区间进行了验算。研究表明:当隧道埋深H=10~19 m时,H与i的关系符合Allometricl模型;实例验算证明所提出的地表最大沉降量计算公式的计算结果更精确。

In order to accurately predict and calculate the maximum surface settlement,the regression analysis was carried out on the monitoring data of the white engine interval of Chengdu Metro Line 17 to obtain the width of settlement groove i,and the correlation between the buried depth of the tunnel H and i was analyzed.The concept of effective grouting rate n2 was put forward,and the calculation formula of loss volume per unit stratum V was revised.A formula for calculating the maximum surface settlement Smax was proposed based on the field data of known shield cutter-head radius,segment outer diameter,total grouting rate,slag discharge,grouting volume,slag soil loosening coefficient and tunnel buried depth,which was calculated and verified in the machine terminal section of Chengdu Metro Line 17.The research shows that when the tunnel depth H=10~19 m,the relationship between H and i conforms to the Allometricl model;the checking calculation by case study shows that the proposed calculation formula of the maximum settlement of the earth surface is more accurate.