砂-黏复合地层盾构地表沉降分析及沉降槽宽度系数修正

Study on Ground Surface Settlement Induced by Shield Construction and Modification of Width Parameter of Settlement Trough in Sandy-clay Mixed Stratum

以深圳地铁11号线宝安站—碧海站区间为工程背景,选择具有正态分布性质且能考虑沉降槽偏移的高斯峰值函数,对该段地表实测沉降数据进行曲线拟合,分析砂-黏复合地层条件下盾构掘进引起的地表沉降规律;并结合国内外沉降槽宽度系数的计算理论,提出砂-黏复合地层沉降槽宽度系数。结果表明:高斯峰值函数拟合的沉降槽曲线与砂-黏复合地层条件下的工程实际更为契合;通过选取合适的参数,可以运用日本学者竹山·乔公式对砂-黏复合地层地表最大沉降值进行预测,砂-黏复合地层地表最大沉降值随土的弹性模量的加权平均值的增大而减小;提出的砂-黏复合地层沉降槽宽度系数更能反映砂-黏复合地层特征,使沉降计算值更准确。

With reference to Shenzhen metro line 11, the Gaussian peak function with normal distribution and the capability to consider the migration of settlement trough is chosen to fit the surface settlement data of this segment and the law of ground settlement induced by shield tunneling is analyzed. Based on the calculation theories of the width coefficient of the settling trough at home and abroad, the width parameter of settlement trough in sandy-clay mixed stratum is proposed. The results show that： using Gauss peak function to fit the measured data is more suitable for engineering practice in sandy-clay mixed stratum; the formula provided by Japanese scholar Takemaya Kakashi can be used to predict the maximum ground surface settlement in sandy-clay mixed stratum once appropriate parameters are selected; the maximum ground settlement in sandy-clay mixed stratum decreases with the increase of the average value of the elastic modulus of the soil; the proposed width parameter of settlement trough can better reflect the characteristics of sand-clay mixed stratum,which makes the settlement calculation more accurate.