本文系统综述5大类地铁施工诱发地表最大沉降量S_(max)的预测公式及其适用性,并以大量的国内地铁实测沉降资料为依据,总结地铁在不同覆跨比H/D、不同地层条件和不同施工方法下的S_(max)、沉降槽宽系数k、地层损失率V_l及间隙参数g的变化规律及其经验关系。结果表明:(1)经验法需要归纳大量监测成果来预测S_(max);解析方法多适用于地层条件相对单一的施工期不排水条件下沉降估算;半经验公式存在较大的地区性差异;(2)S_(max)主要与地铁所处的一般性地层条件(为了保护临近重要建(构)筑物而采取辅助施工措施来超前加固地层的特殊情况除外)、覆跨比H/D、施工方法等因素有关,其中S_(max)与H/D呈反相关,不同地层条件下盾构法(土压、泥水)施工所诱发的S_(max)平均值为-11.5~-31.3 mm,浅埋暗挖法下S_(max)离散性较大,其平均为-13.0~-41.6 mm,表明在控制地表沉降方面盾构法较优于浅埋暗挖法;(3)不同地层和H/D条件下S_(max)=(-0.28~-0.71)g,S_(max)/g和H/D关系可采用修正Atkinson公式(α=0.15~0.28)及Clough公式(β=-0.55~-1.11)来描述。通过本文系统的总结分析,可相对全面地了解城市地铁施工诱发S_(max)的预测方法及其各自的适用性,为后期类似地铁工程施工诱发地表沉降的准确预测提供科学参考。
5 methods and their applicability for estimating the maximal surface settlement(Smax) induced by subway construction were summarized. Based on the large numbers of surface settlement measurements, the variation regularities of Smaxx, the coefficient of settlement tough width(k), volume loss(E), the gap parameter(g) were obtained. The results show that: (1) the empirical method can be widely and well used on the basis of measurements, the analytical method is only apply to the homogeneous soil and undrained conditions, there are the regional differences with semi-empirical method. (2) Besides the special soil conditions with preceding reinforcing methods, the general soil conditions, H/D and construction technologies are the major influence factors on the Smax- Smax is inversely correlated with H/D, the average value of Smax is between - 11.5 mm and -31.3 mm with shield tunneling method, however, the average value of SmaxiS from -13.0 mm to -41.6 mm for the shallow tunneling method, it indicates that the former method is superior to the latter. (3) The relation between Smax and g can be expressed as Smax= (-0.28 to-0.71)g, and Smax/g versus H/D can be described with modified Atkinson formula( α= 0.15- 0.28)and Clough formula( β =-0.55- 1.11). Through the systematic summarization, the estimation methods and their applicability of Smax can be completely understood and provide a scientific reference for the similar subway projects.