地铁隧道施工地表沉降槽宽度系数取值研究

Research on the Calculation of the Settlement Width Through Influenced by Shield Tunneling

Peck公式广泛用于地铁隧道施工地表沉降计算,沉降槽宽度系数（i）是该公式的主要参数之一。目前各类沉降槽宽度系数（i）计算式多为现场实测数据或室内试验数据拟合求出,不能理论地反映出沉降槽宽度系数（i）与隧道埋深、地层土的性质、隧道半径的关系。从地表沉降曲线变形规律出发,假定地层在沉降曲线拐点处稳定状态发生变化,提出土体破坏剪切面通过沉降曲线的拐点的观点,基于太沙基极限平衡原理,求出了地表沉降槽宽度系数（i）计算式。两组工程实例的实测数据与计算沉降曲线的对比表明实测数据与预测结果吻合良好,误差较小,验证了提出的沉降槽宽度系数（i）计算式的准确性和适用性。

It＇s well known that width parameters（i）of settlement trough is the key parameter of Peck formula which is widely used to calculate the ground settlement caused by shield tunneling.At present,the calculation formula of various types of width parameters of settlement trough are mostly fitted with measured data or experimental data,which cannot reflect the relationship between the value of width parameters of settlement trough and the buried depth of tunnel,the nature of formation soil and the radius of tunnel in theory.In this paper,according to the deformation rule of settlement curve calculated by Peck formula,it is considered that the stress state changes at the inflection point of the settlement curve,and based on the Terzaghi limit equilibrium principle,the view of soil shear failure surface settlement curve is put forward through the inflection point,on this basis the calculation formula of width parameters of settlement trough is obtained.Through the comparison with the existing calculation formula of various types of width parameters of settlement trough,the rationality and universal applicability of the calculation formula of width parameters of settlement are analyzed through proposed.Finally,the accuracy and applicability of the proposed calculation formula of width parameters of settlement trough are verified by two sets of engineering examples.