地铁盾构双线隧道地表横向变形特性与预测

Characteristics and Prediction of Surface Transverse Deformation of Double⁃line Shield Tunnel in Subway Tunnel

地铁盾构双线隧道地表变形因素影响众多,需深入分析其地表变形规律,有效开展变形预测研究。以北京地铁盾构双线隧道实测资料为基础,采用数值模拟方法研究了隧道中心埋深、隧道中心水平间距等对地表横向变形的影响。首次定义了双线隧道的相对间距系数,并建立了地表变形预测公式。研究结果表明:随着隧道中心间距的增加,双线隧道地表沉降槽逐渐由V形(或U形)转变为W形,双隧空间位置关系不同地表变形形态也不同;相对间距系数R_(1),R_(2)可用来描述双线地表变形形态变化;工程实测资料拟合得出地层损失率V_(l)和宽度参数k的统计结果,为地表变形预测参数的取值提供了参考;典型工程案例验证结果表明,地铁盾构双线隧道地表变形预测公式具有很好的适用性。

There are many factors affecting the surface deformation of double-line shield tunnel in subway tunnel,so it is necessary to deeply analyze its surface deformation law and effectively carry out deformation prediction research.Based on the measured data of double-line shield tunnel in subway tunnel in Beijing,the effects of tunnel central buried depth and horizontal spacing on ground transverse deformation are studied by numerical simulation method.The relative spacing coefficient of double-line tunnel is defined for the first time,and the prediction formula of surface deformation is established.The results show that:With the increase of tunnel center spacing,the surface settlement groove of double-line tunnel gradually changes from V-type(or U-type)to W-type.The spatial relationship of double-line tunnel is different,and the surface deformation form is also different;The relative spacing coefficients R_(1) and R_(2) can be used to describe the change of surface deformation form;The statistical results of formation loss rate V_(l) and width parameter k are obtained by fitting the engineering measured data,which provides a reference for the value of surface deformation prediction parameters;The verification results of typical engineering cases show that the surface deformation prediction formula of double-line shield tunnel in subway tunnel has good applicability.