无锡软土地层盾构施工下Peck公式的修正

在地铁隧道施工过程中,引起地表沉降的因素较多,致使一些常用的地表沉降评价预计方法出现较大的偏差。为了研究由于地铁隧道施工而引起的地表沉降问题,以无锡地区地铁隧道开挖过程中大量地表沉降实测数据为基础,采用数学方法,引入两个修正系数,即地表最大沉降修正系数α和沉降槽宽度修正系数β,修正Peck公式中两个重要参数(沉降槽宽度系数K、地层土体损失率η),以适应无锡软土地区研究区段的工况。研究表明:地表最大沉降修正系数α介于0.5~0.9,沉降槽宽度修正系数β介于0.5~0.9,此时沉降槽宽度系数K介于0.40~0.70,底层土体损失率η介于0.4%~0.9%,得到修正后的Peck曲线与地表实测沉降数据更吻合。

Modification of Peck Formula under Soft Soil Layer Shield Method Construction in Wuxi

In the metro tunnel construction process, there are many factors that cause the ground surface settlement, resulting in larger large deviation in some of the commonly used ground settlement prediction and evaluation methods. In order to study the ground settlement caused by the metro tunnel construction, this paper has presented two correction coefficients—the maximum ground settlement correction coefficient α and the settlement groove width correction coefficient β by mathematical method, based on a large number of ground surface settlement data measured in the process of the metro tunnel excavation in Wu xi to amend two important parameters(the settlement groove width coefficient K and the stratum soil loss ratio η)in the Peck formula for the purpose of adapting the working condition of the study section in the soft soil area in Wu xi. The research result shows that if the maximum ground settlement correction coefficient is between 0.5 and 0.9, and the settlement groove width correction coefficient is between 0.5 and 0.9, the settlement groove width coefficient K is between 0.4 and 0.7 and the stratum soil loss ratio is between 0.4 % and 0.9 %, the modified Peck curve is more consistent with the ground settlement data.