摘要
新建双线隧道先后施工会导致上部既有隧道产生差异沉降,容易引起结构变形与破坏。对不同覆跨比(H/D)、间径比(L/D)进行了数值模拟,得到了双线隧道开挖引起的地表沉降曲线与覆跨比、间径比的关系,并拟合了最大沉降与覆跨比、间径比的关系。由两者的拟合公式进一步得出地表沉降的修正系数K,并运用到二阶段法中,第一阶段将修正系数带入叠加的Loganathan公式中,得到修正的地表沉降,第二阶段将既有隧道视为Pasternak地基上的无限长梁,得出了既有隧道竖向位移的计算公式。结果如下:将修正后计算得到的地表沉降值代入Pasternak模型,并将计算结果和工程实测数据进行对比,修正计算得到的既有隧道位移曲线更符合工程实际情况,可反映新建双线隧道先、后施工对既有隧道的影响区别;随着间径比和覆跨比的增大,地表最大沉降对其敏感性逐渐降低,且对覆跨比更敏感;间径比和覆跨比的变化会引起修正系数K变化而导致双峰曲线产生差异沉降,两者增大都会使修正系数K减小,当修正系数K减小时,既有隧道的差异沉降也会相应减小,表示新建双线隧道先行线对后行线施工的影响逐渐减小,可以为今后同类工程施工设计提供参考。
The sequential construction of new double-track tunnels can cause differential settlement in the existing upper tunnel,potentially leading to structural deformation and damage.Numerical simulations were conducted for various ratios of cover-to-span(H/D)and ratios of spacing-to-diameter(L/D).The relationship between surface settlement curves and the ratio of cover-to-span and the ratio of spacing-to-diameter was established,and the relationship between maximum settlement values and the ratio of cover-to-span and the ratio of spacing-to-diameter was fitted,yielding good correlations.Furthermore,a modified surface settlement coefficient,K,was derived from the fitting equations and applied in a two-stage method.In the first stage,K was incorporated into the superimposed Loganathan formula to obtain corrected surface settlement values.In the second stage,the existing tunnel was modeled as an infinitely long beam on a Pasternak foundation,resulting in a formula for calculating its vertical displacement.The main conclusions are as follows:When the corrected surface settlement values are introduced into the Pasternak model and compared with field measurements and other methods,the resulting displacement curve of the existing tunnel shows better agreement with actual conditions,accurately reflecting the differential effects of sequential tunnel construction.As the ratio of spacing-to-diameter and the ratio of cover-to-span increase,the sensitivity of maximum surface settlement to these ratios gradually decreases.Moreover,maximum surface settlement is more sensitive to the ratio of cover-to-span than to the ratio of spacing-to-diameter.Changes in the ratio of spacing-to-diameter and the ratio of cover-to-span affect the modification coefficient K,thereby influencing the differential settlement pattern,including the development of a bimodal curve.An increase in both ratios results in a reduction of the modified coefficient K.As K decreases,the differential settlement of the existing tunnel also decreases,indicating that the influence of the leading tunnel on the subsequent tunnel construction becomes less significant.These findings offer valuable guidance for the construction design of similar projects in future.
作者
唐锐
晏莉
万晨锋
TANG Rui;YAN Li;WAN Chenfeng(School of Civil and Environmental Engineering,Changsha University of Science and Technology,Changsha,410114,China)
出处
《河南科学》
2025年第5期653-663,共11页
Henan Science
基金
国家自然科学基金项目(51408067)
湖南省教育厅优秀青年项目(18B136)
长沙理工大学“实践创新与创业能力提升计划”项目(CLSJCX23043)。
关键词
双线隧道
地表沉降
既有隧道
竖向沉降
double-track tunnel
land surface settlement
existing tunnel
vertical settlement
