运营期内河水位变化影响下的水下小净距隧道衬砌受力性状研究

To the traffic tunnels with small clear spacing crossing the river in the city by the shallow mining method, one of the most important problems to design and operation management is the long-term mechanics character of lining during the operation. The perennial change of the water level of the river not only alters the permeation ability of water into tunnel, but also produces the approximate ultra-low-frequency cyclic loading, which differs from the ocean tide and the traffic cyclic loading, the study on the long-term mechanics character of lining considering the effect from water level change of the river is far behind the demand of engineering practice. By the solid-fluid coupling model tests, the long-term mechanics character of lining of the tunnels with different clear spacing during the operation will be studied mainly considering the effect from water level change of the river; the indoor triaxial rheological test will be designed considering the effect of water level change of the river on rheological property of soft rock, the rheological model of surrounding rock will be established by the test and imbedded into ABAQUS by writing the subprogram, the long-term mechanics character of lining will be analyzed by the numerical simulation considering solid-fluid coupling and many working cases; by the field test, the change characteristic of water penetration and stress of secondary lining going with the water level change of the river will be analyzed. By the systematic analysis on the results obtained by different research ways, the long-term developing law and characteristic of lining internal force and deformation during the operation will be revealed considering the effect from water level change of the river, which can provide important reference suggestions for tunnel design and operation management.

对于浅埋暗挖法修建的穿越城市江河的小净距交通隧道，运营期内衬砌的受力性状是隧道设计和运营管理最为关注的内容之一。河水水位常年变化既改变水向隧道渗透的能力，又产生一种近似于超低频的循环荷载，与海洋潮汐、交通车辆循环荷载不同。河水水位变化影响下衬砌长期受力性状的研究远滞后于工程实践的需要。本项目突出河水水位变化这一主要影响因素，通过流固耦合模型试验，研究运营期内不同净距隧道的衬砌受力性状；考虑河水水位变化对隧道软岩流变力学性质的影响设计室内三轴流变试验，基于试验构建围岩的流变本构模型，编制相应的子程序嵌入到 ABAQUS软件中进行流固耦合仿真计算，分析多种工况下衬砌的长期受力性状；通过现场测试，分析二衬应力和隧道渗水随河水水位变化的特性。综合分析采用各种研究手段得到的结果，揭示在隧道运营期内河水水位变化影响下的衬砌内力变形发展规律和特征，为隧道设计和运营管理提供重要的参考意见。

随着我国城市化进程的加快，市区穿越江河的交通途径相对不足已日益成为制约城市发展的瓶颈。水下隧道作为穿越城市江河的一种交通方式，近些年来得到了迅速发展。对于浅埋暗挖法修建的穿越城市江河的小净距交通隧道，运营期内衬砌的受力性状是隧道设计和运营管理最为关注的内容之一。河水水位常年变化既改变水向隧道渗透的能力，又产生一种近似于超低频的循环荷载，与海洋潮汐、交通车辆循环荷载不同。河水水位变化影响下衬砌长期受力性状的研究远滞后于工程实践的需要。本项目基于现场观测与现场调查，分析了多年的河水位变化特性，分析了隧道的渗水情况与运营状况。考虑河水水位变化的影响，开展了不同二衬透水性能、不同净距的多种工况的模型试验，得出了隧道运营期内二衬应变、土压力、水压力等的变化特性。通过反复加卸载的室内流变试验，得到了河水位变化影响下围岩的蠕变特性。建立了考虑渗流应力耦合与河水位变化影响的数值计算模型，将室内试验得到的围岩流变本构模型嵌入到数值模型中进行计算，研究了多种工况下衬砌的长期受力特性。通过分析采用各种研究手段得到的结果，揭示了在隧道运营期内河水水位变化影响下的衬砌内力变形的发展特征，为隧道设计和运营管理提供了重要的参考意见，以保障隧道的长期安全性。