Long-term performance of geotechnical transport infrastructure

现场监测为路堤、隧道和保留或破损的路基等岩土运输基础设施的真实行为提供了许多重要的见解，解决了研究、设计、施工控制或经济目的的不确定性。在进行这种监测的情况下，通常是在相对较短的时间内进行，例如在施工期间或与具体的维护或补救要求有关的时候。罗伯特·迈尔教授2006年3月的朗肯讲座展示了长期现场测量的价值，这可能表明基础设施和周围地面状态的行为和状况发生了意想不到和不可预见的持续变化。随着运输基础设施的拥有者和保管人试图通过有时大规模的日常维护和翻新来延长其经济寿命，对其长期行为和状态的因素的了解将变得越来越重要。近年来，南安普敦大学的岩土力学研究小组已在多项研究项目中安装了可记录的仪器，以调查交通基础设施的斜坡和挡土墙等岩土结构在建造期间和之后的短期表现。在某些情况下，这种仪器仍然存在并在工作，这为继续监测提供了一个独特的机会，以便在逐渐达到平衡条件时洞察结构的长期性能，可能是为了应对新的或不可预见的边界条件，如气候模式和地下水条件的变化或附近的进一步建设。拟议的研究提供了回答有关岩土交通基础设施长期性能的一些问题的机会，这些问题的答案几十年来一直难以捉摸。这些是在超固结矿床中的保持结构上重建原位侧向应力的可能性；地下混凝土结构中应变计读数随混凝土龄期的解释；周期性季节变化对未经加固和修复的路堤边坡稳定性的影响；以及埋藏结构与地下水状况之间的相互作用。所有这些都将在设计新的基础设施和预测气候变化对现有结构的使用寿命和影响方面带来重大好处。

Field monitoring has provided many important insights into the real behaviour of geotechnical transport infrastructure such as embankments, tunnels and retained or battered cuts, resolving uncertainties for research, design, construction control or economic purposes. Where such monitoring is carried out, it is usually over a relatively short period of time for example during construction or in connection with a specific maintenance or remediation requirement. Professor Robert Mair's March 2006 Rankine lecture demonstrated the value of longer term field measurements, which may indicate unexpected and unforeseen continuing changes in the behaviour and condition of the infrastructure and the state of the surrounding ground. As the owners and custodians of our transport infrastructure seek to extend its economical life through sometimes extensive in-service maintenance and refurbishment, an understanding of the factors governing its long-term behaviour and state will become increasingly important.In recent years, the Geomechanics Research Group at the University of Southampton has installed loggable instrumentation in connection with a number of research projects to investigate the performance during and for a short period after construction of geotechnical structures such as slopes and retaining walls for transport infrastructure. In some cases, this instrumentation is still in place and working, offering a unique opportunity to continue monitoring to gain an insight into the long-term performance of the structures as equilibrium conditions are gradually reached, perhaps in response to new or unforeseen boundary conditions such as changing climate patterns and groundwater conditions or further construction nearby. The proposed research offers the opportunity to answer some questions concerning the long-term performance of geotechnical transportation infrastructure whose answers have remained elusive for decades. These are the potential for the re-establishment of in situ lateral stresses on retaining structures in overconsolidated deposits; the interpretation of strain gauge readings in underground concrete structures as the concrete ages; the impact of cyclic seasonal variations on the stability of unreinforced and remediated cutting and embankment slopes; and the interactions between buried structures and the groundwater regime. All of these will have major benefits in terms of the design of new infrastructure and predicting the service life and impacts of climate change on existing structures.