Long-term performance of geotechnical transport infrastructure

现场监测为岩土运输基础设施（如路基、隧道和保留或破损的路堑）的真实的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，通常在相对较短的时间内进行，例如在施工期间或与特定的维护或补救要求有关。Robert Mair教授在2006年3月的Rankine讲座中展示了长期实地测量的价值，这可能表明基础设施的行为和条件以及周围地面的状态发生了意想不到的和不可预见的持续变化。由于本港运输基建的拥有人和保管人，有时会进行大规模的维修和翻新工程，以延长其经济寿命，因此，了解影响其长期运作和状况的因素，便变得越来越重要。近年来，南安普顿大学的地质力学研究小组已经在许多研究项目中安装了可记录的仪器，以调查性能在建造土木工程构筑物（例如运输基建的斜坡及护土墙）期间及其后的一段短时间内，在某些情况下，这种仪器仍然在原地工作，提供了一个独特的机会，继续监测，以了解结构的长期性能，因为平衡条件逐渐达到，也许是为了应对新的或不可预见的边界条件，如不断变化的气候模式和地下水条件或附近的进一步建设。拟议的研究提供了一个机会，以回答有关岩土交通基础设施的长期性能的一些问题，这些问题的答案几十年来一直难以捉摸。这些都是潜在的重新建立在原地侧向应力的保留结构在超固结沉积物;地下混凝土结构的应变计读数的解释，作为具体的年龄;周期性的季节变化对未加固和补救的切割和路堤边坡的稳定性的影响;和埋地结构和地下水之间的相互作用制度。所有这些都将在设计新的基础设施和预测使用寿命以及气候变化对现有结构的影响方面产生重大效益。

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.