The development and application of a micro-geomechanical approach to investigate the long-term performance of subsurface structures

我们的许多地下隧道都有50多年的历史，加拿大每年投资数十亿美元用于交通、行人和下水道隧道的维修。这就需要了解不同隧道衬砌系统的长期失效机制。大多数研究都考虑了隧道在其使用寿命的初始配置，通过考虑隧道衬砌如何单独退化来确定使用寿命。实际破坏往往涉及土壤和衬砌条件的变化及其相互作用。地下结构（隧道、竖井和埋地管道）附近的土壤弱化力学是一个具有挑战性的土壤-结构相互作用问题，涉及颗粒运动和衬砌与支撑地面的分离。因此，需要进行研究，以解释考虑土壤和衬砌条件影响的不同部件之间的相互作用。 这个发现补助金申请的基本主题涉及微地质力学方法的开发和应用，以解决涉及大变形的复杂土壤-结构相互作用问题，重点如下：（i）开发一种有效的离散颗粒方法来分析大规模非线性岩土工程问题（ii）研究地下结构附近土壤弱化和颗粒运动的力学，并了解由于土壤弱化过程而导致的接触压力分布的渐进变化，（iii）研究局部土壤弱化对受损结构的静态和地震反应的不利影响;（iv）评估施工活动对隧道造成的损害。这些主题对岩土工程工作至关重要，对我们的生活质量产生影响，特别是因为这些地下结构被认为是提供对我们社区功能至关重要的关键服务的生命线。 上述研究计划将包括在五年资助期内培训三名硕士和六名博士生以及几名暑期学生。

Many of our underground tunnels are more than 50 years old, and Canada invests billions of dollars each year on transportation, pedestrian and sewer tunnel repair. This has established a need to understand the long term failure mechanism of different tunnel lining systems. Most research has considered tunnels in their initial configuration over their service life, setting that service life by considering how the tunnel lining alone degrades. Actual failure often involves changes in soil and lining conditions and their interaction. The mechanics of soil weakening in the vicinity of subsurface structures (tunnels, vertical shafts and buried pipes) is a challenging soil-structure interaction problem that involves particle movement and lining separation from the supporting ground. Research is, therefore, needed to explain the interaction of different components considering the effect of soil and lining conditions. The underlying theme of this Discovery Grant application relates to the development and application of a Micro-Geomechanical approach to solve complicated soil-structure interaction problems involving large deformations with emphasis on the following: (i) Developing an efficient discrete particle method to analyze large scale nonlinear geotechnical engineering problems (ii) Investigating the mechanics of soil weakening and particle movement in the vicinity of subsurface structures and understanding the progressive changes in contact pressure distributions due to the soil weakening process, (iii) Examining the adverse effects of local soil weakening on the static and seismic response of deteriorated structures, (iv) Evaluating the damage to tunnels caused by construction activities. These topics are critically important to geotechnical endeavours, which have an impact on the quality of our lives, particularly as these subsurface structures are considered lifelines that provide critical services vital to the function of our communities. The above research program will involve training three Master and six Doctoral students in addition to several summer students over the five year funding period.