Mechanical behaviour of natural silts for geotechnical earthquake engineering practice

在过去的地震中，土壤的液化对建筑物和生命线造成了严重破坏，反过来又造成了生命损失和公民生活和工作条件的中断。加拿大不列颠哥伦比亚省（BC）的大温哥华地区位于地震高发地带，据估计，温哥华一场大地震造成的损失可能超过300亿美元，其中大部分与土壤液化有关。由于液化主要发生在松散的饱和砂土中，因此迄今为止的大部分研究都集中在砂土的液化上。最近的地震经验表明，天然淤泥的液化也是一个问题；众所周知，淤泥致密化以减轻液化比砂所需的方法更昂贵。

Liquefaction of soil has caused severe damage to buildings and lifelines during past earthquakes, and in turn, has led to loss of life and disruptions to living and working conditions of citizens. The Greater Vancouver Region of British Columbia (BC), Canada, is located in a zone of high seismicity, and it has been estimated that damage costs from a major earthquake in Vancouver could be over $30B with much of it associated with soil liquefaction. Much of the research focus so far has been on the liquefaction of sands since liquefaction has been observed predominantly in loose saturated sands. Recent earthquake experience suggests that liquefaction of natural silts is also a concern; it is also known that densification of silt to mitigate liquefaction is more expensive than the methods required for sands. Currently, there is no robust method to assess the liquefaction potential of natural silts primarily due to the lack of knowledge on silt behaviour. Hence, it is required to advance the fundamental knowledge on the mechanics of natural silts under seismic shaking; databases on silt response developed through systematic laboratory research are critical in this regard. Using Discovery Grant funds over the past six years, the applicant's research has led to initial findings on the silt behaviour and input for development of design guidelines. In the next five years, comprehensive experimental work on this subject involving four main research themes is proposed using the state-of-the-art facilities at the University of BC. The objective is to investigate the effects of the dominant physical factors on the liquefaction mechanisms of silts and develop engineering practice methods to assess liquefaction potential of silts using in situ testing. Three MASc and four PhD students will be trained during this work, thus adding to the earthquake geotechnical engineering expertise in Canada. The research findings will bridge the knowledge gaps on the behaviour of natural silts, and develop novel design methods with particular applicability to seismic design in civil and mining engineering fields.