Optical Fiber System for Measuring Pore Pressures during Progressive Failure

在过去的30年里，光纤传感技术的使用已经扩展到广泛的科学学科。该技术及其在专业仪器中的应用开始出现在20世纪80年代，随着为电信行业开发的实用光纤的出现。无源光纤器件和有源光电元件在传感器尺寸、性能、耐用性和成本降低方面的进步，使光纤传感器在各个行业的应用更加普及。在岩土工程领域，光纤正越来越多地用于实验室和现场应用，研究人员必须在较大的土壤质量，沿着裂缝或孔隙空间内的微观尺度上获得高质量的性能数据。 阿尔伯塔大学工程学院土木与环境系的一个经验丰富的研究小组建议将医疗行业使用的微光纤压力传感器技术整合到几项岩土工程研究中。这些传感器最初是为医疗应用而开发的，可以在冠状动脉的小部分内进行压降测量;高灵敏度的传感器产生的数据上级一致且准确，优于以前的可能性。我们团队要求的微光纤系统包括压力传感器、专门的数据采集系统和改进的剪切盒，以增强我们现有的伺服控制直接剪切设备。该系统将用于在剪切和多相流测试期间捕获土壤和岩石的内部孔隙压力测量值。应用这项技术来检查内部孔隙压力是一个独特的机会，以提高我们的理解耦合地质力学发生在土壤和岩石在岩土工程的广泛的学科，并将是第一次在加拿大的应用。 所要求的微光纤孔隙压力监测系统和改进的剪切盒将使我们的团队能够开发创新的方法来监测内部孔隙压力响应，并为岩土工程领域具有强大技能的学生和研究人员提供尖端的研究和培训机会。这些测量将有助于更好地理解土壤和岩石的耦合地质力学，从而使工程师能够优化各种封闭地下场地的操作（例如核废料储存库，从水库中提取碳氢化合物）。

Over the past 30 years, the use of fiber-optic sensing technology has spread across a broad range of scientific disciplines. The technology and its application within specialized instrumentation started to emerge in the 1980s with the advent of practical fiber-optics developed for the telecommunications industry. Advances in sensor size, performance, durability and reduced costs for passive optical fiber devices and active opto-electronic components has led to firmer penetration of fiber-optic sensor use in various industries. Within the geotechnical field, fiber optics are being increasingly used in laboratory and field applications where researchers must acquire high quality performance data within larger soil masses, along fractures or at the microscale within pore spaces. An experienced team of researchers in the Civil and Environmental Department in the Faculty of Engineering at the University of Alberta is proposing to integrate microfibre-optic pressure sensor technology used within the medical industry into several geotechnical studies. Having been originally developed for medical applications, these sensors allow for pressure drop measurements to be made within small sections of coronary arteries; the highly sensitive sensors produce consistent and accurate data superior to what was earlier possible. Our team's requested microfiber-optic system includes pressure sensors, a specialized data acquisition system and a modified shear box to enhance our existing servo-control direct shear device. This system will be utilized to capture internal pore pressure measurements of soil and rock during both shear and multiphase flow testing. Applying this technology to examine internal pore pressures is a unique opportunity to advance our understanding of coupled geomechanics occurring in soil and rock across a broad range of disciplines within geotechnical engineering and would be the first application of its kind in Canada. The requested microfiber-optic pore pressure monitoring system and modified shear box will enable our group to develop innovative approaches to monitor internal pore pressure responses and provide cutting edge research and training opportunities for students and researchers with strong skills in geotechnical engineering. These measurements will facilitate a greater understanding of the coupled geomechanics of soil and rock, which then allow engineers to optimize operations in a variety of confined underground sites (e.g. nuclear waste repositories, extraction of hydrocarbons from reservoirs).