Slope Stability Monitoring for Austrian Railway Compacted Soil Slopes
Release time: 2017-07-27
Traditional sensors provide only a limited number of soil slope readings.却能够采集边坡表面与内部的应变数据，得到边坡稳定性前所未有的综合剖面。The distributed optical fiber test systemcan collect the strain data on the surface and inside of the slope, and obtain a comprehensive profile of slope stability that has never been achieved before.
分布式光纤测试系统，为Semmering – Basistunnel项目的一段压实土边坡进行了全面的监测工作。In cooperation with the Austrian Railway (ÖBB), the Institute of Engineering Measurement and Measurement Systems of the Graz University of Technology hascarried out comprehensive monitoring of a section of compacted soil slope for the Semmering – Basistunnel projectusing adistributed optical fiber test system.
The 27.3-kilometer Semmering-Basistunnel is a very important project designed to provide high-speed rail connections to Austrian cities: Vienna, Graz and Klagenfurt.It is also a key component of the EU's Baltic-Adriatic High-Speed Railway Corridor initiative.
During the tunnel preparation process, a trench was dug to allow access to the construction site.Excavation of this trench, and subsequent tunneling work, produced a total of approximately 4.25 million cubic meters of earth and stone materials.These materials were placed in nearby, challenging mountainous terrain and existed in the form of reinforced soil structures: reinforced with soil nails and provided with geogrids.The completed structure is 1,300 meters in length and 25 meters in height.
分布式光纤测试系统和温度监测系统被用来提供全面的结构健康监测，不仅在施工阶段，竣工后也持续提供监测服务。In order to comprehensively monitor the stability of the reinforced soil structure, thedistributed optical fiber testing systemand temperature monitoring system are used to provide comprehensive structural health monitoring, not only during the construction phase, but also continuously providing monitoring services after completion.
Fiber optics are integrated into each layer of geogrid inside the geostructure.And use anchor bolts to ensure that the optical fiber and the geogrid maintain a good combination.
For each layer of fiber optic loop, half of the loop is pre-strained to ensure that any deformation of the geogrid can be sensed by the fiber.The other half of the loop remains slack, so relevant data can be collected for temperature compensation.
The total length of the fiber installed in the soil slope is 2 km.The fiber used is BRUStrain V4, produced by BruggKabel AG.
Tests and results
监测了土坡施工过程以及完工后长期的光纤应变变化。The distributed optical fiber testing systemmonitors the soil slope construction process and long-term fiber strain changes after completion.
The results show that with the construction of the slope, the strain sensed by the optical fiber continues to increase, and the largest change occurs early in the placement of earth and rock materials.
Effectively applying the calculation results to the engineering finite element analysis calculations helps engineers to have a more realistic understanding of the slope.
分布式光纤测试系统可以可靠地用于施工期边坡监测以及建成后的长期边坡监测。The project successfully proved that thedistributed optical fiber test systemcan be reliably used for slope monitoring during construction and long-term slope monitoring after completion.Strain sensing data provides a practical understanding of the soil structure from the inside.
In addition, the project also provides strong proof that fixing optical fibers to a geogrid is a reliable and feasible effective method for installing optical fibers into soil structures.