Model Test Study on Deformation of Snowflake Shaped Steel Sheet Pile Based on OFDR

As a newly developed pile foundation, the snowflake shaped steel sheet pile is composed of three Y-shaped sections with an included angle of 120° and has a large specific surface area, which can give full play to the side friction of pile and improve the bearing capacity of single pile. At the same time, the snowflake shaped steel sheet pile has a high strength, relatively few materials, and it has good prospects with engineering applications. In order to accurately grasp the mechanical characteristics of the snowflake shaped steel sheet pile, this paper carried out the model test of snowflake shaped steel sheet pile based on OFDR (optical frequency domain reflector) distributed optical fiber sensor technology. The results show that: (1) OFDR distributed optical fiber sensing technology can effectively monitor the strain of snowflake steel sheet pile; (2) under the vertical load, the strain of snowflake steel sheet pile decreases along the length of the pile; (3) the strain of the same section of snowflake steel sheet pile is different at different positions, the strain at the junction between web and web is basically the same as the junction between web and flange, and the strain of the pile shaft on the flange edge is larger.

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Application of Distributed Optical Fiber Sensor Technology Based on BOTDR in Similar Model Test of Backfill Mining

Procedia Earth and Planetary Science ◽

10.1016/j.proeps.2011.09.006 ◽

2011 ◽

Vol 2 ◽

pp. 34-39 ◽

Cited By ~ 10

Author(s):

Shiqing Nan ◽

Qian Gao

Keyword(s):

Optical Fiber ◽

Model Test ◽

Optical Fiber Sensor ◽

Fiber Sensor ◽

Sensor Technology ◽

Similar Model ◽

Backfill Mining ◽

Distributed Optical Fiber Sensor ◽

Distributed Optical Fiber

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Investigation of Deformation Pattern and Movement Law of the Huge-Thick Conglomerate Stratum by a Large-Scale 3D Model Test with Distributed Optical Fiber Sensor Monitoring

Sensors ◽

10.3390/s21175985 ◽

2021 ◽

Vol 21 (17) ◽

pp. 5985

Author(s):

Qiang Yuan ◽

Jing Chai ◽

Yuzhu Zhang ◽

Yongliang Liu ◽

Yiwei Ren

Keyword(s):

Numerical Simulation ◽

Optical Fiber ◽

Model Test ◽

Large Scale ◽

Optical Fiber Sensor ◽

Fiber Sensor ◽

Deformation Pattern ◽

Distributed Optical Fiber Sensor ◽

Thick Stratum ◽

Distributed Optical Fiber

Mining activities under the circumstances of huge-thick stratum occurrence commonly result in dynamic response of the working face. It is crucial to understand the rock failure and movement of the huge-thick stratum in order to prevent dynamic hazards. This paper introduces distributed optical fiber sensor (DOFS) monitoring into a large-scale model test to investigate the deformation pattern and movement law of the huge-thick conglomerate (HTC); the monitoring results are verified by numerical simulation. The results indicate that DOFS monitoring captures the spatiotemporal evolution of zoning development in the overburden deformation. The deformation field of HTC is illustrated, and there exists a strain basin that can be used to estimate the movement law of HTC. The average strain variability Ex, a new homogenization index for characterizing the overburden deformation, is proposed to describe the broken rules of the HTC. The numerical simulation proves the feasibility of the DOFS monitoring method and the correctness of the deformation pattern and movement law. This study provides efficient methods for DOFS monitoring utilization to investigate mining engineering problems and could be beneficial for unearthing the mechanisms of deep ground rock deformation.

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Measurement Improvement of Distributed Optical Fiber Sensor via Lorenz Local Single Peak Fitting Algorithm

Symmetry ◽

10.3390/sym13071166 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1166

Author(s):

Bin Liu ◽

Jianping He ◽

Shihai Zhang ◽

Yinping Zhang ◽

Jianan Yu ◽

...

Keyword(s):

Optical Fiber ◽

Frequency Shift ◽

Optical Fiber Sensor ◽

Gain Spectrum ◽

Fiber Sensor ◽

Peak Fitting ◽

Fitting Algorithm ◽

Distributed Optical Fiber Sensor ◽

Brillouin Gain ◽

Distributed Optical Fiber

Brillouin frequency shift (BFS) of distributed optical fiber sensor is extracted from the Brillouin gain spectrum (BGS), which is often characterized by Lorenz type. However, in the case of complex stress and optical fiber self damage, the BGS will deviate from Lorenz type and be asymmetric, which leads to the extraction error of BFS. In order to enhance the extraction accuracy of BFS, the Lorenz local single peak fitting algorithm was developed to fit the Brillouin gain spectrum curve, which can make the BSG symmetrical with respect to the Brillouin center frequency shift. One temperature test of a fiber-reinforced polymer (FRP) packaged sensor whose BSG curve is asymmetric was conducted to verify the idea. The results show that the local region curve of BSG processed by the developed algorithm has good symmetry, and the temperature measurement accuracy obtained by the developed algorithm is higher than that directly measured by demodulation equipment. Comparison with the reference temperature, the relative measurement error measured by the developed algorithm and BOTDA are within 4% and 8%, respectively.

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