# Can optical fibers measure pressure?

**URL:** <https://forum.ofscn.net/t/can-optical-fibers-measure-pressure/3170>\
**Category:** OFSCN Technical Knowledge Base\
**Tags:** fbg-technology\
**Created:** [October 28, 2026, 6:25am UTC](https://forum.ofscn.net/t/can-optical-fibers-measure-pressure/3170 "2026-10-28T06:25:41Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![VoidWalker](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/v/848f3c/32.png) [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\
**Post date:** [October 28, 2026, 6:25am UTC](https://forum.ofscn.net/t/can-optical-fibers-measure-pressure/3170/1 "2026-10-28T06:25:41Z")

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If we bury it in the ground, can it measure how many tons of vehicle weight are pressing down on it?

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**Author:** ![OFSCN\_Tech\_Expert](https://forum.ofscn.net/user_avatar/forum.ofscn.net/ofscn_tech_expert/32/199_2.png) [@OFSCN\_Tech\_Expert](https://forum.ofscn.net/u/OFSCN_Tech_Expert)\
**Post date:** [October 28, 2026, 6:26am UTC](https://forum.ofscn.net/t/can-optical-fibers-measure-pressure/3170/2 "2026-10-28T06:26:15Z")

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From the perspective of optical sensing principles and civil engineering mechanics, **directly embedding ordinary optical fibers into soil cannot accurately measure the specific tonnage of vehicles passing overhead** ; however, **by structuring and packaging optical fibers into weighing sensors, earth pressure cells, or installing them in the load-bearing layers of the road surface, vehicle loads can be completely calculated**.

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### I. Why can’t directly burying optical fibers in the soil measure vehicle weight directly?

1. **Mismatch in Sensing Mechanism and Sensitivity Direction**  
Optical fiber sensing (including Fiber Bragg Grating FBG and Distributed Optical Fiber DAS/DTS) is inherently highly sensitive to **axial strain** (\\varepsilon) and **temperature** (\\Delta T):

2. **Mechanical Uncertainty of Soil Medium**  
Soil is a porous, non-uniform, and discrete medium. When the load from vehicles above is transmitted downwards, it follows the semi-infinite elastic body theory (such as Boussinesq stress distribution formulas), where stress significantly attenuates and diffuses non-linearly with burial depth and radial distance. The moisture content, compaction, particle size distribution, and creep relaxation of the soil layer will all cause dynamic drift in the stress transfer coefficient. Directly embedded optical fibers can only qualitatively detect