High earth-rockfill dam deformation monitoring fiber sensing technology and system

Abstract

The invnetion discloses a distributed fiber sensing system and technical scheme and provides a high earth-rockfill dam deformation monitoring fiber sensing technology and system. Integrated online remote measurement of three components of internal deformation of all particulate dam material areas (including upstream rockfills of a core-wall dam) of a core-wall earth-rockfill dam and a concrete-faced dam, panel dam perimeter joint-vertical joint deformation, panel flexibility-disengagement joints and concrete-faced bidirectional strain can be realized; large-scope time-space full coverage is realized; three uniquely molded fiber packaging structures are provided, a three-dimensional Euler elastic beam is formed, and force-light direct conversion of fibers is realized; three arrangement modes of the sensing system in a horizontal direction, a vertical direction and a dam slope direction, an integrated application method and a fiber laying technology are brought forward, integration of multiple functions of fiber monitoring is realized, construction is facilitated, the fiber survival rate is guaranteed, and an engineering application value is demonstrated. An optical demodulation instrument employs a high-precision PPP-BOTDA or Brillouin-Rayleigh synthesis system, can realize multiple purposes through one machine with other monitoring projects including seepage and the like and facilitates updating and upgrading of a safety monitoring system.

Description

technical field [0001] The invention relates to a distributed optical fiber sensor monitoring system and technical scheme for the deformation of the dam body of an earth-rock dam, which can realize the distributed distribution of the internal deformation of the core wall type and the panel type high earth-rock dam, the two-way strain state of the concrete face and the joint deformation Optical fiber sensing large-scale-multi-dimensional online telemetry to obtain reliable and usable observation results. Background technique [0002] The observation frequency of the construction period-initial storage period-operating period stipulated in the national code SL60-94 for safety monitoring of earth-rock dams, internal deformation, concrete panel deformation-strain, and joint deformation are the highest among more than 20 monitoring items. This shows its crucial significance. Among them, the rigidity of the reinforced concrete and rockfill materials of the face dam is very differ...

AI Technical Summary

Problems solved by technology

[0003] Conventional instruments used for internal deformation monitoring of earth-rock dams, such as inclinometers, settlement meters, water pipe settlement meters, tension line displacement meters, indium wire displacement meters, strain gauges, joint gauges, etc., as single-point sensors, their space-time Weak coverage (discontinuity in time and space), few measuring points, and weak overall information on the dam; poor reliability and durability, high failure rate of equipment (for example, the effective working period of the electromagnetic sedimentation instrument is only about 5 years; another example is the Xiaolangdi Dam It has only been two years since the internal observation instruments were built, and more than 1 / 3 have failed; the 317m Nurek core wall rockfill dam in the former Soviet Union has more than 800 observation instruments and 16 inclinometer pipes buried in the dam body, with a total length of 3km. But so far there is no report on any observation results); conventional instruments have low level of automation, many manual operations, and poor timeliness

Another important problem is that conventional instruments and equipment are afraid of water immersion, and the deformation of the upstream dam shell rockfill body is usually a blank area for monitoring at home and abroad.

These problems become more and more challenging as the height of the dam increases, such as 2-300-meter-high dams

[0004] In 2005, the fiber optic gyroscope was used to monitor the panel deflection of the Shuibuya panel dam. The instrument has many moving parts (8 trolley rollers (rubber tires)), and the gyroscope trolley moves up and down in the circular steel pipe channel for each measurement. Dragging more than 800 meters (the trolley track lacks uniqueness), there are many adverse factors affecting the repeatability and stability of the measurement accuracy

[0010] To sum up, it is easy to see that the distributed optical fiber deformation monitoring method used in underground engineering can only measure the deflection of the package tube, that is, the one-dimensional deformation

Therefore, it cannot be applied to the internal deformation monitoring of the earth-rock dam type. There are two key problems: (1) The deformation of the earth-rock dam is spatial deformation, that is, three-dimensional deformation; (2) The smooth-encapsulated circular tube can only bear positive earth pressure and is easy to slide laterally , cannot be synchronized with the complex deformation of soil materials, and compatibility is the basic requirement of optical fiber sensing, that is, the optical fiber is compatible with the deformation field of the monitoring object

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