CN102278947A

CN102278947A - Packaged FBG (Fiber Bragg Grating) sensor for strain and crack test of bituminous concrete road surface

Info

Publication number: CN102278947A
Application number: CN2011101117362A
Authority: CN
Inventors: 赵拓; 赵雪峰; 王永成; 陈俊东
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2011-04-29
Filing date: 2011-04-29
Publication date: 2011-12-14
Anticipated expiration: 2031-04-29
Also published as: CN102278947B

Abstract

The invention discloses a packaged FBG (Fiber Bragg Grating) sensor for strain and crack test of bituminous concrete road surface. The sensor comprises three spring FBGs, three pure FBGs, a prefabricated bituminous concrete packaging structure, six through grooves, a temperature sensing groove, a temperature sensor and an armored cable, wherein the three spring FBGs and the three pure FBGs are respectively embedded into the upper and lower layers of through grooves; then, one ends of the spring FBGs and one ends of the pure FBGs are fixedly connected with the bituminous concrete packaging structure by glue; the spring FBGs and the pure FBGs are applied with prestress, and then the other ends of the six groups of FBGs are fixedly connected; the temperature sensor is embedded into the temperature sensing region; and finally, the armored cable is connected with the six groups of educed FBGs and the temperature sensor. The sensor disclosed by the invention has the advantages of simple process, convenience for laying, high precision and large measuring range, can realize the monitoring of main stress direction and size of the bituminous concrete road surface, is suitable for inside change of the bituminous concrete rod surface in health monitoring of civil engineering structures and is also suitable for industrialization.

Description

The packaging FBG sensor that is used for bituminous concrete pavement strain, crackle test

Technical field

The present invention relates to a kind of packaging FBG sensor that is used for bituminous concrete pavement strain, crackle test, be exactly by strain sensing technology specifically, utilize the monitoring of two groups of strain rosettes realizations of the grating fibers composition that pure fiber grating reaches and Microspring is fixed bituminous concrete pavement principal direction of stress and size based on fiber grating (FBG).This sensor uses bituminous concrete that the grating fibers of inner difference in functionality is encapsulated, and realizes the protection to fiber grating.

Background technology

Only experienced the short more than ten years till now from the appearance of fiber grating, but because the series of advantages such as accurate durable of fiber grating makes it develop the focus point that becomes the human sciences field rapidly.Optical fiber has had influence on thousands upon thousands people's daily life in the utilization of the communications field, and fiber grating also shows it gradually and is widely used in the importance in monitoring field.

The imbedded fiber grating sensor is a kind of new strain sensor based on Fiber Bragg Grating technology, is widely used in the engineering monitoring field, has progressively replaced traditional foil gauge.But most of fiber-optic grating sensor applies to the stress state of xoncrete structures such as large bridge, dam, highway, tunnel, skyscraper is implemented monitoring, but seldom relates to for the monitoring of bituminous concrete pavement.Simultaneously, only fiber-optic grating sensor that is used to measure the bituminous concrete internal strain also exists following two kinds of problems:

(1) error that encapsulating material caused: because bare optical fibers and bare optical gratings is too very thin, very easily in the pavement construction process, damage when imbedding bituminous concrete pavement, therefore must encapsulate, be not subjected to extraneous infringement to protect it to fiber grating.Existing sensors adopts non-asphalt concrete materials such as compound substance, steel pipe, steel disc as encapsulating material more, because the elastic modulus and the bituminous concrete elastic modulus in the environment to be measured of this type of material are inconsistent, sensor can make the stress field and the strain field redistribution of its near zone, causes its strain result who records and actual value to exist than big-difference.

(2) restriction of measurement range of strain: because the tensile elongation restriction of fiber grating own, the existing fiber grating strain transducer can only be monitored the small strain in the asphalt concrete structure.But be subjected to the bigger asphalt concrete structure of extraneous load for road surface etc., innerly often produce very big strain, even crack, existing sensor can not satisfy monitoring requirements.

(3) restriction of monitoring deformation type: the existing fiber grating sensor can only be monitored the strain on a certain direction in the concrete, can't measure the size and the direction of principal strain in the concrete plane.

Summary of the invention

The invention provides a kind of can the strain of precise monitoring bituminous concrete pavement, the fiber-optic grating sensor of crackle.This sensor adopts the material bituminous concrete of the bituminous concrete pavement of monitoring own to encapsulate, utilize identical materials, overcome the influence of the different elastic modulus of different materials to monitoring result: sensor inner fiber grating adopts the triangle strain rosette to lay mode, in the diabolo strain rosette, the measurement of each strain can accurately monitor the principal direction of stress and the size of concrete plane.Grating is all worked under large-length in the sensor, and efficient working range increases, so can truly more objectively reflect material strain, overcomes accidentalia to monitoring the bigger influence that may cause; Sensor internal has been buried the spring grating strain floriation underground, has realized the effective monitoring to big strain, big crackle and even big crackle; The use in conjunction of the pure grating strain floriation of sensor internal, spring grating strain floriation, temperature sensing grating, both realized the complementary work of height precision, big small strain is effectively monitored, realized temperature compensation again, temperature is to the influence of measurement result when having solved measurement.

Technical scheme of the present invention is as follows:

This packaging FBG sensor that is used for the test of bituminous concrete pavement strain, crackle comprises three spring fiber gratings, three pure fiber gratings, prefabricated bituminous concrete encapsulating structure, six through slots, temperature-sensitive groove, temperature sensor and armouring optical cables.Prefabricated bituminous concrete mould has six through slots and a temperature-sensitive groove, and six through slots are divided into upper and lower two layers, each three of the upper and lower; Three spring fiber gratings that are in tensile state place three through slots on upper strata, form the spring grating strain floriation; Three pure fiber gratings place three through slots of lower floor, form pure grating strain floriation; Residing through slot two ends are fixed respectively with separately for the two ends of spring fiber grating, the two ends of pure fiber grating; Temperature sensor places the temperature-sensitive groove, and spring fiber grating, pure fiber grating and temperature sensor connect with the armouring optical cable draws.

The invention has the beneficial effects as follows that technology is simple, be suitable for industrialization production, with low cost; Can monitor the principal direction of stress and the size on bituminous concrete plane for a long time; The encapsulating material that sensor adopted is a bituminous concrete, the measuring accuracy height.

Description of drawings

Fig. 1 is prefabricated bituminous concrete encapsulating structure synoptic diagram.

Fig. 2 is the packaging FBG sensor construction synoptic diagram that is used for bituminous concrete pavement strain, crackle test.

Fig. 3 is packaging FBG sensors A of the present invention-A sectional view.

Fig. 4 is a packaging FBG sensor B-B sectional view of the present invention.

Among the figure: 1 spring fiber grating; 2 pure fiber gratings; 3 temperature sensors; 4 armouring optical cables; 5 prefabricated bituminous concrete encapsulating structures; 6 through slots; 7 temperature-sensitive grooves.

Embodiment

Be described in detail specific embodiments of the invention below in conjunction with technical scheme and accompanying drawing.

The fiber Bragg grating strain sensor structure, structure as shown in Figure 1, Figure 2, Figure 3 and Figure 4, this strain sensing comprises three spring fiber gratings 1, three pure fiber gratings 2, prefabricated bituminous concrete encapsulating structure 5, two through slots 6, temperature-sensitive groove 7, temperature sensor 3 and armouring optical cables 4.At first respectively three spring fiber gratings, three pure fiber gratings are imbedded up and down in the two-layer through slot, with glue that one end and the bituminous concrete encapsulating structure of living in of spring fiber grating, pure fiber grating is fixed afterwards, the back applies prestress to spring fiber grating, pure fiber grating, the other end of fixed again six groups of fiber gratings, then temperature sensor is imbedded in the temperature zone, connected six groups of fiber gratings and the temperature sensor draw with the armouring optical cable at last.

Claims

1. packaging FBG sensor that is used for the test of bituminous concrete pavement strain, crackle, it is characterized in that this application bituminous concrete packaging FBG strain transducer comprises spring fiber grating (1), three pure fiber gratings (2), three prefabricated pitch bituminous concrete encapsulating structures (5), six through slots (6), temperature-sensitive groove (7), temperature sensor (3), armouring optical cable (4); Prefabricated bituminous concrete encapsulating structure has six through slots and a temperature-sensitive groove, and six through slots are divided into upper and lower two layers, each three of the upper and lower; Three spring fiber gratings that are in tensile state place three through slots on upper strata, form the spring grating strain floriation; Three pure fiber gratings place three through slots of lower floor, form pure grating strain floriation; Residing through slot two ends are fixed respectively with separately for the two ends of spring fiber grating, the two ends of pure fiber grating; Temperature sensor places the temperature-sensitive groove, and spring fiber grating, pure fiber grating and temperature sensor connect with the armouring optical cable draws.