阅读说明：本技术 一种观测井内地下水流向流速监测的光纤探测装置 (Optical fiber detection device for monitoring flow direction and flow velocity of underground water in observation well ) 是由 茅昌平 宋政锦 杨张阳 于 2020-05-14 设计创作，主要内容包括：本发明公开了一种观测井内地下水流向流速监测的光纤探测装置,包括装置外壳(1),装置外壳(1)内活动设置有电子罗盘(3),电子罗盘(3)的下部连有连接管(7),连接管(7)下部在垂直方向连有转向扇(6),电子罗盘(3)中心中空设置,钢管(8)穿过电子罗盘(3)中心,钢管(8)与装置外壳(1)固定连接,钢管(8)用于固定光纤(2),钢管(8)和光纤(2)穿过连接管(7),装置外壳(1)的下端连有光纤支架(10),光纤支架(10)用于固定光纤(2)的下部端点。本发明提供的一种观测井内地下水流向流速监测的光纤探测装置,成本较低,不易受周围电磁环境的干扰,比普通探头更为精准稳定。(The invention discloses an optical fiber detection device for monitoring the flow direction and the flow speed of underground water in an observation well, which comprises a device shell (1), wherein an electronic compass (3) is movably arranged in the device shell (1), the lower part of the electronic compass (3) is connected with a connecting pipe (7), the lower part of the connecting pipe (7) is connected with a steering fan (6) in the vertical direction, the center of the electronic compass (3) is arranged in a hollow manner, a steel pipe (8) penetrates through the center of the electronic compass (3), the steel pipe (8) is fixedly connected with the device shell (1), the steel pipe (8) is used for fixing an optical fiber (2), the steel pipe (8) and the optical fiber (2) penetrate through the connecting pipe (7), the lower end of the device shell (1) is connected with an optical fiber support (10), and the. The optical fiber detection device for monitoring the flow direction and the flow speed of underground water in the observation well, provided by the invention, has the advantages of low cost, difficulty in being interfered by the surrounding electromagnetic environment and higher accuracy and stability than a common probe.)

1. The utility model provides an optical fiber detection device of underground water flow direction velocity monitoring in observation well which characterized in that: comprises a device shell (1), an electronic compass (3) is movably arranged in the device shell (1), the lower part of the electronic compass (3) is connected with a connecting pipe (7), the lower part of the connecting pipe (7) is connected with a steering fan (6) in the vertical direction, the center of the electronic compass (3) is arranged in a hollow way, the steel pipe (8) passes through the center of the electronic compass (3), the steel pipe (8) is fixedly connected with the device shell (1), the steel pipe (8) is used for fixing the optical fiber (2), the steel tube (8) and the optical fiber (2) pass through the connecting tube (7), the lower end of the device shell (1) is connected with an optical fiber support (10), the optical fiber support (10) is used for fixing the lower end point of the optical fiber (2), the upper part of the optical fiber (2) and the electronic compass (3) are in communication connection with a ground information processing control system (9) arranged outside the device shell (1).

2. The optical fiber detection device for monitoring the flowing speed of underground water flow according to claim 1, wherein: be provided with concave rail (4) in device shell (1), inlay in concave rail (4) and have ball (5), ball (5) with the outside contact of electron compass (3).

3. The optical fiber detection device for monitoring the flowing speed of underground water flow according to claim 2, wherein: the concave rail (4) is positioned on the upper side, the lower side and the side wall of the electronic compass (3).

4. The optical fiber detection device for monitoring the flowing speed of underground water flow according to claim 1, wherein: the optical fiber support (10) is of a steel pipe structure.

5. The optical fiber detection device for monitoring the flowing speed of underground water flow according to claim 1, wherein: the steel pipe (8) and the center of the electronic compass (3) are arranged in a sealing way.

6. The optical fiber detection device for monitoring the flowing speed of underground water flow according to claim 1, wherein: the connecting pipe (7) is made of stainless steel.

Technical Field

The invention relates to an optical fiber detection device for monitoring the flow direction and the flow velocity of underground water in an observation well, and belongs to the technical field of hydrogeological parameter monitoring.

Background

The dam underground water observation well can be used for observing the hydrogeological condition near a dam, at present, underground water flow direction measuring methods are more, the traditional methods mainly comprise a pumping test method and a tracing method, and the methods are not suitable for single-well monitoring and are time-consuming and labor-consuming. The tracing method includes a radioactive isotope tracing method, a potential difference method, a heat tracing method and the like. Radioactive substances required by the radioactive isotope tracing method may cause harm to human bodies and the environment. The tracer used in the tracing method can perform physical and chemical reactions such as ion exchange, adsorption, precipitation and the like with underground water and rock-soil mass, and the measuring result is influenced. And the accuracy requirement of the thermal tracing method on the thermosensitive element is higher. Neutron activation and the like are technologies, but the cost of neutron activation is high and protective measures are required.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and provide the optical fiber detection device for monitoring the flow velocity of the underground water flow in the observation well, which has lower cost, is not easily interfered by the surrounding electromagnetic environment and is more accurate and stable than a common probe.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

the utility model provides an optical fiber detection device of groundwater flow direction velocity of flow monitoring in observation well, includes the device shell, device shell internalization is provided with the electron compass, the lower part of electron compass even has the connecting pipe, the connecting pipe lower part even has the steering fan in the vertical direction, electron compass center cavity sets up, and the steel pipe passes electron compass center, the steel pipe with device shell fixed connection, the steel pipe is used for fixed optic fibre, steel pipe and optic fibre pass the connecting pipe, the lower extreme of device shell even has the fiber support, the fiber support is used for fixing the lower part extreme point of optic fibre, optic fibre upper portion and electron compass are in the outer ground information processing control system communication of device shell links to each other.

A concave rail is arranged in the device shell, balls are embedded in the concave rail, and the balls are in contact with the outer side of the electronic compass.

The concave rail is positioned on the upper side, the lower side and the side wall of the electronic compass.

The optical fiber support is of a steel tube structure.

The steel pipe and the center of the electronic compass are arranged in a sealing mode.

The connecting pipe is made of stainless steel.

The invention has the beneficial effects that: the optical fiber detection device for monitoring the flow direction and the flow velocity of underground water in the observation well, provided by the invention, overcomes the defect that the common probe can only detect basic water quality information and cannot judge the water flow direction, and is convenient for accurately determining the water flow direction, the stress condition and other data of a detection area; the problem that the depth range of the water used by a common probe is small is solved. (ii) a The optical fiber measurement is not easily interfered by the surrounding electromagnetic environment, and is more accurate and stable than a common probe; the device has the advantages of simple structure, integrated design, simple and convenient operation and no need of complicated manpower and material resource support.

Drawings

FIG. 1 is a schematic cross-sectional view of an optical fiber detection device for monitoring the flow direction and flow velocity of underground water in an observation well according to the present invention;

fig. 2 is a schematic view of the turning locus of the steering fan in the present invention.

The reference numbers in the figures are as follows: 1-a device housing; 2-an optical fiber; 3-an electronic compass; 4-groove track; 5-rolling balls; 6-a steering fan; 7-connecting pipe; 8-a steel pipe; 9-ground information processing control system; 10-fiber support.

Detailed Description

The present invention is further described with reference to the accompanying drawings, and the following examples are only for clearly illustrating the technical solutions of the present invention, and should not be taken as limiting the scope of the present invention.

As shown in fig. 1 and 2, the present invention provides an optical fiber detection device for monitoring the flow velocity of underground water in an observation well, which includes a device housing 1, wherein the device housing 1 protects internal equipment from damage caused by external force. The device shell 1 is internally and movably provided with an electronic compass 3, the electronic compass 3 is used for measuring the water flow direction, a hole is formed in the central position in a position avoiding the element, the hole is used for passing through an optical fiber 2 and a steel pipe 8, the steel pipe 8 penetrates through the center of the electronic compass 3, the steel pipe 8 is fixedly connected with the device shell 1, and the steel pipe 8 is welded on the device shell 1 and is used for fixing the optical fiber 2 and preventing the optical fiber 2 from being bent inside the device. The steel tube 8 is used for fixing the optical fiber 2, the steel tube 8 and the optical fiber 2 pass through the connecting tube 7, and the optical fiber 2 is used for data measurement and is arranged in the device shell 1 and the connecting tube 7.

And the inner side gap formed after the hole is opened is sealed to prevent water from entering. A concave rail 4 is arranged in the device shell 1, a ball 5 is embedded in the concave rail 4, and the ball 5 is in contact with the outer side of the electronic compass 3. The groove tracks 4 are located on the upper and lower sides and the side walls of the electronic compass 3. The lower part of the electronic compass 3 is connected with a connecting pipe 7, and the connecting pipe 7 is made of stainless steel. The lower part of the connecting pipe 7 is connected with a steering fan 6 in the vertical direction. The 4-groove track is used for fixing 5 the running track of the ball, and the groove track 4 and the ball 5 have extremely high sensitivity and limit the steering of the electronic compass 3, the connecting pipe 7 and the steering fan 6 together. The direction of the steering fan 6 is fixed to be the same as the direction of the electronic compass 3, and the blades of the steering fan 6 always point to the direction of the water flow along with the rotation of the water flow. The connecting pipe 7 is connected with the steering fan 6 and the electronic compass 3, so that the steering fan 6 and the electronic compass 3 rotate together, the inside of the connecting pipe 7 is hollow, and the optical fiber 2 and the steel pipe 8 are arranged at the hollow part and are not contacted with the inner wall of the pipe.

The lower end of the device shell 1 is connected with an optical fiber support 10, the optical fiber support 10 is used for fixing the lower end point of the optical fiber 2, the two ends of the optical fiber 2 exposed in the water body are limited together with the steel pipe 8 and play a certain protection role, and in order to enable the optical fiber support 10 to have the minimum influence on a water flow detection result, the optical fiber support 10 adopts a thin steel pipe as a material. The upper part of the optical fiber 2 and the electronic compass 3 are in communication connection with a ground information processing control system 9 arranged outside the device shell 1, and the ground information processing control system 9 is based on the BOTDR optical fiber sensing technology and is used for data processing of optical information.

The working principle of the optical fiber detection device for monitoring the flow direction and the flow speed of underground water in the observation well is as follows:

the various components of the device are mounted as shown in figures 1 and 2. The optical end part is forbidden to touch, all parts are ensured to be installed in place before measurement, a nearby available water body is used for testing, and measurement can be carried out after the detection is correct. The optical cable with the detection device is placed into a well, and the lowering length of the optical cable with data appearing for the first time, namely the underground water burial depth, is recorded. And (5) keeping the device stable, and carrying out data measurement.

Flow direction measurement: the method comprises the steps of starting measurement from the underground buried water surface by the first integral depth below the water surface, measuring a group of data at intervals of one meter, and recording after the degree is stabilized in each measurement. The actual operation can be carried out by operators according to other measurement schemes. When seepage water flows through the well, the water flow disturbs the steering fan 6 to enable the fan blades to point to the direction of the water flow, and the direction of the water flow is obtained by the electronic compass 3. The compass is pointed to the direction of the water flow, i.e. the direction of the water flow, and the opposite direction is the direction of the water flow.

Stress condition and temperature measurement:

the brillouin frequency shift fed back from the most exposed portion of the optical fiber 2 is processed by the surface information processing control system 9 to obtain information such as the strain condition and the length change measured at the optical end, and the stress distribution condition and the water temperature are derived from the strain condition and the thermal expansion of the optical fiber.

After the measurement is completed, the device is removed from the well.

With reference to the formula:

1. and (3) strain measurement:

wherein n is the refractive index of the fiber core; v_AIs the speed of sound; λ is the wavelength of the forward-transmitted light wave in free space; e is the elastic modulus of the optical fiber material; ρ is the fiber density; k is the Poisson's ratio; is strain of

Theories and practices prove that the Brillouin scattering frequency shift is related to material properties, is sensitive to strain and has a linear relation with the strain, and can be expressed as follows:

V_B(t)＝V_BO(1-αt)

in the formula V_B(t) is the frequency shift at strain t; v_BOFrequency shift in the absence of strain, α is a constant.

The frequency shift difference of the Brillouin scattering light is measured, so that the strain of a certain point can be obtained, and the stress condition of the optical fiber can be further known.

2. And (3) temperature measurement:

the influence of temperature on the density and the refractive index is realized through a thermal expansion effect, and the relationship between Brillouin frequency shift and temperature is as follows:

v_B(T)＝(1.1134+0.0001T)×10¹⁰

wherein v is_BIs the Brillouin frequency shift, and T is the temperature.

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.