阅读说明：本技术 一种光纤光栅孔隙水压力传感器 (Fiber grating pore water pressure sensor ) 是由 左文荣 陆钊 尚新乐 邱亚军 周文龙 翁振 张良 游红玲 章萍 郑创峰 黄飞飞 于 2019-10-10 设计创作，主要内容包括：本发明提供了一种光纤光栅孔隙水压力传感器,包括传感器保护壳、与外部土体紧密接触的透水石过滤装置和光纤光栅传感器测量装置,所述透水石过滤装置和光纤光栅传感器测量装置分别设置在所述传感器保护壳之内,所述光纤光栅传感器测量装置包括应变光纤光栅传感器元件和弹性膜,所述应变光纤光栅传感器元件嵌固在所述弹性膜之内,所述透水石过滤装置设置在所述弹性膜的上部,所述透水石过滤装置、弹性膜之间设有液压腔,所述液压腔中充满了传压水。本发明的有益效果是：可以高效,快速地测量到孔隙水压力真实值。(The invention provides a fiber bragg grating pore water pressure sensor which comprises a sensor protective shell, a permeable stone filtering device and a fiber bragg grating sensor measuring device, wherein the permeable stone filtering device and the fiber bragg grating sensor measuring device are in close contact with an external soil body and are respectively arranged in the sensor protective shell, the fiber bragg grating sensor measuring device comprises a strain fiber bragg grating sensor element and an elastic membrane, the strain fiber bragg grating sensor element is embedded and fixed in the elastic membrane, the permeable stone filtering device is arranged on the upper portion of the elastic membrane, a hydraulic cavity is arranged between the permeable stone filtering device and the elastic membrane, and pressure transfer water is filled in the hydraulic cavity. The invention has the beneficial effects that: the real value of the pore water pressure can be measured efficiently and quickly.)

1. A fiber grating pore water pressure sensor is characterized in that: the device comprises a sensor protective shell, a permeable stone filtering device and a fiber bragg grating sensor measuring device, wherein the permeable stone filtering device and the fiber bragg grating sensor measuring device are in close contact with an external soil body and are respectively arranged in the sensor protective shell, the fiber bragg grating sensor measuring device comprises a strain fiber bragg grating sensor element and an elastic membrane, the strain fiber bragg grating sensor element is embedded and fixed in the elastic membrane, the permeable stone filtering device is arranged at the upper part of the elastic membrane, a hydraulic cavity is arranged between the permeable stone filtering device and the elastic membrane, the hydraulic cavity is filled with pressure transfer water, the water in a soil sample transfers the water pressure in the soil sample to the pressure transfer water in the hydraulic cavity through the permeable stone filtering device and further transfers the water pressure to the surface of the elastic membrane at the lower part of the hydraulic cavity, and when the pressure on the elastic membrane changes, the elastic membrane deforms, the strain fiber grating sensor element inside the strain fiber grating sensor element deforms along with the elastic membrane and generates strain, and the pressure on the elastic membrane is obtained through strain measurement of the strain fiber grating sensor element, namely the pore water pressure in the hydraulic cavity.

2. The fiber grating pore water pressure sensor of claim 1, wherein: and a cavity is arranged below the elastic membrane, when the pressure of pressure-transmitting water in the hydraulic cavity is increased, the pressure on the elastic membrane is increased, the cavity below the elastic membrane generates corresponding deformation, and the increased value of the pore water pressure can be obtained through the measurement of the strain fiber grating sensor element.

3. The fiber grating pore water pressure sensor of claim 2, wherein: the permeable stone filtering device, the hydraulic cavity, the elastic membrane and the cavity are all circular and have the same diameter.

4. The fiber grating pore water pressure sensor of claim 3, wherein: the strain fiber grating sensor element is positioned at the center of the circle of the elastic membrane.

5. The fiber grating pore water pressure sensor of claim 1, wherein: the permeable stone filtering device comprises a permeable stone which is a porous medium separating soil particles in a tested soil sample from water in the soil particles.

Technical Field

The invention relates to a sensor, in particular to a fiber grating pore water pressure sensor.

Background

In recent years, the research and application of fiber grating sensors have attracted much attention, and compared with the traditional sensing measurement technology, the fiber grating sensing technology has many obvious advantages. For example, the fiber grating has the characteristics of flexible structural form, high temperature resistance, corrosion resistance, strong anti-electromagnetic interference capability, small volume, light weight and the like, and is widely applied to measurement of various physical quantities such as pressure, deformation, displacement, flow, volume, flow rate and the like.

At present, the design and processing method of the fiber bragg grating pore water pressure sensor is relatively lagged behind, and the measurement precision, response time, measurement error and the like of the pore water pressure cannot meet the monitoring requirements of water conservancy and civil engineering. Because the bare fiber grating sensing unit is very fine and has extremely small stress and temperature sensitivity coefficient, the bare fiber grating sensing unit cannot be directly used for measuring actual physical quantities such as water pressure, temperature, pressure and the like, the fiber grating sensing unit needs to be designed and packaged according to the measuring environment and the measured physical quantities, and the fiber grating pore water pressure sensor capable of meeting the measuring requirements is processed. Meanwhile, the existing fiber grating pore water pressure sensor has preliminary research results, but the test effect of the existing fiber grating sensor for measuring water pressure is required to be improved, and the existing fiber grating sensor for measuring water pressure is not ideal in the aspects of measuring water pressure accuracy, precision, lag time and the like. Therefore, there is a need to develop a fiber bragg grating pore water pressure sensor which can measure the true value of the pore water pressure efficiently and quickly.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a fiber grating pore water pressure sensor.

The invention provides a fiber grating pore water pressure sensor, which comprises a sensor protective shell, a permeable stone filtering device and a fiber grating sensor measuring device, wherein the permeable stone filtering device and the fiber grating sensor measuring device are in close contact with an external soil body respectively, the fiber grating sensor measuring device comprises a strain fiber grating sensor element and an elastic membrane, the strain fiber grating sensor element is embedded and fixed in the elastic membrane, the permeable stone filtering device is arranged at the upper part of the elastic membrane, a hydraulic cavity is arranged between the permeable stone filtering device and the elastic membrane, the hydraulic cavity is filled with pressure transfer water, the water in a soil sample transmits the water pressure in the soil sample to the pressure transfer water in the hydraulic cavity through the permeable stone filtering device and further transmits the water pressure to the surface of the elastic membrane at the lower part of the hydraulic cavity, when the pressure on the elastic membrane changes, the elastic membrane deforms, the strain fiber grating sensor element inside the elastic membrane deforms along with the elastic membrane and generates strain, and the pressure on the elastic membrane is obtained through strain measurement of the strain fiber grating sensor element, namely the pore water pressure in the hydraulic cavity.

As a further improvement of the invention, a cavity is arranged below the elastic membrane, when the pressure of the pressure-transmitting water in the hydraulic cavity is increased, the pressure on the elastic membrane is increased, the cavity below the elastic membrane generates corresponding deformation, and the increased value of the pore water pressure can be obtained through the measurement of the strain fiber grating sensor element.

As a further improvement of the invention, the permeable stone filtering device, the hydraulic cavity, the elastic membrane and the cavity are all circular and have the same diameter.

As a further improvement of the invention, the strain fiber grating sensor element is positioned at the center of the circle of the elastic membrane.

As a further improvement of the invention, the permeable stone filtering device comprises a permeable stone which is a porous medium for separating soil particles in the tested soil sample from water in the soil particles.

The invention has the beneficial effects that: through the scheme, the true value of the pore water pressure can be measured efficiently and quickly.

Drawings

FIG. 1 is a schematic diagram of a fiber grating pore water pressure sensor according to the present invention.

Fig. 2 is a schematic diagram of a fiber grating pore water pressure sensor in a top view direction.

Detailed Description

The invention is further described with reference to the following description and embodiments in conjunction with the accompanying drawings.

As shown in fig. 1 to 2, a fiber bragg grating pore water pressure sensor comprises a sensor protection shell 108, a permeable stone filtering device 101 and a fiber bragg grating sensor measuring device, wherein the permeable stone filtering device 101 and the fiber bragg grating sensor measuring device are in close contact with an external soil body, the permeable stone filtering device 101 and the fiber bragg grating sensor measuring device are respectively arranged in the sensor protection shell 108, the fiber bragg grating sensor measuring device comprises a strain fiber bragg grating sensor element 105 and an elastic membrane 104, the strain fiber bragg grating sensor element 105 is embedded and fixed in the elastic membrane 104, the permeable stone filtering device 101 is arranged on the upper portion of the elastic membrane 104, a hydraulic cavity 102 is arranged between the permeable stone filtering device 101 and the elastic membrane 104, the hydraulic cavity 102 is filled with pressure transfer water 103, water in a soil sample transfers water pressure in the soil sample to the pressure transfer water 103 in the hydraulic cavity 102 through the permeable stone filtering device 101, and further transmitted to the surface of the elastic membrane 104 at the lower part of the hydraulic pressure chamber 102, when the pressure on the elastic membrane 104 changes, the elastic membrane 104 deforms, the strain fiber grating sensor element 105 inside the elastic membrane 104 deforms and generates strain, and the pressure on the elastic membrane 104, namely the pore water pressure in the hydraulic pressure chamber 102, is obtained by measuring the strain of the strain fiber grating sensor element 105.

As shown in fig. 1 to fig. 2, a cavity 107 is disposed below the elastic membrane 104, when the pressure of the pressure-transmitting water 103 in the hydraulic chamber 102 increases, the pressure on the elastic membrane 104 increases, and the cavity 107 below the elastic membrane 104 deforms correspondingly, so that the increased value of the pore water pressure can be obtained through measurement of the strain fiber grating sensor element 105.

As shown in fig. 1 to 2, the permeable stone filtering device 101, the hydraulic pressure chamber 102, the elastic membrane 104 and the cavity 107 are all circular and have the same diameter.

As shown in fig. 1 to 2, the strain fiber grating sensor element 105 is located at the center of the elastic membrane 104.

As shown in fig. 1 to 2, the permeable stone filtering device 101 includes a permeable stone which is a porous medium separating soil particles in a measured soil sample from water in the soil particles.

As shown in fig. 1 to 2, a sensor lower base 109 is connected to the bottom of a sensor protection shell 108, the sensor protection shell 108 and the sensor lower base 109 enclose to form a circular groove, a porous stone filtering device 101, a hydraulic pressure cavity 102, an elastic membrane 104 and a cavity 107 are stacked in the circular groove from top to bottom, a strain fiber grating sensor element 105 is connected to the boundary through a sensor signal fiber 106, and the sensor signal fiber 106 is protected through a sleeve 110 and a fiber protection sleeve 111.

According to the fiber bragg grating pore water pressure sensor provided by the invention, the permeable stone is a porous medium which can separate soil particles in a measured soil sample from water in the soil particles, the soil particles are blocked outside the permeable stone, and the water in the soil sample transfers the water pressure in the soil sample to liquid in the hydraulic cavity 102 through the permeable stone and further transfers the water pressure to the surface of the elastic membrane 104 at the lower part of the hydraulic cavity 102. The elastic membrane 104 is embedded with a strain fiber grating sensor element 105, when the pressure on the elastic membrane 104 changes, the elastic membrane 104 deforms, the strain fiber grating sensor element 105 inside the elastic membrane 104 deforms and generates strain, and the pressure on the elastic membrane 104, namely the pore water pressure in the hydraulic cavity 102, can be obtained by measuring the strain of the strain fiber grating sensor element 105. The cavity 107 is arranged below the elastic membrane 104, so when the pressure of the pressure-transmitting water in the hydraulic pressure chamber 102 is increased, the pressure on the elastic membrane 104 is increased, the corresponding deformation is generated on the cavity 107 below the elastic membrane 104, and the increased value of the pore water pressure can be obtained through the measurement of the strain fiber grating sensor element 105.

According to the fiber bragg grating pore water pressure sensor provided by the invention, the function of measuring the pore water pressure in a soil sample can be realized through the permeable stone filtering device 101 and the fiber bragg grating sensor measuring device; the permeable stone is a porous medium, so that soil particles in the soil sample to be measured can be separated from water in the soil particles, the water in the soil sample transmits the water pressure in the soil sample to the liquid in the hydraulic cavity 102 through the permeable stone and further transmits the water pressure to the surface of the elastic membrane 104 at the lower part of the hydraulic cavity 102, the pressure on the elastic membrane 104 can be obtained through strain measurement of the strain fiber grating sensor element 105, and the true value of the pore water pressure can be measured efficiently and quickly.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.