CN210719251U - High-order long-range landslide early warning device based on deflection and moisture content - Google Patents
High-order long-range landslide early warning device based on deflection and moisture content Download PDFInfo
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Abstract
The high-position remote landslide early warning device based on the deformation and the water content comprises a fixed point type strain sensing optical cable arranged on a landslide body, wherein the fixed point type strain sensing optical cable is connected with a demodulating device, and the demodulating device is connected with a data acquisition and processing device. The fixed-point type strain sensing optical cable comprises an optical fiber core positioned in the center, a grating is engraved on the optical fiber core, the grating is in a free moving state, and after the fixed-point type strain sensing optical cable is exposed out of the optical fiber core through the annular incision, an adhesive is poured in the fixed-point type strain sensing optical cable to be cured with the optical fiber core to form a glue joint fixed point; carbon fiber wires are embedded in the fixed-point type strain sensing optical cable. The carbon fiber wire is connected with the data acquisition and processing device through the control module. The utility model discloses a lay the fixed point formula strain sensing optical cable on the landslide body, can real-time detection landslide deflection and moisture content to through the on-the-spot data that data acquisition and processing device will monitor transmit long-range server through GPS, the server carries out comprehensive judgement analysis to data again, infers stability.
Description
Technical Field
The utility model relates to a landslide monitoring technology field specifically is a high-order long-range landslide early warning device based on deflection and moisture content.
Background
The high-position remote landslide is a high-position landslide geological disaster, is cut from the upper part of a high and steep slope and forms a high altitude to accelerate falling, has an impact crushing effect and a dynamic erosion effect, leads a slide body to be disintegrated and crushed, and then is converted into high-speed remote debris flow sliding or debris flow flowing, and shovels and scrapes a lower rock-soil body, so that the volume is obviously increased.
At present, displacement monitoring is mostly adopted for landslide deformation, the application is wide, and the method mainly comprises the following steps:
①, a geodetic precision measurement method, which adopts a total station, a level, a theodolite and the like, can observe the absolute displacement of a landslide body, has high measurement precision and efficiency, is suitable for monitoring the landslide displacement in different deformation stages, and has large measurement workload, long period and low automation degree under the condition of limited terrain conditions (communication conditions) and meteorological conditions.
②, GPS monitoring method, easy to operate, all-weather, high precision, full automatic, but low measurement precision, not suitable for landslide deformation initial monitoring, and in high mountain area, satellite signal is easy to be sheltered, when multipath effect is serious, has certain influence on measurement result.
③ and BOTDR monitoring methods have the advantages of high measurement precision, strong applicability, good real-time stability, high price, poor field operability, high maintenance difficulty, easy breakage and difficult application to the middle and later stages of landslide monitoring.
④, INSAR and other non-contact methods have the advantages of large acquisition quantity, high precision and fast data acquisition, but the data processing is difficult, the data processing is difficult due to the large influence factors of vegetation, soil, water content and other environments, and the applicability is poor.
⑤, a seam measuring method has the advantages of quick investment, high precision, simple and visual method and reliable data, but has the defects of difficult instrument installation, no obvious cracks in many places and inapplicability to the middle and later periods of landslide deformation.
Disclosure of Invention
For solving the technical problem, the utility model provides a high-order long-range landslide early warning device based on deflection and moisture content through laying the fixed point formula strain sensing optical cable on the landslide body, can real-time detection landslide deflection and moisture content to through the parameter remote transmission that data acquisition and processing device will monitor for monitor terminal, effectively monitor the early warning to the landslide.
The utility model discloses the technical scheme who takes does:
the high-position remote landslide early warning device based on the deformation and the water content comprises a fixed-point type strain sensing optical cable arranged on a landslide body, wherein the fixed-point type strain sensing optical cable is connected with a demodulating device, and the demodulating device is connected with a data acquisition and processing device.
The fixed-point type strain sensing optical cable comprises an optical fiber core positioned in the center, a grating is engraved on the optical fiber core, the grating is in a free moving state, and after the fixed-point type strain sensing optical cable is exposed out of the optical fiber core through the annular incision, an adhesive is poured in the fixed-point type strain sensing optical cable to be cured with the optical fiber core to form a glue joint fixed point; carbon fiber wires are embedded in the fixed-point type strain sensing optical cable.
The carbon fiber wire is connected with the data acquisition and processing device through the control module.
The optical fiber cable core is sequentially wrapped with an armor layer, a braided layer and an outer sheath from an inner layer to an outer layer; the grating and the armor layer are in a free moving state, and the protective shell is sleeved on the glue joint fixed point.
The broadband light source is connected with the optical circulator through a first transmission optical fiber, the demodulating device is connected with the optical circulator through a second transmission optical fiber, and the optical circulator is connected with the optical fiber wire core.
The data acquisition and processing device is connected with the control module through a transmission cable.
The data acquisition and processing device comprises a computer, and the computer is connected with the wireless transmission module.
The device also comprises a first installation fixture, wherein the first installation fixture is used for arranging the fixed-point type strain sensing optical cable on the soft soil, the first installation fixture comprises a plurality of fixing pieces, and each fixing piece is provided with a clamping piece for fixing a glue joint fixed point.
The device also comprises a second mounting fixture, wherein the second mounting fixture is used for arranging the fixed-point strain sensing optical cable on a hard rock body and comprises an upper fastener and a lower fastener, the upper fastener is provided with a fixing hole and a semicircular groove, the lower fastener is provided with a screw hole and a fixing nail, and the lower fastener is provided with a blasting impact body; the semicircular groove is used for fixing a fixed point type strain sensing optical cable, so that the fixed glue is connected to a fixed point, the blasting impact body collides with the firing pin, the explosion is generated to push the fixing nail to a hard rock body, and the screw penetrates through the fixing hole to fix the upper fastener and the lower fastener.
The landslide mass is provided with a drill hole, and the fixed-point strain sensing optical cable is placed in the drill hole and used for soil mass layering quantitative monitoring of the deformation and the water content of the landslide mass; after the undisturbed soil is placed, clay balls are placed around the glue joint fixed points used by each layer of soil body, and the clay balls are used for driving the fixed point type strain sensing optical cable to generate strain change when the landslide zone slides downwards, so that the friction force between the fixed point type strain sensing optical cable and the landslide zone is increased.
The device also comprises a grating speed sensor, wherein the grating speed sensor comprises a first optical fiber unit, a second optical fiber unit, a shell, an equal-strength cantilever beam and a heavy hammer; a first grating unit and a second grating unit are respectively engraved on the first optical fiber unit and the second optical fiber unit; one end of the constant-strength cantilever beam is connected with the shell, and the other end of the constant-strength cantilever beam is connected with the heavy hammer; the first grating unit and the second grating unit are respectively and symmetrically connected to two sides of the equal-strength cantilever beam and used for offsetting the influence of temperature change on the grating units.
The landslide early warning method based on the deformation and the water content comprises the following steps:
when measuring the moisture content, the data acquisition processing apparatus passes through control module and stops heating after a plurality of times to carbon fiber silk heating one end time, and the change of continuous measurement temperature records the time that the temperature descends, and the time that the temperature descends is linear relation with the moisture content in the soil body, if moisture content in the landslide body exceeds the upper and lower limit threshold value that sets up, then data acquisition processing apparatus passes through wireless transmission module with moisture content data remote transmission for monitor terminal, realizes the early warning to the landslide moisture content.
When the deformation is measured, the landslide body generates displacement and drives a plurality of fixed point type strain sensing optical cables fixedly arranged on the landslide body to glue fixed points and move, so that the grating generates strain, the demodulation device adjusts a grating strain signal and transmits data to the data acquisition and processing device, the grating strain data and the landslide body displacement are in a linear relation, if the landslide body displacement exceeds the set upper and lower limit thresholds, the data acquisition and processing device remotely transmits the deformation data to the monitoring terminal through the wireless transmission module, and the landslide deformation early warning is realized.
The utility model relates to a high-order long-range landslide early warning device based on deflection and moisture content, technological effect as follows:
1) the fixed-point strain sensing optical cable is embedded with carbon fiber wires, so that the synchronous measurement of deformation and water content under any environment is realized, the multi-point landslide body measurement can be completed by one sensing optical cable, the water content measurement is considered, and the measurement device is simple to arrange.
2) First installation fixture, second installation fixture are used for on the landslide body weak soil, hard rock mass respectively, make the utility model discloses the device is applicable to the adverse circumstances that the landslide body is complicated, possesses the commonality.
3) The grating in the grating speed sensor is symmetrically bonded at the two ends of the constant-strength cantilever beam to offset the influence of temperature change on the grating, and the surface wave speed structural section of the test field area can be obtained by adopting a hammering or falling weight mode to excite the seismic signal, so that the development and distribution conditions of the underground medium and the geological structure in the detection field are judged.
4) The whole device automatically processes data through a computer, monitored parameters are remotely transmitted to a monitoring terminal server through a GPS, and the server comprehensively analyzes and processes the stability of landslide to judge the stability of the high-level remote landslide.
Drawings
FIG. 1 is a schematic diagram of construction of a transient surface wave method exploration site.
Fig. 2 is a schematic diagram of a grating speed sensor structure.
Fig. 3 is a schematic diagram of a device for laying fixed-point strain sensing optical cables on a landslide body.
FIG. 4 is a schematic diagram of the connection of the landslide deformation and water content testing and early warning device.
Fig. 5 is a schematic structural diagram of a fixed-point strain sensing optical cable.
Fig. 6 is a schematic view of a first mounting fixture.
Fig. 7 is a schematic view of a second mounting fixture.
Fig. 8 is a schematic structural diagram of a fixed-point strain sensing optical cable testing device.
FIG. 9 is a graph of spot cable strain versus wavelength change.
FIG. 10 is a plot of fixed point cable displacement versus micro-strain calibration.
FIG. 11 is a schematic diagram of downhole strain and moisture content testing of a set point cable.
FIG. 12 is a diagram illustrating the definition of local stability factor.
Detailed Description
Dividing a high-position remote landslide:
a. a plurality of groups of discontinuous structural surfaces are distributed on a geological disaster body, a thick layer blocky rock body is divided into cracked blocks, an obvious fracturing and bulging area is formed in an elevation interval, and particularly 2 groups of anti-inclination joint zones exist, so that the geological disaster body has a typical 'locking section' instability mechanism. The landslide mass slides out at a high position, and is continuously loaded and accumulated on the upper part of the slope mass, so that the instability of the residual slope rock-soil layer is caused and the residual slope rock-soil layer is converted into a pipeline type debris flow; after the debris flow slides to an old landslide accumulation body at the lower part of the slope at a high speed, the debris flow is converted into diffusion type debris flow scattering accumulation due to the fact that the front terrain is wide and the slope is slow, and the high-speed long-distance disaster mode is achieved. When the steep ridge has large rock high-position landslide, the dynamic erosion effect and the accumulation loading effect brought by the impact action should be considered, and particularly, when abundant underground water exists along the valley, the possibility of high-speed remote landslide is obviously increased. Therefore, in the investigation and investigation of geological disasters, a region of accumulation on a slope bank below the exit of a high-level rock landslide shear should be defined as a geological disaster risk region. In the geological disaster research, a statics theory is adopted to analyze the instability mechanism of the landslide, and a dynamic method is adopted to enhance the disaster mode research of the movement process.
b. Layering and quantifying the shallow rock-soil mass by adopting a transient surface wave method:
as shown in the schematic diagram of the transient surface wave method exploration field construction shown in FIG. 1, I is a seismic source, II is the ground, and ①, ②, ③ and ④ are grating speed sensors No. ① to No. ④ respectively.
The main reason for causing high and remote landslide is that the shallow weathered layer has a loose structure, and a large number of primary and secondary structural surfaces are easily formed in a side slope region, so that the soil body is uneven, and the instability phenomenon is easily caused under the rainfall condition. The thickness of different weathering layers needs to be found out firstly, and the positions needing to be monitored are defined for the weathering layers with different weathering degrees and thicknesses. When the elastic wave propagates in the layered medium, the elastic wave has a frequency dispersion characteristic, that is, the surface waves with different frequencies have different propagation speeds, and when the elastic wave propagates along the surface of the medium layer, the attenuation speed is slow, and when the elastic wave propagates in the medium, the attenuation speed is fast. The surface wave is closely related to the mechanical property of the soil layer during propagation, the propagation speed of the surface wave is basically similar to the wave speed of the shear wave, and the surface wave does not change greatly along with the Poisson ratio of the soil body.
The utility model discloses a change of face wave frequency dispersion characteristic analysis judgement underground space. The method comprises the steps of exciting seismic signals by adopting a hammering or falling weight mode, replacing a grating 1.2 in the landslide deformation and water content testing and early warning device in the figure 4 with a grating speed sensor for receiving the seismic signals, inverting acquired data by a data acquisition and processing device 3 to obtain dispersion curves of different measuring points, sorting and analyzing the data of the dispersion curves of all the points to obtain a surface wave speed structure section of a testing field area, and judging the development and distribution conditions of underground media and geological structures in the detection field.
c. Grating speed sensor:
the traditional transient surface wave method mostly adopts a seismic monitor or a geophone to detect, and a GS-20DX type geophone produced by GeoSpac company in America is most widely applied, but the electrical signal return attenuation is large, the interference is easy to happen, and the multiplexing of multiple probes is difficult. The optical fiber sensor has the characteristics of being passive, anti-interference, strong in multiplexing capability and the like, has obvious advantages in a transient surface wave method, and becomes a hotspot of recent research. Fig. 2 is a schematic diagram of a grating speed sensor structure.
The grating speed sensor comprises a first optical fiber unit 5.1, a second optical fiber unit 5.2, a shell 5.3, an equal-strength cantilever beam 5.4 and a heavy hammer 5.5, wherein a first grating unit 5.6 and a second grating unit 5.7 are respectively engraved on the first optical fiber unit 5.1 and the second optical fiber unit 5.2. The shell 5.3 is made of stainless steel, and the weight 5.5 is made of a stainless steel ball.
The wide end of the equal strength cantilever 5.4 and the stainless steel shell are welded by laser, the narrow end is welded by laser with the stainless steel ball, the first grating unit 5.6 and the second grating unit 5.7 are symmetrically welded at the two ends of the equal strength cantilever 5.4, in order to counteract the influence of temperature change on the grating, when the sensor receives the vibration signal generated by hammering, the stainless steel ball is influenced by the speed change to reciprocate in the vertical direction, so that the stress change of the first grating unit 5.6 and the second grating unit 5.7 at the two ends of the equal strength cantilever 5.4 is caused, the reflectivity of the corresponding wavelength is changed, the relative information of vibration can be extracted by detecting the change of light intensity, the acquired data can be inverted, the frequency dispersion curves of different measuring points can be obtained, the data of the frequency dispersion curves of each point can be sorted and analyzed, the surface wave speed structure section of the test field can be obtained, thereby judging the development and distribution conditions of the underground medium and the geological structure in the detection field.
Secondly, the arrangement of the deformation and the water content on the landslide body:
as shown in fig. 3, wherein a is a landslide body, b is a landslide band, c is a landslide surface, d is a landslide block, and e is a stabilizer;
3 is a data acquisition and processing device, 12 is a drill hole, and 1 is a fixed point type strain sensing optical cable.
Thirdly, landslide deformation and water content testing and early warning device:
as shown in fig. 4, the system comprises a fixed point type strain sensing optical cable 1 arranged on a landslide body, wherein the fixed point type strain sensing optical cable 1 is connected with a demodulating device 2, and the demodulating device 2 is connected with a data acquisition processing device 3.
The broadband light source 5 is connected with the optical circulator 7 through the first transmission optical fiber 6, the demodulation device 2 is connected with the optical circulator 7 through the second transmission optical fiber 8, and the optical circulator 7 is connected with the optical fiber wire core 1.1.
The data acquisition and processing device 3 is connected with the control module 4 through the transmission cable 9, and the control module 4 controls the temperature rise time of the carbon fiber yarn 1.4.
The data acquisition and processing device 3 comprises a computer, and the computer is connected with the wireless transmission module through a network cable/RS 232/RS 485. The wireless transmission module adopts a 4g communication module GPRS/DTU data acquisition terminal.
The demodulation device 2 comprises a CCD demodulation module and a CCD detector array. In fig. 4, a broadband light source 5 emits a light source, the wavelength reflected by each grating changes with the change of temperature or strain, a CCD module demodulates the gratings, the CCD demodulation module diffracts emitted light by using a transmission type Volume Phase Grating (VPG), images the light on a CCD detector array with 512 pixels, and acquires the peak wavelength of the reflected signal by high-speed signal acquisition and processing, the demodulation frequency of the CCD demodulation module reaches 5000Hz, and the real-time detection requirements of landslide deformation and water content can be met.
As shown in fig. 5, the fixed-point type strain sensing optical cable 1 includes an optical fiber core 1.1 located in the center, a grating 1.2 is inscribed on the optical fiber core 1.1, the grating 1.2 is in a free-moving state, after the optical fiber core 1.1 is exposed through the annular incision, an adhesive 1.3 is poured in and is cured with the optical fiber core 1.1 to form a glue joint fixed point 1.9. Carbon fiber wires 1.4 are embedded in the fixed-point type strain sensing optical cable 1.
The fixed point type strain sensing optical cable 1 is connected with a broadband light source 5;
the carbon fiber wires 1.4 are connected with the data acquisition and processing device 3 through the control module 4.
The optical fiber wire core 1.1 is sequentially wrapped with an armor layer 1.5, a braided layer 1.6 and an outer sheath 1.7 from an inner layer to an outer layer; the grating 1.2 and the armor layer 1.5 are in a free moving state, and the protective shell 1.8 is sleeved on the glue joint fixed point 1.9.
The fixed point type strain sensing optical cable 1 is a strain sensing optical cable which generates strain by utilizing the change of external tension or temperature received by a grating, the grating 1.2 and an armor layer 1.5 are in a free moving state, and then the grating 1.2, the armor layer 1.5 and an outer sheath 1.7 are fixed by a certain distance, so that the discontinuous and nonuniform segmentation of space is realized, and the strain measurement result can directly calculate the deformation and the temperature. The landslide monitoring is considered, the fixed-point distance is 2 meters, the grating 1.2 is wound with the armor layer 1.5, the braid layer 1.6 and the outer sheath 1.7, and the cabling process comprises the following steps: with polyether elasticity TPU through cable machine extrusion even scribble around optical fiber core 1.1 and weaving layer 1.6, through the water-chilling, spout rectangle and the rice mark of 50 millimeters long and 8 millimeters wide according to 2 meters intervals through the ink jet numbering machine, the cable is that the black colour of the mark that spouts is white, makes things convenient for the quick position of finding out the rice mark of site operation. After the cable is pulled in, 2 meters of the outer sheath 1.7 are peeled off by 40 millimeters, and the improved epoxy resin adhesive is filled inside, and 2 semicircular clips are preferably sleeved on the improved epoxy resin adhesive to serve as a protective shell 1.8.
Fourthly, installation and test of the fixed-point type strain sensing optical cable 1:
(1): as shown in fig. 6, the apparatus further comprises a first mounting fixture 10 for arranging the fixed-point strain sensing optical cable 1 on soft soil, wherein the first mounting fixture 10 comprises a plurality of fixing members 10.1, and each fixing member 10.1 is provided with a clamping piece 10.2 for fixing the glue joint point 1.9. The fixing piece 10.1 is made of angle iron, and the clamping piece 10.2 is a clamp with a screw and used for fixing the angle iron and the fixed-point type strain sensing optical cable 1 together. The fixed point type strain sensing optical cable 1 is laid on a landslide surface through the fixture in the figure 6 according to the routing of the optical cable in the figure 1, when the landslide surface is deformed, the landslide drives the angle iron to pull the grating 1.2 in the optical cable, the grating 1.2 generates micro-strain, and the optical fiber is arranged on soft soil seriously weathered.
(2): as shown in fig. 7, the device further includes a second installation fixture 11, which is used for arranging the fixed-point strain sensing optical cable 1 on a hard rock body, the second installation fixture 11 includes an upper fastener 11.1 and a lower fastener 11.2, the upper fastener 11.1 is provided with a fixing hole 11.3, a semicircular groove 11.4, the lower fastener 11.2 is provided with a screw hole 11.5 and a fixing nail 11.6, and the lower fastener 11.2 is provided with a blasting impact body 11.7. The semicircular groove 11.4 is used for fixing the fixed point type strain sensing optical cable 1, so that the fixed glue joint fixed point 1.9 is fixed, the blasting impact body 11.7 collides with the firing pin to generate explosion to push the fixing nail 11.6 into a hard rock body, and the screw penetrates through the fixing hole 11.3 to fix the upper fastener 11.1 and the lower fastener 11.2. The fixing hole 11.3 is a round hole with the diameter of 10 mm, and the upper fastener 11.1 is a square iron plate. The screw hole 11.5 is an M10 screw hole, and the fixing nail 11.6 is a steel nail.
In the past, fixing a fixed point optical cable on a steep rock wall is a very difficult thing, and the percussion drill is too heavy and inconvenient to operate, and the utility model discloses adopt the very easy installation of the method of figure 7. The installation process is that the steel nail is firstly placed at a designated position and is impacted by a firing pin matched with the blasting impact body 11.7 to generate explosion to push the steel nail into rock soil, the upper fastener 11.1 and the lower fastener 11.2 are fixed by screws, and the screws are screwed after 200 micro-strain force is applied to the glue joint fixed point 1.9 during installation.
(3): as shown in FIG. 11, 1 # 2 # and 3 # 358 # indicate a site. And (3) drilling and laying process: after drilling, a fixed point type strain sensing optical cable 1 is placed according to a graph 11, clay balls are placed around each layer of fixed point optical cable after undisturbed soil is placed, and then the undisturbed soil and the clay balls are placed, wherein the clay balls are used for driving the strain change of the fixed point type strain sensing optical cable 1 when a landslide zone slides down, and increasing the friction force between the fixed point type strain sensing optical cable 1 and the landslide zone. The purpose of placing undisturbed soil is to be capable of measuring the water content and truly reflecting the water content of each stratum. The principle of measuring the water content is that firstly, the carbon fiber wires 1.4 in the fixed-point type strain sensing optical cable 1 are heated for 1 minute, then the heating is stopped, the temperature change is continuously measured, and the temperature reduction time and the water content in the soil body are in a linear relation.
Fifthly, calibrating and testing the fixed-point strain sensing optical cable 1:
as shown in fig. 8, the calibration test includes: adjusting screw 13, fixing nut 14, slider 15, fixed angle 16, demodulating equipment 2, steel sheet 17.
The fixed point A of the fixed point type strain sensing optical cable 1 is fixed on the sliding block 15, the fixed point B of the fixed point type strain sensing optical cable 1 is fixed on the fixed angle iron 16, and the fixed point type strain sensing optical cable 1 is connected with the demodulating device 2. After the adjusting screw 13 passes through the fixing nut 14, the end part of the adjusting screw 13 is connected and matched with the sliding block 15, and the end part of the adjusting screw 13 and the sliding block 15 can rotate in the sliding block 15 and can drive the sliding block 15 to horizontally move left and right along the steel plate 17.
After the optical fiber is tensioned at the fixing point A, the adjusting screw 13 drives the sliding block 15 to move leftwards, the fixing point A moves leftwards, the change of the wavelength and the strain is recorded after 1 mm of movement each time, and the distance between the fixing nut 14 and the fixing point A is measured by a caliper. The test results are shown in table 1, the curve of fig. 9 is drawn from table 1, and the graph 9 shows that the test accuracy reaches 99.9%.
Table 1 fixed point cable test data table, in table 1, the Ax column is the unit of change in displacement in millimeters.
As can be seen from fig. 9 and 10, the linearity of the calibration curve is very good, and both the linearity and the linearity reach more than 99.9%.
Sixthly, analyzing the local stability of the high-position remote landslide:
and establishing a local stability coefficient map of the landslide body according to the landslide induced by the change of the water content of the rock-soil body, as shown in figure 12. In fig. 12, the solid line stress circle is the stress state of a point in the landslide body, and it is known from the mohr-coulomb principle that if the soil body at the point is damaged by shearing, the ultimate stress state of the point should intersect with the damage envelope line at the point B, and the shearing force value at the point B represents the soil body pole at the pointThe strength is limited. Total principal stress (σ ') in landslide bodies in general'1、σ'3) Mainly influenced by the geometry of the landslide body and the self gravity. For a given model of the sliding mass, its geometry is unchanged and the principal stresses associated with it are unchanged. Compared with the change of the absorption stress in the rainfall seepage process, the influence of the landslide body on the total main stress is relatively small. Therefore, under the rainfall action of the high-position remote landslide, the stress change in the landslide body is mainly caused by the absorption stress, and the Moire circle can be caused to move leftwards. As the water cut increases, the soil will slip as the moire circle moves to point C, which is tangential to the failure envelope.
The stability coefficient of a certain point in the landslide body can be represented by the ratio of the shear strength of the rock-soil body to the corresponding shear stress. Accordingly, the stability factor in FIG. 12 can be found:
by means of a trigonometric similarity relationship, an extended moire-coulomb intensity criterion relationship can be introduced:
the local stability analysis implementation process calculation process: adopting Seep/W to complete landslide model establishment and finite element grid division, and calculating pore water pressure values of each point of the landslide soil body at different time points during rainfall; leading the water pressure value of each Seep/W node into a Sigma/W module, completing seepage stress coupling calculation of each node, and obtaining effective stress values of each point of the landslide body at different times; deriving effective stress values corresponding to all nodes in a Sigma/W module in all rainfall time periods, and calculating corresponding stability coefficients in an Excel table based on a formula (2); and (3) specifying a landslide boundary by adopting Surfer software, and interpolating the stability coefficients obtained at each point in the Excel table to generate a local stability coefficient contour map.
Claims (9)
1. High-order long-range landslide early warning device based on deflection and moisture content is including laying fixed point formula strain sensing optical cable (1) on the landslide body, its characterized in that: the fixed point type strain sensing optical cable (1) is connected with the demodulating device (2), and the demodulating device (2) is connected with the data acquisition and processing device (3);
the fixed-point strain sensing optical cable (1) comprises an optical fiber core (1.1) positioned in the center, a grating (1.2) is engraved on the optical fiber core (1.1), the grating (1.2) is in a free-moving state, after the optical fiber core (1.1) is exposed out of the fixed-point strain sensing optical cable (1) through a circular incision, an adhesive (1.3) is poured in the fixed-point strain sensing optical cable and the optical fiber core (1.1) are cured to form a glue joint fixed point (1.9); carbon fiber wires (1.4) are embedded in the fixed-point strain sensing optical cable (1);
the carbon fiber wire (1.4) is connected with the data acquisition and processing device (3) through the control module (4).
2. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the optical fiber cable core (1.1) is sequentially wrapped with an armor layer (1.5), a braided layer (1.6) and an outer sheath (1.7) from an inner layer to an outer layer; the grating (1.2) and the armor layer (1.5) are in a free moving state, and the protective shell (1.8) is sleeved on the glue joint fixed point (1.9).
3. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the broadband light source (5) is connected with the optical circulator (7) through the first transmission optical fiber (6), the demodulation device (2) is connected with the optical circulator (7) through the second transmission optical fiber (8), and the optical circulator (7) is connected with the optical fiber wire core (1.1).
4. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the data acquisition and processing device (3) is connected with the control module (4) through a transmission cable (9).
5. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the data acquisition and processing device (3) comprises a computer, and the computer is connected with the wireless transmission module.
6. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the device further comprises a first mounting fixture (10) used for arranging the fixed-point strain sensing optical cable (1) on soft soil, wherein the first mounting fixture (10) comprises a plurality of fixing pieces (10.1), and a clamping piece (10.2) used for fixing the glue joint fixed point (1.9) is arranged on each fixing piece (10.1).
7. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the device also comprises a second mounting fixture (11) which is used for arranging the fixed-point strain sensing optical cable (1) on a hard rock body, wherein the second mounting fixture (11) comprises an upper fastener (11.1) and a lower fastener (11.2), the upper fastener (11.1) is provided with a fixing hole (11.3), a semicircular groove (11.4), the lower fastener (11.2) is provided with a screw hole (11.5) and a fixing nail (11.6), and the lower fastener (11.2) is provided with a blasting impact body (11.7);
the semicircular groove (11.4) is used for fixing the fixed point type strain sensing optical cable (1), so that a fixed glue joint fixed point (1.9) is fixed, a blasting impact body (11.7) collides with a firing pin to generate explosion to push a fixing nail (11.6) to a hard rock body, and a screw penetrates through a fixing hole (11.3) to fix an upper fastener (11.1) and a lower fastener (11.2).
8. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the landslide mass is provided with a drill hole (12), and the fixed-point strain sensing optical cable (1) is placed in the drill hole (12) and used for monitoring the deformation and the water content of the landslide mass in a layering and quantitative manner;
after the undisturbed soil is placed, clay balls are placed around the glue joint fixed points (1.9) used by each layer of soil body, and the clay balls are used for driving the fixed point type strain sensing optical cable (1) to generate strain change when the landslide zone slides downwards, so that the friction force between the fixed point type strain sensing optical cable (1) and the landslide zone is increased.
9. The high-position remote landslide early warning device based on deformation and water content as claimed in claim 1, wherein: the device also comprises a grating speed sensor, wherein the grating speed sensor comprises a first optical fiber unit (5.1), a second optical fiber unit (5.2), a shell (5.3), an equal-strength cantilever beam (5.4) and a heavy hammer (5.5); a first grating unit (5.6) and a second grating unit (5.7) are respectively engraved on the first optical fiber unit (5.1) and the second optical fiber unit (5.2);
one end of the constant-strength cantilever beam (5.4) is connected with the shell (5.3), and the other end is connected with the heavy hammer (5.5); the first grating unit (5.6) and the second grating unit (5.7) are respectively and symmetrically connected to two sides of the constant-strength cantilever beam (5.4) and used for offsetting the influence of temperature change on the grating units.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110836690A (en) * | 2019-11-06 | 2020-02-25 | 中国地质调查局水文地质环境地质调查中心 | High-position remote landslide early warning device and method based on deformation and water content |
| US20230213397A1 (en) * | 2022-01-05 | 2023-07-06 | National Central University | Stratum deformation monitoring device, system and method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110836690A (en) * | 2019-11-06 | 2020-02-25 | 中国地质调查局水文地质环境地质调查中心 | High-position remote landslide early warning device and method based on deformation and water content |
| US20230213397A1 (en) * | 2022-01-05 | 2023-07-06 | National Central University | Stratum deformation monitoring device, system and method |
| US12013297B2 (en) * | 2022-01-05 | 2024-06-18 | National Central University | Stratum deformation monitoring device, system and method |
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