A method for integrated land and water rock movement observation based on an unmanned ship

Abstract

In view of the problem that it is difficult to carry out deformation monitoring of mining subsidence areas containing water bodies, the present invention designs a land-water integrated rock movement observation method based on an unmanned ship to conduct rock movement observation on mining subsidence areas containing water bodies. The three-dimensional laser scanning technology, GNSS technology, inertial navigation technology, depth sounder and other technologies are used for land-water integrated measurement through the unmanned ship, and the accuracy of the overlapping area between the integrated measurement results and the traditional measurement data is checked to ensure the accuracy of the integrated measurement. The present invention can not only effectively monitor the mining subsidence water accumulation area, but also be combined with the on-land monitoring results to ensure the integrity of the rock movement observation line, providing strong technical support for the subsequent mining and settlement monitoring work in the mining area.

Description

Technical Field

[0001] The present invention relates to the fields of multi-source measurement data fusion and rock movement observation, and particularly relates to a water-land integrated rock movement observation method based on an unmanned ship. Background Art

[0002] Coal is the most abundant and widely distributed conventional energy source in the world and is also an important strategic resource. However, with the over-exploitation of mining areas, disasters such as ground subsidence, road cracks, and mountain collapses often occur. Therefore, timely deformation monitoring of mining areas is an important project. Especially in mining areas with a high phreatic level, it often causes groundwater seepage, arable land destruction, and house cracking, bringing huge economic losses to coal cities and also having a negative impact on the local ecological environment. In severe cases, it will threaten the safety of people's lives and property. For mining subsidence areas containing water bodies, due to the large amount of water, the traditional method of establishing a surface observation station cannot be carried out, and the safety of mining area personnel and property is always faced with a great threat.

[0003] Currently, for mining subsidence areas containing water bodies, traditional rock movement observation methods are generally used. Since the traditional methods cannot observe across water bodies, the subsidence within the water body is usually chosen to be abandoned for observation, resulting in the lack of rock movement observation data. When the mining subsidence area contains a large area of water bodies, remote sensing images are usually used to monitor the water bodies, so as to achieve the monitoring of subsidence deformation. However, this method cannot study the subsidence changes of the underwater terrain through the water body, and the monitoring data on land cannot be fused, and it is difficult to ensure the accuracy of the data. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention designs a water-land integrated rock movement observation method based on an unmanned ship.

[0005] A water-land integrated rock movement observation method based on an unmanned ship specifically includes the following steps:

[0006] Step 1: According to the rock movement parameters of the already mined coal mining face, or the rock movement parameters of the working face with similar mining data, combined with the mining data of this working face, conduct surface movement observation design of the measurement area, determine the strike observation line and the dip observation line, and ensure that the observation lines are on the main rock movement section; draw an observation line profile according to the strike observation line and the dip observation line; the mining data is the mining depth, strike length, dip length, thickness of the loose layer, and geological structure;

[0007] The strike observation line is located within the main rock movement section, and the distance D1 from the strike observation line SN to the cutting eye of this working face should be:

[0008] D 1 ≥(H 0 -h)cot(δ - Δδ)+hcotφ

[0009] In the formula, δ is the strike movement angle; Δδ is the correction value of the strike movement angle; h is the thickness of the loose layer; H 0 is the average mining depth; φ is the movement angle of the loose layer;

[0010] Among them, the length of the strike observation line SN is calculated according to the following formula:

[0011] SN = 2h cotφ + 2(H 0 -h) × cot(δ - Δδ) + l

[0012] In the formula, h is the thickness of the loose layer; H 0 is the average mining depth; l is the strike length of the working face, δ is the strike movement angle; Δδ is the correction value of the strike movement angle; φ is the movement angle of the loose layer;

[0013] The length of the dip observation line is determined on the dip main section of the subsidence basin; offset a distance d from the center of the goaf towards the down-hill direction, that is:

[0014] d = H 0 cotθ

[0015] In the formula, H 0 is the average mining depth; θ is the maximum subsidence angle;

[0016] Therefore, the length of the dip observation line EW is:

[0017] EW = 2h cotφ + (H 1 -h) cot(β - Δβ) + (H 2 -h) cot(γ - Δγ) + L 1 cosα

[0018] In the formula, L 1 is the strike length of the working face; h is the thickness of the loose layer; β, Δβ are the dip movement angle and its correction value; γ, Δγ are the up-dip movement angle and its correction value; α is the coal seam dip angle; φ is the movement angle of the loose layer; H 1 , H 2 are the mining depths of the lower boundary and the upper boundary of the mining area;

[0019] Step 2: Determine the subsidence influence range according to the strike and dip observation lengths calculated in Step 1, establish a measurement control network outside the mining subsidence range, determine the coordinates and elevations of the control points, and complete the static measurement and leveling connection measurement; use a GNSS receiver for layout, lay out the designed observation line, and complete the stone embedding work of the daily observation points on the observation line. The observation points are only laid out to the water body;

[0020] Step 3: After the working point on the observation line stabilizes, that is, it no longer continues to sink, conduct the first real-time kinematic (RTK) measurement; at the same time, use an unmanned boat to measure the land and underwater terrain around the water body; the unmanned boat is equipped with a variety of high-precision sensors such as GNSS, multibeam echosounder, 3D laser scanner, and high-precision inertial navigation to complete the acquisition of monitoring data of the land and underwater around the water body.

[0021] Step 4: Interpolate and fit the underwater data obtained by the unmanned boat to generate an underwater DEM model; interpolate the 3D laser scanning data obtained by the 3D laser scanner to generate a land DEM model; splice the land and underwater DEM models to generate a complete land-water surface DEM model and use the data measured by RTK in Step 3 to verify the accuracy of the land-water surface DEM model; if the accuracy meets the engineering requirements, complete a complete rock movement observation measurement.

[0022] Step 5: Process the observed values to obtain settlement values and conduct analysis; the settlement values consist of two parts, namely RTK settlement values and underwater land DEM settlement values; obtain the settlement values multiple times to obtain the final settlement monitoring data of the surveyed area; the observed values are the data of the land-water surface DEM model and RTK measurement.

[0023] Analyze and calculate the RTK settlement data:

[0024] Import the RTK settlement data into an Excel spreadsheet. Assume that a total of n periods of data are measured. Subtract the data of two adjacent periods to obtain the settlement value within the period; subtract the data of the first period from the last period to obtain the cumulative settlement value.

[0025] Analyze and calculate the DEM settlement values:

[0026] The DEM settlement values are obtained by raster overlay processing of multiple digital elevation models made from 3D laser scanning data and underwater sounding data, and using ArcGIS for raster data operations to obtain the settlement values of the mountaintop or other DEM extraction areas; in the raster overlay, each raster of each layer has its own pixel value. Subtract the rasters with the set width to obtain the change of each raster unit within a specific time.

[0027] Conduct multi-period observations according to the mining progress of the working face, calculate and analyze the multi-period data obtained. The processing method of the working point data on the observation line is the same as that of traditional rock movement observation data; conduct overlay analysis on the multi-period land-water DEMs obtained, compare and analyze the settlement values with the settlement values of the land RTK surveyed area. If the accuracy meets the requirements, obtain the settlement monitoring data of the surveyed area, which can provide strong technical support for the subsequent mining and settlement monitoring work in the mining area.

[0028] Advantageous technical effects of the present invention:

[0029] Traditional monitoring methods (such as levels, GPS) cannot measure water bodies, and technologies such as airborne LiDAR and InSAR cannot obtain underwater data. A single underwater depth sounder cannot combine underwater data with onshore data, and it is difficult to ensure accuracy without data overlap. The present invention combines underwater data with onshore data to complete integrated land and water monitoring, and solves the problem of deformation monitoring of mining subsidence areas containing water bodies in mining areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of an integrated land and water rock movement observation method based on an unmanned ship according to the present invention;

[0031] Figure 2 It is a schematic diagram of the design of the theoretical observation line according to the present invention;

[0032] Figure 3 It is a cross-sectional view of the strike observation line according to the present invention;

[0033] Figure 4 It is a cross-sectional view of the dip observation line according to the present invention;

[0034] Figure 5 It is a layout diagram of the observation line of the well-to-surface comparison map according to the present invention;

[0035] Figure 6 It is the underwater data obtained by the depth sounder according to the present invention;

[0036] Figure 7 It is the onshore data obtained by the 3D laser scanner according to the present invention;

[0037] Figure 8 It is the underwater DEM model according to the present invention;

[0038] Figure 9 It is the onshore DEM model according to the present invention;

[0039] Figure 10 It is the theoretical map of overlay analysis according to the present invention;

[0040] Figure 11 It is the comparison map of the subsidence values of the overlapping points in the strike direction according to the present invention;

[0041] Figure 12 It is the comparison map of the subsidence values of the overlapping points in the dip direction according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0042] The present invention will be further described below with reference to the drawings and embodiments;

[0043] Taking the 1106 working face of a certain mine as an example, since there is a measurement control network arranged in this mine, there is no need to re-arrange it. The rock movement observation design of the 1106 working face is carried out according to the rock movement parameters of the adjacent and already complete 1101 working face. The technical solution is as followsFigure 1 as shown

[0044] The observation lines designed for the ground strata movement observation station are divided into the strike observation line (SN line) and the dip observation line (EW line), as Figure 2 shown in the schematic diagram of the observation line design. The strike observation line is along the mining width direction of the working face, with the direction being due east-west, and the direction of the strike observation line is due north-south. As attached Figure 1 shown, the observation station is designed as follows according to the strata movement parameters to be adopted:

[0045] Step 1: Based on the strata movement parameters of the already mined coal mining working face or the strata movement parameters of the working face with similar mining data, combined with the mining data of this working face, conduct the surface movement observation design of the measurement area, determine the strike observation line and the dip observation line, and ensure that the observation lines are on the main cross-section of the strata movement; draw the cross-sectional diagram of the observation lines according to the strike observation line and the dip observation line; the mining data are the mining depth, strike length, dip length, thickness of the loose layer, and geological structure;

[0046] The strike observation line is located within the main strike cross-section. On the main strike cross-sectional diagram, draw a line from the cutting eye at an angle of (δ - Δδ) and angle towards the working face advancing direction to intersect the ground surface at point O. The strike line must exceed the position of point E in the working face advancing direction. One strike observation line is arranged for the observation station, and the distance D from the observation line SN to the cutting eye 1 should be:

[0047]

[0048] In the formula, δ - strike movement angle; Δδ - correction value of the strike movement angle; h - thickness of the loose layer; H 0 - mining depth; - movement angle of the loose layer.

[0049] Therefore, the distance of the dip observation line from the stop line of coal mining should be greater than 398 m.

[0050] The specific method for setting the strike observation line: From the cutting eye towards the working face advancing direction, draw a line at an angle of (δ - Δδ) to intersect the interface between the bedrock and the loose layer at a point, and then draw a line from this intersection point at angle to intersect the ground surface at point D; point D is the point not affected by the mining in the adjacent area. At the stop line of the working face, draw a line at an angle of (δ - Δδ) towards the outside of the working face to intersect the interface between the bedrock and the loose layer at a point, and then draw a line from this intersection point at angle to intersect the ground surface at point F; as Figure 3 , the length of the strike observation line SN is calculated according to the following formula:

[0051]

[0052] In the formula, h is the thickness of the loose layer; H0 $H_{av}$ is the average mining depth; $l$ is the strike length of the working face, $\delta$ is the strike movement angle; $\Delta\delta$ is the correction value of the strike movement angle; $\varphi$ is the movement angle of the loose stratum;

[0053] Design of the dip observation line (EW line);

[0054] According to the maximum subsidence value, the maximum surface subsidence point is determined on the main strike section. Through this point, a section line is made along the ore body strike, and the plane position of the dip observation line is obtained. And the boundary points of the mining influence range are determined based on the movement angle value. A strike observation line EW is arranged along the dip of the surface rock movement observation station of the working face.

[0055] The length of the dip observation is determined on the main dip section of the subsidence basin. The specific method is as follows: From the upper and lower boundaries of the mining area, lines are drawn with ($\gamma - \Delta\gamma$) and ($\beta - \Delta\beta$) respectively to intersect with the bedrock and the loose stratum, and then from the intersection points, lines are drawn at an angle to intersect the surface at points A and B. AB is the working length of the dip observation line, as Figure 4 .

[0056] The position of the observation line EW is calculated by the following formula:

[0057] Offset a distance d from the center of the goaf towards the down-hill direction, that is:

[0058] $d = H$ 0 $\cot\theta = 38.5m$

[0059] The strike observation line should be arranged at a position 38.5m offset from the center of the working face towards the down-hill.

[0060] The length of the dip observation line EW is calculated by the following formula:

[0061]

[0062] In the formula, $L$ 1 is the strike length of the working face; $h$ is the thickness of the loose stratum; $\beta$, $\Delta\beta$ are the down-hill movement angle and its correction value; $\gamma$, $\Delta\gamma$ are the up-hill movement angle and its correction value; $\alpha$ is the coal seam dip angle; $\varphi$ is the movement angle of the loose stratum; $H$ 1 , $H$ 2 are the mining depths of the lower and upper boundaries of the mining area;

[0063] Step 2: Determine the subsidence influence range according to the strike and dip observation lengths calculated in Step 1. Establish a measurement control network outside the mining subsidence range, determine the coordinates and elevations of the control points, and complete the static measurement and leveling connection measurement; Use a GNSS receiver for lofting, arrange the designed observation line, and complete the work of embedding stones for the daily observation points on the observation line. The work points are only arranged to the water body; as Figure 5 shown.

[0064] Step 3: After the working points on the observation line become stable, i.e., they no longer continue to sink (usually reaching stability after 15 days), conduct the first real-time kinematic (RTK) measurement; meanwhile, use an unmanned boat to measure the land and underwater terrain around the water body; the unmanned boat is equipped with multiple high-precision sensors such as GNSS, multi-beam echosounder, 3D laser scanner, and high-precision inertial navigation to complete the acquisition of monitoring data for the land and underwater areas around the water body; the acquired underwater data is as Figure 6 shown, and the acquired land data is as Figure 7 shown.

[0065] Step 4: Interpolate and fit the underwater data obtained by the unmanned boat to generate an underwater DEM model, as Figure 8 shown; interpolate the 3D laser scanning data obtained by the 3D laser scanner to generate a land DEM model, as Figure 9 shown; splice the land and underwater DEM models to generate a complete land-water surface DEM model and use the data measured by RTK in Step 3 to verify the accuracy of the land-water surface DEM model; if the accuracy meets the engineering requirements, complete a complete rock movement observation measurement;

[0066] Step 5: Process the observed values to obtain settlement values and conduct analysis; the settlement values consist of two parts, namely the RTK settlement value and the underwater-land DEM settlement value; obtain the settlement values multiple times to obtain the final settlement monitoring data for the surveyed area; the observed values are the data of the land-water surface DEM model and the RTK measurement;

[0067] Analyze and calculate the RTK settlement data:

[0068] Import the RTK settlement data into an Excel spreadsheet. Assume that a total of n periods of data are measured. Subtract the data of two adjacent periods to obtain the settlement value within the period; subtract the data of the first period from the last period to obtain the cumulative settlement value;

[0069] Analyze and calculate the DEM settlement value:

[0070] The DEM settlement value is obtained by raster overlay processing of multiple digital elevation models made from 3D laser scanning data and underwater sounding data, and using ArcGIS for raster data operations to obtain the settlement value of the mountaintop or other DEM extraction areas; in the raster overlay, each raster of each layer has its own pixel value. Subtract the rasters with a set width to obtain the change of each raster cell within a specific time; the principle is as Figure 10 shown.

[0071] Multi - period observations are carried out according to the mining progress of the working face, and the multi - period data obtained are calculated and analyzed. The data of the working points on the observation line are processed in the same way as the traditional rock movement observation data. The multi - period obtained land - water DEMs are subjected to superposition analysis, and the settlement values are compared and analyzed with the settlement values of the land RTK survey area. If the accuracy meets the requirements, the subsidence monitoring data of the survey area can be obtained, providing strong technical support for the subsequent mining and settlement monitoring work in the mining area.

[0072] Since the land data obtained by the three - dimensional laser scanning system carried by the unmanned ship has a limited range, traditional RTK working point monitoring is still carried out on land. There are some overlapping areas between the two types of data, which can be used for accuracy verification. The settlement values of the working points are compared with the settlement values extracted from the DEM. There are 47 overlapping points in total this time, including 31 along the strike, and the comparison of the settlement values along the strike is as Figure 11 shown, and 16 in the dip direction, and the comparison of the settlement values in the dip direction is as Figure 12 shown. Among them, there are 38 points with an error value less than 15 cm, meeting the general engineering requirements.

Claims

1. A land - water integrated rock movement observation method based on an unmanned ship, characterized in that, it specifically includes the following steps: Step 1: According to the rock movement parameters of the already mined coal mining face, or the rock movement parameters of the working face with similar mining data, combined with the mining data of this working face, conduct surface movement observation design for the measurement area, determine the strike observation line and the dip observation line, and ensure that the observation line is on the main rock movement section; draw an observation line profile according to the strike observation line and the dip observation line; the mining data includes mining depth, strike length, dip length, thickness of loose layer and geological structure; Step 2: Determine the subsidence influence range according to the strike observation line length and dip observation line length calculated in Step 1. Establish a measurement control network outside the mining subsidence range, determine the coordinates and elevations of the control points, and complete static measurement and leveling connection measurement; use a GNSS receiver for lofting, lay out the designed observation line, and complete the work of burying stones for the daily observation points on the observation line. The work points are only laid out to the water body; Step 3: After the work points on the observation line are stable, that is, no longer continue to subside, conduct the first real - time dynamic RTK measurement; at the same time, use an unmanned ship to measure the land around the water body and the underwater terrain; the unmanned ship is equipped with a variety of high - precision sensors such as GNSS, multi - beam bathymeter, 3D laser scanner and high - precision inertial navigation to complete the acquisition of monitoring data of the land around the water body and underwater; Step 4: Interpolate and fit the underwater data obtained by the unmanned ship to generate an underwater DEM model; interpolate and process the 3D laser scanning data obtained by the 3D laser scanner to generate a land DEM model; splice the land and underwater DEM models to generate a complete land - water surface DEM model and use the data measured by RTK in Step 3 to verify the accuracy of the land - water surface DEM model; if the accuracy meets the engineering requirements, complete a complete rock movement observation measurement; Step 5: Process the observation values to obtain subsidence values and conduct analysis; the subsidence values consist of two parts, namely RTK subsidence values and underwater land DEM subsidence values; obtain the subsidence values multiple times to obtain the final subsidence monitoring data of the measurement area; the observation values are the land - water surface DEM model and the data measured by RTK; Analyze and calculate the RTK subsidence values: Import the RTK subsidence values into an Excel table. Assume that a total of n - period data are measured. Subtract the adjacent 2 - period data to obtain the subsidence value within the period; subtract the data of the first period and the last period to obtain the cumulative subsidence value; Analyze and calculate the underwater land DEM subsidence values: The underwater land DEM subsidence value is obtained by raster overlay processing of multi - period digital elevation models made from 3D laser scanning data and underwater bathymeter data, and raster data operations are carried out using ArcGIS to obtain the subsidence value of the mountain top or other DEM extraction areas; in the raster overlay, each raster of each layer has its own pixel value. Subtract the rasters with the set width, and what is obtained is the change of each raster unit within a specific time.

2. The land - water integrated rock movement observation method based on an unmanned ship according to claim 1, characterized in that, Step 1 is specifically: The strike observation line is located within the main section of rock movement. The distance D1 from the strike observation line SN to the cutting roadway of this working face should be: D 1 ≥(H 0 -h)cot(δ - Δδ)+hcotφ Wherein, δ is the strike movement angle; Δδ is the correction value of the strike movement angle; h is the thickness of the loose layer; H 0 is the average mining depth; φ is the movement angle of the loose layer; Among them, the length of the strike observation line SN is calculated according to the following formula: SN = 2h cot φ + 2(H 0 - h) × cot(δ - Δδ) + l where h is the thickness of the loose layer; H 0 is the average mining depth; l is the strike length of the working face, δ is the strike movement angle; Δδ is the correction value of the strike movement angle; φ is the movement angle of the loose layer; The length of the dip observation line is determined on the main dip section of the subsidence basin; it is offset by a distance d from the center of the goaf towards the down - hill direction, that is: d = H 0 cot θ where H 0 is the average mining depth; θ is the maximum subsidence angle; Therefore, the length of the dip observation line EW is: EW = 2h cot φ+(H 1 - h) cot(β - Δβ)+(H 2 - h) cot(γ - Δγ)+L 1 cos α Where, L 1 is the strike length of the working face; h is the thickness of the loose layer; β and Δβ are the dip angle of the downhill and its correction value; γ and Δγ are the dip angle of the uphill and its correction value; α is the dip angle of the coal seam; φ is the dip angle of the loose layer movement; H 1 , H 2 are the mining depths of the lower and upper boundaries of the mining area.

3. A method for integrated land - water rock movement observation based on an unmanned ship according to claim 1, characterized in that Step 5 further includes: Conduct multi - period observations according to the mining progress of the working face, calculate and analyze the multi - period data obtained. The data processing method for the working points on the observation line is the same as that of traditional rock movement observation data; perform superposition analysis on the multi - period obtained land - water DEMs, compare and analyze the settlement values with those of the land RTK survey area. If the accuracy meets the requirements, the subsidence monitoring data of the survey area can be obtained, providing strong technical support for the subsequent mining and subsidence monitoring work in the mining area.

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