CN119439310A

CN119439310A - A method and system for detecting underground water veins in landslide sites by combining high-density electrical method and shallow low-temperature method

Info

Publication number: CN119439310A
Application number: CN202411701547.4A
Authority: CN
Inventors: 刘琨
Original assignee: Earthquake Administration Of Gansu Province
Current assignee: Earthquake Administration Of Gansu Province
Priority date: 2024-11-26
Filing date: 2024-11-26
Publication date: 2025-02-14

Abstract

The invention relates to a landslide field underground water pulse detection method and system combining a high-density electrical method and a shallow low-temperature method, comprising the steps of arranging a transmitting source, arranging a transmitting electrode distance and a plurality of measuring lines on the landslide field, and transmitting a high-density pseudo-random multi-frequency current signal; the method comprises the steps of receiving electromagnetic signals converted from pseudo-random multi-frequency current signals along a measuring line by an unmanned aerial vehicle carrying a magnetic receiver, simultaneously carrying a positioner to record position information, obtaining apparent resistivity of a landslide field according to the electromagnetic signals, obtaining a ground water pulse position of the landslide field through the apparent resistivity of the landslide field combined with the position information, setting a plurality of shallow drill points with different depths at the ground water pulse position, setting a heat source in the shallow drill points, determining the flow velocity of ground water according to the change of the temperature of the heat source along with time, and obtaining a ground water detection result. The invention is not limited by the terrain and geological conditions, improves the detection accuracy and efficiency, and can be used for detecting the underground water pulse of landslide sites.

Description

Landslide field underground water pulse detection method and system combining high-density electrical method and shallow low-temperature method

Technical Field

The invention relates to the technical field of underground water pulse detection, in particular to a landslide field underground water pulse detection method and system combining a high-density electric method and a shallow low-temperature method.

Background

In landslide hazard control, accurately detecting a groundwater vein is important for evaluating landslide stability and formulating control measures. The current common underground water pulse detection comprises a natural electric field method, a charging method, an induced polarization method (TDIP, PIP, SIP), a ground penetrating radar method (GPR) and a ground nuclear magnetic resonance method (SNMR). The above detection method has the following disadvantages:

Natural electric field methods and charging methods are limited to terrain and geological conditions.

The induced polarization method (TDIP, PIP, SIP) may require complex data processing and analysis.

Ground Penetrating Radar (GPR) is capable of providing high resolution images of subsurface structures, but has limited ability to detect deep groundwater.

The surface nuclear magnetic resonance method (SNMR is high in cost and high in technical requirements for operators).

Therefore, there is a need for a landslide field underground water vein detection method and system combining a high-density electrical method and a shallow low-temperature method, which improves detection accuracy and efficiency, and is not limited by terrain and geological conditions.

Disclosure of Invention

The invention provides a landslide field underground water pulse detection method and system combining a high-density electrical method and a shallow low-temperature method, which are not limited by terrain and geological conditions, and improve the detection accuracy and efficiency.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

In one aspect, the invention provides a landslide field underground water vein detection method combining a high-density electrical method and a shallow low-temperature method, which comprises the following steps:

Step 1, setting a transmitting source on a landslide field, arranging a transmitting pole distance and a plurality of measuring lines, and transmitting a high-density pseudo-random multi-frequency current signal;

Step 2, receiving electromagnetic signals converted from pseudo-random multi-frequency current signals along the measuring lines by adopting an unmanned aerial vehicle carrying magnetic receiver, and simultaneously carrying a positioner to record position information, and acquiring apparent resistivity of the landslide field according to the electromagnetic signals;

Step 3, obtaining the position of the underground water vein of the landslide field through the apparent resistivity of the landslide field combined with the position information;

and 4, setting a plurality of shallow drilling points with different depths at the position of the underground water vein, setting a heat source in the shallow drilling points, determining the flow rate of the underground water according to the change of the temperature of the heat source along with time, and obtaining an underground water detection result.

Optionally, the high-density pseudo-random multi-frequency current signal in the step 1 specifically comprises pseudo-random multi-frequency current signals of 7-19 main frequency points.

Optionally, the step 2 specifically includes:

Step 2.1, an unmanned aerial vehicle is adopted to carry a magnetic receiver to receive electromagnetic signals converted from the pseudo-random multi-frequency current signals along the measuring line, a positioning device is carried to record position information, the magnetic receiver is utilized to record potential difference between two measuring electrodes, the distance between the measuring electrodes is recorded, the ratio of the potential difference to the distance between the measuring electrodes is utilized to obtain single-frequency electromagnetic components, and the multi-frequency electromagnetic components of measuring points in the measuring line are recorded through electromagnetic signals with different frequencies;

step 2.2, combining adjacent frequency points by utilizing the electromagnetic components of the multiple frequency points, and calculating the derivative of the electromagnetic field of the corresponding frequency point combination on the frequency points by adopting an approximation method of first-order differential derivation;

And 2.3, converting the apparent resistivity by utilizing the derivative to obtain the apparent resistivity of the landslide field.

Optionally, the apparent resistivity of the landslide field is obtained as follows:

Wherein mu is magnetic permeability, r is distance between dipole moment center and observation point, omega is angular frequency, i is emission current, dl is length of dipole emission source, Representing the partial derivative, ex represents the component of the electric field in the x-direction, ρ _i represents the i-th frequency point apparent resistivity.

Optionally, the step 3 specifically includes:

Step 3.1, obtaining the topographic information of the landslide field, carrying out three-dimensional grid division on the landslide field based on the topographic information, combining the apparent resistivity by combining the position information, and obtaining the resistivity in each grid;

And 3.2, inverting through the resistivity in each grid to obtain the position of the underground water vein of the landslide field.

Optionally, obtaining the resistivity within each grid includes:

and acquiring the resistivity in each grid by adopting a smooth constraint least square inversion algorithm, wherein the resistivity inversion objective function is as follows:

(G^TG+λC^T C)Δm＝G^TΔd

wherein Δd is a residual vector between observed data d and forward theoretical calculation value d, G is a coefficient matrix, Δm is a modified vector of initial model m, C is a model smoothing matrix, and λ is a smoothing damping factor.

Optionally, the step 4 specifically includes:

step 4.1, after the heat source is electrified to generate heat, recording the change data of the temperature detected by each temperature probe along with time;

Step 4.2, according to the relation between the temperature value detected by the temperature probes and time, determining the vector corresponding to each probe by taking the temperature detected by each temperature probe at the same time as the vector magnitude and taking the direction from the linear heat source to each probe as the vector direction;

And 4.3, determining the direction obtained after the superposition of the vectors as the flowing direction of the groundwater according to the vector superposition principle, calculating the flowing speed of the groundwater according to the relation between the temperature change detected by each probe and the time, and synthesizing the flow speed value obtained by each probe to determine the flow speed of the groundwater.

On the other hand, in order to achieve the above purpose, the present invention also provides a landslide field underground water vein detection system combining a high-density electrical method and a shallow low-temperature method, comprising:

The signal transmitting unit is used for arranging a transmitting source on a landslide field, arranging a transmitting pole distance and a plurality of measuring lines and transmitting a high-density pseudo-random multi-frequency current signal;

The signal receiving unit is used for carrying a magnetic receiver on the unmanned aerial vehicle to receive electromagnetic signals converted from the pseudo-random multi-frequency current signals along the measuring line, and simultaneously carrying a locator to record position information;

The position detection unit is used for acquiring apparent resistivity of the landslide field according to the electromagnetic signals, and acquiring the position of the underground water vein of the landslide field by combining the apparent resistivity of the landslide field with the position information;

the flow velocity detection unit is used for setting a plurality of shallow drilling points with different depths at the position of the underground water vein, setting a heat source in the shallow drilling points, determining the flow velocity of the underground water according to the change of the temperature of the heat source along with time, and obtaining an underground water detection result.

The beneficial effects of the invention are as follows:

According to the invention, the underground water pulse of the landslide field is detected by combining a high-density electrical method and a shallow low-temperature method, an unmanned aerial vehicle is used for carrying a magnetic receiver to receive electromagnetic signals converted from the pseudo-random multi-frequency current signals along a measuring line, the apparent resistivity of the landslide field is obtained, the position of the underground water pulse of the landslide field is obtained by combining the apparent resistivity of the landslide field with the position information, the flow velocity of the underground water is further determined based on the change of the temperature of a heat source along with time, the underground water detection result is obtained, and the accuracy and efficiency of the underground water pulse detection are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a landslide field underground water pulse detection method combining a high-density electrical method and a shallow low-temperature method according to an embodiment of the invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.

High density electrical methods are an effective technique in groundwater detection by measuring the resistivity of subsurface formations by feeding direct current into the subsurface to infer groundwater distribution. The following are some key points for the application of high density electrical methods in groundwater exploration:

The basic principle of the high-density electrical method is that the high-density electrical method utilizes direct current to be conducted into the underground to measure the resistivity of the underground stratum, and the interface of different substances is judged according to the resistivity, and the measured result is the section of the earth resistivity.

The method is applied to underground water detection, and is commonly used for searching underground water resources, exploring underground caves, seawater invasion, landslide investigation, dam, reservoir and embankment leakage, karst collapse, goaf investigation and the like.

In case study, in black square areas, the loess landslide problem caused by agricultural irrigation is used for detecting the distribution rule of groundwater in the loess layer by a high-density electric method. The research result shows that the mineralization degree of the groundwater in the region is high and mainly derived from agricultural irrigation, the groundwater level in the yellow soil layer in the tableland is relatively gentle, the water level at the edge of the tableland suddenly drops, and the trend is basically consistent with landslide topography.

Compared with drilling data, in the research of the black square platform area, the detection result of the high-density electric method is basically consistent with the drilling data result, and the reliability of the high-density electric method for detecting the underground water level is proved.

In other areas, the method is used for finding out high-quality water supply sources in the urban harbor prevention area, and the result shows that the buried depth, thickness and space distribution form of the groundwater aquifer in the area can be accurately obtained.

The high-density electrical method is also used for urban groundwater and soil organic pollution investigation, and high-resistance abnormal areas are found through investigation, and are pollution halos influenced by high-concentration organic pollutants.

Shallow low temperature method groundwater detection, also known as shallow geodetic method, is a technique that utilizes the effect of groundwater flow on formation temperature to detect groundwater distribution. The following are some key information about shallow cryogenic groundwater detection:

The principle is that the shallow layer geothermometry is based on the influence of flowing underground water pulse on normal stratum temperature, shallow layer drilling holes with certain depth and density are distributed in a investigation region, the geothermic temperature of each point at the depth is measured by adopting a high-precision thermometer, and an isothermal diagram is drawn, so that the path distribution of the flowing underground water pulse is inverted.

The method has the advantages of high speed, high efficiency, low cost, simple and easy operation and small influence of terrains, and can conveniently obtain the information of the spatial distribution, the reserve and the like of the underground water vein.

The application field is that the shallow layer geotherm measurement method is widely applied in the fields of landslide groundwater distribution, reservoir dam bottom leakage and the like.

The depth of measurement is 1 meter deep, the borehole is shallow in measurement of the ground temperature, the influence of daily variation is small, and the application is wide.

The detection condition is that experiments prove that when the temperature difference between the underground water and the normal stratum is more than 2.5 ℃, the method can be used for detecting the information such as the spatial distribution, the accumulation and the like of the underground waterway.

And (3) correcting the result, namely, the result is required to be corrected and can be used for analysis because the shallow ground temperature can be influenced by the annual ground temperature, micro-topography, geology and other factors.

The case application is that in a typical collapse post erosion area of Wuhua county in Guangdong, a shallow layer ground temperature method is applied to explore the underground water distribution, and the effect of the underground water on the collapse post erosion is discussed from the perspective of hydraulic erosion.

And (3) analyzing the result, namely correcting the result of all the measuring points to obtain a maximum temperature difference of 6.8 ℃, and obtaining a temperature difference between the average water temperature of the spring points and the normal stratum of 7.2 ℃, so that the experimental area is suitable for a shallow geothermal measurement method. The change of the temperature field in the field can be intuitively reflected through the isotherm diagram, and the position with dense isotherm distribution, namely the position with intense temperature field change, reaches the extreme value, so that the groundwater vein flow path is deduced.

In summary, the high-density electrical method and the shallow low-temperature method are effective technologies for detecting groundwater, can detect groundwater resources with lower cost and higher efficiency, and have important significance for water resource management and environmental investigation.

The following embodiments are also applicable to other detection methods, and the detection is described by taking the above method as an example, in which the technique for visualizing the groundwater vein in a planar and 2-dimensional manner in relation to the groundwater vein in a specific land area and the detection and confirmation system of groundwater in the groundwater vein of the present invention is a 4-dimensional water circulation reproduction, analysis, prediction, visualization simulation system using a computer for reproducing, analyzing, predicting, visualizing the water circulation condition from the past to the future in a certain range of land such as the country, and the like, and is realized by the following structure:

The method comprises storing satellite image data and local actual measurement data and existing published topography and geological data or arbitrary data in the satellite image data or the local actual measurement data and the existing published topography and geological data in a storage part, performing simulation based on surface and subsurface 3-dimensional topography and geological models in a certain range of land, which are generated by the satellite image data or the existing published topography and geological data, by executing a simulation program prepared based on the definition of an analysis problem for solving a requested water problem, performing an initialization process for setting the subsurface of the 3-dimensional topography and geological model to a saturated zone, generating an initialization model, performing a simulation process based on the execution of the simulation program for the initialization model, performing a simulation process based on the operation process performed by an operation part, performing a water quality and water quantity value comparison process and the like by the image generation process performed by an image generation process part, performing a simulation process based on the simulation result from the input part, performing a simulation process based on various parameters related to weather, hydrology, topography, land utilization, human body, fluid physical property, chemical substance property, and the like for future prediction, and the like, and displaying a simulation result in a dynamic image from the future to the future, and displaying the simulation process by the simulation part, and the simulation process by the simulation process, and the simulation process being performed by the simulation part, and the dynamic image can be displayed by the dynamic image is displayed by the simulation part 2.

In addition, a technique for enabling a 3-dimensional display of the position of groundwater (or a water source) in a groundwater vein in a specific land area to be visualized in a 2-dimensional manner by drilling holes at anchor points is achieved by the following structure:

The structure comprises a plurality of electrode groups arranged in a specific land area along a measuring line, a measuring point switching unit for combining and switching 2 poles as potential electrodes among the electrodes of the 4 poles arranged in a dipole-dipole arrangement, the other 2 poles as current electrodes, performing horizontal exploration and underground vertical exploration of the specific land area by a specific resistance method and a temperature nano method, a measuring unit for applying a voltage including a high frequency and a low frequency to the potential electrodes of the 2 poles arranged in the dipole-dipole arrangement, measuring currents divided by the high frequency and the low frequency by using the current electrodes of the other 2 poles for each measuring point of the whole specific land area, a measuring point specific resistance calculating unit for calculating an impedance ratio between each measuring point and each measuring point according to a specific resistance value divided by the high frequency and the low frequency at each measuring point, and calculating an impedance ratio between each measuring point and each measuring point according to a specific resistance value of each measuring point, wherein the impedance ratio between each measuring point and each measuring point is calculated according to a specific resistance value of each measuring point, and the ratio between each measuring point and each measured point is calculated according to a specific resistance value of each measured point.

Only the detection method description is provided below:

S1, designing a high-density earthquake and electric method combined observation system according to the stope space conditions and the goaf geological detection tasks of the strip mine, and determining high-density earthquake and electric method combined observation system parameters according to the stope space conditions and the geological detection tasks so as to realize full-coverage effective detection of target detection depth. The high-density earthquake and electric method combined observation system comprises an earthquake and electric method combined detection line which is arranged in a detection working area, an earthquake electric instrument which is arranged in the detection working area, an electric method long-row electrode system which is arranged on the combined detection line, a power supply station and an earthquake focus and a wave detector which are arranged on the combined detection line. The earthquake offset distance is not less than 20m, the number of the geophone channels is not less than 12 channels, the number of times of repeated covering is not less than 6 times, the power supply station is arranged according to the length of the electrode arrangement, one power supply station is additionally arranged on each 60-meter long electrode wire, and the distance between the geophone channels is 1-2 m as the distance between the geophone channels. The method comprises the steps of S2, collecting seismic data and electrical method data by utilizing a high-density seismic and electrical method combined observation system, processing the collected seismic data and electrical method data to obtain a seismic section and an electrical method detection section, collecting the seismic and electrical method data by utilizing the high-density seismic and electrical method combined observation system, generating effective reflected waves with enough energy required by seismic source excitation, enriching high-frequency signals, suppressing noise by adopting a multiple enhancement method when an artificial mechanical seismic source is used, and storing and recording acquired signals by a quality judgment qualifier, wherein an electrical method power supply has enough power, the power supply voltage and current can be moderately adjusted according to the depth of a detection target layer.

S2, the process of processing the acquired seismic data and the electrical method data specifically comprises the steps of preprocessing the seismic data, gather, static correction, speed analysis, dynamic correction, superposition and prestack migration, wherein the migration method adopts Kirchhoff integral method prestack migration, distortion multipoint smoothing, smoothing and filtering of the electrical method data and resistivity tomography, and the seismic profile and the electrical method profile are obtained after processing. The migration method comprises the steps of pre-stacking migration through a Kirchhoff integration method, obtaining a seismic profile of a detected line after processing, showing the seismic profile of the detected line after processing data, carrying out contrast analysis on a reflection wave group on the detected line, judging effective signals by combining existing geological data of a detection area, tracking the same phase axes of different wave groups, analyzing and finely analyzing and detecting a front geological abnormal body by utilizing the continuity, amplitude and phase change and spatial spread form of the same phase axes of the wave groups, comprehensively analyzing and detecting a front geological condition, specifically, carrying out migration processing in data processing by using the Kirchhoff integration method, and carrying out processing on high-density electrical method data, wherein the processing steps comprise distortion multipoint smoothing, filtering and resistivity inversion imaging of the electrical method data, and obtaining the high-density electrical method detection profile after processing.

S3, extracting seismic attribute data of the obtained seismic section, then carrying out optimization analysis on the extracted seismic attribute data, fusing the optimized seismic attribute data sensitive to the goaf with electrical resistivity data sensitive to the water content to form an attribute fused seismic and electrical attribute section, carrying out horizon calibration and tracking on a target layer of the attribute section, and analyzing the occult goaf space occurrence form and the water content under detection. And S3, extracting goaf-sensitive seismic attribute data of the obtained seismic section, wherein the goaf-sensitive seismic attribute data comprises various seismic attributes related to amplitude, phase and frequency, and the extracted multi-seismic attribute data is optimized to obtain goaf-structure and water-sensitive seismic attribute data and electrical attribute data. And S3, fusing seismic attribute data sensitive to the goaf with electrical resistivity data sensitive to the water content, wherein the data fusion specifically comprises the steps of normalizing different attribute data, solving correlation coefficients, calculating characteristic values and characteristic vectors, converting fusion attributes and calculating the contribution rate of the fusion attributes, and selecting an attribute value with the highest contribution rate of the fusion attributes as fused data to form a section. And S3, performing horizon calibration and tracking on the target layer of the attribute profile, namely performing horizon calibration on the drill hole and the logging data thereof according to the detection zone goaf exploration verification, performing target horizon tracking analysis by combining the two profile data, analyzing the space occurrence state of the hidden goaf by utilizing the continuity, amplitude and phase changes and the space spread of the phase axis of the seismic wave group, and judging the goaf water content by utilizing the electrical resistivity characteristics. Specifically, the sensitive seismic attribute data and the electrical resistivity data are fused by adopting a main attribute analysis method. The main attribute analysis eliminates the information of the overlapped parts in the attribute variables by analyzing and processing the multi-group attribute data, and recombines the attribute variables into new variable groups with smaller number, the new variable groups obtained by recombination have the mutually uncorrelated relation between every two, and the obtained main attribute variables keep the information quantity of the original data as much as possible while removing the overlapped parts between the data. And substituting the seismic data and the electrical data into calculation through the main attribute analysis method, and obtaining the characteristic value contribution rate and the accumulated contribution rate of the main attributes A1 and A2 after main fusion and the correlation coefficient between the original data and the data after conversion into the main attributes through calculation. And selecting main attributes with high contribution rate as fused data to obtain a seismic and electrical data fusion result profile, performing horizon calibration by utilizing exploration verification drilling and logging data thereof, performing target horizon tracking analysis by combining the two profile data, analyzing the space occurrence state of a hidden goaf by utilizing the continuity, amplitude and phase changes and space spread of a seismic wave group phase axis, and judging the goaf water content by utilizing electrical resistivity characteristics.

The embodiment discloses a landslide field underground water pulse detection method combining a high-density electrical method and a shallow low-temperature method, which comprises the following steps of 1, setting a transmitting source in the landslide field, laying a transmitting polar distance and a plurality of measuring lines, transmitting high-density pseudo-random multi-frequency current signals, 2, adopting an unmanned aerial vehicle to carry a magnetic receiver to receive electromagnetic signals converted from the pseudo-random multi-frequency current signals along the measuring lines, simultaneously carrying a positioner to record position information, acquiring apparent resistivity of the landslide field according to the electromagnetic signals, 3, acquiring the underground water pulse position of the landslide field by combining the apparent resistivity of the landslide field with the position information, 4, setting a plurality of shallow drilling points with different depths in the underground water pulse position, setting a heat source in the shallow drilling points, and determining the underground water flow velocity by the change of the temperature of the heat source along with time to acquire an underground water detection result.

Further, the step 1 specifically includes:

Selecting a transmitting source at a proper position of a landslide field, arranging transmitting polar distances A and B, setting the linear distance between the AB poles to be 1 km to 2 km, connecting the AB electrodes to an AB output port of a transmitter through cables respectively according to specific topography conditions, enabling the cables to meet the current-carrying capacity requirement of transmitting current, transmitting high-power pseudo-random multi-frequency current signals by the transmitter, enabling the current to be usually tens of amperes to hundreds of amperes, enabling transmitting waveforms to be dense frequency point pseudo-random multi-frequency waves, enabling a main frequency point to select one of 7 frequency, 9 frequency, 11 frequency, 13 frequency, 15 frequency and 19 frequency according to actual conditions, measuring and recording transmitting current information, setting a plurality of measuring lines in a target detecting area according to detecting tasks, enabling the distance between the measuring lines to be 50 meters to 100 meters, and planning a flight task plan according to a certain principle.

Further, step 2 specifically includes:

step 2.1, recording potential difference between two measuring electrodes by utilizing a magnetic receiver, recording distance between the measuring electrodes, acquiring electromagnetic components of a single frequency point by utilizing the ratio of the potential difference to the distance between the measuring electrodes, and recording the electromagnetic components of multiple frequency points of measuring points in a measuring line by utilizing electromagnetic signals of different frequencies;

Step 2.2, combining adjacent frequency points by utilizing electromagnetic components of multiple frequency points, and calculating the derivative of the electromagnetic field of the corresponding frequency point combination on the frequency points by adopting an approximation method of first-order differential derivation;

and 2.3, converting the apparent resistivity by using the derivative to obtain the apparent resistivity of the landslide field.

Further, the apparent resistivity of the landslide field is obtained as follows:

Further, the step 3 specifically includes:

and 3.1, obtaining the topographic information of the landslide field, carrying out three-dimensional grid division on the landslide field based on the topographic information, combining the apparent resistivity by combining the position information, and obtaining the resistivity in each grid.

Further, obtaining the resistivity within each grid includes:

(G^TG+λC^T C)Δm＝G^TΔd

Further, step 4 specifically includes:

More specifically, the principle of step 4.1 is:

The central position of one end of the probe is provided with a long straight resistance wire with the resistance value of 20 ohms, two ends of the resistance wire are connected with a 25 volt voltage-stabilizing direct current power supply, 8 high-precision temperature sensors are arranged on the circumference with the radius of 2.5cm at equal intervals by taking the resistance wire as the center, the temperature sensors are connected with a multi-path data acquisition system through signal wires, the data acquisition system is connected with a microcomputer through data transmission wires, the microcomputer is used for controlling a power supply switch of the resistance wire, after the power supply is started, the multi-path data acquisition system is controlled to detect the temperature value of each temperature sensor once every certain time, meanwhile, the acquired temperature data are transmitted to the microcomputer, and the data are automatically stored by control software.

The embodiment also provides a landslide field underground water pulse detection system combining a high-density electrical method and a shallow low-temperature method, which comprises the following steps:

the signal receiving unit is used for receiving electromagnetic signals converted from pseudo-random multi-frequency current signals along the measuring line by adopting the magnetic receiver carried by the unmanned aerial vehicle, and simultaneously carrying the locator to record position information;

the flow velocity detection unit is used for setting a plurality of shallow drilling points with different depths at the position of the underground water vein, setting a heat source in the shallow drilling points, determining the flow velocity of the underground water according to the change of the temperature of the heat source along with time and obtaining the detection result of the underground water.

The above embodiments are merely illustrative of the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, but various modifications and improvements made by those skilled in the art to which the present invention pertains are made without departing from the spirit of the present invention, and all modifications and improvements fall within the scope of the present invention as defined in the appended claims.

Claims

1. A method for detecting underground water veins in a landslide site by combining a high-density electrical method and a shallow low-temperature method, characterized in that it comprises:

Step 1, setting up a transmitting source at the landslide site, laying out transmitting pole distances and multiple measuring lines, and transmitting a high-density pseudo-random multi-frequency current signal;

Step 2, using a drone equipped with a magnetic receiver to receive electromagnetic signals converted from pseudo-random multi-frequency current signals along the survey line, and carrying a locator to record position information, and obtaining the apparent resistivity of the landslide site according to the electromagnetic signals;

Step 3, obtaining the location of the groundwater vein of the landslide site by combining the apparent resistivity of the landslide site with the location information;

Step 4, setting a plurality of shallow drilling points of different depths at the location of the groundwater vein, setting a heat source in the shallow drilling point, determining the groundwater flow rate by the change of the temperature of the heat source over time, and obtaining the groundwater detection result.

2. The method for detecting underground water veins in landslide sites by combining high-density electrical method and shallow low-temperature method according to claim 1 is characterized in that the high-density pseudo-random multi-frequency current signal in step 1 specifically includes: a pseudo-random multi-frequency current signal with 7-19 main frequency points.

3. The method for detecting underground water veins in landslide sites by combining high-density electrical method and shallow low-temperature method according to claim 1, characterized in that said step 2 specifically comprises:

Step 2.1, using a drone equipped with a magnetic receiver to receive the electromagnetic signal converted from the pseudo-random multi-frequency current signal along the measuring line, and carrying a locator to record position information, using the magnetic receiver to record the potential difference between two measuring electrodes, and at the same time recording the distance between the measuring electrodes, using the ratio of the potential difference to the distance between the measuring electrodes to obtain a single frequency electromagnetic component, and recording the multi-frequency electromagnetic components of the measuring points in the measuring line through electromagnetic signals of different frequencies;

Step 2.2, using the multi-frequency electromagnetic components to combine adjacent frequency points, and using an approximate method of first-order difference derivation to calculate the derivative of the electromagnetic field of the corresponding frequency point combination with respect to the frequency point;

Step 2.3, using the derivative to convert the apparent resistivity to obtain the apparent resistivity of the landslide site.

4. The method for detecting underground water veins in a landslide site by combining high-density electrical method and shallow low-temperature method according to claim 3 is characterized in that the apparent resistivity of the landslide site is obtained as follows:

Among them, μ is the magnetic permeability, r is the distance between the center of the dipole moment and the observation point, ω is the angular frequency, i is the emission current, dl is the length of the dipole emission source, represents the partial derivative, Ex represents the component of the electric field in the x direction, and ρ _i represents the apparent resistivity at the i-th frequency point.

5. The method for detecting underground water veins in landslide sites by combining high-density electrical method and shallow low-temperature method according to claim 1, characterized in that obtaining the step 3 specifically comprises:

Step 3.1, obtaining the terrain information of the landslide site, dividing the landslide site into three-dimensional grids based on the terrain information, and combining the apparent resistivity with the location information to obtain the resistivity in each grid;

Step 3.2, obtaining the location of the groundwater veins at the landslide site by inverting the resistivity within each grid.

6. The method for detecting underground water veins in landslide sites by combining high-density electrical method and shallow low-temperature method according to claim 5, characterized in that obtaining the resistivity in each grid comprises:

The smooth constrained least squares inversion algorithm is used to obtain the resistivity in each grid. The resistivity inversion objective function is:

(G ^T G + λ C ^T C) Δm = G ^T Δd

Among them, Δd is the residual vector between the observed data d and the forward theoretical calculated value d; G is the coefficient matrix; Δm is the modification vector of the initial model m, C is the model smoothing matrix; λ is the smoothing damping factor.

7. The method for detecting underground water veins in landslide sites by combining high-density electrical method and shallow low-temperature method according to claim 1, characterized in that step 4 specifically comprises:

Step 4.1, after the heat source is powered on and generates heat, record the temperature change data detected by each temperature probe over time;

Step 4.2, according to the relationship between the temperature value detected by the temperature probe and time, the temperature detected by each temperature probe at the same time is taken as the vector magnitude, and the direction from the linear heat source to each probe is taken as the vector direction, to determine the vector corresponding to each probe;

Step 4.3, according to the principle of vector superposition, the direction obtained after superposition of each vector is determined as the groundwater flow direction. According to the relationship between the temperature change detected by each probe and time, the groundwater flow velocity is calculated. The groundwater flow velocity is determined by combining the flow velocity values obtained by each probe.

8. A landslide site groundwater vein detection system combining high-density electrical method and shallow low-temperature method, characterized by comprising:

The signal transmitting unit sets a transmitting source at the landslide site, arranges transmitting pole distances and multiple measuring lines, and transmits high-density pseudo-random multi-frequency current signals;

A signal receiving unit, using a drone equipped with a magnetic receiver to receive the electromagnetic signal converted from the pseudo-random multi-frequency current signal along the measuring line, and carrying a locator to record position information;

A position detection unit, which obtains the apparent resistivity of the landslide site according to the electromagnetic signal, and obtains the position of the underground water vein of the landslide site by combining the apparent resistivity of the landslide site with the position information;

The flow velocity detection unit sets a plurality of shallow drilling points of different depths at the location of the groundwater vein, sets a heat source in the shallow drilling point, determines the groundwater flow velocity by the change of the temperature of the heat source over time, and obtains the groundwater detection result.