A slope fissure parameter in-situ testing system and method based on resistivity method

Abstract

The application provides a kind of in-situ test system and method of slope fissure parameter based on resistivity method, wherein the specific process of test method is, first, obtain slope geological exploration data and slope design parameter, determine the length of three main fissure measuring line, electrode rod spacing and isolation coefficient, calculate the detection depth;Into conductive hydrogel in slope surface fissure, arrange measuring line, install electrode rod;Obtain underground longitudinal section resistivity distribution map, determine fissure depth;Insert electrode rod into slope body to the maximum depth of fissure, fix electrode, measure slope surface fissure parameter;Move electrode to different horizon, measure each layer fissure parameter;Import fissure parameter and depth into computer modeling to determine the whole slope body fissure rate.The application can quickly and accurately measure slope surface and internal fissure parameter, and the method has the characteristics of environmental protection and energy saving, and the injected hydrogel can also play the role of reinforcing the development of fissure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geotechnical engineering, and particularly relates to a slope fissure parameter in-situ testing system and method based on a resistivity method. BACKGROUND

[0002] With the continuous development of public infrastructure such as railways, highways, hydropower, waterways and ports, a large number of artificial soil slopes are inevitably generated. These soil slopes are prone to form dry shrinkage fissures under the action of atmospheric dry-wet cycles. The formation of fissures directly reduces the shear strength of the soil on the one hand, and on the other hand, can act as a dominant seepage channel to speed up the rainfall infiltration during rainfall, thereby seriously affecting the slope stability and ultimately causing slope collapse and landslide and other shallow instability disasters. Therefore, it is of great significance to measure the fissure parameters of the slope in the field.

[0003] The existing mature technology can easily obtain the surface fissure parameters of the soil slope, but it is insufficient to reflect the fissure conditions inside the soil. The existing body fissure testing methods can be divided into two categories: indoor testing methods and outdoor testing methods. The indoor testing methods mainly include CT testing method and grouting method, etc. Although the CT testing method can realize real-time, continuous and non-destructive detection of the measured soil sample with high resolution, it has the disadvantages of complex operation, high cost, harmful to human body during the test process and the need for special equipment, which limits its application in the testing of slope fissure parameters. The grouting method is to pour a flowing material (such as resin, gypsum, paraffin, etc.) into the fissure, and after the flowing material solidifies, the soil body is excavated, and the fissure shape and parameters are obtained by directly measuring the parameters of the solidified material. Although this method can better test the parameters of the fissure, it will cause irreversible damage to the slope soil body. The outdoor testing methods mainly include drilling method, digital photography fissure testing method and ultrasonic wave method, etc. The drilling method will change the original structure of the slope fissure when drilling, resulting in errors in the fissure parameters, and the construction will damage the integrity of the slope. The digital photography fissure testing method is mainly used for surface fissure parameter measurement, and its accuracy is greatly affected by the instrument equipment, light environment interference and human factors, especially when there is plant coverage on the slope surface, the application is more difficult. The ultrasonic wave method is mainly applied to homogeneous soil, and the soil containing impurities is easy to cause the dispersion of the sound wave velocity, thereby leading to the distortion of the fissure test results. SUMMARY

[0004] The purpose of the embodiment of the present application is to provide a slope fissure parameter in-situ testing system and method based on a resistivity method, to overcome the limitations of the prior art in the detection of internal fissures of the soil slope, such as complex operation, high cost, destructive and great influence of environmental factors, and to provide an efficient and non-destructive fissure parameter in-situ measurement solution.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is a kind of in-situ test system of slope fissure parameter based on resistivity method, including high-density resistivity method host arranged on ground, one end of the high-density resistivity method host is connected with electric energy conversion device through cable, the other end is connected with multi-channel electrode conversion device;The other end of the electric energy conversion device is connected with small wind turbine through cable;The multi-channel electrode conversion device is connected with electrode rod through cable and probe;

[0006] Electrode rod, the electrode rod is inserted into the slope to be measured, and a plurality of probes are included on the electrode rod;

[0007] Electrode, for measuring voltage, the electrode is realized by being fixed on different probes to measure different depths;

[0008] The probe is specifically a movable conductive probe, which is used to adjust the measurement depth and realize the conduction between the electrode and the multi-channel electrode conversion device.

[0009] A kind of in-situ test method of slope fissure parameter based on resistivity method, comprising the following steps:

[0010] S1, field survey selects three highest development degree fissures on slope surface, and injects conductive hydrogel into these fissures;

[0011] S2, the total length L of the measuring line of the three fissures obtained in S1, electrode rod spacing X, isolation coefficient n are determined, and the detection depth D=nX is calculated;

[0012] S3, according to the data determined in S2, electrode rod is arranged with spacing X, and electrode rod is connected through cable, to construct a vertical electrode network, the electrode network is then connected in series with cable through a multi-channel electrode conversion device, to be connected to high-density resistivity method host, so that high-density resistivity method host can collect each electrode rod data;

[0013] The electrode network is placed at the midpoint of the width direction of the fissure horizontal plane;

[0014] S4, the electrode rod for power supply and the electrode rod for measurement in the measurement process are determined, the voltage data collected by each electrode rod is converted into resistivity data by high-density resistivity method host, the apparent resistivity of each measurement point position is determined, and the apparent resistivity is calculated by two-dimensional inversion, to obtain the high-density resistivity apparent resistivity section distribution graph of the three fissures along the depth direction, finally, the depths h1, h2 and h3 of the three fissures are determined, and the maximum value among the three is taken as the depth of the deepest fissure developed on the slope surface, and is recorded as h max ;

[0015] S5, inject conductive hydrogel into all the cracks on the slope surface until it is flush with the slope surface, divide the slope surface into multiple rectangles according to 1 / 10-1 / 5 of the length and width of the slope, insert electrode rods at the corners of the rectangles, redistribute the electrode rods, and insert the electrode rods to a depth of h max ; move the electrodes on all the electrode rods to the probes at the same height as the slope surface and fix them, and detect and measure the crack parameters of the slope surface;

[0016] S6, measure the crack parameters of each layer and the bulk crack rate of the slope.

[0017] Further, the electrode rod spacing X in S2 is between 1 / 10-1 / 15 L.

[0018] Further, the determination process of the apparent resistivity section distribution map in S4 high-density resistivity method is as follows:

[0019] S401, set the spacing between the electrode rods as X, select the first and fourth electrode rods as the power supply electrode rods A and B, and the second and third electrode rods as the measurement electrode rods M and N for measurement; mark the underground resistivity characteristics at the midpoint between the two points MN and at a depth of X as point a;

[0020] S402, keep the spacing between the electrode rods as X, select the second and fifth electrode rods as the power supply electrode rods A and B, and the third and fourth electrode rods as the measurement electrode rods M and N for measurement; mark the underground resistivity characteristics at the midpoint between the two points MN and at a depth of X as point b; repeat the processes of S401-S402 until the measurement of all the measurement points in the ab line is completed;

[0021] S403, set the spacing between the electrode rods as 2X, select the first and seventh electrode rods as the power supply electrode rods A and B, and the third and fifth electrode rods as the measurement electrode rods M and N for measurement; mark the underground resistivity characteristics at the midpoint between the two points MN and at a depth of 2X as point c; repeat the process of S403 until the measurement of all the measurement points in the c line is completed;

[0022] S404, set the spacing between the electrode rods as 3X and 4X, respectively, and measure according to the method of S403, process the measured data through the high-density resistivity method host, and model the apparent resistivity map of the section.

[0023] Further, the crack parameter process of the S5 slope surface section is specifically: moving the electrode to the probe on the electrode rod at the slope surface position, connecting all the cable lines connected with the electrode rod to the multi-channel electrode conversion device; after measuring each rectangular test area, determining the apparent resistivity cross section of the slope surface section by the data processing of the high-density resistance method host, determining the number of cracks, the length, width and area of each crack and the specific position of the crack on the section of the slope surface section through the output result of the host, and further determining the slope surface crack rate.

[0024] Further, the specific determination method of the slope surface crack rate is:

[0025]

[0026] Wherein: ξ s is the slope surface crack rate, A i is the crack area in the i-th test area, j is the number of test areas, and A is the area of the entire area to be measured.

[0027] Further, the electrode rod in S5 is set as a group of four to form a rectangular test area, wherein the current input end is the electrode rod A and B, and the measurement electrode rod is M and N.

[0028] Further, the specific process of S6 is: dividing the electrode rod into m segments, recording the length of each segment as x, setting probes at both ends of each segment, fixing the electrode on the probe x away from the slope surface, connecting the cable line to the multi-channel electrode conversion device to start measurement; when the depth of the slope surface is x, the measurement is completed, the electrode is moved to the next probe, and the measurement is performed again until the depth is h max ; obtaining the crack parameters at the section with an integer multiple of the depth x, establishing a three-dimensional space model based on the crack parameters, and determining the bulk crack rate of the entire slope based on the three-dimensional space model.

[0029] Further, the specific determination method of the bulk crack rate is:

[0030]

[0031] Wherein: ξ v is the bulk crack rate, V i is the volume of the i-th crack, k is the number of cracks, A is the area of the entire area to be measured, and H is the test depth.

[0032] Further, the specific components of the hydrogel include: 10-12 parts by mass of agarose powder, 0.5-1.5 parts by mass of carbon nanotubes, and 18-20 parts by mass of sodium chloride.

[0033] The hydrogel is prepared by the following method: firstly, dissolving sodium chloride powder in 90-110 parts by mass of deionized water to prepare a sodium chloride solution, then mixing and stirring agarose powder and carbon nanotubes to obtain a mixed powder, and slowly adding the prepared sodium chloride solution into the mixed powder after uniform stirring.

[0034] Compared with the prior art, the beneficial effects of the present application include the following points:

[0035] 1. The method can quickly and accurately measure the surface and internal cracks of the slope, including but not limited to key parameters such as crack length, width, area, depth and crack rate. The present application not only has high precision, but also has strong operation simplicity and wide application range, and can quickly complete the test work in various environments.

[0036] 2. In order to improve the crack identification efficiency and enhance the stability of the slope, a new type of ion-conducting hydrogel material is introduced. This material has high strength, high fluidity and excellent conductivity (resistivity between 10 -2 ~ 10 -1 Ω·m), which can form a clear resistivity contrast with the surrounding medium after being injected into the slope crack, thereby facilitating the rapid positioning of the crack structure. At the same time, due to its unique physical and chemical properties, the hydrogel used in the present application can also effectively reinforce the crack area and inhibit the further expansion of the crack, playing a dual role.

[0037] 3. Considering the importance of environmental protection, the present application uses the airflow generated by passing vehicles on the highway to drive the power generation equipment, thereby obtaining stable and continuous electric energy. This self-sufficient power generation mechanism significantly reduces the demand for external energy sources, while almost no pollutants are emitted during operation.

[0038] In summary, the new technology provided by the present application overcomes many limitations of traditional methods, and provides a new solution for precise detection of internal cracks in soil slopes by combining advanced material science and renewable energy technology. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0040] Figure 1 is a flow chart of the test method of the present embodiment;

[0041] Figure 2 is a cross-sectional view of the fracture depth test of the present embodiment;

[0042] Figure 3 is a plan view of the fracture depth test of the present embodiment;

[0043] Figure 4 is a subsurface profile view of the test method of the present embodiment;

[0044] Figure 5 is a subsurface plan view of the test method of the present embodiment;

[0045] Figure 6 is an electrode distribution map of the same layer of the present embodiment;

[0046] Figure 7 is a view resistivity cross-sectional view of the fracture depth measurement by the high-density resistivity method of the present embodiment;

[0047] Figure 8 is a view resistivity cross-sectional view of the slope surface profile of the test of the present embodiment;

[0048] Figure 9 is a fracture morphology map of the present embodiment modeling the data measured by the cross-section into three-dimensional modeling software;

[0049] In the figure, 1, electrode rod; 2, electrode; 3, cable; 4, fracture after injecting conductive gel; 5, multi-channel electrode switching device; 6, high-density resistivity method host; 7, power conversion device; 8, wind turbine generator set. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0051] As Figure 1 , the present embodiment provides a slope fracture parameter in-situ test method based on resistivity method, and the specific process is as follows:

[0052] S1, field investigation survey and selection of three highest development degree fractures on the slope surface, injection of high conductivity hydrogel into these fractures. This process not only enables the hydrogel to form a closed electrical circuit with the surrounding soil, but also significantly increases the resistivity difference between the fracture interior and the surrounding soil, thereby facilitating accurate identification and analysis of the fracture area.

[0053] S2, determine the total length L of the three largest development degree of the crack line obtained by field investigation, electrode stick 1 spacing X, isolation coefficient n and calculate the detection depth D=nX.

[0054] In this embodiment, in order to ensure the balance between precision and workload, the electrode stick 1 spacing is selected between 1 / 10-1 / 15L; the isolation coefficient n needs to be adjusted according to the apparent resistivity section: n=p sum -(p a -1), p sum is the number of access electrode stick 1; p a is the number of device electrode stick, since the Wenner device is used, p a is 4, to ensure that the detection depth is greater than or equal to the depth of the crack 4 after injecting conductive gel, to ensure that the crack depth can be detected.

[0055] In some possible embodiments, in order to ensure the accuracy of modeling measurement, when considering the length of the line, the total length L of the line is about 2-3 times the electrode stick spacing X of the actual length of the crack 4 after injecting conductive gel.

[0056] S3, as Figure 2 、 Figure 3 , the crack region is prepared with corresponding electrode stick 1, the number of electrode stick 1 is determined according to the length of the line and the electrode stick spacing X, and the electrode stick 1 is arranged according to the electrode stick spacing X, and each electrode stick 1 is connected by cable 3 to form an electrode net in the vertical direction, and the electrode net is placed at the midpoint of the width direction of the crack horizontal plane; then the multi-channel electrode conversion device 5 is connected with the cable 3 in series and connected to the high-density resistivity method host 6, so that the high-density resistivity method host 6 can collect the data measured by each electrode stick 1.

[0057] S4, obtain the underground longitudinal section resistivity distribution map, and determine the crack depth

[0058] The high-density resistivity method host 6 converts the voltage data measured by the electrode stick 1 into resistivity data, determines the apparent resistivity of each measurement point position, and performs two-dimensional inversion calculation on the apparent resistivity to obtain the high-density resistivity apparent resistivity section distribution graph of the three cracks along the depth direction (such as Figure 7 ), and finally determine the depths h1, h2, h3 of the three cracks, and take the maximum value among the three as the deepest crack depth on the measured slope surface, denoted as h max .

[0059] In some specific embodiments, the high-density resistivity method host 6 analyzes and processes the data collected by the electrode stick 1 and inverts the image, which can obtain the apparent resistivity section graph of the test section (such as Figure 7). The apparent resistivity profile can clearly show the location of the fractures in the test section, and thus the depth of each fracture can be determined. The test process requires three measurements for each fracture, and the depths of the three fractures h1, h2, h3 are determined as follows:

[0060] As Figure 7 The present embodiment first determines the supply electrode rods (A and B) and the measurement electrode rods (M and N) involved in the measurement process, adjusts the positions of the electrode rods 1, and records the resistivity data at different positions to construct an image of the underground structure.

[0061] S401, first determine the electrode rod spacing X, and arrange the electrode rods 1 on the ground according to the spacing X. The electrode rods A and B are supply electrode rods for injecting current into the ground, and the electrode rods M and N are measurement electrode rods for measuring the voltage difference generated by the current.

[0062] S402, set the isolation coefficient to n = 1, i.e. the actual distance between the electrode rods 1 is equal to the basic spacing X. At this time, the first electrode rod is selected as A, the second as M, the third as N, and the fourth as B (as shown in Figure 7 the middle position of A, M, N, and B). The measurement result represents the underground resistivity characteristics at the midpoint between the points M and N, with a depth of about nX, marked as point a.

[0063] S403, keep n unchanged, and in turn use the next group of electrode rods 1 as new A, M, N, and B electrode rods, i.e. use the second electrode rod as the new A electrode rod, and the third to fifth electrode rods as M, N, and B electrode rods, respectively, to obtain the data of point b. Repeat this process until all the measurement points in row ab are completed.

[0064] S404, after completing a round of measurement, increase the isolation coefficient to n = 2, which means that the electrode rod spacing used now is twice the original (2X). Select the first electrode rod as A, skip one electrode rod and select the third electrode rod as M, skip another electrode rod and select the fifth electrode rod as N, and finally select the seventh electrode rod as B. Measure under this configuration, and record the result at point c. Similarly, continue in this mode to form the measurement point sequence in row c.

[0065] S405, continue to increase the isolation coefficient n to n = 4. The final test result is a reversed trapezoid. The measured data is processed by the high-density resistivity method host 6 and imported into the computer to build a model to obtain the apparent resistivity profile of the entire trapezoidal section, from Figure 7 which the depth of the fracture can be read.

[0066] S5, insert the electrode rod 1 into the slope body to the maximum depth of the three fissures to establish the in-situ test system of the slope fissure parameters, move all the electrodes 2 on the electrode rod 1 to the same height as the slope surface and fix them, and measure the slope surface fissure parameters: inject the conductive water gel into all the fissures on the slope surface until it is flush with the slope surface, divide the slope surface into several equal rectangles according to 1 / 10-1 / 5 of the length and width of the slope, insert the electrode rod 1 at the corners of the rectangle, and the insertion depth is h max . Move the electrodes 2 on the electrode rod 1 to the probe at the same height as the slope surface and fix them, connect all the cables 3 connected with the electrode rod to the multi-channel electrode switching device 5, and after power on, the apparent resistivity section of each adjacent test area composed of four electrode rods 1 can be measured, the apparent resistivity cross section of the slope surface section can be finally obtained by combining the test results of all the test areas, and the number of the slope surface section fissures, the length, width and area of each fissure, and the specific position of the fissure on the section can be obtained through the output results of the host computer.

[0067] In some specific embodiments, the electrode rod 1 distribution of the test system established in S5 is as follows Figure 5 、 Figure 6 , including the underground electrode 2 and the surface power supply electric energy conversion device 7, the high-density resistivity method host computer 6, and the multi-channel electrode switching device 5. Specifically, a plurality of electrode rods 1 are inserted into the slope body to be measured, the movable electrodes 2 are arranged on the electrode rods 1, a plurality of probes are arranged on the electrode rods 1, the probes are specifically movable conductive probes, and the probes are used to adjust the measurement depth and realize the conduction between the electrodes 2 and the multi-channel electrode switching device 5.

[0068] In some possible embodiments, four electrode rods 1 are arranged as a group, the electrode rods A and B are current input and output ends, and the electrode rods M and N are voltage measurement electrode rods. By moving and fixing the electrodes 2 on the electrode rods 1, the fissure parameters at different depth sections can be measured.

[0069] In some specific embodiments, the high-density resistivity method host computer 6 is further connected with the multi-channel electric energy conversion device 7, the electric energy conversion device 7 is used for system power supply, specifically, the input electric energy is converted into the electric energy form required by the high-density resistivity method, and the electric energy of the electric energy conversion device 7 comes from a small generator set connected therewith.

[0070] In some specific embodiments, the function of the multi-channel electrode switching device 5 is to realize the automatic selection and switching of multiple electrodes. The multi-channel electrode switching device 5 is connected with the electrode rods 1 through the cables 3, which ensures that the high-density resistivity method host computer can accurately identify and record the resistivity data from a specific layer. The multi-channel electrode switching device 5 ensures the realization of subsequent data processing, calculation and imaging analysis.

[0071] In the present embodiment, the high-density resistivity method host 6 adopts the UltraMarker A4 time-frequency high-density electrical method instrument independently developed by Guoke (Chongqing) Instrument Co., Ltd. Different models can be selected according to needs, as long as the device can complete the current injection of the electrode 2, measure the voltage drop generated by the current in the electrode array, multi-electrode switching and control, power management, and has multiple communication interfaces, which are within the disclosure range of the present embodiment. The electrical energy used in the test process is provided by a portable small wind turbine generator set 8 placed on the roadside. The high-speed driving of passing vehicles drives the wind turbine blade to rotate and thus generates electrical energy.

[0072] In some specific embodiments, the fracture parameters include fracture length, width and fracture area, and the position of the fracture on the section.

[0073] In the present embodiment, the multi-channel electrode switching device 5 is connected with the electrode rod 1, and the conduction with the electrode 2 is realized through the movable probe arranged on the electrode rod 1.

[0074] S6, measuring the fracture parameters of each layer and the bulk fracture rate of the slope;

[0075] h max The slope surface is evenly divided into m segments, each with a length of x, and a probe is arranged at each end of each segment. After the fracture parameters of the slope surface are tested, the electrode 2 is lowered by x each time and fixed with the probe at the position, and then the electrical measurement is performed. Finally, the fracture length, width and area of the section with an integer multiple of x in depth can be measured. The fracture parameters and depth are introduced into the computer, and the three-dimensional spatial form of the fracture is determined through the modeling software to obtain the bulk fracture rate of the measured slope.

[0076] In some possible embodiments, the modeling software adopts 3D Studio Max, and the modeling result is as shown in Figure 9 .

[0077] In some possible embodiments, the hydrogel is specifically a high-conductivity hydrogel, which takes agarose gel as a carrier and embeds high-conductivity carbon nanotubes (CNTs) to enhance the electrical performance. The specific formula of the hydrogel in the present embodiment includes: the mass ratio of agarose powder is 10-12 parts, the mass ratio of carbon nanotubes is 0.5-1.5 parts, and the mass ratio of sodium chloride (NaCl) powder is 18-20 parts. The preparation process is specifically as follows: first, dissolve the sodium chloride powder in 90-110 mass parts of deionized water to prepare a NaCl solution; then, place the agarose powder and carbon nanotubes in a high-efficiency mixing device and stir thoroughly to form a uniform solid mixture; finally, slowly add the NaCl solution to the above-mentioned solid mixture while continuously stirring until a uniformly dispersed agarose hydrogel is obtained.

[0078] The experimental results show that the conductivity of the hydrogel prepared in this embodiment is improved by 80%-90% compared with the untreated agarose gel. In addition, when the hydrogel is applied to the surface of the soil and dried, the tensile strength of the soil body can be significantly improved, with an increase of 25%-40%. This improvement is mainly due to the physical entanglement between the hydrogel and the soil particles and the additional mechanical support provided by the carbon nanotubes, thereby enhancing the overall adhesion and structural stability of the soil body.

[0079] After the hydrogel is injected into the soil cracks in this embodiment, due to the excellent flowability and good extensibility of the hydrogel, it can effectively fill the cracks and promote the combination of the soil on both sides. After treatment, not only the tensile strength of the soil is significantly improved, but also the further expansion of the cracks is prevented by the presence of the hydrogel, enhancing the overall stability and durability of the soil. The mechanism of action of the hydrogel in the cracks is reflected in three aspects: first, enhancing adhesion. The agarose component in the hydrogel forms physical entanglement with the soil particles, while the carbon nanotubes provide additional mechanical support, increasing the adhesion strength of the crack interface. Second, constructing an electrically conductive network. The carbon nanotubes form a continuous electrically conductive network in the hydrogel matrix, which not only improves the electrical conductivity of the material, but also may accelerate the curing process of the hydrogel through induction heating and other methods, further strengthening its combination with the soil. Finally, ductility and flexibility. The high ductility and flexibility of the hydrogel itself enable it to deform without breaking when subjected to external forces, effectively buffering and dispersing stress and preventing the reoccurrence or expansion of cracks.

[0080] Example 1

[0081] S101, according to the geological survey report, summarize the measured soil slope geological survey data and slope design parameters, wherein the geological survey data includes soil physical and mechanical parameters. The representative area of the measured slope is 10m long and 10m wide. Field research found that there are three most developed cracks with lengths of 1.2m, 1.0m and 0.9m respectively. According to the principle of high-density resistivity method combined with the size of the slope and the size of the crack, the total length L of the measuring line is determined to be 2m, the electrode rod spacing X is taken as 0.15m, the isolation coefficient n is 4, and the detection depth D=nX=0.6m.

[0082] S102, install the instrument

[0083] Inject the high flow and high conductivity hydrogel into the fissure until the hydrogel is substantially flush with the ground, and stop injecting, ensuring that the conductivity at the fissure is different from the surrounding soil. Connect the power conversion device 7 for power supply, the high-density resistivity method host 6, and the multi-channel electrode conversion device 5 with the cable 3. Install the electrode rods 1 on the ground at the midpoint of the fissure width direction on the horizontal plane according to the electrode rod spacing of 0.15 m, the depth of the electrode rod 1 into the soil should not exceed one-tenth of the electrode rod spacing of 0.15 m, and connect the ground electrode rods 1 to the cable 3.

[0084] S103, probe the fissure depth

[0085] Turn on the power supply, and collect the data collected by the electrode rods 1 using the high-density resistivity method host 6. After collection, perform data processing through the inversion software in the host, and the processing steps are as follows: import data - verify data reliability - eliminate negative values - parameter setting - inversion processing - convergence detection - detail adjustment. According to the apparent resistivity section map obtained by inversion and the difference value between high resistivity (normal soil) and low resistivity (hydrogel in the fissure), the fissure depth h is determined to be 0.5 m, 0.48 m, and 0.4 m, respectively, and the maximum value h = 0.5 m among them is taken as the maximum depth that the fissure in the to-be-measured region can develop. The apparent resistivity section map obtained by inversion of the fissure with h = 0.5 m is shown in FIG. 2. Figure 7

[0086] S2, measure the slope surface fissure parameters

[0087] According to the maximum fissure depth h determined in the S1 step, insert the electrode rods 1 into the slope body to a depth of h = 0.5 m. Move the electrodes 2 on the electrode rods 1 to the same height as the slope surface, make the electrodes 2 contact and fix the probes at that place, connect the cable 3 on the electrode rods 1 to the multi-channel electrode conversion device 5, and obtain the apparent resistivity section map in each test area after power on. Combine the test results of all test areas together to obtain the apparent resistivity cross-sectional view of the slope surface section as shown in FIG. 3. Figure 8 Figure 8 According to the apparent resistivity cross-sectional view of the slope surface section, the number of fissures in the slope surface section is 5, and the slope surface fissure rate can be obtained by combining the fissure area parameters in each test area as follows:

[0088]

[0089] wherein: ξ s is the slope surface fissure rate, A i is the fissure area in the ith test area, j is the number of test areas, and A is the area of the entire to-be-measured region. Substituting the data into the calculation, the slope surface fissure rate is obtained to be 5.13%.

[0090] ​​S3, measure the crack parameters of each layer and the bulk crack rate of the whole region

[0091] After the test of the crack parameters of each layer is completed, the electrode 2 is moved downward by 0.1 m each time and is in contact with the probe arranged on the electrode rod 1 for fixation. After being electrified, the number of cracks, the length, the width and the crack area of each crack at the section with the depth of 0.1 m integer times can be measured. The measured crack parameters of each layer are corresponded with the depth and are imported into the computer. The three-dimensional spatial form of the cracks is calculated through the modeling software. Finally, the bulk crack rate of the whole test region can be obtained. The expression of the bulk crack rate is as follows:

[0092]

[0093] wherein, ξ v is the bulk crack rate, V i is the volume of the ith crack, k is the number of cracks, A is the area of the whole region to be measured, and H is the test depth. The bulk crack rate of the slope body is calculated to be 1.27% by substituting the data.

[0094] Each embodiment in the specification is described in a relevant manner. The same or similar parts between each embodiment can be referred to each other. Each embodiment mainly describes the difference from other embodiments. Especially, the system embodiment is basically similar to the method embodiment, so the description is relatively simple. The relevant parts can be referred to the part of the method embodiment.

[0095] The above only describes the preferred embodiments of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application is included in the protection scope of the present application.

Claims

1. A method for in-situ testing of slope crack parameters based on resistivity method, characterized in that, Includes the following steps: S1. On-site survey to select three of the most developed fissures on the slope and inject conductive hydrogel into these fissures; S2. Determine the total length of the survey lines for the three fractures obtained in S1. L Electrode rod spacing X Isolation coefficient n And calculate the detection depth D=nX ; S3. Based on the data determined in S2, move the electrode rod (1) at intervals... X The electrode grid is arranged and connected to the electrode rods (1) via cables (3) to form a vertical electrode grid. The electrode grid is then connected in series with the cables (3) via a multiplex electrode conversion device (5) to the high-density resistance method host (6), so that the high-density resistance method host (6) can collect data from each electrode rod (1). The electrode mesh is placed at the midpoint of the width direction on the horizontal surface of the crack; S4. Determine the electrode rod (1) used for power supply and the electrode rod (1) used for measurement during the measurement process. Use the high-density resistance method host (6) to convert the voltage data collected by each electrode rod (1) into resistivity data, determine the apparent resistivity at each measurement point, and perform two-dimensional inversion calculation on the apparent resistivity to obtain the high-density resistance method apparent resistivity cross-sectional distribution map of the three fractures along the depth direction. Finally, determine the depth of the three fractures. h 1 , h 2 , h 3 The maximum value among the three is taken as the depth of the deepest fracture on the slope surface under test, denoted as . h max ; S5. Inject conductive hydrogel into all the cracks on the slope until it is flush with the slope surface. Divide the slope surface into multiple rectangles according to 1 / 10 to 1 / 5 of the length and width of the slope. Insert electrode rods (1) at the corners of the rectangles and redistribute the electrode rods (1). The insertion depth is set to [insert depth here]. h max Move all electrodes (2) on the electrode rods (1) to the probe at the same height as the slope surface and fix them in place to detect and measure the slope surface crack parameters. S6. Measure the fracture parameters of each layer and the volumetric fracture rate of the slope.

2. The in-situ testing method for slope crack parameters based on resistivity method according to claim 1, characterized in that, The spacing of the electrode rods (1) in S2 X 1 / 10 to 1 / 15 L between.

3. The in-situ testing method for slope crack parameters based on resistivity method according to claim 1, characterized in that, The specific process for determining the apparent resistivity cross-sectional distribution map of the high-density resistivity method in S4 is as follows: S401, Set the spacing between the electrode rods (1) to be X The first and fourth electrode rods (1) were selected as power supply electrode rods A and B, and the second and third electrode rods (1) were selected as measuring electrode rods M and N for measurement; the midpoint between the measured points M and N, at a depth of X The underground resistivity characteristics are marked as point a; S402, Maintain the spacing between electrode rods (1) as X The second and fifth electrode rods (1) were selected as power supply electrode rods A and B, and the third and fourth electrode rods (1) were selected as measuring electrode rods M and N for measurement; the midpoint between the measured points M and N, at a depth of X The underground resistivity characteristics are marked as point b; repeat the process of S401~S402 until all measuring points in the row of lines ab are measured. S403, Set the spacing between the electrode rods (1) to 2. X The first and seventh electrode rods (1) were selected as power supply electrode rods A and B, and the third and fifth electrode rods (1) were selected as measuring electrode rods M and N for measurement; the midpoint between the measured points M and N, at a depth of 2 X The underground resistivity characteristics are marked as point c; repeat the process of S403 until all measuring points in this row of measuring points are measured; S404, the spacing between the electrode rods (1) is 3 X 4 X The measurements were performed according to the S403 method. The measured data were processed by the high-density resistance method host (6) and modeled as the apparent resistivity map of the cross section.

4. The in-situ testing method for slope crack parameters based on resistivity method according to claim 1, characterized in that, The process of S5 detection and measurement of slope surface crack parameters is as follows: the electrode (2) is moved to the probe on the electrode rod (1) located on the slope surface, and all the cables (3) connected to the electrode rod are connected to the multi-electrode conversion device (5); after the measurement of each rectangular test area is completed, the data is processed by the high-density resistance method host (6) to determine the apparent resistivity cross section of the slope surface section, and the number of cracks, the length, width and area of ​​each crack and the specific location of the crack on the cross section are determined by the output results of the host, thereby determining the slope surface crack rate.

5. The in-situ testing method for slope crack parameters based on resistivity method according to claim 4, characterized in that, The specific method for determining the surface fracture ratio is as follows: ； in: The slope surface fracture ratio, For the first The area of ​​the crack in each test region. j The number of test areas. This represents the area of ​​the entire region to be measured.

6. The in-situ testing method for slope crack parameters based on resistivity method according to claim 1, characterized in that, In S5, four electrode rods (1) are grouped together to form a rectangular test area, where the current input terminals are electrode rods A and B; the measuring electrode rods are... M , N .

7. The in-situ testing method for slope crack parameters based on resistivity method according to claim 1, characterized in that, The specific process of S6 is as follows: the electrode rod (1) is divided into equal parts. m Segment, the length of each segment is denoted as x Probes are placed at both ends of each segment to fix the electrode (2) at a distance from the slope surface. x Connect the cable (3) to the multi-electrode conversion device (5) on the probe at the location to begin measurement; when the distance from the slope surface depth is x After the layer measurement is completed, move electrode (2) down to the next probe and measure again until the depth is measured. h max At; the depth is obtained x The fracture parameters at integer multiples of the cross section are used to establish a three-dimensional spatial model of the fracture parameters, and the volumetric fracture rate of the entire slope is determined based on the three-dimensional spatial model.

8. The in-situ testing method for slope crack parameters based on resistivity method according to claim 6, characterized in that, The method for determining the volumetric porosity is as follows: ； in: For volumetric porosity, For the first The volume of the crack, k The number of cracks. The area is the entire region to be measured. H For testing depth.

9. The in-situ testing method for slope crack parameters based on resistivity method according to claim 1, characterized in that, The specific components of the hydrogel include: 10-12 parts by weight of agarose powder, 0.5-1.5 parts by weight of carbon nanotubes, and 18-20 parts by weight of sodium chloride; The hydrogel is prepared by the following method: First, sodium chloride powder is dissolved in 90-110 parts by mass of deionized water to prepare a sodium chloride solution. Then, agarose powder and carbon nanotubes are mixed and stirred to obtain a mixed powder. After stirring evenly, the prepared sodium chloride solution is slowly added to the mixed powder.

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